Asian Spine Journal

pISSN 1976-1902
eISSN 1976-7846

Asian

Spine Journal
Official Journal of the Asia Pacific Spine Society (APSS),
Middle East Spine Society (MESS), Association of Spine Surgeons of India (ASSI),
Taiwan Spine Society (TWSS), and Korean Society of Spine Surgery (KSSS),
Chinese Spine Society of Medicine Education (CSSME)

Volume 15 ^ Number Supplement 1 ^ June 2021

Volume 15 ^ Supplement 1 ^ June 2021

APSS-APPOS 2021
(13th Combined Meeting of Asia Pacific Spine Society &Asia Pacific Paediatric Orthopaedic Society)9-12 June 2021,
Kobe International Conference Center

Pages 1-177

www.asianspinejournal.org

AsianSpine Journal

www.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Official Journal of the Asia Pacific Spine Society (APSS),
Middle East Spine Society (MESS), Association of Spine Surgeons of India (ASSI),
Taiwan Spine Society (TWSS), and Korean Society of Spine Surgery (KSSS),
Chinese Spine Society of Medicine Education (CSSME)

Aims & Scope

Asian Spine Journal (Asian Spine J), the official journal of the Asia
Pacific Spine Society (APSS), Middle East Spine Society (MESS),
Association of Spine Surgeons of India (ASSI), Taiwan Spine Society(TWSS), Chinese Spine Society of Medicine Education (CSSME),
and Korean Society of Spine Surgery (KSSS), is an international peerreviewed journal which publishes articles related to basic and clinicalresearches of all spine fields bimonthly in end of February, April, June,
August, October, and December. Asian Spine Journal was founded in
2007.
The journal aims to promote communications among spine surgeons
especially in Asian countries regarding spine problems and to provide
Asian spine surgeons more opportunities to publish their works ininternational journal. All manuscripts should be creative, informative
and useful for the diagnosis and treatment of spine problems.
Manuscripts regarding disease and treatment which shows morecharacteristic features in Asian people would be preferable. Every
researcher who has interested in the aims and scope of Asian Spine
Journal is encouraged to submit the papers from all over the world.

Copyright © 2021 Korean Society of Spine Surgery

Articles published in Asian Spine Journal are open-access, distributed
under the terms of the Creative Commons Attribution NonCommercial License (http://creativecommons.org/licenses/bync/4.0/), which permits unrestricted non-commercial use, distribution,and reproduction in any medium, provided the original work is
properly cited.
Submitting an article to Asian Spine Journal implies that theauthors confirm: that all authors read the article and approved of its

publication, that the article is original and has not been published
before, that it is not under consideration for publication elsewhere, andthat copyrights of all published materials, including figures, are owned
by Korean Society of Spine Surgery.

Subscription Information• Korean Society of Spine Surgery will send Asian Spine Journal
for free to some important individuals and institutions. The
subscription fee will be charged only for those issues that wererequested by written order. The subscription fee includes postal andhandling charges.
• For individual subscribers, the annual subscription fee is 20,000 won(Korean) or 30 US dollars (International). The subscription fee for asingle issue is 10,000 won (Korean) or 15 US dollars (International).
For institutional subscribers, there will be no subscription fee until
2015.
• No. of circulation of paper journal:- ‌Domestic (The Korean Medical Library Association, National
Assembly Library, etc.) 730 copies,- Overseas (The Library; various regions in 18 countries) 90 copies.
• To subscribe to Asian Spine Journal, please contact the editorial
office for detailed information (spinepjb@catholic.ac.kr).

Electronic Edition

A free full-text service both in the XML and PDF formats is available
at our home page (http://www.asianspinejournal.com or http://www.
asianspinejournal.org). No registration or subscription is required foraccess to the electronic edition of Asian Spine Journal.

■ Executive Committee
Yung-Khee Chung, Jae-Yoon Chung, Chong-Suh Lee, Hak-Sun Kim, Jong-Beom Park, Jae Hyup Lee, Kyu-Jung Cho, Arvind Jayaswal■ Editorial OfficeCorrespondence for subscriptions, reprints, address changes, and advertisements should be sent to the address below:
Asian Spine Journal
Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea,
88, Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea
Tel: +82-2-3010-3549, Fax: +82-2-3010-8555, E-mail: spinecjh@gmail.com■ Publisher Office
Korean Society of Spine Surgery
Department of Orthopedic Surgery, SMG-SNU Boramae Medical Center, 20, Boramae-ro 5-gil, Dongjak-gu, Seoul 07061, Korea
Tel: +82-2-831-3413, Fax: +82-2-831-3414, E-mail: korspine@hanmail.net■ Printing Office
Newest Medicine Company
Choisin B/D 27-11, Dongho-ro 24-gil, Jung-gu, Seoul 04617, Korea
Tel: +82-2-2263-4723, Fax: +82-2-2263-4726, E-mail: newmedj115@gmail.com
Asian Spine Journal is indexed/tracked/covered by PubMed, PubMed Central, KoreaMed, Synapse, KoMCI, CrossRef, Scopus, Google Scholar, and DOAJ .
This paper meets the requirements of KS X ISO 9706, ISO 9706-1994 and ANSI/NISO Z.39.48-1992 (Permanence of paper).

www.asianspinejournal.org

Asian
Spine Journal

Editorial Board

Editor-in-Chief
Hak-Sun Kim

pISSN 1976-1902 · eISSN 1976-7846

Yonsei University, Orthopaedic Surgery, Korea

Editor-in-Chief Emeritus
Jae-Yoon Chung

Hyundae Hospital, Orthopaedic Surgery, Korea

Chong-Suh Lee

Sungkyunkwan University, Orthopaedic Surgery, Korea

Abdulaziz Al-Mutair

Alrazi Hospital, Orthopaedic Surgery, Kuwait

Howard S An

Rush University, Orthopaedic Surgery, USA

Mohd Hisam Muhamad Ariffin	National University of Malaysia, Orthopaedic Surgery, Malaysia
Azharuddin Abdurrahman

Syiah Kuala University, Orthopaedic Surgery, Indonesia

Siddharth A. Badve	‌Hartsville Orthopedics and Sports Medicine, Orthopaedic Surgery,India

Jong-Min BaikGachon University, Orthopaedic Surgery, Korea

Aju Bosco	‌Tamil Nadu Govt. Multi Super Speciality Hospitals, Orthopaedic

Deputy Editors

Surgery, India

Jae Hwan Cho

Asan Medical Center, University of Ulsan, Orthopaedic Surgery, Korea

Rafael Bundoc

University of the Philippines, Orthopaedic Surgery, Philippines

Helton Luiz Aparecido Defino

University of São Paulo, Biomechanics, Brazil

Ram Chaddha

Global Hospital Mumbai, Orthopaedic Surgery, India

Ashish Diwan

St. George Hospital, Orthopaedic Surgery, Australia

Rupinder Singh Chahal

Sir Ganga Ram Hospital, Orthopaedic Surgery, India

Mohamed Mohi Eldin

Cairo University, NeuroSurgery, Egypt

Chris Yin Wei Chan

University of Malaya, Orthopaedic Surgery, Malaysia

Arvind Jayaswal

All India Institute Of Medical Sciences, Orthopaedic Surgery, India

Ying Kei Chan

Canossa Hospital, Orthopaedic Surgery, Hong Kong

Han Jo Kim

Hospital for Special Surgery, Orthopaedic Surgery, USA

Dong-Gune Chang

Inje University Orthopaedic Surgery, Korea

Morio Matsumoto

Keio University, Orthopaedic Surgery, Japan

Michael Chang	Sonoran Spine Research and Education Foundation, Orthopaedic

S. Rajasekaran

Ganga Hospital, Orthopaedic Surgery, India

Pierre Roussouly

Hospital of Massues, Orthopaedic Surgery, France

Zhaomin Zheng

Sun Yat-Sen University, Orthopaedic Surgery, China

Publisher
Kyu-Jung Cho

Inha University, Orthopaedic Surgery, Korea

Managing Editor
Sung Hoon Choi

Hanyang University, Orthopaedic Surgery, Korea

Surgery, USA

Sam Yeol Chang

Seoul National University, Orthopaedic Surgery, Korea

Jason Cheung

The Hong Kong University, Orthopaedic Surgery, Hong Kong

Harvinder Singh Chhabra

Indian Spinal Injuries Centre, Orthopaedic Surgery, India

Chee Kidd Chiu

University of Malaya, Orthopaedic Surgery, Malaysia

Kyu-Jung Cho

Inha University, Orthopaedic Surgery, Korea

Samuel Cho

The Mount Sinai Hospital, Orthopaedic Surgery, USA

Woojin Cho

Albert Einstein College of Medicine, Orthopaedic Surgery, USA

John Choi

The Avenue Hospital in Windsor, Orthopaedic Surgery, Australia

Yong-Soo Choi

Kwangju Christian Hospital, Orthopaedic Surgery, Korea

Bharat Dave	Stavya Spine Hospital & Research Institute, Orthopaedic Surgery, India
Soundararajan Dilip

Ganga Hospital, Orthopaedic Surgery, India

Ethics Editor

Abdel Hafiz Shehab Eldin

El-Sahel Teaching Hospital, Neurosurgery, Egypt

Sun HuhDavid Essig	Northwell Health Orthopaedic Institute at Great Neck, Orthopaedic

Parasitology, Hallym University, Korea

Manuscript Editor
Hyun Joo Kim

InfoLumi, Korea

Surgery, USA

Michael Faloon

Seton Hall University, Orthopaedic Surgery, USA

Atul Goel

King Edward Memorial Hospital, Neurosurgery, India

Yoon Ha

Yonsei University, Neurosurgery, Korea

Yong Hai

Capital Medical University, Orthopaedic Surgery, China

Mitchell Hansen

Lingard Private Hospital, Neurosurgery, Australia

Jae-Young Hong

Korea University, Orthopaedic Surgery, Korea

Seung-Jae Hyun

Seoul National University, Neurosurgery, Korea

Jose Manuel Ignacio	University of the Philippines-Manila, Orthopedic Surgery, Philippines
Soonchunhyang University, Neurosurgery, Korea
Soo-Bin Im
Komang IriantoSurabaya Medical University, Orthopaedic Surgery, Indonesia

AsianSpine Journal

www.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Yasuo Ito

Ise Red Cross Hospital, Orthopaedic Surgery, Japan

Jin-Sung Park

Sungkyunkwan University, Orthopaedic Surgery, Korea

Hae-Dong Jang

Soonchunhyang University, Orthopaedic Surgery, Korea

Jong-Beom ParkThe Catholic University of Korea, Orthopaedic Surgery, Korea

Jose María Jimenez

Mexican Social Security Institute, Orthopaedic Surgery, Mexico

Kun-Bo Park

Severance Children’s Hospital, Pediatric Orthopaedics, Korea

Chang-Nam Kang

Hanyang University, Orthopaedic Surgery, Korea

Sang-Min Park

Seoul National University, Orthopaedic Surgery, Korea

Rishi Kanna

Ganga Hospital, Orthopaedic Surgery, India

Sehan Park

Dongguk University, Orthopaedic surgery, Korea

Yoshiharu Kawaguchi

University of Toyama, Orthopaedic Surgery, Japan

Se-Jun Park

Sungkyunkwan University, Orthopaedic Surgery, Korea

Mamoru Kawakami	Wakayama Medical University Kihoku Hospital, Orthopaedic Surgery, Japan

Jiwon Park

Korea University, Orthopaedic Surgery, Korea

Kyung-Chung Kang

Kyung Hee University, Orthopaedic Surgery, Korea

Odysseas Paxinos

Hellenic Air Force, Orthopaedic Surgery, Greece

Chi Heon Kim

Seoul National University, Orthopaedic Surgery, Korea

Rabindra L. Pradhan

Kathmandu Medical College, Orthopaedic Surgery, Nepal

Dae-Geun Kim

Soonchunhyang University, Orthopaedic Surgery, Korea

Yong Qiu

Nanjing University Drum Tower Hospital, Orthopaedic Surgery, China

Ho-Joong Kim

Seoul National University, Orthopaedic Surgery, Korea

Moshiur Rahman

Holy Family Red Crescent Medical College, Neurosurgery, Bangladesh

Hyeun Sung Kim

Nanoori Hospital, Neurosurgery, Korea

Alejandro Reyes-Sánchez National Institute of Rehabilitation, Spinal Surgery, Mexico

Keung Nyun Kim

Yonsei University, Neurosurgery, Korea

Kee-Won Rhyu

The Catholic University of Korea, Orthopaedic Surgery, Korea

Sang Il Kim

The Catholic University of Korea, Orthopaedic Surgery, Korea

Yohan Robinson

Armed Forces Centre for Defense Medicine, Spine Surgery, Sweden

Sang Jun Kim

Sungkyunkwan University, Rehabilitation, Korea

Daisuke Sakai

Tokai University, Orthopaedic Surgery, Japan

Sung-Kyu Kim

Chonnam National University, Orthopaedic Surgery, Korea

Salman Sharif

Liaquat National Hospital and Medical College, Neurosurgery, Pakistan

Sung-Soo Kim

Inje University, Orthopaedic Surgery, Korea

Ajoy Shetty

Ganga Hospital, Orthopaedic Surgery, India

Tae-Hwan Kim

Hallym University, Orthopaedic Surgery, Korea

Anuj Singla

University of Virginia, Orthopaedic Surgery, USA

Yong-Chan Kim

Kyung Hee University, Orthopaedic Surgery, Korea

K S Sivananthan

Fatimah Hospital, Orthopaedic Surgery, Malaysia

Young-Yul Kim

The Catholic University of Korea, Orthopaedic Surgery, Korea

Gbolabo Sokunbi

St. Luke’s University, Orthopaedic Surgery, USA

Arvind Kulkarni

Breach Candy Hospital, Orthopaedic Surgery, India

Kwang-Sup Song

Chung-Ang University, Orthopaedic Surgery, Korea

Naresh Kumar

National University of Singapore, Orthopaedic Surgery, Singapore

Masatoshi Sumi

Kobe Rosai Hospital, Orthopaedic Surgery, Japan

Mun Keong Kwan

University of Malaya, Orthopaedic Surgery, Malaysia

Yu SunPeiking University Third Hospital, Orthopaedic Surgery, China

Ji-Won Kwon

National Health Insurance Service Ilsan Hospital, Orthopedic surgery, Korea

Sahyun Sung

Ewha Womans University Seoul Hospital, Orthopaedic Surgery, Korea

Aron Lazary

Semmelweis Universtiy, Department of Spine Surgery, Hungary

Toshiyuki Takahashi

Fujieda Heisei Memorial Hospital, Neurosurgery, Japan

Byung Ho Lee

Yonsei University, Orthopaedic Surgery, Korea

Gamaliel Tan

Ng Teng Fong General Hospital, Orthopaedic Surgery, Singapore

Gun Woo Lee

Youngnam University, Orthopaedic Surgery, Korea

Nobuhiro Tanaka

Hiroshima University, Orthopaedic Surgery, Japan

Jae-Chul Lee

Soonchunhyang University, Orthopaedic Surgery, Korea

Rushama Tandon

Northern Railway Central Hospital, Orthopaedic Surgery, India

Jung Hwan Lee

Namdarun Rehabilitation Clinic, Korea

Warayos Trathitephun

Chulabhorn hospital, Orthopedic surgery, Thailand

Jung-Kil Lee

Chonnam National University, Neurosurgery, Korea

Nishu Tyagi

Indian Spinal Injuries Centre, Rehabilitation and Telehealth, India

Seung Hwan Lee

Master Yonsei Orthopaedic Clinic, Korea

Shih-Tien Wang

National Yang Ming University, Orthopaedic Surgery, Taiwan

Ka Kin Li

The Hong Kong University, Orthopaedic Surgery, Hong Kong

Chung Chek WongKPJ Kuching Specialist Hospital, Orthopaedic Surgery, Malaysia

Kang Taek Lim

Good Doctor Teun Teun Hospital, Neurosurgery, Korea

Hee Kit Wong

National University of Singapore, Orthopaedic Surgery, Singapore

Gabriel Liu

National University of Singapore, Orthopaedic Surgery, Singapore

Hiroshi Yamada

Wakayama Medical University, Orthopaedic Surgery, Japan

Keith DK Luk

The Hong Kong University, Orthopaedic Surgery, Hong Kong

Wai-Mun Yue

Gleneagles Hospital, Orthopaedic Surgery, Singapore

Hisanori Mihara

South Yokohama Mutual Aid Hospital, Orthopaedic Surgery, Japan

Yasutsugu Yukawa

Wakayama Medical University, Orthopaedic Surgery, Japan

Raghava Dutt Mulukutla Udai Omni Hospital, Orthopaedic Surgery, India

Hao Zhang

Chinese PLA General Hospital, Orthopaedic Surgery, China

Abhay Nene

Hinduja Hospital, Orthopaedic Surgery, India

Feifei Zhou

Peiking University Third Hospital, Orthopaedic Surgery, China

Zairin Noor

Lambung Mangkurat University, Orthopaedic Surgery, Indonesia

Zhao-Ming Zhong

Southern Medical University, Orthopaedic Surgery, China

Orso Lorenzo Osti

University of Adelaide, Orthopaedic Surgery, Australia

Zezhang Zhu

Nanjing University Drum Tower Hospital, Orthopaedic Surgery, China

Mehmet Zileli

Ege University, Neurosurgery, Turkey

Hiroshi Ozawa	Tohoku Medical and Pharmaceutical University, Orthopaedic Surgery, Japan
Dae-Hyun Park

Inje University , Orthopaedic Surgery, Korea

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
Abstracts
PS-BP-1	‌Significance of Vertebral Body Sliding Osteotomy as a Surgical Strategy for the Treatment of Cervical Ossification of the
Posterior Longitudinal Ligament 		
1
Sehan Park, Dong-Ho Lee, Jae Hwan Cho, Chang-Ju Hwang, Choon-Sung Lee

PS-BP-2	‌Comparison of the Clinical and Radiographic Results between Cervical Artificial Disc Replacement and Anterior Cervical Fusion: 10-Year Follow- up Study 		
1
Kai Yan, Chi Ma, Xiao Han, Da He, Wei Tian

PS-BP-3

Deep Learning Pipeline for Automated Detection and Classification of Central Canal, Lateral Recess and Neural Foraminal Stenosis on Lumbar Spine Magnetic Resonance Imaging
2
Jiong Hao Tan, James Thomas Patrick Decourcy Hallinan, Lei Zhu, Kaiyuan Yang, Andrew Makmur,
Diyaa Abdul Rauf Algazwi, Yee Liang Thian, Samuel Lau, Yun Song Choo, Eide Sterling, Qai Ven Yap, Yiong Huak Chan,
Naresh Kumar, Beng Chin Ooi, Hiroshi Yoshioka, Swee Tian Quek

PS-BP-5

Prediction of Final Outcome after Posterior Correction with Lower Instrumented Vertebra L3 or L4 for the Correctionof Structural Thoracolumbar/Lumbar Curve-Minimum 5-Year Follow-up
3
Kun-Bo Park, Choon Sung Lee, Sehan Park

PS-BP-6

Better Patient Experience Improves Outcomes in Pediatric Patients with Scoliosis

PS-BP-7

Clarifying the Therapeutic Effect of Grafted Human-Induced Pluripotent Stem Cell-Derived Neurons in Spinal Cord
Injury by Chemically Controlling Neuronal Activity
4

3

Yi Ling Chua

Takahiro Kitagawa, Narihito Nagoshi, Yasuhiro Kamata, Morio Matsumoto, Hideyuki Okano, Masaya Nakamura

PS-BP-8

Long-Term Selective Stimulation of Transplanted Neural Stem/Progenitor Cells for Spinal Cord Injury Improves Locomotor Function Mediated by Increased Synaptic Transmission
5
Momotaro Kawai, Narihito Nagoshi, Kent Imaizumi, Mitsuru Ishikawa, Munehisa Shinozaki, Shinsuke Shibata,
Yusuke Saijo, Yu Suematsu, Takayuki Nishijima, Takashi Yoshida, Takahiro Shibata, Shogo Hashimoto,
Takahiro Kitagawa, Kentaro Ago, Keita Kajikawa, Reo Shibata, Yasuhiro Kamata, Morio Matsumoto, Hideyuki Okano,
Masaya Nakamura

PS-BP-9Novel Biomarkers of Health and Degeneration in Human Intervertebral Discs: In-Depth Proteomic Analysis of Collagen Framework of Fetal, Healthy, Scoliotic, Degenerate and Herniated Discs
6
Dilip Chand Raja Soundararajan, Sharon Miracle Nayagam, Sri Vijayanand Ks, Raveendran Muthurajan, Sunmathi R,
Chitraa Tangavel, Ajoy Prasad Shetty, Rishi Mugesh Kanna, Rajasekaran Shanmuganathan

PS-FP-1-2

Fusion and Subsidence Rates of Vertebral Body Sliding Osteotomy: Comparison of Three Reconstructive Techniquesfor Multilevel Cervical Myelopathy
6
Sehan Park, Dong-Ho Lee, Jae Hwan Cho, Chang Ju Hwang, Choon Sung Lee

PS-FP-1-5

PS-FP-1-6

What is the Risk of Cervical Deformity after Posterior Cervical Decompression Surgery?: A Multicenter Study

7

Shin Oe, Kenta Kurosu, Tomohiko Hasegawa, Satoshi Shimizu, Go Yoshida, Tomotada Fujita, Sho Kobayashi,
Tomohiro Yamada, Koichiro Ide, Keiichi Nakai,Kumiko Yotsuya, Yu Yamato, Tatsuya Yasuda, Tomohiro Banno,
Hideyuki Arima, Yuki Mihara, Hiroki Ushirozako, Yuh Watanabe, Yukihiro Matsuyama

The Effect of Using Lamina Spacer on Postoperative Cervical Alignment and Range of Motion in Double-Door Laminoplasty
8
Akinobu Matsushita, Kenichi Kawaguchi, Hirokazu Saiwai, Keiichiro Iida, Yasuharu Nakashima

PS-FP-1-7K-line (−) in the Neck-Flexed Position Negatively Affects Surgical Outcome of Expansive Open-Door Laminoplasty for
Cervical Spondylotic Myelopathy
8
Satoshi Nori, Narihito Nagoshi, Satoshi Suzuki, Osahiko Tsuji, Eijiro Okada, Mitsuru Yagi, Masaya Nakamura,Morio Matsumoto, Kota Watanabe“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-1-8

Preoperative Severity of Spinal Cord Compression and Its Restoration during the Early Postoperative Period Affect theDevelopment of C5 Palsy
9
Masahiro Mizutani, Takashi Fujishiro, Takuya Obo, Atsushi Nakano, Yoshiharu Nakaya, Sachio Hayama, Yoshitada Usami,
Masashi Neo

PS-FP-1-9

A Multicentre, Prospective, Randomized Controlled Trial Comparing Efficacy and Safety of ProDisc–C to Anterior
Cervical Discectomy and Fusion for Treatment of Symptomatic Cervical Disc Disease10
Naresh Kumar, Leonard Vornov, Chi Chien Niu, Hee-Kit Wong

PS-FP-1-13

Gap between Flexion and Extension Range of Motions: A Novel Indicator to Predict the Loss of Cervical Lordosis after
Laminoplasty for Cervical Spondylotic Myelopathy
10
Takashi Fujishiro, Sachio Hayama, Takuya Obo, Yoshiharu Nakaya, Atsushi Nakano, Yoshitada Usami, Ichiro Baba,
Masashi Neo

PS-FP-1-14

Decompression Status of the Spinal Cord after Cervical Laminoplasty in Various Body Positions and Neck Postures
Observed Using Percutaneous Ultrasonography: Relationship with Neurological Recovery
11
Sachio Hayama, Yoshiharu Nakaya, Atsushi Nakano, Takashi Fujishiro, Toma Yano, Masahiro Mizutani, Kenta Fujiwara,
Masashi Neo

PS-FP-1-16

C6 Radiculopathy Can Cause So-Called C5 Palsy: Comparison to C5 Radiculopathy

12

PS-FP-1-17

Posterior Hybrid Technique for Multi-Level Cervical Spondylotic Myelopathy with Instability

12

PS-FP-1-18

The Feasibility Study of Cervical Pedicle Screwed with a New Individual-Oriented Template by Three-Dimensional
Printing Technology
13

Takumi Tsubakino, Yasuhisa Tanaka, Takeshi Nakamura, Yasutaka Naba, Kota Miyake, Eiketsu Kinjo, Shigeaki Kojo
Hao Zhang, Feng Zeng Guo

Hao Zhang, Wang Zhang

PS-FP-1-19

Anterior Cervical Discectomy and Fusion with Cervical Uncinectomy for Cervical Radiculopathy with Foraminal Stenosis
13
Hao Zhang, Feng Zeng Guo

PS-FP-1-20

Investigation of Diagnostic Imaging Criteria for Developmental Stenosis Based on Cervical Spondylotic Myelopathy in
Young Patients
14
Tsuyoshi Iida, Narihito Nagoshi, Satoshi Suzuki, Osahiko Tsuji, Satoshi Nori, Eijiro Okada, Mitsuru Yagi, Masaya Nakamura,Morio Matsumoto, Kota Watanabe

PS-FP-1-21

Surgical Strategy for the Cervical Kyphosis Patients Associated with Cervical Spondylolisthesis: Three Cases’ Experience
15
Daichi Takahashi, Akira Matsumura, Takashi Namikawa, Ryo Yanai, Hiroaki Nakamura
Hyeongseok Jeon, Yoon Ha, Dong Wuk Son

PS-FP-1-24

A Meta-Analysis of the Efficacy of Botulinum Toxin A and Occupational Therapy versus Occupational Therapy Alone
in Children with Upper Limb Spastic Cerebral Palsy
15
Alice Chu, Anugya Mittal, Vaishali Ravikumar, Kunj Jain, Yash Shah, Amy Song, Lauren Hutnik, Anam Purewal,
Sarthak Mohanty, Jen Fu Cheng

PS-FP-1-26

Modified Kurukawa Cervical Laminoplasty Using Iliac Crest Bone Graft as Spacers: Why to Do It Any Other Way? 16

PS-FP-1-27

Preoperative Transverse Area of Spinal Cord Compression Using Quantitative Magnetic Resonance Imaging in Surgically Treated Cervical Spondylotic Myelopathy: A Descriptive Study
17

Aashish Babanrao Ghodke, David Jaffray, Birender Balain

Jon Christian Sanga Manuntag, Lean Angelo Silverio, Ronald Tangente, Romel L. Tan, Ma Ramona Reyes, Wencito Daya

“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

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Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-1-28

Impact of Cervical Alignment for Prognosis of Cervical Spondylotic Amyotrophy: Propensity Score Matching Analysis
17
Masahito Takahashi, Masaaki Tsuji, Kazuhiko Satomi, Takumi Takeuchi, Hideto Sano, Shoichi Ichimura, Naobumi Hosogane

PS-FP-1-29

Usefulness of the Disabilities of the Arm, Shoulder, and Hand in Evaluating Surgical Outcome of Cervical Spine Disorders
18
Nao Otomo, Haruki Funao, Kentato Ideura, Kento Yamanouchi, Norihiro Isogai, Yutaka Sasao, Shigeto Ebata, Ken Ishii

PS-FP-1-30

The Posterolaterally Oriented and Laterally Downward Sloping Facet Joint Is a Risk Factor for Degenerative CervicalSpondylolisthesis and Myelopathy
19
Hiromi Kumamaru, Takeyuki Saito, Shingo Yoshizaki, Yasuharu Nakashima, Katsumi Harimaya

PS-FP-1-33

Accuracy of the Adjustable Aiming Device for Caspar Pin Insertion in Anterior Cervical Spine Surgery: Human Cadaveric Study
19
Torphong Bunmaprasert, Raphi Raphitphan, Nantawit Sugandhavesa, Wongthawat Liawrungrueang

PS-FP-1-34

The Natural History of Patients with Cervical Radiculopathy Treated Conservatively and Correlating with Clinical andMagnetic Resonance Imaging Features after a Mean Follow-up of 33 Months
20
Gowtham Ranga Sai Jallipalli, Saumyajit Basu

PS-FP-1-35

Is Cervical Posterior Fixation Effective for Neck Pain?

20

PS-FP-1-36

Incidence, Prevalence, and Clinical Significance of Modic Changes in Cervical Spine: A Prospective Study

21

PS-FP-1-37

Efficacy of Ultrasound-Guided Nerve Root Block for Cervical Spondylotic C6 Radiculopathy

22

PS-FP-2-1

Spinal Column Phenotypes with Lumbar Developmental Spinal Stenosis:Results from 2,387 Magnetic Resonance Imaging
22

Takeo Furuya, Satoshi Maki, Sho Okimatsu, Takaki Inoue, Atsushi Yunde, Masataka Miura, Gundong Kim, Yasuhiro Shiga,
Kazuhide Inage, Sumihisa Orita, Yawara Eguchi, Masao Koda, Masashi Yamazaki, Seiji Ohtori
Dilip Chand Raja Soundararajan, Hemanth Kumar Arasavalli, Ajoy Prasad Shetty, Rishi Mugesh Kanna,Rajasekaran Shanmuganathan
Shinichi Ishihara

Jason Pui Yin Cheung, Prudence Wing Hang Cheung, Dino Samartzis, Jaro Karppinen, Kenneth Cheung, Marcus Kin Long
Lai

PS-FP-2-2
PS-FP-2-3

Increased Population Risk of Radicular Leg Pain in Lumbar Developmental Spinal Stenosis

23

Jason Pui Yin Cheung, Prudence Wing Hang Cheung, Dino Samartzis, Jaro Karppinen, Kenneth Cheung, Marcus Kin Long
Lai

Effects of Bone Cement Augmentation for Upper Instrumented Vertebra on Adjacent Segment Degeneration in Lumbar Fusions
23
Young-Hoon Kim, Sang-Il Kim, Hun-Chul Kim

PS-FP-2-5
PS-FP-2-7
PS-FP-2-12

The Problems and Measures of L5 Osteotomy

24

Spinal Endoscopic-Full See Technique for the Treatment of Two-Level Lumbar Lateral Recess Stenosis

25

Takashi Kobayashi, Kazuma Kikuchi, Hayato Kinoshita, Ryota Kimura, Eiji Abe, Hajime Murai, Natsuo Konishi, Takahiro Sato,
Yoichi Shimada, Naohisa Miyakoshi
En Song, Ji Zheng Li, Yan Lin Li, You Qing Huang, Fan Bing Li, Xiao Feng Yuan, Xue Song Chen, En Bin Wang,
Xian Guang Yang, Yao Yu Xiang

The Role of Gut-Skin-Spine Axis in the Establishment and Evolution of Human Intervertebral Disc Microbiome andDegenerative Disc Disease25
Dilip Chand Raja Soundararajan, S. Rajasekaran, Sharon Miracle Nayagam, Tangavel Chitraa, K. S. Sri Vijayanand,
Muthurajan Raveendran, Shetty AJoy Prasad, Kanna Rishi Mugesh“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-2-13

The Catastrophization Effects of a Magnetic Resonance Imaging Report on the Patient and Surgeon and the Benefits of‘Clinical Reporting’
26
Dilip Chand Raja Soundararajan, S. Rajasekaran, B. T. Pushpa Bhari, Anand Kumar Behera, Shetty Ajoy Prasad,
Kanna Rishi Mugesh

PS-FP-2-14

Sub-Clinical Infection Can Be an Initiator of Inflammaging Leading to Degenerative Disc Disease: Evidence from Host
Defense Response Mechanisms
26
Dilip Chand Raja Soundararajan, Sharon Miracle Nayagam, Sri Vijayanand KS, Tangavel Chitraa, Muthurajan Raveendran,Shetty Ajoy Prasaad, Kanna Rishi Mugesh, S Rajasekaran

PS-FP-2-15

Dynamic Ultrasound Imaging of Lumbar Multifidus for Assessment of Lumbar Spinal Muscles

27

PS-FP-2-16

Examination of Surgical Procedure for Lower Lumbar Osteoporotic Vertebral Body Fractures

27

PS-FP-2-17

Clinical Relationship between Spinopelvic Alignment and Lumbar Spinal Canal Stenosis in Patients with Rheumatoid
Arthritis28

Yongsoo Choi, Jihoon Park, Sangmin Lee, Seungwoo Shim

Yuji Kasukawa, Naohisa Miyakoshi, Michio Hongo, Yoshinori Ishikawa, Daisuke Kudo, Yoichi Shimada

Shunsuke Ito, Yoichi Iizuka, Eiji Takasawa, Tokue Mieda, Sho Isiwata, Yusuke Tomomatsu, Kazuhiro Inomata, Hideo Sakane,
Koichi Okamura, Hirotaka Chikuda

PS-FP-2-18

Lumbar Disc Degeneration and Vertebral Fracture at Thoracolumbar Junction Are Risk Factors for Chronic Low Back
Pain with Disability: The Wakayama Spine Study
29
Hiroshi Hashizume, Masatoshi Teraguchi, Hiroyuki Oka, Yuyu Ishomoto, Keiji Nagata, Ryohei Kagotani, Hiroki Iwahashi,
Motohiro Okada, Masanari Takami, Shunji Tsutsui, Hiroshi Iwasaki, Akihito Minamide, Yasutsugu Yukawa,
Munehito Yoshida, Noriko Yoshimura, Hiroshi Yamada

PS-FP-2-20

Advanced Glycation End Products Are Associated with the Intensity of Back Pain Symptoms in Patients with Lumbar
Spinal Stenosis
29
Masatoshi Teraguchi, Mamoru Kawakami, Masafumi Nakagawa, Yoshikazu Minetama, Sachika Matsuo, Yoshio Yamamto,
Yoshio Enyo, Yukihiro Nakagawa

PS-FP-2-21

Patient-Reported Outcome of Lower Extremity Improved after Posterior Decompression and Lumbar Interbody Fusion for Degenerative Lumbar Diseases
30
Sung-Min Kim, Yong-Chan Kim, Keun-Ho Lee, Ki-Tack Kim, Kee-Yong Ha, Joonghyun Ahn, Qiang Luo, Seungnam Ko,
Kyeonguk Min

PS-FP-2-22

Prevalence and Characteristics of Osteoporotic Vertebral Fracture in Elderly Patients with Sagittal Imbalance

31

PS-FP-2-26

Effect of Segmental Lordosis on Early-Onset Adjacent Segment Disease after Posterior Lumbar Interbody Fusion

31

PS-FP-2-27

Facet Joint Opening on Computed Tomography Is a Predictor for Poor Clinical Outcomes after Less-Invasive Decompression Surgery for Lumbar Spinal Stenosis
32

Akito Yabu, Masatoshi Hoshino, Yusuke Hori, Shinji Takahashi, Shoichiro Ohyama, Akinobu Suzuki, Tadao Tsujio,
Hidetomi Terai, Sho Dohzono, Ryuichi Sasaoka, Hiromitsu Toyoda, Minori Kato, Akira Matsumura, Takashi Namikawa,
Masahiko Seki, Hiroaki Nakamura
Shinya Okuda, Yukitaka Nagamoto, Shota Takenaka, Masato Ikuta, Tomiya Matsumoto, Yoshifumi Takahashi,
Masayuki Furuya, Motoki Iwasaki

Kentaro Yamada, Hiromitsu Toyoda, Shinji Takahashi, Koji Tamai, Akinobu Suzuki, Masatoshi Hoshino, Hidetomi Terai,
Hiroaki Nakamura

PS-FP-2-29

Osseous Union after Posterior Lumbar Interbody Fusion: Pay Attention to Large Interbody Angle

33

Keichi Nakai, Tomohiko Hasegawa, Yu Yamato, Go Yoshida, Tomohiro Banno, Hideyuki Arima, Shin Oe, Yuki Mihara,
Hiroki Ushirozako, Tomohiro Yamada, Koichiro Ide, Yu Watanabe, Kenta Kurosu, Hirotaka Haro, Jun Takahashi,
Keijiro Mukaiyama, Yukihiro Matsuyama“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-2-30

Symptomatic Post-surgical Lumbar Pseodomeningocoele Treated by Ultrasound Guided Blood Patch Application: A
Case Report
33
Rohit Akshay Kavishwar, Ajoy Prasad Shetty, S. Rajasekaran

PS-FP-2-31

Titanium Cages May Be Superior to Polyetheretherketone Cages in Lumbar Interbody Fusion: A Systematic Review
and Meta-Analysis of Clinical and Radiological Outcomes
34
Jun-Hao Tan, Chin Kai Cheong, Dennis Hey

PS-FP-2-32

Risk Factors for Postoperative Ileus after Oblique Lateral Interbody Fusion: A Multivariate Analysis

35

PS-FP-2-36

A Rare Case of Idiopathic Dorsal Spinal Cord Herniation Perforating the Lamina

35

PS-FP-2-37

Discogenic Low Back Pain Can Be Diagnosed with an Ultrasonographic-Guided Disc Pain Induction Test

36

PS-FP-2-38

Degenerative Lumbar Spondylolisthesis Patients with Movement-Related Low Back Pain Have Less Postoperative Satisfaction after Decompression Alone36

Sung Cheol Park, Sam Yeol Chang, GeunWu Gimm, Hyoungmin Kim, Sujung Mok, Bong-Soon Chang, Choon-Ki Lee
Kento Yamanouchi, Haruki Funao, Kenshi Daimon, Norihiro Isogai, Yutaka Sasa, Shigeto Ebata, Ken Ishii
Keisuke Masuda, Manabu Maeda, Hideki Shigematsu, Akinori Okuda, Sachiko Kawasaki, Yuma Suga, Yusuke Yamamoto,
Yasuhito Tanaka

Ryosuke Hirota, Mitsunori Yoshimoto, Naohisa Miyakoshi, Yoichi Shimada, Toshihiko Yamashita

PS-FP-2-39

Extraforaminal Stenosis at L2–L3 Treated with Microendoscopic Surgery: Report of Two Cases

37

PS-FP-2-40

Giant Thoracic Disc Herniation Surgery

37

PS-FP-2-42

Occurrence Rate of Sacroiliac Joint Disorders before and after Lumbar Surgeries and Treatment Strategies

38

PS-FP-2-43

Technical Pitfalls During Sacroiliac Joint Arthrodesis for Patients with Sacral Dysmorphism Induced by Lumbosacral
Transitional Vertebrae
39

Arihiko Tsukamoto, Mitsunori Yoshimoto, Akimitsu Oyama, Hisashi Obara, Ryunosuke Fukushi, Kouta Kurihara,
Ryousuke Hirota, Izaya Ogon, Noriyuki Iesato, Toshihiko Yamashita
Isao Kitahara

Daisuke Kurosawa, Eiichi Murakami, Hiroshi Ozawa

Daisuke Kurosawa1, Eiichi Murakami1, Hiroshi Ozawa

PS-FP-2-48

Association between Lumbar Segmental Mobility and Intervertebral Disc Degeneration Quantified by Magnetic Resonance Imaging T2 Mapping
39
Izaya Ogon, Hiroyuki Takashima, Yoshinori Terashima, Mitsunori Yoshimoto, Tsuneo Takebayashi, Toshihiko Yamashita

PS-FP-2-49

Diagnostic Performance of Conventional Two-Dimensional Magnetic Resonance Image for L5–S Foraminal Stenosis 40

PS-FP-2-50

The Longitudinal Analysis to Determine Whether the Presence of Current Sexual Activities Among Elderly People Affect Low Back Pain or Not
41

Kohei Takahashi, Myo Min Latt, Takumi Tsubakino, Ko Hashimoto, Toshimi Aizawa, Yasuhisa Tanaka

Shoichiro Ohyama, Masatoshi Hoshino, Shinji Takahashi, Hidetomi Terai, Yusuke Hori, Akito Yabu, Tadao Tsujio,
Hiroaki Nakamura

PS-FP-2-51

Unilateral Lumbar Interbody Fusion versus Conventional Posterior Lumbar Interbody Fusion for Two Lumbosacral
Segments: Clinical and Radiological Outcomes of 1-Year Follow-up
41
Seung-Hyun Choi, Sang-Kyu Son, Weon-Wook Park

PS-FP-2-53

How the Novel Modular Spine Blocks Affect the Adjacent Lumbar Spine on Finite Element Analysis?

PS-FP-2-54

Epidemiology and Burden of Osteoporotic Patients with Spine Fusion Procedures with Pedicle Screws in Japan: A Nationwide Claim Database Analysis
42

42

Jui-Yang Hsieh, Yi-You Huang, Chen-Sheng Chen, Jyh-Horng Wang, Po-Quang Chen

Kotaro Nishida, Anh Bourcet, Mami Ogiri, Hye Jin Park, Kazuko Nishikawa“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-2-55

Short Segmental Lumbar Surgery Improves Health-Related Quality of Life without Limiting Activities of Daily Living:
A Retrospective Study
43
Ryota Kimura, Naohisa Miyakoshi, Michio Hongo, Yuji Kasukawa, Daisuke Kudo, Yoichi Shimada

PS-FP-2-56

Coronal Magnetic Resonance Imaging for Diagnosis of Lumbar Foraminal Stenosis: A Comparative Study of Reliability, Reproducibility, and Interpretation between T1 and T2-Weighted Images
44
Ko Hashimoto, Yasuhisa Tanaka, Toshimi Aizawa, Takumi Tsubakino, Tomowaki Nakagawa, Satoshi Tateda, Kohei Takahashi,
Manabu Suzuki, Takahiro Ohnoki, Naoki Morozumi, Yutaka Koizumi, Tetsuro Sato, Hiroshi Ozawa, Haruo Kanno,
Shoichi Kokubun, Eiji Itoi

PS-FP-2-58

Intradiscal Vacuum Phenomenon: Radiological Factors to Predict the Selective Appearance and a New MorphologicalClassification System
45
Swapnil Sanjay Hajare, Rishi Kanna, S. Rajasekaran, Ajoy Shetty

PS-FP-2-60

The Characteristics of Degenerative Disc Disease: Pfirrmann versus Thompson Grading Systems

PS-FP-2-61

Efficacy of Caudal Neuroplasty versus Transforaminal Epidural Block for Radiating Pain Caused by Lumbar Foraminal
Stenosis
46

45

Kamil Krupa, Dominik Taterra, Przemysław Pękala, Mateusz Paziewski, Wadim Wojciechowski, Tomasz Konopka,
Jerzy Walocha, Krzysztof Tomaszewski

Jihun Park

PS-FP-2-62

Risk Factors Associated with Low Back Pain in Patients with Osteoporosis

46

PS-FP-2-66

Spinopelvic Parameters and Symptomatic Lumbar Degeneration in Nepalese Patients47

PS-FP-2-70

Is Sagittal Spinopelvic Imbalance a Critical Factor for Revision Hip Arthroplasty?

48

PS-FP-2-72

Prevalence and Clinical Correlation of Lumbosacral Transitional Vertebra: An Ambi-Spective Study Based on 4,027
Whole Spine Magnetic Resonance Imaging
48

Yusuke Mimura, Masayuki Miyagi, Kosuke Murata, Tomohisa Koyama, Akiyoshi Kuroda, Ayumu Kawakubo, Yuji Yokozeki,
Eiki Shirasawa, Wataru Saito, Takayuki Imura, Toshiyuki Nakazawa, Gen Inoue, Masashi Takaso
Rabindra L. Pradhan, Bimal K. Pandey, Syed Saddam

Cheng-Min Hsu, Yu-Cheng Yeh, Yu-Chih Lin, Tsung-Ting Tsai, Yu-Han Chang, Pang-Hsin Hsieh, Po-Liang Lai,
Chi-Chien Niu, Hsin-Nung Shih, Lih-Huei Chen, Steve W. N. Ueng, Wen-Jer Chen

Swapnil Sanjay Hajare, Ajoy Shetty, S. Rajasekaran

PS-FP-2-73

Efficacy of Analgesic Cocktail on Epidural Patch for Postoperative Pain Control in Posterior Surgery of Degenerative
Lumbar Spine: Randomized Control Trial Study
49
Surawut Ruchirawan, Satawat Jirapan

PS-FP-2-74

Effect of 3-Months of Romosozumab Treatment on Spinal Surgery: Prospective Study Using Finite Element Analysis 		
50
Koji Ishikawa, Soji Tani, Koki Tsuchiya, Chikara Hayamawa, Ryo Yamamura, Akira Matsuoka, Hiroshi Maruyama,
Toshiyuki Shirahata, Yoshifumi Kudo, Tomoaki Toyone, Katsunori Inagaki

PS-FP-3-1
PS-FP-3-2
PS-FP-3-5
PS-FP-3-6

Proposal of New Classification and Treatment Strategy for Transverse Fractures of the C2 Body

50

An Analysis of 49 Cases with Pedicle Fractures of the c2 Axis: Is Surgery Necessary?

51

Direct Osteosynthesis in Hangman’S Fracture Risks Vertebral Artery Injury

51

Jong-Beom Park, Sung-Kyu Kim
Jong-Beom Park, Sung-Kyu Kim

Tokumitsu Mihara, Shinji Tanishima, Chikako Takeda, Msaki Yoshida, Hideki Nagashima

Significance of the Neurological Level of Injury as a Prognostic Predictor for Motor Complete Cervical Spinal Cord Injury Patients
52
Osamu Kawano, Takeshi Maeda, Hiroaki Sakai, Muneaki Masuda, Yuichiro Morishita, Tetsuo Hayashi, Kensuke Kubota,
Kazu Kobayakawa, Kazuya Yokota, Hironari Kaneyama“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-3-7

Clinical Features and Post-treatment Complications of C2 Odontoid Fractures: A Retrospective Analysis Using a National Inpatient Database in Japan
52
Akira Honda, Yoichi Iizuka, Nobuaki Michihata, Tokue Mieda, Eiji Takasawa, Sho Ishiwata, Hideo Yasunaga,
Hirotaka Chikuda

PS-FP-3-8

Surgical Strategy as Anterior Submandibular Retropharyngeal Odontoid Osteotomy and Posterior Occipitocervical Fusion with C1 Laminoplasty for Fixed Atlantoaxial Dislocation Associated with Odontoid Fracture Malunion
53
Kuang-Ting Yeh, Tien-Wu Wu, Chiu-Yu Tzai, Ing-Ho Chen

PS-FP-3-9Anterior C2–3 Fusion Surgery Alone for Highly Displaced Hangman's Fracture with Severe Angulation of C2–3 ofMore Than 30°
53
Jong-Beom Park, Hyoung-Yeon Seo

PS-FP-3-10

Is Only Anterior Stabilization Enough in Three Column Injuries of Sub-axial Cervical Spine?: A Long-Term Retrospective Analysis of 78 Patients
54
Manojkumar Basavareddy Gaddikeri, Sudhir K. Srivastava, Aditya Raj, Sunil Bhosale

PS-FP-3-11

Efficiency of Long Lateral Mass Screw

55

PS-FP-3-12

Role of Riluzole in Acute Traumatic Cervical Spinal Cord Injury with Incomplete Neurological Deficit: A
Prospective, Randomized Control Study55

Seiya Watanabe, Kazuo Nakanishi

Guna K. Pratheep, Vibhu Krishnan Viswanathan, Rajasekaran Shanmuganathan, Ajoy Prasad Shetty, Rishi Mugesh Kanna

PS-FP-3-13

Traumatic Cervical Spinal Cord Injury after Cervical Laminoplasty for Ossification of Posterior Longitudinal
Ligament
56
Hironari Kaneyama, Yuichiro Morishita, Osamu Kawano, Takuaki Yamamoto, Takeshi Maeda

PS-FP-4-5

Mesh-Hold Bone Filling Container Vertebroplasty in the Treatment of Osteoporotic Vertebral Fractures with
Posterior Wall Injury: A Study of the Clinical Efficacy and Safety
56
En Song, Ji Zheng Li, Yan Lin Li, You Qing Huang, Fan Bing Li, Xiao Feng Yuan, Xue Song Chen, En Bin Wang,
Xian Guang Yang, Yao Yu Xiang

PS-FP-4-7
PS-FP-4-8

Clinical Safety Study of Photobiomodulation Treatment of Acute Spinal Cord Injury by Scattering Fiber

57

Zhuowen Liang, Tan Ding, Xueyu Hu, Xiaoshuang Zuo, Zhe Wang

A Novel Steerable Percutaneous Balloon Kyphoplasty for Treatment of Thoracolumbar Osteoporotic Vertebral Compression Fractures
58
En Song, Ji Zheng Li, Fan Bing Li, Xiao Feng Yuan, En Bin Wang, Yao Yu Xiang, Xian Guang Yang

PS-FP-4-9

Mid-Term Results of Anterior-Posterior Simultaneous Reconstruction for Lower Lumbar Spine Injury in the Elderly		
58
Yu Maeda

PS-FP-4-10

Comparison of Mini Open Wiltse Approach with Conventional Posterior Approach in Patients with Single Segment
Unstable Thoracolumbar Fractures
58
Muhammad Siddique Hamid, M. Hasnain Abbas, Ali Hassan Butter, Muhammad Hanif Mian, M. Tariq Sohail

PS-FP-4-12

Comparative Study to Evaluate Surgical Outcomes between Direct Lateral Corpectomy with Percutaneous Pedicle
Screws and Posterior Spinal Fusion with Vertebroplasty for Osteoporotic Thoracolumbar Vertebral Fracture
59
Hirotaka Haro, Tetsuro Ohba, Koji Fujita, Kohtaroh Oda, Nobuki Tanaka

PS-FP-4-13

Treatment of Unstable Pelvic Ring Fractures (AO Type C) with Minimum Invasive Spino-Pelvic Fixation

PS-FP-4-14

Surgical Treatment of Post-traumatic Kyphosis in Thoraco-Lumbar Spine: A Retrospective Analysis of Indications andLong-Term Outcome of Surgery
60

60

Takuya Morita, Takuya Taoka, Tomoyuki Takigawa, Yasuo Ito

Rohit Akshay Kavishwar, Ajoy Prasad Shetty, S. Rajasekaran“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-4-15

Preventive Effect on the Vertebral Collapse Progression and Potential in Reducing the Need for Surgery in Conservative
Treatment with Initial 2-Week Bed Rest for Osteoporotic Vertebral Fracture
61
Toru Funayama, Masaki Tatsumura, Kengo Fujii, Shun Okuwaki, Yosuke Shibao, Fumihiko Eto, Katsuya Nagashima,
Kousei Miura, Hiroshi Noguchi, Kosuke Sato, Mamoru Kono, Tomoyuki Asada, Hiroshi Takahashi, Masao Koda,
Masashi Yamazaki

PS-FP-4-16

Effect of Teriparatide in Vertebroplasty with Posterior Spinal Fusion for Osteoporotic Thoracolumbar Vertebral Fracture
62
Yohei Shibuya, Kei Watanabe, Masayuki Ohashi, Hideki Tashi, Tatsuo Makino

PS-FP-4-17

Comparison of Balloon Kyphoplasty and Conservative Treatment for Osteoporotic Vertebral Fractures in Patients with
Dementia
62
Atsushi Hasegawa, Yoshiaki Kinoshita, Kazumasa Konishi, Takumi Takeuchi, Hideto Sano, Masahito Takahashi,
Shoichi Ichimura, Naobumi Hosogane

PS-FP-4-18

Is Fusion Necessary in AO Type C Injuries of the Thoracolumbar Spine?

PS-FP-4-19

Alteration of Global and Regional Sagittal Alignment after Correction Surgery for Focal Kyphosis at The Thoracolumbar Junction
63

63

Chandhan Murugan, Rishi Kanna, Ajoy Shetty, Rajasekaran Shanmuganathan

Po Hao Huang, Chih Wei Chen, Ming Hsiao Hu, Shu Hua Yang

PS-FP-4-20

The Osteoporosis-Induced Vertebral Fracture like the Traumatic Burst Fracture (AO–B2) Shows the Prolonged Instability and the Progress Local Kyphosis
64
Ryutaro Kozuma, Akihisa Yamashita

PS-FP-5-1

Optimizing the Brace-Weaning Criteria in Adolescent Idiopathic Scoliosis: The Role of Utilizing the New Sanders 7b
Staging
65
Jason Pui Yin Cheung, Prudence Wing Hang Cheung

PS-FP-5-2

Computed Tomography Analysis of Sacropelvic Parameters in Patients with and without L5 Spondylolysis

PS-FP-5-4

Does the Segmental Flexibility Assessed by Fulcrum-bending Radiograph Correlate with Postoperative Each Cobb
Angle in Adolescent Idiopathic Scoliosis?
66

65

Joseph F. Baker

Sachiko Kawasaki, Hideki Shigematsu, Masato Tanaka, Akinori Okuda, Keisuke Masuda, Yuma Suga, Yusuke Yamamoto,
Yasuhito Tanaka

PS-FP-5-6

Postoperative Coronal Imbalance Following Selective Thoracolumbar-Lumbar Fusion in Lenke 5C Adolescent Idiopathic Scoliosis
66
Akira Matsumura, Takashi Namikawa, Minori Kato, Yusuke Hori, Masayoshi Iwamae, Ryosuke Yanai, Daichi Takahashi,
Hiroaki Nakamura

PS-FP-5-7

Preliminary Report of Surgical Outcomes of the Relatively Short Fusion (L2-Pelvis Fixation) for the Adult Spinal Deformity Patients
67
Akira Matsumura, Takashi Namikawa, Minori Kato, Ryosuke Yanai, Daichi Takahashi, Hiroaki Nakamura

PS-FP-5-10

Factors Influencing Postoperative Disc Angle in Lenke Type 5C Adolescent Idiopathic Scoliosis

PS-FP-5-11

Prevalence and Risk Factors for Subjacent Disc Wedging after Corrective Fusion Surgery in Lenke Type 5C Curve Patients
68

68

Satoru Demura, Kota Watanabe, Teppei Suzuki, Toshiaki Kotani, Takuya Yamamoto, Koki Uno, Noriaki Kawakami

Tomohiro Banno, Yu Yamato, Hiroki Oba, Tetsuro Ohba, Tomohiko Hasegawa, Go Yoshida, Hideyuki Arima, Shin Oe,
Yuki Mihara, Jun Takahashi, Hirotaka Haro, Yukihiro Matsuyama

PS-FP-5-12

Global Imbalances in the Lower Lumbar Are Risk Factors for Revision Surgeries in Postoperative Adolescent Idiopathic
Scoliosis Patients: Clinical Analyses with a Median Follow-up of 17.4 Years
69
Tsunehiko Konomi, Takashi Asazuma, Shinjiro Kaneko, Yoshihide Yanai, Toshiki Ohkubo, Mitsuru Furukawa, Yoshiyuki Yato

“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-5-13

The Role of Routine Preoperative Echocardiogram in Adolescent Idiopathic Scoliosis Patients Undergoing Deformity
Corrective Surgery
69
Ahmed M. A. Hassan, Siddharth Shah, Mohammed Patel

PS-FP-5-14

The Role of Preoperative Somatosensory Evoked Potential in Patients Undergoing Adolescent Idiopathic Scoliosis Corrective Surgery
70
Ahmed M. A. Hassan, Siddharth Shah, Mohammed Patel

PS-FP-5-15

Computed Tomography Study of the Relationship between Pelvic Incidence and Osseous Contribution to Lumbar Lordosis in Children
70
Joseph F. Baker

PS-FP-5-16

Improvement of the Patient Demographics, Radiographic Index and Surgical Invasiveness for Mechanical Failure(PRISM) with Prevention Procedures of Mechanical Failures in Adult Spinal Deformity Surgery
71
Mitsuru Yagi, Satoshi Suzuki, Eijiro Okada, Satoshi Nori, Osahiko Tsuji, Narihito Nagoshi, Masaya Nakamura,Morio Matsumoto, Kota Watanabe

PS-FP-5-18

The Effect of Lumbosacral Fusion on Scoliotic Curves in Young Patients with Co-existing Spondylolysis/Spondylolisthesis: A Retrospective Cross-Sectional Study of Clinical, Functional and Radiological Outcomes
71
Dilip Chand Raja Soundararajan, Ajoy Prasad Shetty, Rishi Mugesh Kanna, Rajasekaran Shanmuganathan

PS-FP-5-20

Change of Hip and Knee Joint after Surgery for Adult Spinal Deformity and Correlation between Those and Full Body
Sagittal Parameters
72
Joonghyun Ahn, Yong-Chan Kim, Ki-Tack Kim, Kee-Yong Ha, Qiang Luo, Seungnam Ko, Sung-Min Kim, Hyungon Gwak

PS-FP-5-21

Comparison of 5-Year Surgical Results between Anterior Surgery and Posterior Surgery in Type 5 Adolescent Idiopathic Scoliosis: Stratification with Level of Upper and Lower End Vertebra
73
Kota Watanabe, Takahiro Iida, Kazuyuki Matsumoto, Hiroki Hayami, Satoru Ozeki, Mitsuru Yagi, Satoshi Suzuki,
Masaya Nakamura, Morio Matsumoto

PS-FP-5-25

Do Different Upper Instrumented Vertebra Anchors Impact the Incidence of Proximal Junctional Kyphosis in Adult
Spinal Deformity Surgery?
73
Ryosuke Yanai, Akira Matsumura, Tkashi Namikawa, Daichi Takahashi, Hiroaki Nakamura

PS-FP-5-26

Short-Segmental Spinal Fusion for Chronic Low Back Pain with Bone Marrow Edema Adjacent to the Vertebral Endplate74
Toshio Nakamae, Naosuke Kamei, Yoshinori Fujimoto, Kiyotaka Yamada, Yuji Tsuchikawa, Taiki Morisako, Takahiro Harada,
Toshiaki Maruyama, Nobuo Adachi

PS-FP-5-28

Evaluation of Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis Lenke Type 5 Using EOS Radiography

PS-FP-5-29

Can Anatomic Reduction with Monosegmental Fusion in High-Grade L5 Spondylolisthesis Restore Global Spinopelvic
Alignment?
75

75

Bin Xiao, Kai Yan, Yanbin Zhang, Jile Jiang, Yonggang Xing, Bo Liu, Wei Tian

Hiroshi Moridaira, Satoshi Inami, Daisaku Takeuchi, Haruki Ueda, Hiromichi Aoki, Takuya Iimura, Hiroshi Taneichi

PS-FP-5-31

Fat Infiltration in Back Muscles and Gluteus Maximus Muscle Is Significantly Related to Deterioration of Spino-Pelvic
Sagittal Balance During Gait
76
Kousei Miura, Tomoyuki Asada, Hideki Kadone, Kosuke Sato, Mamoru Kono, Fumihiko Eto, Yosuke Shibao, Kentaro Mataki,
Hiroshi Noguchi, Hiroshi Takahashi, Toru Funayama, Masao Koda, Masashi Yamazaki

PS-FP-5-32

Single Level Posterior Lumbar Interbody Fusion Can Improve Global Sagittal Alignment in a Patient with Severe Dysplastic Spondylolisthesis
77
Kazuki Takeda, Eijiro Okada, Satoshi Suzuki, Satoshi Nori, Osahiko Tsuji, Narihito Nagoshi, Mitsuru Yagi, Nobuyuki Fujita,
Masaya Nakamura, Morio Matsumoto, Kota Watanabe“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-5-38

Comparison of Radiographic Outcomes between Traditional Growing Rod and Shilla Graduates by a Single Surgeon		
77
Teppei Suzuki, Koki Uno, Masaaki Ito, Kenichiro Kakutani

PS-FP-5-42

Surgical Outcome of Spinal Fusion for Osteogenesis Imperfecta with Scoliosis

PS-FP-5-44

Development of a Prediction Model for Postoperative Lumbar Cobb Angle Following Selective Thoracic Fusion in Patients with Adolescent Idiopathic Scoliosis
78

78

Masaaki Ito, Koki Uno, Teppei Suzuki

I-Hsin Chen, Chih-Wei Chen, Ming-Hsiao Hu, Po-Liang Lai, Shu-Hua Yang

PS-FP-5-45

Does Osteoporosis Affect the Postoperative Course of Adult Spinal Deformity Surgery?

PS-FP-5-47

Predicting the Natural Course of Hemivertebra in Early Childhood: Clinical Significance of Anteroposterior Discordance Based on Three-Dimensional Analysis
80

79

Kenta Kurosu, Go Yoshida, Tomohiko Hasegawa, Yu Yamato, Tomohiro Banno, Hideyuki Arima, Shin Oe, Yuki Mihara,
Hiroki Ushirozako, Tomohiro Yamada, Koichiro Ide, Yuh Watanabe, Keiichi Nakai, Yukihiro Matsuyama

Sam Yeol Chang, Hyoungmin Kim, Bong-Soon Chang, Choon-Ki Lee

PS-FP-5-51

Which Is More Predictive Value for Mechanical Complications: Fixed Thoracolumbar Alignment versus Dynamic
Global Balance Parameter
80
Kwang-Ryeol Kim, Sung-Hyun Noh, Yoon Ha, Kyung-Hyun Kim

PS-FP-5-52

Mid-Term Health-Related Quality of Life and Its Related Factors Following Adult Spinal Deformity Surgery: A Minimum 5-Year Followup Case Series
81
Masayoshi Iwamae, Akira Matsumura, Yusuke Hori, Ryosuke Yanai, Takashi Namikawa, Minori Kato, Hiroaki Nakamura

PS-FP-5-53

Predicting the Progression of Thoracolumbar Kyphosis in Achondroplasia Patients after Walking Age: Generalized Estimating Equation Analysis
82
Su Jung Mok, Hyoungmin Kim, Sam Yeol Chang, Sung Cheol Park, Bong-Soon Chang, Tae-Joon Cho, Jung Min Ko

PS-FP-5-54

Oblique Lumbar Interbody Fusion Combined with Anterior Screws Fixation for Surgical Treatment of Lumbar Degenerative Scoliosis
82
Yutong Gu

PS-FP-5-55

Propensity Score-Matched Analysis to Assess the Risk Factor of Postoperative Proximal Junctional Fracture in Adult
Spinal Deformity Surgery
83
Junya Katayanagi, Takahiro Iida, Atsuki Hayamizu, Kazuyuki Matsumoto, Hirokazu Furukawa, Hiroki Konuma,
Tsukasa Yanase, Tetsuya Jinno

PS-FP-5-56

Clinical Outcomes of Extensive Corrective Fusion Surgery from Thoracic Spine to Pelvis for Adult Spinal Deformity at
5 Years Postoperatively
83
Hideyuki Arima, Tomohiko Hasegawa, Yu Yamato, Go Yoshida, Tomohiro Banno, Shin Oe, Yuki Mihara, Hiroki Ushirozako,
Tomohiro Yamada, Koichiro Ide, Yuh Watanabe, Keiichi Nakai, Kenta Kurosu, Yukihiro Matsuyama

PS-FP-5-59

Upper End Vertebra of Proximal Thoracic Curve at T1 is a Novel Risk Factor of Postoperative Shoulder Imbalance inType 2 Adolescent Idiopathic Scoliosis
84
Norihiro Isogai, Mitsuru Yagi, Nao Otomo, Yoshihiro Maeda, Satoshi Suzuki, Satoshi Nori, Osahiko Tsuji, Narihito Nagoshi,
Eijiro Okada, Nobuyuki Fujita, Masaya Nakamura, Morio Matsumoto, Kota Watanabe

PS-FP-5-60

A Novel Intraoperative Spino-Pelvic Parameter “Thoracic 10 Pelvic Angle” Can Predict Proximal Junctional Kyphosis
after Adult Spinal Deformity Surgery
85
Norihiro Isogai, Yutaka Sasao, Kenshi Daimon, Shigeto Ebata, Haruki Funao, Ken Ishii

PS-FP-5-62

Differences in Natural Walking for Elderlies by the Degree of the Low Back Pain: Gait Analysis with KINECT

85

Yuh Watanabe, Yu Yamato, Tomohiko Hasegawa, Go Yoshida, Tomohiro Banno, Hideyuki Arima, Yuki Mihara, Shin Oe,
Hiroki Ushirozako, Tomohiro Yamada, Koichiro Ide, Keiichi Nakai, Kenta Kurosu, Yuya Takahashi, Haruo Niwa,
Hironobu Hoshino, Yukihiro Matsuyama“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-5-63

Clinical Relationships between Spinopelvic Parameters and Lumbar Disc Degeneration in Different Disc Regions

86

PS-FP-5-64

Three-Rod Correction Technique for Severe Neuromuscular Scoliosis

87

PS-FP-5-66

Influence of Pelvic Obliquity on Postoperative Coronal Radiographic Parameters in Patients with Lenke Type 5 Adolescent Idiopathic Scoliosis at Minimum 5-Year Follow-up
87

Kazuhiro Inomata, Yoichi Iizuka, Eiji Takasawa, Tokue Mieda, Sho Ishiwata, Yohei Kakuta, Akira Honda, Yusuke Tomomatsu,
Shunsuke Ito, Hirotaka Chikuda
Toru Yamaguchi, Haruhisa Yanagida, Kazuyuki Takamura, Tomoyuki Nakamura

Takahito Iga, Satoshi Suzuki, Satoshi Nori, Osahiko Tsuji, Narihito Nagoshi, Eijiro Okada, Mitsuru Yagi, Masaya Nakamura,Morio Matsumoto, Kota Watanabe

PS-FP-5-67

Can Bone Improvement after 2-Year Calcium+Vitamin-D Supplementation Be Maintained in Idiopathic Scoliosis after
4-Year of Treatment Discontinuation: A Prospective Randomized Double-Blinded Placebo-Controlled Trial
88
Tsz Ping Lam, Guangpu Yang, Henry Pang, Wayne Yw Lee, Alec Lik-Hang Hung, Jack Chun-Yiu Cheng

PS-FP-5-72

The Impact of Growing Rod Surgery for Early Onset Scoliosis on the Cervical Spine Sagittal Alignment

88

PS-FP-5-73

Scoliosis in Osteogenesis Imperfecta: Quality of Life and Surgical Impact

89

PS-FP-5-74

Machine Learning for Predicting Mechanical Complication after Adult Spinal Deformity Surgery

90

PS-FP-5-75

Defining Spino-Pelvic Alignment in Adult Population Over 60 Years Old: Prospective Analysis of 214 Volunteers

91

PS-FP-5-76

Which Domain or Factors Of 36-Item Short Form Health Survey Impact on Patient Satisfaction after Adult Spinal Deformity Correction Surgery?
91

Shuhei Ito, Satoshi Suzuki, Satoshi Nori, Osahiko Tsuji, Narihito Nagoshi, Eijiro Okada, Mitsuru Yagi, Masaya Nakamura,Morio Matsumoto, Kota Watanabe
Janus S. H. Wong, Jason P. Y. Cheung, Prudence W. H. Cheung, Ya Peng Zhou, Michael K. T. To
Sung Hyun Noh, Yoon Ha, Kyung Hyun Kim

Sung Hyun Noh, Kyung Hyun Kim, Yoon Ha

Hyun Jun Jang, Jeong Yoon Park, Dong Kyu Chin, Young Seol Yoon, Keun Su Kim, Yong Eun Cho, Kyung Hyun Kim

PS-FP-5-80

Preoperative Distraction of Severe Caries Kyphotic Spine Deformities with Modified Halo-Pelvic Distraction Assembly		
93
Amer Aziz, Muhammad Saad Ilyas

PS-FP-5-82

Which Health-Related Quality of Life Assessment Tool, Patient-Reported Outcomes Measurement Information System, Revised Scoliosis Research Society-22, or Oswestry Disability Index, Is More Sensitive in Assessing Outcomes ofPrimary versus Revision Adult Spinal Deformity Surgery?
92
Tsung-Cheng Yin, Munish C. Gupta

PS-FP-5-83

Experiences of Early Air Travel with Pneumothorax after Anterior Spinal Surgery: A Report of Three Cases

PS-FP-5-84

Radiological Assessment of Pre- and Postoperative Shoulder Balance Following Posterior Spinal Fusion for Lenke 2
Adolescent Idiopathic Scoliosis
93

93

Amy Yoke Foong Wong, Choong Hoon Foo, Nur Aida Binti Faruk Senan, Mohamad Zaki Bin Hj Mohd Amin,
Chung Chek Wong

Takashi Namikawa, Akira Matsumura, Minori Kato, Hiroaki Nakamura

PS-FP-5-85

Surgical Outcomes in Syndromic Scoliosis with Neurofibromatosis

94

PS-FP-5-86

Risk Factors for Lateral Translation in Adult Idiopathic Adolescent Scoliosis with thoracolumbar/Lumbar Curves

95

PS-FP-5-87

Predictive Factors for Nighttime Bracing Treatment Outcome in Adolescent Idiopathic Scoliosis

95

Tatsuo Kato, Koki Uno, Teppei Suzuki, Masaaki Ito, Kohei Kuroshima

Toshiaki Kotani, Tsuyoshi Sakuma, Yasushi Iijima, Keita Nakayama, Yasuchika Aoki, Kotaro Sakashita, Takahiro Sunami,
Kosuke Sato, Tomoyuki Asada, Tsutomu Akazawa, Kazuhide Inage, Yasuhiro Shiga, Shohei Minami, Seiji Ohtori
Naoya Taki, Hideaki Watanabe, Ichiro Kikkawa“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-5-89

Predictors for Total Blood Loss During Posterior Spinal Fusion Surgery for Idiopathic Scoliosis

PS-FP-5-91

Analgesic and Opioid Medication Profile of European Adult Spinal Deformity Patients: Minimum 5 Years Follow-up
Study
96

96

Eiki Shirasawa, Wataru Saito, Masayuki Miyagi, Yusuke Mimura, Shinsuke Ikeda, Yuji Yokozeki, Akiyoshi Kuroda,
Takayuki Imura, Toshiyuki Nakazawa, Gen Inoue, Masashi Takaso

Caglar Yilgor, Altug Yucekul, Tais Zulemyan, Yasemin Yavuz, Anouar Bourghli, Louis Boissiere, Ibrahim Obeid, Javier Pizones,
Frank Kleinstueck, Fransisco J. S. Perez-Grueso, Ferran Pellisé, Ahmet Alanay, European Spine Study Group

PS-FP-5-92

Relationship between Adult Spinal Deformity Surgery and Employment, Sick Leaves, Return to Work and Early Retirement: Minimum 5-Year Follow-up Study
97
Caglar Yilgor, Altug Yucekul, Tais Zulemyan, Yasemin Yavuz, Javier Pizones, Ibrahim Obeid, Frank Kleinstueck,
Fransisco J. S. Perez-Grueso, Ferran Pellisé, Ahmet Alanay, European Spine Study Group

PS-FP-5-93

Complications and Analysis of Risk Factors of Spinal Surgery in Ankylosing Spondylitis: Single Center Case Series of 50
Patients
98
Kushal Ramesh Gohil, Saumyajit Basu

PS-FP-5-94

Impact of Endplate Injury during Corrective Surgery Using Oblique Lumbar Interbody Fusion in Adult Spinal Deformity
99
Gen Inoue, Wataru Saito, Masayuki Miyagi, Takayuki Imura, Eiki Shirasawa, Yusuke Mimura, Akiyoshi Kuroda, Yuji Yokozeki,
Toshiyuki Nakazawa, Masashi Takaso

PS-FP-5-95

Single-Stage Posterior Surgical Treatment for Grade V Spondylolisthesis of L5 in a Patient with Neurofibromatosis Type
1 and Dural Meningocele: A Case Report
99
Canhua Ye, Chunguang Duan, Huiren Tao

PS-FP-5-96

Handgrip Strength Potentially Predicts Curve Progression in Adolescent Idiopathic Scoliosis Girls

PS-FP-5-97

Outcome of Posterior Vertebral Column Resection in Neglected Rigid Congenital Scoliosis and Kyphoscoliosis: Our
Experience and Review of Literature
101

100

Rufina Wing Lum Lau, Ka Yee Cheuk, Vivian Wing Yin Hung, Fiona Wai Ping Yu, Elisa Man Shan Tam, Lyn Lee Ning Wong,
Jiajun Zhang, Franco Tsz Fung Cheung, Wing Sze Yu, Wayne Yuk Wai Lee, Jack Chun Yiu Cheng, Tsz Ping Lam

Arif Mohammad, Sattar Abdul, Zahid Mohammad, Sameer Kabir, Ihsan Ullah, Asmat Ullah

PS-FP-5-98

Clinical and Radiological Outcomes in the Patients of Parkinson’s Disease Undergoing Instrumented Lumbar Spine
Surgery for Spinal Disorders
101
Ashish Gupta, Saumyajit Basu

PS-FP-5-99

Evaluating Biomechanics of the Novel Active Apex Correction Technique Using a Patient-Specific Finite Element Approach with 6-Month Follow-up
102
Daksh Jayaswal, Alaaeldin Ahmad, Aakash Agarwal, Manoj Kodigudla, Amey Kelkar, Vijay Goel

PS-FP-5-100 Usefulness of Percutaneous Pedicle Screws for Minimizing the Risk of Proximal Junctional Kyphosis after Adult Spinal
Deformity Correction Surgery
103
Tomohisa Harada, Sei Terayama, Yasuo Ohori, Satoshi Makio, Hidenobu Ishibashi, Ryota Takatori, Kenji Takahashi

PS-FP-5-103 Optimal Position to Insert the Sacral-Alar-Iliac Screw with the Analysis of Computed Tomography View and the
Torque of Inserting It
103
Fumihiro Miyaguchi

PS-FP-5-106 Is It Really Less Invasive?: Systemic Effects of Anterior-Posterior Lumbar Surgery with Oblique Lateral Interbody Fusion by Nutrition Support Team Perspective
104
Momo Irie, Muneaki Masuda, Osamu Kawano, Takeshi Maeda“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-5-108 Distribution of Spinal Sagittal Alignment Based on Hierarchical Clustering

104

Yusuke Hori, Hiromitsu Toyoda, Shinji Takahashi, Masatoshi Hoshino, Shoichiro Ohyama, Hidetomi Terai, Akinobu Suzuki,
Tadao Tsujio, Sho Dohzono, Minori Kato, Akira Matsumura, Takashi Namikawa, Kazuhide Inage, Sumihisa Orita,
Masayuki Miyagi, Gen Inoue, Seiji Ohtori, Masashi Takaso, Hiroaki Nakamura

PS-FP-5-109 The Analysis of Progression of the Pfirrmann’s Grade in Distal Unfused Segments in Postoperative Adolescent Idiopathic Scoliosis: A Long-Term Follow-up Magnetic Resonance Imaging Based Study
105
Guna K. Pratheep, Sri Vijay Anand, Rajasekaran Shanmuganathan, Ajoy Prasad Shetty, Rishi Mugesh Kanna

PS-FP-5-110 Characteristics of Pedicle Screw Misplacement Using Freehand Technique in Degenerative Scoliosis Surgery

105

Tomohiro Yamada, Tomohiko Hasegawa, Yu Yamato, Go Yoshida, Tomohiro Banno, Hideyuki Arima, Shin Oe, Yuki Mihara,
Hiroki Ushirozako, Koichiro Ide, Yuh Watanabe, Keiichi Nakai, Kenta Kurosu, Yukihiro Matsuyama

PS-FP-5-113 Increased C7 Tilt Is Associated with Higher Risk of Shoulder Imbalance in Adolescent Idiopathic Scoliosis Patients Receiving Posterior Spinal Fusion
106
Juiyo Hsu, Chih-Wei Chen, Ming-Hsiao Hu, Po-Liang Lai, Shu-Hua Yang

PS-FP-6-1
PS-FP-6-2
PS-FP-6-4
PS-FP-6-6

PS-FP-6-7

Computed Tomography Based Intraoperative Navigation for Spine Tumors: Perspectives in Surgical Margin

107

Spinal Extra-Osseous Chordoma Mimicking as Herniated Intervertebral Disc in the Lumbar Spine

107

Perioperative Complications of Total En Bloc Spondylectomy for Spinal Tumors

108Long-Term Outcomes of Spinal Meningioma Resection with Outer Layer of Dura Preservation Technique

108

Young-Hoon Kim, Sang-Il Kim, Hun-Chul Kim, Hyung-Youl Park

Kang Kai Lim, Zulkefli Atan, Manoharan Krishnan, Mohamad Azhari Omar, Zulrushdi Md Yusof

Satoru Demura, Satoshi Kato, Kazuya Shinmura, Noriaki Yokogawa, Takaki Shimizu, Makoto Handa, Ryohei Annen,
Motoya Kobayashi, Yohei Yamada, Hideki Murakami, Norio Kawahara, Hiroyuki Tsuchiya
Hirokazu Saiwai, Seiji Okada, Mitsumasa Hayashida, Katsumi Harimaya, Yoshihiro Matsumoto, Ken-ichi Kawaguchi,
Akinobu Matsushita, Kei-ichiro Iida, Kazu Kobayakawa, Kazuya Yokota, Takeshi Maeda, Kuniyoshi Tsuchiya,
Takeshi Arizono, Taichi Saito, Kazutoshi Nakaie, Yukihide Iwamoto, Yasuharu Nakashima

Prognostic Factors for Short-Term versus Long-Term Readmission-Free Survival after Metastatic Spine Tumor Surgery
109
Naresh Kumar, Andrew Thomas, Liang Shen, Sarah Tang, Sridharan Ramakrishnan, Sirisha Madhu

PS-FP-6-8

Clinical Results of Carbon-Ion Radiotherapy with Separation Surgery for Primary Spine/Paraspinal Sarcoma

110

PS-FP-6-10

The Surgical Strategies for Dumbbell-Shaped Tumors of the Upper Cervical Spine

110

PS-FP-6-11

Surgical Outcomes of Spinal Cord Tumor in Elderly Patients Using the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire
111

Yoshihiro Matsumoto, Kei-ichiro Iida, Hirokazu Saiwai, Makoto Endo, Toshifumi Fujiwara, Ken-ichi Kawaguchi,
Yasuharu Nakashima
Hao Zhang, Wei Ya Hu

Shuhei Ito Narihito Nagoshi, Osahiko Tsuji, Satoshi Nori, Satoshi Suzuki, Eijiro Okada, Mitsuru Yagi, Morio Matsumoto, Masaya Nakamura, Kota Watanabe

PS-FP-6-12

A Method for Predicting the Location of Dural Attachment of Spinal Meningioma: Tumor Attachment Angle

111

PS-FP-6-13

Usefulness of Artificial Cerebrospinal Fluid Replacement in Intradural Surgical Procedure

112

PS-FP-6-14

The Radiographic Characters and Surgical Outcomes of Spinal Meningioma Who Grade 1

113

Kazu Kobayakawa, Takeshi Maeda, Osamu Kawano, Hiroaki Sakai, Muneaki Masuda, Yuichiro Morishita, Tetsuo Hayashi,
Kensuke Kubota, Kazuya Yokota, Hironari Kaneyama,Hirokazu Saiwai, Keiichiro Iida, Akinobu Matsushita,
Kenichi Kawaguchi, Yoshihiro Matsumoto, Yasuharu Nakashima
Muneaki Masuda, Takeshi Maeda, Osamu Kawano

Tomohiko Hasegawa, Yu Yamato, Go Yoshida, Sho Kobayashi, Tatsuya Yasuda, Tomohiro Banno, Hideyuki Arima, Shin Oe,
Yuki Mihara, Hiroki Ushirozako, Yukihiro Matsuyama“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-6-16

The Utility of Minimal Access and Separation Surgery in the Management of Metastatic Spine Disease

PS-FP-6-18

Do aggressive Vertebral Hemangiomas Warrant Aggressive Surgery?: Inferences from a Retrospective Surgical Cohortof 23 Patients
114

113

Jiong Hao Tan, Andrew Cherian Thomas, Yong Hao Joel Tan, Hwee Weng Dennis Hey, Naresh Kumar

Guna K. Pratheep, Sri Vijay Anand, Rajasekaran Shanmuganathan, Ajoy Prasad Shetty, Rishi Mugesh Kanna

PS-FP-7-2
PS-FP-7-6

Micro-organisms and Outcome of Spinal Infections: A Report of 48 Cases

115

Quang Minh Luong, Duong Van Pham, Hung Dinh Nguyen

A Validated Score for Evaluating Spinal Instability to Assess Surgical Candidacy in Active Spinal Tuberculosis: An
Evidence-Based Approach and Multinational Expert Consensus Study
115
Dilip Chand Raja Soundararajan, S. Rajasekaran, Ajoy Prasad Shetty, Rishi Mugesh Kanna

PS-FP-7-7

Clinical, Radiological and Microbial Profile of Pyogenic Spondylodiscitis: Single-Center Data Analysis of 48 Patients		
116
Dheeraj Manikanta Maddali, Saumyajit Basu

PS-FP-7-8

Treatment Results of Percutaneous Posterior Lumbar Pelvic Fusion for Lower Lumbar Purulent/Tuberculous Discitis		
116
Yuji Kasukawa, Naohisa Miyakoshi, Michio Hongo, Yoshinori Ishikawa, Daisuke Kudo, Yoichi Shimada

PS-FP-7-9

Trends in Infectious Spondylitis from 2000 to 2020

117

PS-FP-7-10

Status and Trends of Causative Bacteria of Surgical Site Infection in Spinal Surgery: A Study on 6,411 Cases

118

PS-FP-7-11

Gene Xpert/MTB RIF Assay for Spinal Tuberculosis

118

PS-FP-7-12

Does Forced-Air Warming Increase Surgical Site Infections in Spine Surgery? A Propensity Score-Matched Analysis		119

Shinji Tanishima, Tokumitsu Mihara, Chikako Taked, Masaki Yoshida, Hideki Nagashima
Takahito Iga, Satoshi Suzuki, Satoshi Nori, Osahiko Tsuji, Narihito Nagoshi, Eijiro Okada, Mitsuru Yagi, Masaya Nakamura,Morio Matsumoto, Kota Watanabe
Siddharth Aiyer, Vijay Karthek, Pramod Bhilare, Shailesh Hadgaonkar, Ajay Kothari, Ashok Shyam, Parag Sancheti

Kyoichi Handa, Haruo Kanno, Shigetsune Matsuya, Kohei Takahashi, Ko Hashimoto, Toshimi Aizawa

PS-FP-7-13“Spine Surgery Checklist” a Step Towards Perfection Through Protocols

119

PS-FP-7-14

Analysis of Clinical Features Regarding Concomitant Spinal and Non-spinal Osteoarticular Infections

120

PS-FP-7-15

Consecutive Occurrence of Septic Arthritis and Pyogenic Spondylitis in Two Patients

120

PS-FP-7-16

A Case of Glossopharyngeal and Hypoglossal Nerve Paralysis Secondary to Pyogenic Cervical Facet Joint Arthritis 121

PS-FP-7-17

Clinical Significance of Comprehensive Medicine for the Treatment of Pyogenic Spondylitis in the Elderly

122

PS-FP-7-19

Tuberculous Osteomyelitis of the Ischium: A Case Report and Review of Literature

122

PS-FP-7-21

Characterization of Biofilms in Explanted Pedicle Screws Retrieved from Aseptic Pseudarthrosis Cases

123

Jwalant Y. Patel, Arvind G. Kulkarni

Ryunosuke Fukushi, Satoshi Kawaguchi, Toshihiko Yamashita
Ryunosuke Fukushi, Satoshi Kawaguchi, Toshihiko Yamashita
Ryunosuke Fukushi, Izaya Ogon, Toshihiko Yamashita

Hidekazu Yoshizaki, Tzong-Jing Victor Wang, Manabu Ito

Chandhan Murugan, Ajoy Shetty, Rajasekaran Shanmuganathan

Daksh Jayaswal, Aakash Agarwal, Megan Mooney, Ashish Agarwal, Arvind Jayaswal, Amey Kelkar, Gayane Saakyan,
Vijay Goel, Vithal Shendge, Hossein Elgafy“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-7-22

How Does the Absence or Presence of Pedicle Screw Guard Effect Bacterial Contamination at the Screw-Bone Interface
during Spinal Fusion: A Multicenter Study
123
Daksh Jayaswal, Aakash Agarwal, Boren Lin, Ashish Agarwal, Amey Kelkar, Gayane Saakyan, Hossein Elgafy, Vijay Goel,
Arvind Jayaswal, Christian Schultz, Anand Agarwal

PS-FP-7-23

Poor Nutritional Status and Chronic Kidney Disease Might Be Risk Factors in Elderly Patients with Pyogenic Spondylitis
124
Erina Yamada, Toshihiro Imamura, Yukihide Iwamoto

PS-FP-7-24

Evaluating Reprocessed Pedicle Screws: Characterization of Contaminants and Efficiency of the Process

PS-FP-7-26

All-Posterior Approach in Surgical Management of Thoracolumbar Tuberculosis: A Prospective Randomized Study
Comparing Posterior-Only Stabilization versus Global Reconstruction
125

125

Daksh Jayaswal, Aakash Agarwal, Amey Kelkar, Ashish Agarwal, Gayane Saakyan, Arvind Jayaswal, Anand Agarwal

Rohit Akshay Kavishwar, Ajoy Prasad Shetty, S. Rajsekeran

PS-FP-7-27

Development of Tuberculosis Spine Instability Score (TSIS): An Evidence-Based and Expert Consensus-Based Content
Validation Study Among Spine Surgeons126
Kaustubh Ahuja, Syed Ifthekar, Samarth Mittal, Gagandeep Yadav, Pankaj Kandwal

PS-FP-8-1

The Characteristics of the Young Patients with Cervical Ossification of the Posterior Longitudinal Ligament of theSpine: A Multicenter Cross-Sectional Study
126
Kanji Mori, Toshitaka Yoshii, Takashi Hirai, Jun Hashimoto, Narihito Nagoshi, Kazuhiro Takeuchi, Keiichi Katsumi,
Satoshi Maki, Masaya Nakamura, Morio Matsumoto, Atsushi Okawa, Yoshiharu Kawaguchi, JOSL Members

PS-FP-8-2

Reduction and Fusion of Thoracic Ossification of the Posterior Longitudinal Ligament after Posterior Decompression
with Instrumented Fixation by Pedicle Screw Insertion into All Ossified Vertebrae
127
Osamu Kawano, Takeshi Maeda, Hiroaki Sakai, Muneaki Masuda, Yuichiro Morishita, Tetsuo Hayashi, Kensuke Kubota,
Kazu Kobayakawa, Kazuya Yokota, Hironari Kaneyama

PS-FP-8-3

Does Diabetes Affect the Surgical Outcomes in Cases with Cervical Ossification of the Posterior Longitudinal Ligament? A Multicenter Study from Asia Pacific Spine Study Group
128
Narihito Nagoshi, Kota Watanabe, Masaya Nakamura, Morio Matsumoto, Nan Li, Sai Ma, Da He, Wei Tian,
Hyeongseok Jeon, Jong Joo Lee, Keung Nyun Kim, Yoon Ha, Kenny Kwan, AKP Cheung

PS-FP-8-5

Comparison of Decompression Alone and Decompression Plus Fusion for Thoracic Myelopathy Due to Ossification of
the Ligamentum Flavum
128
Yuichi Ono, Naohisa Miyakoshi, Yuji Hatakeyama, Yoichi Shimada

PS-FP-8-7

Factors Having Significant Relationship with Postoperative Neck Pain Deterioration for Cervical Ossification of the
Posterior Longitudinal Ligament: Prospective Registry Study
129
Masao Koda, Toshitaka Yoshii, Satoru Egawa, Kenichiro Sakai, Yukihiro Nakagawa, Kanichiro Wada, Keiichi Katsumi,
Atsushi Kimura, Yukitaka Nagamoto, Yasushi Oshima, Masahiko Takahata, Kanji Mori, Takashi Kaito, Sho Kobayashi,
Satoshi Kato, Shiro Imagama, Yoshiharu Kawaguchi, Morio Matsumoto, Atsushi Okawa, Masashi Yamazaki

PS-FP-8-8
PS-FP-9-3
PS-FP-9-4

Characteristics of Ossification of the Ligamentum Flavum of the Thoracic Spine

130

Posterior Spinal Fusion with Pedicle Screws for Atlantoaxial Instability in Children

130

Masatoshi Morimoto, Kazuya Kijima, Kiyoshi Yagi, Fumitake Tezuka, Kazuta Yamashita, Koichi Sairyo
Kohei Kuroshima, Koki Uno, Masaaki Ito, Teppei Suzuki

Biologic Agents Preserve the C-2 Pedicle in Patients with Rheumatoid Arthritis: A Comparative Imaging Study Using
Three-Dimensional Computed Tomography
131
Takuya Obo, Takashi Fujishiro, Masahiro Mizutani, Toma Yano, Sachio Hayama, Yoshiharu Nakaya, Atsushi Nakano,
Masashi Neo“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-9-5

Non-traumatic Atlantoaxial Rotatory Fixation in an Adult Patient Treated by a Closed Reduction under General Anesthesia in Chronic Phase
131

Norihiro Isogai, Kenshi Daimon, Yutaka Sasao, Shigeto Ebata, Haruki Funao, Ken Ishii

PS-FP-10-1

The Ipsilateral Epiphyseal and Central Endplate Hounsfield Units Accurately Predicts Intraoperative Endplate Violation
and Delayed Cage Subsidence with Oblique Lateral Interbody Fusion
132
Jason Pui Yin Cheung, Hao Wu, Teng Zhang, Zhi Shan, Xuyang Zhang, Junhui Liu, Shunwu Fan, Fengdong Zhao

PS-FP-10-3

A New Full Endoscopy System and Intradiscal Irrigator Combined with a Novel Annular Repair Device for the Treatment of Lumbar Disc Herniation
133
En Song, Ji Zheng Li, Yan Lin Li, You Qing Huang, Fan Bing Li, Xiao Feng Yuan, Xue Song Chen, En Bin Wang,
Xian Guang Yang, Yao Yu Xiang

PS-FP-10-4

A Novel Annular Repair Technique Combined with Platelet-Rich Plasma Intradiscal Injection: A New Serial Therapeutic Model for the Treatment of Lumbar Disc Herniation
134
En Song, Ji Zheng Li, Yan Lin Li, En Bin Wang, Fan Bing Li, You Qing Huang, Xiao Feng Yuan, Xue Song Chen,
Xian Guang Yang, Yao Yu Xiang

PS-FP-10-5

Overcorrection of Fractured Vertebrae Increases the Incidence of Adjacent Fractures After Balloon Kyphoplasty: A Retrospective Study
134
Keiichiro Iida, Hirokazu Saiwai, Akinobu Matsushita, Kenichi Kawaguchi, Yoshihiro Matsumoto, Yasuharu Nakashima

PS-FP-10-6

Pros and Cons of Full Endoscopic Surgery for Cervical Radiculopathy

135

PS-FP-10-7

Functional Outcomes of Loupe Assisted Discectomy in Patients with Lumber Disc Herniation

135

PS-FP-10-8

Indirect Neural Decompression by Transforaminal Lumbar Interbody Fusion Using Minimally Invasive Spine Surgery
for Lumbar Degenerative Spondylolisthesis: Comparison with Lateral Lumbar Interbody Fusion
136

Kuniyoshi Tsuchiya

Shehar Yar Abid, Muhammad Tahir Karim, Shahid Ali

Ichiro Torigoe, Yoshiyasu Arai, Kenichiro Sakai, Masaki Tomori, Kyohei Sakaki, Takuya Oyaizu, Keigo Hirai, Atsushi Okawa

PS-FP-10-9Transforaminal Full-Endoscopic Discectomy for the Patients with Down-Migrated Lumbar Disc Herniation under Local Anesthesia
137
Fumitake Tezuka, Kazuya Kishima, Kiyoshi Yagi, Kosuke Sugiura, Masatoshi Morimoto, Kazuta Yamashita, Koichi Sairyo

PS-FP-10-10 Transforaminal Full-Endoscopic Ventral Facetectomy: Mid-Term Results and Factors Associated with Fair/Poor Outcome
137
Kazuya Kishima, Kiyoshi Yagi, Keishi Maruo, Toshiya Tachibana, Masatoshi Morimoto, Fumitake Tezuka, Kazuta Yamashita,Toshinori Sakai, Toru Maeda, Koichi Sairyo

PS-FP-10-11 Unintentional Facet Fusion without Bone Grafting after Minimally Invasive Lumbar Interbody Fusion: A Retrospective
Study of Percutaneous Endoscopic Transforaminal Lumbar Interbody Fusion
138
Katsuhisa Yamada, Ken Nagahama, Yuichiro Abe, Masahiko Takahata, Norimasa Iwasaki

PS-FP-10-12 The Advantages of Revisional Transforaminal Full-Endoscopic Spine Surgery for Patients Underwent Posterior Spine
Surgery
138
Kiyoshi Yagi, Kosuke Sugiura, Makoto Takeuchi, Kazuya Kishima, Masatoshi Morimoto, Fumitake Tezuka, Kazuta Yamashita,
Yoichiro Takata, Toshinori Sakai, Toru Maeda, Koichi Sairyo

PS-FP-10-13 Risk Assessment of Abdominal and Retroperitoneal Organ Injuries Performing Transforaminal Full-Endoscopic Spine
Surgery
139
Kiyoshi Yagi, Kosuke Sugiura, Makoto Takeuchi, Kazuya Kishima, Masatoshi Morimoto, Fumitake Tezuka, Kazuta Yamashita,
Yoichiro Takata, Toshinori Sakai, Toru Maeda, Koichi Sairyo

PS-FP-10-14 Is Bipolar Release of Sternocleidomastoid Muscle Necessary for Neglected Congenital Muscular Torticollis?

140

Haruki Funao, Kenshi Daimon, Kento Yamanouchi, Tomoharu Tanaka, Norihiro Isogai, Yutaka Sasao, Shigeto Ebata, Ken Ishii“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-10-15 Usefulness and Problems of the Double Endplates Penetrating Screw Technique for Patients with Diffuse Idiopathic
Skeletal Hyperostosis
140
Takumi Takeuchi, Kenichiro Yamagishi, Masaaki Tsuji, Hideto Sano, Masato Takahashi, Shoichi Ichimura, Hitoshi Kouno,
Naobumi Hosogane

PS-FP-10-18 Percutaneous Transforaminal Endoscopic Surgery and Oblique Lateral Interbody Fusion with Self-Lock Cage for Surgical Treatment of L5 Spondylolisthesis
141
Yutong Gu

PS-FP-10-20 Full Endoscopic Posterior Cervical Foraminotomy under Lateral Decubitus Position with Local Anesthesia

142

Do Hyeong Lim, Michael Levitt, Dong Wha Heo, Byeong Cheol Rim

PS-FP-10-21 Three-Year Clinical Outcomes after Minimally Invasive Sacroiliac Joint Arthrodesis Using Triangular Implants in Japan:
A Pilot Study of Five Cases
142
Daisuke Kurosawa, Eiichi Murakami, Hiroaki Koga, Hiroshi Ozawa

PS-FP-10-24 Does Prophylactic Use of Topical Gelatin-Thrombin Matrix Sealant Affect Postoperative Drainage Volume and Hematoma Formation after Microendoscopic Spine Surgery?: A Randomized Controlled Trial
143
Masanari Takami, Hiroshi Hashizume, Yasutsugu Yukawa, Hiroshi Iwasaki, Shunji Tsutsui, Keiji Nagata, Ryo Taiji,
Shizumasa Murata, Takuhei Kozaki, Hiroshi Yamada

PS-FP-10-26 Comparison Between Clinical Outcomes of Simultaneous Parallel Anterior and Posterior Combined Lumbar Spine
Surgery Using Intraoperative Three-Dimensional Fluoroscopy-Based Navigation (SPAPS) and Minimally Invasive Posterior/Transforaminal Lumbar Interbody Fusion
144
Tomohiko Hirose, Hisanori Ikuma

PS-FP-10-27 Evaluation of Cement Leakage Using Computed Tomography after Balloon Kyphoplasty: Comparison between Patients Underwent within 4 Weeks and Patients Underwent after 4 Weeks
144
Hiroyuki Yasuda, Sadahiko Konishi, Masaki Terakawa, Hiroaki Nakamura

PS-FP-10-28 Decompression Procedure Using Unilateral Biportal Endoscopy for Thoracic Myelopathy Caused by Ossification of theLigamentum Flavum: A Technical Note and Preliminary Clinical Results
145
Seung-Hyun Choi, Sang-Kyu Son, Weon-Wook Park

PS-FP-10-29 Treatment Results of Minimally Invasive Lateral Lumbar Disc Herniated Disk in Our Department

145

Yoshikazu Yanagisawa, Masayoshi Ohga

PS-FP-10-31 Effectiveness of Foraminoplasty in Transforaminal Full-Endoscopic Discectomy for L5–S1 Disc Herniation Under Local Anesthesia
146
Takashi Inokuchi, Kazuta Yamashita, Fumitake Tezuka, Masatoshi Morimoto, Kazuya Kishima, Kiyoshi Yagi, Koichi Sairyo

PS-FP-10-32 Examination of Radiation Exposure in Lateral Lumbar Fusion Surgery Using Intraoperative Computed Tomography
Navigation
146
Satoshi Nomura, Akihiko Hiyama, Kosuke Sako, Masahiro Tanaka, Hiroyuki Kato, Daisuke Sakai, Masato Sato,
Masahiko Watanabe

PS-FP-10-33 The Efficacy of Epiduroscopic Adhesiolysis on Failed Back Surgery Syndrome147

Osman Yağız Atlı, Burhan Kurtulus, Hakan Aslan

PS-FP-10-34 Retrospective Study of Clinical and Radiological Outcomes of Minimally Invasive Transforaminal Lumbar Interbody
Fusion for High-Grade Spondylolisthesis: Series of 24 Patients with 2-Year Follow-up
147
Rajendra Sakhrekar, Vishal Peshattiwar, Mohan Gawande

PS-FP-11-1

Comparative Study for Navigated Drill and Navigated Probe for Cervical Pedicle Screw Insertion

148

Tomoyuki Takigawa, Takuya Morita, Yasuo Ito“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-11-2

Accuracy of Pedicle Screw Placement in Early Onset Scoliosis Using Intraoperative Computed Tomography and ImageGuided Navigation
149
Takuya Iimura, Hiroshi Moridaira, Satoshi Inami, Daisaku Takeuchi, Haruki Ueda, Hiromichi Aoki, Hiroshi Taneichi

PS-FP-11-3

C-Arm Free Lumbar Interbody Fusion

PS-FP-11-4

Robot-Assisted Minimally Invasive Transforaminal Lumbar Interbody Fusion in the Treatment of Lumbar Spondylolisthesis
150

149

Keisuke Nakano, Masaki Mori, Tomohiro Tominaga, Keiji Fujio, Toshimitsu Kawagishi, Toshitada Sawada, Toshihiro Tanaka,
Sunao Tanaka, Tohru Asari, Kyouta Ishibashi, Masanori Izeki

Guanyu Cui, Xiaoguang Han, Yajun Liu, Da He, Yuqing Sun, Bo Liu, Wei Tian

PS-FP-11-6

Comparison Between Machine-Vision Image Guided Surgery System and Robotic Guidance System for Pediatric Idiopathic Scoliosis Spine Surgery
151
Kevin Lim, Alyssa Toh, Nicole Lee

PS-FP-11-7

Safety of Pin Insertion Position for Iliac Reference Guide in Spinal Navigation

PS-FP-11-8

O Arm Navigation Assisted Minimally Invasive Transforaminal Lumbar Interbody Fusion for Degenerative Lumbar
Disease: Study of 83 Patients
152

151

Hiroaki Murakami, Yasushi Fujiwara, Ryo Ota, Shinji Kotaka, Hideki Manabe

Rajendra Sakhrekar, Vishal Peshattiwar, Mohan Gawande

PS-FP-12-1

Effectiveness of Nitinol in Motion-Preserving Stabilization of Lumbar Spine

PS-FP-12-2

Is There a Place for Surgical Repair in Adults with Spondylolysis or Grade I Spondylolisthesis?: A Systematic Review
and Treatment Algorithm
153

152

Arkadii Kazmin, Sergey Kolesov, Andrey Panteleev, Maxim Sazhnev

Naresh Kumar, Sirisha Madhu, Naveen Pandita, Miguel Ramos, Barry Wei Loong Tan, Jonathan Tan, Keith Lopez,
Dinesh Shree Kumar, Colum Patrick Nolan

PS-FP-12-3

A New Surgical Strategy for Type 1 Modic Change Using Transforaminal Full-Endoscopic Disc Cleaning Surgery 154

PS-FP-12-6

Does Vertebral Body Tethering Cause Disc and Facet Joint Degeneration? A Magnetic Resonance Imaging Study with
Minimum 2-Year Follow-up
154

Kazuya Kishima, Kiyoshi Yagi, Keishi Maruo, Toshiya Tachibana, Masatoshi Morimoto, Fumitake Tezuka, Kazuta Yamashita,Toshinori Sakai, Toru Maeda, Koichi Sairyo

Caglar Yilgor, Altug Yucekul, Burcu Akpunarli, Atahan Durbas, Tais Zulemyan, Irem Havlucu, Gokhan Ergene, Sahin Senay,
Pinar Yalinay Dikmen, Sule Turgut Balci, Ercan Karaarslan, Yasemin Yavuz, Ahmet Alanay

PS-FP-12-7

Is Thoracoscopic Vertebral Body Tethering a Pulmonary Function Declining or Improving Surgery?

155

PS-FP-12-8

Two- to 5-Year Follow-up Results After Thoracoscopic Vertebral Body Tethering: A Single Surgeon’S Experience156

PS-FP-12-9

Clinical and Radiographic Outcome at 7 Years of Follow-up after Cervical Total Disc Replacement

157

PS-FP-13-1

Fully-Automated Deep Learning Prediction of Spinal Deformity Alignment Irrespective of Image Quality Obtained via
Smartphone Photographs
157

Caglar Yilgor, Burcu Akpunarli, Altug Yucekul, Kadir Abul, Peri Kindan, Gokhan Ergene, Sahin Senay, Tais Zulemyan,
Yasemin Yavuz, Ahmet Alanay
Caglar Yilgor, Altug Yucekul, Kadir Abul, Ilkay Karaman, Atahan Durbas, Tais Zulemyan, Gokhan Ergene, Sahin Senay,
Sule Turgut Balci, Pinar Yalinay Dikmen, Yasemin Yavuz, Ahmet Alanay
Kushal Ramesh Gohil, Saumyajit Basu

Jason Pui Yin Cheung, Yifei Li, Kenneth Kwan Yee Wong, Teng Zhang“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-13-3

Evaluation of the Basal Metabolism of Degenerative Lumbar Intervertebral Discs Based on Pfirmann Grade and Presence of Instability
158
Chaiyapruk Pundee, Naomi N. Lee, Jacob S. Kramer, Aaron M. Stoker, Christina L. Goldstein, Don K. Moore,
Theodore J. Choma, James L. Cook

PS-FP-13-4

Basal and Cytokine-Stimulated Biomarker Production by Degenerative Lumbar Discs from Microdiscectomy versusInterbody Fusion Patients
159
Chaiyapruk Pundee, Theodore J. Choma, Jacob S. Kramer, Aaron M. Stoker, Christina L. Goldstein, Don K. Moore,
Naomi N. Lee, James L. Cook

PS-FP-13-5

Ubiquitin Mediated Proteasome Degradation Leading to Glutamic Acid Accumulation Could Be the Cause for Poor
Clinical Outcomes in Patients with Modic Changes
160
Dilip Chand Raja Soundararajan, Sharon Miracle Nayagam, Chitraa Tangavel, Sri Vijayanand K. S., Raveendran Muthurajan,
Ajoy Prasad Shetty, Rishi Mugesh Kanna, Rajasekaran Shanmuganathan

PS-FP-13-6

Histopathological and Cytogenetic Analysis of Lumbar Epidural Lipomatosis

160

PS-FP-13-7

Prolonged Use of Narcotics after Spine Surgery: A Requirement or a Privilege

161

PS-FP-13-8

Posterior Rod Strain in a Long Spinal Fusion to the Pelvis: An In-Vitro Experimental Study Using Synthetic Lumbopelvic Bone Models
162

Taketoshi Yasuda, Kayo Suzuki, Shoji Seki, Kenta Watanabe, Hiroto Makino, Takeshi Hori, Masahiko Kanamori,
Yoshiharu Kawaguchi
Muhammad Tahir Karim, Shehar Yar Abid, Shahid Ali

Shunji Tsutsui, Ei Yamamoto, Takuhei Kozaki, Akimasa Murata, Hiroshi Yamada

PS-FP-13-9

The Possible Involvement of the Oxidized LDL/LOX-1 System in Ligamentum Flavum Hypertrophy in the Patientswith Lumbar Spinal Canal Stenosis
162
Sota Nagai, Hiroki Takeda, Daiki Ikeda, Soya Kawabata, Kota Watanabe, Shinjiro Kaneko, Nobuyuki Fujita

PS-FP-13-12 Laser Resonance Frequency Analysis of Pedicle Screw Stability: A Cadaveric Model Bone Study

163

PS-FP-13-14 Do Academic Pediatric Orthopaedists Who Treat Spine Receive Increased Industry Funding?

164

Daisuke Nakashima, Katsuhiro Mikami, Shunsuke Kikuchi, Toshiyuki Kitamura, Noboru Hasegawa, Masaharu Nishikino,
Morio Matsumoto, Masaya Nakamura, Takeo Nagura
Alice Chu, Sean Haimowitz, Michael Fields, Lynn Ann Forrester, Leah Gonzalez, Lauren Seo, Caixia Zhao, Neil Kaushal,
Folorunsho Edobor-Osula

PS-FP-13-15 The Efficacy of C5a Receptor Antagonist for Human iPSC-Derived Neural Stem/Progenitor Cell Transplantation in the
Injured Spinal Cord of Mice164
Reo Shibata, Narihito Nagoshi, Keita Kajikawa, Yasuhiro Kamata, Shuhei Ito, Mahamad Khazaei, Michael G. Fehlings,
Morio Matsumoto, Hideyuki Okano, Masaya Nakamura

PS-FP-13-16 Cytokine Changes Cultured Cells Harvested from Cervical Spine of Patients with Ossification of the Posterior Longitudinal Ligament
165
Hideki Saito, Takafumi Yayama, Kanji Mori, Kosuke Kumagai, Masahiro KItagawa, Shinji Imai

PS-FP-13-17 Automatic Recognition of Whole Spine Sagittal Alignment and Curvature Analysis through a Deep Learning Technique
166
Yu-Jui Huang, Yu-Cheng Yeh, Chi-Hung Weng, Chen-Ju Fu, Chao-Yuan Yeh, Tsung-Ting TsaiPS-FP-13-19 Prognosis of Iatrogenic Spinal Cord Injury at a Major Rehabilitation Center in United Kingdom

166

Aashish Babanrao Ghodke, Navin Kumar

PS-FP-13-23 Accelerated Recovery Protocol Following Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis Leading to Early
Hospital Discharge
167
Teddy Suratos Fabila, Angela Siok Hoong Yeo, Mini Abraham, Narayani D/O Jayakrishnan, Shin Huey Ng,
Kevin Boon Leong Lim“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asianwww.asianspinejournal.org
pISSN 1976-1902 · eISSN 1976-7846

Spine Journal
Volume 15 ^ Number Supplement 1 ^ June 2021
PS-FP-13-24 How Much Experience Is Required to Acquire the Skills for Spinal Surgery? Results of a Survey of Spine Surgeons 168
Ryunosuke Fukushi, Mitsunori Yoshimoto, Naohisa Miyakoshi, Daisuke Kudo, Yoichi Shimada, Toshihiko Yamashita

PS-FP-13-25 Novel In Vivo Imaging System of Grafted Human Induced Pluripotent Cells-Derived Neuron Activity after Spinal Cord
Injury169
Kentaro Ago, Narihito Nagoshi, Morio Matsumoto, Hideyuki Okano, Masaya Nakamura

PS-FP-13-27 Comparison of the Global Sagittal Alignment and Surgical Outcomes for Osteoporotic Vertebral Body Fracture Between Lower Lumbar and Thoracolumbar Area
169
Tomoya Matsuo, Koki Uno, Kohei Kawakita, Teppei Suzuki, Masaaki Ito

PS-FP-13-28 Comparison of the Stability and Osseointegration of Different Intravertebral Fixators

170

PS-FP-13-29 Do Ovariectomy and Calcium-Restricted Diets Create Osteoporosis in Porcine Model?

170

PS-FP-13-30 Consideration of Cryopreservation Solutions and Methods of Nucleus Pulposus Cells for Industrialization

171

Jui-Yang Hsieh, Yi-You Huang, Jyh-Horng Wang, Po-Quang Chen

Jui-Yang Hsieh, Yi-You Huang, Yao-Horng Wang, Jyh-Horng Wang, Po-Quang Chen

Kosuke Sako, Daiske Sakai, Yoshihiko Nakamura, Erika Matsushita, Takayuki Warita, Natsumi Horikita, Masato Sato,
Masahiko Watanabe

PS-FP-13-31 Clinical Efficacy of Ultrasound Guided Bilateral Erector Spinae Block for Single Level Lumbar Fusion Surgery: A Prospective, Randomized, Case-Control Study
172
Chandhan Murugan, Vipin Goel, Madhan Mohan, Ajoy Shetty, Rajasekaran Shanmuganathan

PS-FP-13-32 The Effect of Anti-Receptor Activator of Nuclear Factor-κB Ligand Monoclonal Antibody on Spinal Fusion in a Mouse
Spinal Fusion Model
173
Soji Tani, Koji Ishikawa, Yoshifumi Kudo, Akira Matsuoka, Hiroshi Maruyama, Ryo Yamamura, Chiakara Hayakawa,
Koki Tsuchiya, Takashi Nagai, Nobuhiro Sakai, Mayumi Tsuji, Yuji Kiuchi, Tomoaki Toyone, Katsunori Inagaki

PS-FP-13-34 Efficacy of Human Induced Pluripotent Stem Cell-Derived-Gliogenic NS/PCs for Transplantation in the Chronic Phaseof Spinal Cord Injury
173
Yasuhiro Kamata, Mitsuhiro Inoue, Miho Isoda, Munehisa Shinozaki, Morio Matsumoto, Hideyuki Okano,
Masaya Nakamura, Jun Kohyama, Narihito Nagoshi

PS-FP-13-36 A Retrospective Audit of Effectiveness and Reliability of Telemedicine Consultations in Patients with Spinal Ailments		
174
Rohit Akshay Kavishwar, Ajoy Prasad Shetty, S. Rajasekaran

PS-FP-14-1

Intradiscal and Epidural Platelet-Rich Plasma Injection for the Treatment of Chronic Discogenic Low Back Pain

175

PS-FP-14-2

One-Year Clinical Result of Condoliase for Lumbar Disc Hernia

175

PS-FP-14-3

The Effectiveness of Chemonucleolysis with Condoliase for Treatment of Painful Lumbar Disc Herniation

176

PS-FP-14-4

Transforaminal Full Endoscopic Discectomy and Thermal Annuloplasty for High Signal Intensity Zone Radiculopathy		
176

En Song, Ji Zheng Li, Yan Lin Li, You Qing Huang, En Bin Wang, Fan Bing Li, Xiao Feng Yuan, Xue Song Chen, Yao Yu Xiang,
Xian Guang Yang
Atsushi Yoshioka, Kenichiro Tanaka, Yudo Hachiya

Eijiro Okada, Satoshi Suzuki, Satoshi Nori, Osahiko Tsuji, Narihito Nagoshi, Mitsuru Yagi, Nobuyuki Fujita,
Masaya Nakamura, Morio Matsumoto, Kota Watanabe

Kazuta Yamashita, Fumitake Tezuka, Masatoshi Morimoto, Kazuya Kishima, Kiyoshi Yagi, Koichi Sairyo“This journal was supported by the Korean Federation of Science and Technology Societies (KOFST) Grant funded by the Korean Government.”

Asian Spine Journal
ABSTRACTS

Asian Spine
Spine J 2021;Journal
15(Supplement 1):S1–S177 • http://dx.doi.org/10.4184/asj.2021.15.S1.S1
S1
Asian

APSS-APPOS 2021

(13th Combined Meeting of Asia Pacific Spine Society & Asia Pacific Paediatric Orthopaedic Society)

PS-BP-1

Significance of Vertebral Body Sliding
Osteotomy as a Surgical Strategy for theTreatment of Cervical Ossification of the
Posterior Longitudinal Ligament
Sehan Park1, Dong-Ho Lee2, Jae Hwan Cho2,
Chang-Ju Hwang2, Choon-Sung Lee2
1

Dongguk University Ilsan Hospital, Goyang, Korea
Asan Medical Center, Seoul, Korea

2

Study Design: Retrospective study.
Overview of Literature: Vertebral body sliding osteotomy(VBSO) was previously reported as a technique to decompress ossification of posterior longitudinal ligament(OPLL) by translating the vertebral body anteriorly. However, little is known about its clinical efficacy compared tolaminoplasty (LMP) and its significant in surgical strategy
for treatment of cervical myelopathy caused by OPLL.
Purpose: Therefore, this study aimed to evaluate the radiological and clinical efficacies of VBSO versus LMP for
treating myelopathy caused by OPLL.
Methods: Medical records and radiographic data of 97 patients with symptomatic OPLL-induced cervical myelopathy treated with VBSO or LMP (between 2012 and 2017)with follow-up for more than 2 years were retrospectively
reviewed. Results from 40 patients who underwent VBSO
(VBSO group) for the treatment of OPLL-induced myelopathy were compared with 57 patients who underwent
LMP (LMP group). Graft migration or dislodgement
was not observed in the VBSO group. One patient in the
VBSO group suffered a dural tear (2.5%, 1/40), and three
pseudarthrosis was detected (7.5%, 3/40).
Results: Cervical lordosis significantly increased in the
VBSO group postoperatively (p<0.01) but decreased in the
LMP group (p<0.01). Cervical lordosis was significantly

ASJ

higher in the VBSO group at 12 months postoperatively(p<0.01) and at the final follow-up (p<0.01). The minimum interval of the spinal cord increased significantly
only in the VBSO group and was significantly greater thanthat of the LMP group postoperatively (p<0.01). All patients in the VBSO group assessed as mK-line (-) preoperatively were assessed as mK-line (+) postoperatively. Final
Japanese Orthopaedic Association (JOA) score (15.1±1.8
vs. 13.8±1.9, p=0.02) and JOA score improvement (1.7±1.8
vs. 0.9±1.3, p=0.01) were significantly higher in the VBSO
group. Furthermore, JOA recovery ratio (45.1±38.4 vs.
27.4±35.7, p=0.03) and proportion of patients with a recovery rate ≥50% was significantly higher in the VBSO
group (p<0.01). An mK-line status change from (-) to(+) was significantly associated with a JOA recovery rate
≥50% (p<0.01).
Conclusions: The impacts of VBSO versus LMP included
the following: (1) effectively restoring lordosis; (2) inducing mK-line positivity; and (3) facilitating better neurologic recovery. VBSO also demonstrated a low rate ofcomplications. Therefore, VBSO can be included as a surgical strategy for treating OPLL-induced myelopathy thatis safe and effective both for sagittal alignment restorationand neurologic recovery.

PS-BP-2Comparison of the Clinical and Radiographic
Results between Cervical Artificial Disc
Replacement and Anterior Cervical Fusion:
10-Year Follow- up Study
Kai Yan, Chi Ma, Xiao Han, Da He, Wei Tian
Department of Spine Surgery, Beijing Jishuitan Hospital, Beijing, China

Purpose: To compare the long-term clinical and radio-

Copyright Ⓒ 2021 by Korean Society of Spine Surgery

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non–Commercial License (http://creativecommons.org/licenses/by–nc/3.0/)
which permits unrestricted non–commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Asian Spine Journal • pISSN 1976–1902 eISSN 1976–7846 • www.asianspinejournal.org

S2

Asian Spine J 2021;15(Supplement 1):S1-S177

graphic results of cervical artificial disc replacement(CADR) and anterior cervical discectomy and fusion(ACDF), and to provide our evidence whether CADR
could reduce adjacent segment degeneration.
Methods: One hundred and ninety patients with degenerative cervical spondylosis who underwent surgical treatment (Bryan CADR group 110 patients, ACDF group 80
patients) were enrolled during December 2003 to December 2007. The Japanese Orthopaedic Association scores,
Neck Disability Index (NDI), and the Odom’s score wereused to evaluate the clinical efficacy. Cervical radiographs,
computed tomography, and magnetic resonance imaging
were used to evaluate sagittal curvature, range of motion(ROM), and adjacent segment degeneration.
Results: For final follow-up, the follow-up rate of the
CADR group was 80.9%, average age was 46.5 years, average follow-up time was 127 months, 74 (83.1%) were1-level cases, and 15(16.9%) were bi-level cases. A totalof 73.8% of ACDF patients completed the final followup with an average age of 52.1 years. The average followup time was 124 months. There were 39 patients (66.1%)
with 1-level cases and 20 patients (33.9%) with bi-levelcases. Compared with preoperative, both groups were satisfied with the clinical efficacy. One-level cases of CADR
group NDI scores were significantly better than ACDF
group, and reoperation rate was significantly lower than
ACDF group. No statistical differences were found inother clinical scores. Both groups have maintained a goodsagittal cervical curvature. The mean ROM of index levelof CADR group is 8.5°, and ACDF index levels were 100%
fused. The ROM of adjacent segments and C2–7 in CADR
group was significantly better than that of the ACDF
group. Cervical degeneration score (CDS) of the adjacentsegments and Miyazaki grade of the intervertebral discwere degenerated postoperatively. The adjacent segmentdegeneration incidence of one-level cases in CADR group(upper level 31.1%, lower level 28.4%) was significantly
lower than ACDF group (upper level 56.4%, lower level
76.9%). The lower-level adjacent segment incidence of
CDS and Miyazaki grade in bi-level cases of ACDF groupwere significantly higher than those in CADR group.
Conclusions: At 10-year follow-up, both Bryan CADR and
ACDF patients were obtained excellent clinical outcomes.
Compared with ACDF, CADR had maintained a better cervical curvature and ROM, slowing the progress ofadjacent segment degeneration, in which one-level cases
better than bi-level patients.

PS-BP-3

Deep Learning Pipeline for AutomatedDetection and Classification of Central Canal,
Lateral Recess and Neural Foraminal Stenosis
on Lumbar Spine Magnetic Resonance Imaging
Jiong Hao Tan1, James Thomas Patrick Decourcy Hallinan2,
Lei Zhu3, Kaiyuan Yang4, Andrew Makmur2,
Diyaa Abdul Rauf Algazwi5, Yee Liang Thian2,
Samuel Lau2, Yun Song Choo2, Eide Sterling2,
Qai Ven Yap6, Yiong Huak Chan6, Naresh Kumar1,
Beng Chin Ooi4, Hiroshi Yoshioka7, Swee Tian Quek2
1

Department of Orthopedic Surgery, National University Hospital, Singapore
Department of Diagnostic Imaging, National University Hospital, Singapore
3
NUS Graduate School for Integrative Sciences and Engineering, National
University of Singapore, Singapore
4
Department of Computer Science, School of Computing, National
University of Singapore, Singapore
5Radiology Department, Dammam Medical Complex, Dammam, Saudi
Arabia6
Biostatistics Unit, Yong Loo Lin School of Medicine, Singapore
7
Department of Radiological Sciences, University of California Irvine, Irvine,
CA, USA2

Study Design: Retrospective study.
Overview of Literature: Assessment of lumbar spinal stenosis on magnetic resonance imaging (MRI) is repetitive
and time-consuming. Deep learning could improve theproductivity and consistency of reporting.
Purpose: To develop a deep learning pipeline (DLP) for
automated detection and classification of lumbar central
canal, lateral recess, and neural foraminal stenosis.
Methods: Retrospective extraction of MRI lumbar spines
was done from September 1, 2015 to September 1, 2018.
Five hundred studies were randomly selected with instrumentation or severe scoliosis excluded. Four hundredand forty-six studies were analyzed, encompassing 12,403
axial T2-weighted and 6,161 sagittal T1-weighted images.
The training/testing split was 89/11%. Training data werelabelled by four board-certified radiologists using pre-defined gradings (normal/mild/moderate/severe). A two-step
DLP was developed. First, a convolutional neural network(CNN) was trained to detect the region of interest (ROI),
followed by a second CNN for ROI classification. A heldout test set of 50 spines were labelled by a musculoskeletal
radiologist with 31-year experience (reference standard),
and subspecialist neuro (rad1) and musculoskeletal (rad2)
radiologists with 5- and 9-year experience, respectively.

Asian Spine Journal
DLP performance on an external dataset of 100 spines was
also evaluated. Detection recall (%), inter-rater agreement(Gwet’s kappa), and sensitivity/specificity/positive predictive value/negative predictive value (NPV) were calculated.
Results: DLP ROI detection recall ranged from 99.7%–
99.9%, 95.2%–99.3%, and 84.5%–96.2% for central canal,
lateral recesses, and neural foramina, respectively, whichwere comparable with subspecialist radiologists (range,
83.9%–99.9%). On the internal dataset, dichotomous
DLP classification (normal/mild versus moderate/severe)
showed almost-perfect agreement for rad1, rad2 and theaverage DLP with kappa of 0.98/0.98/0.96 for central canal, 0.92/0.95/0.92 for lateral recesses, and 0.94/0.95/0.89
for neural foramina, respectively (p<0.001). For external
testing, almost-perfect agreement for the average DLP
was seen for dichotomous classification of all ROIs (range,
0.95–0.96). The DLP demonstrated high specificity(91.9%–97.9%) and NPV (96.3%–99.7%) for dichotomousclassification of all ROIs.
Conclusions: The DLP showed comparable agreement tosubspecialist radiologists for detection and classificationof central canal and lateral recess stenosis, with slightly reduced agreement for neural foraminal stenosis on lumbar
spine MRI.

PS-BP-5

Prediction of Final Outcome after Posterior
Correction with Lower Instrumented Vertebra
L3 or L4 for the Correction of StructuralThoracolumbar/Lumbar Curve-Minimum
5-Year Follow-up
Kun-Bo Park1, Choon Sung Lee2, Sehan Park3
1

Division of Pediatric Orthopedic Surgery, Severance Children’s Hospital,
Yonsei University College of Medicine, Seoul, Korea
2
Department of Orthopedic Surgery, Asan Medical Center, University of
Ulsan College of Medicine, Seoul, Korea
3
Department of Orthopedic Surgery, Dongguk University Ilsan Hospital,
Goyang, Korea

Purpose: It is questionable to predict postoperative curve
magnitude and balance in standing position while performing intraoperative correction during scoliosis surgery,especially coronal alignment below lower instrumented
vertebra (LIV). The purpose of this study was to evaluate
the efficacy of intraoperative radiography for the predic-

S3tion of standing radiography in patients with structuralthoracolumbar/lumbar curve (TL/L).
Methods: Patients with idiopathic scoliosis who had undergone the posterior correction and fusion for the structural TL/L curve and followed more than 5 years were recruited. Eighty-three patients were included and the mean
age was 16 years 6 months. LIV was L3 in 46 patients andL4 in 35 patients. Preoperative, intraoperative, postoperative, and final follow-up radiographs were used for theevaluation.
Results: At final follow-up, TL/L curve Cobb’s angle, discwedge angle below LIV, and vertebral body tilt below
LIV were significantly improved in both groups. In LIV
L3 group, however, disc wedge angle below LIV was not
improved postoperatively and disc wedge angle at final
follow-up was increased compared with postoperative value. In the intraoperative prone radiography, TL/L curve
Cobb’s angle and vertebral body tilt below LIV were significantly correlated to the postoperative and final followup evaluation in both groups, but disc wedge angle below
LIV showed a significant correlation only to the value atfinal follow-up in LIV L3 group (r=0.322, p=0.018).
Conclusions: TL/L Cobb angle and vertebral body tilt
below LIV in the intraoperative prone radiography was
highly correlated to the standing radiography at postoperation and final follow-up. Disc wedge angle below LIV
was not correlated to the postoperative standing radiography. However, the increased final disc wedge angle below
LIV may be predicted by prone radiography if the LIV
was L3.

PS-BP-6

Better Patient Experience Improves Outcomesin Pediatric Patients with Scoliosis
Yi Ling Chua
Department of Orthopaedics, KK Women and Children’s Hospital, Singapore

Purpose: To investigate if there is a relationship between
the experience of patients with adolescent idiopathic scoliosis (AIS) and their outcomes from self-reported questionnaires.
Methods: This study was carried out in a tertiary children’s
hospital with a one-stop facility for pediatric scoliosis. Between April and August 2020, patients with AIS were ad-

S4Asian Spine J 2021;15(Supplement 1):S1-S177

ministered the refined Scoliosis Research Society 22-item(SRS22r) and EuroQol five-dimensional (EQ-5D) questionnaires (patient-reported outcome measures, PROMs)
and the National Research Corporation (NRC) outpatientquestionnaire for pediatric patients (patient-reported
experience measures, PREMs). The SRS22r questionnaireevaluated function, pain, self-image, mental health, andmanagement satisfaction. The EQ-5D contained five questions on function, pain, and mood. The NRC outpatientquestionnaire evaluated patient experience and interaction with healthcare staff during outpatient follow-up.
Postoperative patients and those awaiting surgery were
excluded. Bivariate Pearson correlation was utilized fortesting relationships between PREMs and PROMs.
Results: Three hundred completed surveys were analyzed. One hundred and fifty-five patients (51.7%) withan average Cobb angle of 21° were managed by observation, while the remaining 145 (48.3%) with an average
Cobb angle of 33° were managed by bracing (per SRS
criteria). There were more females in the observation
and bracing groups (p=0.0012) but no statistical difference in age. Compared with the observation group, thebrace group had significantly poorer function (4.5±0.52
vs. 4.3±0.58), self-image (3.6±0.57 vs. 3.4±0.57), and total SRS-22r scores (4.1±0.38 vs. 4.0±0.42) (p=0.001 forall). Both groups had similar pain (4.6±0.46 vs. 4.6±0.47,
p=0.104), mental health (3.9±0.68 vs. 3.8±0.72, p=0.118),
and distribution of EQ-5D values. In the brace group, selfimage correlated significantly with how well the care teamworked with the patient, whether they interacted with thepatient in an age-appropriate manner, if the patient wasgiven a say in her care, and whether her privacy was respected during the clinic visit (r=0.35, p<0.001). There iscorrelation between the patient’s perception that privacy
was ensured by various healthcare staff during the visit
and their overall SRS-22r scores (r=0.32, p<0.001). There
was no relationship between PREMs and PROMs in theobservation group.
Conclusions: In pediatric patients with AIS on brace treatment, their self-image is influenced by a care team who
communicates in an age-appropriate manner, involves her
in the management plan, and respects her privacy. In theobservation group, there was no demonstrable relationship between PREMs and PROMs. Greater attention andfocus to particular aspects of the clinical encounter as
outlined above may improve patient-reported outcomesin AIS.

PS-BP-7

Clarifying the Therapeutic Effect of Grafted
Human-Induced Pluripotent Stem CellDerived Neurons in Spinal Cord Injury by
Chemically Controlling Neuronal Activity
Takahiro Kitagawa1, Narihito Nagoshi1, Yasuhiro Kamata1,
Morio Matsumoto1, Hideyuki Okano2, Masaya Nakamura1
1

Department of Orthopedic Surgery, Keio University, Tokyo, Japan
Department of Physiology, Keio University, Tokyo, Japan

2

Purpose: The therapeutic effect of human-induced pluripotent stem cell-derived neural stem/progenitor cells(hiPSC-NS/PCs) transplantation to the subacute phaseof spinal cord injury (SCI) animals has been previously
reported, yet the mechanism of recovery has not been
elucidated. Clarifying the therapeutic effect of engrafted
cells indicates the necessity of NS/PCs transplantation andcould directly link to a further improvement of this therapy. The purpose of the present study was to evaluate thecontribution of grafted neuronal function to the recovery
of host locomotor activity.
Methods: To determine the functional effect of graftedneuron activity, transplanting NS/PCs were geneticallymodified by lentiviral vectors. First, NS/PCs coding TREGFP-2A-WGA/EF1-rtTA (WGA-NS/PCs), which expressa trans-synaptic tracer wheat germ agglutinin (WGA) incontrol of doxycycline administration, was transplanted
to Th10 contusion injury model of mice. Ten weeks after
transplantation, the spreading of WGA in the spinal cord
section was immunohistologically assessed to evaluate thesynaptic formation of the grafted neurons. Second, NS/
PCs coding hSyn-hM4Di-mCherry (hM4Di-NS/PCs),
which express a chemogenetically-engineered receptor
that permits temporal inhibition by synthetic ligand clozapine N-oxide (CNO), and NS/PCs coding hSyn-mCherry (mCherry-NS/PCs), as a control, were transplanted
to SCI mice. CNO administration assay, evaluating thechange of Basso Mouse Scale (BMS) score and treadmill
gait analysis before and after CNO administration, wasperformed 10 weeks after transplantation.
Results: Immunohistological analysis of WGA-NS/PCs
transplanted mice revealed a trans-synaptic migration of
WGA to host neurons. WGA migrated not only to theneurons nearby the graft cells but also to the motor neurons in the caudal site; suggesting the integration of graftAsian Spine Journal
neurons to the host motor circuits. By CNO administration assay of hM4Di-NS/PCs and mCherry-NS/PCs transplanted mice, BMS score (pre-CNO=3.3, post-CNO=3.1;
p=0.021) and parameters of treadmill gait analysis (stride
length: pre-CNO=4.0 cm, post-CNO=3.5 cm; p=0.003;
paw angle: pre-CNO=22.7°, post-CNO=31.0°; p=0.027)
has significantly deteriorated in hM4Di-NS/PCs transplanted mice. These results suggest that inhibiting theneuronal function of grafted neurons guide to a relapse offunctional disorder by SCI.
Conclusions: Grafted neurons derived from hiPSC-NS/
PCs transplanted to SCI animals integrate to host neuralcircuit and contribute to the functional recovery of hostanimals.

PS-BP-8

Long-Term Selective Stimulation of Transplanted
Neural Stem/Progenitor Cells for Spinal
Cord Injury Improves Locomotor Function
Mediated by Increased Synaptic Transmission
Momotaro Kawai1,2, Narihito Nagoshi1, Kent Imaizumi2,
Mitsuru Ishikawa2, Munehisa Shinozaki2,
Shinsuke Shibata2,4, Yusuke Saijo1,2, Yu Suematsu1,2,
Takayuki Nishijima1,2, Takashi Yoshida2,3,
Takahiro Shibata1,2, Shogo Hashimoto1,2,Takahiro Kitagawa1,2, Kentaro Ago1,2, Keita Kajikawa1,2,
Reo Shibata1,2, Yasuhiro Kamata1,2, Morio Matsumoto1,
Hideyuki Okano2, Masaya Nakamura1
1

Department of Orthopaedic Surgery, Keio University School of Medicine,Tokyo, Japan2
Department of Physiology, Keio University School of Medicine, Tokyo, Japan3
Department of Rehabilitation Medicine, Keio University School of Medicine,Tokyo, Japan
4
Division of Microscopic Anatomy, Graduate School of Medical and Dental
Sciences, Niigata University, Niigata, Japan

Purpose: It has been reported that transplantation ofhuman-induced pluripotent stem cell-derived neural
stem/progenitor cells (hiPSC-NS/PCs) is effective forfunctional recovery after spinal cord injury (SCI) and thatthe efficacy of hiPSC-NS/PCs transplantation is highly dependent on the host spinal cord environment. Meanwhile,the damaged spinal cord tissue is known to be modified
by interventions for neural circuits, such as rehabilitations and electrical stimulations. We hypothesized that
selective stimulation of transplanted hiPSC-NS/PCs after

S5

SCI can enhance motor function recovery by intensifying interaction between the transplanted hiPSC-NS/PCs
and the damaged tissue, and improving the host environment. Therefore, the present study aims to investigate theeffect of long-term repetitive and selective stimulation oftransplanted hiPSC-NS/PCs on the surrounding damaged
spinal cord tissue.
Methods: For selective stimulation of transplanted cells,
we used hM3Dq, which is one of the Designer Receptors
Exclusively Activated by Designer Drugs. First, hM3Dq
was lentivirally transfected to hiPSC-NS/PCs. These hM3Dq-hiPSC-NS/PC-induced neural cells (hM3Dq-neuralcells) were treated with clozapine N-oxide (CNO), and theintracellular response was investigated by RNA sequenceand Fluo-8 intracellular calcium indicator. Second, theextracellular response from CNO administered hM3Dqneural-cells to neighboring neurons was recorded utilizing GCaMP calcium indicator. Next, contusive SCI was
induced in NOD-SCID mice, and the hM3Dq-hiPSC-NS/
PCs were transplanted into the lesion epicenter 9-day after
SCI. After transplantation, CNO was intraperitoneally injected every day for the transplantation-CNO group andphosphate-buffered saline was intraperitoneally injected
for the control group. mRNA sequence, protein quantification by capillary electrophoresis, and histological analyses were performed on days 14 and 42 after SCI. Motorfunction was assessed by the Basso Mouse Scale (BMS)
score, Rota-rod test, DigiGait analysis, and kinematics.
Results: RNA sequence revealed that CNO-administeredhM3Dq-neural-cells expressed activity-related genes. Besides, CNO-administered hM3Dq-neural-cells enhanced
their intracellular calcium concentration and activatedneighboring GCaMP-positive neurons in vitro. Expressions of synapse-related genes and proteins were enhanced
on day 14 after SCI in the transplantation-CNO group. On
day 42, axial spinal cord areas of the transplantation-CNO
group were larger. Graft-to-host synapse formation was
detected in immunoelectron microscopic examination.
Consequently, motor functions significantly improved in
the transplantation-CNO group, which was assessed by the
BMS score, Rotarod test, DigiGait analysis, and kinematics.
Conclusions: Long-term repetitive and selective stimulationof transplanted hiPSC-NS/PCs enhanced synaptic transmission, increased synapse-related gene and protein expressions, preserved host spinal cord tissue, and improved motor
functions. Selective stimulation after cell transplantation canbe an effective adjuvant therapy for SCI.

S6Asian Spine J 2021;15(Supplement 1):S1-S177

PS-BP-9Novel Biomarkers of Health and Degenerationin Human Intervertebral Discs: In-Depth
Proteomic Analysis of Collagen Frameworkof Fetal, Healthy, Scoliotic, Degenerate andHerniated Discs
Dilip Chand Raja Soundararajan1, Sharon Miracle Nayagam2,
Sri Vijayanand Ks1,2, Raveendran Muthurajan3,
Sunmathi R2, Chitraa Tangavel2, Ajoy Prasad Shetty1,
Rishi Mugesh Kanna1, Rajasekaran Shanmuganathan1
1

Department of Spine Surgery, Ganga Hospital, Coimbatore, India
Department of proteomics, Ganga Research Centre, Coimbatore, India
3
Tamilnadu Agricultural University, Coimbatore, India
2

Purpose: Alterations in the collagen (COL) composition
have been co-related to degenerative disc disease. Though
28 different types of COLs are present in humans, mostof the literature is focused only on COL-1 and COL-2.
The current study aimed to analyze the entire COL composition of human intervertebral disc (IVD) across fetal(developmental phenotype), normal (healthy phenotype),scoliotic (early degeneration), herniated (degenerate phenotype), and degenerated (degenerate phenotype) IVDs
using high-end proteomic technology.
Methods: Nucleus pulposus (NP) tissues were segregatedfrom IVDs harvested from five different disc phenotypes.
The fetal spine procured from specimens following medical termination of pregnancy underwent microscopic
dissection for harvesting NP under sterile conditions.
Excised NP tissues were washed with phosphate buffer
solution and snap-frozen in liquid nitrogen (LN2, -196°C)
immediately before subjecting to proteomic analysis.
Results: Tandem mass spectrometric analysis revealed a
total of 1,050 proteins in fetal discs (FD); 1,809 in ND;
1,487 in segment degeneration (SD); 1,859 in disc herniation (DH); and 1,538 in disc degeneration (DD) group.
Since the COLs are the principal constituent of the extracellular matrix, they were screened selectively. Out of 28
major types of COLs reported in the human body, thisstudy identified 24 different types of COL with 34 subtypes in NP of the study samples. FD expressed 14 different major types of COL, compared to 10 (ND), 11 (SD),15 (DH), and 19 in DD groups. COLs types 1, 2, 6, 11, and14 were found in all the groups along with their sub-types.
COL type 22 was found only in FD group whereas type15, 25, 26, and 27 were found only in DD group. Amongst

the fibril forming COLs, the abundance of COL-1 and 11
were highest amongst FD representing their role in development of NP. In addition, COL-24 was highly abundantin normal discs indicating their role in homeostasis. Of
notable importance was the higher expression of COL-7(anchoring-fibril forming), COL-10 (network forming),
and Col-15 (Multiplexin) in normal discs.
Conclusions: The selective proteomic analysis of COL
composition in this study has revealed novel moleculartargets for further exploration on its regenerative potential. Apart from COL-1 and COL-2, other important
COLs (6,7,10, and 15) required for homeostasis wereidentified. More importantly, COLs abundantly expressedin fetal phenotype (COL-1, 6, 9, 12, and 14) could be explored for regenerative potential.

PS-FP-1-2

Fusion and Subsidence Rates of Vertebral Body
Sliding Osteotomy: Comparison of Three
Reconstructive Techniques for Multilevel
Cervical Myelopathy
Sehan Park1, Dong-Ho Lee2, Jae Hwan Cho2,
Chang Ju Hwang2, Choon Sung Lee2
1

Dongguk University Ilsan Hospital, Goyang, Korea
Asan Medical Center, Seoul, Korea

2

Purpose: Vertebral body sliding osteotomy (VBSO) was previously reported as a technique to decompress spinal canalby translating the vertebral body anteriorly and is indicatedfor cervical myelopathy caused by spondylosis or ossification of the posterior longitudinal ligament. However, little is
known about its fusion and subsidence rates. The study was
conducted to compare the fusion and subsidence rates of
VBSO, anterior cervical discectomy and fusion (ACDF), andanterior cervical corpectomy and fusion (ACCF).
Methods: One hundred and sixty-eight patients who
underwent VBSO, ACDF, or ACCF for the treatment ofcervical myelopathy and were followed-up for more than
2 years were retrospectively reviewed. Fusion and subsidence rates, Visual Analog Scale (VAS) scores for neckpain, Neck Disability Index (NDI), and Japanese Orthopaedic Association (JOA) scores were assessed. Results of
the VBSO, ACDF, and ACCF groups were compared.
Results: The fusion rate at 1-year postoperatively and theAsian Spine Journal
final follow-up for VBSO was 92.9% (37/42). VBSO demonstrated a higher 1-year fusion rate than ACDF (77.9%[74/95], p=0.04) and ACCF (74.2% [23/31], p=0.04). The
mean amount of subsidence (ACDF group, 1.5±1.2 mm;
VBSO group, 1.5±1.5 mm; p=1.00) and rate of significant
subsidence of >3 mm (ACDF group, 13.7% [13/95]; VBSO
group, 14.3% [6/42]; p=1.00) were similar for ACDF and
VBSO. Furthermore, the mean amount of subsidence in
VBSO was significantly less than that in ACCF (1.5±1.5 mm
vs. 2.4±2.0 mm, p=0.04). Neck pain VAS, NDI, and JOA
scores were not significantly different among the groups.
Conclusions: VBSO demonstrated a higher solid fusion
rate at 1-year follow-up than ACDF and ACCF and lesssubsidence than ACCF. VBSO could be applied safely
when the shape/location of the pathologic foci and sagittalalignment favor its application without much concern forpseudarthrosis or subsidence.

PS-FP-1-5

What is the Risk of Cervical Deformity after
Posterior Cervical Decompression Surgery?: A
Multicenter Study
Shin Oe1,2, Kenta Kurosu3,4, Tomohiko Hasegawa3,5,
Satoshi Shimizu6, Go Yoshida3,7, Tomotada Fujita8,
Sho Kobayashi9, Tomohiro Yamada3,10, Koichiro Ide3,6,
Keiichi Nakai3,11,Kumiko Yotsuya3,8, Yu Yamato1,
Tatsuya Yasuda11, Tomohiro Banno3, Hideyuki Arima3,
Yuki Mihara3, Hiroki Ushirozako3, Yuh Watanabe3,
Yukihiro Matsuyama3
1

Division of Geriatric Musculoskeletal Health, Department of Orthopaedic
Surgery, Hamamatsu University School of Medicine, Hamamatsu, Japan2
Department of Orthopaedic Surgery, Haibara General Hospital, Haibara, Korea
3
Department of Orthopaedic Surgery, Hamamatsu University School of
Medicine, Hamamatsu, Japan
4
Department of Orthopaedic Surgery, Shizuoka City Hospital,Shizuoka, Japan
5
Department of Orthopaedic Surgery, Japanese Red Cross Hamamatsu
Hospital,Hamamatsu, Japan
6
Department of Orthopaedic Surgery, Narita Memorial Hospital, Toyohashi,Japan
7
Department of Orthopaedic Surgery, Aoyama Hospital, Toyokawa, Japan
8
Department of Orthopaedic Surgery, Enshu Hospital, Hamamatsu, Japan
9
Department of Orthopaedic Surgery, Hamamatsu Medical Center,
Hamamatsu, Japan10
Department of Orthopaedic Surgery, Kikugawa General Hospital, Kikugawa,Japan
11
Department of Orthopaedic Surgery, Iwata City Hospital, Iwata, Japan

Purpose: Posterior decompression surgery (such as lami-

S7

noplasty) for cervical spondylotic myelopathy (CSM) andossification of the posterior longitudinal ligament (OPLL)
has been a common surgery; however, it can cause iatrogenic kyphosis and cervical deformity (CD). The purposeof this study was to investigate the risk factors for CD after
posterior cervical decompression surgery.
Methods: The participants were 193 patients who underwent cervical posterior laminoplasty or laminectomy at
our hospital or satellite hospital for CSM or OPLL between 2010 and 2019. CD was defined as a C2–7 sagittal
vertical axis (SVA) ≥40 mm or a cervical lordosis angle(CL) ≤-10° on a standing radiograph. The participants
were divided into two groups: no cervical deformity(NCD; patients without CD before surgery) and CD (patients with CD before surgery). NCD group was divided
based on the presence of CD as follows: iatrogenic CD(ICD) and no ICD (NICD).
Results: There were 153 patients in the NCD group, 40
in the CD group, 126 patients in NICD, and 27 in the
ICD group. CD was still found in 34 patients (85%) in
the CD group 1 year after surgery. The revision rate wassignificantly higher in CD group (5%) compared to NCDgroup (p=0.042). There was significant difference in thenumber of decompressed lamina (NICD:ICD=4.1:4.5),
the presence of C2 decompression (2, 11%), and C5 palsy(0, 11%). The risk factors for CD, ICD, and CL ≤-10° 1
year after surgery as assessed by multiple logistic regression analysis were preoperative C2–7 SVA ≥30 mm (oddsratio [OR], 19.0; 95% confidence interval [CI], 8.5–42.4),
decompression of C2 or C7 lamina (OR, 3.1; 95% CI,
1.2–8.0), and preoperative CL ≤2° (OR, 42.0; 95% CI,
8.3–211.0), respectively.
Conclusions: To prevent postoperative CD, it is important
to avoid decompression of the C2 or C7 lamina as muchas possible. Moreover, in cases with CD, C2–7 SVA ≥30
mm or CL ≤2° before surgery, it is important to explain
the risks and consider to add fusion surgery.

S8

Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-1-6

The Effect of Using Lamina Spacer on
Postoperative Cervical Alignment and Rangeof Motion in Double-Door Laminoplasty
Akinobu Matsushita, Kenichi Kawaguchi, Hirokazu Saiwai,
Keiichiro Iida, Yasuharu Nakashima
Department of Orthopaedic Surgery, Graduate School of Medical Sciences,
Kyushu University, Fukuoka, Japan

Purpose: The purpose of this study is to examine the effects of the use of lamina spacers on postoperative cervical spine alignment and range of motion in double-doorlaminoplasty.
Methods: One hundred thirty-five consecutive patientswith cervical spondylotic myelopathy (91 males and 44 females; mean age, 69.7 years) who underwent double-doorlaminoplasty were enrolled. Sixty-seven patients wereused the lamina spacer (Kurokawa’s method) (S group),
and 68 patients were not used the lamina spacer (KiritaMiyazaki’s method) (N group). The follow-up period was
12 months. All patients were allowed to sit up and walkon the second postoperative day using an orthosis, which
was removed within the first 10 days. Cervical range of
motion (ROM) exercises were performed as a part of
the rehabilitation schedule. Radiography was performed
before surgery and 12 months after the operation. Cervical alignment in the neutral and flexion-extension view
were measured by the Cobb method at C2–C7. The ROM
was assessed by measuring the difference in alignment
between flexion and extension. In addition, Japanese Orthopaedic Association (JOA) score before and 12 months
after surgery and improvement rate of JOA score were
examined for clinical evaluation.
Results: There were no significant differences between thetwo groups in age, sex, and number of operated lamina
at the time of surgery. The mean C2–C7 alignment in theneutral position was 15.8° lordotic in the S group and
12.3° lordotic in the N group preoperatively, and was 11.1°
lordotic in the S group and 7.4° lordotic in the NS groupat 12 months after the operation. There was no significant
difference between preoperative and postoperative C2–
C7 alignment between the two groups. The mean ROM
decreased from a preoperative value of 38.9° to 28.3° at
12 months after the operation in the S group, and 38.3° to
33.4° in the N group. A significant decrease was observedin the S group. The JOA score improved from 9.21 before
surgery to 13.2 after surgery in the S group, and from 9.7
to 13.4 in the N group. There was no difference between
the two groups.
Conclusions: In double-door laminoplasty, the use oflamina spacers did not differ in postoperative cervicalsagittal alignment and clinical outcome. However, it wassuggested that the use of the lamina spacer reduces the
postoperative cervical ROM.

PS-FP-1-7K-line (−) in the Neck-Flexed Position Negatively
Affects Surgical Outcome of Expansive OpenDoor Laminoplasty for Cervical Spondylotic
Myelopathy
Satoshi Nori, Narihito Nagoshi, Satoshi Suzuki,
Osahiko Tsuji, Eijiro Okada, Mitsuru Yagi,
Masaya Nakamura, Morio Matsumoto, Kota Watanabe
Department of Orthopaedic Surgery, Keio University School of Medicine,Tokyo, Japan

Purpose: The K-line in the neck-flexed position (FKline) on radiography reflects dynamic factors and cervicalalignment. Although the FK-line has been reported to affect the neurological recovery after muscle-preserving selective laminectomy for cervical spondylotic myelopathy(CSM), its influence on surgical outcomes after expansive
open-door laminoplasty (ELAP) has not been investigated. The current study aimed to investigate the association between the FK-line and the radiological and surgicaloutcomes after ELAP. The influence of the FK-line on thesurgical outcomes after ELAP was analyzed with a multivariate analysis.
Methods: We reviewed the surgical outcomes in 81 patients with multilevel CSM who underwent C4–C6 ELAP
combined with C3 and C7 partial laminectomy using
a laminoplasty plate and were followed up for at least 2
years. We defined the FK-line (−) as some portion of abony spur or the vertebral body crossing the FK-line,
whereas the FK-line (+) was defined as that never crossing the FK-line. Patients were divided into the FK-line (+)(n=61) and FK-line (−) groups (n=20), and the surgicaloutcomes were compared between the group. A multivariate analysis was performed to identify the factors that

Asian Spine Journal
influenced the neurological outcomes.
Results: The FK-line (−) group had a smaller C2–C7
angle (preoperatively, p=0.001; postoperatively, p<0.001),
smaller C7 slope (preoperatively, p<0.001; postoperatively, p=0.001) greater postoperative increase in the C2–
C7 sagittal vertical axis (p=0.001), greater kyphosis in
cervical flexion (preoperatively, p<0.001; postoperatively,
p<0.001) and less lordosis in cervical extension (preoperatively, p=0.004; postoperatively, p=0.005), and higher incidence of postoperative residual spinal cord compression(p=0.017). The preoperative to postoperative changes in
the Japanese Orthopedic Association (JOA) score (1.1±0.7
vs. 2.5±1.7, p<0.001) and JOA score recovery rate (RR)
(24.9±14.3 vs. 52.3±27.5, p<0.001) were lower in the FKline (−) group. The multiple linear regression analysis revealed that the FK-line (−) (β=−0.327, p=0.011) and highsignal intensity (SI) changes on T2-weighted imaging (WI)
combined with the low SI changes on T1–WI in the spinal cord (β=−0.320, p=0.013) negatively affected the JOA
score RR.
Conclusions: The FK-line (−) negatively affected the surgical outcomes after ELAP in the patients with CSM. The
FK-line can be used for patients with CSM as a useful indicator of surgical outcomes after ELAP.

PS-FP-1-8

Preoperative Severity of Spinal Cord Compression
and Its Restoration during the Early
Postoperative Period Affect the Developmentof C5 Palsy
Masahiro Mizutani, Takashi Fujishiro, Takuya Obo,Atsushi Nakano, Yoshiharu Nakaya, Sachio Hayama,
Yoshitada Usami, Masashi Neo
Osaka Medical College, Takatsuki, Japan

Purpose: C5 palsy (C5P) is a known complication of cervical decompression surgery. The tethering effect of the
C5 nerve root following the posterior shift of the spinal
cord is the most accepted pathologic mechanism; however, this mechanism cannot fully explain C5P by itself inclinical practice. Separately, some studies have suggested
that preoperative severe spinal cord compression andpostoperative morphological changes in the spinal cord
affect C5P development; however, no previous study has

S9quantitatively addressed these possibilities. The aim of thisstudy was to examine whether spinal cord morphology
and morphological restoration after surgery affect C5P
development.
Methods: We reviewed consecutive patients with degenerative cervical myelopathy who underwent laminoplasty
including the C3/C4 and C4/C5 intervertebral disc levels.
All participants underwent magnetic resonance imaging
both preoperatively and within 4 weeks postoperatively.
To assess the severity of spinal cord compression, thecompression ratio (CR, spinal cord sagittal diameter/transverse diameter) was calculated. As an index of morphological changes in the spinal cord during the early
postoperative period, the change rate of CR (CrCR, %)was calculated as CR within 4 weeks postoperatively/
CRpreoperatively×100. These measurements were performed at both the C3/C4 and C4/C5 intervertebral disclevels. The study cohort was divided into C5P and nonC5P (NC5P) groups; then, CR and CrCR, in addition toother radiographic variables associated with C5P development, were compared between the groups.
Results: A total of 114 patients (mean age, 67.6 years;
58.8% men) were included in the study, with five and
109 patients in the C5P and NC5P groups, respectively.
Preoperative CR at both the C3/C4 and C4/C5 levels was
significantly smaller in the C5P group than in the NC5P
group (0.35 vs. 0.44, p=0.042; 0.27 vs. 0.39, p=0.021). Patients with C5P exhibited significantly greater CrCR at
the C3/C4 level than those without (139.3% vs. 119.0%,
p=0.046), but the same finding was not noted for CrCR at
the C4/C5 level. There were no significant differences inother variables between the groups.
Conclusions: This study reveals that severe compression of
the spinal cord and its greater morphological restoration
during the early postoperative period affect C5P development. These findings could support the involvementof segmental cord disorder theory, characterized as thereperfusion phenomenon, in the pathomechanism of C5P,
besides the tethering effect.

S10

Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-1-9

A Multicentre, Prospective, Randomized
Controlled Trial Comparing Efficacy and
Safety of ProDisc–C to Anterior Cervical
Discectomy and Fusion for Treatment ofSymptomatic Cervical Disc Disease
Naresh Kumar1, Leonard Vornov2, Chi Chien Niu3,
Hee-Kit Wong1
1National University Health System, Singapore
2Centinel Spine, West Chester, PA, USA
3
Chang Gung Memorial Hospital, Taipei, Taiwan

Purpose: The aim was to compare safety and efficacy of
ProDisc–C, a cervical total disc replacement (TDR) device to anterior cervical discectomy and fusion (ACDF)
in treating single-level symptomatic cervical disc disease(SCDD) in Asians. We hypothesized ProDisc–C to be
non-inferior to ACDF with lower incidence of adjacentsegment disease (ASD).
Methods: This multicenter, prospective, randomized controlled trial was initiated in January 2008, after obtaining
ethical approval at nine centers (in China/Hong Kong/Korea/Singapore/Taiwan). Patients with single-level SCDD
involving C3–C7-vertebral segments were enrolled andrandomized in 2:1 ratio into: group A treated with ProDisc–C and group B with ACDF. A protocol modification(January 2010) allowed patients with cervical myelopathy
also to be included. Assessments were conducted at baseline, 6 weeks, 3/6/12/18/24 months post-surgery and annually thereafter out to 84 months. The primary endpoint
was an overall success, the composite of (1) improvementin Neck Disability Index (NDI) by 20% from baseline; (2)maintained/improved neurologic parameters; (3) no implant removal/revision/re-operation/additional fixation atindex-level; and (4) no adverse events related to implant/
surgery and no severe/life-threatening events. Secondary
endpoints included: (1) incidence of ASD at 24 months; (2)individual endpoints of primary outcome; (3) outcomesof short-form survey (SF-36), Visual Analog Scale (VAS)
score (neck/arm-pain intensity/frequency; patient’ satisfaction); and (4) radiological parameters (range of motion, ROM).
Results: Of the 120 enrolled/treated patients (80 ProDisc–C, 40 ACDF), 76 with ProDisc–C and 37 with ACDF
were treated as per protocol (PP). Overall success (PP, last

observation carried forward [LOCF]) was 79% in group
A and 83.8% in group B at 24 months (p=0.10). ProDiscC demonstrated non-inferiority to ACDF at 18 months(81.6% vs. 83.8%, p=0.0398) with borderline non-inferiority at 3 months (76.3% vs. 78.4%, p=0.054). In intentto-treat-LOCF analysis, overall success at 24 months was
78.2% with ProDisc–C and 81.6% with ACDF (p=0.06).
ProDisc–C demonstrated non-inferiority to ACDF
at both 3 months (75.6% vs. 76.3%, p=0.0396) and 18
months (80.8% vs. 81.6%, p=0.0284). Secondary outcomes
improved after 24 months for both groups with no significant differences between groups for percentage change
from baseline. Occurrence of ASD was higher in ACDF
versus ProDisc–C, with no statistical significance. The
ROM was sustained with ProDisc–C at 24 months whencompared to preoperative ROM. Whilst, loss of ROM wasnoted in group B.
Conclusions: Cervical TDR with ProDisc–C is feasible,safe, and effective for treatment of SCDD in Asians. ProDisc–C was non-inferior to ACDF at 3 and 18 months
after index-surgery with no clear non-inferiority at 24
months. Patients treated with ProDisc–C demonstrated
significant improvement in terms of NDI, neurologic success, VAS-pain scores, and SF-36, along with preservationof ROM at 24 months post-surgery. Incidence of ASD wascomparable between the two groups at 24 months.

PS-FP-1-13

Gap between Flexion and Extension Range of
Motions: A Novel Indicator to Predict the Lossof Cervical Lordosis after Laminoplasty for
Cervical Spondylotic Myelopathy
Takashi Fujishiro1,2, Sachio Hayama1, Takuya Obo1,
Yoshiharu Nakaya1, Atsushi Nakano1, Yoshitada Usami1,
Ichiro Baba1, Masashi Neo1
1

Department of Orthopedic Surgery, Osaka Medical College, Takatsuki,
Japan
2
Department of Orthopedic Surgery, First Towakai Hospital, Takatsuki,
Japan

Purpose: Kyphotic deformity resulting from loss of cervical lordosis is a rare but serious complication after cervical laminoplasty (CLP), and it is essential to recognize
the risk factors. Previous studies have demonstrated that
greater flexion range of motion (fROM) and smaller ex-Asian Spine Journal
tension ROM (eROM) in the cervical spine are associatedwith the loss of cervical lordosis after CLP. Considering
these facts together, it can be hypothesized that an indicator representing the gap between fROM and eROM
(gROM) is a highly useful in predicting postoperative cervical lordosis loss. The present study aimed to investigate
the risk factors of marked cervical lordosis loss after CLP
for cervical spondylotic myelopathy (CSM), including
gROM as a potential predictor.
Methods: Patients who underwent CLP for CSM weredivided into patients with and without loss of more than
10° of sagittal Cobb angle between C2 and C7 at the final
follow-up period compared to the preoperative measurements (cervical lordosis loss [CLL] group and no CLL[NCLL] group, respectively). Demographic characteristics, surgical information, preoperative radiographic measurements, and posterior paraspinal muscle morphology
evaluated by magnetic resonance imaging were compared
between the two groups. The fROM and eROM were examined on the neutral and flexion-extension views of lateral radiography; gROM was calculated using the following formula: gROM (°)=fROM–eROM. The performanceof variables in discriminating between the CLL and NCLL
groups was assessed using the receiver operator characteristic (ROC) curve.
Results: This study included 111 patients (mean age,
68.3 years; 61.3% male), with 10 and 101 patients in the
CLL and NCLL groups, respectively. Univariate analyses
showed that fROM and gROM were significantly greaterin the CLL group than in the NCLL group (40.2° vs. 26.6°,
p<0.001; 31.6° vs. 14.3°, p<0.001, respectively). ROC curve
analyses revealed that both fROM and gROM had excellent discriminating capacities; gROM was likely to have ahigher area under the curve than fROM (0.906 vs. 0.860,
p=0.094), with an optimal cutoff value of 27°.
Conclusions: The gROM is a highly useful indicator forpredicting a marked loss of cervical lordosis after CLP.
For CSM patients with preoperative gROM exceeding
30°, CLP should be carefully considered, since kyphoticchanges can develop postoperatively.

S11

PS-FP-1-14

Decompression Status of the Spinal Cord
after Cervical Laminoplasty in Various Body
Positions and Neck Postures Observed Using
Percutaneous Ultrasonography: Relationshipwith Neurological Recovery
Sachio Hayama, Yoshiharu Nakaya, Atsushi Nakano,Takashi Fujishiro, Toma Yano, Masahiro Mizutani,
Kenta Fujiwara, Masashi Neo
Department of Orthopedic Surgery, Osaka Medical College, Takatsuki,
Japan

Purpose: Percutaneous ultrasonography (PUS) is used toevaluate the status of the spinal cord after cervical laminoplasty (CLP). This technique helps assess real-time movements of the spinal cord and provides immediate information regarding the decompression status. Additionally,
it can also be utilized to evaluate the status of the spinal
cord in various body positions and neck postures. This
study aimed to examine changes in the decompression
status of the spinal cord after CLP for cervical spondylotic
myelopathy (CSM) in different body positions and neckpostures using PUS and to assess whether these decompression statuses are related to clinical outcomes at eachtime point.
Methods: The study included 66 consecutive participants
with CSM who underwent double-door CLP with sutureanchors. PUS was performed postoperatively at 2 weeks,
3 months, 6 months, and 1 year in sitting (neck flexion[Flexion], neutral [Neutral], and extension [Extension])and supine (Supine) positions. The decompression status
was classified into grade I (noncontact), grade II (contact
and apart), and grade III (contact). Clinical outcomes
were evaluated using Japanese Orthopaedic Association(JOA) scores.
Results: The decompression status improved until 3months postoperatively in all body positions and neckpostures and was stable onwards. It changed depending on
body positions and neck postures and was worse in Flexion and better in Supine at all postoperative time points.
Participants with grade I decompression status in Supine
had a significantly better recovery rate of JOA scores after 3 months, 6 months, and 1 year postoperatively thanthose with grade II+III decompression status (p<0.05, all).
However, this significant relationship was not observed inS12Asian Spine J 2021;15(Supplement 1):S1-S177

each sitting position.
Conclusions: The spinal cord after CLP is most decompressed in Supine. Sufficient and continuous restorationof the anterior subarachnoid space in supine position may
indicate positive clinical outcomes after cervical laminoplasty.

PS-FP-1-16

C6 Radiculopathy Can Cause So-Called C5
Palsy: Comparison to C5 Radiculopathy
Takumi Tsubakino, Yasuhisa Tanaka, Takeshi Nakamura,
Yasutaka Naba, Kota Miyake, Eiketsu Kinjo, Shigeaki Kojo
Department of Orthopaedic Surgery, Tohoku Central Hospital, Yamagata,Japan

Purpose: Shoulder girdle paralysis with severe weakness of the deltoid muscles (Deltoid) and biceps brachii
muscles (Biceps) are widely recognized as C5 palsy, while
C6 radiculopathy can also show similar manifestation. In
this study, we compared the characteristics of C6 and C5
radiculopathy in patients with shoulder girdle paralysis.
Methods: A serial series of 27 cases with preoperative
manual muscle testing (MMT) of Deltoid “3” or less who
had got their symptoms improved after single-nerve root
decompression through posterior open foraminotomy
from September 2006 to March 2018, was analyzed retrospectively. The subjects were divided into two groups;
C5 radiculopathy group (group C5) consisted of 23 cases(16 males, 7 females; range, 39–79 years old), and C6 radiculopathy group (group C6) consisted of four cases (twomales, two females; range, 34–64 years old). We investigated (1) initial symptoms, (2) numbness of the upper
limbs at the first visit, (3) preoperative MMT of Deltoid,
Biceps and wrist extensors, (4) biceps tendon reflex (BTR),
and (5) MMT of Deltoid and Biceps 1 year after surgery.
Results: In both groups, suprascapular pain was the initial symptom in all cases. In group C5, six cases had nonumbness and 17 cases on the lateral aspect of the upperarm. In group C6, one case had numbness on the lateral
aspect of the upper and forearm, and three cases on thelateral aspect of the upper limb and thumb. The cases withweaker Deltoid compared to Biceps were found only ingroup C5 (18 cases). In group C6, Biceps was equivalent(two cases) or weaker (two cases) compared to Deltoid.

Wrist extensors were weak in all the cases in group C6,
while no weakness was found in group C5. BTR was diminished in all cases in both groups. MMT of Deltoid andBiceps improved in all cases in both groups after surgery,especially in group C5 with their Biceps improved to “4”or more in all cases. In group C6, the improvement ofDeltoid was better than Biceps.
Conclusions: Severe weakness of the Deltoid should becalled “shoulder girdle paralysis”, not C5 palsy. Common
in C5 and C6 radiculopathy, suprascapular pain is the initial symptom and BTR is diminished, while in C6 radiculopathy, weakness of the Biceps is equivalent or severer
than Deltoid, and weakness of wrist extensors can also be
observed. In our study, the improvement of Deltoid was
better than Biceps after decompression surgery for C6 radiculopathy.

PS-FP-1-17

Posterior Hybrid Technique for Multi-Level
Cervical Spondylotic Myelopathy with
Instability
Hao Zhang, Feng Zeng Guo
Southern Medical University Affiliated People’s Hospital of LongHua,
Shenzhen, China

Purpose: Cervical spondylotic myelopathy (CSM) is themost severe consequence of cervical intervertebral disk
degeneration as well as the leading cause of spinal cord
dysfunction in patients aged >55 years. While the pathoanatomical variation would be the most critical factor forchoosing the treatment of multi-level CSM. Laminoplasty,
laminectomy or combined with instrumented fusion,
which can accomplish the goal to decompress the spinal
cord, restore sagittal alignment, and stabilize the spine.
Here, we present that the posterior hybrid technique‘laminoplasty combined with instrumented fusion’, which
can attain excellent or good improvement for neurologicaloutcomes and quality of life, for the patients with multilevel CSM in different anatomical aetiology.
Methods: This retrospective study included 12 patients(seven males, five females; mean age, 58.6 years) withthree or four-level CSM who had undergone surgery
between May 2014 and December 2018, and who had atleast 3 months of follow-up records. All of patients in-Asian Spine Journal
cluded were diagnosed CSM at more than three level withsegmental instability (C1/2, n=2; C2/3, n=3; C3/4, n=3;
C4/5, n=4), and the need for strong stabilization. The Japanese Orthopaedic Association (JOA) scoring system andVisual Analog Scale (VAS) scores for neck pain were used
to evaluate the clinical results. The cervical sagittal alignment (such as the percentages of slip, slip angle, and C2–7
lordotic angle) of 10 patients with segmental instability at
the C2–7 was measured to evaluate. While the atlas-dens
interval (ADI) of two patients was measured before surgery and at the final followed-up. The occurrence of surgical complications, surgical time, and blood loss volume
were also investigated.
Results: The mean JOA scores before surgery and at final
follow-up were 8.1 and 14.5, respectively. The mean VAS
before surgery was 6.5 and 2.4 at the final follow-up. The
mean C2–7 lordotic angle was 10.5° at the final followup. The mean percentages of slip before surgery were 9.6%
and 3.4% at final follow-up. The mean slip angle was 8.5°
before surgery and 2.2° at the final follow-up. The mean
surgical time was 180.5 minutes. The mean ADI was 5.6
mm before surgery and 3.4 mm after surgery. The mean
blood loss volume was 173.5 mL. There were significant
improvements at final follow-up. All of patients had nocomplications after surgery till final follow-up.
Conclusions: The results suggest that laminoplasty combined with instrumented fusion seem to be effective andsafe surgical procedure for treating CSM with instability.

PS-FP-1-18

The Feasibility Study of Cervical Pedicle
Screwed with a New Individual-Oriented
Template by Three-Dimensional Printing
Technology
Hao Zhang, Wang Zhang
Southern Medical University Affiliate People’s Hospital of LongHua,
Shenzhen, China

Purpose: To establish a new individual-oriented templatefor cervical pedicle screw placement by three-dimensional(3D) printing technology, in order to provide an accurate
and safe method for cervical internal fixation operation.
Methods: Six cases of adult cervical specimens, and64-slice spiral computed tomography (CT) scanning data

S13

were adopted. The 3D digital models of cervical were reconstructed based on the anatomical characteristics of thecervical vertebral lamina. The reverse templates were designed, which reflected accurately morphological featuresof the posterior cervical spine elements. The navigation
modules were obtained with the method of 3D printing,and the direction and depth of the screw channel in theoperation were ensured. Using 3D printing navigation
templates, 24 cervical pedicle screws were inserted. A
postoperative CT scan was used to measure the length ofeach pedicle screw channel and the width of the pedicle
in order to evaluate the relationship between the cervical
pedicle and screw position.
Results: The individual 3D printing navigation templates
can exactly fuse with the cervical vertebral lamina. Postoperative CT data can confirm that 84 screws are placed
entirely within the pedicle. The actual length of pedicle
screw insertion was 100%, and the width of pedicle screw
insertion was up to 94.05%.
Conclusions: The new 3D printing navigation templateof cervical pedicle screw insertion is safe and convenient
during the internal fixation operation, and the accuracy of
cervical pedicle screw implantation can be improved.

PS-FP-1-19

Anterior Cervical Discectomy and Fusion
with Cervical Uncinectomy for Cervical
Radiculopathy with Foraminal Stenosis
Hao Zhang, Feng Zeng Guo
Southern Medical University Affiliate People’s Hospital of LongHua,
Shenzhen, China

Purpose: Cervical radiculopathy is among the most common adult spinal disorders. There are several surgical treatment options available, such as posterior cervical foraminotomy, anterior cervical foraminotomy, anterior cervicaldiscectomy and fusion (ACDF), and cervical disk arthroplasty. This study aims to describe the technique for ACDF
with incomplete or complete uncinectomy for the management of cervical radiculopathy due to foraminal stenosis.
Methods: We retrospectively collected clinical and radiological data from June 2018 to June 2020. A total of 10 patients (16 segments) were included. All patients with cervical radiculopathy due to foraminal stenosis were treated

S14

Asian Spine J 2021;15(Supplement 1):S1-S177

via ACDF with incomplete or complete ipsilateral uncinectomy to achieve complete nerve root decompression.
In total, 16 disc levels (C3/4, 2; C4/5, 4; C5/6, 7; C6/7, 3)
were investigated. The mean follow-up duration was 6.1
months (range, 4.5–19.2 months). The Neck Disability
Index (NDI) and Visual Analog Scale (VAS) scores forneck pain before surgery and at final follow-up were used
to evaluate the clinical results. The occurrence of surgicalcomplications, surgical time, and blood loss volume werealso investigated.
Results: The mean VAS scores before surgery and at final
follow-up were 6.6 and 1.5, respectively. The mean NDI
before surgery was 0.38 and 0.08 at the final follow-up.
The scores decreased significantly at the final follow-up(p<0.01). The mean surgical time and the mean blood loss
volume were 125 minutes and 10 mL, respectively. There
were significant improvements at final follow-up. There
were no vertebral artery injuries, cerebrospinal fluid leaks,
or wound infections. One patient with three-level discectomy suffered dysphagia after surgery, while improved
at final follow-up. All of the patients were decompressed
completely and had a good to excellent outcome.
Conclusions: ACDF with uncinectomy was a safe andeffective procedure that can relieve pain and lead to a
resolution of neurologic symptoms for patients with cervical radiculopathy. Despite completely decompressed thenerve due to bony foraminal stenosis, this technique didwell in the short-term, although longer-term follow-up isrequired.

PS-FP-1-20

Investigation of Diagnostic Imaging Criteria
for Developmental Stenosis Based on CervicalSpondylotic Myelopathy in Young Patients
Tsuyoshi Iida1,2, Narihito Nagoshi2, Satoshi Suzuki2,
Osahiko Tsuji2, Satoshi Nori2, Eijiro Okada2, Mitsuru Yagi2,
Masaya Nakamura2, Morio Matsumoto2, Kota Watanabe2
1

Department of Orthopaedic Surgery, Kitasato University Kitasato InstituteHospital, Tokyo, Japan2
Department of Orthopedic Surgery, Keio University School of Medicine,Tokyo, Japan

Purpose: Cases of cervical spondylotic myelopathy (CSM)with developmental stenosis are commonly observed;
however, diagnostic imaging criteria for this pathology

still remains elusive. In the present study, we used imaging
data of CSM patients who required surgery at young age,compared to demographically matched healthy volunteers, and verified the imaging features of young developmental cervical stenosis.
Methods: A case-control study was performed for CSM
patients who underwent cervical decompression surgery
at our institution under 50 years of age from October2005 to March 2018. After excluding cervical disc herniation with more than 50% occupancy in the spinal canal,
localized osteophytes, yellow ligament ossification, posterior longitudinal ligament ossification, cerebral palsy,
congenital malformations, cervical kyphosis, achondroplasia, dialytic spondyloarthropathy, and peripheral nerve
disease complication cases. Total of 26 cases were selected
as the developmental cervical stenosis (DCS) group. Ageand gender-matched healthy volunteers were selected as
the control group. Torg-Pavlov ratio at C2 to C7 level andlateral mass-to-posterior vertebral body/canal diameter(LM/CD) ratio at C2 to C7 level were evaluated by X-ray
lateral views of cervical spine. Magnetic resonance imaging (MRI)-Pavlov ratio at C2 to C7 level, occupation ratio
at C2 to C7 level, and Nouri’s spinal cord occupation ratio(SCOR) were evaluated by MRI sagittal views of cervicalspine. The receiver operating characteristic (ROC) curve
was constructed and area under the ROC curve (AUC)
was calculated in all imaging parameters.
Results: The mean age at surgery in DCS group was
41.3±7.0 years. Of the enrolled subjects, 18 cases were maleand eight cases were female. At imaging findings, significant differences were observed between the DCS and control groups in Torg-Pavlov ratio at all level (C3 to C7 level)(p<0.001), MRI-Pavlov ratio at all level (p<0.001) and occupation ratio at all level (p<0.001) and SCOR (p<0.001).
A particularly large statistical difference was observed in
the MRI-Pavlov ratio at C4 level (p=9.21×10-11). In ROC
analysis, AUC was the highest in the MRI-Pavlov ratio at
C4 level (AUC=0.925), with a specificity of 96.3% and sensitivity of 81.5% when the cutoff value was 0.560.
Conclusions: Our findings suggested that the MRI-Pavlov
ratio at the C4 level could be a useful indicator of DCS in
young-aged patients who need surgical decompression.

Asian Spine Journal
PS-FP-1-21

Surgical Strategy for the Cervical Kyphosis Patients
Associated with Cervical Spondylolisthesis:
Three Cases’ Experience
Daichi Takahashi1, Akira Matsumura1, Takashi Namikawa1,
Ryo Yanai1, Hiroaki Nakamura2

S15

tients with cervical kyphosis associated with DS. Although
it is a quite small number of cases, we suggested our surgical strategy for the patients with cervical kyphosis associated with DS as follows: (1) anterior interbody fusion andsubsequent posterior fusion for the flexible type, and (2)posterior corrective fusion and subsequent anterior interbody fusion for the rigid type.

1

Department of Orthopedics, Osaka City General Hospital, Osaka, Japan
Department of Orthopedics, Osaka City University, Osaka, Japan

2

Purpose: Surgical strategy for the cervical kyphosis patients associated with cervical spondylolisthesis (degenerative spondylolisthesis, DS) has not yet been established.
We surgically treated three cervical kyphosis patientsassociated with cervical spondylolisthesis. The purposeof this study is to introduce our surgical strategy for thisdisorder.
Methods: We retrospectively reviewed three cervicalkyphosis associated with DS cases (all females; age atsurgery, 48, 73, 77 years; follow-up, 12, 12, 24 months).
All patients underwent combined anterior-posterior spinal fusion. We evaluated the local curve flexibility using
fulcrum backward bending (FBB) films. According to
the curve flexibility, we decided the surgical procedure.
In tow patients who had flexible kyphosis (flexible type),
we performed anterior interbody fusion at first and thenposterior fusion. In a case who had rigid kyphosis (rigidtype), posterior corrective fusion was performed at first
and then anterior interbody fusion. The number of fusedvertebrae were four, three in the flexible type, and nine in
the rigid type, respectively. Radiographic measurements
and clinical outcomes using Japanese Orthopaedic Association (JOA) score were evaluated before and after surgery (preoperative/postoperative).
Results: All patients presented local kyphosis associatedwith C4 slip and cervical myelopathy. Radiographic parameters (preoperative/postoperative) were as follows:
C1–2: 34.7°/29.3°, C2–7: -30.7°/0.3°, C2–7 sagittal verticalaxis: 27.7°/17.3 mm, and local kyphosis: 32.0°/4.7°. FBB
films showed that local kyphosis was 11.5° in the flexible
type, and 34° in the rigid type. The JOA score improved
from 10.7 points to 13.3 points.
Conclusions: Local kyphosis over 13° was critical value forpoor outcome following expansive laminoplasty for thepatients with cervical spondylotic myelopathy. Therefore,
correction of the local kyphosis is mandatory for the pa-

PS-FP-1-24

A Meta-Analysis of the Efficacy of Botulinum
Toxin A and Occupational Therapy versus
Occupational Therapy Alone in Children with
Upper Limb Spastic Cerebral Palsy
Alice Chu1, Anugya Mittal2, Vaishali Ravikumar2,
Kunj Jain2, Yash Shah2, Amy Song2, Lauren Hutnik2,
Anam Purewal3, Sarthak Mohanty4, JenFu Cheng5
1

Division of Pediatric Orthopaedics, Department of Orthopaedic Surgery,
Rutgers-New Jersey Medical School, Newark, NJ, USA
2
Rutgers New Jersey Medical School, Newark, NJ, USA
3
St. George’s University School of Medicine, St. George, Grenada
4
Department of Orthopaedic Surgery, Perelman School of Medicine,
University of Pennsylvania, Philadelphia, PA, USA
5Children’s Specialized Hospital, Rutgers-New Jersey Medical School,
Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ, USA

Purpose: Cerebral palsy (CP) is the most common childhood motor disability with many treatment modalities
aimed at improving limb function, including botulinum
toxin type A (BoNT-A) injections and occupational
therapy (OT). The purpose of this review was to assess theeffect of BoNT-A in conjunction with OT on occupational
performance and quality of upper limb movement in children with CP.
Methods: A literature search was conducted using the Cochrane, PubMed, CIAHL, and Web of Science databases
using the keywords “cerebral palsy”, “upper extremity”,“pediatric”, “hand”, treatment”. Using this database, papers
were identified which included BoNT-A treatment alone
and BoNT-A combined with OT in children between 0
and 18 years. Melbourne Assessment of Unilateral Upper
Limb Function (Melbourne Assessment) and Canadian
Occupational Performance Measure (COPM) were theoutcome measures analyzed at baseline, 3 months, and 6
months using 2-way analysis of variance with Bonferroni’s
Post-Hoc test for multiple comparisons.
Results: Initial literature search yielded 3,855 studies after

S16

Asian Spine J 2021;15(Supplement 1):S1-S177

the removal of duplicates. Of the 3,855 studies that werescreened, a total of eight studies contained mean data forat least one of the outcome measures mentioned above.
While comparing studies where BoNT-A was applied inconjunction with occupational therapy (n=6) versus studies where only BoNT-A injections were given (n=3), there
was no significant difference between baseline COPM
Performance Scores (p=0.9631). However, at 3 months(p<0.001) and 6 months (p<0.001) after treatment, thecombination of BoNT-A with occupational therapy
outperformed BoNT-A alone. The same trend was seen
for COPM Satisfaction Scores at baseline (p=0.5955), 3
months (p<0.001), and 6 months (p<0.001). While thechanges in the Melbourne Assessment were not significant at baseline (p=0.0202), 3 months (p>0.9999), or 6months (p>0.999), studies with BoNT-A alone treatment
had a greater mean increase in scores.
Conclusions: BoNT-A plus OT appears to improve individuals’ COPM outcomes more than BTX-A alone. However, the impact of BoNT-A and OT on the Melbourne
Assessment and other outcome measures must be further
investigated as the results were inconclusive. Anothersystematic review examining the effect of BoNT-A andphysiotherapy versus physiotherapy on lower extremities
found improved outcomes in range of motion (ROM)and spasticity using the Modified Ashworth Scale (MAS).
Therefore, it would be interesting to compare other outcomes measures such as MAS, ROM, and the goal assessment scale.

PS-FP-1-26

Modified Kurukawa Cervical Laminoplasty
Using Iliac Crest Bone Graft as Spacers: Why
to Do It Any Other Way?
Aashish Babanrao Ghodke, David Jaffray, Birender Balain
Robert Jones & Agnes Hunt Orthopaedic Hospital, Oswestry, UK

Purpose: The spinous process splitting laminoplasty wasdescribed by Kurukawa in 1982, although the procedure
has number of theoretical and practical advantages overthe Hirabayashi technique it has not been widely usedbecause of technical difficulties. The theoretical advantageof laminoplasty is that it can preserve the stability of thecervical spine preventing postoperative kyphosis which

can be seen after laminoplasty, and at the same time, it canpreserve motion preventing adjacent segment diseases observed as late sequelae after anterior/posterior (AP) fusion
surgery. Earlier laminoplasty techniques did not preserve
the dynamic stability of the extensor muscles and failed toshow superiority over other techniques. Laminoplasty as
described in our study showed similar neurological improvement to other studies but by preserving the muscle
attachments at C2 and C7 and early postoperative mobilization, showed better stability and better-preserved rangeof motion (ROM) in comparison to earlier studies. Modifications of Kurukawa cervical laminoplasty include splitting spinous process in the midline with a burr, preserving
muscle attachments at C2 and C7, use of iliac crest graft asspacer, and a rigorous postoperative neck ROM exercise
regimen.
Methods: Forty-four patients with cervical myelopathy
with a mean follow-up of 1.4 years. Patient-reported outcome measurements, radiological and clinical parameters,
and complications were evaluated.
Results: Impressive increases were seen in AP canaldimensions, which persisted. Mean modified Japanese
Orthopaedic Association score improved from 11.1 to
13.4 with a recovery rate of 34%. Nurick grade improved
from 3.9 to 2.7 and Neck Disability Index improved by
15%. The mean C2–C7 lordosis angle changed from 18.5°
to 12.0° only, with three patients having loss of lordosisof 20° or more, two clinically doing well and one patientneeding anterior cervical discectomy and fusion for worsening myelopathy, C3/4 instability and pain. Only one
more patient had neck pain and stiffness. Four patients
had a C5-palsy, two improved to grade 5, and two to grade
4. None of the 22 patients had a concomitant foraminotomy at multiple levels had a C5 palsy. No patient hada flat neck deformity. Average operated levels were 3.36
per case. There were a total of 296 hinges created, with
90.5% fully united. Twenty (6.8%) were ununited but undisplaced. Hinges (2.7%) were displaced with no clinicalconcerns. One patient with loose C5 hinge developed aleft C5 palsy 36 hours postoperative despite no compression identified on magnetic resonance imaging scan.
Conclusions: This technique provides excellent clinicaland radiological outcomes, is a safe and inexpensive way
to achieve a good result with a good functional ROM.

Asian Spine Journal
PS-FP-1-27

Preoperative Transverse Area of Spinal
Cord Compression Using Quantitative
Magnetic Resonance Imaging in Surgically
Treated Cervical Spondylotic Myelopathy: A
Descriptive Study
Jon Christian Sanga Manuntag, Lean Angelo Silverio,
Ronald Tangente, Romel L. Tan, Ma Ramona Reyes,
Wencito Daya

S17

both small which mean that the values are representativeof the population.
Conclusions: The TA, CR, and AP diameter are commonly used parameters to measure stenosis in the MRI ofpatients with CSM. These measurements are however not
fully utilized in decision making because of issues of standardization and reproducibility. Here we present values
representative of our Filipino patient in Davao Doctors
Hospital. Prospective analysis can still strengthen theircorrelation to symptoms and increase its significance insurgical decision-making.

Southern Philippines Integrated Neurosurgical Training Program, Davao,
Philippines

Purpose: The purpose of the study was to describe thespecific magnetic resonance imaging (MRI) parametervalues in patients who underwent surgical management
for cervical spondylotic myelopathy (CSM) in Davao
Doctors Hospital from 2012–2018.
Methods: This is a retrospective study that included all patients admitted in the Davao Doctors Hospital from January 2012 to December 2018 for surgically managed CSM.
The demographic and clinical data such as age, gender,
and pre- and immediate postoperative clinical status werereviewed. Names were excluded to keep anonymity. The
specific MRI parameters (transverse area [TA], anteroposterior [AP], compression ratio [CR]) of the patients were
measured by two blinded radiologists and then averaged.
TA is the spinal cord area identified at the site of maximal
compression measured on axial T2-weighted MRI images.
CR is the smallest diameter divided by the transverse diameter of the spinal cord using T2-weighted MRI. AP is
the measurement of the anterior to posterior distance ofthe most stenotic level.
Results: There were a total of thirty patients includedin the study. Majority of the patients were more than 50
years old and male. TA range is 15.65–62.7 mm 2. The
mean is 34.58 mm2 and the median is 34 mm2. The standard deviation is 10.69 and the confidence interval (CI) is
3.89. CR range is from 0.1–0.725. The mean is 0.39 witha standard deviation of 0.11. The median is 0.375. The CI
is 0.04. It is the most precise and reliable of the three MRIparameters collected and hence is most promising for future prospective research. AP range for our patients was
1.75–7.3 mm. The mean and median were 5.22 mm and5.05 mm, respectively. The standard deviation is 1.3 andthe 95% CI was 0.47. The standard deviation and CI are

PS-FP-1-28

Impact of Cervical Alignment for Prognosis ofCervical Spondylotic Amyotrophy: Propensity
Score Matching Analysis
Masahito Takahashi1, Masaaki Tsuji1, Kazuhiko Satomi2,
Takumi Takeuchi1, Hideto Sano1, Shoichi Ichimura1,
Naobumi Hosogane1
1

Department of Orthopedic Surgery, Kyorin University, Mitaka, Japan
Orthopedic Surgery, Mitaka Hospital, Mitaka, Japan

2

Purpose: Cervical spondylotic amyotrophy (CSA), involving dissociated motor loss in the upper extremities,
is considered as the stage prior to cervical spondylotic
myelopathy (CSM). In some cases of CSA, the symptom
has a self-limited natural history. However, the factors associated with the natural history of recovery of CSA havenot been reported in the literature. The concept of cervicalalignment parameters is recognized over time, and theseparameters are implied to be correlated with the healthrelated quality of life outcomes and pathogenesis of CSM.
The purpose of this study was to investigate the impact of
cervical sagittal alignment parameters on the prognosis of
CSA using propensity score matching analysis.
Methods: Retrospective cohort study. Patients with proximal CSA who were followed conservatory over 6 months
from the onset, had a manual muscle test (MMT) score<3, and had confirmed denervation potentials in the deltoid and/or biceps brachii muscles on electromyography
were eligible. Patients with diabetes mellitus, a rotator cuff
tear, encephalopathy, or a neuromuscular disease were excluded. Age, sex, MMT score, cervical lordosis, number ofstenosis levels, and existence of T2-weighted high-intensi-

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Asian Spine J 2021;15(Supplement 1):S1-S177

ty area (T2HIA) in the spinal cord on magnetic resonanceimaging (MRI) were investigated. The patients were divided into two groups, recovery and non-recovery group,
and a propensity score matching analysis was conducted
to examine the prognostic factors of proximal CSA.
Results: A total of 127 patients were diagnosed with proximal type of CSA in our department. Eligible patients were31, 18 in recovery group and 13 in non-recovery group.
The mean degree of cervical lordosis (CL) was significantly lower in non-recovery group (10.2 vs. -2.3, p<0.01).
The mean number of levels of stenosis on MRI was 2.5
and 3.0 in recovery group and in non-recovery group,
respectively. The number of patients having C3/4 stenosis
was seven (38.9%) in recovery group and nine (69.2%)
in non-recovery group, with tendency to be higher incidence in non-recovery group (p=0.07). Only one patient
in recovery group had T2HIA on MRI. Twenty-four of
31 patients were matched in a one-to-one ratio in the twogroups. Propensity score matching showed that CL was anindependent predictor of recovery of CSA (odds ratio, 1.2;
95% confidence interval, 1.02–1.34; p<0.05).
Conclusions: Cervical sagittal alignment parameters had asignificant influence on the natural course of CSA, and CL
might be one of the factors that predict CSA prognosis.

PS-FP-1-29

Usefulness of the Disabilities of the Arm,
Shoulder, and Hand in Evaluating Surgical
Outcome of Cervical Spine Disorders
Nao Otomo1,2, Haruki Funao1,2,3, Kentato Ideura4,
Kento Yamanouchi3, Norihiro Isogai1,2, Yutaka Sasao1,2,
Shigeto Ebata1,3, Ken Ishii1,2,3
1

Department of Orthopaedic Surgery, School of Medicine, International
University of Health and Welfare, Otawara, Japan2
Department of Orthopaedic Surgery, International University of Health andWelfare Mita Hospital, Tokyo, Japan3
Department of Orthopaedic Surgery, International University of Health andWelfare (IUHW) Narita Hospital, Narita, Japan
4
Department of Rehabilitation, International University of Health andWelfare Mita Hospital, Tokyo, Japan

Purpose: Patients with cervical spine disorders may present with upper extremity symptoms including numbness,
motor weakness and hand clumsiness, and often havesome sort of trouble in activities of daily living (ADL).
The disabilities of the arm, shoulder, and hand (DASH)

is a patient-reported questionnaire designed to measurefunctional disability due to upper extremity conditions.
Although the DASH is commonly applied to evaluate
ADL in patients with rheumatoid arthritis and entrapment neuropathies in the upper extremity, there are very
few reports in cervical spine disorders. The purpose ofthis study was to examine the usefulness of the DASH in
evaluating surgical outcome of cervical spine disorders.
Methods: Fifty-seven consecutive patients who underwent
surgery for cervical spine disorders were included in thisstudy. They consisted of 35 men and 22 women, and theirmean age at the time of surgery was 59.7±13.3 years old.
The DASH score and the Japanese Orthopaedic Association (JOA) score were collected preoperatively and at 6
months postoperatively. The changes of the JOA score andthe DASH score at the time of operations and 6 months
after surgery were examined. The statistical association
between the JOA score and the DASH score was also evaluated. By the analysis of the patients’ replies to the DASH,
it was also clarified what kind of activities recovered after
surgery.
Results: The JOA score and the DASH score were 12.7±2.5
and 21.9±17.4 at the time of operations, and 15.6±1.4 and
16.1±14.1 at 6 months postoperatively. The JOA score andthe DASH score significantly improved from baseline to 6
months after surgery (p<0.01). There were significant negative correlations between the JOA score and the DASH
score at the time of operation (r=-0.415, p<0.01) and 6
months after surgery (r=-0.312, p=0.02). The DASH itemof carrying heavy stuff was improved in 35.2%, and thoseof the recreational activities requiring muscular strengthof upper extremities improved in 51.9% patients.
Conclusions: In this study, we found a significant correlation between the JOA score and the DASH score inpatients with cervical spine disorders. The DASH scoring
system would be useful in evaluating surgical outcome ofcervical spine disorders, and it could reflect on upper extremity function and ADL in more detail.

Asian Spine Journal
PS-FP-1-30

The Posterolaterally Oriented and Laterally
Downward Sloping Facet Joint Is a Risk Factor
for Degenerative Cervical Spondylolisthesis
and Myelopathy
Hiromi Kumamaru1, Takeyuki Saito1, Shingo Yoshizaki1,
Yasuharu Nakashima2, Katsumi Harimaya1
1

Department of Orthopedic Surgery, Kyushu University Beppu Hospital,
Beppu, Japan2
Department of Orthopedic Surgery, Graduate School of Medical Sciences,
Kyushu University, Fukuoka, Japan

Facet joints are crucial anatomical structures in determining spinal biomechanical motion, but the potential relationship between facet orientation and the developmentof cervical spondylolisthesis remains unclear. To explore
the relationship between facet orientation and cervicalspondylolisthesis as well as myelopathy. Facet orientation in the cervical spine was studied using computed
tomography in 105 patients with cervical myelopathy, andthe facet inclination was measured on axial, coronal, andsagittal reconstructed images. The subjects were divided
into anterolisthesis, retrolisthesis, and no spondylolisthesis groups at each intervertebral level (C2/3–C6/7).
The below facet joints of the posterior or anterior slippedvertebral bodies tend to slope posterolaterally and downward laterally compared to non-slipped vertebral bodies
from C3/4 to C5/6 level. The posterolaterally oriented andlaterally downward sloping facet at C3/4 and C4/5 levels
would be a risk factor for the development of cervicalspondylolisthesis as well as symptomatic myelopathy.

PS-FP-1-33

Accuracy of the Adjustable Aiming Device
for Caspar Pin Insertion in Anterior Cervical
Spine Surgery: Human Cadaveric Study
Torphong Bunmaprasert, Raphi Raphitphan,
Nantawit Sugandhavesa, Wongthawat Liawrungrueang
Department of Orthopaedics, Chiang Mai University, Chiang Mai, Thailand

Purpose: Rectangular shape of disc space preparation during anterior cervical discectomy and fusion or cervical

S19

disc replacement is a desirable goal. Proper insertion of
the vertebral distraction or Caspar pin can provide rectangular disc space by putting the pins parallel to the indexed
vertebral endplates. Traditional free-hand technique may
require multiple insertion attempts that may compromise
the vertebral body and increase radiation exposure during pin localization. No published study has reported themethod of creating parallel Caspar pin insertion without intraoperative fluoroscopy. The purpose is to study
whether the novel adjustable Caspar pin aiming device
provides the accuracy and safety for Caspar pin insertionin anterior cervical procedures.
Methods: Forty Caspar pins were placed through the adjustable Caspar pin aiming device in 20 human cadaveric
cervical vertebral bodies from C3 to C7 after performing
anterior discectomies. The parameters of pin insertion
were evaluated by lateral fluoroscopy, including superior
endplate slope (SE), inferior endplate slope (IE), Caspar
pin slope (CP), and endplate-Caspar pin slope difference(SE/CP, IE/CP). The accuracy of pins was assessed by determining the difference of slope between vertebral endplates and Caspar pin, while considering the difference
less than 5º was acceptable.
Results: Five cadaveric specimens, with an average ageof 67.2 years, were utilized in the study. The mean SE, IE,
and CP were 10.82°±2.3°, 10.32°±3.2°, and 15.58°±7.9°(p<0.0001), respectively. The average SE/CP difference and
IE/CP difference were 6.6°±0.8° and 7.7°±0.8° (p=0.35),
respectively. The most slope difference was observed at SE
and IE of C3. No cervical endplate violations occurred.
Conclusions: In a cadaver model, the adjustable Caspar
pin aiming device provides high accuracy for Caspar
pin placement with the average endplate–CP difference
less than 7.7°. This creates placement of the superior andinferior Caspar pins parallel to the indexed vertebral
endplates. Furthermore, it may facilitate safe and effective
insertion of Caspar pins in anterior cervical procedures.
However, pin placement at C3 vertebral body should bedone and adjusted carefully through this device.

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Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-1-34

The Natural History of Patients with Cervical
Radiculopathy Treated Conservatively andCorrelating with Clinical and Magnetic
Resonance Imaging Features after a Mean
Follow-up of 33 Months
Gowtham Ranga Sai Jallipalli, Saumyajit Basu
Department of Spine Surgery, Kothari Medical Center, Kolkata, India

Purpose: Few published studies have focused solely on
clinical outcomes after conservative treatment. Selection of study population was not homogenous often
myelopathy and radiculopathy patients were clubbed andsome studies used variety of treatment options including steroids injections and root blocks. The present study
attempts to evaluate the clinical and radiological natural
history of cervical radiculopathy managed conservatively.
Methods: Patients of acute cervical radiculopathy withsingle level disc herniation presenting to our institution
from Jan 2012 to Dec 2018 were enrolled in the study.
Total of 46 patients were included in the study. With 32
males and 14 females, average age of 42.9 years (range,
25–80 years), mean follow-up period of 33 months (range,
18–58 months). All patients were managed only with
analgesics and pregabalin along with physical therapy inform of transcutaneous electric nerve stimulation. At boththe index visit and follow-up visit, the functional assessment tool used was Neck Disability Index (NDI), Visual
Analog Scale (VAS) scoring was used to assess the severity of neck and arm pain, and Patient-Specific Functional
Scale was used to measure the satisfaction level of patientson follow-up. Grading done in magnetic resonance imaging (MRI) for disc degeneration using Miyazaki Score andneural foraminal stenosis (NFS) was graded using Kim’s
Score. Paired Student t-test was used to compare index
and follow up NDI scores and VAS scores. Inter-observer
reliability was calculated using Cohen’s kappa coefficient.
Correlation between clinical and radiological parameters
was studied by use of Pearson’s coefficient.
Results: The distribution of studied disc levels was 21 at
C6–7 level, 22 at C5–6, and three at C4–5 level. At presentation, neck pain and arm pain were present in all the patients with average VAS scores of 6 and 8, respectively. NDI
scores at this initial evaluation ranged from 20–90 with amean value of 56.75. Clinical evaluation at follow-up re-vealed good relief of neck pain and arm pain. Mean VAS
score improved to 2 and 1.3, respectively at follow-up. Thischange was statistically significant (p<0.001). NDI scoreshowed statistically significant improvement to a mean of
14.23 (range, 0–42.2; p<0.001). NFS grade for the involvedside decreased from an average of 1.52 to 1.08 (p<0.001).
Miyazaki scores changed from 3.20 and 3.35 (p=0.823).
Conclusions: Clinical improvement was seen as a rule incervical radiculopathy patients. MRI showed statisticallysignificant regression of neural foraminal stenosis on follow up. However, correlation between the two could not
be proved.

PS-FP-1-35

Is Cervical Posterior Fixation Effective for
Neck Pain?
Takeo Furuya1, Satoshi Maki1, Sho Okimatsu1,
Takaki Inoue1, Atsushi Yunde1, Masataka Miura1,
Gundong Kim1, Yasuhiro Shiga1, Kazuhide Inage1,
Sumihisa Orita1, Yawara Eguchi1, Masao Koda1,2,
Masashi Yamazaki1,2, Seiji Ohtori1
1

Department of Orthopaedic Surgery, Chiba University Graduate School of
Medicine, Chiba, Japan2
Department of Orthopedic Surgery, Faculty of Medicine, University ofTsukuba, Tsukuba, Japan

Purpose: One of the chief complaints of cervical spine disease is neck pain and shoulder stiffness. Usefulness of surgery, especially fixation surgery, for neck pain is unclear.
The purpose of this study was to evaluate the improvement of neck pain by posterior surgery in patients withcervical myelopathy. And we also evaluated whether the
additional posterior fixation contributes to the improvement of neck pain or not.
Methods: We selected patients with cervical myelopathy
who underwent cervical posterior surgery in our institute from 2009 to 2018. One hundred and eighteen cases
were finally enrolled in this study. We divided those cases
into two groups. One was decompression only group(laminoplasty [LM] group, 81 cases) and the other was
decompression with instrumented fusion group (posterior
decompression with instrumented fusion [PDF] group,
37 cases). We compared preoperative and postoperative
Visual Analog Scale (VAS) of neck pain and postoperative
Neck Disability Index (NDI) in both groups.

Asian Spine Journal
Results: Neck pain VAS in LM group was 47 mm before
surgery and 28 mm after surgery in average (p<0.0002).
Neck pain VAS in PDF group was 47 mm before surgery
and 32 mm after surgery (p=0.07). A statistical evaluation
showed that neck pain was reduced after surgery in LM
group. The amount of change in neck pain VAS before andafter surgery was compared between the two groups: 20
mm in the LM group and 15 mm in the PDF group, withno difference between the two groups. The ratio of postoperative reduction in neck pain was compared between
the two groups: 60% of cases in the LM group had lessneck pain than before surgery. As well, 49% of patients in
the PDF group had less pain than preoperatively. Analysis
in the subgroup of pain intensity of NDI showed no statistically significant difference between the two groups.
Conclusions: Both groups showed improvement or atendency toward improvement in postoperative neck
pain. However, the superiority of additional fixation was
not obvious. Because the mechanism of improving neckpain after surgery might be different in two groups, theinterpretation of the results requires further study. The advantage of this study was that there was no considerationof the presence of neck pain in the selection of surgicalprocedures. Improvement in postoperative neck pain wasachieved in 60% of patients with posterior decompression
surgery and in 49% of patients with posterior decompression with instrumented fusion. The superiority of the additional fixation was not clear in this study.

PS-FP-1-36

Incidence, Prevalence, and ClinicalSignificance of Modic Changes in Cervical
Spine: A Prospective Study
Dilip Chand Raja Soundararajan, Hemanth Kumar Arasavalli,
Ajoy Prasad Shetty, Rishi Mugesh Kanna,Rajasekaran Shanmuganathan
Department of Spine Surgery, Ganga Hospital, Coimbatore, India

Purpose: Modic changes are widely debated on etiology
and pathomechanisms. They have been extensively analyzed in lumbar intervertebral discs. However, there arelimited studies on the prevalence and patterns of Modicchanges in the cervical spine as compared to the lumbar
spine. More importantly, their association with spinal
pain, disc level, age, the severity of disc degeneration,

S21

endplate damage, and sagittal parameters like presenceor absence of kyphosis, T1 slope and C2–C7 angle, andL1–S1 angle has not been analyzed so far. This study was
primarily aimed to investigate the epidemiology of Modicchanges in patients with neck pain and identify probableassociation between Modic changes with disc degeneration, endplate damage, and sagittal parameters.
Methods: The study sample was segregated into threegroups: patients primarily presenting to the outpatient
department with chronic unresolved neck pain (groupA), back pain (group B), and control magnetic resonanceimaging was obtained from patients who were admitted
for spinal trauma (group C). Patients with pathological lesions, such as tumors, infection, congenital abnormalities,
and surgical fusions were excluded. Demographic andclinical parameters like age, sex, duration of symptoms,presence or absence of spinal pain, and severity of pain
(Visual Analog Scale score) were documented. Radiologically parameters evaluated include presence and type of
Modic changes, disc level, disc degeneration (Pfirmann
grade), endplate damage (total endplate score), and sagittal parameters. A case-control analysis for the outcome of
Modic changes was performed.
Results: The overall prevalence of Modic changes in lumbar spine (41%) was higher than cervical spine (16%).
Both cervical and lumbar Modic changes were morecommon in symptomatic than asymptomatic individuals.
While C6–C7 was the most common disc level involved
with Modic changes in symptomatic individuals, C5–C6
was the most common level in patients presenting withback pain. L5–S1 was most common disc level involved insymptomatic individuals and L4–L5 was the commonest
involvement in patients presenting with neck pain. Type
2 Modic changes were most common, followed by type 1
and lastly, type 3 irrespective of the study groups. Patientswith Modic changes had higher intensity of pain, higher
grades of disc degeneration and endplate damage compared to patients without Modic changes.
Conclusions: Our study showed the Modic changes are
more common in the lumbar spine than the cervicalspine, and common in symptomatic individuals. Patientswith Modic changes have a higher intensity of pain, higher
grades of disc degeneration and associated endplate damage, and their presence is more common in non-kyphotic
individuals than kyphotic individuals.

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Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-1-37

Efficacy of Ultrasound-Guided Nerve Root Blockfor Cervical Spondylotic C6 Radiculopathy
Shinichi Ishihara
Department of Orthopaedic Surgery, Ota Memorial Hospital, Gunma, Japan

Purpose: Cervical spondylotic radiculopathy (CSR) is
commonly experienced in clinical practice; however, it isoften difficult to treat because the pain is usually severe
and activities of daily living disability can be serious.
Though nerve root blocks (NRB) are sometimes performed using fluoroscopy for intractable root symptoms,
complications such as vertebral artery injury are feared.
Recently, the widespread of musculoskeletal ultrasoundecho has made it possible to safely carry out cervical NRB.
The purpose of this study is to examine the effectivenessof ultrasound-guided NRB for CSR.
Methods: We retrospectively reviewed sixteen patients(12 males and four females) who were diagnosed with C6
CSR and underwent ultrasound-guided NRB between
April 2018 and July 2019. Xylocaine (0.1%) was used for
NRB, and both ultrasound and fluoroscopy were used in
all cases. First, we investigated which areas of peri-scapulaand upper limb had symptoms: peri-scapula (upper part,
body part, intermediate part) and upper limb (upperarm radial side, from the radial side of the forearm to thethumb, from the forearm ulnar side to the little finger,
upper ulnar side). Next, the Visual Analog Scale (VAS)
scores were evaluated before NRB, immediately after
NRB, and 1 month or more after NRB. Finally, the final
outcomes (improvement: no need for NRB; no change:
continued NRB or not desired; surgery) were examined.
Results: Symptoms appeared in peri-scapula (upper part:
15 cases, inter mediate part: one case) and upper limb
(upper arm radial side: 10 cases, from the radial side of
the forearm to the thumb: six cases, from the forearm
ulnar side to the little finger: one case, upper ulnar side:
one case) (including duplication). The VAS scores were
77.5±13.0 mm (range, 50–90 mm) before NRB, 15.0±14.4mm (range, 0–40 mm) immediately after NRB, and26.3±17.9 mm (range, 10–70 mm) over 1 month, showing
significant improvement compared to before NRB. The final outcomes were improvement (12 patients), no change(two patients), and surgery (two patients). No adverse
events were observed with NRB in all patients.

Conclusions: Treatment of CSR is often difficult withmedication alone, so surgery is often performed. Although minimally invasive surgery using full-endoscope
has recently become available, avoiding surgery is clearlyin the patient’s best benefit, and ultrasound-guided NRB,
which can be performed safely, can be an effective treatment method.

PS-FP-2-1

Spinal Column Phenotypes with Lumbar
Developmental Spinal Stenosis:Results from
2,387 Magnetic Resonance Imaging
Jason Pui Yin Cheung1, Prudence Wing Hang Cheung1,
Dino Samartzis2, Jaro Karppinen3, Kenneth Cheung1,
Marcus Kin Long Lai1
1

Department of Orthopaedics and Traumatology, The University of Hong
Kong, Hong Kong
2
Department of Orthopedic Surgery, Rush University Medical Center,
Chicago, IL, USA
3
Medical Research Center Oulu, Oulu University Hospital and University ofOulu, Oulu, Finland

Purpose: Lumbar developmental spinal stenosis (DSS) is
an imaging phenotype appearing as a shortened anteroposterior (AP) vertebral canal diameter at multiple levels.
It is likely a result of maldevelopment of the spinal canal.
The relationship of canal narrowing with other radiological parameters in the spinal column is unknown.
Methods: This was a radiological analysis of 2,387 subjects who underwent L1–S1 magnetic resonance imaging(MRI). Means and ranges were calculated for their age,gender, body mass index, and MRI measurements. AP
vertebral canal diameters were utilized to differentiatecases of DSS from controls. Other imaging parameters
included the vertebral body dimensions, spinal canaldimensions, disc degeneration scores, and facet joint orientation. Mann-Whitney U-test and chi-square test wereconducted to search for measurement differences between
cases and controls. To identify possible associations between DSS and MRI parameters, parameters that were
statistically significant in the univariate binary logistic regression were included in a multivariate stepwise logistic
regression after adjusting for subject demographics.
Results: Axial AP vertebral canal diameter, interpediculardistance, AP dural sac diameter, lamina angle, and sagit-

Asian Spine Journal
tal mid-vertebral body height were significantly different
between cases and controls (all p<0.05). Narrower interpedicular distance and AP dural sac diameter were associated with DSS (odds ratio [OR], 0.506–0.745; p=0.001–
0.002). Lamina angle (OR, 1.127; p=0.002) and right facet
joint angulation (OR, 0.022; p=0.002) were also associatedwith DSS. No association was observed between disc parameters and DSS.
Conclusions: From this large-scale cohort, the canal size
is found to be independent of subject body habitus. Other
than spinal canal dimensions, abnormal orientations oflamina angle and facet joint angulation may also be a
result of developmental variations, leading to increased
likelihood of DSS. Other skeletal parameters are spared.
Besides, there is no relationship between DSS and soft tissue changes of the spinal column, which suggested DSS isa unique result of bony maldevelopment. Findings should
be validated in other ethnicities and populations.

PS-FP-2-2

Increased Population Risk of Radicular Leg
Pain in Lumbar Developmental Spinal Stenosis
Jason Pui Yin Cheung1, Prudence Wing Hang Cheung1,
Dino Samartzis2, Jaro Karppinen3, Kenneth Cheung1,
Marcus Kin Long Lai1

anteroposterior (AP) vertebral canal diameter, spondylolisthesis, and other MRI phenotypes was assessed. MannWhitney U-test and chi-square test were conducted tosearch for differences between subjects with and without
DSS. Associations of LBP and radicular pain in the pastmonth and the past year with the clinical and radiologicalinformation were also investigated by utilizing univariate
and multivariate logistic regressions.
Results: Of the 2,206 subjects, 153 had DSS. Subjects with
DSS had higher prevalence of radicular leg pain, more
pain-related disability and lower quality of life (all p<0.05).
Subjects with DSS had 1.5 (95% confidence interval [CI],1.0–2.1; p=0.027) and 1.8 (95% CI, 1.3–2.6; p=0.001)
times higher odds of having radicular leg pain in the pastmonth and the past year, respectively. However, DSS was
not associated with LBP. Instead, subjects with spondylolisthesis had 1.7 (95% CI, 1.1–2.5; p=0.011) and 2.0 (95%CI, 1.2–3.2; p=0.008) times more likely to experience LBP
in the past month and the past year, respectively.
Conclusions: This large-scale study identified DSS as anindependent risk factor of acute and chronic radicular leg
pain, and worse disability. DSS is a predictor of radicular
pain, and spondylolisthesis is a predictor of LBP. Thereis an increased likelihood of nerve root compression due
to a pre-existing narrowed canal. These subjects are also
more likely to have poorer disability and quality of life.

Department of Orthopaedics and Traumatology, The University of Hong
Kong, Hong Kong
2
Department of Orthopedic Surgery, Rush University Medical Center,
Chicago, IL, USA
3
Medical Research Center Oulu, Oulu University Hospital and University ofOulu, Oulu, Finland

PS-FP-2-3

Purpose: Low back pain (LBP) and radiating leg pain are
two common health problems around the world. Lumbar
developmental spinal stenosis (DSS) may play an important role in pain generation. It is described as pre- existing
narrowed vertebral canals at multiple lumbar levels withearlier onset of neurological compromise. Therefore, thisstudy was designed to assess the interaction of DSS anddifferent radiological phenotypes in producing LBP, radiating leg pain and disability.
Methods: This was a population-based study of 2,206
subjects with L1–S1 axial and sagittal magnetic resonanceimaging (MRI). Clinical and radiological information regarding subjects’ demographics, workload, smoking habit,

Young-Hoon Kim, Sang-Il Kim, Hun-Chul Kim

1

S23

Effects of Bone Cement Augmentation forUpper Instrumented Vertebra on Adjacent
Segment Degeneration in Lumbar Fusions
Department of Orthopedic Surgery, Seoul St. Mary’s Hospital, College ofMedicine, The Catholic University of Korea, Seoul, Korea

Purpose: This study aims to investigate the long-term effects of bone cement-augmented instrumentation in multilevel lumbar fusions. Cement-augmented screw is one of
the techniques used to reduce early mechanical failure in
multilevel lumbar fusion, especially in the elderly. However, there is little information regarding the long-term
effects.
Methods: Fifty patients who underwent more than threelevels of lumbar fusion were divided into two groups

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Asian Spine J 2021;15(Supplement 1):S1-S177

according to bone cement-augmented screw fixation
involving the upper instrumented vertebra (UIV): 21 patients (cemented group, group 1) and 29 patients (noncemented group, group 2). The analysis of radiographic
adjacent segment degeneration (ASD) involved patientswith lumbosacral fusion showing a similar degree of osteoporosis. Radiologic ASD was defined as more than two
UCLA grades of progression at 2 years postoperatively.
Other sagittal parameters were analyzed such as pelvic
incidence-lumbar lordosis (PI–LL) and preoperative magnetic resonance Pfirrmann grades for adjacent level, probably related to ASD.
Results: Even when no significant differences existed in
preoperative demographic and radiographic parameters
between the two groups, the postoperative kyphoticchanges at 3 months were higher in the non-cemented
group. In terms of long-term effects, radiologic ASD(20 patients [95.2%] in group 1; 15 [53.6%] in group 2)
was significantly higher in the cemented group. Logistic
regression analysis of radiologic ASD including otherclinical and radiological parameters, postoperative PI–LL
mismatch (odds ratio [OR], 5.201; 95% CI, 1.123–24.090;
p=0.035), and cement augmentation (OR, 20.193; 95% CI,
2.195–185.729; p=0.008) showed a significant correlation
with the development of radiologic ASD at postoperative
2 years.
Conclusions: Although bone cement-augmented screw
implantation can prevent kyphotic deformation at theproximal junction of UIV in early postoperative stages ofmulti-level lumbar fusion, a discreet selection of patientsis required due to possible accelerated degeneration of adjacent segments.

PS-FP-2-5

The Problems and Measures of L5 Osteotomy
Takashi Kobayashi1, Kazuma Kikuchi1, Hayato Kinoshita1,
Ryota Kimura1, Eiji Abe1, Hajime Murai1, Natsuo Konishi1,
Takahiro Sato1, Yoichi Shimada2, Naohisa Miyakoshi2
1

Department of Orthopedic Surgery, Akita Kousei Medical Center, Akita,Japan
2
Department of Orthopedic Surgery, Akita Univercity School of Medicine,
Akita, Japan

Purpose: To clarify the problems of L5 osteotomy and todescribe the countermeasures.

Methods: Twelve cases of L5 osteotomy were reviewed:
seven cases of osteoporotic vertebral body fracture (OVF),
three cases of kyphosis after fixation, including L5, onecase of distal junctional failure, and one case of spontaneous fusion of degenerative spondylolisthesis. The OVF
was classified as type A with compression of the cephalocaudal endplate, type B with compression of the cephaladendplate only, and type C with compression of the caudal
endplate, and vertebral column resection was performed
for A, L4/5 posterior lumbar interbody fusion (PLIF) for
B, and L5/S PLIF for C. For other kyphosis cases, pedicle
subtraction osteotomy was performed at L5. The range offixation was from the thoracic spine to the pelvis in ninecases and from the lumbar spine to the pelvis in threecases. The caudal anchor was S2-alar-iliac (S2AI) screws
in all cases.
Results: The age at surgery was 73.1±6.2 years for OVF
and 73.0±5.8 years for kyphosis. Two cases of OVF weremale, and the other 10 cases were female. The operative
time was 280±45 minutes for OVF and 413±60 minutes(p=0.001) for other kyphosis cases, and the blood loss was625±635 g for OVF and 903±297 g for kyphosis cases. All
three cases of OVF type A and one case of kyphosis developed postoperative neurological symptoms in the lower
extremities, and one case of type A required reoperation
due to early postoperative instrumentation failure. One
type B patient developed surgical site infection, and one
kyphosis patient developed rod fracture 7 months after
surgery and required reoperation. In two of the three cases, the upper end of the fixed lumbar vertebrae had instrumentation failure. The radiographic alignment of sagittal
vertical axis, pelvic tilt, and lumbar lordosis improved,
and Oswestry Disability Index also improved significantly
at the last follow-up.
Conclusions: Osteotomy of the L5 vertebra can be useful if the patient has kyphosis due to a fracture of the L5
vertebra or kyphosis in the lower lumbar spine due to inadequate fusion surgery. However, the L5 vertebral bodyhas some problems, such as a large transverse processthat makes osteotomy difficult, few caudal anchors, anda strong ligament that makes shortening difficult. In thiscase, a preoperative computed tomography scan of thebone morphology, use of the S2AI screws as a caudal anchor, and selection of appropriate osteotomy can be useful
options.

Asian Spine Journal
PS-FP-2-7

Spinal Endoscopic-Full See Technique for
the Treatment of Two-Level Lumbar Lateral
Recess Stenosis
En Song1, Ji Zheng Li2, Yan Lin Li1, You Qing Huang3,
Fan Bing Li2, Xiao Feng Yuan4, Xue Song Chen5,
En Bin Wang6, Xian Guang Yang1, Yao Yu Xiang1

S25

preoperative ODI score was 72.4±1.2, while postoperative
1 months, 3 months, and final follow-up ODI scores were28.5±3.9, 22.6±4.1, and 12.5±3.3, respectively (p<0.001).
Conclusions: Spinal endoscopic-full see technique for thetreatment of two-level lumbar lateral recess stenosis is aneasy, safe, and effective minimally invasive surgery for patients with lumbar spinal stenosis. But this technique has
a “long and steep” learning curve.

1

Department of Sports Medicine, The First Affiliated Hospital of Kunming
Medical University, Kunming, China
2
Department of Orthopedics, First Clinical Medical College of Yunnan
University of Traditional Chinese Medicine, Kunming, China
3
Department of Pain, The Second Affiliated Hospital of Kunming Medical
University, Kunming, China
4
Department of Orthopedics, The First People’s Hospital of Kunming,
Kunming, China
5
Department of Pain, The Fourth People’s Hospital of Kunming, Kunming,
China
6
Department of Orthopedics, Baoshan Hospital of Traditional Chinese
Medicine, Shanghai, China

Purpose: Lumbar spinal stenosis is a common lumbar
vertebrae disease in the elderly population, can lead toleg pain and low back pain especially when walking. The
spinal endoscopic-full see technique used the novel endoscopic instruments and equipments for the decompressionof spinal stenosis. This study aimed to evaluate the safety
and curative effect of this new technique for the treatmentof two-level lumbar spinal lateral recess stenosis.
Methods: From August 2018 to August 2019, this retrospective study recruited 21 patients with two-level lumbar
spinal stenosis who underwent spinal endoscopic-full
see technique via the surgical approach of the posterolateral intervertebral foramen, used the outer endoscopic
reamer, full endoscopic bone chisel, and rongeur for foraminotomy and lateral recess stenosis decompression.
The postoperation neurological function and pain status
were evaluated by the Visual Analog Scale (VAS) score ofpain and the Oswestry Disability Index (ODI). The data,
including preoperative comorbidities, operation time, thequantity of bleeding, bed rest time, and intraoperative andpostoperative complications, were recorded.
Results: The mean operation time was 100 minutes; themean quantity of bleeding was 30 mL. All patients were
followed-up for 4 months to 1 years. The mean preoperative VAS score was 7.3±1.3, while postoperative 1 months,
3 months, and final follow-up VAS scores were 1.8±0.7,
1.1±0.6, and 0.8±0.6, respectively (p<0.001). The mean

PS-FP-2-12

The Role of Gut-Skin-Spine Axis in the Establishment and Evolution of Human Intervertebral
Disc Microbiome and Degenerative Disc
DiseaseDilip Chand Raja Soundararajan1, S. Rajasekaran1,
Sharon Miracle Nayagam2, Tangavel Chitraa2,
K. S. Sri Vijayanand1, Muthurajan Raveendran3,
Shetty AJoy Prasad1, Kanna Rishi Mugesh1
1

Department of Spine Surgery, Ganga Hospital, Coimbatore, India
Department of Proteomics, Ganga Research Centre, Coimbatore, India
3
Department of Plant Biotechnology, Tamil Nadu Agricultural University,
Coimbatore, India
2

Purpose: Microbial etiology has been recently postulated
as a cause of degenerative disc disease (DDD) leading torandomized trials of probiotics and antibiotics to treat
chronic low back pain. However, the exact bacterial etiology has not been investigated. This study was conducted
to trace the origin of the human intervertebral disc (IVD)
microbiome and establish microbial biomarkers for DDD.
Methods: Healthy lumbar discs (ND) group (26 NP[nucleus pulposus] tissues and 17 EP [cartilaginous endplates]) excised from 10 magnetic resonance imaging normal asymptomatic organ donors underwent metagenomic
analysis. A comparative analysis of the healthy IVD microbiome with that of 21 degenerate discs was performed
to identify biomarkers of DDD. The ND microbiome wasalso compared to that of fetal and adult gut and adult skinmicrobiome to investigate the existence of gut-skin-spine
axis and trace the origin of the human IVD microbiome.
Results: In total, four dominant phyla were detected: Proteobacteria, Firmicutes, Actinobacteriota, and Bacteroidetes. Proteobacteria was identified as the dominant phyla
in both NP and EP disc with 72% and 68% mean relative
abundance respectively. Overall NP and EP had similar

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Asian Spine J 2021;15(Supplement 1):S1-S177

microbiome. This composition in turn matched fetal gut
microbiome rather than adult gut and skin. Firmicutes/
Proteobacteria ratio had a higher significance in determining DDD (p=0.064) compared to Actinobacteria/Proteobacteria (p=0.08) and Actinobacteria/Firmicutes ratio(p=0.08).
Conclusions: Our study has traced the origin of nucleus
pulposus microbiome to that of human fetal gut throughendplate and has also clearly established the role of gutskin-spine axis in maintaining tissue homeostasis. Further, we have identified Firmicutes/Proteobacteria ratio asa potential biomarker of DDD.

PS-FP-2-13

The Catastrophization Effects of a Magnetic
Resonance Imaging Report on the Patientand Surgeon and the Benefits of ‘Clinical
Reporting’Dilip Chand Raja Soundararajan1, S. Rajasekaran1,
B. T. Pushpa Bhari2, Anand Kumar Behera1,
Shetty Ajoy Prasad1, Kanna Rishi Mugesh1
1

Department of Spine Surgery, Ganga Hospital, Coimbatore, India
Department of Radiology, Ganga Hospital, Coimbatore, India

2

Purpose: Inappropriate use of magnetic resonance imaging (MRI) leads to increasing interventions and surgeries
for low back pain (LBP). We probed the potential effects
of a routine MRI report on the patient’s perception of his
spine and the functional outcome of treatment. An alternate ‘clinical reporting’ was developed and tested for benefits on LBP perception.
Methods: In phase I, 44 LBP patients were randomized
to group A who had a factual explanation of their MRI
report or group B, who were reassured that the MRI findings showed normal changes. The outcome was comparedat 6 weeks by Visual Analog Scale, Pain Self-Efficacy
Questionnaire-2, and 12-item Short-Form Health Survey.
In phase II, clinical reporting was developed, avoiding
potential catastrophizing terminologies. In phase III, 20
MRIs were reported by both routine and clinical methods.
The effects of the two methods were tested on four categories of health care professionals (HCP) who read themblinded on their assessment of severity of disease, possible
treatment required, and the probability of surgery.

Results: Both groups were comparable initial by demographics and pain. After 6 weeks of treatment, group A
had a more negative perception of their spinal condition,
increased catastrophization, decreased pain improvement,
and poorer functional status (p=significant for all). The
alternate method of clinical reporting had significant benefits in assessment of lesser severity of the disease, shift tolesser severity of intervention and surgery in three groupsof HCPs.
Conclusions: Routine MRI reports produce a negative
perception and poor functional outcomes in LBP. Focusedclinical reporting had significant benefits, which calls forthe need for ‘clinical reporting’ rather than ‘image reporting’.

PS-FP-2-14

Sub-Clinical Infection Can Be an Initiatorof Inflammaging Leading to Degenerative
Disc Disease: Evidence from Host Defense
Response Mechanisms
Dilip Chand Raja Soundararajan1,
Sharon Miracle Nayagam2, Sri Vijayanand KS1,
Tangavel Chitraa2, Muthurajan Raveendran3,
Shetty Ajoy Prasaad1, Kanna Rishi Mugesh1, S Rajasekaran1
1

Department of Spine Surgery, Ganga Hospital, Coimbatore, India
Department of Proteomics, Ganga Research Centre, Coimbatore, India
3
Department of Plant Biotechnology, Tamilnadu Agricultural University,
Coimbatore, India
2

Purpose: There is considerable controversy on the role ofgenetics, mechanical and environmental factors, and, recently, on sub-clinical infection in triggering inflammaging leading to disc degeneration. The present study investigated sequential molecular events in the host, analyzingproteome level changes that will reveal triggering factorsof inflammaging and degeneration.
Methods: Ten magnetic resonance imaging normal discs(ND) from braindead organ donors and 17 degenerated
discs (DD) from surgery were subjected to in-gel basedlabel-free ESI-LC-MS/MS (electrospray ionization-liquid
chromatography tandem mass spectrometry) analysis.
Bacterial-responsive host-defense response proteins/pathways leading to inflammaging were identified and compared between ND and DD.
Results: Out of the 263 well-established host defense

Asian Spine Journal
response proteins (HDRPs), 243 proteins were identified, and 64 abundantly expressed HDRPs were analyzed
further. Amongst the 21 HDRPs common to both ND
and DD, complement-factor-3 and heparan-sulphate-proteoglycan-2 were significantly upregulated, and lysozyme,
superoxide-dismutase-3, phospholipase-A2, and tissueinhibitor-of metalloproteinases-3 were downregulated in
DD. Forty-two specific HDRPs mainly, complement proteins, apolipoproteins, and antimicrobial proteins involvedin the complement cascade, neutrophil degranulation,and oxidative-stress regulation pathways representing an
ongoing host response to sub-clinical infection and uncontrolled inflammation were identified in DD. ProteinProtein interaction analysis revealed crosstalk between
most of the expressed HDRPs, adding evidence to bacterial presence and stimulation of these defense pathways.
Conclusions: The predominance of HDRPs involved incomplement cascades, neutrophil degranulation, and oxidative-stress regulation indicated an ongoing infectionmediated inflammatory process in DD. Our study has
documented increasing evidence for bacteria’s role intriggering the innate immune system leading to chronic
inflammation and degenerative disc disease.

PS-FP-2-15

Dynamic Ultrasound Imaging of Lumbar
Multifidus for Assessment of Lumbar Spinal
Muscles
Yongsoo Choi, Jihoon Park, Sangmin Lee, Seungwoo Shim
Department of Orthopaedics, Kwangju Christian Hospital, Gwangju, Korea

Purpose: It is important for the elderly to maintain sagittalbalance with constant exercise to keep good spinal rangeof motion and strength of back extensor muscle. Dynamic
ultrasound imaging is a potentially useful tool for the assessment of spinal muscles. This study was to investigate afeasibility of dynamic ultrasound imaging in lumbar multifidus muscle for assessment of lumbar spinal muscles.
Methods: This study was conducted on 23 volunteers
without history of spinal disease. The volume and thickness of lumbar multifidus muscle as a trunk stabilizer andrectus femoris muscle as a thigh stabilizer were measured
with dynamic ultrasound imaging, at rest and after exercise of the extensor muscle for strength of the extensor

S27

muscle. Compared to individuals of sarcopenia diagnostic
criteria such as gait speed, hand grip strength, and changes in muscles volume and thickness at the state of rest andafter the exercise had been analyzed.
Results: At rest, the mean volume and thickness oflumbar multifidus muscle were 357.17±59.25 mm² and2.54±0.32 cm, respectively. After exercise, the mean volume and thickness of lumbar multifidus muscle varied to407.35±70.10 mm² and 2.78±0.36 cm, respectively. Therewas significant increment of lumbar multifidus muscle
volume (14.00%, p=0.01) and thickness (9.42%, p=0.01).
At rest, the mean volume and thickness of rectus femorismuscle were 129.50±36.26 mm² and 1.19±0.10 cm, respectively. After exercise, the mean rectus femoris muscle volume and depth varied to 157.58±42.40 mm² and 1.40±0.12cm, respectively. There was significant increment of rectus
femoris muscle volume (21.94%, p=0.01) and thickness(17.63%, p=0.01). The mean of gait speed was 9.80±1.72
seconds and the mean hand grip strength was 19.30±2.08
kg. There was positive correlation between changes oflumbar multifidus volume and hand grip strength (r=0.56,
p=0.01) and negative correlation between changes of rectus
femoris volume and gait speed (r=-0.87, p=0.01)
Conclusions: These results suggest that dynamic ultrasound imaging of the multifidus muscles could be used to
document improvements over time and with intervention
as a visual feedback to enhance therapeutic effect for lumbar spinal muscle.

PS-FP-2-16

Examination of Surgical Procedure forLower Lumbar Osteoporotic Vertebral Body
Fractures
Yuji Kasukawa, Naohisa Miyakoshi, Michio Hongo,
Yoshinori Ishikawa, Daisuke Kudo, Yoichi Shimada
Department of Orthopedic Surgery, Akita University Graduate School of
Medicine, Akita, Japan

Purpose: Osteoporotic vertebral fractures (OVF) in thelower lumbar spine (L3, 4, 5) may cause radiculopathy due
to foraminal stenosis by the fracture. Furthermore, since thefracture causes lumbar kyphosis, the total spinal alignment
may be deteriorated, and the activities of daily living and thequality of life are also deteriorated. Therefore, it is necessary

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Asian Spine J 2021;15(Supplement 1):S1-S177

to determine the surgical procedure according to the symptom. The purpose of this study is to investigate the surgicalprocedure for OVF in the lower lumbar spine and the number and range of fixation levels in the fusion surgery.
Methods: Two-hundred and sixty-eight patients (50males, 218 females; average age, 76 years) who underwent
surgery for OVF during the 10 years from 2009 to 2018
in the Akita Spine Group were evaluated. The number ofoperations for OVF in the lower lumbar spine, surgicalprocedure, ratio of fusion surgery, number of fixation levels, and fixation range for OVF in the lower lumbar spine
were examined.
Results: The number of surgeries for OVF in the lower
lumbar spine was 52 (19%; 8 males, 44 females; average age, 77 years). As for the surgical method, posterior
lumbar interbody fusion was the most common in 26
cases, posterior decompression fusion (PSF) in six cases,
posterior vertebroplasty+PSF in four cases, lateral vertebral replacement+PSF in two cases, lateral interbody
fixation+PSF in one case, decompression only in four cases, and percutaneous vertebroplasty in nine cases (L3: fivecases, L4: three cases, L5: one case). Fusion surgery was
performed in 39 cases (75%), and the number of fusionlevels were one in six cases, two in 11 cases, three in threecases, four in seven cases, and five or more in 12 cases.
Upper instrumented vertebra was middle or lower thoracic vertebrae (T8–12) in 11 cases, L1 in four cases, L2
in nine cases, L3 in 11 cases, and L4 in four cases. Lower
instrumented vertebra was L3 in one case, L4 in six cases,
L5 in 18 cases, S1 in five cases, and pelvis in nine cases.
Conclusions: Surgery for OVF in the lower lumbar spine
accounted for 19% of surgery for OVFs. Of these, 75%
had fusion surgery, but the range of fixation varied fromsingle to multi-level fixation.

PS-FP-2-17

Clinical Relationship between Spinopelvic
Alignment and Lumbar Spinal Canal Stenosis
in Patients with Rheumatoid Arthritis
Shunsuke Ito, Yoichi Iizuka, Eiji Takasawa, Tokue Mieda,
Sho Isiwata, Yusuke Tomomatsu, Kazuhiro Inomata,Hideo Sakane, Koichi Okamura, Hirotaka Chikuda
Department of Orthopaedic Surgery, Gunma University Graduate School of
Medicine, Maebashi, Japan

Purpose: To elucidate the spinopelvic parameters associated with lumbar spinal canal stenosis (LSS) in rheumatoid
arthritis (RA) patients.
Overview of Literature: RA is a systemic inflammatory
disease that can cause joint destruction and deformity.
Cervical spine involvement of RA (e.g., atlantoaxial subluxation) is well documented, but the clinical relationshipbetween the spinopelvic alignment and lumbar spine involvement remains unclear.
Methods: A total of 73 outpatients with RA were enrolled.
Patients who underwent any spine surgery were excluded.
LSS was diagnosed in cases with clinical symptoms andlumbar magnetic resonance imaging findings (grade≥2 in the Lumbar Stenosis Index), and patients were divided into two groups: group S (with LSS) and group NS(without LSS). The spinopelvic parameters on wholespine standing radiography were analyzed, including thethoracic and lumbar Cobb angle, C7 sagittal vertical axis
(C7-SVA), thoracic kyphosis, pelvic tilt (PT), sacral slope,
pelvic incidence (PI), lumbar lordosis (LL), and PI–LL
mismatch.
Results: Seventeen of the 73 patients (23.3%) were diagnosed with LSS (S group), leaving 56 patients (76.7%) in
the NS group. In the univariate analysis, there were no
significant differences in the age or sex between the twogroups. However, patients in the S group showed a greater
value of PT (47.5 vs. 33.8, p=0.020), C7-SVA (48.0 vs. 33.7,
p=0.015), and PI–LL (49.2 vs. 33.3, p=0.007) than those in
the NS group. A logistic regression analysis showed that
the PT (odds ratio [OR], 1.098; p=0.015) and C7-SVA (OR,1.017; p=0.021) were factors independently associatedwith LSS in RA patients.
Conclusions: As with non-RA patients, sagittal spinopelvic parameters, such as the PT and C7-SVA, were clinically important in RA patients with LSS.

Asian Spine Journal
PS-FP-2-18

Lumbar Disc Degeneration and Vertebral
Fracture at Thoracolumbar Junction Are
Risk Factors for Chronic Low Back Pain with
Disability: The Wakayama Spine Study
Hiroshi Hashizume1, Masatoshi Teraguchi2,
Hiroyuki Oka3, Yuyu Ishomoto1, Keiji Nagata1,
Ryohei Kagotani1, Hiroki Iwahashi1, Motohiro Okada4,
Masanari Takami1, Shunji Tsutsui1, Hiroshi Iwasaki1,
Akihito Minamide1, Yasutsugu Yukawa1,
Munehito Yoshida4, Noriko Yoshimura3, Hiroshi Yamada1
1

Department of Orthopaedic Surgery, Wakayama Medical University,
Wakayama, Japan2
Department of Orthopaedic Surgery, Wakayama Medical University
Kihoku Hospital, Katsuragi, Japan
3
22nd Century Medical and Research Center, The University of Tokyo
Hospital, Tokyo, Japan
4
Sumiya Orthopedic Hospital, Wakayama, Wakayama, Japan

Purpose: To elucidate the risk factors of chronic low backpain (CLBP) among degenerative changes on magnetic
resonance imaging (MRI) in a general population.
Overview of Literature: It is still controversial about therelationship between the degenerative changes on MRI
and CLBP. Disc degeneration (DD), vertebral deformity
due to osteoporotic fracture, and spinal stenosis have beenreported as possible causes of CLBP. However, these degenerative changes are often coexisting and may confoundeach other as the cause of CLBP.
Methods: This is a longitudinal study using an establishedpopulation-based cohort in Japan. A total of 1,009 subjects
who participated in the baseline survey of the Wakayama
Spine Study (AD 2008-9) were subjected to the MRI
evaluation. Lumbar DD (Phirrmann’s classification: grade
1–5), and morphometric fracture of the vertebral bodies(semi-quantitative method: SQ grade 0–3) were evaluatedon the sagittal MRI. Lumbar spinal stenosis (Suri’s classification: grade 0–3) was evaluated on the axial MRI. In
the third survey of the Wakayama Spine Study (AD 20156), we followed-up 663 subjects (men 219, women 444;
age at the baseline, 62±13 years) and got the informationon the presence of CLBP (continued more than 3 month)and Oswestry Disability Index (ODI). The relationshipbetween the degenerative changes at the baseline and thepresence of chronic LBP with disability (ODI% ≥21) after
7 years was determined using multiple logistic regression
analysis including mental component summary scale ofS29

the 8-item Short Form Health Survey, smoking habit, age,sex, and body mass index (BMI) as the explanatory variables.
Results: The prevalence of disabled CLBP was 91/663(13.7%). Significant risk factors at baseline for the disabled
CLBP after 7 years were age (+1 year: odds ratio [OR], 1.07;
95% confidence interval [CI], 1.03–1.10), sex (female: OR,
3.69; 95% CI, 1.83–7.44), BMI (+1 kg/m2: OR, 1.11; 95%
CI, 1.02–1.20), sum of the lumbar disc degeneration grade(L1/2–L5/S, +1 point: OR, 1.14; 95% CI, 1.01–1.30), andsum of the SQ grade at the thoraco-lumbar junction (T11–
L1, +1 point: OR, 1.32; 95% CI, 1.10–1.60).
Conclusions: Lumbar DD and vertebral fracture at thoracolumbar junction were risk factors for CLBP with disability in the general population. Other factors that may
cause CLBP have been reported in addition to our evaluated items. The lack of them is the limitation of this study.
However, we consider the results of this study extremely
important both epidemiologically and clinically, because
there are few longitudinal studies on spinal degeneration
and related disability.

PS-FP-2-20

Advanced Glycation End Products Are
Associated with the Intensity of Back Pain
Symptoms in Patients with Lumbar Spinal
Stenosis
Masatoshi Teraguchi1, Mamoru Kawakami2,
Masafumi Nakagawa1, Yoshikazu Minetama1,
Sachika Matsuo1, Yoshio Yamamto1, Yoshio Enyo1,
Yukihiro Nakagawa1
1

Department of Orthopaedic Surgery Spine Care Center, Wakayama
Medical University Kihoku Hospital, Wakayama, Japan2
Department of Orthopaedic Surgery, Saiseikai Wakayama Hospital,
Wakayama, Japan

Purpose: Advanced glycation end products (AGEs) affectcells and trigger the generation of free radicals and expression of inflammatory gene mediators and are thought
to be one factor in aging. We clarified the association of
decreasing muscle mass in men and increasing fat massin women with increasing AGEs. However, there has
been no report of skin autofluorescence (AF) in patientswith low back pain. Skin AF associated with the content
of AGEs, such as pentosidine in skin biopsies, has been

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Asian Spine J 2021;15(Supplement 1):S1-S177

reported as a non-invasive method of measuring AGE
deposition by emission of a characteristic fluorescence. In
the present study, we measured the relationship between
AGEs and intensity of low back pain, lower limb pain, andnumbness in patients with lumbar spinal canal stenosis(LSS) for clarifying the degeneration to muscle or nerve
system.
Methods: Among the 160 LSS patients that were treated at
our center from September 2017 to May 2019, 44 patientswere excluded due to diabetes because diabetes were reported to be associated with AGEs. A total of 116 people
were included in this study. LSS was diagnosed by spinal
surgeons through examination and magnetic resonanceimaging. AF was measured by placing the device RQAG01J (Sharp Life Science Corp., Tenri, Japan) for 30
seconds with the AGEs. Intensity of low back pain, lower
limb pain and numbness were measured quantitatively by
Numerical Rating Scale (NRS), and the relationship withAF value was analyzed by Spearman’s rank correlation coefficient. Significance level was 5% or less.
Results: The subjects were 46 men (average age, 73.9
years) and 70 women (73.6 years). The average AF was
0.51±0.12 and the average NRS was 4.6±2.7 for low backpain, 5.1±2.8 for lower limb pain, and 4.2±3.0 for lower
limb numbness. The correlation coefficient between AF
and NRS was low back pain and ρ=0.20 (p<0.05), on theother hand, lower limb pain and ρ=0.15 (p=0.14), lower
limb numbness and ρ=0.07 (p=0.5).
Conclusions: AGEs that accumulate in the body withaging and RAGE which is a receptor for the AGEs, maycause degeneration to muscle or nerve systems. However,in this study, accumulation of AGEs and low back pain
were significantly associated with LSS patients, but no significant association with lower limb symptoms was found.
Therefore, the accumulation of AGEs may cause degeneration of muscle rather than neurodegeneration.

PS-FP-2-21

Patient-Reported Outcome of Lower Extremity
Improved after Posterior Decompression andLumbar Interbody Fusion for Degenerative
Lumbar Diseases
Sung-Min Kim1, Yong-Chan Kim1, Keun-Ho Lee2,
Ki-Tack Kim1, Kee-Yong Ha1, Joonghyun Ahn1, Qiang Luo1,
Seungnam Ko1, Kyeonguk Min1
1

Department of Orthopaedic Surgery, Kyung Hee University Hospital at
Gangdong, Seoul, Korea
2
Department of Orthopedic Surgery, Kangdong Sacred Heart Hospital,
Hallym University College of Medicine, Seoul, Korea

Purpose: There were no reports to evaluate the lower extremity functional outcome with lower extremity patientreported outcome measures (PROMs) after lumbar spine
surgery. Thus, the purpose of this study is to elucidate thechange of hip and knee PROMs after lumbar interbody fusion and to evaluate the spinopelvic sagittal radiographic
parameter most correlated with lower extremity PROMs.
Methods: In 2018, the patients who underwent lumbar interbody fusion surgery with three levels or less were consecutively evaluated. Pre- and postoperative 1-year clinicaland radiographic data were assessed. Functional outcomeof the spine was measured by the PROMs including Oswestry Disability Index, Visual Analog Scale for pain,
Scoliosis Research Society form, and that of lower extremity by Harris Hip Score (HHS) and Western Ontario andMcMaster Universities Osteoarthritis Index (WOMAC).
The linear regression was used to evaluate the relationshipof the spine and lower extremity PROMs with spinopelvic
radiographic parameters.
Results: A total of 67 patients (mean age, 66.4 years) wereenrolled. The average number of fused vertebrae was 1.7.
Spinopelvic parameters including lumbar lordosis (LL),pelvic tilt (PT), C7 sagittal vertical axis, and sagittal radiograph of hip and knee were significantly improved after
surgery. All the PROMs we have checked improved significantly after the surgery including HHS and WOMAC(HHS, p=0.042; WOMAC, p=0.033). With linear regression test, HHS and WOMAC correlated with LL and PT,
respectively (HHS with LL, β=0.554, p=0.043; WOMAC
with PT, β=1.573, p=0.021)
Conclusions: The current study demonstrated that posterior decompression and lumbar interbody fusion surgery
could expect postoperative improvement of lower extrem-

Asian Spine Journal
ity functional outcome as well as radiographic improvement of spine and lower extremities. Among radiographic
parameters, however, LL and PT should be noted as
whose changes were most associated with the lower extremity PROMs.

PS-FP-2-22

Prevalence and Characteristics of Osteoporotic
Vertebral Fracture in Elderly Patients with
Sagittal Imbalance
Akito Yabu1, Masatoshi Hoshino1, Yusuke Hori1,
Shinji Takahashi1, Shoichiro Ohyama1, Akinobu Suzuki1,
Tadao Tsujio2, Hidetomi Terai1, Sho Dohzono3,
Ryuichi Sasaoka3, Hiromitsu Toyoda1, Minori Kato4,
Akira Matsumura4, Takashi Namikawa4, Masahiko Seki2,
Hiroaki Nakamura1
1

Department of Orthopaedic Surgery, Osaka City University Graduate
School of Medicine, Osaka, Japan2
Department of Orthopaedic Surgery, Shiraniwa Hospital, Ikoma, Japan3
Department of Orthopaedic Surgery, Yodogawa Christian Hospital, Osaka,Japan
4
Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka,Japan

Purpose: Osteoporotic vertebral fracture (OVF) is a widely known cause of sagittal imbalance in elderly people, but
its prevalence and characteristics remain unclear. The aimof this study was to determine the prevalence and characteristics of OVF in elderly patients with sagittal imbalance.
Methods: This study enrolled 1,962 patients who underwent whole-spine radiography at our hospital or related
institutions. We included patients aged ≥65 years who had
no history of spinal fusion or hip/knee surgery and nohistory of Parkinson’s disease. We evaluated the Genantclassification of OVF and calculated the spinal deformity
index (SDI) for each lesion (thoracic, thoracolumbar, andlower lumbar) by summing the grade of each vertebra.
The Visual Analog Scale (VAS) score for low back pain,
Oswestry Disability Index (ODI), and EuroQol fivedimension (EQ5D) were used in the clinical evaluation.
First, the patients were divided into the following groups:
sagittal vertebral axis (SVA) <40 mm (SVA40 group), 40mm≤ SVA <95 mm (SVA40–95 group), and 95 mm≤ SVA(SVA95 group). The prevalence of OVF in each group wasinvestigated. Next, multivariate ordinal logistic regression
analysis was performed to analyze the relationship be-

S31

tween the severity of SVA and OVF. Finally, clinical scores
were compared with or without OVF in each group.
Results: A total of 965 patients (mean age, 74.4 years; 483
women) were included. The prevalence of OVF (Genantclass ≥2) was 11.4% in the SVA40 group, 19.1% in the
SVA40–95 group, and 37.7% in the SVA95 group. Age(odds ratio [OR], 1.86), female sex (OR, 1.56), and SDI at
the thoracolumbar spine (OR, 1.23) significantly affected
the severity of SVA (p<0.01). In the SVA40 group, the VAS
score for low back pain (41.8 vs. 26.7), ODI (26.3 vs. 17.5),
and EQ5D (0.73 vs. 0.82) were significantly poor in patients with OVF (p<0.01), but the differences in all clinicalscores with or without OVF were not significant in the
SVA95 group.
Conclusions: The prevalence of OVF in elderly patientswith severe kyphosis was 37.7%. It was significantly higher
than that in the other groups. SDI of the thoracolumbar
lesion affected sagittal imbalance. Furthermore, no significant difference in clinical scores was found in patientswith severe spinal malalignment due to the presence of
OVF. On the other hand, the presence of OVF affected theback pain and quality of life of patients with mild sagittal
imbalance.

PS-FP-2-26

Effect of Segmental Lordosis on Early-Onset
Adjacent Segment Disease after Posterior
Lumbar Interbody Fusion
Shinya Okuda1, Yukitaka Nagamoto1, Shota Takenaka2,
Masato Ikuta1, Tomiya Matsumoto1, Yoshifumi Takahashi1,
Masayuki Furuya1, Motoki Iwasaki1
1

Department of Orthopaedic Surgery, Osaka Rosai Hospital, Sakai, Japan
Department of Orthopaedic Surgery, Osaka University Medical School,
Suita, Japan
2

Purpose: Although several reports have described adjacentsegment disease (ASD) after posterior lumbar interbody
fusion (PLIF), there have been only few reports focusing on early-onset ASD. The purpose of this study was toinvestigate the prevalence, the postoperative pathologies,
and the relation with the radiological parameters such as
segmental lordosis (SL) of early-onset ASD.
Methods: A total of 256 patients, who underwent single
segment PLIF at L4/5 for degenerative lumbar spondy-

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Asian Spine J 2021;15(Supplement 1):S1-S177

lolisthesis (DS) and were followed up for at least 5 years,
were reviewed. The definition of ASD was symptomaticcondition requiring additional operation at the adjacent fusion segment. ASD occurring within 3 years after
primary PLIF was categorized as early-onset ASD. As
a control group, 54 age- and sex-matched patients who
have not suffered from ASD for more than 10 years wereselected from this series. The following were investigated:(1) prevalence of ASD at postoperative 3, 5, 10 years andthe final follow-up period; (2) postoperative pathologies
of early-onset ASD; (3) comparison of the radiologicalresults between the ASD and control groups; and (4) the
relation between radiological parameters and early-onset
ASD.
Results: There were 42 patients with ASD at the final
follow-up. ASD prevalence at postoperative 3, 5, 10 years
and the final follow-up period were 5.0%, 8.2%, 14.1%,
and 16.4%, respectively. With respect to ASD pathologies,
lumbar disc herniation (LDH) was significantly morecommon in early-onset ASD, while lumbar spinal canalstenosis and DS occurred more frequently in late-onset
ASD. Significant differences were detected in postoperative range of motion (ROM) and the change amount of
ROM at L3/4 (cranial adjacent fusion segment), and thechange amount of SL (ΔSL) at L4/5 (fused segment), while
there was no difference in other pre- and postoperative
parameters. Stepwise logistic regression analysis showedthat ΔSL was identified as an independent variable(p=0.008). ΔSL demonstrated significant difference, especially in early-onset ASD (control, 1.1°; overall ASD, -2.4°,
p=0.002; early-onset ASD, -6.6°, p=0.00004). According to
the statistical analysis, increasing ΔSL by 1° resulted in an
odds ratio of 0.854 at which ASD occur. The cut-off value
for ΔSL on the receiver operating characteristic curve to
identify ASD was -0.5° (sensitivity 67%, specificity 62%).
Conclusions: LDH was significantly more common as apathology in early-onset ASD. ΔSL was a major risk factor
for ASD, especially in early-onset ASD. Surgeons should
try not to reduce the SL compared to before surgery.

PS-FP-2-27

Facet Joint Opening on Computed Tomography
Is a Predictor for Poor Clinical Outcomes afterLess-Invasive Decompression Surgery for
Lumbar Spinal Stenosis
Kentaro Yamada1,2, Hiromitsu Toyoda2, Shinji Takahashi2,
Koji Tamai2, Akinobu Suzuki2, Masatoshi Hoshino2,
Hidetomi Terai2, Hiroaki Nakamura2
1

Department of Orthopaedic Surgery, Fuchu Hospital, Izumi, Japan
Department of Orthopaedic Surgery, Osaka City University, Osaka, Japan

2

Purpose: Postoperative instability after decompression
alone procedures for lumbar spinal stenosis (LSS) often
become problematic, especially in patients with segmental
instability at index lumbar level. It has not been clarified
what is the best useful parameter evaluating segmental instability in LSS. Facet joint opening was reported as an indicator for segmental spinal instability by an experimental
study. However, no study has investigated the impact of
facet joint opening on clinical outcomes after decompression alone surgery. The purpose of this study was to investigate impact facet joint opening on clinical outcomes
after less-invasive decompression surgery for LSS in a
retrospective longitudinal cohort study
Methods: This study included 296 patients who underwent less-invasive surgery for LSS and have followed up≥5 years in one institution. Facet opening was defined as awidth of >2.0 mm at the middle images of each facet joint
in the axial plane of preoperative computed tomography.
We focused on facet joint opening at index decompression
level (d-FJO) and ≥3 levels of facet joint opening within
lumbar segment (m-FJO). Clinical outcomes were investigated regarding reoperations, improvement ratio of Japanese Orhopaedic Association (JOA) score, and achievement of minimal clinically important difference (MCID)
of Visual Analog Scale (VAS) for low back pain (LBP) or
leg pain at 5 years. Clinical outcomes were compared between patients with and without d-FJO or m-FJO.
Results: The d-FJO were observed in 129 patients (44%);
more common in case with lateral olisthesis. The m-FJO
were observed in 62 patients (21%); less common in casewith spondylolisthesis. Reoperations were more common
in patients with d-FJO (15% vs. 5%). Cox proportional
hazard analysis indicated d-FJO were predictor for revision at index decompression level (hazard ratio [HR], 4.04;

Asian Spine Journal
p=0.03), and m-FJO for revision at other lumbar levels(HR, 3.71; p=0.03). Patients with m-FJO showed slightly
lower rate of achieving MCID of VAS for LBP (34% vs.
52%, p=0.03), and poorer improvement of JOA score (74%vs. 80%, p=0.03).
Conclusions: The facet joint openings, not only that atindex level but also multi-level facet joint opening, werepredictor for poor outcomes. Patients with facet joint
opening should be carefully selected surgical strategy, or
followed with special attention.

PS-FP-2-29

Osseous Union after Posterior Lumbar
Interbody Fusion: Pay Attention to Large
Interbody Angle
Keichi Nakai1, Tomohiko Hasegawa1, Yu Yamato2,
Go Yoshida1, Tomohiro Banno1, Hideyuki Arima1,
Shin Oe2, Yuki Mihara1, Hiroki Ushirozako1,
Tomohiro Yamada1, Koichiro Ide1, Yu Watanabe1,
Kenta Kurosu1, Hirotaka Haro3, Jun Takahashi4,
Keijiro Mukaiyama5, Yukihiro Matsuyama1
1

Department of Orthopedics, Hamamatsu University School of Medicine,
Hamamatsu, Japan
2
Division of Geriatric Musculoskeletal Health, Hamamatsu University Schoolof Medicine, Hamamatsu, Japan3
Department of Orthopedics, University of Yamanashi, Kofu, Japan
4
Department of Orthopedics, Shinshu University, Matsumoto, Japan
5
Department of Orthopedics, North Alps Medical Center Azumi Hospital,
Nagano, Japan

Purpose: Posterior lumbar interbody fusion (PLIF) has
been reported to have a high rate of osseous union, butthere are some cases of poor results due to lack of osseousunion. Poor contact between the vertebral endplate andthe grafted bone has been reported as a factor for failureof osseous union. In this study, we focused on the local intervertebral angle and the shape of the endplate as factorsthat may lead to poor contact between the endplate andthe grafted bone, and investigated the effects on interbody
osseous union after PLIF.
Methods: A total of 116 patients (63 males and 53 females; mean age, 67 years) who underwent single-level
PLIF at 11 institutions (Hamamatsu University School of
Medicine, University of Yamanashi, Shinshu University,and their affiliated hospitals) were included in the study.
The intervertebral angle (the angle between the inferior

S33

endplate of the upper vertebral body and the superior
endplate of the lower vertebral body), the depression of
the endplate (the distance between the line connecting theanterior and posterior endplates and the most depressedarea in the center of the endplate), the gap between theendplate and the cage (the three points of the cage, anterior, middle, and posterior) in the immediate postoperative computed tomography (CT). The intervertebral osseous union was measured by CT 1 year after surgery. The
results were divided into two groups: the union group (Ugroup) and the nonunion group (N group).
Results: Fifty-four patients (47%) showed osseous union(U group), while 62 patients (53%) did not (N group).
The mean preoperative intervertebral angle was 4.8° in U
group and 7.8° in N group (p<0.05). The mean preoperative intervertebral angle was 4.8° in U group and 7.8° in
N group (p<0.05). The depression of the endplate was 2.6
mm in U group and 2.8 mm in N group (p=0.48). The
anterior cage gap was 0.7 mm in U group and 1.5 mm
in N group (p<0.05), the middle was 0.7 mm and 1.4
mm (p<0.05), and the posterior was 0.4 mm and 0.4 mm(p=0.14). The intervertebral bone fusion rate between vertebrae with an intervertebral angle of 10° or less was 54%,
whereas the intervertebral bone fusion rate between vertebrae with an intervertebral angle greater than 10° was
19%.
Conclusions: The intervertebral osseous union rate wassignificantly lower in the intervertebral space with a larger
intervertebral angle.

PS-FP-2-30

Symptomatic Post-surgical Lumbar Pseodomeningocoele Treated by Ultrasound Guided
Blood Patch Application: A Case Report
Rohit Akshay Kavishwar, Ajoy Prasad Shetty,
S. Rajasekaran
Department of Spine Surgery, Ganga Medical Center, Coimbatore, India

Purpose: Post-surgical pseudomeningoceles are extradural collections of cerebrospinal fluid (CSF) that result
following an intraoperative dural breach. Though usuallyasymptomatic and self subsiding, they may present withsymptoms of postural headache, blurred vision, diplopia,
photophobia, back pain, radiculopathy, and vomiting.

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Asian Spine J 2021;15(Supplement 1):S1-S177

Most of the cases recover with conservative measures likebed rest, hydration, and pressure dressings. Symptomaticpatients usually require surgical re-exploration and direct
open repair of the durotomy. We report a case of 48-yearold female who presented with lumbar pseudomeningocoele following lumbar microdiscectomy. She was treatedwith pseodomeningocoele aspiration and application ofblood patch.
Methods: A 48-year-old lady presented at our hospitalwith a fluctuant, globular swelling on her back 1-month
post microdiscectomy for L4–L5 disc prolapse. She also
had back pain, left lower limb radiculopathy and postural
headache. She had no neurologic defect. Magnetic resonance imaging (MRI) showed left L4 laminectomy defectwith a pseudomeningocoele having an ill-defined CSF
intensity collection in posterior paraspinal region measuring 5.5×4.2×4 cm. We treated the case by ultrasound(USG)-guided CSF aspiration from the pseudomeningocele and application of epidural blood patch.
Results: We treated the case by USG-guided CSF aspiration from the pseudomeningocele and application of an
epidural blood patch. Under all aseptic precautions, L3–
L4 and L4–L5 spaces were identified, and CSF was aspirated from the pseudomeningocoele at L4–L5 space witha Tuohy needle. At the same time, 20 mL of blood was
drawn from the antecubital vein, followed by 10 mL blood
injection at L4–L5 and 10 mL at L3–L4 epidural space
under USG guidance. The patient was made to sit for 15
minutes. Her postural headache and lower limb radiculopathy were immediately relieved following the procedure. She was symptom-free 1 year post-surgery with full
resolution of pseuodomeningocoele on MRI.
Conclusions: Most of the post-surgical pseodomeningocoeles are asymptomatic and resolve either spontaneously
or with conservative methods. Various treatment options
like close observation for spontaneous resolution, conservative measures such as bed rest, lumbar subarachnoid
drainage, pressure dressings, hydration, use of an abdominal binder, have been recommended. Re-explorationand surgical repair of defect should be reserved for thosecases presenting clinically with the features of intracranial
hypotension, neurological worsening, external fistula, or
infection. In our case, we successfully treated a pseodomenigocoele by aspiration and blood patch application
one level above the pseodomeningocoele and also inside
the cavity.

PS-FP-2-31

Titanium Cages May Be Superior to Polyetheretherketone Cages in Lumbar Interbody
Fusion: A Systematic Review and MetaAnalysis of Clinical and Radiological Outcomes
Jun-Hao Tan, Chin Kai Cheong, Dennis Hey
National University Hospital, Singapore

Purpose: Interbody cages are commonly used to augmentinterbody fusion. Commonly used materials include titanium (Ti) and polyetheretherketone (PEEK), with theirinherent differences. The aim of this study is to perform asystematic review and meta-analysis to compare the various clinical and radiological outcomes of Ti and PEEK
interbody spinal cages.
Methods: A systematic review and meta-analysis comparing clinical and radiological outcomes between Ti and
PEEK interbody cages in patients undergoing spinal fusion was performed. PubMed, Scopus, Web of Science,
Embase, and Cochrane Central Register of Controlled
Trials database were searched. All studies that compared
the clinical and radiological outcomes of patients who
underwent Ti and PEEK cages were included. Subgroup
analyses were performed to differentiate between patients
who had a cervical and lumbar interbody fusion.
Results: A total of 11 articles were identified, with a totalof 743 patients. Spinal fusion rates at final follow-up did
not differ between Ti and PEEK cages (odds ratio [OR],1.50; 95% confidence interval [CI], 0.57–3.94; p=0.41),
although in patients undergoing lumbar fusion, Ti cages
demonstrated superior fusion (OR, 2.12; 95% CI, 1.05–
4.28; p=0.04). In patients with non-infective etiologies, Ti
cages had a higher rate of cage subsidence (relative risk,
2.17; 95% CI, 1.13–4.16; p=0.02). Both types of cages had
similar operating time, postoperative hematoma formation, neuropathic pain, segmental angle correction, andpostoperative clinical outcome improvement.
Conclusions: In non-infective lumbar spine conditions, Ti
cage may be the superior option due to the higher fusion
rate.

Asian Spine Journal
PS-FP-2-32

Risk Factors for Postoperative Ileus after
Oblique Lateral Interbody Fusion: A Multivariate
Analysis
Sung Cheol Park1, Sam Yeol Chang1, GeunWu Gimm1,
Hyoungmin Kim1, Sujung Mok1, Bong-Soon Chang1,
Choon-Ki Lee2
1

Department of Orthopaedic Surgery, Seoul National University Hospital,
Seoul, Korea
2
Chamjoeun Hospital, Gwangju, Korea

Purpose: Oblique lateral interbody fusion (OLIF) has
become a widely used, efficient surgical tool for various
degenerative lumbar conditions. Postoperative ileus (POI)
is a relatively common complication after anterior lumbarinterbody fusion due to the manipulation of the intestineduring the surgical approach. However, to our knowledge,
little is known about POI following OLIF even though
it also involves bowel manipulation during a surgicalprocedure. The aim of the present study is to assess theincidence of POI and identify independent risk factors for
POI development after OLIF.
Methods: A retrospective analysis was performed for all
consecutive patients who underwent OLIF from August2012 through October 2019 at a single institution. POI
was defined as two or more of the following criteria met
on or after the postoperative day 3: (1) nausea or vomiting, (2) the absence of flatus or stool, (3) inability to tolerate an oral diet over a 24-hour period, (4) abdominal
distention, and (5) radiologic confirmation. Patients with
POI were identified by review of hospital stay medical records. The subjects were divided into two groups: patientswith POI and those without POI. Binary logistic regression analyses were performed on demographic, comorbidities, and perioperative factors to identify independentrisk factors for POI.
Results: Eighteen (3.9%) of 460 patients experienced
POI after OLIF and percutaneous pedicle screw instrumentation. Patients with POI had a significantly longer
postoperative length of hospital stay than those without
POI (8.61±2.66 vs. 6.48±2.64, p=0.001). Multivariate logistic regression analysis identified inadvertent endplate
fracture (adjusted odds ratio [aOR], 6.017; p=0.001) andthe amount of intraoperative remifentanil (aOR, 1.057;
p=0.024) as independent risk factors for the occurrence of
POI following OLIF.

S35

Conclusions: This study identified inadvertent endplate
fracture and the amount of intraoperative remifentanil as
independent risk factors for the development of POI after
OLIF.

PS-FP-2-36

A Rare Case of Idiopathic Dorsal Spinal Cord
Herniation Perforating the Lamina
Kento Yamanouchi1, Haruki Funao1,2,3, Kenshi Daimon1,2,
Norihiro Isogai2,3, Yutaka Sasao2,3, Shigeto Ebata1,2,
Ken Ishii1,2,3
1

Department of Orthopaedic Surgery, International University of Health andWelfare (IUHW) Narita Hospital, Narita, Japan2
Department of Orthopaedic Surgery, School of Medicine, International
University of Health and Welfare (IUHW), Otawara, Japan3
Department of Orthopaedic Surgery, International University of Health andWelfare (IUHW) Mita Hospital, Tokyo, Japan

Purpose: Spinal cord herniation (SCH) is a rare condition
associated with tethering of the spinal cord at the ventral
dural defect. Idiopathic dorsal SCH (IDSCH) is an extremely rare disease condition. To our knowledge, there
are no reports of IDSCH perforating the lamina. Here, we
describe a rare case of IDSCH perforating the lamina in a
74-year-old female patient with a history of ossification of
the ligamentum flavum (OLF) and diffuse idiopathic skeletal hyperostosis (DISH).
Methods: A 74-year-old female presented with difficultyin ambulation. The patient felt a sense of discomfort withher right lower extremity 5 years ago, and she noticed
numbness and weakness 6 months prior to presentation.
On her neurological examination, the patient showed motor weakness in the right lower extremity. Decreased sensation and impaired proprioception were observed in theright lower extremity. She also had urological symptoms.
Her magnetic resonance images demonstrated that the
spinal cord deviated from the midline and migrated into
the right L1 lamina. Her computed tomography myelogram demonstrated OLF at the thoracolumbar spine.
Results: Because her symptoms progressively deteriorated,a surgical treatment was performed. A laminectomy ofTh12 and L1 was performed, followed by the untetheringof the spinal cord. Because there was severe adhesion between the ossified dura and lamina, diffuse dural ossification was removed entirely. Although her motor weakness

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Asian Spine J 2021;15(Supplement 1):S1-S177

worsened immediate after surgery, it had recovered andmarkedly improved at 3 months after surgery compared
to preoperative findings. Urological symptoms did not
improve, and impaired proprioception in the right lower
extremity remained during her follow-up.
Conclusions: Here, we reported a rare case of IDSCH perforating the lamina in a patient who had a history of OLF
and DISH. Untethering of the spinal cord was performedby removing the surrounded ossified dura. Although urological symptoms and impaired proprioception remained,motor weakness markedly improved, and progressive
neurological deterioration was prevented after surgery. Because this disease condition is extremely rare, it should be
differentiated from other spinal disorders and ventral SCH.

PS-FP-2-37

Discogenic Low Back Pain Can Be Diagnosed
with an Ultrasonographic-Guided Disc Pain
Induction Test
Keisuke Masuda1, Manabu Maeda2, Hideki Shigematsu3,
Akinori Okuda4, Sachiko Kawasaki3, Yuma Suga3,
Yusuke Yamamoto3, Yasuhito Tanaka3
1

Department of Orthopaedics, Higashiosaka City Medical Center,
Higashiosaka, Japan2
Department of Orthopaedics, Maeda Orthopaedics Clinic, Nara, Japan3
Department of Orthopaedics, Nara Medical University, Nara, Japan
4
Department of Emergency and Critical Care Medicine, Nara Medical
University, Nara, Japan

Purpose: Diagnosis of discogenic pain includes physicalfindings and magnetic resonance imaging (MRI) findings.
However, when there are degenerations in multiple discs,
it is difficult to identify the responsible segment. The
ultrasonographic-guided disc pain induction test that wehave developed manually applies compression to the discwhile confirming the level of the disc using ultrasonography from the ventral side. We can easily and accurately
detect the responsible segment of discogenic pain by using this method. The purpose of this study is to examine
the usefulness of the ultrasonographic-guided disc pain
induction test in the diagnosis of discogenic pain.
Methods: The subjects were 27 cases (mean age, 45 years)
who visited an orthopedic outpatient clinic with a chiefcomplaint of low back pain. All of them had inducted painin the ultrasonographic-guided disc pain induction test.

Disc tenderness from L1/2 to L5/S was confirmed and
MRI was performed in all cases. In addition, disc injection using local analgesic was performed on the applicant,and the Visual Analog Scale (VAS) before and after the
injection was measured. The relationship between the tender level of disc and MRI findings was examined, and theeffect of disc injection was evaluated by using VAS before
and after the injection.
Results: A total of 40 discs had inducted pain. Seventeen
cases had tenderness at one disc, seven cases had tenderness at two discs, and three cases had tenderness at three
discs. Among the 27 discs with the strongest tenderness,
all cases had disc degeneration of Pfirrmann classification
grade 2 or higher. Regarding the Modic type, of the 27 intervertebral discs, two intervertebral discs were type 1, fourintervertebral discs were type 2, one intervertebral disc wastype 4, and the rest were type 0. The herniated disc wasfound in 11 cases, and the high-intensity zone of MRI wasfound in eight cases. Disc injection was performed in 15
patients, and the pre-injection mean VAS was 9.6 and thepost-injection mean VAS was 2.3. There was a significant
improvement in pain after the disc injection.
Conclusions: In the ultrasonographic-guided disc pain
induction test, there is a high association between the discof strongest tenderness and disc degeneration. Moreover,it was found that the responsible segment can be identified even when multiple disc degenerations are observed.
In conclusion, the ultrasonographic-guided disc pain induction test for discogenic pain can diagnose disc degeneration and identify the responsible segments.

PS-FP-2-38

Degenerative Lumbar Spondylolisthesis
Patients with Movement-Related Low Back
Pain Have Less Postoperative Satisfaction after
Decompression Alone
Ryosuke Hirota1, Mitsunori Yoshimoto1,
Naohisa Miyakoshi2, Yoichi Shimada2,
Toshihiko Yamashita1
1Department of Orthopaedic Surgery, Sapporo Medical University School of
Medicine, Sapporo, Japan2
Department of Orthopaedic Surgery, Akita University Graduate School of
Medicine, Akita, Japan

Purpose: Surgery for degenerative lumbar spondylolisthe-Asian Spine Journalsis (DLS) includes decompression alone and a decompression–fixation technique, both of which can yield poor
performance. We investigated if preoperative factors could
affect postoperative satisfaction after posterior lumbarinterbody fusion (PLIF) and microendoscopic musclepreserving interlaminar decompression (ME-MILD) in
DLS patients.
Methods: In this retrospective analysis of prospectively
collected multicenter observational data, we included 72
patients who underwent surgery for single-level mild DLS(PLIF: 79 patients; ME-MILD: 37 patients); however, 44
patients (PLIF: 31; ME-MILD: 13) were lost to follow-up.
Postoperative satisfaction was considered poor when the
Zurich claudication questionnaire satisfaction subscalescore exceeded 2 points. Clinical characteristics were investigated. Preoperative health-related quality of life questionnaires, such as the Japanese Orthopaedic Associationback pain evaluation questionnaire (JOABPEQ), Short
Form-36 Health Survey (SF-36) questionnaire, and Visual
Analog Scale (VAS), were compared between satisfied andnon-satisfied groups.
Results: No endogenous factors affected postoperative satisfaction in the PLIF group. In the ME-MILD cohort, thegroups differed significantly in terms of preoperative lumbar spine dysfunction items of the JOABPEQ (p<0.001),
and the role physical (p=0.04), and role emotional (p=0.03)
of the SF-36. Preoperative lumbar spine dysfunction andpostoperative satisfaction correlated strongly (r=0.59).
Conclusions: Preoperative lumbar spine function correlated with postoperative satisfaction in the ME-MILD
group. In cases with presurgical decreased lumbar spinefunction, the effect of decompression alone for DLS may
be limited. The surgical method should be selected considering the degree of low back pain upon movement.

S37

PS-FP-2-39

Extraforaminal Stenosis at L2–L3 Treated with
Microendoscopic Surgery: Report of Two
Cases
Arihiko Tsukamoto, Mitsunori Yoshimoto,
Akimitsu Oyama, Hisashi Obara, Ryunosuke Fukushi,
Kouta Kurihara, Ryousuke Hirota, Izaya Ogon,
Noriyuki Iesato, Toshihiko Yamashita
Sapporo Medical University, Sapporo, Japan

Purpose: The many cases of far-out syndrome that havebeen reported have involved extraforaminal stenosis at
L5–S1. We report two cases of extremely rare extraforaminal stenosis at L2–L3.
Case 1: A 59-year-old man presented with a half-year history of right leg pain. Radiological examination revealed
stenosis of the right L2 spinal nerve between the osteophyte of the vertebral body and the L3 right transverse
process. The right L2 spinal nerve was decompressed withmicroendoscopic surgery. Postoperatively, the pain in theright lower extremity was relieved.
Case 2: An 80-year-old man presented with a half-year
history of right leg pain. He had undergone posterior
lumbar fusion (L4–L5 and L5–S1) approximately 30 years
earlier. Radiological examination revealed stenosis of theright L2 spinal nerve between the osteophyte of the vertebral body and the L3 right transverse process. The rightL2 spinal nerve was decompressed with microendoscopic
surgery. Postoperatively, the patient had no symptoms andhis course over the next 6 months was good.
Conclusions: In both cases, we performed microendoscopic decompression of the L2 spinal nerve with good
postoperative results.

PS-FP-2-40

Giant Thoracic Disc Herniation Surgery
Isao Kitahara
Department of Neurosurgery, Hokusou Shiroi Hospital, Shiroi, Japan

Purpose: For thoracic disc herniation, we report thoracotomy, the main point of the giant thoracic disc herniation surgery by the transthoracic cavity method including

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Asian Spine J 2021;15(Supplement 1):S1-S177

monitoring and navigation.
Case 1: A 47-year-old man presented with a chest senseof incongruity and gait disturbance. A neurologic finding:
Tenioid sensory disturbance is detected in the T4–6. It
showed sensory disturbance of the part more plantar thanthe left waist than lower limbs, the right lumbar part. Imaging: The mass lesion of the diameter 2-cm size with thecalcification is remarkable in TH5/6. The surgery strategy
is as follows: (1) a preoperative day marking, navigation,
MEP, SEP; (2) using air mat, it is left lateral decubitus position; (3) an isolation lung awakening, the right thoracotomy, the right fifth intercostal space anterior thoracotomy,
6th rib rear resection; (4) it rises in the ventral aspect ofthe patients, and hernia is eliminated; and (5) after thehernial extraction, it is a closed chest.
Surgery: The practiced hand takes the ventral aspect ofthe patients with isolation lung ventilation, left lateral. Do
skin incision in the fifth intercostal space anterior, and cut
the fifth intercostal muscle open. After having separated
the ligament around the costotransverse joint which weseparated the 6th rib in a site of 1/3 rear, we cut a costotransverse ligament open. We cut pleura open at the costal
head and separated an abrasion, joint of the head of therib with costal periosteum and resected the 6th rib rear
sequentially. Resected bones toward the body of vertebra
than T5/6 foramen transthoracically and, using navigation, identified dura mater. Confirm that do not have liquorrhea, a closed chest. There are not postoperative newneurologic symptoms and becomes Japanese Orthopaedic
Association score 10 just after an operation.
Conclusions: We classify a surgical method for the thoracic disc herniation roughly, and there is the 2 methodsof a previous method and the latter method. There is little
exclusion about the spinal cord, and the front approach
method is an excellent surgical method. Because the effective head of surgery machinery and tools gets longer
including drill, the simulation of enough machinery andtools is necessary. We reported the main point of the thoracotomy front surgical therapy for the thoracic disc herniation.

PS-FP-2-42

Occurrence Rate of Sacroiliac Joint Disorders
before and after Lumbar Surgeries andTreatment Strategies
Daisuke Kurosawa1, Eiichi Murakami1, Hiroshi Ozawa2
1

Department of Orthopaedic Surgery, Low Back Pain and Sacroiliac Joint
Center, JCHO Sendai Hospital, Sendai, Japan2
Department of Orthopaedic Surgery, Tohoku Medical and Pharmaceutical
University School of Medicine, Sendai, Japan

Purpose: A scoring system to differentiate sacroiliac joint(SIJ) disorders (SIJDs) from lumbar spine diseases (lumbar
disc herniation [LDH] and lumbar spinal stenosis [LSS])
has been developed with a sensitivity of 90.3% and specificity of 86.4% for a total score of 4 or greater. High scores
before lumbar spine surgery are suspected to be combinedwith SIJDs, and high scores after lumbar surgery are suspected to be associated with new-onset SIJDs. The occurrence rates in patients with high SIJ scores before and after
lumbar surgery and treatment strategies were investigated.
Methods: One hundred and twenty-four patients (76 men
and 48 women; mean age, 67.7 years) who underwent
surgery for LDH or LSS between September 2017 andAugust 2019 were included to investigate the frequency ofpatients presenting with pre- and postoperative SIJ scoresof 4 points or greater.
Results: Six patients (four with LDH, two with LSS)
showed neurological symptoms and physical findings suggestive of SIJDs preoperatively, and the physical findingsof SIJDs in five of them were not detected after lumbar
surgery. The remaining one patient exhibited neurologicalsymptoms and back pain due to adjacent segment disease
after L2–S1 fusion, as well as pain in the superior posterior iliac spine bilaterally, which were temporarily relieved
after SIJ injections. Additional long fusion from Th10 to
the SIJ was performed, and the findings suggestive of SIJD
were not detected. Five patients (two with LDH, threewith LSS) presented with high SIJ scores postoperatively
for the first time, of which four were resolved with definitive diagnoses of SIJDs after SIJ injections.
Conclusions: High SIJ scores were found in 8.9% (11/124)of the patients, and definitive diagnoses of SIJDs weremade in 8.0% (10/124). In patients with high preoperative SIJ scores, a combination of lumbar spine disease and
SIJD should be suspected; however, if the neurologicalsymptoms are mainly due to lumbar spine disease, lum-

Asian Spine Journal
bar spine surgery should be prioritized. In some cases,
the neurological symptoms as well as the findings of SIJD
were not detected after lumbar surgery, which may havereflected the reduced burden on the SIJ. Before long spinal
fusion, the SIJ score should be examined to determine
whether the SIJ should be included in long fusion surgery.
New onset of SIJD may be possible when lower back pain
flares up postoperatively. The SIJ score is useful to differentiate between recurrent LDH and inadequate decompression, thus avoiding unnecessary reoperation.

PS-FP-2-43

Technical Pitfalls During Sacroiliac Joint
Arthrodesis for Patients with Sacral Dysmorphism Induced by Lumbosacral Transitional
Vertebrae
Daisuke Kurosawa1, Eiichi Murakami1, Hiroshi Ozawa2

S39

lateral. During the surgery, three kinds of remarkable pitfalls were found in four out of seven patients with LSTV
as follows. In the cases of a 34-year-old man with IIIb anda 39-year-old woman with IV, the most cranial sacral foramen was larger and irregularly round, and the nerve root
ran to the lateral side from the deformed foramen morethan usual. In these patients, a firm medial traction of thenerve root together with the psoas major muscle for the
purpose of attaching a plate and inserting screws on thesacrum side in the anterior approach could cause the temporary radiculopathy. For a 26-yar-old woman with a thinsacral alar due to IIIb, the most cranial screw penetrated
the anterior margin of the sacrum and caused nerve root
injury in the posterolateral approach. For a 35-year-old
man with Ib, the screw insertions via the posterior were
technically challenging due to the small sacrum body.
Conclusions: This study indicated three kinds of surgical pitfall in the SIJ arthrodesis for sacral dysmorphism
induced by LSTV. These facts will be valuable when surgeons perform SIJ arthrodesis for patients with LSTV.

1

Department of Orthopaedic Surgery, Low Back Pain and Sacroiliac Joint
Center, JCHO Sendai Hospital, Sendai, Japan2
Department of Orthopaedic Surgery, Tohoku Medical and Pharmaceutical
University School of Medicine, Sendai, Japan

Purpose: Lumbosacral transitional vertebrae (LSTV)
can cause sacral dysmorphism combined with sacroiliac
articular morphological changes. During the sacroiliac
joint (SIJ) arthrodesis/fixation through the anterior,posterolateral, or posterior approach, we have occasionally experienced technical pitfalls in patients with sacral
dysmorphism induced by LSTV. This study aims to report
some pitfalls during SIJ arthrodesis related with sacral
dysmorphism induced by LSTV.
Methods: We evaluated 44 consecutive patients (17 men
and 27 women; mean age, 44.9±13.6 years) who required
SIJ arthrodesis for their severe SIJ pain between November 2005 and July 2017. LSTV was evaluated based on
Castellvi’s classification. The incidence of any LSTV waschecked. The surgical records for the patients with LSTV
were reviewed.
Results: Out of 44 patients, LSTV was observed in 7
(15.9%); Castellvi’s type Ib in two, IIa in one, IIIb in three,
and IV in one. A total of 50 joints were fixed as follows: 21on the left side, 17 on the right side, and six bilateral. Regarding the surgical approach, 29 joints were fixed via theanterior, four via the posterolateral, seven via the posterior, and 10 via a combination of the anterior and postero-

PS-FP-2-48

Association between Lumbar Segmental
Mobility and Intervertebral Disc Degeneration
Quantified by Magnetic Resonance Imaging
T2 Mapping
Izaya Ogon1, Hiroyuki Takashima1, Yoshinori Terashima1,
Mitsunori Yoshimoto1, Tsuneo Takebayashi2,
Toshihiko Yamashita1
1Department of Orthopaedic Surgery, Sapporo Medical University School of
Medicine, Sapporo, Japan2
Department of Orthopaedic Surgery, Sapporo Maruyama Orthopaedic
Hospital, Sapporo, Japan

Purpose: The relation between segmental mobility and degree of lumbar degenerative change is still unknown. Thiscross-sectional study aimed to elucidate the association
between intervertebral disc degeneration and segmental
mobility in chronic low back pain using magnetic resonance imaging (MRI) T2 mapping.
Methods: Subjects comprised 60 patients (29 men, 31
women; mean age, 61.8±1.9 years; range, 41–79 years). T2
values of the anterior annulus fibrosus (AF), the nucleus
pulposus (NP) and the posterior AF were evaluated with
MRI T2 mapping. Facet joint degeneration was divided

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Asian Spine J 2021;15(Supplement 1):S1-S177

into 4 grades using MRI. We analyzed the correlation
between segmental mobility and T2 values of anterior
AF, NP and posterior AF using multiple linear regression
analysis adjusted for age and facet joint degeneration.
Results: The standardized partial regression coefficient of
the anterior AF, NP, and posterior AF T2 values were 0.125(p=0.72), 0.499 (p<0.01), and –0.026 (p=0.11), respectively, for the L1–2 level; 0.102 (p=0.27), 0.395 (p<0.01),
and –0.094 (p=0.20), respectively, for the L2–3 level; 0.108(p=0.38), 0.415 (p<0.01), and –0.050 (p=0.51), respectively, for the L3–4 level; 0.124 (p=0.09), 0.396 (p<0.01), and0.025 (p=0.73), respectively, for the L4–5 level; and 0.011(p=0.89), 0.443 (p<0.01), and 0.030 (p=0.72), respectively,
for the L5–S level. There was a significantly positive correlation between segmental mobility and the T2 valuesof NP at L1–L2, L2–L3, L3–L4, L4–L5, and L5–S1. No
significant correlations arose between segmental mobility
and the T2 values of the anterior AF and the posterior AF
at L1–L2, L2–L3, L3–L4, L4–L5, and L5–S1.
Conclusions: Characterization of the relationship between
NP degeneration and lumbar segmental mobility may enhance our ability to evaluate the changes seen in kinematics of functional spinal unit.

PS-FP-2-49

Diagnostic Performance of Conventional TwoDimensional Magnetic Resonance Image for
L5–S Foraminal Stenosis
Kohei Takahashi1,2, Myo Min Latt1, Takumi Tsubakino1,
Ko Hashimoto1,2, Toshimi Aizawa2, Yasuhisa Tanaka1
1

Tohoku Central Hospital, Yamagata, Japan
Tohoku University Hospital, Sendai, Japan

2

Purpose: Three-dimensional magnetic resonance images(3D-MRI) has been reported to be useful to diagnose
foraminal stenosis of the lumbar spine. Meanwhile, a conventional two-dimensional MRI (2D-MRI) is still used as
the first-choice scan, despite a lack of evidence for its diagnostic performance in detecting intraforamonal and/or
extraforaminal stenosis at L5–S segment. In this study, thediagnostic performance of 2D-MRI for foraminal stenosis
were assessed by comparing with separately scanned 3DMRI in the identical individuals.
Methods: Forty-six consecutive surgical cases with unilat-eral L5 radiculopathy due to L5–S foraminal stenosis were
included in this study (group F: 22 males and 24 females;mean age, 67 years; range, 25–75 years). The age andgender-matched 46 cases with unilateral L5 radiculopathy
due to L4–5 intracanal stenosis were randomly selected(group C: 22 males and 24 females; mean age, 67 years;
range, 25–75 years) as control. The sets of 2D- and 3DMRI obtained from the total of 92 subjects were assessedby two blinded expert spine surgeons in randomizedorder in 4-week interval. The examiners were informed
only of the laterality of the lesion in each patient, andasked to choose either of the following answers in each
set of images of each patient; “absence of foraminal stenosis”, “intraforaminal stenosis”, “extraforaminal stenosis”,“coincident intraforaminal”, and extraforaminal stenosis”.
Moreover, 2D- and 3D-MRI of randomly selected 10 cases
were assessed twice by one examiner in 3-month interval.
The intra- and interobserver reliability of 2D-MRI were
evaluated using the kappa (κ) statistics. Thereafter, thediscrepancies in interpretation on 2D- and 3D-MRI between two examiners were resolved by further discussion.
Then, sensitivity and specificity of 2D-MRI in diagnosis of
intraforaminal and extraforaminal stenosis was calculated,based on the premise that the evaluation by 3D-MRI is
correct.
Results: The κ values for intra- and interobserver agreement for 2D- and 3D-MRI ranged from 0.74 to 1.0,
respectively. By 3D-MRI, all the cases in group F werediagnosed to have foraminal stenosis (intraforaminal,
19; extraforaminal, 11; both, 16), and none in group C.
Sensitivity and specificity of 2D-MRI for intraforaminal
stenosis were 85.7 % and 87.7%, respectively, and for extraforaminal stenosis, 37 % and 98.5 %, respectively.
Conclusions: The diagnostic reliability and accuracy of
2D-MRI for intraforaminal stenosis seemed to be acceptable, but not for extraforaminal stenosis in our study. We
need to keep in mind that 2D-MRI is not necessarily reliable in diagnosing extraforaminal stenosis at L5–S.

Asian Spine Journal
PS-FP-2-50

The Longitudinal Analysis to Determine
Whether the Presence of Current Sexual Activities
Among Elderly People Affect Low Back Painor NotShoichiro Ohyama1, Masatoshi Hoshino2, Shinji Takahashi2,
Hidetomi Terai2, Yusuke Hori2, Akito Yabu2, Tadao Tsujio3,
Hiroaki Nakamura2
1

Department of Spine Surgery, Nishinomiya-Watanabe Hospital, Hyogo,Japan
2
Department of Orthopaedic Surgery, Osaka City University Graduate
School of Medicine, Osaka, Japan3
Department of Orthopaedic Surgery, Shiraniwa Hospital, Nara, Japan

Purpose: Japan is one of the most rapidly aging country in
the world. Low back pain (LBP) is the most frequent complaint among elderly in Japan, so LBP of the elderly is national burden. Exercise was reported to be effective for reduction of LBP among elderly patients. We hypothesizedthat sexual activity in the elderly might also be effective in
reducing LBP. However, there was no study which investigated the association between sexual activity and LBP
among elderly in Japan. The purpose of this study was to
examine whether the presence of current sexual activities
among elderly people affect LBP in future.
Methods: The subjects were 317 elderly people (aged ≥65
years; 130 males, 187 females) who participated in thelongitudinal survey of the health status for elderly population in Japan. Based on the results of questionnaires, weclassified those who had sexual intercourse within thepast year into sexually active group, and those who did
not have sexual intercourse in over a year into sexuallyinactive group. Baseline characteristics such as current
Visual Analog Scale (VAS) of LBP, physical decline (the25-question geriatric locomotive function scale [GLFS])
and marital status were compared between two groups.
We investigate whether sexual activity among elderly people affect LBP in future using multiple regression analysis
with the VAS of LBP in following year as the objective
variable and age, gender, body mass index, baseline VAS
of LBP, GLFS, marital status, and the presence of current
sexual activities as explanatory variables.
Results: Totally, 23.3% (n=74) of participants reported tohave current sexual activity. The current VAS of LBP was
significantly higher in the sexually inactive group thanactive group (22.8/12.4 mm, p<0.01), but just 0.8% (n=2)

S41

of participants reported that their sexual activity was absent due to LBP. The sexually active group showed thatthey were younger (72.5/75.5 years, p<0.01), less physicaldecline (GLFS: 5.7/11.5 patients, p<0.01), more males(59.5/35.4%, p<0.01), and more married (90.5/72.4%,
p<0.01). Multiple regression analysis showed that thepresence of current sexual activity independently affected
the VAS of LBP in following year (β= -6.24, p=0.01).
Conclusions: This is the first to investigate the relationshipof sexual activity and LBP among elderly in Japan. Our
results showed that the presence of sexual activity among
elderly people significantly affect the reduction of LBP.
Just as exercise is favorable treatment for LBP, maintaining
sexual activity in elderly may also be effective in reducing
LBP.

PS-FP-2-51

Unilateral Lumbar Interbody Fusion versus
Conventional Posterior Lumbar Interbody
Fusion for Two Lumbosacral Segments:
Clinical and Radiological Outcomes of 1-Year
Follow-up
Seung-Hyun Choi1, Sang-Kyu Son2, Weon-Wook Park1
1

Department of Orthopedic Surgery, ParkWeonWook Hospital, Busan, Korea
Department of Neurosurgery, ParkWeonWook Hospital, Busan, Korea

2

Purpose: This study compared clinical and radiologicaloutcomes of unilateral biportal endoscopic lumbar interbody fusion (ULIF) to those of conventional posterior
lumbar interbody fusion (PLIF) for two lumbosacral segments.
Methods: Fifty ULIF (age, 67±5 years) and 51 PLIF (68±8
years) patients for two lumbosacral segments followed
more than 1 year were selected. Parameters for surgical
techniques (operation time, whether transfused), clinicalresults (Visual Analog Scale [VAS] for back and leg pain,
Oswestry Disability Index [ODI]), surgical complications(dural tear, nerve root injury, infection, hematoma), andradiological results (cage subsidence, screw loosening, fusion) between the 2 groups were compared.
Results: The PLIF group demonstrated a significantly
shorter operation time and more transfusions done thanthe ULIF group. The VAS for leg pain in both groups andfor back pain in the ULIF group significantly improved at

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Asian Spine J 2021;15(Supplement 1):S1-S177

1-week follow-up, while the VAS for back pain in the PLIF
group significantly improved at 1-year follow-up. ODI
scores improved at 1-year follow-up in both groups. Complication rates were not significantly different between
groups. Fusion rates with definite and probable grades
were not significantly different between groups.
Conclusions: ULIF is less invasive while just as effective
as conventional PLIF in improving clinical outcomes andobtaining clinical fusion. However, ULIF has a longer operation time than PLIF. The authors suggest that the ULIF,
which is a minimally invasive procedure, is an alternative
treatment option for conventional PLIF.

PS-FP-2-53

How the Novel Modular Spine Blocks Affectthe Adjacent Lumbar Spine on Finite Element
Analysis?
Jui-Yang Hsieh1,2,3, Yi-You Huang1, Chen-Sheng Chen4,
Jyh-Horng Wang2, Po-Quang Chen2
1

Department of Biomedical Engineering, National Taiwan University, Taipei,
Taiwan2
Department of Orthopedic Surgery, National Taiwan University Hospital,
Taipei, Taiwan
3
Department of Orthopedic Surgery, National Taiwan University Hospital
Jinshan Branch, New Taipei, Taiwan
4Department of Physical Therapy and Assistive Technology, National YangMing University, Taipei, Taiwan

Study Design: Finite element model (FEM) study.
Purpose: To investigate whether novel modular spine
blocks (MSB) of various structural designs and implantation methods would alter the force distribution of thetreated segment, as well as disk stress and distribution ofrange of motion at the adjacent segments.
Overview of Literature: MSB is a novel device which canbe inserted and assembled within the treated vertebra
without requiring overly complex surgical techniques due
to its simplistic mechanical design. Open reduction andinternal fixation with MSB rather than augmentation withbone cement is an optimal alternative for treating vertebral compression fracture. However, little is known about
how the biomechanical effects the MSB might have on thetreated vertebrae.
Methods: A three-dimensional nonlinear FEM of the L3
implanted with MSB blocks was constructed. Various

structural designs (solid vs. hollow; 3-layered vs. 6-layered), implantation methods (unilateral vs. bilateral), andtheir effects were studied. The model was preloaded to
150 Nm before the effects of flexion, extension, torsion,and lateral bending were analyzed at the controlled rangesof motion of 20°, 15°, 8°, and 20°, respectively. Resultant
intervertebral range of motion and disc stress, as well as
intravertebral force distribution are analyzed at the adjacent segments.
Results: The MSB blocks provided similar levels of stability at the adjacent segments regarding intervertebral rangeof motion and disc stress. Under stress tests, the force distribution of the solid MSB blocks was shown to be evenly
distributed within the vertebrae. The maximum stressvalue observed of the hollow, three-layered, unilaterally
implanted MSBs is generally lower compared to that ofsolid, six-layered, bilaterally implanted MSBs.
Conclusions: The MSB blocks do not interfere with the interverbral range of motion and creates no additional loading to the adjacent discs. The overall stabilization effectof the unilaterally implanted hollow three-layered MSBs
blocks is not inferior to that of the bilaterally implanted
solid six-layered MSB blocks.

PS-FP-2-54

Epidemiology and Burden of Osteoporotic
Patients with Spine Fusion Procedures with
Pedicle Screws in Japan: A Nationwide Claim
Database Analysis
Kotaro Nishida1, Anh Bourcet2, Mami Ogiri3,
Hye Jin Park4, Kazuko Nishikawa5
1

Department of Orthopedic Surgery, Graduate School of Medicine, Universityof the Ryukyus, Nishihara, Japan
2
Health Economics and Market Access, Johnson & Johnson Medical,
Singapore3
Health Economics and Market Access, Johnson & Johnson Medical KK,
Nishihara, Japan
4
Health Economics and Market Access, Johnson & Johnson Medical, Seoul,
Korea
5
Medical Affairs, Johnson & Johnson Medical KK, Nishihara, Japan

Purpose: This study aims to describe the epidemiologyof patients undergoing spinal fusion surgery with pedicle
screws in Japan, their post-operative outcomes and theimpact of osteoporosis.

Asian Spine Journal
Methods: Patients ≥18 years old who had spine fusion
procedures with standard pedicle screws between 2010–2017 were identified using the Medical Data Vision Co.,
Ltd. (Tokyo, Japan) claim database. Osteoporotic patientswere identified with diagnostic code M80, M81, or/and
receipt of osteoporotic medication. Additional fixation
instruments of interest were hooks, wires, hydroxyapatite
coating stick, calcium phosphate bone/cement. Baselinecharacteristics, complications, re-admissions, spinerelated re-operations, length of stay (LOS), and healthcare
expenditures were extracted. Descriptive statistics andmultivariable analysis were calculated to assess these endpoints.
Results: We identified 22,930 patients meeting the study
criteria. Mean age was 67.3 years old and 51.22% weremale. Osteoporotic patients represented 23.06%, with amean age of 73.8±8.58 years and mainly female (76.6%).
The incidence of osteoporosis has increased by 67% from2010 to 2016. Additional fixation instruments were required in 22.3% of osteoporotic patients vs. 10.9% of theoverall population, with wires most used. In comparison
with non-osteoporotic population, osteoporotic patients
showed statistically significant higher rate of mechanicalfailures (1.2% vs. 0.6%, p<0.001) and reoperations (9.0%
vs. 6.1%, p<0.001) at 24-month post-surgery. The median
LOS (interquartile range) and inpatient total cost werehigher with 26.0 days (19.0–42.0) vs. 21.0 (16.0–31.0)
and 3.44 million Japanese yen (JPY) (2.59–4.77) vs. 2.70
(2.20–3.62). These poor bone quality patients would receive more often additional fixation instruments. In particular, 11.2% osteoporotic patients use wires in addition
to pedicle screws, compared to 5.1% of non-osteoporotic
patients; and 8.2% use hydroxyapatite coating stick vs.
3.0%, respectively. Despite these additional fixations, osteoporotic patients still showed statistically higher riskof spine related re-operation (11.9% vs. 8.21%, p<0.001),
longer LOS (median 34.0 vs. 24.0, p<0.001), and higher
total cost (4.45 vs. 3.19 million JPY, p<0.001) compared tonone. The multivariable analysis showed that factors likethe complexity of the spinal fusion, osteoporosis, need for
additional fixations, and renal failures are significantly associated with re-operations rates within 24 months postsurgery.
Conclusions: This first nationwide real-world claims database study highlighted an increasing burden of osteoporotic patients undergoing spine fusion surgeries in Japan.
They had higher rates of postoperative complications andS43

reoperation than non-osteoporotic patients, even with additional fixations. The LOS is higher and incurred higher
total healthcare expenditures. This underscores the needfor improved spinal fixation for this high-risk patientgroup.

PS-FP-2-55

Short Segmental Lumbar Surgery Improves
Health-Related Quality of Life without Limiting
Activities of Daily Living: A Retrospective Study
Ryota Kimura, Naohisa Miyakoshi, Michio Hongo,
Yuji Kasukawa, Daisuke Kudo, Yoichi Shimada
Department of Orthopedic Surgery, Akita University Graduate School of
Medicine, Akita, Japan

Purpose: Lumber surgery improves the postoperative
quality of life (QOL), but activities of daily living (ADL) is
limited in long fusion. In the case of short segmental fusion, the effect on postoperative ADL is considered to besmall, but there have been few reports and no comparison
was made before and after the operation. To compare preand postoperative ADL and QOL between lumbar shortfusion and decompression.
Methods: Two hundred seventy-two patients who underwent surgery filled self-administered questionnaires (1year preoperative and postoperative conditions), and 102
patients (the fusion group [F group] 53 cases, the decompression group [D group] 49 cases) participated in the
study. ADL such as socks, nail clippers, and deep bows,
etc. and manual work such as snow shoveling, weeding,and farming, etc. were examined. The Reflux Disease
Questionnaire (RDQ), the 36-item Short Form Health
Survey (SF-36: physical component summary [PCS],
mental component summary [MCS], role/social component summary [RCS]), and spinal alignments were evaluated. Pre- and postoperative conditions were statisticallycompared.
Results: There were no significant differences between thetwo groups in age, sex, and the number of operation levels,
ADL, and QOL. RDQ (the F group 10.8→6.8, the D group11.0→6.8), PCS (the F group 26→34, the D group 26→32),
and MCS (the F group 51→54, the D group 47→54) significantly improved in both groups postoperatively. RCS
was significantly improved only in the D group (35→41).

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Asian Spine J 2021;15(Supplement 1):S1-S177

ADL tended to improve compared to preoperatively. In
manual labor, the number of people who performed farming increased postoperatively, and the number of people
who weeded and plowed snow decreased, but there is no
significant difference between pre and postoperation. The
spinopelvic sagittal parameters were not significantly different between the two groups pre and postoperation.
Conclusions: Short segmental lumbar surgery did notchange ADL and improved QOL. The fixation had equivalent ADL and QOL to those after decompression, andthere was no restriction due to fixation. Short-segmental
lumbar surgery can be selected according to the patient’s
condition because the ADL required after surgery does
not change depending on the surgical procedure.

PS-FP-2-56

Coronal Magnetic Resonance Imaging for
Diagnosis of Lumbar Foraminal Stenosis:
A Comparative Study of Reliability,
Reproducibility, and Interpretation between
T1 and T2-Weighted Images
Ko Hashimoto1, Yasuhisa Tanaka2, Toshimi Aizawa1,
Takumi Tsubakino2, Tomowaki Nakagawa3,
Satoshi Tateda4, Kohei Takahashi1, Manabu Suzuki1,
Takahiro Ohnoki1, Naoki Morozumi5, Yutaka Koizumi5,
Tetsuro Sato3, Hiroshi Ozawa6, Haruo Kanno6,
Shoichi Kokubun5, Eiji Itoi6
1

Department of Orthopaedic Surgery, Tohoku University Graduate School of
Medicine, Sendai, Japan2
Department of Orthopaedic Surgery, Tohoku Central Hospital, Sendai,Japan
3
Sendai Orthopaedic Hospital, Sendai, Japan
4
Department of Orthopaedic Surgery, Ishinomaki Red Cross Hospital,
Ishinomaki, Japan
5
Department of Orthopaedic Surgery, Sendai Nishitaga Hospital, Sendai,Japan
6
Department of Orthopaedic Surgery, Tohoku Medical and Pharmaceutical
University, Sendai, Japan

Purpose: As for imaging diagnosis of lumbar foraminal stenosis, T2-weighted coronal magnetic resonanceimaging (MRI) of the lumbar spine, such as magnetic
resonance–myelography has been mainly reported. Meanwhile, our group has been utilizing T1-weighed coronal
imaging which seemed to distinguish nerve root andnerve-compressing factors easier. To date, there has been

no study compared the reliability or reproducibility between T1- and T2-weighted images objectively. This study
aims to compare the reliability, reproducibility, and thefeatures of diagnostic trends between T1- and T2-weighted lumbar coronal MRI.
Methods: The patients planned for posterior decompression surgery for unilateral L5 radiculopathy were prospectively registered. T1- and T2-weighted lumbar coronal
MRI was obtained from each patient preoperatively. The
patients who had immediate neurological improvement
after posterior decompression surgery were includedin this study as following: (1) 22 patients with L4–5 intracanal stenosis who underwent ipsilateral intracanal
decompression (fenestration) and (2) 22 patients with
L5–S foraminal stenosis who underwent ipsilateral lateral decompression. The lumbar coronal MRI of these 44
patients were assessed twice by five expert spine surgeons
independently in random order with considerable timeinterval, for absence/presence of foraminal stenosis, andthe side and the feature of stenosis when the examiner(s)judged as foraminal stenosis. Also, T1- and T2-weighted
coronal MRI were compared about (1) the diagnostic accuracy, (2) intra- and inter-observer agreement by kappa(κ) statistics in round-robin of five examiners ×2 trials,
and (3) nerve compression factor(s) judged for foraminal
stenosis, for diagnosis of L5–S foraminal stenosis.
Results and Conclusions: On diagnosis of L5–S foraminal
stenosis by lumbar coronal MRI, the accuracy of T1- andT2-weighted images (WI) were 73.4% and 70.0%, respectively. The mean κ-values of T1- and T2-WI were 0.815
and 0.699 for intra-observer agreement (p=0.039), and
0.639 and 0.595 for inter-observer agreement (p=0.002),
respectively. The intra- and inter-observer agreement weresignificantly higher in T1-WI. In the 12 patients with L5–
S foraminal stenosis of which the accuracy rates were≥80% both in T1- and T2-WI, swollen nerve root and disc
protrusion were detected more sensitively in T1-WI. In
the nine patients with L4–5 intracanal stenosis of which
the accuracy rates were ≤50% both in T1- and T2-WI (i.e.,
misconceived as foraminal stenosis), there was no difference in misconceived nerve compression factors (falsepositive) between T1 and T2-WI.

Asian Spine Journal
PS-FP-2-58

Intradiscal Vacuum Phenomenon: Radiological
Factors to Predict the Selective Appearance anda New Morphological Classification System
Swapnil Sanjay Hajare, Rishi Kanna, S. Rajasekaran,
Ajoy Shetty
Department of Spine Surgery, Ganga Hospital, Coimbatore, India

Purpose: Intradiscal vacuum phenomenon (IDVP), thoughfrequently observed in the spinal radiographs, very littel
has been known about its pathophysiology and lacks a patient-oriented classification system required for documentation, referral, and research. We studied the radiologicalfactors associated with the selective appearance of IDVP
to understand the pathophysiology and evaluated a novel
classification system.
Methods: We performed a retrospective case-control
study on patients with low back pain with or without
radiculopathy and divided them into cases and controls
based on the presence of IDVP in the lumbar discs. Thebase demographic factors, radiographic factors including
eccentric disc space narrowing and coronal listhesis onanteroposterior view, levels affected, diagnosis, sagittal angular motion difference (SAMD), and sagittal translational motion difference (STMD) on lateral stress views were
documented. Magnetic resonance imaging evaluated for
Pfirrmann grading, anterior longitudinal ligament (ALL)disruption, Modic changes, and IDVP signal intensity.
IDVP was categorized into three major types (dot, linear,and dense) and five sub-types (anterior, middle, posterior,
partial, and Pan), based on the morphology and locationof vacuum phenomenon.
Results: Total 1,049 patients formed the study population,and 28.4% (295) patients had IDVP. Presence of IDVP
was found to be significantly associated with older age (>60
years, p<0.001), eccentric disc space narrowing (26.3%,
p<0.001), coronal listhesis (7.1%, 0.001), all disruption(32.2%, p<0.001), higher Pfirrmann grade (≥3, p<0.001)
and type II Modic changes (68.9%, p<0.001), and higher
SAMD (10.81±4.61, p<0.001). STMD was significantly
less than the control group (0.88±1.31, p<0.001), but on
sub-group analysis, the dense type had significantly more
STMD (0.89±1.51, p<0.001) than a dot and linear type.
IDVP was divided into three types based on morphology:
dot (21.8%), linear (30.9%), and dense (47.4%). The dot

S45type was further divided into anterosuperior (19.21%)
and anteroinferior (2.7%). The dense type was subdivided
into anterior (10.9%), middle (25.8%), posterior (1.6%),
partial (4%), and Pan (5.1%). The dens type had significant correlation with coronal listhesis (12.7%, p<0.001),
higher SAMD (12.3±4.26), STMD (0.89±1.51, p<0.001),
and Pfirrmann grade.
Conclusions: The prevalence of IDVP was 28.4%. Irrespective of the primary lumbar disease, critical radiographic features including eccentric disc space narrowing,coronal listhesis, higher SAMD and STMD, all disruption,higher Pfirrmann grade, and Modic changes were essential for the development of IDVP. Dense type is common
in patients with spinal instability, while dot and linear
were noted more disc degeneration. IDVP needs to be
categorized for documentation, research, and evaluating
significance, and the novel morphology-based classification would guide it. These positive findings provide new
insights and strengthen our understanding of IDVP.

PS-FP-2-60

The Characteristics of Degenerative Disc
Disease: Pfirrmann versus Thompson Grading
Systems
Kamil Krupa1,2, Dominik Taterra1,2, Przemysław Pękala1,2,
Mateusz Paziewski1,2, Wadim Wojciechowski1,
Tomasz Konopka1, Jerzy Walocha1, Krzysztof Tomaszewski2,3
1

Jagiellonian University Medical College, Cracow, Poland
International Evidence-Based Anatomy Working Group (iEBA-WG),
Kraków, Poland
3
Faculty of Medicine and Health Sciences, Andrzej Frycz Modrzewski
Kraków University, Kraków, Poland
2

Purpose: Intervertebral disc (IVD) degeneration is considered to be one of the main pathophysiological causes oflow back pain. Several grading systems have been developed for both morphological and radiological assessment.
The aim of this study was to assess the morphological andradiological characteristics of IVD degeneration and validate popular radiological Pfirrmann scale against morphological Thompson grading system.
Methods: Full spinal columns (vertebrae L1–S1 and IVD
between them) were harvested from cadavers through ananterior dissection. Magnetic resonance imaging scans of
all samples were conducted. Then, all vertebral columns

S46

Asian Spine J 2021;15(Supplement 1):S1-S177

were cut in the midsagittal plane and assessed morphologically.
Results: A total of 100 lumbar spine columns (446 IVDs)
were included in the analysis of the degeneration grade.
Morphologic Thompson scale graded the majority of discs
as grade 2 and 3 (44.2% and 32.1%, respectively), followed
by grade 4 (16.8%), grade 1 (5.8%), and grade 5 (1.1%).
The radiologic Pfirrmann grading system classified 44.2%
of discs as grade 2, 32.1% as grade 3, 16.8% as grade 4, 5.8%
as grade 1, and 1.1% as grade 5. The analysis on the effect of age on degeneration revealed significant, althoughmoderate, positive correlation with both scales. Analysisof the agreement between scales showed weighted Cohen’s
kappa equal to 0.61 (p<0.001). Most of the disagreement
occurred due to a 1-grade difference (91.5%), whereas
only 8.5% due to a 2-grade difference.
Conclusions: With the increase of the prevalence of intervertebral disc disease in the population, reliable grading systems of IVD degeneration are crucial for spine
surgeons in their clinical assessment. While overall there
is agreement between both grading systems, clinicians
should remain careful when using Pfirmann scale as thegrades tend to deviate from the morphological assessment.

PS-FP-2-61

Efficacy of Caudal Neuroplasty versus
Transforaminal Epidural Block for Radiating
Pain Caused by Lumbar Foraminal Stenosis
Jihun Park

underwent neuroplasty or TFEB for spinal stenosis andresponded to the questionnaire survey. Neuroplasty and
TFEB were divided into groups 1 and 2, respectively. In
neuroplasty, the dye was confined only within the spinal
canal as group 1a, and the dye was contrasted to the root
as group 1b. In TFEB, the dye was penetrated into the canal as group 2a, and the dye only confined to the root asgroup 2b. Visual analog scale (VAS), Oswestry Disability
Index (ODI), and EuroQol five-dimension (EQ5D) were
followed for 6 months.
Results: Both groups 1 and 2 improved VAS, ODI, andEQ5D in final result. In both groups, VAS improved on
the day 3, and in group 2 maintained improvement at 1
week, 1 month, and 6 months. Group 1 maintained improvement at 1 week and 1 month, but little worsening at
6 months. In the comparison between group 1 and group 2,
VAS at 1 week and 1 month was lower in group 1, but at 6
months VAS was not different from group 2. There was nodifference between groups 1a and 1b. There was no difference between group 2a and group 2b, but in VAS on day
3, although not statistically significant, group 2a was low(p=0.74). When group 2a and group 2b were comparedwith group 1 respectively, 2a showed difference only in
VAS on day 3, whereas group 2b showed significant difference in VAS on day 3, week 1, and month 1.
Conclusions: Neuroplasty showed lower VAS in early period than TFEB regardless of dye pattern. However, at 6
months, there was no difference from TFEB. In TFEB, thepattern of dye penetrated into the canal showed more lessdifference from neuroplasty.

PS-FP-2-62

Department of Orthopeadics, Kwangju Christian Hospital, Gwangju, Korea

Purpose: Neuroplasty and trans-foraminal epidural block(TFEB) are representative procedures performed to relieve
symptoms of spinal stenosis. In both procedures, radiocontrast dye is injected in order to identify the site of medicine
administration. At this time, the dye shows various distribution patterns, but there were not many studies havebeen conducted on how the difference in the distribution
pattern makes a difference in the treatment outcome. The
purpose of this study was to divide the distribution patterns of radiocontrast dyes during neuroplasty and TFEB
and to find out what differences in treatment results.
Methods: The study was conducted on patients who

Risk Factors Associated with Low Back Pain in
Patients with Osteoporosis
Yusuke Mimura, Masayuki Miyagi, Kosuke Murata,
Tomohisa Koyama, Akiyoshi Kuroda, Ayumu Kawakubo,
Yuji Yokozeki, Eiki Shirasawa, Wataru Saito,
Takayuki Imura, Toshiyuki Nakazawa, Gen Inoue,
Masashi Takaso
Department of Orthopaedic Surgery, Kitasato University, School of Medicine,
Sagamihara, Japan

Purpose: Patients with osteoporosis often experience lowback pain (LBP) despite no evidence of new compression

Asian Spine Journal
fractures. We performed multivariate analyses to identify
factors that may affect LBP.
Methods: The data of 491 patients with osteoporosis wereretrospectively reviewed. Data included patient age, sex,
body mass index (BMI), bone mineral density of thelumbar spine, tartrate-resistant acid phosphatase 5b level(TRACP5b), trunk muscle mass (TM), sagittal verticalaxis (SVA), existing vertebral fractures, secondary osteoporosis, Controlling Nutritional Status score, pain-relateddisorders (PD) and gait disturbance (GD) scores from theJapanese Orthopedic Association Back Pain Evaluation
Questionnaire (JOABPEQ), Oswestry Disability Index(ODI) scores, and Visual Analog Scale (VAS) scores for
LBP. Patients with scores of 100 for each subsection of the
JOABPEQ, ODI scores <12, or a VAS score <1 cm wereconsidered to not have LBP (LBP [-] group). Multivariate
analyses were used to determine variables associated with
LBP.
Results: LBP defined by PD was associated with aging,high BMI, and high SVA. Aging, high TRACP5b, high
BMI, low TM, high SVA, and more vertebral fractures
were associated with LBP defined by GD. LBP defined by
ODI score was associated with high BMI, low TM, high
SVA, and more vertebral fractures, and LBP defined by
VAS score was associated with high BMI, high SVA, andmore vertebral fractures.
Conclusions: Aging, high bone turnover, obesity, low TM,
spinal global sagittal malalignment, and a high numberof VFs were potential independent risk factors of LBP inpatients with osteoporosis. Especially, all factors of LBP
scores including PD and GD for JOABPEQ, ODI score,
and VAS score for LBP were associated with s spinal
global sagittal malalignment and obesity. However, bonemineral density (BMD), secondary osteoporosis, and nutritional status were unrelated to LBP scores. Other thanpharmacotherapy to increase BMD, exercise therapy totreat low muscle mass, spinal global sagittal malalignmentand obesity may prove effective in improving ADL due to
LBP in osteoporosis.

S47

PS-FP-2-66

Spinopelvic Parameters and Symptomatic
Lumbar Degeneration in Nepalese Patients
Rabindra L. Pradhan, Bimal K. Pandey, Syed Saddam
Kathmandu Medical College Teaching Hospital, Kathmandu, Nepal

Purpose: Degenerative lumbar spine disease such as spondylolisthesis, lumbar disc herniation (LDH), and lumbar
spinal stenosis (LSS) may be associated with different spinopelvic parameters. The load distribution and function
may play a role in different pelvic anatomy and may besusceptible to development of spinal degeneration.
Methods: Patients with symptomatic lumbar spinal degeneration who presented to KMCTH from July 2018 to June
2020 were included in this cross-sectional observational
study. Degenerative pathologies were classified as LDH,
LSS, and degenerative spondylolisthesis (DSPL). The
anatomic pelvic parameters pelvic incidence (PI), pelvic
radius (PR), and sacral table angle (STA) were assessed inlateral radiographs and compared between pathologies.
Results: Two hundred and six fulfilled all inclusion criteria and were analyzed with mean age 51.61 years (range,
23–87 years). The mean PI for women (57.23°±3.24°)
was significantly larger (p=0.005) than that for men(56.19°±1.59°). No sex differences were found with regard to PR (p=0.198) and STA (p=0.859). For all threepelvic parameters, group comparisons revealed significant intergroup differences. The mean±standard
deviation PR was the smallest in the DSPL group(127.7255±1.93762), followed by LDH (136.6273±2.88mm). The mean PR was highest in the LCS group(144.3751±6.33742 mm). The smallest value for the mean
PI was observed in the LDH group (56.2975°±2.45875°),
followed by LCS (57.1080°±2.56002°). The highest
value for the mean PI was observed in the DSPL group(58.9295°±2.14364°). The smallest STA was foundin the LDH group (93.6272°±2.49396°), followed by
DSPL (96.8848°±1.03689°). The mean STA of LCS was
103.3458°±3.93079°.
Conclusions: Our study showed all anatomic parameters
to be specific for distinct types of degeneration, whichsuggest pelvis shape may be a predisposing factor for theirdevelopment. This study presents the various spino-pelvic
radiographic parameter values of a sample of the symptomatic Nepalese population. The role of PR and STA

S48

Asian Spine J 2021;15(Supplement 1):S1-S177

defining pelvic shape as a predictor of spinal shape, load,
and function may have a role in the lumbar degeneration
process.

PS-FP-2-70

Is Sagittal Spinopelvic Imbalance a Critical
Factor for Revision Hip Arthroplasty?
Cheng-Min Hsu1, Yu-Cheng Yeh1, Yu-Chih Lin1,
Tsung-Ting Tsai1, Yu-Han Chang1, Pang-Hsin Hsieh1,
Po-Liang Lai1, Chi-Chien Niu1, Hsin-Nung Shih1,
Lih-Huei Chen1, Steve W. N. Ueng1, Wen-Jer Chen2
1

Department of Orthopedic Surgery, Chang Gung Memorial Hospital,
Taoyuan, Taiwan
2
Department of Orthopedic Surgery, Chung Shan Hospital, Taipei, Taiwan

Purpose: The spine-pelvis-hip complex has been recognized as a double-hinged system in postural changes fromsitting to standing. Therefore, the orientation of total hip
arthroplasty (THA) and spinopelvic alignment was closely
related to each other. Previous studies demonstrated that
lumbar spine fusion (LSF) prior to THA had an increased
risk of dislocation and subsequent revision compared tothose without prior LSF. This retrospective cohort study
aims to determine if the surgical sequence of THA andLSF or the spinopelvic alignment affect the prognosis of
THA in patients with both hip and lumbar spine pathology.
Methods: We included 76 patients receiving LSF, primaryand revision THA in branches of Chang Gung Medical
Foundation during 1995–2018. Patients lacking preoperative or postoperative images or receiving less than 2 years
follow-up were excluded. The primary outcome was THA
survivorship and dislocation rate. The index operations
sequence and the radiographic parameters of spinopelvicalignment (pelvic incidence [PI], sacral slope, pelvic tilt
[PT], lumbar lordosis [LL], spinopelvic harmony [PI–LL],
THA cup inclination, and anteversion) were comparedfor primary outcomes. The included patients were divided
into three groups based on surgical sequence, where LSF
performed before, between, and after the primary andrevision THA were designated as SHH, HSH, and HHS,
respectively. As for the statistics, log-rank test and Cox
proportional hazard model were utilized for survivals. The
comparisons were analyzed via chi-square and KruskalWallis according to the scale and distribution of the data.

Results: The index operations sequence showed no differences in radiographic parameters or dislocation rates,
while the THA survivorship in SHH (median, 19 months)
were significantly shorter than HSH (p<0.05; median, 124months) and HHS (p<0.005; median, 89 months) groups.
For the effect of spinopelvic alignment, patients with THA
in retroverted pelvis (PT >20°) had a higher dislocation
rate (p<0.01) compared to normal pelvic version, while
different pelvic morphologies showed no differences in
dislocation rate. There were no differences in terms of
THA survivorship in different spinopelvic alignment.
Conclusions: Different surgical sequences of THA andLSF had comparable radiographic parameters and dislocation rates. However, LSF as the index procedure prior
to primary and revision THAs showed the shortest THA
survivorship in this study. Spinopelvic harmony may playa role in THA stability since THAs placed in retroverted
pelvis (PT >20°) had significantly higher dislocation rate.

PS-FP-2-72

Prevalence and Clinical Correlation of Lumbosacral Transitional Vertebra: An Ambi-Spective
Study Based on 4,027 Whole Spine Magnetic
Resonance Imaging
Swapnil Sanjay Hajare, Ajoy Shetty, S. Rajasekaran
Department of Spine Surgery, Ganga Hospital, Coimbatore, India

Purpose: Lumbosacral transitional vertebra (LSTV) evenbeing a commonest congenital anomaly of the lumbosacral (LS) spine, its reported prevalences vary widely;because the majority of studies are based on radiographs
alone. We evaluated 4,027 whole spine magnetic resonance imaging (MRI) to find a true prevalence of LSTV
and its association with degenerative disc disease andback pain.
Methods: A total of 4,027 patients qualifying inclusion
criteria were further subdivided into group A (n=2,011,
trauma) and group B (degenerative) patients. Group B
subdivided into B1 (n=1,009, predominant back pain) andB2 (n=1,007, predominant radicular pain) patients. The
sacralized and lumbarized vertebrae were classified using
the Castellvi’s (on plain anteroposterior LS radiographs)
and O’Driscoll’s (on sagittal whole spine MRI) classifications, respectively. MRI further evaluated for disc degen-Asian Spine Journal
eration of last three mobile segments (Pfirmman grading),
facet trophism of last most caudal well-formed facet, andtotal end plate (TEP) score was evaluated in last mobile
segment.
Results: Total prevalence of LSTV was 11.6% and wasmore common in group B2 (17.3%) followed by B1(14.8%) and A (11.6%). Castellvi’s type 2A (31.35%) was
the most common classification followed by 3B (25.85%).
By O’Driscoll’s classifications type 4 (70%) was most common followed by type 3 (23%). TEP score was significantly
more in sacralized patents (4.07±1.71) compared to lumbarized (3.81±1.61) and non-LSTV patents (3.96±1.59)of the B1 group; however, the B2 group had no significant
difference. Similarly, the sacralized patients had significantly more facet trophism compared to lumbarized andnon-LSTV patents in both B1 and B2 groups.
Conclusions: Total prevalence of LSTV was 13.8% andCastellvi’s type 2A was the most common type. The incidence of LSTV is high in patients with radiculopathy(17.4%) than with low back pain (14.9%). The disc immediately caudal to transitional vertebra is most significantly
affected by the degeneration of discs.

PS-FP-2-73

Efficacy of Analgesic Cocktail on Epidural
Patch for Postoperative Pain Control in Posterior
Surgery of Degenerative Lumbar Spine:
Randomized Control Trial Study
Surawut Ruchirawan, Satawat Jirapan
Spine Unit, Department of Orthopaedic, Buddhachinaraj Hospital, Nai
Mueang, Thailand

Purpose: Posterior lumbar surgery was an increase, andmany patients got significant postoperative pain problems.
Opioid drugs were commonly used for postoperative pain
control but complications from opioid usage commonlyoccurred. Multimodal analgesia was the option for postoperative pain control and avoid the complication from
opioid drugs used. Intraoperatively, we used absorbablegelatin mixed with analgesic drugs (Parecoxib and Bupivacaine) apply to epidural space for postoperative pain
control. The aims of this study are to study the efficacy of
Parecoxib and Bupivacaine combination compare with
Bupivacaine alone on epidural gelatin patch in terms of

S49

pain score reduction and to study the efficacy of Parecoxib
and Bupivacaine combination compare with Bupivacaine
alone on epidural gelatin patch in term of morphine use
reduction.
Methods: Sixty patients who were diagnosed degenerative spinal disease from Dec 2017 to April 2020. The
patients were diagnosed by physical examination, plainradiograph, and magnetic resonance imaging. The study
sample was divided into two groups: (1) Bupivacaine
plus Parecoxib (study group) and (2) Bupivacaine alone(control group). Study group: Absorbable gelatin patch
1 piece+0.5% Bupivacaine 0.6 mL+normal saline 0.4
mL+Parecoxib 40 mg (2 mL) apply on epidural spaceat laminectomy site. Control group: Absorbable gelatin
patch 1 piece+0.5% Bupivacaine 0.6 mL+normal saline
0.4 mL apply on epidural space at laminectomy site. All
patients were used intravenous patient-controlled analgesia morphine for morphine consumption record, Visual
Analog Scale (VAS) score, and complications at 8, 24, and48 hours postoperatively.
Results: A study group (n=30) and a control group (n=30)
were included. Demographic data were not statisticallysignificant. Postoperatively, morphine consumption in the
study group was less than control group statistically significant. VAS pain score in the study group was less thancontrol group statistically significant. Complications suchas dizziness, nausea, and vomiting were similar in the twogroups. No statistically significant.
Conclusions: Postoperative pain from spinal surgery wasan important problem. Many complications from opioid
drug usage such as dizziness, nausea, vomiting, and respiratory depression frequently occur. Multimodal analgesia
was used to reduce morphine consumption, postoperative
pain score, and complications from opioid drugs used. In
this study, the gelatin patch nonsteroidal anti-inflammatory drugs (NSAIDs) on epidural space can reduce morphine consumption, VAS pain score statistically significant. The gelatin patch NSAIDs on epidural space was aneffective optional multimodal analgesic tool to control the
postoperative pain and avoid the adverse event of opioid
usage for patients who underwent posterior surgery fordegenerative lumbar spinal surgery.

S50

Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-2-74

Effect of 3-Months of Romosozumab Treatment
on Spinal Surgery: Prospective Study Using
Finite Element Analysis
Koji Ishikawa, Soji Tani, Koki Tsuchiya,
Chikara Hayamawa, Ryo Yamamura, Akira Matsuoka,
Hiroshi Maruyama, Toshiyuki Shirahata, Yoshifumi Kudo,
Tomoaki Toyone, Katsunori Inagaki
Department of Orthopaedic Surgery, Showa University School of Medicine,Tokyo, Japan

Purpose: Romosozumab is a monoclonal antibody that inhibits sclerostin and rapidly increases bone mineral density (BMD) through a dual effect on bone by increasingbone formation and decreasing bone resorption. Several
studies showed the efficiency of osteoporosis treatment inpatients undergoing spinal surgery. However, no studies
have been performed to elucidate the effect of Romo during spinal surgery. The present study aimed to investigate
the effect of Romo on spinal surgery using quantitative
computed tomography (CT) based finite element analysis(FEA).
Methods: Consecutive 25 patients with postmenopausal
osteoporosis, scheduled for Romo treatment, were included for the prospective study. All patients were analyzed using bone turnover markers (TRACP-5b and total-P1NP)
and dual-energy X-ray absorptiometry for 6 months. To
better understanding of early effects of Romo, the spinal
fixation model of FEA has been developed based on CT
data. The models of the implant were created separatelyfrom high solution micro-CT and inserted in the vertebra
FEA model. Screw fixation, cage subsidence stress, andcompression force of vertebra were assessed following 3
months of Romo treatment.
Results: Twenty-two patients (mean±standard deviation age, 73.1±6.0 years) completed a 6-month followup with no fracture events. Romo treatment significantly
increased the levels of total-P1NP and reduced the levelsof TRACP-5b (p<0.01, vs. baseline: by Wilcoxon). The
percent changes of spine-BMD increased significantly
from baseline to 6 months (6.1%, p<0.01, vs. baseline: by
Wilcoxon). Notably, in FEA analysis, all the biomechanical parameters improved rapidly after 3 months of Romo
treatment (screw fixation: 21.5%, cage subsidence stress:
16.7%, compression force: 11.0%).

Conclusions: In summary, our prospective biomechanicalstudy using FEA revealed 3 months of Romo treatment
was effective in spinal fixation surgery. Romo may be useful for perioperative management to decrease complications.

PS-FP-3-1

Proposal of New Classification and Treatment
Strategy for Transverse Fractures of the C2
Body
Jong-Beom Park1, Sung-Kyu Kim2
1

Department of Orthopaedic Surgery, College of Medicine, The Catholic
University of Korea, Seoul, Korea
2
Department of Orthopaedic Surgery, Chonnam National University
Hospital, Gwangju, Korea

Purpose: To investigate the characteristics of transverse
fractures of C2 body diagnosed on sagittal computed tomography (CT) and to propose new classification and appropriate treatment strategies.
Methods: We classified 49 transverse fractures of C2 body
into three types based on fracture trajectories involving
superior articular facet (SAF) and lateral cortex (LC) of
C2 body on coronal CT and analyzed their characteristics
and treatments as follows: type 1, involvement of C2 SAF
on both sides; type 2, unilateral involvement of C2 SAF
on one side and LC on the other side; and type 3, involvement of LC on both sides. The characteristics, treatment
methods, and results of 49 transverse fractures of the C2body were analyzed.
Results: The mean age of the patients was 60.8 years.
Twenty-six patients were male, and 23 patients were female. Twenty-six patients were type 1, 21 were type 2,
and two were type 3. Correlation coefficients for intraobserver and inter-observer reliabilities for classification
were 0.723 and 0.598 (both, p<0.001), respectively. About
40.8% (seven type 1 and 13 type 2) of the patients had
fracture displacement >3 mm; Incidence of fracture displacement >3 mm was higher in type 2 than type 1 (61.9%
vs. 26.9%, p<0.05). About 79.6% (20 type 1, 17 type 2,
and two type 3) of the patients were treated conservatively, and 20.4% (six type 1 and four type 2) underwent
surgery. At last follow-up, 47 out of 49 patients achieved
fusion; overall fusion rate was 95.9%. All conservatively
treated type 1 and type 3 patients achieved fusion. Out

Asian Spine Journalof 17 conservatively treated type 2 patients, 15 achieved
fusions but two developed nonunion; however, two nonunion patients opted not to undergo a surgery. Subgroup
analysis showed that Philadelphia brace caused nonunion
significantly in fracture displacement >3 mm comparedto Minerva brace/Halovest (100% vs. 0%, p<0.05). All
surgically treated type 1 and 2 patients achieved fusion.
Neck pain Visual Analog Scale and Neck Disability Index
were significantly improved (both, p<0.01). According toOdom’s criteria, 93.9% (46/49) of the patients achieved
satisfactory outcomes. No major complications occurred.
Mean follow-up was 12.6 months.
Conclusions: The majority of transverse fractures of C2
body can be treated conservatively. However, surgery or
rigid Minerva brace/Halovest should be considered fortype 2 transverse fractures of the C2 body with fracture
displacement >3 mm.

PS-FP-3-2

An Analysis of 49 Cases with Pedicle Fracturesof the c2 Axis: Is Surgery Necessary?
Jong-Beom Park1, Sung-Kyu Kim2
1

Department of Orthopaedic Surgery, College of Medicine, The Catholic
University of Korea, Seoul, Korea
2
Department of Orthopaedic Surgery, Chonnam National University
Hospital, Gwangju, Korea

Purpose: C2 pedicle fractures (PFs) are not an uncommon injury but have not been focused on to the extent
that dens fractures or Hangman’s fractures have been. The
pedicle in the lumbar and thoracic spine is an importantcomponent helping to maintain the stability of the spine,
similar to the cervical spine. However, to date, little information is available about the characteristics of C2 PFs that
can affect treatment and outcome. Therefore, we sought
to investigate the characteristics of C2 PFs and to propose
appropriate treatment strategies.
Methods: A total of 49 patients with C2 PFs were included
from the database of three national trauma centers of tertiary university hospitals between January 2000 and December 2017. Radiologic data and medical records wereretrospectively reviewed.
Results: Twenty-two patients (44.9%) had unilateral C2
PFs and 27 patients (55.1%) had bilateral C2 PFs. There
was no case of C2 PF alone: among the cases of unilat-

S51

eral C2 PF, 22 patients (100%) had one or more otherC2 fractures and 20 patients (90.9%) had one or two
C2 body fractures, while two patients (9.1%) had C2–3
anterior slip and two patients (9.1%) had other cervicalinjuries. Meanwhile, among the cases of bilateral C2 PF,
27 patients (100%) had two or more other C2 fractures
and all patients (100%) had one or two C2 body fractures,five patients (18.5%) had C2–3 anterior slip, one patient(3.7%) had spinal cord injury (SCI) at C2–3 and six patients (22.2%) had other cervical injuries. In unilateral C2PFs, 3 patients (13.6%) with C2–3 anterior slip or adjacentcervical spine (C1–3) injury underwent surgery and 19
patients (86.4%) were treated with conservative methods.
In bilateral C2 PFs, 3 patients (11.1%) with C2–3 anterior
slip or SCI at C2–3 underwent surgery and 24 patients(88.9%) were treated with conservative methods. One
patient with bilateral PF, C2–3 anterior slip, and C1 posterior arch fracture developed nonunion after Philadelphia
brace application.
Conclusions: Our results showed that C2 PFs do not occur
alone and are always accompanied by other associated C2
injuries. In spite of the complex fracture characteristics,
most C2 PFs can be managed with conservative treatment. However, surgical treatments should be considered
if the C2 PFs are accompanied by the C2–3 anterior slip
and adjacent cervical spine injury.

PS-FP-3-5

Direct Osteosynthesis in Hangman’S Fracture
Risks Vertebral Artery Injury
Tokumitsu Mihara, Shinji Tanishima, Chikako Takeda,
Msaki Yoshida, Hideki Nagashima
Department of Orthopedic Surgery, Faculty of Medicine, Tottori University,
Yonago Japan

Hangman’s fracture, the traumatic spondylolisthesis of
the axis, is the second most common fracture of this bone
after odontoid fracture and is defined by the bilateralseparation of the C2 vertebral body from the neural arch.
The most commonly used classification of the fracture is
Levine and Edwards classification. Fractures with 3 mmor less translation and no angulation, more than 3 mm oftranslation and angulation, 3 mm or less translation andsignificant angulation, and unilateral or bilateral facet joint

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Asian Spine J 2021;15(Supplement 1):S1-S177

dislocations are classed as type I, type II, type IIa, and type
III, respectively. There was a report that the union rates ofconservative treatment of hangman’s fractures were nearly
100% in type I, 60% in type II, 45% in type IIa, and 35%
in type III. Therefore, some patients with type II, IIa, andIII need surgery. Among the common surgical techniques,
many authors have demonstrated good outcomes with direct C2 osteosynthesis for hangman’s fractures. However,
we encountered a patient whose vertebral artery (VA) had
moved into the gap of the fracture. This condition createsa risk of VA injury if a patient undergoes direct C2 osteosynthesis using a pedicle screw. We report this case with areview of the literature.

PS-FP-3-6

Significance of the Neurological Level of Injury
as a Prognostic Predictor for Motor Complete
Cervical Spinal Cord Injury Patients
Osamu Kawano, Takeshi Maeda, Hiroaki Sakai,
Muneaki Masuda, Yuichiro Morishita, Tetsuo Hayashi,
Kensuke Kubota, Kazu Kobayakawa, Kazuya Yokota,
Hironari Kaneyama
Department of Orthopedic Surgery, Spinal Injuries Center, Fukuoka, Japan

Purpose: To investigate the usefulness of the combinationof neurological findings and magnetic resonance imaging(MRI) as a prognostic predictor in patients with motor
complete cervical spinal cord injury (CSCI) in the acutephase.
Methods: Forty-two patients with an initial diagnosis of
motor complete CSCI (adolescent idiopathic scoliosis[AIS] A, n=29; AIS B, n=13) within 72 hours after injury
were classified into the recovery group (group R) and thenon-recovery group (group N), based on the presence orabsence of motor recovery (conversion from AIS A/B toC/D) at three months after injury, respectively. The Neurological Level of Injury (NLI) at the initial diagnosis wasinvestigated and the presumptive primary injured segment of the spinal cord was inferred from MRI performedat the initial diagnosis. We investigated whether or not thedifference between the presumptive primary injured segment and the NLI exceeded one segment. The presenceof a difference between the presumptive primary injured
segment and the NLI was compared between groups R

and N.
Results: The number of cases with the differences between
the presumptive primary injured segment and the NLI
was significantly higher in group N than in group R.
Conclusions: The presence of differences between thepresumptive primary injured segment and the NLI might
be a poor improving prognostic predictor for motor
complete CSCI. The NLI may be useful for predicting therecovery potential of patients with motor complete CSCI
when combined with the MRI findings.

PS-FP-3-7

Clinical Features and Post-treatment Complications of C2 Odontoid Fractures: A Retrospective
Analysis Using a National Inpatient Databasein Japan
Akira Honda1,2, Yoichi Iizuka1, Nobuaki Michihata3,
Tokue Mieda1, Eiji Takasawa1, Sho Ishiwata1,
Hideo Yasunaga2, Hirotaka Chikuda1
1

Department of Orthopaedic Surgery, Gunma University Graduate School of
Medicine, Maebashi, Japan2
Department of Clinical Epidemiology and Health Economics, School of
Public Health, The University of Tokyo, Tokyo, Japan3
Department of Health Services Research, Graduate School of Medicine, The
University of Tokyo, Tokyo, Japan

Purpose: To examine the clinical features and post-treatment complications in patients with isolated C2 odontoid
fractures.
Methods: We extracted data for all patients who wereadmitted with C2 odontoid fractures from the JapaneseDiagnosis Procedure Combination database between July2010 and March 2017. We then compared the post- treatment complications during hospitalization according totreatment types: conservative treatment (with or without
use of halo-vest) and surgery (anterior or posterior spinal
fixation).
Results: A total of 3,167 patients (1,533 men, 1,634 women; mean age, 70 years) with isolated C2 odontoid fractures were identified, including 1,124 patients (35%) aged
≥80 years. Among the total patients, 2,476 (78%) received
conservative treatment (with halo-vest, 728; without halovest, 1,748). The remaining 691 patients (22%) underwent
surgery (anterior surgery, 129; posterior surgery, 556;
combined surgery, 6). There were no differences between

Asian Spine Journal
the conservative treatment and surgery groups in baselinecharacteristics and preexisting comorbid conditions except for age (71 vs. 69 years, p=0.042). In-hospital deathoccurred in 136 patients (4.3%). There was no significant
difference in in-hospital mortality between the two groups(overall, conservative treatment 4.6% vs. surgery 3.0%,
p=0.066; age ≥80 years, conservative treatment 7.2% vs.
surgery 5.4%, p=0.34). Use of halo-vest was not associatedwith increased mortality (with halo-vest 3.7% vs. without
halo-vest 5.0%, p=0.15).
Conclusions: The great majority of isolated odontoid fractures occurred in elderly patients. Conservative treatment
and surgery had similarly low in-hospital mortality. Use of
halo-vest was not associated with an increase in mortality.

PS-FP-3-8

Surgical Strategy as Anterior Submandibular
Retropharyngeal Odontoid Osteotomy andPosterior Occipitocervical Fusion with C1
Laminoplasty for Fixed Atlantoaxial Dislocation
Associated with Odontoid Fracture Malunion
Kuang-Ting Yeh1,2, Tien-Wu Wu1,2, Chiu-Yu Tzai1,2,
Ing-Ho Chen1,2
1

Department of Orthopedics, Hualien Tzu Chi Hospital, Hualien, Taiwan
School of Medicine, Tzu Chi University, Hualien, Taiwan

2

Odontoid fractures comprise 7% to 13% of all cervicalspine fractures. Atlantoaxial instability often does not
generally associate with spinal cord injury but only neckpain as an initially present symptom. Odontoid malunion
often leads to atlantoaxial dislocation and the non-union
rates of type-II odontoid fractures are 36%. This study isto report a case of complex odontoid fracture malunion
accompanied by atlantoaxial dislocation which wastreated with a posterior-anterior-posterior approachedsurgical strategy. A 37-year-old male was admitted due
to progressive symptoms with a stiff limp and unsteady
gait. Preoperative examination, diagnostic radiography,
computed tomography, and magnetic resonance imaging
were performed following admission. The examinations
showed odontoid fracture malunion, an old right axial
zygapophyseal fracture, atlantoaxial dislocation, and spinal cord injury. Anterior submandibular retropharyngeal
odontoid osteotomy and posterior atlantoaxial fusion with

S53

C1 laminoplasty were then performed. A good reductionof the atlantoaxial dislocation was gained. The cervicalspinal cord compression was significantly relieved andneurological function was also significantly improved.
Anterior submandibular retropharyngeal odontoid osteotomy and posterior atlantoaxial fusion fixation is aneffective surgical strategy for treating odontoid fracture
malunion associated with odontoid fracture malunion
and it may avoid the adverse effects of the anterior transoral odontoid osteotomy.

PS-FP-3-9Anterior C2–3 Fusion Surgery Alone forHighly Displaced Hangman's Fracture with
Severe Angulation of C2–3 of More Than 30°
Jong-Beom Park1, Hyoung-Yeon Seo2
1

Department of Orthopaedic Surgery, College of Medicine, The Catholic
University of Korea, Seoul, Korea
2
Chonnam National University Medical School and Hospital, Gwangju,
Korea

Purpose: Highly displaced Hangman’s fracture is a veryrare and extremely unstable fracture of the C2 axis. Combined anteroposterior or posterior long-segment fusion
surgery is typically performed for the treatment of highly
displaced Hangman’s fracture. However, these kinds ofsurgeries increase the risk of complications, loss of motion, and hospital costs. We sought to investigate thesurgical outcomes of anterior C2–3 fusion surgery alone
for highly displaced Hangman’s fractures with severe angulation of C2–3 by more than 30° and discoligamentous
injury.
Methods: A total of five patients (four men and one woman) were included in this study with a mean age of 40.4
years (range, 26–70 years). The mean follow-up period
after surgery was 37.2 months (range, 12–96 months). The
fracture characteristics, treatment methods, and outcomes
were retrospectively analyzed.
Results: All five patients had type II Hangman’s fractures(according to the Levine and Edwards classification
scheme). None of the included patients had neurologic
deficit or other spine injury but all patients had complete
C2–3 discoligamentous injury. Before surgery, all patients
successfully achieved closed reduction by skull traction,
followed by C2–3 anterior decompression and fusion with

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Asian Spine J 2021;15(Supplement 1):S1-S177

plating. For interbody grafting, three patients received
a polyetheretherketone cage filled with an autogenous
cancellous iliac bone graft and two received autogenous
tricortical iliac bone grafts. Severe angulation (39.2° vs.
3.0°, p<0.001) and severe displacement (76.1% vs. 4.0%,
p<0.001) of C2–3 were both significantly corrected after
surgery. All patients had achieved solid fusion at last follow-up. In terms of clinical outcomes, the mean neck pain
visual analog scale score was significantly improved (8.6
points vs. 1.8 points, p<0.001). The mean neck disability
index value was also significantly improved (45.4 points
vs. 13.0 points, p<0.01). According to Odom’s criteria, allpatients achieved satisfactory outcomes. No major complications occurred. One patient complained of dysphagia,
but recovered after three months with conservative treatment.
Conclusions: Preoperative closed reduction and anteriorC2–3 fusion surgery alone should be considered as a lessinvasive and useful surgical option for highly displaced
Hangman’s fracture with severe angulation of C2–3, which
is an extremely unstable fracture of the C2 axis.

PS-FP-3-10

Is Only Anterior Stabilization Enough in Three
Column Injuries of Sub-axial Cervical Spine?:
A Long-Term Retrospective Analysis of 78
Patients
Manojkumar Basavareddy Gaddikeri, Sudhir K. Srivastava,
Aditya Raj, Sunil Bhosale
Department of Orthopaedics, SETH GS Medical College and KEM
Hospital, Mumbai, India

Study Design: Retrospective study.
Purpose: To retrospectively evaluate the long-term outcome of anterior only stabilization in three column injuries of sub axial cervical spine.
Overview of Literature: Sub-axial region of the cervicalspine accounts for about 65% of all cervical spine injuries. Three column injuries (AO type C) are high energy
injuries with unstable fracture patterns with need proper
reduction and stable fixation. A high incidence of neurological deficits is associated with these injuries. There is
no standard protocol regarding the management of suchinjuries. Reduction and fixation can be done by either

anterior, posterior, and combined approaches with eachhaving its own advantages and disadvantages.
Methods: Seventy-eight patients of three column injuries operated by anterior approach with follow-up of atleast 2 years were included and retrospectively analyzed.
Clinical data regarding age, sex, time to surgery, diagnosis, methods of reduction, postoperative mobilization,and neurological evaluation using the American Spinal
Injury Association scale (ASIA) was used. Radiological
data included pre- and post-reduction X-ray, computed
tomography, and magnetic resonance imaging. X-rays at 1,
3, 6 months,1 year, and 2 years postoperative were taken.
Parameters like classification of fracture (AO type), alignment, kyphosis angle, time, and grade of fusion mass wereassessed.
Results: Of 78 patients, 61 bifacetal and 17 unifacetal
dislocations. The most common site was C5–6 followedby C3–4 and C6–7. The mean patient age was 35.98 years
with 60 male and 18 female patients. The mean operative time is 4.4 days. Forty dislocations were reduced by
the closed method and 38 by the open anterior approach.
Fifty-six percent of patients had traumatic disc injury on
magnetic resonance imaging. All managed by single-level
anterior cervical discectomy and fusion with iliac crest
autograft for fusion. Mean preoperative lordosis was 4.44°(range, -13.4° to 25°), and mean postoperative lordosis
was 28.57° (p<0.0001). The mean loss of alignment was
2.59° by 2 years. 100% fusion was with a mean time of
22.82 weeks. Neurological recovery was in 34.6% with atleast one-grade ASIA scale. No neurological worsening orneed for revision surgery was required.
Conclusions: The goals of management in any cervicalinjury are reduction of dislocations, maintenance of alignment, cord and root decompression, bony stabilization,and fusion using an approach that is least morbid withgood long-term outcome. Above study proves that justanterior stabilization after reduction of three column injuries will suffice with a very good long-term satisfactory
outcome thereby obviating the need for global fusion.

Asian Spine Journal
PS-FP-3-11

Efficiency of Long Lateral Mass Screw
Seiya Watanabe, Kazuo Nakanishi
Kawasaki Medical School, Kurashiki, Japan

Purpose: It is necessary for patients who have instability in the cervical spine to fix. However, the lateral mass
screw is weakly fixed to the elderly with osteoporosis, andpostoperative aversion is a problem. Although the pedicle
screw has a good fixation, nerve damage, and puncture of
the vertebral artery. In recent years, advances in implants
have led to the development of screws with large swing
heads. Therefore, we report the efficiency of a long lateralmass screw.
Methods: The insertion point and insertion path that lateral mass screw can hit the longest were measured fromthe 3rd cervical vertebra to the 6th cervical vertebra using
Zed Spine manufactured by Lexi.
Results: The average screw length is 25.2 mm on the right(range, 20 to 28 mm), 24.8 mm on the left (range, 20 to 28mm), the insertion point is 2.45 mm on the head side and2.87 mm on the inside from interlaminar V, and the insertion angle is toward the head side. It was 49.6° and 30.6°
outward.
Conclusions: The insertion point of the long lateral mass
screw is 2 mm head side and 2 mm inside from interlaminar V, and the insertion angle is tilted 50° to the head sideand 30° to the outside.

PS-FP-3-12

Role of Riluzole in Acute Traumatic Cervical
Spinal Cord Injury with Incomplete Neurological
Deficit: A Prospective, Randomized Control
Study
Guna K. Pratheep, Vibhu Krishnan Viswanathan,Rajasekaran Shanmuganathan, Ajoy Prasad Shetty,
Rishi Mugesh Kanna
Department of Spine surgery, Department of Orthopaedics, Ganga medical
Centre and Hospital, Coimbatore, India

Purpose: Riluzole has been investigated extensively for its
properties of hindering the secondary injury cascade in

S55

spinal cord injury patients. Though experimental animalstudies are satisfactory, the role of Riluzole in the clinicalsetting is not clear. The aim of our study was to assess theeffect of Riluzole on the neurological (motor and sensory)
improvement in acute cervical spinal cord trauma withincomplete neurological injury.
Methods: A prospective, randomized, single-blind, placebo-controlled study was done at our center in patientswith acute cervical spinal cord injury with incomplete
neurological injury. The study population included patients with SCI presenting within 72 hours of injury, level
C3–C8, incomplete injury (International Standards for
Neurological Classification of Spinal Cord Injury [ISNCSCI] grade B, C, D), and age between 18–65 years. Patientswith penetrating injury, significant head/chest/abdominal
injury, pre-existing renal/liver disease, concomitant useof other drugs, and pregnancy are excluded. Forty-threepatients were randomized into two groups (cases andcontrols). Patients in the case group received a loadingdose (100 mg twice daily) of Riluzole started within 72
hours of injury, followed by 50 mg twice daily for the next
13 days. The control group received a placebo treatment.
All patients underwent surgery for decompression andstabilization. Postoperative rehabilitation was followed.
Patients were followed up at 6 weeks, 3 months, 6 months,
and 1 year. Outcomes measured were changes in ISNCSCI
grade at 12 months, Spinal Cord Independence Measure(SCIM 3) at 12 months, 36-item Short Form Health Survey (health-related quality of life), and Numerical Pain
Rating Scale (NPRS).
Results: Among the 43 patients, 23 were randomized in
the case group and 20 in the control group. At 1 year, there
were 18 and 16 patients in each group and the remaining
were dead or lost to follow-up. The mean age in the caseand control was 47.70±14.80 years and 51.15±14.10 years,
respectively. The mean number of levels of injury was 1.43
and 1.35 in the two groups. Mean motor score at admission in case and controls were 36.05 and 43.04 which improved to 85.06 and 91.17, respectively at 1-year followup. However, there was no significant difference (p=0.15)
in motor scores in both groups. Also, there was no statistically significant difference (p=0.394) in the sensory
scores between the two groups. SCIM and NPRS at 1-year
follow-up were also comparable (p=0.684 and p=0.061).
Conclusions: Riluzole did not significantly improve theneurological outcome in the acute traumatic spinal cord
injury patients in our study.

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Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-3-13

Traumatic Cervical Spinal Cord Injury after
Cervical Laminoplasty for Ossification of
Posterior Longitudinal Ligament
Hironari Kaneyama1, Yuichiro Morishita1,
Osamu Kawano1, Takuaki Yamamoto2, Takeshi Maeda1

ankylosed region.
Conclusions: All the five patients with traumatic CSCI had
a history of previous cervical laminoplasty for C-OPLL.
Cervical laminoplasty for C-OPLL may lead to cervicalspine with rigidity and ankylosis owning to the development of OPLL, bony facet, and laminar fusion, and may
pose a risk for traumatic CSCI with bony injury underintense external stresses on the rigid cervical spine.

1

Department of Orthopedic Surgery, Spinal Injuries Center, Fukuoka, Japan
Department of Orthopedic Surgery, Fukuoka University, Fukuoka, Japan

2

Study Design: A retrospective review of case series of fivepatients.
Purpose: To elucidate the effects of post-cervical laminoplasty on the clinical pathophysiology of traumatic cervical spinal cord injury (CSCI).
Overview of Literature: Cervical laminoplasty is widely
performed with good results in patients with cervical ossification of posterior longitudinal ligament (C-OPLL) andcervical spondylotic myelopathy. However, to the best of
our knowledge, no studies have thus far reported the incidence of traumatic CSCI after a previous history of cervical laminoplasty for compressive cervical myelopathy.
Methods: Five patients with traumatic CSCI following
cervical laminoplasty (four men and one woman) withan average age of 66.6 years (range, 45–76 years) were included in our study. The average duration between cervical laminoplasty and CSCI was 49.4 months (range, 7–82
months). The pathology of all five patients was C-OPLL.
The changes in cervical sagittal range of motion (ROM)and morphology of OPLL before cervical laminoplasty
and at the time of injury were radiologically evaluated.
Moreover, the mechanism of injury, level of injury, andneurological evaluations were discussed.
Results: Two patients were classified as American Spinal
Injury Association Impairment Scale (AIS) grade A, one
as grade B, one as grade C, and one as grade D at the timeof injury. After 24 months, neurological status improvedin three patients as evaluated with AIS. All the patientsdemonstrated ankylosed cervical spine owning to thedevelopment of the OPLL and spontaneous bony facet
and laminar fusion on post-cervical laminoplasty. A significant difference in cervical sagittal ROM preoperatively
and 6 months postoperatively (p=0.0065) was observed.
Three patients had cervical spine extension injury at theankylosed region. The other two had cervical spine flexion
injuries at the motion segment, caudal and adjacent to the

PS-FP-4-5

Mesh-Hold Bone Filling Container Vertebroplasty in the Treatment of Osteoporotic
Vertebral Fractures with Posterior Wall Injury:
A Study of the Clinical Efficacy and Safety
En Song1, Ji Zheng Li2, Yan Lin Li1, You Qing Huang3,
Fan Bing Li2, Xiao Feng Yuan4, Xue Song Chen5,
En Bin Wang6, Xian Guang Yang1, Yao Yu Xiang1
1

Department of Sports medicine, The First Affiliated Hospital of Kunming
Medical University, Kunming, China
2
Department of Orthopedics, First Clinical Medical College of Yunnan
University of Traditional Chinese Medicine, Kunming, China
3
Department of Pain, The Second Affiliated Hospital of Kunming Medical
University, Kunming, China
4
Department of Orthopedics, The First People’s Hospital of Kunming,
Kunming, China
5
Department of Pain, The Fourth People’s Hospital of Kunming, Kunming,
China
6
Department of Orthopedics, Baoshan Hospital of Traditional Chinese
Medicine, Shanghai, China

Purpose: This study aims to evaluate the clinical safety
and efficacies of mesh-hold bone filling container (MHFC)
vertebroplasty in the treatment of osteoporotic vertebral
fractures with posterior wall injury.
Methods: From October 2017 to July 2019, 17 patients (17vertebrae) with osteoporotic vertebral fractures with posterior wall injury were admitted in our hospital, including
six men and 11 women with an average age of 69.2 years(range, 59–85 years). The injured vertebrae were distributed as follows: T8 in one case, T9 in two cases, T10 in twocases, T11 in four cases, T12 in five cases, and L1 in threecases. All patients underwent MHFC vertebroplasty usinga unipedicular approach. After implanting the MHFC intoa space formed by bone expander dilatation, bone cement
is filled into the MHFC, a small amount of bone cement
can be infiltrated into the trabecular space through theAsian Spine Journal
mesh to form a microscopic twist lock and to strengthen
the vertebral body. Preoperative clinical and neurologic
evaluations were done. Radiological evaluations included
plain X-rays, computed tomography scans, and magnetic resonance imaging. The Visual Analog Scale (VAS),
Oswestry Disability Index (ODI), anterior height of thevertebral body, and Cobb’s angle of the injured vertebrae
were observed before operation and at 1 day, 1 month,and 6 months after the operation. Bone cement leakage
and postoperative complications were also observed. The
average follow-up period was 6 months.
Results: Operations were successfully completed in all 17
patients without pulmonary embolism and without spinal
cord or nerve root injury. The operation time was 29.6±5.1
minutes. Asymptomatic leakage into other sites was seenin 5 vertebrae (29.41%). The ODI results before operation
and at 1 day, 1 month, and 6 months after the operation
were 83.215±8.341, 28.125±8.461, 16.195±6.543, and11.311±5.670, respectively. The VAS results before operation and at 1 day, 1 month, and 6 months after the operation were 7.815±0.501, 2.115±0.511, 1.726±0.421, and1.630±0.112, respectively. There was improvement in the
Cobb angle and the anterior vertebral height in all cases.
Conclusions: MHFC vertebroplasty for treating osteoporotic vertebral fractures with posterior wall injury can relieve pain effectively and effectively prevent bone cement
leakage and reduce the incidence of bone cement leakage.
But this technique has a “long and steep” learning curve.

PS-FP-4-7

Clinical Safety Study of Photobiomodulation
Treatment of Acute Spinal Cord Injury by
Scattering Fiber
Zhuowen Liang, Tan Ding, Xueyu Hu, Xiaoshuang Zuo,
Zhe Wang
Department of Orthopedics, Xijing Hospital, Xi’an, China

Purpose: The effectiveness of photobiomodulation (PBM)
has been demonstrated mainly by percutaneous irradiation and intravascular irradiation on the treatment of
spinal cord injury (SCI), but the different treatment methods, the tissue absorption of light energy, and the scattering effect all make PBM face a series of difficulties in thetreatment of SCI (e.g., the light energy cannot directly

S57

regulate the treatment of the SCI site). The study aimed
to design a reliable and straightforward PBM method by
implanting a medical scattering fiber above the vertebral
plate. Moreover, the safety of this method was examined.
Methods: Twelve patients with acute SCI (American
Spinal Injury Association [ASIA] B) requiring decompression by laminectomy were selected. The medical
scattering fiber was implanted above the vertebral andwas continuously irradiated at 810 nm, 300 mW, 30 min/day, once per day for 7 days. The vital signs (temperature,
blood pressure, respiratory rate, heart rate, and oxygen
saturation), infection indicators (white blood cell [WBC],
neutrophil [NEUT], high-sensitivity C-reactive protein[hs-CRP], and procalcitonin [PCT]), photo-allergic reaction (Eosinophil and Basophil), coagulation function(prothrombin time [PT], activated partial thromboplastin
time [APTT], thrombin time [TT]), and neurological stability (ASIA sensory and motor scores and somatosensory
evoked potentials) were recorded to evaluate the safety of
PBM. Three months after surgery, 12 patients completed
follow-up.
Results: The temperature did not exceed 37.5℃ during
7-day consecutive irradiation. The blood pressure of all
subjects did not occur the condition requiring clinical intervention, and the blood oxygen saturation of all
PBM- treated patients was not below 95%. All patients
had higher WBC, NEUT, and hs-CRP at day 3 during
irradiation than those before surgery, and significantly
decreased at day 7. The PCT was within the normal range
before irradiation and during irradiation. The changes in
Eosinophil and Basophil that were closely associated withallergic reactions were within normal limits throughout
the course of irradiation. The coagulation function (PT,
APTT, TT) of patients were also in the normal range. The
ASIA sensory and motor scores of all subjects did notdecrease throughout the irradiation process, and somatosensory evoked potentials also did not show the reduced
amplitude. In the follow-up, a total of seven patients had
adverse events.
Conclusions: Our study concluded that direct treatment
of PBM at the site of SCI would not produce adverse effects within the appropriate irradiation parameters. Our
preliminary study might provide a new methodology forthe clinical PBM treatment of acute SCI.

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Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-4-8

A Novel Steerable Percutaneous Balloon
Kyphoplasty for Treatment of Thoracolumbar
Osteoporotic Vertebral Compression Fractures
En Song1, Ji Zheng Li2, Fan Bing Li2, Xiao Feng Yuan3,
En Bin Wang4, Yao Yu Xiang1, Xian Guang Yang1
1

Department of Sports Medicine, The First Affiliated Hospital of Kunming
Medical University, Kunming, China
2
Department of Orthopedics, First Clinical Medical College of Yunnan
University of Traditional Chinese Medicine, Kunming, China
3
Department of Orthopaedics, The First People’s Hospital of Kunming,
Kunming, China
4
Department of Orthopedics, Baoshan Hospital of Traditional Chinese
Medicine, Shanghai, China

Purpose: To explore the clinical efficacy and safety of anovel steerable percutaneous balloon kyphoplasty (S-PKP)
for treatment of thoracolumbar osteoporotic vertebral
compression fractures (OVCFs).
Methods: From April 2018 to October 2019, a total of 29
patients (32 vertebrae) with thoracolumbar OVCFs weretreated with a novel S-PKP. Including 10 men and 19
women with an average age of 73.4 years. The injured vertebrae were distributed as follows: T11 in six cases, T12 in
10 cases, L1 in eight cases, L2 in four cases, and L3 in fourcases. All patients underwent the S-PKP procedure usinga unipedicular approach. Introduced the novel steerable
curved bone expander from the puncture side, expansion and bending to the contralateral side then inserted
and inflated the curved balloon tamp. After vertebral
body reduction, the bone cement was injected into thevertebral body. Clinical efficacy of S-PKP treatment wasevaluated by kyphotic Cobb’s angle, Oswestry Disability
Index (ODI), and Visual Analog Scale (VAS) score. Bonecement leakage and postoperative complications were also
observed.
Results: The anterior vertebral body height of the fractured vertebrae, Cobb’s angle was a significant improvement between preoperative and postoperative values(p<0.05) without a spinal cord or nerve root injury. The
VAS was 8.2±0.3 at preoperative, 2.1±0.5 at postoperative,
1.8±0.3 at final follow-up; and the ODI was 86.3±2.2 atpreoperative, 32.1±2.9 at postoperative, 27.1±2.3 at final
follow-up. There was a statistically significant improvement in the VAS and ODI at the postoperative assessment
compared with the preoperative assessment (p<0.05). Asymptomatic leakage was seen in three vertebrae.

Conclusions: The novel S-PKP technology is a safe and efficient way for the treatment of thoracolumbar OVCFs.

PS-FP-4-9

Mid-Term Results of Anterior-Posterior
Simultaneous Reconstruction for Lower
Lumbar Spine Injury in the Elderly
Yu Maeda
The Department of Orthopedics, Miyoshino Hospital, Saitama, Japan

In recent years, extreme lateral interbody fusion andoblique lumbar interbody fusion procedures have been
introduced to Japan as a surgical procedure for lateral approach lumbar interbody fusion (LLIF). As an applicationof this technique, it has become possible to perform vertebral body replacement using a LLIF retractor for small
skin incision. As an implant for vertebral body replacement, the expandable X-core2 System and T2 STRATOSPHERE, which have a wide end plate covering the lateraldiameter of the vertebral body, have been widely usedin Japan for stable anterior column reconstruction using
a huge cage. We would like to describe the short-term
results, usefulness and precautions of anterior-posterior
simultaneous reconstruction performed for lower lumbar
spine injury (L2–4) at Miyoshino Hospital.

PS-FP-4-10

Comparison of Mini Open Wiltse Approachwith Conventional Posterior Approach inPatients with Single Segment UnstableThoracolumbar Fractures
Muhammad Siddique Hamid1, M. Hasnain Abbas1,
Ali Hassan Butter1, Muhammad Hanif Mian1,
M. Tariq Sohail2
1

Orthopaedic and Spine Department, Lahore General Hospital, Lahore,
Pakistan2
Doctor Hospital and Medical Centre, Lahore, Pakistan

Purpose: Unstable thoracolumbar fractures constitute
20% bulk of spine fractures. Road traffic accidents andaccidental fall from height are the main causes of such

Asian Spine Journal
injuries. Fracture dislocation injury is highly unstable involving all the three columns. Most commonly It involves
thoracolumbar junction. The goals of the treatments are
to restore mechanical stability of spine and leading toearly rehabilitation and mobilization. Choice of treatment
method is still controversial. The purpose of this study
is to find a superior approach for transpedicular screw
fixation of unstable thoracolumbar spine fractures while
using the mini-open Wiltse approach and traditional posterior approach.
Methods: The study was a randomized controlled trial. A
total number of 32 patient with unstable thoracolumbar
fracture were admitted, after dividing them randomly into
group A and group B, In half of the cases mini-open Wiltse approach and in the rest of the half posterior traditional approach was used and transpedicular screw fixation
was done at a level above and a level below the fractured
vertebrae. The whole of the procedure was done under CArm control.
Results: The mean age of patients in group A (Wiltse approach) was 36.00±9.68 years while in group B (conventional approach) was 35.56±7.96 years. In both groups,
male patients were more in number than females. The
mean procedure time in group A was 87.19±5.76, whilein group B was 120.94±20.94, respectively. The difference
was statistically significant (p<0.05). The mean blood loss
in both the groups showed a significant difference (p<0.0)
of 2.34±0.88 mL in group A and 12.38±4.09 in group B,
respectively. Results were compared in terms of operative
time, blood loss, postoperative hospital stay, infection, andVisual Analog Scale for pain. All the parameters showed astatistically significant difference in both groups.
Conclusions: In thoracolumbar fractures, 20% of patients
have neurological impairment. Stable fractures are treated
non surgically but surgery is required for unstable fractures. Mimi-open Wiltse approach described in 1968 is
considered classical approach for surgical treatment of
this injury. Our study results suggest that in patients withsingle-segment unstable fractures at thoracolumbar junction Wiltse mini-open approach is better than the traditional approach. Wiltse approach results in less blood loss
and short operative time, less pain, and a low infection
rate.

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PS-FP-4-12

Comparative Study to Evaluate Surgical
Outcomes between Direct Lateral Corpectomy
with Percutaneous Pedicle Screws andPosterior Spinal Fusion with Vertebroplasty
for Osteoporotic Thoracolumbar Vertebral
Fracture
Hirotaka Haro, Tetsuro Ohba, Koji Fujita, Kohtaroh Oda,
Nobuki Tanaka
Department of Orthopaedic Surgery, University of Yamanashi, Kofu, Japan

Purpose: Osteoporotic vertebral fracture (OVF) fails tobone union with conservative treatments in some cases,
which results in progressive collapse and/or pseudarthrosis. Various surgical treatments have been tried to thesecases, whereas complications as instrument failure and/or adjacent vertebral fracture (AVF) occur. We previously
performed posterior spinal fusion (PF) with vertebroplasty (VP) but recently performed corpectomy and expandable cage replacement (X-Core Adjustable VBR System).
The purpose of current study was to comparatively evaluate (1) surgical invasion, (2) mechanical complications
including implant failure and AVF, and (3) radiologicaland clinical outcomes 2 years after surgery between two
procedures.
Methods: A retrospective observational study with a cohort of consecutive patients with OVF with neurologicalimpairment who underwent surgery was conducted. The
inclusion criteria were applied: (1) initially treated conservatively with failure because of neurological deficits;(2) age >60 years; (3) the vertebral-fracture levels selected
were T11, T12, and L1. The exclusion criterion was patients who were not followed up for >2 years after surgery.
We performed radiological exams and statistical analyses
and examined clinical outcomes.
Results: One hundred and two patients were enrolled.
Fifty-six consecutive patients underwent PF with VP(group 1) from April 2012 to December 2015. Forty-six
consecutive patients underwent corpectomy and X-core
placement with posterior fixation with percutaneous pedicle screws (PPS, group 2) from January 2016 to January
2018. There was no significant difference in the mean age,bone mineral density (%YAM), number of fused levels per
patient, proportion of sex, current smokers, preoperative
Roland-Morris Disability Questionnaire (RDQ) score,

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Asian Spine J 2021;15(Supplement 1):S1-S177

Oswestry Disability Index (ODI) score, or neurologicalscore between groups. Estimated blood loss showed nosignificant difference between groups, whereas operatingtime in group 2 was significantly longer than that in group
1. RDQ, ODI, and neurological scores were improved
significantly compared with preoperative scores in bothgroups. Kyphotic angle (LKA) in group 2 was significantly
lower than that in group 1. LKA in AVF negative groupwas significantly lower than that in AVF positive group.
Conclusions: Anterior corpectomy and cage replacement
surgery with PPS is superior procedure for OVF to PF
with VP.

PS-FP-4-13

Treatment of Unstable Pelvic Ring Fractures(AO Type C) with Minimum Invasive SpinoPelvic Fixation
Takuya Morita, Takuya Taoka, Tomoyuki Takigawa,Yasuo Ito
Department of Orthopaedics, Kobe Red Cross Hospital, Kobe, Japan

Minimally invasive spino-pelvic fixation (MIS-SP) technique is the first line treatment for unstable pelvic ringfracture patients, in our department. Twenty-eight patients of unstable pelvic fractures with posterior verticaldisplacement treated in our department by MIS-SP wereselected for this study. The vertical pelvic posterior displacement of pre-treatment was 17.6 mm (range, 9 to 32.2mm), reduction distance by MIS-SP was 16.5 mm (range,
8.1 to 30.1 mm) and the average of vertical reduction improvement rate was 93.5%. The axial pelvic displacementof pre-treatment was 12.9 mm (range, 5 to 25.7 mm),
reduction distance was 11.3 mm (range, 3.9 to 19.6 mm)
and the average of axial reduction rate was 87.3%. This
study indicated MIS-SP was not only the minimum invasive rigid fixation method but also the excellent reduction
method for the unstable pelvic ring fractures with posterior vertical displacement. The treatment with MIS-SP is
useful for unstable pelvic fractures.

PS-FP-4-14

Surgical Treatment of Post-traumatic Kyphosis
in Thoraco-Lumbar Spine: A Retrospective
Analysis of Indications and Long-Term
Outcome of Surgery
Rohit Akshay Kavishwar, Ajoy Prasad Shetty,
S. Rajasekaran
Spine Surgery Department, Ganga Medical Center, Coimbatore, India

Purpose: Post-traumatic kyphosis (PTK) is a challenging complication following thoraco-lumbar (TL) spinal
trauma. It usually develops consequent to missed orconservatively managed AO type B2 injuries (posterior
ligamentous complex disruption), injuries to the vertebral end-plates, severe osteoporosis, pseudoarthrosis,
implant failure, or loosening. Progressive kyphosis canlead to recalcitrant symptoms including pain, progressive
deformity, and neurological deterioration. The aim of thecurrent study was to retrospectively analyze the long-term
radiological and clinical outcomes of patients who underwent surgical correction of PTK.
Methods: A retrospective analysis of the clinical andradiological data of PTK patients who presented to ourinstitute between January 2016 and August 2018 was
performed. Only surgically treated patients with at least a
2-year follow-up were included. For deformity correction,
we performed Pontes Osteotomy, Pedicle Subtraction Osteotomy (PSO), Bone Disc Bone Osteotomy (BDBO), andClosing Opening Wedge Osteotomy. Radiological evaluation of kyphosis was performed using Cobbs’ angle. The
functional outcome at the final follow-up was assessed using Oswestry Disability Index (ODI), Visual Analog Scale(VAS), and 12-item Short Form Health Survey score. The
statistical analysis was performed using the Student t-test.
Results: A total of 28 cases (male to female ratio, 2:3;
mean age, 30.3 years) with PTK treated by posterior spinal
deformity correction and instrumented fusion were included for this study. The most common presenting symptom was instability-type, axial back pain (n=22, 100%).
Patients (9.09%) presented with neurological deficits. The
mean time of presentation from initial injury was 16.5±7
weeks. The apex of kyphosis was located between T11
and L2 in all our patients. Osteotomies performed-Pontes(n=13), PSO (n=11), BDBO (n=2), and, closing opening
wedge (n=2). The mean preoperative Cobbs angle wasAsian Spine Journal
33.3°. Postoperatively, the mean correction, which wasachieved, was 23.85° (p<0.05). The mean surgical timewas 275±40 minutes, and the mean intraoperative blood
loss was 445±71 mL. The mean VAS score for back pain
improved from 7.2 to 2, and ODI scores decreased from58.1 to 24.1 at the last follow-up.
Conclusions: Symptomatic PTK is a rarely encountered,delayed complication following thoracolumbar trauma.
It usually develops at the junctional levels of TL spine
and most commonly present with axial, instability-typeback pain. Some of these patients present with significant
neurological deficit. Surgical deformity correction is asafe and effective method for treating this condition. Suchprocedures can enable the surgeons to achieve adequate
correction of the kyphosis and also provide ameliorated,
long-term functional outcome for the patients.

PS-FP-4-15

Preventive Effect on the Vertebral Collapse
Progression and Potential in Reducing the
Need for Surgery in Conservative Treatment
with Initial 2-Week Bed Rest for Osteoporotic
Vertebral Fracture
Toru Funayama1, Masaki Tatsumura2, Kengo Fujii3,
Shun Okuwaki4, Yosuke Shibao1, Fumihiko Eto1,
Katsuya Nagashima2, Kousei Miura1, Hiroshi Noguchi1,
Kosuke Sato1, Mamoru Kono1, Tomoyuki Asada1,
Hiroshi Takahashi1, Masao Koda1, Masashi Yamazaki1
1

Department of Orthopaedic Surgery, Faculty of Medicine, University ofTsukuba, Tsukuba, Japan2
Department of Orthopaedic Surgery and Sports Medicine, Tsukuba
University Hospital Mito Clinical Education and Training Center, Mito
Kyodo General Hospital, Mito, Japan3
Department of Orthopaedic Surgery, Showa General Hospital, Tokyo, Japan
4
Department of Orthopaedic Surgery, Kenpoku Medical Center Takahagi
Kyodo Hospital, Takahagi, Japan

Purpose: We have previously reported good results ofconservative treatment protocol with hospitalized 2-week
bed rest for fresh osteoporotic vertebral fractures (OVFs).
However, the benefits of this approach have not been
investigated yet. We aimed to elucidate the therapeutic effects of hospitalized 2-week bed rest in patients with fresh
OVFs.
Methods: The subjects, aged 65 years or older, were patients with fresh OVFs who could start treatment within

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2 weeks of the injury and could be observed for 6 months.
Two emergency hospitals affiliated with our department
were selected for this prospective study. All the enrolled
patients at one facility were instructed to undergo hospitalized 2-week bed rest (rest group: 67 patients), whereas
the enrolled patients at the other facility were not given
this instruction (non-rest group: 51 patients). A Jewett
rigid orthosis was used in all cases. The combined osteoporosis treatment was depended on the physician’s choice.
There was no difference between the two groups in age,bone mineral density, bone metabolism markers, and vitamin D level. In addition, the vertebral instability in Xrays, indicating the difference in vertebral collapse ratio
between loaded and unloaded positions, frequency ofpoor prognostic findings on magnetic resonance imaging,and degree of damage to the middle column on computed
tomography had no significant difference. We compared
the requirement of surgical treatment and the differencein vertebral collapse ratio between the loaded positions
at the start of treatment and 6 months later in the twogroups as an evaluation of vertebral collapse progression(Welch’s t-test, significance level p<0.05). We also compared bone union and the changes of activities of dailyliving (ADL).
Results: One patient (1.5%) in the rest group and sevenpatients (13.7%) in the non-rest group did not respondto conservative treatment and required surgery. Excluding these cases, the average degree of vertebral collapse
progression was 6% in the rest group and 21% in the nonrest group, indicating that vertebral collapse progressedsignificantly in the non-rest group. Bone union was 87%
and 78% in the rest and non-rest groups, respectively.
Moreover, there was no difference in the changes of ADL
between the two groups.
Conclusions: The present study shows that rest group had
the benefit for stabilization of the injured vertebral body.
In fresh OVFs, our conservative treatment protocol withhospitalized 2-week bed rest has a preventive effect onvertebral collapse progression and has the potential in reducing the number of patients who require surgery.

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Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-4-16

Effect of Teriparatide in Vertebroplasty with
Posterior Spinal Fusion for Osteoporotic
Thoracolumbar Vertebral Fracture
Yohei Shibuya, Kei Watanabe, Masayuki Ohashi,
Hideki Tashi, Tatsuo Makino
Division of Orthopedic Surgery, Niigata University Graduate School of
Medical and Dental Sciences, Nippon Niigata University, Niigata, Japan

Purpose: Vertebroplasty with posterior spinal fusion(VP+PSF) is widely used for osteoporotic vertebral fracture (OVF) with neurological symptoms because it is aless invasive procedure with good neurological recovery,
whereas the ability to correct kyphosis is limited. Whileprevious studies have reported that teriparatide (TPTD)
administration promotes fracture healing in OVF, theusefulness of TPTD in VP+PSF for OVF has been unclear.
The purpose of this study is to investigate the surgical outcomes of VP+PSF and clarify the impact of TPTD administration during perioperative period.
Methods: Seventy-three patients (mean age, 78 years; 18
men and 55 women) with OVF affected thoracolumbar
junction (T10–L2) who underwent VP+PSF with a minimum 1-year follow-up were included. Twenty-three patients who used TPTD for more than 3 months were classified in the TPTD group, and the other 50 patients in the
non-TPTD group. We evaluated radiological outcomes
including sagittal vertical axis (SVA), correction of local
kyphotic angle (LKA), subsequent vertebral fracture, andloosening of pedicle screws. Clinical outcomes were assessed using the JOA Back Pain Evaluation Questionnaire(JOABPEQ).
Results: There were no significant differences in age, gender, follow-up period, number of fused vertebrae, preoperative bone mineral density, LKA, SVA, and scores of the
JOABPEQ between the two groups. TPTD administration
was started more than 3 months before surgery, within 3months before surgery, within 1 week before or after surgery and at the first outpatient clinic after discharge in 2,
6, 10, and 5 cases, respectively. Mean postoperative SVA
in the TPTD and non-TPTD groups were 107 and 101
mm (p>0.05), respectively, and both groups showed anincrease after surgery. The TPTD group showed smaller
correction loss of LKA than in the non-TPTD group (3.4°vs. 6.8°, p<0.05), whereas there were no significant dif-ferences in the incidence of subsequent vertebral fracture
and loosening of pedicle screws and the efficacy rates ofall domains of the JOABPEQ between the two groups.
Conclusions: In the current study, perioperative use of
TPTD in VP+PSF for thoracolumbar OVF decreased theloss of LKA correction, while it had little effects on global
spinal alignment and clinical outcomes including the prevention of subsequent vertebral fracture. Therefore, further study is necessary to examine the appropriate timingor period for TPTD administration in order to improve
clinical outcomes.

PS-FP-4-17

Comparison of Balloon Kyphoplasty andConservative Treatment for Osteoporotic
Vertebral Fractures in Patients with Dementia
Atsushi Hasegawa1,2, Yoshiaki Kinoshita1,
Kazumasa Konishi2, Takumi Takeuchi2, Hideto Sano2,
Masahito Takahashi2, Shoichi Ichimura2,
Naobumi Hosogane2
1

Department of Orthopaedic Surgery, Seichikai Memorial Hospital, Tokyo,
Japan
2
Department of Orthopaedic Surgery, Kyorin University, School of Medicine,Tokyo, Japan

Purpose: Osteoporotic vertebral fractures (OVFs) occur inelderly people and often require hospitalization. In addition, OVFs lead to a long-term bedridden state because of
severe pain and dementia in elderly patients. We actively
recommend balloon kyphoplasty (BKP) for the treatmentof OVF in patients with dementia to enable getting out
of bed early. Therefore, we retrospectively investigatedwhether BKP is useful for preventing a bedridden stateand promoting early discharge in OVF patients with dementia.
Methods: In this study, dementia was defined as the patients’ inability to judge their own disease. All patients
had a grade of 3a or more in the Japanese criteria for the
degree of independence in activities of daily living (ADL).
The research period was from January 2018 to June 2020.
We retrospectively assessed 23 patients (eight men and 15
women) who underwent BKP and 22 patients (eight men
and 14 women) with conservative treatment for morethan 3 months. The average age was 86.3 years. The survey
outcomes included the Visual Analog Scale (VAS) score,Asian Spine Journal
ADL score, hospitalization duration, and complications.
The Mann-Whitney and chi-square tests were used, and
p<0.05 was considered to indicate a statistically significant
difference.
Results: The VAS score was significantly lower in BKP
group (1.3±1.7) than conservative treatment group(3.0±1.1) 1 month after admission (p<0.01). The BKP
group tended to improve ADL score earlier than the conservative treatment group at 3 months after admission(p=0.07). The hospitalization duration was 45.2±23.5 daysin the BKP group and 56.9±26.5 days in the conservative
treatment group, with no significant difference between
the groups. Five patients in the BKP group had an adjacent vertebral fracture. Excluding these five patients, thehospitalization duration in the remaining 18 patients in
the BKP group was 39.0±17.4 days (not significant).
Conclusions: The indication and timing of BKP in elderly
patients remain controversial. We investigated the advantages of BKP compared with conservative treatment. We
found that BKP tended to allow patients to improve ADL
early. There was no significant difference in the hospitalization duration in the conservative treatment group in
the BKP group with or without AVF.

PS-FP-4-18

Is Fusion Necessary in AO Type C Injuries of
the Thoracolumbar Spine?
Chandhan Murugan, Rishi Kanna, Ajoy Shetty,
Rajasekaran Shanmuganathan
Department of Spine Surgery, Ganga Medical Centre and Hospitals Pvt.
Ltd., Coimbatore, India

Purpose: Fusion surgeries are considered “gold standard”
in the management of AO type B and type C injuries of
the thoracolumbar spine (TLS). Over the past decade,various studies have reported comparable results of longterm stability in non-fusion surgeries with regard to AO
type B injuries. The purpose of this study was to evaluate
the long-term functional and radiological outcome inpatients undergoing non fusion surgery for AO type C
injuries of TLS.
Methods: This retrospective study included patients with
AO type C injuries of TLS with normal neurology who
underwent posterior instrumented stabilization without

S63

fusion. Radiographs were assessed for wedge angle, regional angle and sagittal index. Functional outcome wasassessed using Oswestry Disability Index (ODI). Statistical methodology followed was Wilcoxon test for paired
samples, Pearson correlation, and analysis of variance(ANOVA) test for unpaired samples.
Results: The study included 35 patients. The mean
preoperative regional kyphotic angle decreased from
19.8°±13.7° to 6.6°±11.3° immediately following surgery.
There was a statistically significant loss of correction andthe regional kyphotic angle increased to 8.7°±10.4° at 6
months (p=0.005) and to 9.21°±10.5° at the end of 2 years(p=0.003). The cumulative loss of disc space angle (2.4±50)
was significant at 2 years (p=0.002) follow-up starting 6
months (1.8°±4°, p=0.01) following surgery measured using estimated marginal means and pairwise comparisons.
The functional outcome was measured using the ODI, 80% of the patients reported a score <20% (minimal disability) while 20% had a score between 20%–40% (moderate
disability). The Pearson correlation (-0.023) ruled out asignificant relationship between functional outcome andloss of correction (p=0.898). The Pearson correlation also
ruled out any significant relationship between age andODI (p=0.17). The most frequently encountered AO typeA subtype was A3 (34%) followed by A4 (31%), A1 (20%),
A2 (8.5%), and A0 (6%). The ANOVA test did not reveal
a relationship between the AO A subtypes and the ODI
when compared between groups (p=0.37).
Conclusions: “Posterior instrumented stabilization without fusion” is a successful procedure in AO type C injuries
of TLS with normal neurological status.

PS-FP-4-19

Alteration of Global and Regional Sagittal
Alignment after Correction Surgery for Focal
Kyphosis at The Thoracolumbar Junction
Po Hao Huang, Chih Wei Chen, Ming Hsiao Hu,
Shu Hua Yang
Department of Orthopedics, National Taiwan University Hospital, Taipei,
Taiwan, ROC

Purpose: The sagittal balance correlates with health-related quality of life. We can use surgical methods to correct
local deformity. However, the reciprocal changes of theS64

Asian Spine J 2021;15(Supplement 1):S1-S177

sagittal parameters are not clear. We were interested in thealteration of global and regional sagittal alignment after
correction surgery for focal kyphosis at the thoracolumbar junction.
Methods: We reviewed the medical records of our patients, who received spine surgery for thoracolumbar
deformity correction with the lowest instrumented vertebra above L3. Preoperative and postoperative sagittal parameters, including local kyphotic angle, segmental cobb
angle, pelvic incidence (PI), pelvic tilt (PT), sacral slope(SS), lumbar lordosis (LL), main thoracic kyphosis (MTK),
and sagittal vertical axis (SVA), were measured. We alsomeasured correlation between sagittal parameters andfunctional outcome.
Results: We included thirteen patients (5 males and 8
females). There were significant changes of segmental
Cobb angle (46°±10° to 18°±7°, p=0.001), LL (-47°±14° to-35°±14°, p=0.002), MTK (18°±14° to 24°±13°, p=0.025),
SVA (6.1±5.1 cm to 3.9±4.1 cm, p=0.033), Visual Analog
Scale (VAS; 6±2 to 3±2, p=0.002), Oswestry Disability
Index (ODI; 48%±17% to 29%±17%, p=0.001), and PI–
LL (4°±18° to 16°±17°, p=0.002). There were no significant changes over PI (51°±14° to 52°±12°, p=0.937),
PT (26°±14° to 23°±11°, p=0.194), and SS (26°±12° to
28°±11°, p=0.141). Segmental cobb angle showed moderate correlation with VAS (rho=0.538, p=0.058, preoperative; rho=0.637, p=0.019, postoperative; rho=0.513,
p=0.073, postoperative difference) and ODI (rho=0.676,
p=0.011, postoperative). There was some sort of correlation between sagittal parameters and functional outcome,though was not statistically significant.
Conclusions: Corrective surgery significantly improved
the segmental kyphosis and the functional outcome. In
the meantime, the sagittal alignment got some sort of improvement. Functional outcome may correlate more withsuccessful correction of focal kyphosis than global sagittalalignment, but global sagittal alignment still had some
sort of influence.

PS-FP-4-20

The Osteoporosis-Induced Vertebral Fracture
like the Traumatic Burst Fracture (AO–B2)
Shows the Prolonged Instability and theProgress Local Kyphosis
Ryutaro Kozuma, Akihisa Yamashita
Department of Orthopaedic Surgery, Shimonoseki City Hospital,
Shimonoseki, Japan

Purpose: Spinous process fractures of adjacent vertebral
bodies are often overlooked in diagnostic imaging ofosteoporosis-induced vertebral body fractures (OVF). The
purpose of this study was to investigated that flectiondistraction type OVF with rupture of posterior elements,
including spinous process fractures, was refractory toconservative treatment and had a poor prognosis.
Methods: Twenty-nine OVF (AO classification B2) caseswith spinous process fractures of adjacent vertebral bodies(AO–B2 group: 12 males, 17 females; age, 79.2±6.66 years)
and 29 OVF patients who underwent balloon kyphoplasty
due to prolonged instability of posterior vertebral walland back pain (posterior wall injury [PWI] group: sevenmales, 22 females; age, 79.7±6.52 years) were included.
Wedging ratio (anterior wall height/posterior wall heightof fractured vertebral body in sitting lateral Xp×100%),
local kyphosis angle (angle formed by end plate of upperand lower vertebral bodies of fractured vertebral body inthe same image), lumbar spine young adult mean (YAM)
value were compared by t-test.
Results: The wedging rate was 34.0%±10.1% in the AO–
B2 group and 54.1%±18.1% in the PWI group, and AOB2 group was significantly advanced (p=0.00000268). The
local kyphosis angle was 33.0°±9.88° in the AO–B2 groupand 15.4°±10.5° in the PWI group, and the kyphosis deformation was also significantly stronger in the AO-B2
group (p=0.0000000193). The YAM value was not significantly different between the two groups (AO–B2 group:
80.9%±13.6%, PWI group: 73.0%±21.0; p=0.13).
Conclusions: OVF with spinous process fractures of adjacent vertebral bodies has a higher degree of instability
than OVF with posterior wall damage, which is generally
considered to have a poor prognosis, resulting in crushing and destruction of the vertebral body and kyphotic
deformity of the spinal column. Therefore, it should be
noted that AO–B2 type OVF has a poor prognosis. It isAsian Spine Journal
often difficult to point out posterior element damage froma simple roentgen image alone, and special care must
be taken not to overlook it. Computed tomography andmagnetic resonance imaging were considered to be usefulfor definitive diagnosis and treatment decision making
including early surgical intervention.

PS-FP-5-1

Optimizing the Brace-Weaning Criteria in
Adolescent Idiopathic Scoliosis: The Role of
Utilizing the New Sanders 7b Staging
Jason Pui Yin Cheung, Prudence Wing Hang Cheung
Department of Orthopaedics and Traumatology, The University of Hong
Kong

Purpose: There is no recommended guideline for brace
weaning in adolescent idiopathic scoliosis (AIS). Curve
progression after weaning may reach 46%. The Sanders
staging (SS) method is widely used internationally but has
yet to be acknowledged as an indicator for brace weaning.
The addition of the ulna physis may further refine SS for
optimizing brace weaning outcomes. The study aimed toinvestigate whether including the stages of ulnar physeal
closure in SS7 aids in a more accurate assessment forbrace weaning for patients with AIS.
Methods: This was a retrospective analysis of patients whoweaned brace-wear and consulted from June 2016 to December 2018. Patients who weaned brace-wear at Risser
stage ≥4, static standing body height, and arm span for atleast 6 months and ≥2-years post-menarche were included. Skeletal maturity at weaning was assessed using Sanders staging with SS7 subclassified into SS7a (all phalangeal
physes are fused and only distal radial physes are open,with narrowing of medial physeal plate of the distal ulna)
and SS7b (those with >50 % fusion of the medial growthplate of distal ulna). Weaning maturity grading and any
curve progression were analyzed using Fisher’s exact test,with Cramer’s V and Goodman and Kruskal’s tau.
Results: A total of 179 AIS patients (83.2% females) werestudied with a mean age of 14.8±1.1 years and Cobb angleof 34.6°±7.7° at weaning. The follow-up period was 3.4±1.8
years. At post-weaning 6-months, curve progression rates
for patients weaning at SS7a versus SS7b were 11.4% and
0%, respectively for <40° curves. The use of SS6, SS7a/ b,

S65

SS8 for maturity assessment at weaning strongly associated (Cramer’s V, 0.326; p=0.016) with whether the curve
progressed at post-weaning 6-months. Weaning with SS7
subclassification allowed a 10.6% reduction of error in
predicting curve progression.
Conclusions: The use of SS7a and SS7b allows accurate
maturity assessment for guiding brace weaning. Weaning
at SS7b is more appropriate without any curve progression
cases immediately post-weaning for small curves (<40°).
This makes reaching full fusion of both distal radius andulna physis (SS8) not necessary and brace weaning can beinitiated approximately 9.0 months earlier.

PS-FP-5-2

Computed Tomography Analysis of Sacropelvic
Parameters in Patients with and without L5
Spondylolysis
Joseph F. Baker1,2
1

Department of Orthopaedic Surgery, Waikato Hospital, Hamilton, New
Zealand2
Department of Surgery, University of Auckland, Auckland, New ZealandPurpose: An association of increased pelvic incidence (PI)and decreased sacral table angle (STA) with spondylolysis has been reported but no study has simultaneously
analyzed multiple sacropelvic variables to compare theirassociation. Via a retrospective analysis of computed tomography scans, we aimed to determine the associationof sagittal sacropelvic parameters with L5 spondylolysis.
Methods: CT scans obtained for assessment for major
trauma in patients aged >16 years were analyzed. Scans
were excluded if there was abnormal anatomy, previous
spine or hip/pelvis surgery, or spinal pathology including
deformity, infection, tumor, or trauma. Sacral anatomic
orientation (SAO), PI, pelvic thickness (PTH), femorosacral posterior angle (FSPA), STA, and sacral kyphosis(SK) were measured.
Results: A total of 202 scans were analyzed: 25 with L5
spondylolysis and 177 normal. SAO (43.3º vs. 51.6º), PI(61.7º vs. 49.8º), STA (95.4º vs. 101.8º), and SK (31.0º vs.
23.7º) were all significantly different between groups. After logistic regression analysis, only PI (odds ratio [OR],1.074; 95% confidence interval [CI], 1.026–1.124) andSTA (OR, 0.822; 95% CI, 0.734–0.920) remained signifi-

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Asian Spine J 2021;15(Supplement 1):S1-S177

cant predictors for the presence of spondylolysis. In the
spondylolysis group PI correlated significantly with PTH(r=-0.589), FSPA (r=0.880), and SK (r=0.576); in the normal group PI correlated significantly with FSPA (r=0.781)
and SK (r=0.728).
Conclusions: Simultaneously assessing multiple sacropelvic parameters we found that increasing PI is associatedwith L5 spondylolysis while decreasing STA, which likely
represents a chronic remodeling secondary to spondylolysis, is also associated with increased risk. Back pain in anadolescent or young adult with high PI or low STA shouldraise suspicion of possible occult spondylolysis.

PS-FP-5-4

Does the Segmental Flexibility Assessed by
Fulcrum-bending Radiograph Correlate with
Postoperative Cach Cobb Angle in Adolescent
Idiopathic Scoliosis?
Sachiko Kawasaki, Hideki Shigematsu, Masato Tanaka,
Akinori Okuda, Keisuke Masuda, Yuma Suga,
Yusuke Yamamoto, Yasuhito Tanaka
Nara Medical University, Kashihara, Japan

Study Design: Retrospective study.
Purpose: To clarify the correlation between the segmental
flexibility using fulcrum-bending (FB) methods and postoperative correction rate at each disc level in patients withadolescent idiopathic scoliosis (AIS).
Overview of Literature: The FB method is useful to evaluate the flexibility of the scoliotic curve in patients with AIS
and expect the postoperative global correction rate. We
have reported there are significant differences in the segmental fulcrum flexibility (FF) at each disc level using FB
methods in thoracic AIS. Assessment of segmental correlation between the preoperative flexibility and postoperative correction at each disc level has rarely been evaluatedto date.
Methods: Our retrospective analysis was based on preoperative FB radiographs and postoperative computed
tomography scans in 27 patients presenting with main
thoracic curve scoliosis. The apex vertebra was defined as
the “0” level, with the sequential cranial disc levels defined
as “+1 to +5” and the sequential caudal levels as “-1 to -4”.
The preoperative segmental Cobb angle was measured

on both, standing and FB radiographs. The segmental FF
was calculated as ([the segmental Cobb angle in standing
position–the segmental Cobb angle in the FB position]/
the segmental Cobb angle in standing position)×100.
Next, the postoperative segmental Cobb angle was measured on coronal view in computed tomography scans.
The segmental correction rate (CR) was calculated as ([thepreoperative segmental Cobb angle in standing position–
the postoperative segmental Cobb angle]/the preoperative
segmental Cobb angle in standing position)×100. Furthermore, the fulcrum-bending correction index (FBCI) was
calculated as: CR/FF×100. 100% of FBCI means postoperative correction was the same as preoperative correction
predicted from FB. We measured from the upper-most to
the lower-most end vertebra of the main curve.
Results: The correlation coefficient between FF and FBCI
was -0.519 (p<0.01), and it means a more rigid segment
corrected greater than predicted. Furthermore, there wasa significant difference in the FBCI among segments, withgreater correction detected at the periapical segments (-2,
-1, and +1; FBCI, 120%–160%) than predicted from the
FB radiograph.
Conclusions: The curve around the apex in thoracic AIS isrelatively rigid in preoperative radiography but is corrected greater than predicted. Understanding the distributionof segmental FFs and FBCIs will be important to achieveadequate correction of the curve in AIS, using the least
extensive fusion mass possible.

PS-FP-5-6

Postoperative Coronal Imbalance Following
Selective Thoracolumbar-Lumbar Fusion in
Lenke 5C Adolescent Idiopathic Scoliosis
Akira Matsumura1, Takashi Namikawa1, Minori Kato1,
Yusuke Hori1, Masayoshi Iwamae1, Ryosuke Yanai1,
Daichi Takahashi1, Hiroaki Nakamura2
1

Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka,Japan
2
Department of Orthopaedic Surgery, Osaka City University Graduate
School of Medicine, Osaka, Japan

Purpose: Selective thoracolumbar-lumbar fusion (SLF)
for patients with Lenke 5C adolescent idiopathic scoliosis(AIS) was a generally accepted procedure. SLF has a great
advantage to reduce mobile segments, but coronal imbal-

Asian Spine Journal
ance (CIB) or decompensation is one of the predictablecomplications. Several authors have proposed factors
related to coronal decompensation in Lenke 5C AIS: inadequate fusion level, postoperative shoulder imbalance,bone maturity, and curve flexibility. However, coronal decompensation after SLF in Lenke 5C AIS is not yet clearly
understood. The purpose of this study was (1) to evaluate
the incidence and prognosis of postoperative CIB after
SLF and (2) to find out the related factors with postoperative CIB in Lenke 5C AIS.
Methods: We conducted a single-center retrospective
review of data from 30 AIS patients with Lenke 5C with
who underwent SLF. The patient with less than minimum
2-year follow-up (FU) period was excluded. We measured
the radiographic parameters before surgery (PreO), 1
week after surgery, and at the latest follow-up (FFU). We
also assessed curve flexibility using side-bending films.
Clinical outcomes were evaluated using the Scoliosis Research Society-22 Questionnaire. CIB was considered tohave occurred if the C7PL was more than 2.0 cm lateral
to the central sacral vertical line (CSVL) (C7PL–CSVL>2.0 cm) at FU. We compared the parameters between thepatients with (CIB group) and without CIB (Coronal balanced: CB group).
Results: A total of 29 patients (mean age at surgery, 17.0
years; average FU period, 45.6 months) met our inclusion criteria. CIB was found in ten patients after surgery(34.5%), and decreased to 6.9% at FFU. A comparative
analysis between the CB and CIB groups showed thefollowing parameters were significantly different: age atsurgery (17.5/14.7 years, p=0.005), PreO C7-CSVL (-6.2/26.9 mm, p<0.001), LS curve in bending film (5.9°/11.2°,
p=0.02), and L5 tilt in bending film (-3.6°/-8.1°, p=0.02).
Clinical outcomes were comparable between the CB and
CIB group.
Conclusions: Although coronal imbalance was frequently
detected in the early postoperative period after SLF, it was
mostly corrected spontaneously. Postoperative CIB didn’t
impact clinical outcomes significantly. Relatively younger
age at surgery and less flexible lumbosacral curve may berelated factors with postoperative CIB.

S67

PS-FP-5-7

Preliminary Report of Surgical Outcomesof the Relatively Short Fusion (L2-Pelvis
Fixation) for the Adult Spinal Deformity
Patients
Akira Matsumura1, Takashi Namikawa1, Minori Kato1,
Ryosuke Yanai1, Daichi Takahashi1, Hiroaki Nakamura2
1

Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka,Japan
2
Department of Orthopaedic Surgery, Osaka City University Graduate
School of Medicine, Osaka, Japan

Purpose: The upper thoracic area or lower thoracic area
as the upper instrumented vertebra (UIV) and pelvis as
the lowest instrumented vertebra (LIV) was generally accepted in corrective surgery for patients with adult spinal
deformity (ASD). Longer spinopelvic fixation can provide
optimal spinal alignment, but may restrict ADL becauseof postoperative trunk stiffness. We performed L2-pelvis
fixation (L2-P PSF) for the ASD patients who had apex of
kyphosis in the lower lumbar area and compensative hypokyphosis in the thoracic area. The purpose of this study
is to evaluate the surgical outcomes of L2-P PSF for ASD
patients.
Methods: Ninety-six consecutive ASD patients who underwent corrective surgery at our institute were retrospectively reviewed with a minimum 1-year follow-up. We
performed L2-P PSF for 10 of the 96 patients. The mean
age at surgery was 64.3 years, and the average follow-up
period was 62.3 months. We performed interbody fusion(posterior lumbar interbody fusion or lumbar interbody
fusion) at each level, and three-column osteotomies wererequired in three patients. We measured the several radiographic parameters before surgery (PreO), 2 weeks
after surgery (PO), and at final follow-up (FFU). Clinicaloutcomes were evaluated using the Scoliosis Research Society-22 Questionnaire (SRS-22) PreO and FFU.
Results: Based upon the SRS-Schwab adult spinal deformity classification, three patients had an L coronal curve
type, and seven patients were classified as N type. Sagittal
modifier classification showed that in pelvic incidence(PI)–lumbar lordosis (LL) mismatch, all patients wereclassified ++, and in global alignment 2 were +, and 8
were ++, and in pelvic tilt (PT) 3 were +, and 7 were ++.
Revision surgery was required for a patient who showed
proximal junctional failure due to a UIV fracture. The

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Asian Spine J 2021;15(Supplement 1):S1-S177

radiographic parameters (PreO/PO/FFU) were as follows:
Cobb angles in lumbar curve: 25.9°/7.0°/9.4°, coronal vertical axis: 29.9 mm/12.7 mm/14.8 mm, thoracic kyphosis:
11.7°/23.0°/24.6°, thoracolumbar kyphosis: -4.0°/3.6°/6.6°,
PI–LL: 32.8°/3.4°/3.6°, PT: 30.5°/18.2°/20.5°, and C7
sagittal vertical axis: 118.7 mm/14.7 mm/34.9 mm. All
parameters significantly improved after surgery (p<0.005)
and didn’t show any significant loss of correction at FFU(p>0.005). A subtotal score of SRS-22 showed significant
improvement from PreO to FFU (PreO: 2.6, FFU: 4.0,
p<0.001).
Conclusions: L2-PSF can provide adequate correction for
ASD patients who have the apex of kyphosis in the lower
lumbar area and thoracic compensatory hypokyphosis
and normal thoracolumbar alignment.

PS-FP-5-10

Factors Influencing Postoperative Disc Angle
in Lenke Type 5C Adolescent Idiopathic
Scoliosis
Satoru Demura1,2, Kota Watanabe2,3, Teppei Suzuki2,4,
Toshiaki Kotani2,5, Takuya Yamamoto2,6, Koki Uno2,4,Noriaki Kawakami2,7
1

Department of Orthopaedic Surgery, Graduate School of Medical Sciences
Kanazawa University, Kanazawa, Japan
2
Japan Spinal Deformity Institute, Nagoya, Japan
3Department of Orthopaedic Surgery, Keio University, Tokyo, Japan
4
Department of Orthopaedic Surgery, National Hospital Organization, Kobe
Medical Center, Kobe, Japan
5
Department of Orthopaedic Surgery, Seirei Sakura Citizen Hospital,
Sakura, Japan
6
Department of Orthopaedic Surgery, Japanese Red Cross Kagoshima
Hospital, Kagoshima, Japan
7
Department of Orthopaedic Surgery, Ichinomiya Nishi Hospital,
Ichinomiya, Japan

Purposes: Disc wedging after selective fusion would be
increasing at the borderline between Lenke type 5C and
6C adolescent idiopathic scoliosis (AIS). The objectiveof this study was to evaluate the pre- and postoperative
distribution of distal disc wedging and to determine therelated factors influencing the disc angle below lowest instrumented vertebra (LIV) in patients with Lenke 5C AIS.
Methods: AIS patients with Lenke 5C curves underwent
selective fusion and were reviewed. In this series, L3
vertebra was selected as the LIV. The difference between

pre and postoperative distribution of disc angle at L3/4
was noted. The association between disc angle and radiographic curve characteristics were also examined.
Results: There were 89 patients with a mean age of 16.2
years. Anterior approach was performed in 47 cases andposterior in 42. Preoperative disc angle below LIV was
opening on the concave side (-2.5°±4.0°). At final follow- up, the disc angle distribution shifted to opening on
the convex side (6.5°±4.3°). Twenty-five of 89 patients(28%) showed disc wedging greater than 10°. The preoperative thoracic curve, side bending of thoracic curve,
lumbar curve magnitude, LIV-central sacral vertical line
(CSVL) distance, and the instrumented Cobb angle revealed significant factors. The disc angle of anterior group(8.0°±3.9°) was significantly greater than that of posterior group (4.8°±4.3°). In multivariate logistic regression
analysis, preoperative side bending of thoracic curve (>14°;
odds ratio, 5.5) and LIV-CSVL distance (>30 mm; odds
ratio, 10.6) were the independent risk factors.
Conclusions: In Lenke 5C curves, disc wedging greaterthan 10° occurred in 28%. A preoperative side bendingof thoracic curve more than 14° showed the risk of distal
disc wedging after selective fusion.

PS-FP-5-11

Prevalence and Risk Factors for Subjacent Disc
Wedging after Corrective Fusion Surgery inLenke Type 5C Curve Patients
Tomohiro Banno1, Yu Yamato1, Hiroki Oba2,
Tetsuro Ohba3, Tomohiko Hasegawa1, Go Yoshida1,
Hideyuki Arima1, Shin Oe1, Yuki Mihara1, Jun Takahashi2,
Hirotaka Haro3, Yukihiro Matsuyama1
1

Department of Orthopaedic Surgery, Hamamatsu University School of
Medicine, Hamamatsu, Japan2
Department of Orthopaedic Surgery, Shinshu University, Matsumoto, Japan3
Department of Orthopaedic Surgery, Yamanashi University, Kofu, Japan

Purpose: This study aimed to investigate the incidence
and risk factors of subjacent disc wedging (SDW).
Methods: Data of 59 adolescent idiopathic scoliosis patients with Lenke type 5 curves who underwent posterior
spinal fusion to L3 as the lowest instrumented vertebra(LIV) were retrospectively analyzed. The subjacent discangle (SDA) was defined as the angle between L3 (LIV)and L4. SDW was defined as the absolute value of SDA

Asian Spine Journal

S69≥10° at 2-year postoperation. The incidence of SDW wasinvestigated between non-selective and selective thoracolumbar/lumbar fusion group. In the selective group,
patients with and without SDW were compared.
Results: Among 59 patients, 11 had nonselective and48 had selective fusion. No patients in the non-selective
group showed SDW vs 13 patients in the selective group(27%) showed SDW. In the selective group, patients with
SDW showed significantly greater main thoracic (MT)curve, apical vertebral translation of the MT curve, upper instrumented vertebra tilt, LIV tilt, and SDA at 2
years postoperation, while no differences were found in
the coronal balance nor clinical outcome. Multivariate
analysis revealed preoperative T curve and SDA as predictors of SDW occurrence. T curve >30° and SDA >0° were
calculated as cutoff values based on the receiver operating
characteristic curve.
Conclusions: SDW seemed to occur as a compensation
mechanism for progressing deformity of unfused segments (thoracic curve and residual lumbar curve) tomaintain coronal alignment. Preoperative T curve >30°
and SDA >0° (LEV as L4) were determined as risk factors
for SDW occurrence.

retrospectively evaluated and compared radiographicalparameters between patients who underwent late (at least
10 years postoperation) revision surgeries and those without.
Results: Revision surgeries were performed in 10 patientswith a mean time to the revision of 22.3 years after the
initial operation due to disk degenerations of the lower
lumbar in eight patients and adding-on in two patients.
Postoperative radiological parameters before revision
surgeries or at last follow-up, including pelvic tilt, lumbar
lordosis, sagittal vertical axis, coronal balance, L3 and L4
tilt, and apical vertebral translation were 30.6°, 22.8°, 10.2mm, 33.9 mm, 15.0°, 18.4°, and 42.5 mm in patients withrevision surgeries, and 17.5°, 44.3°, 1.7 mm, 4.9 mm, 7.5°,
7.2°, and 23.1 mm in those without, respectively, with statistical differences.
Conclusions: We demonstrated factors significantly associated with a late revision surgery, including increases
in coronal off-balance, pelvic tilt, L3 and L4 tilt, and adecrease in lumbar lordosis. Maintaining a less lumbar tilt
and well-balanced sagittal and coronal alignment should
be considered for better long-term postoperative clinicaloutcomes in patients with AIS.

PS-FP-5-12

PS-FP-5-13

Global Imbalances in the Lower Lumbar Are Risk
Factors for Revision Surgeries in Postoperative
Adolescent Idiopathic Scoliosis Patients:
Clinical Analyses with a Median Follow-up of
17.4 Years

The Role of Routine Preoperative Echocardiogram in Adolescent Idiopathic Scoliosis
Patients Undergoing Deformity Corrective
Surgery

Tsunehiko Konomi1, Takashi Asazuma1, Shinjiro Kaneko2,
Yoshihide Yanai1, Toshiki Ohkubo1, Mitsuru Furukawa1,
Yoshiyuki Yato1
1

Department of Orthopaedic Surgery, Murayama Medical Center, Tokyo,
Japan
2
Department of Spine and Spinal Cord Surgery, Fujita Health University
Hospital, Toyoake, Japan

Purpose: The aim of this study is to clarify the radiological risk factors for late revision surgeries in postoperativeadolescent idiopathic scoliosis (AIS) patients with a longterm follow-up.
Methods: A total of 93 adult patients who underwent
spinal fusion surgery for the correction of scoliosis inadolescents with a minimum follow-up of 10 years wereAhmed M. A. Hassan, Siddharth Shah, Mohammed Patel
Spinal Surgery Department, Nottingham University Hospital NHS Trust,
Nottingham, UK

Purpose: Patients with adolescent idiopathic scoliosis(AIS) are often noted to have routine preoperative echocardiograms (ECHO). The prevalence of ECHO abnormalities and their impact on perioperative outcome is notclear, especially balancing against its costs. The study aims
at identifying the significance of routine preoperative
ECHO for AIS patients.
Methods: Clinical records of 295 adolescent AIS patients,>10 years age (mean age, 15.64 years), who underwent
primary posterior corrective surgery in a tertiary spinal
center, between 2015–2020, were reviewed. Patients with

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Asian Spine J 2021;15(Supplement 1):S1-S177

revision surgery, anterior correction, syndromic/neuromuscular scoliosis, and/or pre-existent known cardiac
comorbidities were excluded.
Results: A total of 139 patients (47%) had preoperative
ECHO and complete preoperative clinical examinations.
A total of 21 patients (15%) showed echocardiographic
abnormalities (11 trivial valvular abnormalities, five mild
root dilatation, three mild pericardial effusion, and two
septal defects). None of these patients showed any clinical symptoms/signs or required cardiology assessment,
and none had perioperative cardiovascular complications. Four patients (1.36%) demonstrated auscultatory
murmurs on preoperative clinical assessment, of which,
one had an abnormal ECHO finding (small pericardial
effusion). None reported any perioperative complications.
The average known cost of an echocardiogram was noted
to be £363.
Conclusions: The prevalence of Echo abnormalities inasymptomatic AIS patients is 15%. Despite such findings,
no patients required a cardiology workup and there wereno perioperative complications as a result. Routine preoperative Echocardiogram for all AIS patients may therefore
not be cost-effective.

PS-FP-5-14

The Role of Preoperative Somatosensory Evoked
Potential in Patients Undergoing Adolescent
Idiopathic Scoliosis Corrective Surgery
Ahmed M. A. Hassan, Siddharth Shah, Mohammed Patel
Spinal Surgery Department, Nottingham University Hospital NHS Trust,
Nottingham, UK

Purpose: Patients with adolescent idiopathic scoliosis(AIS) undergoing corrective surgery have routine somatosensory evoked potential (SSEP) monitoring preoperatively. The significance of this routine investigation is notclear. The study investigates the preoperative SSEP as apredictor for perioperative abnormalities.
Methods: A total of 207 patients who underwent corrective surgery for AIS (2015–2020), and had complete clinical records were included in the study. Findings of preoperative SSEP, baseline neuromonitoring after anesthetic
induction, and intraoperative neuromonitoring findings
were compared.

Results: Six of 207 patients (2.9%) had abnormalities detected in the preoperative SSEP. All six of them had normal baseline neuromonitoring. two of these six patients
had intraoperative motor evoked potential (MEP) alerts.
One improved with increasing mean arterial pressure. The
second persisted. Both had normal postoperative neurology 54/207 patients (26%) had intraoperative alerts. Of
these, 12 had abnormal SSEPs only, 38 had abnormal
MEPs only, and four had combined. Of the 12 patientswith intraoperative SSEP alerts, all had normal preoperative SSEP and baselines. Eleven patients improved after
limb repositioning and one persisted. Of the 38 only intraoperative MEP alerts, only two had preoperative SSEP
abnormalities. Four of 54 patients (7.4%) had intraoperatively abnormal both SSEP and MEP. All of them had
normal preoperative and baseline neuromonitoring.
Conclusions: Preoperative SSEP findings are not indicative of intraoperative neuromonitoring alerts. SSEP may
not be required as a routine preoperative investigation forpatients undergoing scoliosis correction for AIS.

PS-FP-5-15

Computed Tomography Study of the Relationship between Pelvic Incidence and Osseous
Contribution to Lumbar Lordosis in Children
Joseph F. Baker1,2
1

Department of Orthopaedic Surgery, Waikato Hospital, Hamilton, New
Zealand2
Department of Surgery, University of Auckland, Auckland, New ZealandPurpose: Although the relationship between pelvic incidence (PI) and segmental lordosis is well described in
adults there is little data regarding the relationship inchildren and how it may change with aging. The aim of
this study was to define the relationship between PI andsegmental vertebral body lordosis through childhood.
Methods: In 150 children aged a mean of 90 months(range, 2–185 months), computed tomography scans of
the lumbar spine and pelvis were analyzed measuring PI,
sacral table angle (STA), sacral kyphosis (SK), and segmental lordosis (SL) individually L1–L5. Children weregrouped by age: (1) 0–60 months; (2) 61–120 months; and(3) 121–185 months.
Results: The mean PI for the entire cohort was 40.4°,

Asian Spine Journal
mean SL for L1 -0.6, L2 0.0, L3 1.8, L4 4.7, and L5 11.4.
There were 40 children in group 1, 63 in group 2, and 37
in group 3. SL differed between age groups at all levels
except at L2. L1 and L2 became more kyphotic with increasing age; L3, L4, and L5 became more lordotic withincreasing age. The correlation between PI and SL at eachlevel became stronger with increasing age. Similarly, thecorrelation between PI and STA and between PI and SK
also became stronger with increasing age.
Conclusions: As children mature the relationship between
PI and segmental lordosis at each level becomes stronger
and the relationship trends towards that seen in the adult.
Future work should aim to define when the adult PI–LL
relationship is realized and adult alignment principles canbe applied.

PS-FP-5-16

Improvement of the Patient Demographics,
Radiographic Index and Surgical Invasivenessfor Mechanical Failure (PRISM) with Prevention
Procedures of Mechanical Failures in Adult
Spinal Deformity Surgery
Mitsuru Yagi, Satoshi Suzuki, Eijiro Okada, Satoshi Nori,
Osahiko Tsuji, Narihito Nagoshi, Masaya Nakamura,Morio Matsumoto, Kota Watanabe
Department of Orthopedic Surgery, Keio University School of Medicine,Tokyo, Japan

Study Design: Multicenter retrospective case series.
Purpose: The purpose of this study was to add on the indices of preventive procedure to improve the predictive
probability of PRISM (patient demographics, radiographic index and surgical invasiveness for mechanical failure).
Overview of Literature: The mechanical failure (MF) following adult spinal deformity (ASD) surgery is a serious
complication and often require revision surgery. We previously described the independent risk factors for MF (age,body mass index [BMI], bone mineral density [BMD],
frailty, lowest instrumented vertebra [LIV], pelvic tilt[PT]) from 321 ASDs and established the PRISM, which
stratifies the risk of MF from the sum of the standardized
regression coefficients of each risk. Hypothesis: Adding
the indices of preventive procedure for MF on to the existing indices of the risk stratification score (PRISM) may

S71

improve the predictive probability in ASD surgery.
Methods: A total of 136 surgically treated ASDs whoreached 2-year follow-up were included (age, 49±21 years;
88% female). We analyzed the associations between three
prevention procedures (upper instrumented vertebra+1
tethering [Th], teriparatide [TP], and multi-rod [MR])and MF by multivariate logistic regression analysis (MRA)
to evaluate the adjusted associations of each variable andto predict the likelihood of developing MF. The values forthe procedures by rounding the β regression coefficientwere added with the 6 indices of the original PRISM score(age, BMI, BMD, frailty, PT, level of LIV) to establish the
PRISM2. The discriminative ability of PRISM/PRISM2 for
MF were evaluated using the AUC curve. The Cuzick test
were performed to analyze the trend between the PRISM/
PRISM2 and MF.
Results: MF developed in 25% (34 cases). The β for Th,
TP, and MR were calculated by MRA and added to the
PRISM score to establish PRISM2 (β: Th, -2.48; TP, -2.98;
MR, -2.06). Trend analysis showed a significant trend
between the incidence of MF and PRISM/PRISM2. Diagnostic ability assessment using the receiver operating
characteristic (ROC) was superior in PRISM2 when compared with PRISM (PRISM2: area under the ROC curve[AUC], 0.94 [0.90 to 0.98]; PRISM: AUC, 0.87 [0.81 to0.93]; difference, 0.07; p<0.001).
Conclusions: We refined the PRISM for predicting MF in
ASD surgery by adding MF preventive procedures to therisk indices. The predictive probability of PRISM2 for thedevelopment of MF was excellent (AUC, 0.94). This model can predict a patient’s risk of MF and will help surgeons
adjust treatment strategies to mitigate the risk of MF.

PS-FP-5-18

The Effect of Lumbosacral Fusion on Scoliotic
Curves in Young Patients with Co-existingSpondylolysis/Spondylolisthesis: A Retrospective Cross-Sectional Study of Clinical,
Functional and Radiological Outcomes
Dilip Chand Raja Soundararajan, Ajoy Prasad Shetty,
Rishi Mugesh Kanna, Rajasekaran Shanmuganathan
Department of Spine Surgery, Ganga Hospital, Coimbatore, India

Study Design: A retrospective study.

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Asian Spine J 2021;15(Supplement 1):S1-S177

Purpose: To analyze the clinical, functional, and radiological outcomes of lumbosacral fusion in patients affected byscoliosis with lysis or/and listhesis and prognosticate thescoliotic behavior based on them.
Overview of Literature: The association of scoliosis withspondylolisthesis is well known. However, there is no
sufficient literature on the various patterns of scoliotic
curves, clinical presentation, surgical consensus, and outcomes.
Methods: A retrospective analysis was performed fromthe year 2008–2018. All patients managed with coexisting scoliosis and listhesis/lysis were included. Clinicalprofile, radiographic measurements, and functional outcomes were analyzed and compared between preoperativeand postoperative indices calculated at 2 years following
procedure. The outcomes were analyzed amongst threegroups (olisthetic-group-1, sciatic-group-2, and idiopathic-group-3).
Results: Eighteen adolescent patients were enrolled in the
study (16 females, two males). The study groups included
olisthetic (seven females), sciatic (four females), and idiopathic (seven patients: five females, two males). Mean age
was 13.85±2.41 years (group 1), 15.5±2.64 years (group2), and 22.57±9.32 years (group 3) with no significant
difference. Preoperative lumbar curve severity, coronaldecompensation, and lumbar lordosis were significantly
different between the groups. The mean preoperative
lumbar curve of 51.14°±15.49° (group 1) reduced to41.157°±18.96° following lumbosacral fusion. All except
one in this group had curve regression. The mean preoperative lumbar curve of 31°±7.78° (group 2) reduced to
16°±3.91° and increased from 36.33°±10.65° (group 3)
to 44.66°±9.97° following lumbosacral fusion. Though,all except one had level 1 satisfaction in North American
Spine Society index, sciatic group had better functional
outcomes in Scoliosis Research Society-22 scoring system.
The mean preoperative Oswestry Disability Index (ODI)
scores were 50.8%±6.8% (olisthetic group), 27.5%±9.57%(sciatic group), and 46.57%±11.42% (idiopathic group),and significant difference was noted between sciatic andother groups (p=0.016). The mean postoperative scores
were 6.57%±2.22% (olisthetic group), 1.5%±1.91% (sciatic), and 6%±3.26% (idiopathic) with significant difference between sciatic and other groups (p=0.027). Withingroups there was a significant improvement in ODI scoresin torsional and sciatic groups but not in idiopathic group(p=0.109).

Conclusions: This is largest available data on outcomes ofpatients with scoliosis co-existing with spondylolisthesis
in recent literature. Three specific patterns of scoliosis
need to be identified to prognosticate progression/regression of scoliosis following lumbosacral fusion. Radiological characteristics of each pattern have been described indetail to correctly designate the patient in to one group.
Not all patterns behave in the same way following lumbosacral fusion. Sciatic curves respond well compared tomoderate reduction in olisthetic curves whereas idiopathic curves show progression.

PS-FP-5-20

Change of Hip and Knee Joint after Surgery
for Adult Spinal Deformity and Correlation
between Those and Full Body Sagittal Parameters
Joonghyun Ahn, Yong-Chan Kim, Ki-Tack Kim,
Kee-Yong Ha, Qiang Luo, Seungnam Ko, Sung-Min Kim,
Hyungon Gwak
Department of Orthopaedic Surgery, Kyung Hee University Hospital at
Gangdong, Seoul, Korea

Purpose: This study aimed to elucidate the change of compensation of hip and knee and correlation of spinopelvic
parameters with them after deformity correction surgery
in adult spinal deformity (ASD) patients with normal or
only mild osteoarthritis on lower extremities.
Methods: A consecutive series of a total of 113 spinal deformity patients were included (23 men and 90 women; amean age, 68.5±14.5 years; minimum 1-year follow-up).
The following variables (C7 sagittal vertical axis [C7SVA],
lumbar lordosis [LL], pelvic tilt [PT], pelvic incidence–
lumbar lordosis mismatch [PI–LL], and T1 pelvic angle[T1PA]), and sacrum-femur angle [SFA] and femur-tibia
angle [FTA] were collected for evaluation of the regional
compensatory response of the hip and knee, respectively.
The Pearson correlation test was used to evaluate the correlation of postoperative changes of SFA and FTA with theother parameters.
Results: Both the preoperative SFA and FTA increased
significantly after the surgery (preoperative SFA,
149.6°±11.9°; 2 months postoperative SFA, 152.9°±11.3°;
and preoperative FTA, 155.9°±10.9°; 2 months postoperative FTA, 168.9°±8.4°; p<0.001). In addition, theseAsian Spine Journal
regional changes were maintained at 1-year postoperatively. After deformity correction, the preoperative C7SVA(15.5±5.5 cm), PT (37.1°±8.7°), and PI–LL (66.2°±29.0°)
significantly decreased to 3.6±5.1 cm, 20.3°±7.3°, and4.4°±15.5° (p<0.001), respectively. Except PT and C7SVA,
all measured parameters showed moderate correlation
with 2-month and 1-year postoperative changes in SFA,
(LL: r=0.351, r=0.325; PI–LL: r=−0.323, r=−0.325; T1PA:
r=−0.374, r=−0.364; the first r indicated the 2-month
postoperative values and the latter, 1-year postoperativevalues). PT showed strong correlation with postoperativechange of SFA (r=−0.620, r=−0.555). However, C7SVA
did not show statistically significant correlations with SFA(p=0.621/0.584; 2-month postoperative/1-year postoperative).
Conclusions: For patients who underwent deformity correction surgery with ASD and normal lower extremity or
only mild osteoarthritis, surgeons could expect improvement of compensatory change of the knee along with correction of spinopelvic parameters. However, the degree of
hip compensation improvement was relatively difficult topredict than that of the knee.

PS-FP-5-21

Comparison of 5-Year Surgical Results between
Anterior Surgery and Posterior Surgery in Type
5 Adolescent Idiopathic Scoliosis: Stratification
with Level of Upper and Lower End Vertebra
Kota Watanabe1, Takahiro Iida2, Kazuyuki Matsumoto2,
Hiroki Hayami2, Satoru Ozeki2, Mitsuru Yagi1,
Satoshi Suzuki1, Masaya Nakamura1, Morio Matsumoto1
1

Department of Orthopedic Surgery, Keio University, Tokyo, Japan
Department of Orthopedic Surgery, Dokkyo Medical University Saitama
Medical Center, Koshigaya, Japan
2

Purpose: For adolescent idiopathic scoliosis (AIS) type5
patients, anterior surgery (ASF) and posterior surgery(PSF) have been indicated, and the superiority between
these two methods is still controversial. Radiographicaland clinical results of both surgical methods were compared in type 5 AIS patients with identical upper end
vertebra (UEV) and lower end vertebra (LEV) to decrease
selection bias.
Methods: Eighty-five type5 AIS patients who underwent

S73

correction surgery with a minimum follow-up of morethan 5 years were included. Patients with UEV at T10
or T11 and LEV at L3 were selected. The radiographic
parameters and clinical results (Scoliosis Research Society-22 Questionnaire [SRS-22]) were compared between
ASF and PSF groups.
Results: All preoperative radiographic parameters weresimilar between ASF and PSF groups. The mean intraoperative blood loss of the PSF group (168 mL) was significantly smaller than the ASF group (367 mL), and themean intraoperative time was shorter in the PSF group(131 minutes) than the ASF group (262 minutes). However, the mean fused vertebrae in the ASF group was 0.6
vertebrae shorter than that of the PSF group. All radiographic parameters at 5 years were similar between ASF
and PSF groups. The postoperative SRS-22 scores werealso similar between ASF and PSF groups.
Conclusions: In patients with UEV at T10 or T11 andLEV at L3, all postoperative radiographic parameters weresimilar between the PSF and ASF groups. And the meandifference in fused vertebrae was 0.6 shorter in the ASF
group. The present study results will help in considering surgical options in the treatment of AIS Lenke type 5
curve.

PS-FP-5-25

Do Different Upper Instrumented Vertebra
Anchors Impact the Incidence of Proximal
Junctional Kyphosis in Adult Spinal Deformity
Surgery?
Ryosuke Yanai1, Akira Matsumura1, Tkashi Namikawa1,
Daichi Takahashi1, Hiroaki Nakamura2
1

Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka,Japan
2
Department of Orthopaedic Surgery, Osaka City University Graduate
School of Medicine, Osaka, Japan

Purpose: The purpose of this study was to retrospectively
compare the incidence of proximal junctional kyphosis(PJK) among the three types of the upper instrumented
vertebra (UIV) instruments: pedicle screw (PS), hooks,
and hooks combined with short-PS at UIV-1 in adult spinal deformity (ASD) surgery.
Methods: Fifty-three consecutive patients who underwent ASD surgery were retrospectively reviewed with a

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Asian Spine J 2021;15(Supplement 1):S1-S177

minimum 1-year follow-up (FU). We divided the patients
into three groups according to the UIV instruments: PSgroup (15 patients; 69.4 years; 78 months), hook group (25patients; 71.5 years; 59.0 months), and hook-sPS group(13 patients; 71 years; 17 months). PJK was defined as thepresence of a UIV or UIV±1 fracture in this study. We
measured several radiographic parameters (preoperative,
postoperative, and final follow-up [FU]). We compared
the parameters among the three groups.
Results: The incidence of PJK was calculated to 30% (6/15)
in the PS group, 24% (6/25) in the hook group, and 7%(1/13) in the hook-sPS group, respectively. There are sometendency of significant differences between the threegroups (p=0.09). Comparative analysis of the radiographic
parameters among the three groups demonstrated thatpreoperative pelvic incidence–lumbar kyphosis, pelvic tilt,
and thoracolumbar kyphosis at final FU were significantly
different (p<0.05) The changes of proximal junctional angle was not significantly different among the three groups(p=0.11).
Conclusions: Our study shows that the construct consisting of hooks at UIV and short PSs at UIV-1 may prevent
UIV fractures. This construct may match the concept ofsoft-landing for thoraco-pelvic fixation in the ASD patients. Further biomechanical study should be necessary
to clarify our results.

PS-FP-5-26

Short-Segmental Spinal Fusion for Chronic
Low Back Pain with Bone Marrow Edema
Adjacent to the Vertebral Endplate
Toshio Nakamae1, Naosuke Kamei1, Yoshinori Fujimoto2,
Kiyotaka Yamada2, Yuji Tsuchikawa1, Taiki Morisako1,
Takahiro Harada1, Toshiaki Maruyama1, Nobuo Adachi11Department of Orthopaedic Surgery, Graduate School of Biomedical and
Health Sciences, Hiroshima University, Hiroshima, Japan2
Department of Orthopaedic Surgery, JA Hiroshima General Hospital,
Hatsukaichi, Japan

Purpose: Corrective long spinal fusion is a widely accepted surgical method for the management of patients withadult spinal deformity. However, instrumented long-fusion for the treatment for elderly patients has been associated with a significant risk of complications and high costof medical care. The purpose of this study was to assess

the results of short-segmental spinal fusion specifically forbone marrow edema (BME) adjacent to the vertebral endplate in patients with chronic low back pain (LBP) withspinal deformity.
Methods: A prospective study was performed at our
hospitals, whereby we analyzed patients with spinal deformity and accompanying chronic LBP. For inclusion inthis study, the required patient age was at least 50 years
old, with a minimum LBP severity score of 40 mm on the
Visual Analog Scale (VAS). Standard conservative medical treatment was performed. We included patients withlumbar BME on magnetic resonance imaging (MRI) anda lumbar tenderness point on the BME lesion. We defined
BME as an area of high signal intensity on T2-weighed
fat-saturated MRI. Short spinal fusion was performed on
segments of BME. Clinical evaluations of VAS for LBP, theOswestry Disability Index (ODI), the radiological parameter for sagittal vertical axis (SVA), pelvic incidence (PI),lumbar lordosis (LL), and pelvic tilt (PT) were carried out.
To analyze the clinical and radiological data, we used thepaired t-test, and statistical significance was defined asp<0.05.
Results: There were 27 patients (19 men and 8 woman),with a mean age of 64.6 years (range, 51 to 78 years).
The mean VAS and ODI scores were 70.2±2.5 mm
and 48.4%±3.3% before surgery, 20.4±2.5 mm and
31.2%±3.1% 1 month after surgery, and 33.4±4.8 mm and29.3%±3.5% 12 months after surgery, respectively. The
mean VAS and ODI scores significantly improved after
surgery. The mean spinal fusion ranges were 1.3 segments.
The SVA, PI–LL, and PT scores were 60.7±10.6 mm,
20.5°±3.9°, and 23.8°± 2.0° before surgery, respectively.
These spinal alignment parameters did not change significantly after surgery. MRI showed the BME to decrease
after surgery.
Conclusions: Short-segmental spinal fusion is an effective
procedure for chronic LBP with BME and spinal deformity.

Asian Spine Journal

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PS-FP-5-28

PS-FP-5-29

Evaluation of Posterior Spinal Fusion for
Adolescent Idiopathic Scoliosis Lenke Type 5
Using EOS Radiography

Can Anatomic Reduction with Monosegmental
Fusion in High-Grade L5 Spondylolisthesis
Restore Global Spinopelvic Alignment?

Bin Xiao, Kai Yan, Yanbin Zhang, Jile Jiang, Yonggang Xing,
Bo Liu, Wei Tian

Hiroshi Moridaira, Satoshi Inami, Daisaku Takeuchi,
Haruki Ueda, Hiromichi Aoki, Takuya Iimura,
Hiroshi Taneichi

Department of Spine Surgery, Beijing Jishuitan Hospital, Peking University,
Beijing, China

Purpose: To evaluate the outcomes of adolescent idiopathic scoliosis (AIS) Lenke type 5 patients treated with
cantilever and direct vertebral derotation maneuvers via
EOS three-dimensional reconstruction.
Methods: A retrospective study was conducted focusing
on AIS Lenke type 5 patients from March 2018 to February 2019. The cantilever combined with direct vertebral
derotation maneuvers were used for deformity correction.
Various clinical and radiographic parameters preoperatively and at follow-up were compared, including angleof trunk rotation (ATR), Scoliosis Research Society-22r
score (SRS-22r), Cobb angle of lumbar curve, apical vertebral translation (AVT), thoracic kyphosis, lumbar lordosis, and apical vertebral rotation (AVR).
Results: Totally 16 consecutive cases were enrolled in
the study, with one male and 15 females. The average age
was 15.25±1.67 years old. The average follow-up period
was 15.67±3.01 months. The statistical significance wasfound in ATR (15.75°±5.92° vs. 5.13°±1.46°, p=0.002),
Cobb angle (41.25°±7.00° vs. 12.45°±5.85°, p<0.001),
AVT (4.49±1.30 cm vs. 1.15±0.65 cm, p<0.001), and AVR(20.44°±4.42° vs. 7.75°±4.62°, p<0.001) preoperatively
and at follow-up. The statistical correlations were foundbetween Cobb angle correction rate and AVT correction
rate (r=0.729, p=0.040), Cobb angle correction rate and
AVR correction rate (r=0.706, p=0.050), respectively. For
SRS-22r score, the statistical improvement was found in
self-image domain (3.53±0.72 vs. 4.40±0.37, p=0.025).
Conclusions: The vertebral rotation of AIS could be evaluated effectively by EOS Imaging. EOS Imaging could beapplied to rate the correction of AIS Lenke type 5 patientstreated with cantilever and direct vertebral derotation maneuvers. Besides, truncal incline improvement positively
correlated with Cobb angle correction in Lenke type 5C
curves.

Department of Orthopedic Surgery, Dokkyo Medical University School of
Medicine, Mibu, Japan

Purpose: In high-grade spondylolisthesis (HGS), it has
been demonstrated that the presence of a local lumbosacral deformity, L5 slippage, and lumbosacral kyphosis,
results in an abnormal sacro-pelvic orientation as well as
global sagittal imbalance of the spine. Recently, various
studies have reported the importance of distinguishing
between balanced and unbalanced pelvis in HGS, sustaining the importance of anatomic reduction in unbalanced
cases. In our institute, we conducted spondylolisthesis
reduction and monosegmental fusion for HGS. The aimof this study was to assess the improvement in the sagittal
spinopelvic alignment after surgical reduction.
Methods: Fifteen consecutive patients with HGS (female,
11; male, 4) underwent corrective surgery. Following radiographic parameters were measured: slip angle (SA),%slip, sacral slope (SS), pelvic tilt (PT), thoracic kyphosis(TK), lordosis L1–L5 (lumbar lordosis [LL]1–5), and thesagittal vertical axis (SVA). Pelvic balance was assessedfrom PT and SS, to identify patients with a balanced pelvis
or unbalanced pelvis.
Results: A mean follow-up period was 4.6 years (range,
2–10 years). An average age at surgery was 33 years. A
mean SA and %slip improved from 12.7° to -6.9° andfrom 66.5% to 11.1%, respectively. Mean preoperative SS,
PT, TK, LL1–5, and SVA were 42.9°, 28.0°, 13.7°, 66.1°,
and 34.1 mm, respectively. Mean final SS, PT, TK, LL1–5,
and SVA were 49.6°, 23.5°, 19.9°, 54.4°, and 22.5 mm, respectively. At baseline, nine patients had an unbalanced
pelvis, with six patients remaining unbalanced and three
becoming balanced postoperatively. On the other hand,
six patients with a preoperative balanced pelvis remainedbalanced at the final. Three patients had signs of a L5 root
lesion after surgery. In one of these patients, a revision
was performed with decompression of the L5 roots. Thesenerve root lesions resolved completely at the final.

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Asian Spine J 2021;15(Supplement 1):S1-S177

Conclusions: SVA in the patients with HGS was generally
maintained by following compensatory mechanisms: retroversion of the pelvis, increased LL, and decreased TK.
Such non-physiological postures and unbalanced pelvis
worsened patient’s quality of life. Surgical reduction in
HGS allowed to restore spinopelvic alignment that means
decrease PT, LL1–5, and increase TK. Moreover, anatomic
reduction is effective in maintaining and restoring a normal pelvic balance postoperatively. We believe that nearlycomplete reduction is essential for normalization of global
spinopelvic alignment for HGS.

PS-FP-5-31

Fat Infiltration in Back Muscles and Gluteus
Maximus Muscle Is Significantly Related to
Deterioration of Spino-Pelvic Sagittal Balance
During Gait
Kousei Miura1, Tomoyuki Asada1, Hideki Kadone2,
Kosuke Sato1, Mamoru Kono1, Fumihiko Eto1,
Yosuke Shibao1, Kentaro Mataki1, Hiroshi Noguchi1,
Hiroshi Takahashi1, Toru Funayama1, Masao Koda1,
Masashi Yamazaki1
1

Department of Orthopaedic Surgery, Faculty of Medicine, University ofTsukuba, Tsukuba, Japan
2
Center for Innovative Medicine and Engineering, University of Tsukuba
Hospital, Tsukuba, Japan

Purpose: Adult spinal deformity (ASD) patients often
present with deteriorating posture during walking, suggesting that the pathology of ASD includes dynamic factor. Although full-spine lateral standing radiograph is
widely used, it may be insufficient to evaluate ASD whenused alone. We evaluated change in dynamic spino-pelvic
balance in ASD by using three-dimensional motion analysis system (3DMAS). Additionally, we hypothesized thatfatty degeneration of trunk and hip muscles might affectchange in spino-pelvic sagittal balance during gait. We
aimed to clarify the relationship between change in spinopelvic sagittal balance during gait and fat degeneration intrunk and hip muscles in ASD.
Methods: We analyzed dynamic spino-pelvic balance during gait in 27 ASD patients by using 3DMAS (VICON).
The mean radiologic parameters were as follows: C7 sagittal vertical axis, 118 mm; thoracic kyphosis, 20°; lumbar
lordosis, 8.4°; pelvic tilt, 33°; and pelvic incidence, 48°. We

calculated dynamic thoracic, lumbar, and pelvic sagittalbalance parameters (thoracosacral angle [TSA], lumbosacral angle [LSA], and pelvic sacral angle [PSA]). The patients were asked to continue walking for as long as possible, and dynamic parameters were evaluated using datafrom initial and final lap. We also analyzed fat infiltration
rate (FI) of psoas major muscle (PM), back muscles (BM),and gluteus maximus muscles (GM) using computed tomography scan at L3 level of each patient. The correlation
between the FI of each muscle and the change in dynamic
spino-pelvic sagittal balance was investigated by theSpearman rank correlation test.
Results: The mean of the dynamic spino-pelvic sagittalbalance (initial/final) were as follows: TSA, 27.3°/31.1°;
LSA, 6.72°/8.85°; and PSA, 2.81°/4.37°. As a result, spinal
kyphosis and pelvic anteversion significantly increased
during gait. The mean FI was as follows: PM, 5.6%; BM,
11.8%; and GM, 8.3%. The deterioration of lumbar sagittal balance positively correlated with fatty degeneration of
BM (r=0.39), and the deterioration of pelvic sagittal balance positively correlated with fatty degeneration of BM(r=0.67) and GM (r=0.49).
Conclusions: Full-spine lateral standing radiograph is influenced by transient compensation for spinal deformity
and has the possibility to underestimate spinal balance
during gait. The 3D gait analysis demonstrated that spinal
kyphosis and pelvic anteversion significantly increased
while walking and could detect failure of compensationof ASD. Although 3D gait analysis could be optimal for
quantitatively evaluating spino-pelivc balance, the 3D
motion analysis system has a high initial cost. The current analysis revealed evaluation of the fatty degenerationin BM and GM has the potential to reflect the dynamicchange in spino-pelvic sagittal balance in ASD.

Asian Spine Journal
PS-FP-5-32

Single Level Posterior Lumbar Interbody Fusion
Can Improve Global Sagittal Alignment in a
Patient with Severe Dysplastic Spondylolisthesis
Kazuki Takeda1,2, Eijiro Okada2, Satoshi Suzuki2,
Satoshi Nori2, Osahiko Tsuji2, Narihito Nagoshi2,
Mitsuru Yagi2, Nobuyuki Fujita3, Masaya Nakamura2,
Morio Matsumoto2, Kota Watanabe2
1

Department of Orthopaedic Surgery, Japanese Red Cross Shizuoka
Hospital, Shizuoka, Japan2
Department of Orthopaedic Surgery, Keio University School of Medicine,Tokyo, Japan3
Department of Orthopaedic Surgery, Fujita Health University, Toyoake,Japan

Purpose: We investigated the impact of the correction of% slip and lumbosacral kyphosis by single-level posterior
lumbar interbody fusion (PLIF) on global sagittal alignment in the patients with L5–S1 severe dysplastic spondylolisthesis (DS).
Methods: A total of 22 consecutive patients (mean age,
17±11 years; mean follow-up period, 5±3 years) who underwent single-level PLIF for L5–S1 severe DS were retrospectively reviewed. The preoperative and final follow-up% slip, lumbosacral angle (LSA), dysplastic LSA (D-LSA),
sacral slope, lumbar lordosis (LL), pelvic tilt (PT), pelvic
incidence (PI), PI–LL, sagittal vertical axis, and thoracic
kyphosis were evaluated based on standing whole spine
radiographs.
Results: Although asymptomatic implant failure andmotor weakness of L5 nerve root were found in 23%(pedicle screw/rod breakage, 3 cases; pedicle screw loosening, 2 cases) and 9%, bone union was achieved, andmotor weakness was full recovered in all patients at final
follow-up. The mean preoperative % slip (59%±13%) was
significantly improved to 25%±14% (p=4.8×10-7), preoperative LSA (12°±9°) was improved to 1°±5° (p=9.5×107), and preoperative D-LSA (-1°±12°) was improved to-10°±8° (p=6.4×10-5). Moreover, the mean preoperative
LL (53°±15°), PT (28°±11°), and PI–LL (23°±20°) weresignificantly improved to 60°±8°, 25°±6°, and 13°±10° atfinal follow-up (p=0.01, 0.03, 0.003). Especially, the mean
preoperative LL, PT, and PI–LL were improved remarkably
by single-level PLIF in 11 patients who had severe sagittal
imbalance (PT >30°) (p=0.002, 1.6×10-5, 6.9×10-4).

S77

Conclusions: Single-level PLIF for L5–S1 DS showed preferable correction of slippage and lumbosacral kyphosis.
The correction of slippage and lumbosacral kyphosis improved the global sagittal alignment, particularly lumbar
lordosis, and retroverted pelvis. The maximum reduction
may lead to better local and global alignment in patientswith DS.

PS-FP-5-38

Comparison of Radiographic Outcomes
between Traditional Growing Rod and Shilla
Graduates by a Single Surgeon
Teppei Suzuki1, Koki Uno1, Masaaki Ito1,
Kenichiro Kakutani2
1

Department of Orthopaedic Surgery, National Hospital Organization Kobe
Medical Center, Kobe, Japan2
Department of Orthopaedic Surgery, Kobe University Graduate School of
Medicine, Kobe, Japan

Purpose: There is no study comparing the traditional
growing rod (TGR) graduates to Shilla growth guidancesystem (SGGS) graduates who were operated by a single
surgeon. This is a retrospective comparative cohort study.
Methods: Since 1993, a total of 96 consecutive patients
who had TGR or SGGS procedure by a single surgeon
were analyzed. There were 29 TGR graduates excluding
congenital scoliosis with rib anomalies, neurofibromatosis, and 28 patients who were SGGS graduates. There wasno significant difference between the two groups in termsof average age at initial surgery (TGR 8.8±3.0 vs. SGGS
8.2±2.7, p=0.92) and the duration of fusionless treatment(TGR 5.3±2.9 years vs. SGGS 5.3±1.8 years, p=0.46).
Because of the consecutive series, the duration of latest
follow-up after initial TGR is longer than that of SGGS(TGR 11.6±3.0 years vs. SGGS 7.9±2.2 years, p<0.01). Radiographic evaluation over treatment. Analysis included
number and frequency of complications.
Results: There was no significant difference in termsof initial correction rate (TGR 38%±13% vs. SGGS
47%±18%, p=0.62) and initial gain of T1–S1 length (TGR
40±22 mm vs. SGGS 47±15 mm, p=0.32). The greater
correction loss at pre-definitive fusion (TGR 10%±17% vs.
SGGS 35%±31%, p<0.01) and shorter elongation of T1–
S1 length during fusionless period were shown in SGGS
group (TGR 43±12 mm vs. SGGS -7±28 mm, p<0.01). InS78

Asian Spine J 2021;15(Supplement 1):S1-S177

contrast during fusionless period, the greater gain of T1–
S1 length at the definitive fusion were shown in SGGS
group (TGR 9±31 mm vs. SGGS 47±31 mm, p<0.01).
Instrumentation related complications and other complications such as infection or malalignment during fusionless treatment were observed in 24 out of 29 TGR patients(83%), and in all SGGS patients. However, in SGGS patients, there was significant decrease in number of repetitive surgeries including unplanned additional surgeries,
compared with TGR patients (TGR 1.5±0.4 vs. SGGS
0.3±0.4, p<0.01).
Conclusions: To our knowledge, this is the first study
directly comparing between TGR and SGGS graduates
operated by a single surgeon. The SGGS allowed repetitivescheduled surgeries and the comparable correction rateand spinal growth to those of TGR.

PS-FP-5-42

Surgical Outcome of Spinal Fusion for Osteogenesis Imperfecta with Scoliosis
Masaaki Ito, Koki Uno, Teppei Suzuki
Department of Orthopaedic Surgery, National Hospital Organization Kobe
Medical Center, Kobe, Japan

Purpose: Surgery for spinal deformity in osteogenesis imperfecta (OI) is a challenge due to severe and rigid deformity with extreme bone fragility. However, surgical outcome and complications still remain unclear. In addition,
an application of the pedicle screws to the tiny and fragile
vertebrae in OI is poorly understood. The purpose of thisstudy is to evaluate the result of surgical outcome, and theaccuracy and safety of pedicle screw placement for OI.
Methods: Twenty-five patients (female 14) of OI were
included in this study. Mean age was 21±9.3 years (range,
10–49 years). Mean follow-up was 5.8±2.0 years. According to Sillence classification, the mildest form ‘type I’ was
16 patients, moderate form ‘type IV’ was one patient, andthe most severe form ‘type III’ was eight patients. Fifteen
patients were performed anterior release followed by posterior fusion; the others were performed posterior only.
Two patients couldn’t be placed any implants due to extreme bone fragility. The accuracy of pedicle screw placement was evaluated by postoperative computed tomography scan. Placed screws were divided into five groups asfollows: inside the pedicle as ‘complete’, medial or lateralperforation under 2 mm as ‘med or lat <2 mm’, and over
2 mm as ‘med or lat >2 mm’. Radiographical findings andclinical data were also examined.
Results: Scoliosis was corrected from 95.6° to 65.8° after operation (correction rate 32.5%) and 68.1° at final
follow-up. Space available for the lung was improved
76.3% to 84.9% at final follow- up. Fusion was obtained in
all patients. Of the 290 screws placed, 213 screws (73%)
were placed precisely. Although, 30 screws (10%) were
penetrated from the pedicle cortex more than 2 mm. In
particular, over 2 mm penetration rates of type III weremuch higher than that of type I and IV (27.8% vs. 3.0%).
Complications related to spinal surgery included two
transient neurological disturbances, and one of the twopatients required screw removal. Surgical site infections
were observed in two patients.
Conclusions: Pedicle screws were applicable to spinal
fusion surgery in OI. Excellent bony union and no implant dislodgement were observed. However, special careshould be taken in placing pedicle screws because of the
weakness of the pedicle cortex, which could be easily penetrated especially in Sillence type III.

PS-FP-5-44

Development of a Prediction Model for
Postoperative Lumbar Cobb Angle Following
Selective Thoracic Fusion in Patients with
Adolescent Idiopathic Scoliosis
I-Hsin Chen1, Chih-Wei Chen1, Ming-Hsiao Hu1,
Po-Liang Lai2, Shu-Hua Yang1
1

Department of Orthopedics, National Taiwan University College ofMedicine and National Taiwan University Hospital, Taipei, Taiwan
2
Department of Orthopedic Surgery, Chang Gung Memorial Hospital
Linkou Branch, Taoyuan, Taiwan

Purpose: Selective thoracic fusion (STF) for adolescentidiopathic scoliosis (AIS) aims to limit spinal fusion in
main thoracic (MT) curves while achieving spontaneous
correction and sparing more mobile segments in minor
lumbar curves (LC). Although several guidelines havebeen proposed as criteria for STF, factors related to residual Cobb angle and potential progression of unfused LC
are yet to delineate. The purpose of this study is to reveal

Asian Spine Journal
radiographic parameters related to magnitude of residual
LC after STF and to establish a model to predict postoperative lumbar Cobb angle.
Methods: A multi-center observational retrospective analysis was performed in AIS patients who underwent STF
for MT curves (Lenke type 1, 2, 3, or 4). STF was defined
as a lowest level of fusion cephalic to or at L1. Multivariate
linear regression analysis was performed to study the relationship between postoperative lumbar Cobb angle andselected radiographic variables to develop the prediction
model.
Results: Ninety patients were included in this study. Meanage at AIS surgery was 14.7±2.8 years and mean followup duration was 36.7 months. The patients were female
predominant (87.5%). Preoperative Cobb angles of MT
and thoracolumbar/lumbar curves were 51.1°±9.7° and
36.8°±8.4°, respectively. The MT and TL/L Cobb angle
ratio was 1.4±0.3 and the MT:TL/L apical vertebral translation ratio was 2.9±2.4. After STF, the correction rate of
MT curve was 62.6%±13.2% and the spontaneous correction rate of LC was 57.3%±13.5%. Residual LC were lessthan 35° in all patients after STF. And there was no revision surgery was needed during the study period. Multivariate linear regression model was established as following: postoperative lumbar Cobb angle=-3.813+0.1536(preoperative thoracolumbar/lumbar Cobb)+0.0914 (preoperative LC-bending)+0.543 (preoperative lumbosacral
takeoff angle)+0.669 (postoperative lowest instrumented
vertebra [LIV] tilt) (R2=0.77, R=0.88, p<0.0001). This
formula showed high correlation and good prediction of
postoperative lumbar Cobb angle.
Conclusions: The selected variables including preoperative
TL/L Cobb angle, preoperative LC-bending angle, preoperative lumbosacral takeoff angle and postoperative LIVtilt angle yielded a formula with high accuracy for prediction of postoperative residual Cobb angle of LC after
STF. In order to achieve an acceptable curve magnitude ofunfused LC, this study disclosed the LIV tilt as a manipulatable factor and the formula as a guideline for selecting
proper candidates of STF.

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PS-FP-5-45

Does Osteoporosis Affect the Postoperative
Course of Adult Spinal Deformity Surgery?
Kenta Kurosu, Go Yoshida, Tomohiko Hasegawa,Yu Yamato, Tomohiro Banno, Hideyuki Arima, Shin Oe,
Yuki Mihara, Hiroki Ushirozako, Tomohiro Yamada,
Koichiro Ide, Yuh Watanabe, Keiichi Nakai,
Yukihiro Matsuyama
Department of Orthopedic Surgery, Hamamatsu University School of
Medicine, Hamamatsu, Japan

Purpose: The purpose of this study was to examine the effect of osteoporosis on adult spinal deformity surgery.
Methods: Among the adult spinal deformity surgeries
from March 2010 to October 2018, 209 patients withpreoperative femoral neck T scores were included in the
study. Inclusion criteria were a 2-year follow-up, surgicalage >60 years, and upper instrumented vertebra fixed with
an iliac screw. Exclusion criteria were that Parkinson’s disease and steroid use. T score ≤-2.5 was defined as groupP, and T score >-2.5 was defined as group N. Finally, 113
patients were included in this study. Patient background(age, sex, body mass index [BMI], American Society ofAnesthesiologists grade, smoking history, alcohol history,
osteoporosis treatment history), X-ray parameters (preoperative, first standing, 1 year postoperative, 2 years postoperative), quality of life (QOL) scores (Oswestry Disability Index [ODI], Japanese Orthopaedic Association [JOA],
Scoliosis Research Society-22 Questionnaire [SRS22]),and mechanical complications (MC: proximal junctional
failure, rod fracture, fracture) were compared among two
groups.
Results: There were 26 patients in the P group and 87
patients in the N group. There was a significant difference
in BMI (P/N=20.8/22.8 kg/m2, p=0.000) and alcohol history (4%/25%, p=0.036) between the two groups. There
was no significant difference in the preoperative use ofbisphosphonate and teriparatide, but the percentage of
postoperative teriparatide use was higher in group P(65.4%/35.6%, p=0.014). There was no significant difference in spinal sagittal alignment parameters between
the two groups. There was a significant difference in ODI(36.0/26.4, p=0.037), JOA walk (45.9/59.3, p=0.043), JOA
mental (40.0/51.9, p=0.010), SRS-22 function (2.85/3.29,
p=0.010), SRS- 22 self-image (3.06/3.58, p=0.004), SRS-22

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Asian Spine J 2021;15(Supplement 1):S1-S177

subtotal (3.20/3.57, p=0.034), and SRS-22 total (3.21/3.57,
p=0.020). Mechanical complications tended to be more
frequent in the P group both at 1 and 2 years postoperatively. The percentage of MC requiring reoperation at 2
years postoperatively was significantly higher in the Pgroup (23.1%/7.9%, p=0.047).
Conclusions: Osteoporosis can cause poor postoperative
course in elderly adult spinal deformity surgery. It is necessary to pay attention to measures such as preoperative
osteoporosis therapeutic agents, postoperative healthrelated QOL and mechanical complications.

PS-FP-5-47

Predicting the Natural Course of Hemivertebra
in Early Childhood: Clinical Significance ofAnteroposterior Discordance Based on ThreeDimensional Analysis
Sam Yeol Chang1, Hyoungmin Kim1, Bong-Soon Chang1,
Choon-Ki Lee2
1

Department of Orthopedic Surgery, Seoul National University Hospital,
Seoul, Korea
2
Department of Orthopedic Surgery, Chamjoeun Hospital, Gwangju, Korea

Purpose: Previous studies have utilized the three-dimensional computed tomography (3D-CT) for the classification of congenital spinal deformities and have introduced
the concept of two types of deformity: unison and discordant anomalies. However, there have been no further
studies on the clinical significance of these discordant
deformities, especially in the identification of deformities
that will progress and require an operation. Therefore,
we conducted this retrospective study to compare theprogression of scoliosis due to single hemivertebra (HV)
during early childhood, according to the anteroposterior
discordance obtained from the 3D-CT studies.
Methods: We analyzed 97 cases of single HV with thoracolumbar scoliosis, diagnosed in children before the ageof 3 years and followed up past the age of 6 years. The segmentation of the anterior and posterior components andanteroposterior discordance of the HV were evaluated using 3D-CT images. Coronal segmental curve angle (SCA)
and balance were measured using whole spine plain radiographs.
Results: Using 3D-CT, 41 (42.3%) cases of unison HV and

56 (57.7%) discordant HV were identified. Unison HVcomprised 21 (21.6%) cases of fully segmented (FS) unison HV and 20 (20.6%) cases of semi-segmented unison
HV with corresponding anterior and posterior segmentation. The 56 cases of discordant HV were further classified into 4 different types. In the 86 patients who were
followed without operation between the ages of 3 and 6
years, the average progression of SCA was significantly
larger in FS unison HV than that in the other deformities(one-way analysis of variance, p<0.001). Ten of 86 (11.6%)
patients showed a coronal imbalance at the age of 6 years,
but the proportion of patients with coronal imbalance was
not significantly different among the deformity types.
Conclusions: Anteroposterior discordance on 3D analysis
is a useful indicator for the progression of congenital scoliosis in early childhood.

PS-FP-5-51

Which Is More Predictive Value for MechanicalComplications: Fixed Thoracolumbar Alignment
versus Dynamic Global Balance Parameter
Kwang-Ryeol Kim1, Sung-Hyun Noh2, Yoon Ha3,
Kyung-Hyun Kim4
1

Department of Neurosurgery, International Saint Mary’s Hospital, Catholic
Kwandong University, Incheon, Korea
2
Department of Neurosurgery, National Health Insurance Service Ilsan
Hospital, Goyang, Korea
3
Department of Neurosurgery, Severance Hospital, Yonsei University, Seoul,
Korea
4
Department of Neurosurgery, Gangnam Severance Hospital, Yonsei
University, Seoul, Korea

Purpose: In this study, we investigate about relationshipbetween postoperative global sagittal imbalance and occurrence of mechanical complications after adult spinal
deformity (ASD) surgery. In global sagittal balance parameters, C2-hip axis (C2HA) and T1 pelvic angle (TPA)
were analyzed.
Methods: Between January 2009 and December 2016, 199
consecutive patients with ASD underwent corrective fusion of more than 4 levels and were followed up for morethan 2 years. Immediate postoperative and postoperative
2-year whole spine X-rays were checked for evaluating
immediate postoperative C2HA, TPA, and other parameters. In clinical outcomes, back and leg pain Visual Analog

Asian Spine Journal
Scale (VAS), Scoliosis Research Society-22 Questionnaire(SRS-22), Oswestry Disability Index (ODI), 36-item ShortForm Health Survey (SF-36) were evaluated.
Results: Total of 199 patients (26 males and 173 females)
were reviewed, the average age was 66.8±12.28 years, andthey were followed for an average of 30.54±10.25 months.
Based on the occurrence of mechanical complications, acomparative analysis was performed for each parameter.
In univariable analysis, mechanical complications weresignificantly much more occurred in C2HA abnormalgroup (odds ratio [OR], 3.296; p<0.001; area under the
curve [AUC]=0.645). In multivariable analysis, the result
was much more related (OR, 2.924; p=0.001; AUC=0.727).
In contrast, there was no significant difference between
normal and the occurrence of mechanical complicationsin TPA. In clinical outcomes, the differences of SRS-22,
ODI, SF-36 physical component summary (PCS) weresignificantly improved in C2HA normal group (normal
vs. abnormal; SRS-22: 0.88±0.73 vs. 0.68±0.64, p=0.042;
ODI: -24.72±20.16 vs. -19.01±19.95, p=0.046; SF-36 PCS:
19.33±18.55 vs. 12.90±16.73, p=0.011).
Conclusions: To maintain the global balance through thecervical compensation even if the thoracolumbar global
balance is not correct. It could make reduce the prevalence of mechanical complications. The C2HA could be
useful postoperative predictable factor for occurrence of
mechanical complications.

PS-FP-5-52

Mid-Term Health-Related Quality of Life and
Its Related Factors Following Adult Spinal
Deformity Surgery: A Minimum 5-Year Followup Case Series
Masayoshi Iwamae1, Akira Matsumura2, Yusuke Hori3,
Ryosuke Yanai2, Takashi Namikawa2, Minori Kato2,
Hiroaki Nakamura3
1

Department of Orthopaedic Surgery, Nishinomiya Watanabe Hospital,
Nishinomiya, Japan2
Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka,Japan
3
Department of Orthopaedic Surgery, Osaka City University Graduate
school of Medicine, Osaka, Japan

Purpose: Several reports indicated that adult spinal deformity (ASD) surgery showed significant improvement in

S81

health-related quality of life (HRQOL) with short-term
follow-up (FU) period. However, there are still unknown
that HRQOL can be maintained with mid-term FU. The
aim of this study was to evaluate the mid-term HRQOL in
ASD surgery and to identify the factors related to HRQOL
in mid-term FU.
Methods: Study design was retrospective cohort study.
Sixty-one consecutive ASD patients who underwent spinopelvic fixation (mean fused level: 9.9 segments) at our
institute from 2010 to 2015. Four patients with additional
surgeries and two patients who could not be followed formore than 5 years were excluded in this study. We identified 55 ASD patients (mean age, 66.8 years; average FU
period, 83.0 months), and evaluated HRQOL with Scoliosis Research Society-22 Questionnaire (SRS-22) and physical component summary (PCS) and mental component
summary (MCS) of SF-36 before surgery (Preop), 2 years
after surgery (PO2Y), and at final FU. We also evaluatedthe trunk stiffness using lumber stiffness disability index(LSDI) at FU.
Results: HRQOL significantly improved PO2Y and maintained at FU (p<0.0001, p>0.5). Each domain (Preop/
PO2Y/FU) were as follows: subtotal score of SRS-22,
2.6/3.9/3.8; PCS, 21.4/35.4/34.4; and MCS, 42.1/53.2/52.2.
Key radiographic parameters (Preop/PO2W/PO2Y/FU)
were thoracic kyphosis (TK: 13.0°/26.4°/34.1°/34.3°),
pelvic incidence–lumbar lordosis (40.5°/3.2°/6.5°/6.4°),
pelvic tilt (32.5°/21.0°/23.9°/23.7°), and sagittal verticalaxis (94.9/27.1/46.3/47.5 mm). Mean LSDI was calculated to 19.1 points. Univariate analysis indicated thatPCS was significantly correlated with age at surgery (r=0.62, p=0.002), LSDI (r=-0.61, p=0.003), TK (r=-0.49,
p=0.005), and TLK (r=-0.59, p=0.004). MCS didn’t show
any significant correlation. SRS-22 showed significant
correlation with age at surgery (r=-0.36, p=0.04), LSDI
(r=-0.57, p=0.007), TK (r=-0.46, p=0.01), and TLK (r=0.53, p=0.002). Multivariate logistic analysis indicated thatsignificant related factors for PCS was age (p=0.04; 95%
CI, -0.78 to -0.028) and LSDI (p=0.02; 95% CI, -1.6 to-0.14), and for SRS-22 was LSDI (p=0.005; 95% CI, -0.08
to -0.02).
Conclusions: HRQOL after ASD surgery significantly improved and maintained in mid-term FU. Age and trunk
stiffness may be possible risk factors for HRQOL in ASD
surgery. Improving the trunk flexibility may be importantfor postoperative HRQOL in the ASD patients.

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Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-5-53

Predicting the Progression of Thoracolumbar
Kyphosis in Achondroplasia Patients after
Walking Age: Generalized Estimating Equation
Analysis
Su Jung Mok, Hyoungmin Kim, Sam Yeol Chang,
Sung Cheol Park, Bong-Soon Chang, Tae-Joon Cho,
Jung Min Ko

achondroplasia. Among various radiological parameters,
apical vertebral translation and wedge vertebral height areconsidered as the driving factors in the TLK progression,
which can be explained by the Hueter-Volkmann rule. In
addition, the presence of severely deformed vertebra rather
than the number of deformed vertebrae seems to be morecritical in the progression of TLK in achondroplasia patients.

Seoul National University Hospital, Seoul, Korea

PS-FP-5-54

Purpose: The purpose of this study is to identify the trendof changes in radiologic parameters over age and to predict the factors that ultimately affect the progression ofthoracolumbar kyphosis (TLK).
Methods: In this study, we retrospectively reviewed allachondroplasia patient who visited our institution from
July 2001 to December 2020. Among these patients, 81
patients who have TLK confirmed in simple radiographbefore age of 10 were included. Radiographic parameters
were measured on D-L spine lateral or whole spine lateralview. We divided and analyzed two groups based on the
TLK angle for patients (n=49) who had standing x-rays
after 36 months of age: the progression group (P group)
versus the resolution group (R group). The R group was
defined as a group of patients who had TLK angle lessthan 20° at the last follow-up, whereas P group had TLKof more than 20°. The two groups used the Student t-test
to compare mean value. And, for each parameter, different changes in age were predicted with a scatter plot, andgeneralized estimating equation was performed.
Results: The results of this study also showed the tendency
of TLK angle to increase until the sitting age and then decrease as patients start standing. According to age, T10–
L2 angle, Cobb’s angle, apical wedge vertebral translation,
percentage of wedge vertebral height, and the number ofanterior heights less than 30% of posterior wall differ significantly between the two groups. Parameters without significant interactions for age, percentage of wedge vertebral
width (both superior and inferior) did not differ according
to age, but the P group was 6.135% and 6.375% higher thanthe R group, respectively. The ratio of wedge vertebra thatanterior wall is less than 30% of posterior was also higher
in the P group by about 0.207, regardless of age.
Conclusions: In this study, we described the natural courses of patients with or without the progression of TLK in

Oblique Lumbar Interbody Fusion Combinedwith Anterior Screws Fixation for SurgicalTreatment of Lumbar Degenerative Scoliosis
Yutong Gu1,2
1

Department of Orthopaedic Surgery, Zhongshan Hospital Fudan University,
Shanghai, China
2
Department of Orthopaedic Surgery, Shanghai Public Health ClinicalCenter, Fudan University, Shanghai, China

Purpose: We designed oblique lumbar interbody fusion(OLIF) combined with anterior screws fixation in thesame approach for the treatment of lumbar degenerative
scoliosis in order to reduce the invasiveness and the duration of operation. The purpose of study is to evaluate thefeasibility, efficacy, and safety of this surgical method.
Methods: Eight cases of lumbar degenerative scoliosis(coronal Cobb angle >10º) underwent OLIF (using cage
and allograft bone) combined with anterior screws fixation
for L2–5 through the mini approach in a right lateral position without real-time monitoring by electromyography
in this study. We assessed statistical differences between
preoperative and postoperative (12 months) coronal andsagittal parameters. Visual Analog Scale (VAS) score andOswestry Disability Index (ODI) were evaluated before
and 12 months after surgery. The fusion rate at OLIF cage,
total blood loss, incision length, operation time, hospitalstay, and surgical complications were also evaluated.
Results: The duration of operation was 217.5±22.7 minutes. There was a mean blood loss of 110 mL (range, 50–
600 mL). The incision length was 4.6±0.4 cm. The mean
stay at the hospital was 6 days (range, 5–8 days). The average follow-up duration was 13.5 months (range, 12–18
months). At 1-year follow-up, all patients who underwent
combined OLIF and anterior screws fixation achieved statistically significant improvement in coronal Cobb angle

Asian Spine Journal(range, 22.7º±4.8º to 9.8º±3.7º), apical vertebra translation(range, 2.5±0.8 to 1.5±1.0 cm), coronal vertical axis (range,
2.2±1.6 to 0.6±0.4 cm), sagittal vertebral axis (range, 6.3[0.2–23.4] to 2.3 [0.1–9.6] cm), thoracic kyphosis (range,
25.2º±4.0º to 28.7º±4.8º), lumbar lordosis (LL) (range,
29.4º±9.5º to 37.9º±8.5º), pelvic incidence (PI) (range,
52.4º±13.1º to 49.0º±11.3º), pelvic tilt (range, 28.4º±6.9º
to 22.4º±5.7º), and PI–LL mismatch (range, 23.0º±11.4º to
11.1º±8.9º). For the clinical evaluation, VAS for back pain
(range, 8 [6–10] to 1 [0–2]) and ODI (range, 55.6±8.7
to 21.1±3.4) improved significantly after surgery. Fusion
grades based on the Bridwell grading system at 1-year
follow-up were grade I in 17 segments (70.8%) and grade
II in seven segments (29.2%). No patients had any form of
permanent iatrogenic nerve damage and a major complication. No failure of instruments was observed.
Conclusions: OLIF combined with anterior screws fixation is a good choice of minimally invasive surgery for
lumbar degenerative scoliosis.

PS-FP-5-55

Propensity Score-Matched Analysis to Assess
the Risk Factor of Postoperative Proximal
Junctional Fracture in Adult Spinal Deformity
Surgery
Junya Katayanagi, Takahiro Iida, Atsuki Hayamizu,
Kazuyuki Matsumoto, Hirokazu Furukawa,
Hiroki Konuma, Tsukasa Yanase, Tetsuya Jinno

S83

tion study comprised 78 women aged 70.7±7.5 years who
had undergone long spinal fusion (≥six segments) for
spinal deformity in our institution from 2014 to 2017 andbeen followed up for ≥2 years. We excluded patients due
to acute VFs, adult idiopathic scoliosis and Parkinson’s
disease. Pre-existing VFs were identified on preoperative
whole spine radiographs and patients grouped according
to their presence and severity by Genant classification. We
used propensity score analysis to reduce patient selection
bias of this cohort. The postoperative incidences of PJFr
and proximal junctional kyphosis/failure were assessed in
the whole cohort and after propensity score matching andcompared according to pre-existing VF status using Student t-test and Mann-Whitney tests.
Results: In the whole cohort, the incidences of PJFr andproximal junctional kyphosis/failure were significantly
greater in patients with pre-existing severe VF than nonVFs. The latter were younger, less likely to have received
teriparatide, and had smaller pelvic tilts and pelvic incidence minus lumbar lordosis than those with pre- existingVFs. After propensity matching to minimize the effects ofthese differences, we identified the incidence of PJFr was
significantly higher in the severe VF than non-VF group(adjusted odds ratio, 8.8; PJFr 15.4% vs. 61.5%; p<0.05;
95% confidence interval, 1.3–57.4).
Conclusions: Pre-existing VFs are as important osteoporosis surrogate markers as dual energy X‐ray absorptiometry, while pre-existing VFs are a risk factor for postoperative PJFr in older patients undergoing long spinal fusion
for spinal deformity.

Department of Orthopaedics, Dokkyo Medical University Saitama Medical
Center, Koshigaya, Japan

PS-FP-5-56

Purpose: Increasing numbers of older adults with spinal deformity have recently been undergoing corrective
surgery to improve their quality of life. Such surgery has
a high incidence of complications, proximal junctional
kyphosis reportedly occurring in 20%–40% of cases. We
therefore aimed to determine the incidences of postoperative proximal junctional fracture (PJFr) and proximal
junctional kyphosis/failure according to pre-existing vertebral fracture status (used as a surrogate for bone massdensity) and identify whether pre-existing vertebral fracture (VF) is a risk factor for complications after surgery
for adulthood spinal deformity.
Methods: The cohort of this retrospective single institu-

Clinical Outcomes of Extensive Corrective
Fusion Surgery from Thoracic Spine toPelvis for Adult Spinal Deformity at 5 Years
Postoperatively
Hideyuki Arima, Tomohiko Hasegawa, Yu Yamato,
Go Yoshida, Tomohiro Banno, Shin Oe, Yuki Mihara,
Hiroki Ushirozako, Tomohiro Yamada, Koichiro Ide,
Yuh Watanabe, Keiichi Nakai, Kenta Kurosu,
Yukihiro Matsuyama
Department of Orthopedic Surgery, Hamamatsu University School of
Medicine, Hamamatsu, Japan

Purpose: Patient-reported outcomes (PROs) up to 2 years

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Asian Spine J 2021;15(Supplement 1):S1-S177

after corrective surgeries for adult spinal deformity (ASD)
have been well-studied, but there are few reports of medium- to long-term results. The purpose of this study
was to investigate whether PROs were consistent from 2
to 5 years after extensive corrective fusion surgery fromthe thoracic spine to the pelvis for ASD, and to analyze
whether revision surgery affected long-term outcomes.
Methods: We retrospectively analyzed patients who underwent extensive corrective fusion surgery from the thoracic spine to the pelvis for ASD between 2010 and 2015
and who were followed up for more than 5 years. Patientswith neuromuscular disease, infection, and metastatic tumors were excluded. Radiographic parameters and PROs
(revised Scoliosis Research Society-22 [SRS-22r], Oswestry Disability Index [ODI]) preoperatively and at 2 and 5
years postoperatively were investigated, and the correlations between PROs at these time points were investigated. We compared the change in PROs at 2 years (ΔPRO2
years) and 5 years (ΔPRO5 years) after surgery. We also
compared ΔPRO2 years and ΔPRO5 years of patients who
did and did not undergo revision surgery after the index
surgery.
Results: Of 168 patients who underwent extensive corrective fusion surgery from the thoracic spine to the pelvis,
96 (mean age, 66.7 years) were analyzed. The PROs at 2
and 5 years after surgery showed significant correlations inall domains (SRS-22r function [r=0.752], pain [r=0.644],
self-image [r=0.668], mental health [r=0.719], subtotal[r=0.757], and ODI [r=0.789]). No significant differenceswere found between ΔPRO2 years and ΔPRO5 years
in the other domains, except for self-image (1.4±1.0 vs.
1.0±1.0, p=0.002) and ODI (-14±18 vs. -17±18, p=0.018).
There were no significant differences between the ΔPRO2
years and ΔPRO5 years in the presence of revision surgery
in any domain (p>0.05).
Conclusions: PROs at 2 years after corrective surgery for
ASD were strongly correlated with PROs at 5 years after
surgery. PROs were maintained or improved at 5 years
after surgery, except for the self-image domain. The presence or absence of revision surgery was not an aggravating factor in the mid- to long-term clinical outcomes ofextensive corrective fusion surgery for ASD.

PS-FP-5-59

Upper End Vertebra of Proximal Thoracic Curveat T1 is a Novel Risk Factor of Postoperative
Shoulder Imbalance in Type 2 Adolescent
Idiopathic Scoliosis
Norihiro Isogai1,2,3, Mitsuru Yagi1,3, Nao Otomo1,3,
Yoshihiro Maeda1,3, Satoshi Suzuki1,3, Satoshi Nori1,3,
Osahiko Tsuji1,3, Narihito Nagoshi1,3, Eijiro Okada1,3,
Nobuyuki Fujita3,4, Masaya Nakamura1,3,
Morio Matsumoto1,3, Kota Watanabe1,3
1

Department of Orthopaedic Surgery, Keio University School of Medicine,Tokyo, Japan2
Department of Orthopaedic Surgery, International University of Health andWelfare, Mita Hospital, Tokyo, Japan
3
Keio Spine Research Group, Tokyo, Japan
4
Department of Orthopaedic Surgery, Fujita Health University, Toyoake, Japan

Purpose: Several risk factors for the postoperative shoulder imbalance (PSI) in type 2 adolescent idiopathic scoliosis (AIS) were reported. We have noticed that the positionof upper end vertebra (UEV) in proximal thoracic curve
might have influenced the postoperative shoulder balance.
We investigated the risk factors of PSI in patients with
type 2 AIS including the position of preoperative UEV.
Methods: A total of 126 type 2 AIS patients who underwent posterior correction and fusion surgeries from 2008
to 2018 were included. We included only patients whose
upper instrumented vertebra were selected at T2. The
patients were divided into two groups based on radiologic shoulder height (RSH) 2 years after surgery. The
patients with RSH more than 10 mm were included in the
PSI group, and the others were included in the non- PSI
group. UEV, RSH, Cobb angle, curve flexibility, T1 andT2 tilt, correction rate, Risser grade, Scoliosis ResearchSociety-22 scores, and demographic data were compared
between the two groups using independent t-tests or chisquare tests. The variables with p-value <0.20 in univariate
analysis were assessed in logistic regression analysis.
Results: Seventy-one patients were included in this study(mean age, 14.1±2.0 years; range, 10–19 years). Thirtyfour patients in the PSI group and 37 patients in the nonPSI group were analyzed. UEV was T1 in 49 patients andT2 in 22 patients. Univariate analysis showed that there
were more patients with UEV at T1 (PSI: 85%, non- PSI:
54%; p<0.01) and Risser grade ≥3 (PSI: 88%, non-PSI:62%; p<0.05) in the PSI group than in the non-PSI group.

Asian Spine Journal
Regarding preoperative radiographic parameters, the mean
Cobb angle of the main thoracic curve and RSH tended tobe larger and the mean T2 tilt tended to be smaller in the
PSI group than in the non-PSI group. Logistic regression
analysis revealed that UEV at T1 (odds ratio [OR], 4.1;
95% confidence interval [CI], 1.2–14.4; p<0.05) and Risser
grade ≥3 (OR, 3.9; 95% CI, 1.1–14.5; p<0.05) are significantly associated with PSI. There were no differences in the
preoperative and final Scoliosis Research Society-22 scores,
in total or in any domain, between the two groups
Conclusions: UEV at T1 and Risser grade ≥3 at the timeof surgery are significant risk factors of PSI. The level of
UEV in proximal thoracic curve should be considered inplanning for posterior correction surgery as for avoiding
PSI in patients with type 2 AIS.

PS-FP-5-60

A Novel Intraoperative Spino-Pelvic Parameter“Thoracic 10 Pelvic Angle” Can Predict Proximal
Junctional Kyphosis after Adult Spinal
Deformity Surgery
Norihiro Isogai1,2, Yutaka Sasao1,2, Kenshi Daimon1,3,
Shigeto Ebata1,3, Haruki Funao1,2,3, Ken Ishii1,2,3
1

Department of Orthopaedic Surgery, School of Medicine, International
University of Health and Welfare (IUHW), Otawara, Japan2
Department of Orthopaedic Surgery, International University of Health andWelfare (IUHW) Mita Hospital, Tokyo, Japan3
Department of Orthopaedic Surgery, International University of Health andWelfare (IUHW) Narita Hospital, Narita, Japan

Purpose: Previous studies reported several risk factors
for proximal junctional kyphosis (PJK) after adult spinal
deformity surgery. However, there was no report describing the correlation between the pelvic tilt (PT) and T10
vertebral body. Here we proposed a novel intraoperative
spino-pelvic parameter “thoracic 10 pelvic (T10P) angle”,
and investigated the risk factors for PJK.
Methods: Forty-seven patients who underwent adultspinal deformity surgery were enrolled. All patients werefused to the pelvis. We excluded the patients whose upper
instrumented vertebra was above T9. The patients weredivided into two groups based on the development of PJK
at 2 years after surgery. T10P angle was defined as theangle between the line connecting the midpoint of sacral
plate to the femoral head axis and the line connecting the

S85

center of T10 vertebral body to the midpoint of sacral
plate. Preoperative and postoperative spino-pelvic parameters (pelvic incidence [PI], lumbar lordosis [LL], PT, PI–
LL, T10P angle), age, gender, and T-score were measured,and statistical analyses were performed using independentt-tests, chi-square test, and correlation coefficient.
Results: PJK was observed in 19% (9/47 patients), andthey were divided in to the PJK group. Thirty-eight patients were divided into the control group. There were
no differences between the two groups in PI (PJK group:
51.8°/control group: 51.2°), preoperative LL (7.6°/12.7°),
postoperative LL (35.9°/40.3°), preoperative PT(35.8°/31.8°), postoperative PT (22.9°/21.4°), preoperative PI–LL (44.2°/37.8°), postoperative PI–LL (15.9°/9.9°),
preoperative T10P angle (38.2°/33.3°), postoperative T10P
angle (15.8°/15.3°), age, gender, and T-score. Although
there were 13/38 patients (34%) with postoperative T10P
angle over 20° or under 0° in the control group, there were
7/9 patients (78%) with postoperative T10P angle over 20°
or under 0° in the PJK group (p<0.05). The linear correlation coefficient revealed that the postoperative PT werestrongly correlated with the intraoperative T10P (r=0.80,
p<0.05), and were calculated by the equation ‘the postoperative PT=0.77×intraoperative T10P angle+9.2°.
Conclusions: T10P angle should be corrected between 0
to 20°. T10P angle enable us to predict postoperative PT
and the development of PJK, surgical correction would be
adjusted intraoperatively.

PS-FP-5-62

Differences in Natural Walking for Elderlies by
the Degree of the Low Back Pain: Gait Analysis
with KINECT
Yuh Watanabe1, Yu Yamato1,2, Tomohiko Hasegawa1,
Go Yoshida1, Tomohiro Banno1, Hideyuki Arima1,
Yuki Mihara1, Shin Oe1,2, Hiroki Ushirozako1,
Tomohiro Yamada1, Koichiro Ide1, Keiichi Nakai1,
Kenta Kurosu1, Yuya Takahashi3, Haruo Niwa3,
Hironobu Hoshino1, Yukihiro Matsuyama1
1

Department of Orthopedic Surgery, Hamamatsu University School of
Medicine, Hamamatsu, Japan
2
Division of Geriatric Musculoskeletal Health, Hamamatsu University Schoolof Medicine, Hamamatsu, Japan3
Department of Total Care Internal Medicine, Toei Medical Center, Toei, Japan

Purpose: The objective of this research is to reveal theS86

Asian Spine J 2021;15(Supplement 1):S1-S177

characteristics of trunk inclination while walking differedby the degree of low back pain.
Methods: Elderlies who interested and voluntary-gathered
dwellers for this study were researched at Toei town inJapan, between May and October 2019. A total of 88 subjects (31 men, 57 women) who answered the Oswestry
Disability Index (ODI) questionnaire survey and joined
the gait evaluation were included. Each subject was categorized into two groups (threshold of ODI 20%): thelow back pain group (LBPG: ODI 20% or more) and thehealthy group (HG: ODI 0% to 19%). Each gait was evaluated with a portable gait analyzer AKIRA (System Friend
Co. Ltd.) which equips KINECT (Microsoft Co. Ltd.).
Each natural walking was analyzed, and evaluated factors
are as follows: stride length and width, velocity, and trunk
inclination angle (from mid-pelvis to cervical crest) during walking.
Results: The total of 88 subjects were categorized into
LBPG for 25 participants (average age, 81.8 years; ODI,
33.5%; height, 149.7 cm; weight, 57.4 kg; body mass index[BMI], 25.5 kg/m2) and HG for 63 participants (averageage, 76.5 years; ODI, 8.0%; height, 154.4 cm; weight, 55.0kg; BMI, 22.2 kg/m2). On average, the LBPG has stride
length 0.491 m, width 0.149 m, velocity 60.8 m/min, trunk
forward inclination 20.1°, and trunk backward inclination-4.6°. On the other hand, the HG has stride length 0.578
m, width 0.133 m, velocity 74.2 m/min, trunk forward
maximum inclination of 7.4°, and trunk backward maximum inclination -0.4° on average. The stride length in the
LBPG (0.491 m) was smaller than that in the HG (0.578 m)(p=0.004). The width in the LBPG (0.149 m) was larger
than that in the HG (0.133 m) (p=0.041). The velocity inthe LBPG (60.8 m/min) was slower than that in the HG(74.2 m/min) (p=0.004). The trunk leaning forward during walking in the LBPG (20.1°) was larger than that in
the HG (7.4°) (p=0.048). The difference in trunk inclination suggested that the necessary muscle activity pattern
to stabilize the spinal-column during walking may be different by the degree of low back pain.
Conclusions: The elderlies with high ODI have wide steps,
short strides, and big trunk inclination ranges while theywalk.

PS-FP-5-63

Clinical Relationships between Spinopelvic
Parameters and Lumbar Disc Degeneration in
Different Disc Regions
Kazuhiro Inomata, Yoichi Iizuka, Eiji Takasawa,
Tokue Mieda, Sho Ishiwata, Yohei Kakuta, Akira Honda,
Yusuke Tomomatsu, Shunsuke Ito, Hirotaka Chikuda
Department of Orthopaedic Surgery, Gunma University Graduate School of
Medicine, Maebashi, Japan

Purpose: The pathology of lumbar disc degeneration(LDD) remains unknown, although it is associated withgenetic, mechanical, and lifestyle factors. The purpose ofthis study was to clarify the clinical relationship spinopelvic parameters and the LDD.
Methods: A total of 58 patients (37 males and 21 females;mean age, 69.1 years old) who underwent surgery for
lumbar spinal canal stenosis were retrospectively reviewed. Using magnetic resonance imaging, the grade of
LDD was assessed according to the Pfirrmann classification at the L1/2 to L5/S1 levels. Spinopelvic parameters onwhole-spine standing radiography were analyzed, including the coronal Cobb angle, sagittal vertical axis, thoracic
kyphosis, lumbar lordosis (LL), sacral slope (SS), pelvic
tilt, pelvic incidence (PI), and L1–L5 range of motion(ROM). The age, sex, smoking history, alcohol consumption, and comorbidity (diabetes mellitus [DM]) were also
recorded.
Results: There was a positive correlation between the age
and LDD grade at all disc levels, while no correlation was
found between the coronal Cobb angle, sex, smoking history, alcohol consumption, and DM and the LDD. The
correlation and multivariate regression analyses (adjusted
for age and sex) showed that decreasing ROM and loss of
LL and SS were correlated with the LDD at the L1/2 andL2/3 levels and the L5/S1 disc level, respectively; a low PI
was correlated with the LDD at the L4/5 and L5/S1 disclevels.
Conclusions: This study showed that the pathology of
LDD may differ depending on the disc level. Disc degeneration in the upper lumbar region was associated withdecreasing in ROM. In contrast, disc degeneration in thelower lumbar region was associated with spinopelvic sagittal alignment but not with coronal alignment.

Asian Spine Journal
PS-FP-5-64

Three-Rod Correction Technique for Severe
Neuromuscular Scoliosis
Toru Yamaguchi, Haruhisa Yanagida, Kazuyuki Takamura,Tomoyuki Nakamura
Department of Orthopaedic and Spine Surgery, Fukuoka Children’s Hospital,
Fukuoka, Japan

Purpose: In severe neuromuscular scoliosis surgery, simple rodding to multiple pedicle screws is often difficult.
To improve this issue, we have developed three-rod correction technique. In this technique, two rods are placedat the cephalad and caudal anchors on the concave side
and connected by the cantilever technique, then followedby distraction between the two rods, and the translation
with sublaminar tapes at the apex. After that, the single
rod is placed on the convex side. Objective of this study isto evaluate the efficacy and safety of three-rod correction
technique for severe neuromuscular scoliosis.
Methods: Twenty-four patients (male 8, female 16) withneuromuscular scoliosis over 90° were investigated. Meanage at operation was 14.2±3.5 years. Patients were divided
into two groups: one is treated by posterior spinal fusion(PSF) with multi-segmental pedicle screws (group M:
GM, n=11); the other is by PSF with three-rod correction
technique (group T: GT, n=13). We retrospectively investigated operation time (OT), estimated blood loss (EBL),
range of fixation, peri- and postoperative complications
on medical record and Cobb angle (CA), pelvic obliquity(PO), thoracic kyphosis (TK, T2–12), and lumbosacral
lordosis (LS, L1S1) on plain X-ray film at preoperationand final follow-up.
Results: Mean OT (min) was 388±76.5 (GM) and
444.4±78.3 (GT) (p=0.09), respectively. EBL (g) was GM
2,389±1,273 and GT 2,414±1,485 (p=0.9). Upper instrumented vertebra were upper thoracic (T1-4) and lower
instrumented vertebra were L4 (4), L5 (5), and S1(15).
Complications are seven excessive bleeding (GM, 4; GT,3), three pulmonary related (GM), two proximal junctional kyphosis (GM, 1; GT, 1), one late surgical site infection (GM), and urinary tract infection (GM). CA (GM,105°±16.4°; GT, 122°±15.5°; p=0.001) were corrected to
41.4°±15.5° (GM), 54.1°±15.8° (GT) (p=0.059) and correction rate (%) were 60.7±14.6 (GM) and 55.9±11 (GT)(p=0.36). PO 21.8°±15.3° (GM) and 25.1°±10.5° (GT)S87

(p=0.57) were corrected to 8.6°±6.7° (GM) and 10.6°±6.6°(GT) (p=0.51). TK 20.6°±30.1° (GM) and 49.8°±32.5°(GT) (p=0.03) were corrected to 27.5°±21.9° (GM),
37.1°±18.4° (GT) (p=0.09). LS -27.5°±39.7° (GM) and-46.5°±37.7° (GT) (p=0.24) were corrected to -44.7°±14.1°(GM) and -47.3°±12.9° (GT) (p=0.65).
Conclusions: Three-rod correction technique could correct severe neuromuscular scoliosis with less complications.

PS-FP-5-66

Influence of Pelvic Obliquity on Postoperative
Coronal Radiographic Parameters in Patientswith Lenke Type 5 Adolescent Idiopathic
Scoliosis at Minimum 5-Year Follow-up
Takahito Iga, Satoshi Suzuki, Satoshi Nori, Osahiko Tsuji,
Narihito Nagoshi, Eijiro Okada, Mitsuru Yagi,
Masaya Nakamura, Morio Matsumoto, Kota Watanabe
Department of Orthopedic Surgery, Keio University School of Medicine,Tokyo, Japan

Purpose: Preoperative pelvic obliquity in patients withadolescent idiopathic scoliosis (AIS) may have an impact
on postoperative radiographic alignment on non-fused
segments, but there is very little information about it. We
analyzed the influence of preoperative pelvic obliquity on
postoperative coronal radiographic parameter in patientswith AIS Lenke type 5.
Methods: Thirty cases of Lenke type 5 with a mean ageof 14.6±1.8 years were investigated retrospectively. They
were classified into two groups (≥5° group, <5° group) according to the angle (sacral takeoff angle–iliac takeoff angle). We compared the reviewed the coronal radiographic
parameters at postoperative 2 and 5 years between theboth groups.
Results: The ≥5°group had significantly larger wedging
angle of the lower adjacent intervertebral disc (p<0.05,
9.1°±3.2° [≥5° group] vs. 5.9°±3.2° [<5° group]) at postoperative 2 years and (p<0.01, 9.0°±2.8° [≥5° group] vs.
4.9°±3.1° [<5° group]) at postoperative 5 years. No significant difference of wedging angle between 2 and 5 years
postoperatively was observed in the both groups. The ≥5°group had significantly lower correction of lumbar Cobb
angle (p<0.05, 51.1°±19.3° [≥5° group] vs. 67.2°±17.5° [<5°S88

Asian Spine J 2021;15(Supplement 1):S1-S177

group]) at postoperative 5 years. No significant differenceswere observed between the two groups for age, Rissergrade, correction rate of T-cobb angle, lowest instrumented vertebra-central sacral vertical line (CSVL), and C7CSVL.
Conclusions: The ≥5° group had larger wedging angle andless correction rate of lumbar Cobb angle than those of<5° group postoperatively, and the values were continued
until postoperative 5 years. Preoperative pelvic obliquity
may be a critical consideration in selecting distal andproximal fusion level when planning corrective surgery inpatient with AIS.

PS-FP-5-67

Can Bone Improvement after 2-Year Calcium+
Vitamin-D Supplementation Be Maintained in
Idiopathic Scoliosis after 4-Year of Treatment
Discontinuation: A Prospective Randomized
Double-Blinded Placebo-Controlled Trial
Tsz Ping Lam1,2, Guangpu Yang1,2, Henry Pang1,2,
Wayne Yw Lee1,2, Alec Lik-Hang Hung1,2,
Jack Chun-Yiu Cheng1,2
1

SH Ho Scoliosis Research Lab, Joint Scoliosis Research Center of the Chinese
University of Hong Kong and Nanjing University, Hong Kong SAR, China
2
Department of Orthopaedics & Traumatology, The Chinese University ofHong Kong, Hong Kong SAR, China

Purpose: Adolescent idiopathic scoliosis (AIS) is associated with low bone mass which could persists into
adulthood. Given that AIS girls have low dietary calcium
intake and high prevalence of vitamin-D (Vit-D) insufficiency, our group has previously reported the first 2-year
randomized double-blinded placebo-controlled trial withcalcium (Ca) and Vit-D supplementation to AIS girls withlow bone mass (the Cal study) showing strong evidencesof bone accretion with Ca+Vit-D supplementation. This
study was an extension of the Cal study to address the important issue whether bone density and quality improvement from the initial 2-year Ca+Vit-D supplementation
could persist as subjects approached peak bone mass at
6-year, i.e., after 4-year of supplement discontinuation.
Methods: This was a randomized double-blinded placebocontrolled trial on AIS girls (range, 11–14 years old; meanage, 12.9 years; Tanner stage <IV) with femoral neck areal
bone mineral density (aBMD) Z-score <0 and Cobb angle≥15°. A total of 330 subjects were randomized to group 1(placebo), group 2 (600 mg Ca+400 IU Vit-D 3/day), orgroup 3 (600 mg Ca+800 IU Vit-D 3/day) for 2-year treatment. Investigations were done at baseline, 2-year and6-year including high-resolution peripheral quantitative
computed tomography at distal radius and dual-energy
X-ray absorptiometry at proximal hips. Analysis of covariance was used for analysis. A p-value <0.05 was considered statistically significant.
Results: A total of 270 subjects (81.8%) completed thetreatment. At 2-year time-point, the increases in serum
25(OH)Vit-D, left femoral neck aBMD (group 3), trabecular volumetric BMD, trabecular bone volume to tissue
volume ratio, and trabecular number were significantly
greater in group 2 and 3 than in group 1 (p<0.05). At
6-year follow-up after 4-year discontinuation of supplementation at a mean age of 19.2 years during the earlyphase of peak bone mass, no difference was noted except
increase in cortical thickness being greater only in group
3 than in group 1.
Conclusions: This study provided strong evidences that2-year supplementation with Ca+Vit-D improved bonehealth for low bone mass in AIS. At 6-year follow-up with
4-year discontinuation of treatment, the treatment effectmostly regressed towards the null hypothesis indicating
the need to continue supplementation in order to maintain the therapeutic effect on bone health up to the stageof peak bone mass. This study is supported by Research
Grants Council of the Hong Kong S.A.R., China (projectno., 14130216 and 14174517).

PS-FP-5-72

The Impact of Growing Rod Surgery for Early
Onset Scoliosis on the Cervical Spine Sagittal
Alignment
Shuhei Ito1,2, Satoshi Suzuki1, Satoshi Nori1,
Osahiko Tsuji1, Narihito Nagoshi1, Eijiro Okada1,
Mitsuru Yagi1, Masaya Nakamura1, Morio Matsumoto1,
Kota Watanabe1
1Department of Orthopaedic Surgery, Keio University School of Medicine,Tokyo, Japan2
Department of Orthopaedic Surgery, National Organization Tokyo Medical
Center, Tokyo, Japan

Purpose: The sagittal plane alignment of the cervical spine

Asian Spine Journal
is thought to be correlated with the patient’s quality of life.
The postoperative sagittal alignment of the cervical spine
correlates with thoracic spine alignment in adolescent andadult scoliosis patients. Therefore, the cervical spine alignment of early onset scoliosis (EOS) patients who undergo
surgery is thought to be affected by the instrumented thoracolumbar spine; however, there is no reports about EOS
patients. In this study, we evaluated the effect of growing
rod (GR) surgery on cervical sagittal alignment in patientswith EOS.
Methods: This study includes 21 EOS patients (four males
and 17 females; mean age, 8.6 years at first surgery) who
underwent GR surgery at single institution between 2004
and 2017 and were followed up until final fusion (FF) surgery. Cobb angle in main thoracic curve, C2–7 angle, T1
slope, thoracic kyphosis (TK, T2–12), and sagittal verticalaxis (SVA) were evaluated retrospectively at pre-surgery,post-index surgery, pre-FF, and post-FF (final follow-up).
The patients were divided into a good cervical lordosis
group (C2–7 angle after FF <-10°) and a poor cervicallordosis group (C2–7 angle ≥-10°). The radiographic parameters were compared between the two groups and thecorrelation analyses were performed.
Results: The Cobb angle and TK decreased significantly
after the first operation and were well maintained until FF(preoperative vs. post-FF; Cobb 76.9° vs. 30.4°, TK 35.9°
vs. 21.3°). The C2–7 angle and T1 slope tended to decrease
after FF but without significant difference. SVA showedno significant changes. Patients in the poor group showeda significantly smaller preoperative C2–7 angle and postoperative T1 slope than those in the good group (good:
n=14, poor: n=7). There was a strong positive correlation
between postoperative C2–7 angle and postoperative T1
slope (0.829, p=0.00). Furthermore, there was a positive
correlation between postoperative C2–7 angle and preoperative C2–7 angle (0.443, p=0.023) or postoperative TK(0.449, p=0.021).
Conclusions: Thirty-three percent of patients who underwent GR surgery had poor cervical sagittal alignment after FF. These patients had a significantly smaller T1 slope
after FF, and C2–7 angle positively correlated with T1
slope and TK. Therefore, cervical sagittal alignment could
be adversely affected by distraction force in GR surgery.

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PS-FP-5-73

Scoliosis in Osteogenesis Imperfecta: Qualityof Life and Surgical Impact
Janus S. H. Wong1, Jason P. Y. Cheung1,
Prudence W. H. Cheung1, Ya Peng Zhou2,
Michael K. T. To1,2
1

Department of Orthopaedics & Traumatology, University of Hong Kong,
Hong Kong
2
Department of Orthopaedics & Traumatology, The University of Hong
Kong-Shenzhen Hospital, Shenzhen, China

Purpose: Spinal deformity is prevalent among patientswith osteogenesis imperfecta (OI), but little is known
about its impact on quality of life. We hypothesize thatscoliosis in OI patients is associated with lower quality oflife; scoliosis surgery improves treatment satisfaction.
Methods: OI patients were recruited through the University of Hong Kong Shenzhen Hospital, one of the largest
tertiary OI referral centers in China in this cross-sectional
epidemiological study. Patients with a confirmed clinical or genetic diagnosis of OI were invited to complete
an electronic questionnaire where patient demographics,
health seeking behavior, treatment received, radiographs,
and quality of life measures (in validated Chinese versionsof Scoliosis Research Society-22 Questionnaire [SRS-22]
and EuroQol 5-dimensional-5 levels) were assessed. OI
patients were divided into the following groups: no scoliosis with Cobb angle <10°, scoliosis of Cobb angle between
10° and 50° without receiving treatment, scoliosis of Cobb
angle over 50° without receiving treatment, scoliosis treated with bracing only, and scoliosis treated with surgery.
Patients without a confirmed diagnosis of OI, or without
radiographs for assessment of spinal deformities were excluded.
Results: A total of 148 OI patients (101 with scoliosis[male, 60; female, 41; mean age, 16.5 years] and 47 without scoliosis) were analyzed. The scoliosis group had
lower self-image (3.31 vs. 3.70, p=0.003) and mobility (3.13
vs. 3.66, p=0.015). Within the scoliosis groups, the median
Cobb angle for the primary curve was 34.5 (interquartile range, 16.8–58.4), with elder patients having greater
curves (ρ=0.544, p<0.001). Curve magnitude was associated with pain (ρ=- 0.355, p<0.001) and anxiety (ρ=-0.352,
p<0.001), but inversely correlated with function (ρ=0.225, p=0.024), self-image (ρ=-0.379, p<0.001), and total
SRS score (ρ=-0.283, p=0.004). Eleven point nine percent

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Asian Spine J 2021;15(Supplement 1):S1-S177

underwent scoliosis surgery, 13.9% underwent bracing,and 41.6% underwent physiotherapy. Fourteen point nine
percent reported that they did not receive any treatment
for scoliosis because they did not have the means, while
23.8% were not aware or uncertain whether they had
scoliosis. Brace compliance was poor with only 18.2%
reporting brace wear >20 hours per day. Patients treated
operatively reported higher treatment satisfaction scores(4.41 vs. 3.43, p=0.002) than patients with scoliosis of
Cobb angle over 50° without receiving treatment, despite
similar curve magnitudes (p=0.354).
Conclusions: This is the largest quality of life study of scoliosis among OI patients to date. OI patients with scoliosis
reported lower self-image and mobility. Curve magnitude
was associated with older age, pain, and anxiety and wasinversely correlated with function, self-image, and total
SRS score. Patients who received surgery reported higher
treatment satisfaction than those managed nonoperatively.

PS-FP-5-74

Machine Learning for Predicting MechanicalComplication after Adult Spinal Deformity
Surgery
Sung Hyun Noh1, Yoon Ha2, Kyung Hyun Kim3
1

Department of Neurosurgery, Ajou University College of Medicine, Suwon,
Korea
2
Department of Neurosurgery, Spine and Spinal Cord Institute, Severance
Hospital, Yonsei University College of Medicine, Seoul, Korea
3
Department of Neurosurgery, Spine and Spinal Cord Institute, Gangnam
Severance Hospital, Yonsei University College of Medicine, Seoul, Korea

Purpose: There have been many methods to prevent mechanical complication after adult spinal deformity (ASD)
surgery, but mechanical complication cannot be avoided
in ASD surgery. A modified Global Alignment and Proportion (GAP) scoring system equipped with a body massindex (BMI) and bone mineral density (BMD) (GAPB)
system developed predictive values of mechanical complications after ASD surgery. Further, the purpose of thisstudy is to create an ideal model through machine learning to predict mechanical complication in ASD surgery.
Methods: Between January 2009 and December 2018, 238
consecutive patients with ASD received at least 4 level
fusions and were followed for at least 2 years. Data collec-

tion included demographic and radiologic examinations.
The sample was stratified into groups: 167 cases (70%) for
training, 71 cases (30%) for performance testing. The data
were used as input to some machine learning algorithms,
including logistic regression (LR), random forest (RF) gradient boosting system (GBS), and deep neural networks(DNN). The performance of algorithm was evaluated by
the area under the curve (AUC) and accuracy using test
data.
Results: The patients’ average age and follow-up period
were 67.1±6.17 years and 28.54±4.25 months, respectively.
Statistical differences between complication and noncomplication groups were as follows: BMI, BMD, relative
pelvic version score, relative lumbar lordosis score, relative sagittal alignment score of GAP score were statistically significant in the training set and the test set (p<0.05).
The AUC in the training set of LR, GBS, RF, and DNN
model were 0.871 (0.817–0.925), 0.942 (0.911–0.974),
1.000 (1.000–1.000), and 0.947 (0.915–0.980). The accuracy in the training set of LR, GBS, RF, and DNN were 0.784(0.722–0.847), 0.868 (0.817–0.920), 1.000 (1.000–1.000),
and 0.856 (0.803–0.909). The AUC in the testing set of LR,
GBS, RF, and DNN model were 0.785 (0.678–0.893), 0.808(0.702–0.914), 0.810 (0.710–0.910), and 0.730 (0.610–
0.850). The accuracy in the testing set of LR, GBS, RF, and
DNN were 0.732 (0.629–0.835), 0.718 (0.614–0.823), 0.732(0.629–0.835), and 0.620 (0.507–0.733). RF achieved thebest prediction performance on testing dataset and independent testing dataset.
Conclusions: This study created a comprehensive model
to predict mechanical complications after ASD surgery.
It was found that RF is the most appropriate model toreduce mechanical complications after ASD surgery. This
information can be used to preventing mechanical complications to the surgeon and patient in ASD surgery.

Asian Spine Journal
PS-FP-5-75

Defining Spino-Pelvic Alignment in Adult
Population Over 60 Years Old: Prospective
Analysis of 214 Volunteers
Sung Hyun Noh1, Kyung Hyun Kim2, Yoon Ha3
1

Department of Neurosurgery, Ajou University College of Medicine, Suwon,
Korea
2
Department of Neurosurgery, Spine and Spinal Cord Institute, Gangnam
Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
3
Department of Neurosurgery, Spine and Spinal Cord Institute, Severance
Hospital, Yonsei University College of Medicine, Seoul, Korea

Purpose: The values of the surgical target angle and ideal
sagittal balance that have been published so far are theresults of a study targeting patients over 18 years of age.
However, most patients in adult spinal deformity surgery
are currently in their 60s or older, and it is unreasonable
to apply these values to patients in their 60s or older. The
purpose of this study is to prospectively analyze adult patients to obtain the ideal sagittal balance value at age 60 orolder.
Methods: A total of 214 people over the age of 60 participated in the study. Questionnaires related to healthrelated quality of life (HRQOL) were administered. Spinopelvic parameters were measured by whole spine X-rays.
Radiographical evaluation was conducted on the lateralplanes and HRQOL questionnaires (Oswestry Disability Index [ODI]) were completed. Multivariate logistic
regression analysis was conducted to analyze radiologic
parameters related with ODI. Radiographical parameters
demonstrating highest correlation with HRQOL values
were evaluated to determine thresholds predictive of ODI
more than 20.
Results: Two hundred fourteen consecutive patients (meanage, 71.3 years) were enrolled. There were 131 people withan ODI value of less than 20 (minimal-ODI group) and83 people with an ODI value of 20 or more (moderateODI group). Moderate-ODI group had greater pelvic tilt(PT) (28°±13.7° vs. 19.9°±13.9°, p<0.05), greater T1 pelvic
angle (T1PA) (33.6°±15° vs. 23.7°±14.6°, p<0.05), andgreater pelvic incidence/lumbar lordosis PI/LL mismatch(PI–LL) (45.2±30.7 vs. 31.7±36.1, p<0.05) than minimalODI group. Moderate-ODI group demonstrated greater
disability on ODI measures compared with minimal-ODI(ODI 25.3±4.3 vs. 11.8±5.4, p<0.05). Pearson analysis
demonstrated that among all parameters, PT, T1PA, and

S91

PILL correlated most strongly with disability for bothminimal-ODI and moderate-ODI groups (p<0.001). Logistic regression models demonstrated threshold radiographical spinopelvic parameters for ODI more than 20
to be: PT 15° or more (area under curve [AUC]=0.820),
T1PA 17° or more (AUC=0.888), and PI−LL 16° or more
(AUC=0.842).
Conclusions: As you age, degenerative changes progress.
Prospective analysis of consecutively enrolled age 60
or older patients proved that PT, T1PA, and PI−LL can
predict patient disability and provide evaluation guides
for appropriate treatment decisions. Threshold values formoderate disability (ODI >20) included: PT 15° or more,
T1PA 17° or more, and PI−LL 16° or more.

PS-FP-5-76

Which Domain or Factors Of 36-Item ShortForm Health Survey Impact on Patient
Satisfaction after Adult Spinal Deformity
Correction Surgery?
Hyun Jun Jang, Jeong Yoon Park, Dong Kyu Chin,
Young Seol Yoon, Keun Su Kim, Yong Eun Cho,
Kyung Hyun Kim
Department of Neurosurgery, Spine and Spinal Cord Institute, Gangnam
Severance Hospital, Yonsei University College of Medicine, Seoul, Korea

Purpose: Increasing patient satisfaction is one of the key
goals in adult spinal deformity (ASD) surgery. The 36item Short Form Health Survey (SF-36) consists of eight
domains and is very widely used, but the study of the association between each domain and satisfaction is limited.
Our objective was to evaluate the relationship between
patient satisfaction, Oswestry Disability Index, SF-36 domains, and radiographic measures at 2 years after surgery.
Method: A single center prospective database of ASD surgery was retrospectively reviewed. The correlation coefficients between demographics, radiographic parameters,
health-related quality of life (HRQOL) including SF-36 8
domains and Scoliosis Research Society-22 questionnairesatisfaction scores at 2 years (Sat-2y). The patients weredivided into highly satisfied and less satisfied group according to Sat-2y and compared each factor.
Results: A total of 41 patients who underwent thoracolumbar fusion for ASD and had a minimum of 2-year

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Asian Spine J 2021;15(Supplement 1):S1-S177

follow-up was collected. All HRQOL subdomains andseveral sagittal radiographic parameters had significantly
improved 2 years after surgery. In SF-36, Sat-2y was moderately correlated with general health (GH) (r=0.51), roleemotional (RE) (r=0.51) domain at 2 years after surgery,not correlated with role physical, weakly correlated withthe remaining domains. There were no differences in demographics and radiologic outcomes between the highly
satisfied and less satisfied groups, and there were betterscores in SF-36 GH, RE, and bodily pain in highly satisfied group.
Conclusions: GH and RE may be useful goal in improving
patient satisfaction with management at 2 years after ASD
surgery. Surgeon should pay attention to these domains
for patient satisfaction.

PS-FP-5-80

Preoperative Distraction of Severe Caries
Kyphotic Spine Deformities with Modified
Halo-Pelvic Distraction AssemblyAmer Aziz, Muhammad Saad Ilyas
Department of Orthopedics and Spine Surgery, Ghurki Trust Teaching
Hospital, Lahore, Pakistan

Purpose: Halo-traction device has been seen with favorable outcome in preoperative management of with severe
kyphotic deformities; however, associated complications
are inevitable. Modifications in assembly can improve theoutcome and clinical efficacy. Objective of the present
study was to evaluate the clinical efficacy of our modified
halo-pelvic distraction device for managing severe kyphotic deformity before definitive surgery.
Methods: Three cases of caries spine presented with severe kyphotic deformity (OMGEA spine deformity) weremales of 14, 10, 36 years of age. The 1st had kyphotic
angle of 141° from T1 to T10 vertebrae and complete lossof power of both lower limbs, and the other two had kyphotic angle of 162° from T7 to T12 and 159° from T7 to
L2 vertebra, respectively. The third also had complete lossof power at both lower limbs. A modified halo-pelvic distraction device comprised of halo and pelvic assembly wasapplied before definitive surgery. The halo-ring was connected to head with 06 pins, while pelvic assembly had Ilizarov half pins connected to two arches allowing patients

to lie supine in bed. Two Ilizarov half pins were placedin the supra-acetabular region for sturdy anchorage, twowere 10 cm posterior to the anterior superior iliac spine,and muscles were not pierced for placement of wires orpins that minimized the risk of infection and pain. The
assembly had four rods, and set of two were placed anterolateral and posterolateral each, to provide balanced
distraction forces. Distraction at the rate of 3 mm/day wasstarted from first postoperative day for 35 days in first and
45 days each for 2nd and 3rd patients.
Results: The neurology in 1st patient improved in both
lower limbs to grade 2 on 5th post-distraction day andafter 35 days kyphotic angle reduced to 56°. The neurology remained intact in 2nd patient while in third patient,neurology improved to 3/5 in both lower limbs after 7
days of distraction, kyphotic angle reduced to 76° and
70° respectively after 45 days of distraction. At the endof distraction, definitive surgery was done and a standalone titanium cage was placed at the affected levels after
debridement through an anterior approach. No peri- or
postoperative complications were observed.
Conclusions: Gradual correction through preoperative
halo-pelvic distraction can be safe and effective in severe
caries spine kyphotic deformities. Our modified assembly
will be useful for spine surgeon in these cases as no neurological and other complications were observed duringperi or postoperative period.

PS-FP-5-82

Which Health-Related Quality of Life Assessment Tool, Patient-Reported Outcomes
Measurement Information System, Revised
Scoliosis Research Society-22, or Oswestry
Disability Index, Is More Sensitive in Assessing
Outcomes of Primary versus Revision Adult
Spinal Deformity Surgery?
Tsung-Cheng Yin1, Munish C. Gupta2
1

Division of Spine Surgery, Department of Orthopaedic Surgery, Kaohsiung
Chang Gung Memorial Hospital, Kaohsiung, Taiwan
2
Department of Orthopaedic Surgery, Barnes-Jewish Hospital, Washington
University, St. Louis, MO, USA

Purpose: The Patient-Reported Outcomes Measurement
Information System (PROMIS) has been recognized tobe essential in assessment of the effectiveness of our clini-

Asian Spine Journal
cal interventions. However, there is a paucity of literatureusing the PROMIS instruments in assessing the healthrelated quality of life (HRQoL) of primary and revision
surgery in adult spinal deformity (ASD).
Methods: All patients were enrolled with different PROs
evaluation from preoperative to minimum 2 years postoperative time point. PROMIS, revised Scoliosis ResearchSociety-22 (SRS-22r), Oswestry Disability Index (ODI),
patient demographic data, and X-ray parameters wereobtained at 3-time points: preoperatively, 1- and 2 years
postoperative.
Results: A total of 86 ASD patients undergoing posterior
spinal fusion of ≥5 vertebral levels to the sacrum, performed from 2016 to 2017, at a single institution. A totalof 42 cases (48%) were primary surgery (P) and 44 (52%)
were revision surgery (R). Both groups had significant
HRQoL improvement from preoperative to 1- and 2 years
postoperative. Patients in the R group had worse baseline
HRQoL as compared with the P group. However, only
PROMIS could detect differences in outcomes between
primary surgery and revision surgery at 1 year postoperative, whereas SRS-22r and ODI showed no difference at 1
year postoperative between the two groups.
Conclusions: The majority of HRQoL improvement occurs within the 1 year postoperative in ASD patients.
PROMIS domains are not only more efficient in administration, they are also more sensitive in assessing outcome
differences between primary and revision surgery at preoperative, 1- and 2 years postoperative compared to otherlegacy instruments (SRS-22r and ODI).

PS-FP-5-83

Experiences of Early Air Travel with Pneumothorax
after Anterior Spinal Surgery: A Report of Three
Cases
Amy Yoke Foong Wong1, Choong Hoon Foo1,
Nur Aida Binti Faruk Senan1,
Mohamad Zaki Bin Hj Mohd Amin2, Chung Chek Wong1
1

Department of Orthopaedics, Hospital Umum Sarawak, Kuching, Malaysia
Department of Orthopaedics, University of Malaysia Sarawak, Kota
Samarahan, Malaysia
2

Anterior thoracic or thoracolumbar spinal surgery byretropleural approach always carries a risk of pneumo-

S93

thorax as its consequence. Conventionally the Aerospace
Medicine Association (AsMA) and the British Thoracic
Society (BTS) recommend 2 weeks delay of air travel forpatient with resolved postoperative pneumothorax. They
also label active pneumothorax as an absolute contraindication for commercial air travel. Such a delay always
causes psychological and financial stress to patients andfamily who are far from home. Here we report three patients with postoperative pneumothorax and insisted onearly air travel despite being informed of the possible consequences. We report the cases of three female patientswith adolescent idiopathic scoliosis (Lenke 5) treated at
Hospital Umum Sarawak. They each developed postoperative pneumothorax which remained stable and slowly
resolving on repeated chest radiographs at day 3. All threepatients flew home on the same day of their discharge,
and each retrospectively reported to be asymptomatic
throughout their journey home. We have observed threepostoperative pneumothorax patients travel home safely
by flight earlier than stipulated recommended guidelines.
However, the possibility of pneumothorax progressing
into tension pneumothorax during air travel cannot beignored. Until more evidences emerge, we still adhere to
AsMA and BTS guidelines.

PS-FP-5-84

R adiological Assessment of Pre- andPostoperative Shoulder Balance Following
Posterior Spinal Fusion for Lenke 2 Adolescent
Idiopathic Scoliosis
Takashi Namikawa1, Akira Matsumura1, Minori Kato1,
Hiroaki Nakamura2
1

Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka,Japan
2
Department of Orthopaedic Surgery, Osaka City University, Osaka, Japan

Purpose: To elucidate useful coronal parameters to control
shoulder balance in posterior spinal fusion surgery for
Lenke 2 adolescent idiopathic scoliosis (AIS).
Methods: A total of 33 patients were reviewed. Proximal
thoracic, main thoracic Cobb angle (pelvic tilt [PT] andmain thoracic [MT]), % correction of both curve (PTcurve [PTC] and MT curve [MTC]), T1 tilt, and shoulder
asymmetry by the radiographic soft tissue shadow (RSH)S94

Asian Spine J 2021;15(Supplement 1):S1-S177

were measured from preoperative, immediately postoperative and latest follow-up radiographs. PTC:MTC ratio
was defined as an index of PTC and MTC matching. The
amount changes in RSH (ΔRSH), T1 tilt (ΔT1 tilt), PTC(ΔPTC), MTC (ΔMTC), and PTC:MTC (ΔPTC:MTC)
from pre- to post-surgery was calculated. The relationshipbetween ΔRSH and other amount changes in other parameters was examined.
Results: A mean preoperative RSH of -12 mm waschanged to +9 mm immediately after surgery and improved to +6 mm at the latest follow-up. A mean PT and
MT were 44° and 64° before surgery, 18° (56%) and 12°(79%) immediately after surgery, and 17° (55%) and 17°(74%) at the latest follow-up, respectively. ΔRSH was significantly correlated with ΔT1 tilt, ΔPTC and ΔPTC:MTC.
Conclusions: Unlike RSH, T1 tilt is a parameter which canbe checked easily by intraoperative X-ray examination.
The results suggested that controlling and checking T1
tilt intraoperatively can be useful to avoid postoperative
shoulder imbalance. Sufficient PT curve correction what
is matched to MT curve correction would be necessary
not only to levelling T1 tilt but also to prevent postoperative shoulder imbalance.

PS-FP-5-85

Surgical Outcomes in Syndromic Scoliosis
with Neurofibromatosis
Tatsuo Kato, Koki Uno, Teppei Suzuki, Masaaki Ito,
Kohei Kuroshima
National Hospital Organization Kobe Medical Center, Kobe, Japan

Purpose: Spinal deformity surgery with neurofibromatosis(NF) is challenging. This study included 36 consecutive
patients with NF who underwent scoliosis surgery. We
evaluated the surgical outcome of spinal fusion for NF.
Methods: Fifteen cases were males and 21 cases werefemales, ranging in age from 2 to 49 years (mean age,
14.3±9.7 years) at the initial surgery. The surgical procedures were growth friendly in eight cases, anterior andposterior fusion in 24 cases, and only posterior fusion in
12 cases. We evaluated complications, number of surgeries, radiographic data, and health-related quality of life
(HRQOL) (Scoliosis Research Society-30 [SRS-30], Oswestry Disability Index [ODI]) at final follow-up. Mean

follow-up was 10.2±7.1 years postoperatively.
Results: Scoliosis was corrected from 68° to 43° at final
follow-up (correction rate=37.0%). Complications wereobserved in five cases (62.5%) of growth friendly surgery
and nine cases (32.1%) of spinal fusion surgery, including
four cases of adding-on, three cases of proximal junctional kyphosis, three cases of infection, three cases of rod
fracture, three cases of hook dislocation, and one case oflowest instrumented vertebra dislocation. Two patientsdied during follow-up: one due to malignant transformation of neurofibroma and the other due to sudden death
during bathing. The total number of surgeries was 3.8±4.1,
and unplanned additional surgery was 0.4±1.0. HRQOL
was SRS-30 (function 3.9±0.5, pain 4.6±0.4, self-image
3.7±0.5, mental-health 4.4±0.5, satisfaction 4.1±0.5) andODI (6.1%±8.0%). There were no significant correlations
between HRQOL and complications. Spearman’s correlation analysis was performed for each of the HRQOL
domains and scoliosis correction rate, but no correlation
was found for all of them. There was a significant correlation between satisfaction and Cobb angle at final followup (R=-0.41, p<0.05).
Conclusions: SRS-30 function, self-image, and satisfaction domain scores in NF patients tended to be lower thanthose of AIS patients after surgery. These results are related to various factors such as severe scoliosis curve, skinlesions, multiple surgeries, and so on. On the other hand,the complications didn’t affect the HRQOL at the final follow- up. Therefore, it may be important to provide appropriate additional treatment for complications even if thenumber of surgeries increases. We evaluated the surgicaloutcomes of NF with scoliosis. There was no significant
correlation between correction rate and HRQOL or complications and HRQOL. Good outcomes were obtainedfor pain and mental-health.

Asian Spine Journal

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PS-FP-5-86

PS-FP-5-87

Risk Factors for Lateral Translation in
Adult Idiopathic Adolescent Scoliosis withThoracolumbar/Lumbar Curves

Predictive Factors for Nighttime Bracing
Treatment Outcome in Adolescent Idiopathic
Scoliosis

Toshiaki Kotani1, Tsuyoshi Sakuma1, Yasushi Iijima1,
Keita Nakayama1, Yasuchika Aoki2, Kotaro Sakashita1,
Takahiro Sunami3, Kosuke Sato3, Tomoyuki Asada3,
Tsutomu Akazawa4, Kazuhide Inage5, Yasuhiro Shiga5,
Shohei Minami1, Seiji Ohtori5

Naoya Taki, Hideaki Watanabe, Ichiro Kikkawa

1

Department of Orthopedic Surgery, Seirei Sakura Citizen Hospital, Sakura,Japan
2
Department of Orthopedic Surgery, Eastern Chiba Medical Center, Togane,Japan
3
Department of Orthopedic Surgery, University of Tsukuba, Tsukuba, Japan
4
Department of Orthopedic Surgery, St. Marianna University, School of
Medicine, Kawasaki, Japan
5
Department of Orthopedic Surgery, Chiba University, Graduate School of
Medicine, Chiba, Japan

Purpose: Although lateral vertebral translation is associated with inducing curve progression, no study has
analyzed risk factors for lateral slip in residual idiopathic
scoliosis patients. We investigated risk factors for lateralslip in residual adolescent idiopathic scoliosis.
Methods: Forty-two preoperative patients with residual
adolescent idiopathic scoliosis with thoracolumbar/lumbar (TL/L) curves were included (three males, 39 females;age, 41.9±18.2 years; TL/L Cobb angle, 55.5°±10.0°). All
patients were older than 20 years and had been diagnosed
with AIS during their adolescence. Lateral slip was defined as more than a 6 mm slip on coronal computed tomography images.
Results: Patients were divided into slip (n=22) and nonslip (n=20) groups. There were significant differences inage, TL/L Cobb angle, apical vertebral rotation, apicalvertebral translation, and L3 and L4 tilt between slip andnon-slip groups. Multivariate analyses and receiver-operating characteristic curves demonstrated that only older
age was a significant risk factor for lateral slip (odds ratio,
1.203; 95% confidence interval, 1.067–1.357; p=0.003),
with a cutoff value of 37 years old.
Conclusions: This study demonstrated that older age,especially age >37 years, is a risk factor for lateral slip inresidual adolescent idiopathic patients. These findings
suggest that residual adolescent idiopathic scoliosis patients who need surgery should have surgery by age 37 toprevent lateral slip causing progression.

Department of Pediatric Orthopedic Surgery, Jichi Children’s Medical Center,
Shimotsuke, Japan

Purpose: To assess the effectiveness and predictive factors
for nighttime bracing treatment in adolescent idiopathic
scoliosis (AIS).
Methods: We retrospectively analyzed consecutive patients with AIS treated with the nighttime bracing between February 2006 to December 2018. A cohort of 172
AIS girls 10 years or more who have completed the nighttime bracing treatment with a minimum of 2-year followup were included in this study. Patients were instructed towear the brace only in the nighttime. Curve progression of≤5° was used to define the success of the treatment whilecurve progression of ≥6° and patients underwent surgery
were defined the failure. The success group and the failuregroup were compared in terms of initial age, age of menstruation, initial Risser sign, status of the triradiate cartilage, degree of rotation of the apical vertebra (Nash-Moe
classification), curve pattern, initial curve magnitude, andinitial correction rate (ICR). We used multiple logistic regression analysis to determine the independent predictorsof the treatment outcome.
Results: The mean follow-up period was 55.2±25.6
months. Of 172 patients, 23 patients (13.3%) underwent
surgery due to progression of the curve and the rate oftreatment success was 52.9% among all patients. At the
beginning of this brace treatment, the mean age of thecohort was 12.5±1.4 years, and the mean curve magnitude was 29.4°±7.8°. Compared with the success group,
the failure group was found to have significantly younger
initial age (odds ratio [OR], 0.37; 95% confidence interval[CI], 0.25 to 0.54), older age of menstruation (OR,1.65;
95% CI, 1.16 to 2.34), higher apex of the curve (OR,0.52;
95% CI, 0.29 to 0.96), greater initial curve magnitude(OR,1.06; 95% CI, 1.01 to 1.12), and lower ICR (OR,0.95;
95% CI, 0.90 to 0.99), whereas initial Risser sign, status of
the triradiate cartilage, and Nash-Moe classification were
not associated with success or failure.
Conclusions: In this study, nighttime bracing was effective

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Asian Spine J 2021;15(Supplement 1):S1-S177

for more than half of AIS patients. Initial age, age of menstruation, curve pattern, initial curve magnitude, and ICR
were considered to be significantly associated with thisbracing treatment outcome.

PS-FP-5-89

Predictors for Total Blood Loss During Posterior
Spinal Fusion Surgery for Idiopathic Scoliosis
Eiki Shirasawa, Wataru Saito, Masayuki Miyagi,
Yusuke Mimura, Shinsuke Ikeda, Yuji Yokozeki,
Akiyoshi Kuroda, Takayuki Imura, Toshiyuki Nakazawa,
Gen Inoue, Masashi Takaso
Department of Orthopaedic Surgery, Kitasato University School of Medicine,
Sagamihara, Japan

Purpose: Some previous studies have reported predictive
factors and formulas for perioperative risk factors associated with intraoperative blood loss during correction surgery for idiopathic scoliosis. However, previously reported
formulas are relatively complicated and have limitations.
The purpose of this study was to determine preoperativeand surgical factors associated with intraoperative blood
loss in patients and build a simple predictive formula for
total blood loss.
Methods: Idiopathic scoliosis patients who underwent
posterior spinal fusion from 2017 to 2019 were included.
Preoperative patients’ general data, radiographic parameters, and intraoperative data were collected retrospectively
from medical records. Multiple regression analysis was
performed to generate a predictive formula for blood loss
using preoperative and intraoperative factors as explanatory variables.
Results: Thirty-five patients (average age, 17.2 years) were
evaluated. Average values for operation time and total
blood loss were 280.6 minutes and 738.5 mL, respectively.
The average postoperative Cobb angle and correction rate
were 16.0°and 73.2%, respectively. Using multiple regression analysis, preoperative Cobb angle, number of fixed
vertebrae, and blood loss during exposure were identified
as significant contributing factors. A predictive formula
to estimate total blood loss was calculated: total blood
loss (mL)=−960.3+12.1×activated partial thromboplastic
time+10.5×preoperative Cobb angle (°)+54.6×numberof fixed vertebrae+1.7×blood loss during exposure (mL)

(p<0.05, adjusted R2=0.59).
Conclusions: Preoperative Cobb angle, number of fixed
vertebrae, and blood loss during exposure were the key
factors to estimate total blood loss during posterior spinal
fusion.

PS-FP-5-91

Analgesic and Opioid Medication Profile ofEuropean Adult Spinal Deformity Patients:
Minimum 5 Years Follow-up Study
Caglar Yilgor1, Altug Yucekul1, Tais Zulemyan2,
Yasemin Yavuz3, Anouar Bourghli4, Louis Boissiere5,
Ibrahim Obeid5, Javier Pizones6, Frank Kleinstueck7,
Fransisco J. S. Perez-Grueso6, Ferran Pellisé8,
Ahmet Alanay1, European Spine Study Group9
1

Department of Orthopaedics and Traumatology, Acibadem Mehmet Ali
Aydinlar University School of Medicine, Istanbul, Turkey
2Comprehensive Spine Center, Acibadem University Maslak Hospital,
Istanbul, Turkey
3
Department of Biostatistics, Ankara University Faculty of Medicine, Ankara,
Turkey4
Orthopedic and Spinal Surgery Department, Kingdom Hospital, Riyadh,
Saudi Arabia
5
Spine Unit 1, Bordeaux University Hospital, Bordeaux, France
6
Spine Surgery Unit, Hospital Universitario La Paz, Madrid, Spain
7
Spine Center, Schulthess Klinik, Zurich, Switzerland
8
Spine Surgery Unit, Hospital Universitario Vall d’Hebron, Barcelona, Spain
9
Vall d’Hebron Institute of Research, Barcelona, Spain

Purpose: There remains significant variability in the useof opioids. On one end, it is proven that appropriate pain
control is a critical aspect of patient management; on theother end, past few decades have been associated withmajor increases in overdoses and addiction treatment.
Several studies further noted that preoperative opioid use
resulted in increased hospital length of stay, delayed return to work, greater surgical complications, and adverse
functional outcomes. Nonetheless, patients considering
surgery often expect to discontinue opioids after surgery.
Moreover, most studies have focused on the opioid use
for chronic back pain and degenerative conditions and information regarding long-term opioid use following adultspinal deformity surgery is limited.
Methods: Retrospective analysis of a prospective multicentric data. Adult spinal deformity patients with ≥4-level
fusion and ≥5 years follow-up were included. Analgesic
use was divided into four groups: (1) no analgesics, (2)Asian Spine Journal
non-opioid analgesics (groups 1 and 2 referred as opioid
naive), (3) weak opioids, and (4) strong opioids (groups 3
and 4 referred as opioids). Clinically-relevant six scenarios
were investigated: (1) opioid use preoperatively, (2) opioid
use at 6 weeks, (3) continued opioid use at 6 months onwards, (4) opioid cessation, 5) restart on opioids, and (6)persistent opioid use at 5 years onwards.
Results: A total of 265 patients (215 females, 50 males;mean age, 52±19 years) with a mean follow-up of 67
months (range, 60–102 months) were included. A total of
202 patients (76%) were opioid naive while 63 reported
preoperative opioid use. At 6 weeks, 22.8% of opioid naive
patients were using opioids, which dropped to 13.4% at 6
months onwards. Patients (25%) of who used opioids at 6
weeks eventually discontinued opioids. Follow-up restart
rate on opioids for all opioid naive patients were 42%. At
the final follow-up, 15.4% of opioid-naive patients werestill using opioids. On the other hand, for the 63 patientswith reported preoperative use, opioid usage rate at 6
weeks and at 6 months onwards were 67% and 43%, respectively. An overall cessation rate of 36.5% followed bya restart rate of 44% resulted in a 44.4% of final follow-up
use where >50% of the patients were using stronger opioids.
Conclusions: Approximately 15% of patients who used no
preoperative opioids ended up using long-term opioids.
Plus, another 17% was still using non-opioid analgesics
at a minimum of 5 years postoperative. Of the preoperative opioid users, only 55% could quit opioids, and 57%of the long-term continued users used stronger opioids
compared to preoperative. Patients should be informed
to have realistic expectations regarding opioid use when
considering surgery.

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PS-FP-5-92

Relationship between Adult Spinal Deformity
Surgery and Employment, Sick Leaves, Return
to Work and Early Retirement: Minimum
5-Year Follow-up Study
Caglar Yilgor1, Altug Yucekul1, Tais Zulemyan2,
Yasemin Yavuz3, Javier Pizones4, Ibrahim Obeid5,
Frank Kleinstueck6, Fransisco J. S. Perez-Grueso4,
Ferran Pellisé7, Ahmet Alanay1,
European Spine Study Group8
1

Department of Orthopaedics and Traumatology, Acibadem University
School of Medicine, Istanbul, Turkey
2Comprehensive Spine Center, Acibadem University Maslak Hospital,
Istanbul, Turkey
3
Department of Biostatistics, Ankara University Faculty of Medicine, Ankara,
Turkey4Spine Surgery Unit, Hospital Universitario La Paz, Madrid, Spain
5
Spine Unit 1, Bordeaux University Hospital, Bordeaux, France
6
Spine Center, Schulthess Klinik, Zurich, Switzerland
7
Spine Surgery Unit, Hospital Universitario Vall d’Hebron, Barcelona, Spain
8
Vall d’Hebron Institute of Research, Barcelona, Spain

Purpose: Adult spinal deformity is a common cause of
disability and sick leave. It is unclear whether patients
who undergo surgery can keep an active employment life
as the general population. Although this presents an economic burden to the individual and the society, predictors of permanent disability and early retirement amongindividuals with spinal deformity are not well established.
Information regarding long-term work status following
adult spinal deformity surgery is limited.
Methods: Retrospective analysis of a prospective multicentric data. Adult spinal deformity patients with ≥4-level
fusion and ≥5-year follow-up were included. Work status
was divided into four groups: (1) employed, 2) employed
but at sick leave (groups 1 and 2 referred to as active worklife), (3) unemployed, and (4) retired due to back pain
(groups 3 and 4 referred to as inactive work life). Clinically-relevant six scenarios were investigated: (1) preoperative work status, (2) time it took active ones to return towork, (3) active ones that kept being on sick leave or had
to quit their jobs, (4) active ones that had an early retirement, (5) inactive ones that could make it back to workor became employed, and (6) inactive ones that couldn’t
make it back to work.
Results: A total of 120 patients (92 females, 28 males;mean age, 44.6±14.1 years) with a mean follow-up of 68

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Asian Spine J 2021;15(Supplement 1):S1-S177

months (range, 60–102 months) were included. A total of
74 patients (62%) were active while 46 reported being unemployed or retired early. Of the 46 that were employed,
39 (85%) returned to work within 6 months. At the final
follow-up, 7% became unemployed and 26% had an early
retirement (mean age at surgery, 49.5 years). Of the 28
that were at sick leave preoperatively, 17 (61%) nevermade it back to work; and it took longer for the ones that
did. Patients (39%) had an early retirement (mean age atsurgery, 53.2 yeas). Of the 17 (mean age, 42.5 years) thatwere unemployed and 29 (mean age, 50.5 years) that wereretired due to back pain, respectively, 29% and 24% madeit back to work.
Conclusions: Approximately 30% of patients that wereinvolved in active work life ended up having an early
retirement due to back pain within 5 years after surgery.
Another 15% had long-lasting sick leaves or became unemployed. Only 25% of patients who were not involved in
active work life were able to make it back to work. Patientsshould be informed to have realistic expectations regarding future work life when considering surgery.

PS-FP-5-93

Complications and Analysis of Risk Factorsof Spinal Surgery in Ankylosing Spondylitis:
Single Center Case Series of 50 Patients
Kushal Ramesh Gohil, Saumyajit Basu
Department of Spine Surgery, Kothari Medical Center, Kolkata, India

Purpose: This Retrospective study (level 3) hypothesizedthat ankylosing spondylitis (AS) patients have increased
perioperative morbidity and mortality. AS is an inflammatory disorder which frequently affects spine and known tohave a high percentage of complications including mortality.
Methods: A total of 50 patients of AS (40 males, 10 females; mean age, 54.6 years [range, 22–73 years]; meanfollow-up, 36 months [range, 9–122 months]) presenting
from 2007 to 2020, requiring surgery were included. The
demographic data, body mass index (BMI), comorbidities, neurological and ambulatory status, surgical details,
and complications were analyzed. A multivariate regression analysis of all predisposing risk factors was done. A
total of 40 patients had fractures/pseudoarthrosis (21/19)

and 10 patients, cervical and/or thoracolumbar kyphotic
deformity (3/10). Total of 45 fractures were seen with fivepatients having fractures at two non-contiguous levels.
Patients underwent spinal fusion for stabilization or deformity correction either with an anterior (ASF), posterior(PSF), or combined approach (APSF).
Results: Most common intraoperative complications were
excessive blood loss (EBL>1,500 mL; 55%), incidental
durotomies (17.5%), and screw pullout (15%). In postoperative period, superficial wound infection (2/40), deep
wound infection (1/40), paralytic ileus (10%), pulmonary
complications (27.5%), cardiac complications (17.5%),
and neurodeficit (12.5%) were also seen. Mortality wasseen in 10% of operated patients in early postoperative
period. Late complications were seen in the form of implant prominence (7.5%), junctional kyphosis (7.5%),
implant failure (15%), and pseudoarthrosis (10%). The
length of intensive care unit stay, overall hospital stays,
and rate of blood transfusion were significantly higher inpatients undergoing APSF and PSF as compared to ASF(p<0.05). Patients’ age more than 60 years (p=0.0349),
higher BMI (p=0.0459), paraparesis (p=0.0193), quadriparesis (p=0.0138), and non ambulatory status (p=0.0014)
had more complications. Patients with diabetes andhypertension showed a trend towards more complications. Ambulatory patients had significantly less complications (p=0.0145). Also increasing fusion segments(>9) (p=0.0175), operating time (p=0.0329), and EBL(p=0.0017) were associated with more complications.
Conclusions: AS has high complications during preoperative, intraoperative, and postoperative periods. This single
center retrospective study was done to assess the rates ofcomplications of spinal surgery and the risk factors in AS.
AS has high complications during preoperative, intraoperative, and postoperative periods with 10% mortality
rate. Patients’ age more than 60 years, higher BMI, osteoporosis, presence of major neurodeficit and non ambulatory status, increasing fusion segments (>9), operatingtime and EBL were associated with more complications.
Although AS has high rate of perioperative and delayedcomplications, a thorough preoperative evaluation withextreme caution during positioning, surgery and postoperative period leads to optimal outcome

Asian Spine Journal
PS-FP-5-94

Impact of Endplate Injury during Corrective
Surgery Using Oblique Lumbar Interbody
Fusion in Adult Spinal Deformity
Gen Inoue, Wataru Saito, Masayuki Miyagi,
Takayuki Imura, Eiki Shirasawa, Yusuke Mimura,
Akiyoshi Kuroda, Yuji Yokozeki, Toshiyuki Nakazawa,
Masashi Takaso
Department of Orthopaedic Surgery, Kitasato University School of Medicine,
Sagamihara, Japan

Purpose: These reported oblique lumbar interbody fusion(OLIF) is common as the minimum invasive method for
adult spinal deformity (ASD) surgery, but endplate injury
is induced during the procedure of cage insertion andcorrective maneuver. Still, the site of endplate fracture
and their relationship with subsequent cage subsidence,fusion status or sustained alignment remain unclear. The
purpose of this study is to determine the prevalence andlocation of endplate fracture after inserting a cage for totreat ASD and their association with cage subsidence, fusion status and global alignment.
Methods: We analyzed data obtained by multiplanar computed tomography (CT) of 75 spinal levels in 27 patients(25 females; mean age, 70.3 years old), which was used
to detect endplate fracture immediately after surgery andsubsidence and fusion status at 1 year postoperatively.
OLIF was performed for 2.8±0.4 spinal levels combinedwith posterior spinal fusion for 8.3±0.5 levels. More than
2 mm displacement between CTs was determined as endplate fracture. Additionally, global and local alignment including spinopelvic parameters was evaluated by plain Xray, and postoperative complication was also investigateduntil mean final follow-up of postoperative 3.8 years.
Results: Endplate fracture was observed in 64 levels(85.3%) of 27 patients, with significantly higher prevalence in the posterior area of affected vertebra than in
the anterior area (85.3% vs. 68.0%, p=0.02) in the sagittal
plane. In the coronal plane, there was no significant difference in prevalence between the left (approach) and right(non-approach) sides (77.3% and 81.3%, respectively),or concave and convex sides (69.4% and 79.6%). Compared with preoperative alignment, lumbar lordosis (LL),pelvic incidence–LL, pelvic tilt, sagittal vertical axis, andCobb angle were improved significantly after surgery. No

S99

parameters changed significantly from just after surgery
to the final follow-up. Segmental lordotic and wedging
angles before and after surgery and their changes were notsignificantly different in OLIF segments with or without
endplate fracture. Also, endplate fracture was not significantly associated with neither of cage subsidence, fusion
status, and postoperative complications.
Conclusions: Endplate fracture during an OLIF procedure
is difficult to avoid in ASD corrective surgery. The fracture
is possibly induced by the corrective maneuver, even with
an ideal rod counter and cantilever compressive force.
However, fracture is not significantly associated with subsequent cage subsidence, fusion status, or sustained corrected alignment, even in elderly patients with osteopenia
or osteoporosis.

PS-FP-5-95

Single-Stage Posterior Surgical Treatment for
Grade V Spondylolisthesis of L5 in a Patientwith Neurofibromatosis Type 1 and Dural
Meningocele: A Case Report
Canhua Ye, Chunguang Duan, Huiren Tao
Department of Spine Surgery, Shenzhen University General Hospital,
Shenzhen, China

Purpose: To report the radiological and clinical outcomesof a case treated by single-stage posterior operation withneurofibromatosis type 1 (NF1) and meningocele, while
the surgical treatment for L5/S1 spondylolisthesis of Meyerding grade V remains challenging.
Methods: We present the case of 18-year-old female who
was admitted in our department due to low back pain andradicular pain of both lower limbs 4 months ago. Multiple
cafe-au-lait spots were seen on her back, signifying theneurofibromatosis. The straight leg raising test was negative
and there were no dysesthesias of the legs. Both the muscle
force of lower limbs were normal. X-ray showed the Meyerding grade V spondylolisthesis of L5 (modified Newman
grading 10+10). On the magnetic resonance imaging,dural meningocele could be seen expend through the intervertebral foramen of L4/5, and expend through the firstanterior and dorsal sacral foramen on the left. Considering
it was too risky to perform one stage surgery immediately,
this patient was managed with halo traction for 3 months.

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Asian Spine J 2021;15(Supplement 1):S1-S177

X-ray was rechecked and found there was seldom improvement of the spondylolisthesis comparing to that before
tracking. After a multidisciplinary discussion, we decided
to perform single stage posterior L5 vertebrectomy with
L4/5 and L5/S1 discectomy, sacral dome osteotomy, L2–S1
pedicle screw fixation, and bone graft fusion.
Results: All procedure were performed under the intraoperative neuromonitoring and no signal changes wereseen neither on the motor evoked potentials nor somatosensory evoked potentials. This patient appeared temporary disability of raising legs but recovered 3 days later.
Four days after the surgery, she was able to walk without
radicular pain while wearing the lumbosacral orthosis.
Radiography showed the reduction of L4 and the cage
placed well in the position between L4 and S1. We had toperform debridement of the right iliac side incision because of the complication of poor healing. Before the discharge, she was able to walk without low back pain and noneurological complication were found. At 1.5-year followup, computed tomography scanning showed good bone
fusion. All the pedicle screws are in good position and thecage were not dislocated.
Conclusions: Base on the relative literature, we discuss
about the different choices for treatment of high-gradespondylolisthesis of L5 with NF1 and dural meningocele.

PS-FP-5-96

Handgrip Strength Potentially Predicts Curve
Progression in Adolescent Idiopathic Scoliosis
Girls
Rufina Wing Lum Lau1,2,3, Ka Yee Cheuk2,3,
Vivian Wing Yin Hung4, Fiona Wai Ping Yu4,
Elisa Man Shan Tam2,3, Lyn Lee Ning Wong2,3,4,
Jiajun Zhang2,3, Franco Tsz Fung Cheung2,3,
Wing Sze Yu2,3, Wayne Yuk Wai Lee2,3,Jack Chun Yiu Cheng2,3,4, Tsz Ping Lam2,3,4
1

School of Medical and Health Sciences, Tung Wah College, Hong Kong SAR,
China
2
SH Ho Scoliosis Research Lab, Joint Scoliosis Research Centre of the Chinese
University of Hong Kong and Nanjing University, Hong Kong SAR, China
3
Department of Orthopaedics & Traumatology, The Chinese University ofHong Kong, Hong Kong SAR, China
4
Bone Quality and Health Centre, Department of Orthopaedics andTraumatology, The Chinese University of Hong Kong, Hong Kong SAR, China

Purpose: Adolescent idiopathic scoliosis (AIS) girls are

known to have low bone mass, deranged bone qualities,
low bone mechanical properties, low lean mass, and muscle imbalance. Previous findings from our group showeda unique correlation pattern of handgrip strength andbone qualities in AIS girls as compared to controls. This
longitudinal cohort study aimed to investigate whether
baseline muscle and bone parameters in AIS could predictcurve progression.
Methods: A total of 126 AIS girls aged 12–14 years old
were recruited and followed up until reaching skeletal
maturity. They were divided into progressive and stablegroups according to Scoliosis Research Society criteria.
Maximum handgrip strength at both hands were measured with a standard dynamometer; lean mass at arm,leg, and trunk were measured by bioelectrical impedance
analysis; and bone qualities and bone mechanical properties of non-dominant distal radius were measured byhigh-resolution peripheral quantitative computed tomography. The predictors for curve progression were determined using logistic regression model.
Results: Forty-four AIS (34.9%) had curve progression
with increased Cobb angle ≥6° before skeletal maturity.
Progressive AIS had similar age, curve severity and lifestyle but lower weight, Thumb Ossification Composite
Index, lower trunk (5.7%) and arm lean mass (8.9%),
weaker handgrip strength at dominant side (8.8%), deranged cortical compartment (29.1% smaller area and6.5% lower volumetric bone mineral density), and lower
bone mechanical properties (13.2% lower stiffness and12.5% lower estimated failure load) when compared with
controls. A cut-off of 19.75 kg in maximum dominanthandgrip strength was identified for distinguishing between progressive AIS and stable AIS (75% sensitivity and52.4% specificity; positive likelihood ratio, 1.577; p=0.011)
by receiver operating characteristic analysis.
Conclusions: Progressive AIS showed poorer muscle andbone parameters than stable AIS. A cut-off value of 19.75
kg in the dominant handgrip strength in distinguishingprogressive and stable AIS might potentially be useful for
predicting curve progression in AIS. (This study was supported by RGC of HKSAR [468809 & 468411].)

Asian Spine Journal
PS-FP-5-97

Outcome of Posterior Vertebral Column
Resection in Neglected Rigid Congenital
Scoliosis and Kyphoscoliosis: Our Experienceand Review of Literature
Arif Mohammad, Sattar Abdul, Zahid Mohammad,
Sameer Kabir, Ihsan Ullah, Asmat Ullah
Department of Orthopaedic and Spine Surgery, Hayatabad Medical
Complex, Peshawar, Pakistan

Study Design: Consecutive, retrospective review.
Purpose: Aim of this study is to assess the functional
outcome of posterior vertebral column in patients withneglected congenital kyphosis or kyphoscoliosis.
Overview of Literature: Congenital kyphosis or kyphoscoliosis is rare and progressive deformity which results inserious neurological compromise because of serious spinal cord compression usually at the apex of deformity. In
neglected cases, the patients present with shoulder-trunk
imbalance, coronal and sagittal plane deformity, a rib
hump, pelvic tilt, presence of intramedullary anomalies,
neurological deficit, and VACTERL.
Methods: This single-center retrospective study reviews
the management and outcomes of 37 consecutive patientswith neglected congenital kyphosis and kyphoscoliosis, arigid three-dimensional deformity of the spine treated byposterior column resection by a single posterior approachover a 7-year period (2012–2018). There were 24 males
and 13 females with a mean age of 22 years (range, 12–60
years). Visual Analog Scale score, Oswestry Disability Index, and revised Scoliosis Research Society-22 were used
for assessment of clinical parameter, i.e., pain, function,and self-image evaluation subsequently. Radiological parameters assessment, classification of vertebral anomaly,
pattern and region of curve, preoperative surgical planning, cord compression, and intraspinal anomaly wasevaluated by radiographs, computed tomography scan,and magnetic resonance imaging. Pre- and postoperative
neurology was assessed by the American Spinal Cord Injury Association Scoring. Intraoperative neuromonitoring
was used to assess neurological complications perioperatively. Complications were monitored intraoperatively,
immediate postoperative, and at follow-up.
Results: The average follow-up was 4 years (range, 2–7
years). The preoperative coronal plane deformity was 68°

S101(range, 35°–120°) and corrected to 28° (range, 9°–45°),
showing 64% curve correction. Average preoperative segmental kyphotic angle was 86° (range 3°–110°). Correction rate for kyphosis was 62%. All patients after surgery
showed their baseline neurological status except one withpermeant neurological deficit and other complications
were encountered in five patients. The mean estimatedblood loss was 1,235 mL (range, 800–1,800 mL). The
resection was performed at the involved level and apexof deformity. Fusion was achieved in average 9 segments(range, 4–13 segments). Anterior reconstruction was withtitanium mesh cage in eight and with anterior strut graftin one patient. Bony fusion achieved in all patients, andthere was no correction loss.
Conclusions: Posterior vertebral column resection provides direct circumferential visualization and decompression of the spinal cord through a single posterior approach. Although a difficult procedure it provides better
correction of the deformity in both sagittal and coronalplanes.

PS-FP-5-98

Clinical and Radiological Outcomes in thePatients of Parkinson’s Disease Undergoing
Instrumented Lumbar Spine Surgery for Spinal
Disorders
Ashish Gupta, Saumyajit Basu
Department of Spine Surgery, Kothari Medical Centre, Kolkata, India

Purpose: Parkinson’s disease (PD) patients often develop
stereotypical postural changes. Surgical treatment of spinal disorders is high risk in patients with PD. The aim of
this study was to describe the clinical and radiologicaloutcome in the PD patients operated for spinal disorders.
Methods: A retrospective study included instrumented
surgeries for spinal disorders in patients with PD. Clinicaland surgical data including revision surgeries were collected. Assessment of functional outcomes at last followup was done with modified Oswestry Disability Index(ODI) scores and radiological parameters was assessedon anteroposterior and lateral plain X-rays of the spine.
Sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI),lumbar lordosis (LL), and PI–LL mismatch were measured.

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Asian Spine J 2021;15(Supplement 1):S1-S177

Results: Fourteen PD patients (seven females and sevenmales) with mean age of 64.14 years (range, 47–77 years)
was recruited. Median follow-up was 13.63 months (range,
1–60 months). Nine patients (64.28%) had at least one
associated medical comorbidity along with PD. One patient (7.14%) presented with the sequels of failed previous
surgery. Eleven patients (78.57%) underwent open fixation, and three patients (21.43%) underwent percutaneous
fixation. At a mean follow-up of 13.63 months, we noted
surgical complications in four patients (28.57%): two in theform of adjacent segment degeneration and two proximal
junctional kyphosis. The mean PI–LL mismatch was 19.78°(range, 4°–34°) preoperatively, which marginally improved
to 16.41° (range, 5°–35°) postoperatively, and 15.32° (range,
4°–27°) at final follow-up. The PI–LL mismatch was within
normal limits (0–100) in four patients (28.57%), moderate(100–200) in five patients (35.71%), and marked (200–300)
in five patients (35.71%). All the four patients who havepostoperative complications during follow up had marked
PI–LL mismatch. The rate of surgical revision was 14.29%(two patients)—both had adjacent segment degeneration. Two patients are under observation with proximal
junctional kyphosis. Modified ODI score was minimal disability (0–20) in 4 (28.57%) patients, moderate disability(21–40) in 8 (57.14%) patients, and severe disability (41–60)
in 1 (7.14%) patient; crippled (61–80) in 1 (7.14%) patientand no patient was bed bound.
Conclusions: Patients with PD undergoing lumbar decompression and fusion have higher complication rates.
Preoperative PI–LL mismatch long segment fusion mightlead to poorer outcomes.

PS-FP-5-99

Evaluating Biomechanics of the Novel Active
Apex Correction Technique Using a PatientSpecific Finite Element Approach with
6-Month Follow-up
Daksh Jayaswal1, Alaaeldin Ahmad1,2, Aakash Agarwal3,
Manoj Kodigudla1, Amey Kelkar1, Vijay Goel1
1

University of Toledo, Toledo, OH, USA
Department of Orthopedics, An-Najah Medical School, Nablus, Palestine3
Spinal Balance Inc., Swanton, OH, USA
2

Purpose: Multiple studies have previously highlighted

the shortcomings of both SHILLA & growing rods techniques; the SHILLA suffer a loss of correction or reappearance of deformity through crank-shafting or addingon and growing rods require multiple re-operation. Newer
techniques like the active apex correction (APC) provide
an excellent surgical alternate; designed to avoid apicalfusion amongst having other benefits. The objective is tosimulate and explore the effect of apical remodulation using the APC technique over a 6-month follow-up period
for two patient-specific finite element models.
Methods: Four representative scoliotic models weredeveloped to match patient anteroposterior and lateralradiographs provided by the surgeon. To simulate the
APC technique; the apex was pushed medially followedby compression of the convex side of apex (using twoscrews implanted proximal and distal to the most wedged
vertebrae). The rest of construct was then completed tosimulate the APC. The models then simulated the effectof gravity followed by epiphyseal spinal growth. Relevant
clinical output parameters such as primary Cobb, apicalvertebra translation (AVT), vertebral wedging, and soforth were recorded and compared with the clinical data.
Results: All patients showed a significant reduction in
the Cobb angle (26%, 59%, respectively) for the primary
curve following the APC surgery. The AVT was significantly reduced with the surgical correction. Additionally,
the vertebral wedging in the apical region was significantly reduced due to the APC technique for all patients.
Kyphotic angles (T4–T12) were also reduced in all cases.
Furthermore, at the gravity loading and 6-month spinal
growth time points, the output parameters showed aconsistent maintenance of the correction achieved by the
APC technique (reduction in the Cobb angle, vertebral
wedging and translation) for all patients.
Conclusions: The output parameters indicate excellent
preliminary clinical outcomes. While this study is limited
in terms of follow-up time as well as sample size, it paves
the way for additional research expanding the preliminary
results to get a broader biomechanical understanding of
the APC. The results also indicate the potential of thisnovel technique as a legitimate alternative; it can be employed as-is or in hybrid with incumbent techniques for
effective, innovative patient management.

Asian Spine Journal
PS-FP-5-100

Usefulness of Percutaneous Pedicle Screws for
Minimizing the Risk of Proximal Junctional
Kyphosis after Adult Spinal Deformity
Correction Surgery
Tomohisa Harada1, Sei Terayama2, Yasuo Ohori3,
Satoshi Makio1, Hidenobu Ishibashi4, Ryota Takatori5,
Kenji Takahashi51Spine Center, Rakuwakai Marutamachi Hospital, Kyoto, Japan
Department of Orthopaedics, Shunyoukai Central Hospital, Kimotsuki,
Japan
3
Department of Spine Surgery, Sangubashi Spine Surgery Hospital, Shibuya,
Japan
4
Department of Orthopaedics, Ayabe City Hospital, Ayabe, Japan
5
Department of Orthopaedics, Graduate School of Medical Science, Kyoto
Prefectural University of Medicine, Kyoto, Japan
2

Purpose: The high incidence of postoperative proximal
junctional kyphosis (PJK) is a problem in corrective fusion for adult spinal deformity (ASD). We examined PJK
incidence in two operative procedures and the usefulnessof percutaneous pedicle screws (PPS).
Methods: Corrective fusion was performed on 70 ASD
patients, with follow-up of over 2 years. The basic procedure was lumbar spine lateral interbody fusion, followedby posterior fusion from the lower thoracic spine to thepelvis using PPS. Patients were divided into two groups:
a Hybrid group (thoracic spine: open, lumbar spine: PPS;
30 cases; four males, 26 females; mean age, 76 years), andan All-PPS group (40 cases; one male, 39 females; meanage, 72 years). Fusion levels, operative time, surgical blood
loss, pre- and postoperative radiographic parameters, and
PJK incidence were examined in both groups.
Results: In the Hybrid group, a mean of 10.0 levels was
fused. Mean operative time was 432 minutes, with mean
surgical blood loss of 394 mL. Pre- and postoperative coronal Cobb angles in degenerative lumbar scoliosis were
29º and 8º, respectively, lumbar lordosis (LL) angle wascorrected from 2º to 44º, pelvic incidence (PI)–LL mismatch decreased from 51º to 7º, sagittal vertical axis (SVA)
decreased from 123 to 18 mm, and pelvic tilt (PT) was
corrected from 38º to 24º. In the All-PPS group, a mean of
8.1 levels were fused. Mean operative time was 401 minutes, with mean surgical blood loss of 502 mL. Pre- andpostoperative coronal Cobb angles in degenerative lumbar
scoliosis were 48º and 12º, respectively, LL angle was corrected from 7º to 50º, PI–LL mismatch decreased fromS103

44º to 0º, SVA decreased from 144 to 11 mm, and PT was
corrected from 34º to 18º. PJK incidence was 40% (12 cases/30 cases) in the Hybrid group and 10% (four cases/40
cases) in the All-PPS group, which was significantly lower(p<0.05; by Fisher’s exact test).
Conclusions: In recent years, corrective fixation with PPS
has been used for ASD. One advantage of PPS is low invasiveness, which minimizes intraoperative blood loss, but
this study suggests that using PPS also effectively prevents
postoperative PJK. This is because using PPS preservesmuscle attachments and thus minimizes muscle degeneration, does not interfere with blood flow to posterior supporting tissues, and completely preserves the facet joints
adjacent to the fixed end. In ASD corrective surgery, PPS
was considered to be effective in preventing PJK.

PS-FP-5-103

Optimal Position to Insert the Sacral-AlarIliac Screw with the Analysis of Computed
Tomography View and the Torque of Inserting It
Fumihiro Miyaguchi
Imakiire General Hospital

The purpose of this study was to evaluate the fixing
strength of the modified sacral-alar-iliac (SAI) screwcompared with the SAI screw and the iliac screw. We examined 71 cases of the pelvic computed tomography image. The cases include 31 male and 40 female patients. The
average age was 66.8 years old. The average length of themodified SAI screw was 112.6 mm. The average distance
between the lamina of the sacrum and the most stenosis
point on the quadrilateral surface was 66.8 mm. The average valgus angle when inserting the modified SAI screw
was 28.8°. Our modified SAI screw is gotten the inserting
torque of 7.8 Nm when its screw is set on the quadrilateralsurface, stronger than the SAI screw’s inserting torqueof 3.5 Nm when penetrating the ilio-sacral joint. We canconnect directly the Modified SAI screw with the rod of
pedicle screw without a connecter, but cannot connect
directly the SAI screw or the iliac screw with it. The moststenosis inserting point of the modified SAI screw is on
the quadrilateral surface. And maximum inserting torqueis when penetrating here. The modified SAI screw is useful for spinopelvic fusion.

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Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-5-106

Is It Really Less Invasive?: Systemic Effectsof Anterior-Posterior Lumbar Surgery with
Oblique Lateral Interbody Fusion by Nutrition
Support Team Perspective
Momo Irie, Muneaki Masuda, Osamu Kawano,Takeshi Maeda
Spinal Injuries Center, Fukuoka, Japan

Purpose: Recently, lateral lumbar interbody fusion (LIF)
using oblique lateral interbody fusion (OLIF) is increasing
new procedure, due to its minimal invasiveness. We examined the systemic effects of anterior-posterior lumbar
surgery with OLIF from the perspective of the nutrition
support team.
Methods: The subjects were patients with anterior-posterior lumbar spine surgery with OLIF, which was performed
at our institute from 2016. Out of all 18 cases, in principle,
in addition to anterior fixation of two or more vertebral
bodies, nine cases with one-stage or two-stage posterior
surgery were extracted, and perioperative serum albumin,
total cholesterol, and total lymphocyte count were extracted. The fluctuation of hemoglobin value was examined.
As a method for evaluating nutritional status, a Controlling Nutritional Status (CONUT) score was calculatedusing the former three items. As a control group, the sameevaluation was performed on nine patients who underwent interbody fusion (transforaminal lumbar interbody
fusion [TLIF]) between two or more vertebral bodies byposterior single surgery at the same time, and a statistical
study was conducted between these two groups.
Results: Average serum albumin was 4.3 mg/dL before
surgery for in both armies, 3.4 mg/dL in the OLIF postsurgery, 3.1 mg/dL in the TLIF, and total cholesterolin OLIF-preoperative (pre) 205, TLIF-pre 203, OLIFpostoperative (post) 165, TLIF-post 160, total lymphocyte
counts in OLIF-pre 1,666, TLIF-pre 2,360, OLIF-post
1,325, TLIF-post 1,801, the hemoglobin (Hb) in OLIF-pre
13.3, TLIF-pre 13.8, OLIF-post 11.3, TLIF-post 9.7, the
CONUT scores OLIF-pre 0.67, TLIF-pre 0.33, OLIF-post
3.8, and TLIF-post 3.6. No statistically significant difference was found between the two groups in all items.
Conclusions: OLIF combined surgery is considered to be aminimally invasive surgical method from the viewpoint of
reducing the amount of bleeding and soft-tissue damage. In

fact, in this study as well, the postoperative Hb level tended
to decrease less in the OLIF group. On the other hand, fromthe nutritional point of view, both OLIF and TLIF showed
the same degree of deterioration in nutritional status after
surgery, and it was considered that there was no significant
difference in systemic effects between the two groups. We
investigated the systemic effects of anterior-posterior lumbar surgery with OLIF from a nutritional point of view. It
was considered that the same systemic effects as the conventional procedure were occurring.

PS-FP-5-108

Distribution of Spinal Sagittal Alignment
Based on Hierarchical Clustering
Yusuke Hori1, Hiromitsu Toyoda1, Shinji Takahashi1,
Masatoshi Hoshino1, Shoichiro Ohyama1, Hidetomi Terai1,
Akinobu Suzuki1, Tadao Tsujio2, Sho Dohzono3,
Minori Kato4, Akira Matsumura4, Takashi Namikawa4,
Kazuhide Inage5, Sumihisa Orita5, Masayuki Miyagi6,
Gen Inoue6, Seiji Ohtori5, Masashi Takaso6,
Hiroaki Nakamura1
1

Department of Orthopaedic Surgery, Osaka City University, Osaka, Japan
Department of Orthopaedic Surgery, Shiraniwa Hospital, Ikoma, Japan3
Department of Orthopaedic Surgery, Yodogawa Christian Hospital, Osaka,Japan
4
Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka,Japan
5
Department of Orthopaedic Surgery, Chiba University, Chiba, Japan
6
Department of Orthopaedic Surgery, Kitasato University, Tokyo, Japan
2

Purpose: Spinal sagittal alignment depends on the individual. Although several classifications have been proposed,
the validity remains unclear. The purpose of this study is
to classify and characterize the spinal sagittal alignmentby cluster analysis.
Methods: A total of 1,378 patients (70.4±10.9 years; 680
males, 698 females) who visited a spinal outpatient clinic
were included. Cluster analysis was performed using five
radiographic parameters (thoracic kyphosis [TK], thoracolumbar kyphosis [TLK], lumbar lordosis [LL], pelvic
incidence [PI], and pelvic tilt [PT]) to investigate thecharacteristics of each cluster.
Results: Patients were classified into eight clusters (Ato H). Cluster A (10%) had low PI and large TK (TK41,
TLK26, LL44, PI43, PT6°), cluster B (23%) had low PI and
LL (TK25, TLK19, LL34, PI39, PT14°), cluster C (24%)

Asian Spine Journal
had middle PI and LL (TK22, TLK5, LL44, PI48, PT16°),cluster D (13%) had high PI and LL (TK35, TLK7, LL58,
PI58, PT18°), and none of them had PI–LL mismatch. The
other four clusters had PI–LL mismatches, cluster E (12%)
had a high PI and retroverted PT (TK19, TLK-0.5, LL37,
PI60, PT29°), cluster F (5%) had a low PI and flat back
(TK9, TLK5, LL18, PI42, PT22°), cluster G (4%) had alumbar acute kyphosis (TK10, TLK30, LL-2, PI46, PT34°),
and cluster H (10%) had global kyphosis (TK41, TLK47,
LL24, PI48, PT31°).
Conclusions: The spinal sagittal alignment of 1,378 patients were classified into eight clusters. The four clusters
without PI–LL mismatch were similar to Roussouly’sclassification. The four clusters with PI–LL mismatch included retroverted type, flat back, lumbar acute kyphosis,
and global kyphosis.

PS-FP-5-109

The Analysis of Progression of the Pfirrmann’s
Grade in Distal Unfused Segments in
Postoperative Adolescent Idiopathic Scoliosis:
A Long-Term Follow-up Magnetic ResonanceImaging Based Study
Guna K. Pratheep, Sri Vijay Anand,Rajasekaran Shanmuganathan, Ajoy Prasad Shetty,
Rishi Mugesh Kanna
Division of Spine Surgery, Department of Orthopaedics, Ganga Medical
Centre and Hospital, Coimbatore, India

Purpose: The impact of the long-segment fusions on the
distal mobile segments is of major concern. There is currently a paucity of literature on the progression of Pfirrmann’s grading in distal unfused segments in patientswith strategic pedicle screw instrumentation. In our institute, we conducted a retrospective study to analyze theprogression of the Pfirrmann’s grade in the distal un-fused
lumbar segments in postoperative adolescent idiopathic
scoliosis (AIS).
Methods: A total of 58 patients who underwent surgery
for AIS with minimum 6.5-year follow-up (6.5–15) were
included. Coronal Cobb’s angle (CCA), apical translation, lower instrumented vertebra tilt (LIV tilt), lower
instrumented vertebra-sacral angle (LIV-sacral angle),sagittal spinal parameters (thoracic kyphosis and lumbar

S105

lordosis), and pelvic parameters were measured. Dischealth was assessed in magnetic resonance imaging (MRI)
by Pfirrmann’s grading, total endplate score (TEPS), andfacet degeneration were measured by Fujiwara’s grading.
Functional evaluation was performed using the Scoliosis
Research Society-22 score.
Results: A total of 58 patients were included in the study.
The mean follow-up was 9.1 years. Based on MRI scan,
43 were included in Pfirrmann’s grade static (PGS) groupand 15 in Pfirrmann’s grade progressed (PGP) group. Of
the15 in PGP group, LIV was L4 in eight, L3 in three, L1
in three, and L2 in one. Fifteen patients in our cohort hada progression of Pfirrmann’s grade. Of these, 11 patients(73.3%) progressed from grade 1 to grade 2, but in four
patients (26.6%), Pfirrmann’s grade progressed to morethan 3. The progression of the degeneration did not correlate to the preoperative and postoperative TEPS score,
coronal, or sagittal parameters.
Conclusions: The analysis of progression of the Pfirrmann’s grade in distal unfused segments did not correlatewith preoperative and postoperative coronal or sagittal
parameters and the number of unfused segments.

PS-FP-5-110

Characteristics of Pedicle Screw Misplacement
Using Freehand Technique in Degenerative
Scoliosis Surgery
Tomohiro Yamada, Tomohiko Hasegawa, Yu Yamato,
Go Yoshida, Tomohiro Banno, Hideyuki Arima,
Shin Oe, Yuki Mihara, Hiroki Ushirozako, Koichiro Ide,
Yuh Watanabe, Keiichi Nakai, Kenta Kurosu,
Yukihiro Matsuyama
Department of Orthopedic Surgery, Hamamatsu University School of
Medicine, Hamamatsu, Japan

Purpose: Clinical evidence demonstrating the characteristics of pedicle screw (PS) misplacement with a freehand
technique in degenerative scoliosis (DS) surgery is limited
because previous studies on PS accuracy included several
etiologies. This study aimed to estimate the accuracy of PS
placement in the thoracic to lumbar spine in DS surgery,characterize a patient population with PS misplacement,
and analyze the association between misplaced PS vector
and lumbar coronal curve.

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Asian Spine J 2021;15(Supplement 1):S1-S177

Methods: We retrospectively identified 122 patients (average age, 68.6 years) who underwent corrective anddecompression surgery at a single institution from 2016
to 2019. We extracted patient demographic data, including lumbar coronal curve, a vertebral rotation that could
affect PS misplacement, and evaluated PS accuracy in thethoracic to lumbar spine. We also identified characteristics
of misplacement for each patient. Screw positions werecategorized into grade A, entirely in the pedicle; grade B,<2 mm breach; grade C, 2–4 mm breach; and grade D, >4mm breach using postoperative computed tomography.
Results: The mean preoperative lumbar coronal curvewas 32.3°±18.4°, and the number of fused vertebrae was
8.9±2.8. A total of 2,032 PS were categorized as follows:
grade A, 1,897 PS (93.3%); grade B, 67 PS (3.3%); grade C,
26 PS (1.3%); and grade D, 43 (2.1%). One PS (grade D)
inserted at T5 needed removal surgery due to neurological deficit. The misplacement group (grades C and D) hada significantly stronger lumbar coronal curve and apicalvertebral rotation compared with the accuracy group(grades A and B). Misplaced PS vector (direction and degree) was significantly correlated with inserted vertebra
rotation. Grade D misplacement was distributed mainly
around the transitional vertebra of the lumbar curve.
Conclusions: The obtained findings could help identify thevertebra location at higher risk of PS misplacement using
the freehand technique. The accuracy of PS insertion in thethoracic to lumbar spine was high in DS surgery, but theneed for care was highlighted in the transitional vertebra.

PS-FP-5-113

Increased C7 Tilt Is Associated with Higher
Risk of Shoulder Imbalance in Adolescent
Idiopathic Scoliosis Patients Receiving
Posterior Spinal Fusion
Juiyo Hsu1, Chih-Wei Chen1, Ming-Hsiao Hu1,
Po-Liang Lai2, Shu-Hua Yang1
1

Department of Orthopedic Surgery, National Taiwan University Hospital,
Taipei, Taiwan
2
Department of Orthopedic Surgery, Linkou Chang Gung Memorial
Hospital, Taoyuan, Taiwan

Purpose: Shoulder balance plays a vital role in correction
surgery for adolescent idiopathic scoliosis (AIS). Even
with detailed preoperative evaluation of the patient, shoul-

der imbalance may occur. However, there is a scarcity ofsufficient evidence comparing the various factors in current literatures and there is also a lack of linear prediction
models. This study examines the correlation between theindividual vertebral tilt and shoulder balance, specificallyaims to identify parameters that may serve as an intraoperative proxy in surgical correction of AIS.
Methods: AIS patients with (1) single posterior spinal correction and fusion and (2) all pedicle screws instrumentation with derotation in two tertiary medical centers from2015 to 2018 were recruited for analysis. We excluded
patients who underwent correction over lumbar segments
only (Lenke classification type 5) and patients with scoliosis other than AIS, such as neuromuscular scoliosis andcongenital scoliosis. All patients had a minimum followup of 2 years with a complete set of standing anteroposterior radiographs for whole spine. Both inner and outershoulder balance parameters were included for detailed
analysis, including clavicular angle (CA), coracoid height
difference, clavicular tilt angle difference, clavicle–rib cageintersection difference, and 1st rib tilt. Individual vertebral tilt from C5 to T4, as well as the upper instrumented
vertebra tilt on coronal plane were also recorded for further analysis.
Results: A total of 107 patients of AIS were recruited in
the final analysis. The mean follow-up length was 2.5
years. Mean preoperative Cobb angle for main thoracic
curve was 52.6°±9.8° (range, 36.6°–91.5°), and the postoperative Cobb angle was 20.6°±6.9° (range, 7.2°–39.2°). In
Pearson correlation analysis, C7 tilt demonstrates significantly moderate to high correlation with both inner andouter shoulder balance parameters (coefficient, 0.36–0.72;
p<0.05). In subgroup analysis, postoperative C7 tilt oncoronal plane was identified as an independent risk factor
for developing shoulder imbalance (odds ratio, 1.19; 95%
confidence interval, 1.066–1.329; p=0.0019) in multivariate logistic regression model. In addition, quantification
for change of shoulder balance is established as follows:
ΔCA=0.21×[(ΔC7 tilt+ΔT1 tilt)/2)] (standard error=0.04,
p<0.001).
Conclusions: C7 tilt on coronal plane is highly correlated
to shoulder balance parameters in AIS surgical correction. Furthermore, increased C7 tilt poses a higher risk ofdeveloping shoulder imbalance. More meticulous strategy
to improve shoulder balance is warranting, and quantification of shoulder balance change by individual vertebral
tilt may be adopted in the surgical correction of AIS.

Asian Spine Journal
PS-FP-6-1

Computed Tomography Based Intraoperative
Navigation for Spine Tumors: Perspectives inSurgical Margin
Young-Hoon Kim, Sang-Il Kim, Hun-Chul Kim,
Hyung-Youl Park

S107

local recurrence leads to revisional wide excision and reconstruction.
Conclusions: CT based navigation-assisted surgery for
spinal tumors could be useful not only for accurate reconstruction, but for determination of surgical margin. Even
limited number of cases, both thorough preoperative
radiological review and intraoperative navigation could
provide us more benefits for safe resection margin.

Department of Orthopedic Surgery, Seoul St. Mary’s Hospital, The Catholic
University of Korea, Seoul, Korea

Study Design: A retrospective study.
Purpose: To evaluate efficacy of intraoperative navigation
for spine tumors on effective surgical margin.
Overview of Literature: Computed tomography (CT)based intraoperative navigation is gradually popular inorthopedic surgery. Especially, the use of this system may
be more useful for spinal tumors, not only in the point ofview of reconstruction, but of safe surgical margin.
Methods: A retrospective review was performed in consecutive six patients who underwent CT based navigation assisted surgery for spinal tumors between 2017 to2019. The cases included osteosarcoma (n=3), chondroma(n=1), chordoma (n=1), and solitary breast cancer metastasis (n=1). For surgical margin for tumor excision, thorough review of preoperative radiographic studies including diffusion weighted magnetic resonance images andpositron emission tomography-CT was done with musculoskeletal radiologists. Based on these findings, surgicalmargin was made using intraoperative navigation system.
Clinical data such as general demographics, intraoperative efficacy of this system for reconstruction, perioperative complications, oncologic outcomes and pathologicalreview of surgical margin were collected.
Results: Mean age of the patients was 47 years (range,
16–77 years), and mean duration of follow-up was 12.8
months (range, 5–32 months). There were no intraoperative complications related to intraoperative navigation
system. And in terms of reconstruction, there was no mal
positioned screw or early mechanical failure. In terms of
oncological outcomes, all patients survived with five ofno evidence of disease and one of alive with disease state.
On resection margin, tumor free margin was obtained infive patients and margin involvement of tumor was notedin patient with solitary metastasis. Adjuvant radiotherapy
was done for local control in the patient with margin
involvement. In one patient with sacrum osteosarcoma,

PS-FP-6-2

Spinal Extra-Osseous Chordoma Mimicking
as Herniated Intervertebral Disc in the Lumbar
Spine
Kang Kai Lim1, Zulkefli Atan1, Manoharan Krishnan1,
Mohamad Azhari Omar2, Zulrushdi Md Yusof3
1

Department of Orthopaedic and Traumatology, Hospital Raja Permaisuri
Bainun, Ipoh, Malaysia
2
Department of Neurosurgery, Hospital Raja Permaisuri Bainun, Ipoh,
Malaysia3
Department of Radiology, Hospital Raja Permaisuri Bainun, Ipoh, Malaysia

Most lumbar disc herniation occur between the age of 30
and 50 years old, with a reported average age of 40.8 years.
Age-related changes within the extracellular matrix ofthe intervertebral disc leads to weakening of the annulus
fibrosus, causing susceptibility to annular fissuring andtearing. These changes in the composition of disc matrix
often lead to loss of intervertebral disc height, which inturn predispose the apophyseal joints to osteoarthritis.
Loss of disc height also allow ligamentum flavum tothicken, leading to narrowing of the spinal canal and theconstellation of signs and symptoms of degenerative lumbar spondylosis. We report a case of an 81-year-old malewith clinical presentation of low back pain and gradual leg
weakness. Physical examination and magnetic resonanceimaging findings suggested radiculopathy caused by herniated L3/L4 lumbar intervertebral disc. Preoperative Visual Analog Scale (VAS) was 8/10 and Medical ResearchCouncil (MRC) Scale 3/5 of both lower limbs. Despite significant right paracentral disc extrusion, there was no reduction in disc height and no marked hypointense signal
in T2-weighted images to suggest a degenerated disc. A
suspicion of soft tissue tumor was made and we proceededwith laminectomy, biopsy and L3–L4 short segment instrumentation. Intra-operatively we found a whitish mass

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Asian Spine J 2021;15(Supplement 1):S1-S177

appearing to originate from L3/L4 intervertebral discspace exerting mass effect and causing dural indentation
at this level. There was adherence of this mass to the dura.
Postoperative VAS reduced to 4/10 and improvement of
MRC 4/5 of both lower limbs. Histopathology and immunochemistry showed neoplastic cells with focal nuclear
positivity for brachyury, consistent with chordoma.

PS-FP-6-4

Perioperative Complications of Total En Bloc
Spondylectomy for Spinal Tumors
Satoru Demura1, Satoshi Kato1, Kazuya Shinmura1,
Noriaki Yokogawa1, Takaki Shimizu1, Makoto Handa1,
Ryohei Annen1, Motoya Kobayashi1, Yohei Yamada1,
Hideki Murakami2, Norio Kawahara3, Hiroyuki Tsuchiya1
1

Department of Orthopaedic Surgery, Graduate School of Medical Sciences
Kanazawa University, Kanazawa, Japan2
Department of Orthopaedic Surgery, Nagoya City University, Nagoya, Japan3
Department of Orthopaedic Surgery, Kanazawa Medical University, Kahoku,
Japan

Purpose: We evaluated the perioperative complications
associated with total en bloc spondylectomy (TES) for
spinal tumors depending on the extent and level of tumor
resection.
Methods: We retrospectively reviewed 307 patients who
underwent TES in a single center. The subjects comprised
164 men and 143 women with a mean age of 52.9 years
at the time of surgery. The surgery was performed in 225
patients with spinal metastases, 34 with a primary malignant, 41 with an aggressive benign, and seven with a
primary unknown tumor. The main lesion was located in
the thoracic spine in 213, and lumbar spine in 94 patients.
There were 97 patients who underwent TES for more than
two consecutive vertebrae.
Results: Major and minor perioperative complications
were observed in 122 (39.7%) and 84 (27.4%) patients,
respectively. The breakdown of complications was as follows: bleeding more than 2,000 mL in 60 patients (19.5%),
hardware failure 82 (26.7%), neurologic 46 (15.0%), surgical site infection 23 (7.5%), wound dehiscence 16 (5.2%),
cerebrospinal fluid leakage 45 (14.7%), respiratory 52(16.9%), cardiovascular 11 (3.6%), digestive 19 (6.2%),
and mortality within 2 months 4 (1.3%). The total number of complications per surgery were 1.01±1.0 in single

group and 1.56±1.2 in more than two resection group.
Cardiovascular, respiratory complication, and hardware
failure were statistically higher in more than two resection group. The amount of bleeding in lumbar lesion andrespiratory complication in the thoracic lesion were statistically higher. Multivariate analysis showed combined
approach and more than 2 vertebral resections were significant independent factors.
Conclusions: The characteristics of perioperative complications after TES were different depending on the extent
and level of the tumor resection. In addition to preoperative clinical and pathological factors, it is also important
to consider these factors in cases of en bloc resection for
spinal tumors.

PS-FP-6-6

Long-Term Outcomes of Spinal Meningioma
Resection with Outer Layer of Dura Preservation
TechniqueHirokazu Saiwai1, Seiji Okada2, Mitsumasa Hayashida3,
Katsumi Harimaya4, Yoshihiro Matsumoto1,
Ken-ichi Kawaguchi1, Akinobu Matsushita1,
Kei-ichiro Iida1, Kazu Kobayakawa1, Kazuya Yokota5,
Takeshi Maeda5, Kuniyoshi Tsuchiya6, Takeshi Arizono7,
Taichi Saito8, Kazutoshi Nakaie9, Yukihide Iwamoto10,
Yasuharu Nakashima1
1

Department of Orthopedic Surgery, Graduate School of Medical Sciences,
Kyushu University, Fukuoka, Japan2
Department of Orthopedic Surgery, Graduate School of Medical Sciences,
Osaka University, Osaka, Japan3
Department of Orthopedic Surgery, Saga-Ken Medical Centre Koseikan, Saga,Japan
4
Department of Orthopedic Surgery, Kyushu University Beppu Hospital,
Beppu, Japan
5
Department of Orthopedic Surgery, Spinal Injuries Center, Fukuoka, Japan
6
Department of Orthopedic Surgery, Japan Community Health Care
Organization, Kyushu Hospital, Fukuoka, Japan
7
Department of Orthopedic Surgery, Kyushu Central Hospital, Fukuoka, Japan
8
Department of Orthopedic Surgery, Fukuoka City Hospital, Fukuoka, Japan
9
Department of Orthopedic Surgery, National Hospital Organization,
Fukuoka-Higashi Medical Center, Fukuoka, Japan10
Department of Orthopedic Surgery, Kyushu Rosai Hospital, Fukuoka, Japan

Purpose: Spinal meningioma is a common benign intradural spinal tumor. It has been reported that the local
recurrence rate after surgical resection increases with longer follow-up duration. Simpson grade 1 resection could
reduce the risk of recurrence, but this procedure needs

Asian Spine Journal
dural reconstruction, which would cause cerebrospinal
fluid (CSF) leakage or iatrogenic spinal cord injury. There
has been one report that the dura preservation techniquereduces the risk of CSF leakage, in which the meningioma
together with the inner layer of the dura is removed andthe outer layer is preserved for simple dural closure. The
long-term outcomes with this technique have never been
investigated.
Methods: In this study, we retrospectively analyzed thedata of 38 surgically treated patients (dura preservation
technique, 12 patients; Simpson grade 2 resection, 26
patients) to assess the long-term recurrence rate (mean,
121.5 months; range, 60–228 months).
Results: The local recurrence rate in the dura preservationgroup was 8.3% (one of 12 cases), which was similar tothat in Simpson grade 2 resection group (two of 26 cases[7.7%]).
Conclusions: Although this case series did not indicate
the significant difference in the recurrence rates between
the dura preservation group and Simpson grade 2 group,
we consider that this technique still has advantages for
surgically less invasiveness in terms of dural reconstruction which is necessary for Simpson grade 1 and higher
possibility of complete resection of tumors compared with
Simpson grade 2 resection.

PS-FP-6-7

Prognostic Factors for Short-Term versus
Long-Term Readmission-Free Survival after
Metastatic Spine Tumor Surgery
Naresh Kumar1, Andrew Thomas1, Liang Shen2,Sarah Tang1, Sridharan Ramakrishnan1, Sirisha Madhu1
1National University Health System, Singapore
National University of Singapore, Singapore

2

Purpose: Unplanned hospital readmissions (UHR) after
metastatic spine tumor surgery (MSTS) are important
indicators of poor general condition of the patient, aggressive disease, and inappropriateness of treatment approach. Increase in UHR reduces quality of life (QoL) of
the patient and increases resource utilization. Hence, readmission-free survival (ReAFS) defined as ‘time duration
between discharge after index-operation and first UHR/
death’, may serve as a new outcome indicator in MSTS-pa-

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tients. The aim of our study was to identify the prognostic
factors for short-term (up to 3-months) and long-term (upto 1-year) ReAFS after index-MSTS.
Methods: We retrospectively reviewed the medical recordsof 266 consecutive adult patients who underwent MSTS
between 2005–2016 with follow-up until 2 years or demise, whichever was earlier. Institutional Review Board
approval was obtained prior to study initiation. Demographic, oncological, procedural, and postoperative details
were collected. Factors predictive of short and long-term
ReAFS were evaluated using multivariate analysis.
Results: Final analysis included 209 patients. Mean age
was 60±12 years. Majority had lung primaries (25.8%). A
total of 110 and 57 patients were alive without UHR up
to 3 months and 1 year of index-MSTS, respectively. Bothunivariate and multivariate analysis revealed that patientswith Eastern Cooperative Oncology Group performancestatus (ECOG-PS) 0–2 (multivariate adjusted odds ratio[OR], 0.286; 95% confidence interval [CI], 0.110–0.747;
p=0.011), preoperative hemoglobin >12 g/dL (OR, 0.444;
95% CI, 0.244–0.807; p=0.008), number of comorbidities <4 (OR, 0.474; 95% CI, 0.223–1.008; p=0.052), index
length-of-stay ≤10 days (OR, 0.359; 95% CI, 0.170–0.760;
p=0.007), and no neurological/hematologic complications during index-stay (OR, 0.145; 95% CI, 0.031–0.688;
p=0.015) had higher probability of ReAFS up to 3 months
after MSTS. On univariate analysis, patients with a higher
probability of ReAFS up to 1 year included those with
ECOG 0–2 (p=0.017), preoperative hemoglobin >12(p=0.003), and prostate primaries (p=0.014). Multivariate
analysis revealed preoperative hemoglobin and primarytumor type to be significant factors influencing long-term
ReAFS. Lung primaries had highest UHR/death, whilebreast had the least at 1 year after MSTS.
Conclusions: Our study revealed that general condition of
the patient at the time of index surgery (ECOG and preoperative hemoglobin status) may significantly influence both
short and long-term ReAFS after MSTS. Short-term ReAFS
may also be influenced by the number of comorbidities
and quality of postoperative recovery (length of index stayand postoperative complications during index stay), while
long-term ReAFS may be influenced by the primary tumor
type. Knowledge of factors influencing short-term ReAFS
can allow oncologists and surgeons to optimize treatment
approach, quality of cancer care, and patient counselling/surveillance to prolong the ReAFS, set expectations andimprove the long-term QoL of MSTS-patients.

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PS-FP-6-8

PS-FP-6-10

Clinical Results of Carbon-Ion Radiotherapy
with Separation Surgery for Primary Spine/
Paraspinal Sarcoma

The Surgical Strategies for Dumbbell-Shaped
Tumors of the Upper Cervical Spine

Yoshihiro Matsumoto, Kei-ichiro Iida, Hirokazu Saiwai,
Makoto Endo, Toshifumi Fujiwara, Ken-ichi Kawaguchi,
Yasuharu Nakashima
Department of Orthopaedic Surgery, Kyushu University School of Medicine,
Fukuoka, Japan

Purpose: To evaluate the clinical outcome of combination
carbon-ion radiotherapy with separation surgery (CIRTSS) in patients with primary spinal/paraspinal sarcoma(PSPS) and epidural spinal cord compression (ESCC).
Methods: CIRT-SS was performed in 11 consecutive
patients. Patients treated in the primary and salvage settings were categorized into group A (n=8) and group B(n=3), respectively. Clinical results and imaging findings
were collected, with a particular focus on ESCC grade,
treatment-associated adverse events (AEs), and the locoregional control (LRC) rate and overall survival (OS).
Results: The median follow-up period from the start of
CIRT-SS was 25 months (range, 7–57 months). ESCC
was improved by SS in all cases. No patients exhibitedradiation-induced myelopathy (RIM), but three developed grade 3 vertebral compression fracture (VCF) during follow-up. Locoregional recurrences were observedin four patients (group A: 1 [12.5%], group B: 3 [100%]).
Over the entire follow-up period, three patients developed
distant metastases and two patients died. The 2-year LRC
rate and OS were 70% and 80%, respectively.
Conclusions: CIRT-SS in the primary setting achieved acceptable LRC and OS without RIM in patients with PSPS
with ESCC. VCF was the most frequent AE associatedwith CIRT-SS.

Hao Zhang, Wei Ya Hu
Southern Medical University Affiliated People’s Hospital of LongHua,
Shenzhen, China

Purpose: To investigate the classification, surgical approach and surgical outcome of dumbbell tumors of theupper cervical spine.
Methods: From January 2012 to April 2019, 11 cases ofdumbbell-shaped tumors of upper cervical spine wereanalyzed retrospectively. According to PUTH (Peking
University Third Hospital) classification, there were one
case of type 1, six cases of type 3, three cases of type 5, andone case of type 7.
Results: Among the 11 patients, there were five males andsix females, with an average age of 36.55 years (range,
28–52 years), eight cases were schwannomas, three cases
were meningiomas, and two cases were neurofibromatosis. Six cases were performed tumor resection, five cases
were performed tumors resection and internal fixation.
The average Japanese Orthopaedic Association scorepre- and postoperative was 9.64 (range, 7–12) and 13.09(range, 12–15), respectively. The average operation timewas 312.36 minutes (range, 185–480 minutes) and theaverage bleeding volume was 324.55 mL (range, 130–600mL). Postoperative complications included one case of
infection and three cases of cerebrospinal fluid leakage.
The average follow-up time was 34.73 months (range, 3–76
months). No recurrence occurred.
Conclusions: The key to resect the dumbbell-shaped tumors of upper cervical spine completely is to select themost suitable surgical approach according to the different regions of tumors, so as to maximize the exposure totumors and reduce the risk of surgery. Complete resection of tumors can effectively reduce the recurrence rate.
When excision of the facet joints is needed to expose thetumors, internal fixation is needed to avoid instability ofthe spine after operation. The spinal canal tumors should
be removed first to avoid spinal cord injury to the greatest
extent. Surgery should be performed under a microscope
to ensure a clear vision and facilitate the cooperation andoperation of the surgeon and assistant. Motor evoked potential and somato-sensory evoked potential can reflectAsian Spine Journal
the spinal cord nerve injury in time and should be usedroutinely.

PS-FP-6-11

Surgical Outcomes of Spinal Cord Tumor in
Elderly Patients Using the Japanese Orthopaedic
Association Cervical Myelopathy Evaluation
Questionnaire
Shuhei Ito1,2, Narihito Nagoshi1, Osahiko Tsuji1,
Satoshi Nori1, Satoshi Suzuki1, Eijiro Okada1,
Mitsuru Yagi1, Morio Matsumoto1, Masaya Nakamura1,
Kota Watanabe11Keio University School of Medicine, Orthopaedic surgery, Tokyo, Japan
Department of Orthopaedic Surgery, National Hospital Organization
Tokyo Medical Center, Tokyo, Japan
2

Purpose: There have been few studies to evaluate the impact of age on the surgical outcomes in patients with spinal cord tumor (SCT). The Japanese Orthopaedic Association (JOA) score only assesses the neurologic function,
whereas the Japanese Orthopaedic Association Cervical
Myelopathy Evaluation Questionnaire (JOACMEQ), a
self-administered questionnaire, includes subitems regarding not only extremity and bladder function, but cervicalfunction and quality of life (QOL), which can comprehensively evaluate the outcomes in cervical disorders. The
aim of this study is to clarify the postoperative outcomesin elderly patients aged 65 years or older compared withthose in young patients who underwent surgical resection
for cervical SCT using the JOACMEQ.
Methods: This study includes 97 patients (49 males, 48
females) with cervical SCT who underwent surgical treatment at single institution between 2000 and 2016 andwere followed up for at least 2 years after surgery. The patients were divided into a young group (<65 years, n=65)
and an old group (≥65 years, n=32). The JOA scores andJOACMEQ subitems were compared between the twogroups. Further, clinical outcomes were compared between intramedullary and extramedullary tumors in theelderly patients as subanalysis.
Results: The preoperative JOA score in the old groupversus the young group was 11.3±3.4 versus 14.0±2.2,
respectively (p<0.01). Each baseline parameter in the
JOACMEQ was significantly lower in the old group. In
contrast, the JOA score recovery rate (36.3%±37.8% vs.

S111

33.8%±38.3%) and the JOACMEQ effectiveness rate ineach parameter (cervical spine: 51.9% vs. 60.0%, upper
extremity: 52.2% vs. 36.4%, lower extremity: 39.3% vs.
48.7%, bladder: 34.5% vs. 24.0%, QOL: 36.5% vs. 35.4%)
were comparable between two groups without statisticalsignificance. The comparative analyses of the elderly patients between intramedullary and extramedullary lesions
revealed that the JOA recovery rate and the lower extremity function and QOL of the JOACMEQ effectiveness rate
in intramedullary tumors were significantly worse thanthose in extramedullary tumors.
Conclusions: Although elderly patients with cervicalspinal tumors showed lower preoperative scores than
younger patients, the functional and QOL recovery following surgery was comparable between the two groups.
Therefore, the age at surgery did not adversely affect theclinical outcomes. In contrast, the expected postoperative
course should be cautiously explained to patients withintramedullary tumor prior to surgery, due to the inferior
efficacy compared to the course in extramedullary tumor.

PS-FP-6-12

A Method for Predicting the Location of Dural
Attachment of Spinal Meningioma: Tumor
Attachment Angle
Kazu Kobayakawa1,2, Takeshi Maeda1, Osamu Kawano1,
Hiroaki Sakai1, Muneaki Masuda1, Yuichiro Morishita1,
Tetsuo Hayashi1, Kensuke Kubota1, Kazuya Yokota1,
Hironari Kaneyama1,Hirokazu Saiwai2, Keiichiro Iida2,
Akinobu Matsushita2, Kenichi Kawaguchi2,
Yoshihiro Matsumoto2, Yasuharu Nakashima2
1

Department of Orthopedic Surgery, Spinal Injuries Center, Fukuoka, Japan
Department of Orthopedic Surgery, Kyushu University, Fukuoka, Japan

2

Purpose: Asian Pacific Islander was reported to have thehighest incidence of spinal meningiomas. Spinal meningioma commonly occurs in an intradural-extramedullary
position and sometimes needs resection of the dura withthe tumor, causing cerebrospinal fluid leakage. Previously,
we had developed a surgical procedure without need forresection of the dura mater: combined resection of meningioma and inner layer of the dura (CR-MILD), but
it is difficult to perform CR-MILD in case that the dural
attachment of the tumor is ventral. The surgical proce-

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Asian Spine J 2021;15(Supplement 1):S1-S177

dure should depend on its location of dural attachment,
but there is no objective method to foresee the localization. The objective of this study is to develop a method topredict the location of dural attachment of spinal meningioma.
Methods: We performed a retrospective review of the
medical, radiographic, surgical, and postoperative recordsof patients who underwent resection of spinal meningioma at our institution between 2007 and 2018. Twentyfour patients were included. The relationships between thelocation of dural attachment and surgical procedures, location of tumor, dural tail sign were investigated. Considering that the dural attachment might be located against
spinal cord that was pressed by the tumor, we measured
a point opposite the spinal cord pressed by the tumor.
First, a line connecting two vertices of spinal cord wasmade in an axial plane of gadolinium-enhanced magnetic
resonance imaging. Second, a line parallel to this line wasformed as a tangential line of the spinal canal beside spinal cord. Third, an extension line of the points of tangency
and the center of the spinal canal was made. We assumed
that the attachment of meningioma to the dura might beclose to the intersection of this extension line and spinal
canal. To digitalize the location of this intersection, we
measured an angle between the extension line and medial
line of the vertebra and named it tumor attachment angle(TAA).
Results: The success rate of CR-MILD depended on thelocation of dural attachment of the tumor. Neither thelocation of tumor nor dural tail sign could not exactly
predict the location of dural attachment. However, when
TAA is over 120°, the location of the attachment of spinal
meningioma is dorsal of spinal cord in all patients of thisstudy. The cut-off point of TAA for dorsal attachment was
99°.
Conclusions: TAA predicts the location of dural attachment of spinal meningioma, which helps surgeons to create a preoperative surgical plan.

PS-FP-6-13

Usefulness of Artificial Cerebrospinal Fluid
Replacement in Intradural Surgical Procedure
Muneaki Masuda, Takeshi Maeda, Osamu Kawano
Department of Orthopedic Surgery, Spinal Injuries Center, Fukuoka, Japan

Purpose: In surgical procedure with a dural incision, such
like intradural tumor resection or more, surgeon have to
face the problems with postoperative intracranial hypotension and the risk of rare intracranial hemorrhages. We
examined whether these risks could be reduced by injecting artificial cerebrospinal fluid into the subarachnoid
space at the time of dural suture in intradural surgery.
Methods: From February 2016, a total of 32 patients (15males and 17 females) who had received intradural surgery and underwent postoperative computed tomography (CT) scan were included. The degree of intracranial
emphysematous lesions by postoperative CT, presence orabsence of intracranial hypotension symptoms, and thetime until relief of symptoms were evaluated. From May
2017, artificial cerebrospinal fluid (ArtCereb) refilling wasstarted at dural suture.
Results: Significant improvement of emphysematouschanges and intracranial hypotension symptoms weremarked in the group with artificial cerebrospinal fluid injection. Severe pneumocephalus in postoperative CT scan
had reduced to 33.3% from 72.7% and intracranial hypotension symptom had reduced to 23.8% from 54.5%.
Conclusions: Although subarachnoid space refilling by artificial cerebrospinal fluid is a simple procedure, it seems
to be extremely useful for reducing the risk of postoperative low intracranial pressure and intracranial hemorrhage.

Asian Spine Journal
PS-FP-6-14

The Radiographic Characters and Surgical
Outcomes of Spinal Meningioma Who Grade 1
Tomohiko Hasegawa1, Yu Yamato1, Go Yoshida1,
Sho Kobayashi2, Tatsuya Yasuda3, Tomohiro Banno1,
Hideyuki Arima1, Shin Oe1, Yuki Mihara1,
Hiroki Ushirozako1, Yukihiro Matsuyama1
1

Department of Orthopedics, Hamamatsu University School of Medicine,
Hamamatsu, Japan2
Department of Orhopedics, Hamamatsu Medical Center, Hamamatsu,
Japan
3
Department of Orhopedics, Iwata City Hospital, Iwata, Japan

Purpose: Most spinal meningiomas are benign, but a recurrence rate of about 10% has been reported. Therefore,
in order to know the imaging characteristics of benign
meningioma and the risk factors for recurrence and reoperation, we investigated the imaging characteristics andhistological type, surgical results, and recurrence in World
Health Organization (WHO) grade 1 spinal meningiomas
those were surgically treated in our department.
Methods: Twenty-six cases of WHO grade 1 spinal cord
meningiomas were treated by surgical resection from June2010 to April 2020 in our department. We investigatedspinal level of tumor location, location of axial section,
presence of calcification on computed tomography, presence of dural tail sign on contrast magnetic resonanceimaging, dural treatment method at the time of surgery,histologic type, tumor recurrence, and re-operation inthese cases.
Results: The average age was 62 years (19 females and 7
males). The tumor location level incidence was cervicalspine 38%, cervical thoracic spine 4%, thoracic spine 50%,
and thoracolumbar spine 8%. Tumor locations on theaxial section were ventral 42%, dorsal 12%, right 15%, left
23%, and dumbbell type 8% in the dural sac. Tumor calcification was found in 46% and dural tail sign was found in
85%. In 78%, the dura mater of tumor origin was resected
together with the tumor, in 4% just the inner layer was
resected, and in 18%, only the attachment electric ablation
was performed after the tumor resection. The histological types were meningothelial and transitional in six cases
each, psammomatous in four cases, fibrous in three cases,
and angiomatous and metaplastic in two cases each, andthree cases were difficult to distinguish. Dural tail signs
were found in 100% of psammomatous, angiomatous, andS113

metaplastic, but 67% of meningothelial and fibrous. Calcification was found in 100% of psammomatous, angiomatous, and metaplastic, but 33% in meningothelial andtransitional. Of the 19 patients who could be followed up
for more than 2 years after surgery, recurrence occurredin one patient (4%), and two cases including one recurrent
case and one postoperative cerebrospinal fluid leakage
were performed reoperation. Both cases were dumbbelltype tumor. The preoperative mean McCormick score of
19 cases was 2.5, and the mean at the final observation
was 1.4.
Conclusions: Dural tail sing was found at a high rate in
the imaging findings of WHO grade 1 spinal meningiomas. Dumbbell-type tumors are at risk of cerebrospinal
fluid leakage due to poor dural repair and recurrence due
to poor resection.

PS-FP-6-16

The Utility of Minimal Access and Separation
Surgery in the Management of Metastatic
Spine Disease
Jiong Hao Tan, Andrew Cherian Thomas,
Yong Hao Joel Tan, Hwee Weng Dennis Hey,
Naresh Kumar
Department of Orthopedic Surgery, National University Hospital, Singapore

Purpose: This study compares outcomes of percutaneous pedicle screw fixation (PPSF) to open posterior stabilization (OPS) in patients with spinal instability; andmini-open separation surgery (MOSS) to open posteriorstabilization and decompression (OPSD) in patients withmetastatic spinal cord compression (MSCC).
Methods: We retrospectively analyzed all consecutive
patients who underwent surgery for thoracolumbar metastatic spine disease (MSD) from January 2011 to October
2017. Patients were divided into minimally invasive spine
surgery (MISS) and open spine surgery (OSS) groups.
Patients with spinal instability were treated with PPSF
or OPS with pedicle screws. Patients with MSCC weretreated with MOSS or OPSD. Outcomes measured included intraoperative blood loss, operative time, durationof hospital stay, and improvement in ASIA score. Time toinitiate radiotherapy and perioperative surgical or nonsurgical complications were also recorded.

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Asian Spine J 2021;15(Supplement 1):S1-S177

Results: There were 200 eligible patients, of which 61
underwent MISS and 139 OSS for MSD. There was no
significant difference in baseline characteristics between
patients undergoing MISS and OSS. In the MISS group,
28 patients (45.9%) were treated for spinal instability and33 patients (54.1%) were treated for MSCC. Whilst in the
OSS group, 15 patients (10.8%) were treated for spinal
instability alone and 124 (89.2%) were treated for MSCC.
Patients who underwent PPSF were found to have significantly lower blood loss (95 mL vs. 564 mL, p<0.001) andsurgical complication rates (p<0.05) with shorter length ofstay (6 days vs. 19 days, p<0.001) when compared to the
OPS group. Patients who underwent MOSS had significantly lower blood loss (602 mL vs. 1,008 mL) and shorter
length of stay (10 days vs. 18 days, p=0.008) versus the
OPSD group.
Conclusions: This study demonstrates the benefits of PPSF
and MOSS over OPS and OPSD for the treatment of MSD
with spinal instability and MSCC, respectively.

PS-FP-6-18

Do aggressive Vertebral Hemangiomas Warrant
Aggressive Surgery?: Inferences from a
Retrospective Surgical Cohort of 23 Patients
Guna K. Pratheep, Sri Vijay Anand,Rajasekaran Shanmuganathan, Ajoy Prasad Shetty,
Rishi Mugesh Kanna
Division of Spine Surgery, Department of Orthopaedics, Ganga Medical
Centre and Hospital, Coimbatore, India

Purpose: Aggressive vertebral hemangiomas (AVH) area rare subset of benign vascular tumors that frequently
presents with compressive myelopathy. Surgery for AVH
can be challenging, owing to the high vascularity of thetumor. Though the results of surgical management have
improved over time, there is a lack of consensus on theideal management of this group of patients. With thisbackground, we evaluated the outcomes of our surgicalcohort.
Methods: We did a retrospective analysis of 23 patients
operated on for aggressive vertebral hemangioma between 2009 to 2019 in our institute. Minimum followup period was 2 years. The demographic, clinical details
were retrieved from the hospital information system andtelephonic interviews. Imaging (radiographs, computed
tomography scan, and magnetic resonance imaging) of
all patients were accessed and analyzed in the picture archiving and communication system. Tumor staging wasdone by Enneking staging, Weinstein-Boriani-Biagini(WBB), and spinal instability neoplastic score. The neurological recovery and recurrence rate were noted at followup.
Results: Fifteen females, including three in the peripartum
period and eight males with a mean age of 46.39±17.47
years, formed the study group. Gait instability (39.13%),pain (30.43%) radiculopathy (17.39%), and weakness(13.04%) were the presenting symptoms. Thirteen patients
had neurodeficit (American Spinal Injury Association[ASIA] A-1, ASIA C-2, ASIA D-10). The most commonsite of lesion was the thoracic spine (n=13), followed bythoracolumbar (D11–L2, n=8) and lumbar region (n=2).
The lesion was solitary in 56.52% (n=13) and multiple in
43.48% (n=10). A rare occurrence of two-level symptomatic AVH was noted in one patient. Surgical intervention
was heterogeneous (intralesional spondylectomy withreconstruction, n=10; vertebroplasty, stabilization, anddecompression, n=6; decompression and stabilization,n=6; decompressive laminectomy, n=1). Preoperative
embolization reduced intraoperative blood loss and enabled tumor removal. A difference in mean blood loss between non-embolization and pre-embolization was noted(1,416.6 mL vs. 812.2 mL). All the patients had improvement of neurology and only two recurrences were noted
in a mean follow-up of 55.78±25.03 months.
Conclusions: Aggressive vertebral hemangiomas are benign tumors, and intralesional spondylectomy offers agood outcome with less recurrence rate. WBB staging is
helpful in decision making. Preoperative embolization issafe, helps reduce intraoperative blood loss, and enables
tumor removal. Pregnancy increases the chance for symptomatic AVH, and treatment in antepartum needs to be
individualized.

Asian Spine Journal
PS-FP-7-2

Micro-organisms and Outcome of Spinal
Infections: A Report of 48 Cases
Quang Minh Luong, Duong Van Pham,
Hung Dinh Nguyen

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Conclusions: SI is commonly caused by S. aureus, a highrisk in diabetic patients who undergo spinal injection orsurgery with blood transfusion. The complication of SI ismore severe and treatment outcome is worse in postoperative and post-injection SI groups.

Saint Paul General Hospital, Hanoi, Vietnam

PS-FP-7-6

Purpose: Spinal infection (SI) is a common serious disease that can cause severe damage and disability. Recent
literature trends suggest an increasing prevalence of SI.
To avoid SI’s sequelae, determining an early diagnosis andtreatment is essential. This study aimed to describe microorganisms and outcome of the treatment for some of SI’s
types.
Methods: A total of 48 patients with SI admitted at thespine unit of our hospital from 2015 to 2019 were classified into three groups based on its causes: spontaneous(n=19), post-spinal injection (n=17), and postoperation(n=12). Microorganisms, locations, complications, treatment approaches, and the outcome were analyzed.
Results: General information: male/female ratio (1.875);
mean age (49 years). Pathogens: Staphylococcus aureus(52.1%); tuberculosis (29.2%); Escherichia coli (4.2%);
Candida albicans (4.2%); 2 pathogens (2.1%); unknown(8.2%). Location: cervical (10.4%); thoracic (16.7%); lumbar (60.4%); sacroiliac joint (4.2%); para-spinal muscular(2.1%); spinal epidural abscess (6.2%). Group 1: spontaneous SI (n=19): pathogens: tuberculosis (73.7%); S. aureus(26.3%). Complications: sepsis (3/19, 15.8%). Treatment:
conservative, 21%; surgery, 79%. Outcome: good (84.2%);
fair (5.3%); bad (10.5%). Group 2: post-spinal-injection
SI (n=17): risk factors: diabetes mellitus (41.7%). Typeof spinal injection: acupuncture (11.8%); vertebroplasty(17.6%); trigger point and epidural injection (70.4%).
Pathogens: E. coli (5.9%), C. albicans (11.8%), S. aureus(82.3%). Complication: sepsis (41.7%). Treatment: surgery(52.9%); conservative (47.1%). Outcome: good (52.8%),
fair (23.6%); bad (23.6%). Group 3: postoperative SI(n=12): risk factors: diabetes mellitus (25%); blood transfusion (50%). Pathogens: S. aureus (50%); E. coli (8.3%);
multiple pathogens (8.3%); unknown (33.3%). Complications: sepsis (33.3%); multiple organ failure (16.6%);
mortality (1/12, 8.4%). Treatment: conservative (58.3%);
surgery (41.7%). Outcome: good (33.3%); fair (33.3%);
bad (33.4%).

A Validated Score for Evaluating Spinal Instability
to Assess Surgical Candidacy in Active Spinal
Tuberculosis: An Evidence-Based Approachand Multinational Expert Consensus Study
Dilip Chand Raja Soundararajan, S. Rajasekaran,
Ajoy Prasad Shetty, Rishi Mugesh Kanna
Department of Spine Surgery, Ganga Hospital, Coimbatore, India

Study Design: Modified Delphi consensus and observational study.
Purpose: To develop an objective scoring system to determine instability in spinal tuberculosis (STB).
Overview of Literature: Multidrug chemotherapy has
made STB mainly a medical disease. However, instability
in STB leads to disabling spinal deformity and neurological deficit. The ability to identify and estimate instability
remains largely subjective based on experience resulting
in overdo or delayed surgical treatment with serious consequences to the patient.
Methods: The study was conducted in four phases: (1) A
10-member expert panel of spine surgeons with 25 years’
experience performed an extensive review of literature
to enlist all factors influencing management in STB anda questionnaire was developed; (2) 68 experienced spine
surgeons from 12 different nations opined on the importance of each factor in an online survey; 5 factors deemed
important by >70% of participants were included forfurther analysis; (3) 60 representative cases of STB wereanalyzed for several factors and their association with instability; a preliminary scoring system was developed andthreshold score for determining instability was derived;and (4) results were validated in a new set of 30 cases; 10
spine fellows and orthopedic residents naïve to the scoring
system evaluated these cases before and after employing
the scoring system and the overall agreement, reliability
and reproducibility were analyzed. This project was selffunded.

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Results: A total of 68 of 76 of the invited spine surgeonsparticipated and factors considered important by >70% of
the participants were ‘spine at risk’ signs deemed important by all (100%), followed by severity of vertebral bodyloss (89.56%), cervico-thoracic/thoraco-lumbar junction involvement (86.57%), age below 15 at presentation(85.07%), and kyphotic deformity ≥30° (80.60%). All these
five factors considered in the scoring system were foundto be associated with instability: age ≤15 years (p=0.05),
cervicothoracic/thoracolumbar junction involvement(p=0.028), sagittal deformity angle ratio ≥15° (p<0.001),
vertebral body loss-segmental ratio ≥0.5 (p<0.001), andpresence of spine at risk signs (p<0.001). A total score of≥3/10 was indicative of definite instability with a goodsensitivity (77%) and excellent specificity (100%). The
scoring system was validated in a new set of 30 cases withexcellent accuracy.
Conclusions: A simple objective method of scoring systemfor predicting instability in STB has been developed using five main factors: young age, junctional involvement,
severity of deformity, vertebral body loss, and presence ofspine at risk signs.

PS-FP-7-7

Clinical, Radiological and Microbial Profile ofPyogenic Spondylodiscitis: Single-Center Data
Analysis of 48 Patients
Dheeraj Manikanta Maddali, Saumyajit Basu
Kothari Medical Center, Kolkata, India

Purpose: Pyogenic spondylodiscitis is defined as an infection of the intervertebral disc and/or adjacent vertebrae.
It may occur due to hematogenous seeding during bacteremia, direct spread from an adjacent focus of infection,or inoculation during spinal surgery. The incidence ofspondylodiscitis appears to be increasing due to the aging
population with multiple comorbidities. However, there isa critical lack of information about natural history, longterm clinical outcomes, patient- and disease-related factors that contribute to clinical outcomes. Our objective isto describe the clinical, radiological, and microbial profiles in 48 patients.
Methods: A retrospective single-center study of 48 patients from the electronic medical record. Data were ob-tained regarding clinical and radiological features and themicrobiological diagnosis was recorded.
Results: The mean age was 52 years (range, 7–93 years),
73% of these patients are males. A pre-existing condition
causing impaired immunity was present in 27 patients(56.2%): eight had diabetes mellitus, 10 had urinary tract
infections, five had chronic kidney disease, one had rectal
carcinoma, three had cholangitis, and three had epididymo-orchitis. Five patients (10.4%) had history of spinal
surgery. Pain was the most common symptom, fever wasabsent in 17 patients (35.4%), and neurological deficit wasseen in 10 patients (20.8%). Mean duration of symptoms
was 3 weeks. Most common site is lumbar spine (n=21)
followed by lumbosacral junction (n=15) and thoracic
spine (n=10), and cervical spine (n=2) is the least common site. Two-disc space involvement is seen in two patients. Most common source of infection is hematogenous(22 patients [45.8%]), and an intra-abdominal pathology
is seen in four patients (8.3%). Bacteria isolated from cultures in 35 patients and Gram positive seen in 20 patients(41.2%) and Gram negative seen in 15 patients (31.25%).
Multiple organisms are identified in five patients (10.4%).
Most common organism is Staphylococcus aureus followed by Escherichia coli.
Conclusions: We conclude that immunocompromised
patients and those with medical comorbidities have a highrisk of developing spondylodiscitis.

PS-FP-7-8

Treatment Results of Percutaneous Posterior
Lumbar Pelvic Fusion for Lower Lumbar
Purulent/Tuberculous Discitis
Yuji Kasukawa, Naohisa Miyakoshi, Michio Hongo,
Yoshinori Ishikawa, Daisuke Kudo, Yoichi Shimada
Department of Orthopedic Surgery, Akita University Graduate School of
Medicine, Akita, Japan

Purpose: Antibiotics are the basic treatment for purulent
or tuberculous discitis, but for cases with abscess formation and/or bone destruction of the endplate of vertebra,
percutaneous disc dissection and drainage for the affecteddisc, and further percutaneous posterior fusion is performed on the cranio-caudal side of the infected disc sothat activity can be restored at an early stage. However,Asian Spine Journal
posterior fusion for discitis in the lower lumbar spine issomewhat difficult. In this study, we investigated the results of percutaneous posterior lumbar pelvic fusion forpurulent or tuberculous discitis of the lower lumbar spinewith vertebral body destruction.
Methods: Nine patients, who underwent percutaneous
posterior fusion from the lower lumbar spine to the pelvis
for discitis that occurred in L4–5 and/or L5–S1 with destruction of the endplate of the vertebral body from 2016
to 2019 (eight males and one female, with an average ageof 71 years), were included in this study. We investigatedcomorbidities, preoperative treatment period, level ofdiscitis, causative bacteria, surgical procedure, Japanese
Orthopaedic Association (JOA) score as well as JOA subscore of activities of daily living/walking ability at preoperative and final observation (15 months on average), andpostoperative course.
Results: All patients had comorbidities including four cases with diabetes and atrial fibrillation in two cases each,
one case of infectious aortic aneurysm, one case of caries,
and three cases of the others. The average preoperative
treatment period is 1 month, and the level of discitis was
L3–4 and L4–5 in one case, L4–5 in three cases, L5–S in
two cases, and L4–5 and L5–S in three cases. The causative bacteria were Staphylococcus mutans, Methicillinresistant coagulase-negative staphylococcus, Enterococcus
faecium, tubercle bacillus, and so forth in one case each,
and unknown in three cases. The mean JOA score improved significantly to 2.6 preoperatively and 10.8 at the
final observation (p<0.01). Mean JOA sub-scores of activities of daily living and walking ability were significantly
improved from 2.6 and 0.1 before surgery to 10.8 and 1.9
at the final observation (p<0.001). One case each died ofbleeding from an infectious abdominal aortic aneurysm,
and one case where discitis spread to the upper lumbar
spine and extended fixation to the lower thoracic spine.
Conclusions: Percutaneous posterior lumbar pelvic fusion for lower lumbar discitis significantly improved JOA
scores as well as JOA sub-score of activities of daily living
and walking ability.

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PS-FP-7-9

Trends in Infectious Spondylitis from 2000 to
2020
Shinji Tanishima, Tokumitsu Mihara, Chikako Taked,
Masaki Yoshida, Hideki Nagashima
Division of Orthopedic Surgery, Department of Sensory of Motor Organs,
School of Medicine, Tottori University Faculty of Medicine, Yonago, Japan

Purpose: Infectious spondylitis was a relatively raredisease in the past; however, it is becoming more common now. The reason for this trend is predicted to be thechange in the disease and patient characteristics. This
study aimed to investigate the trends in infectious spondylitis in the past 2 decades.
Methods: Our study included 157 cases, from 2000 to
2020, of infectious spondylitis such as purulent spondylitis and tuberculous spondylitis. Cases were divided into
two groups: group 1 (2000–2009; 82 cases: 57 males and
25 females) and group 2 (2010–2020; 75 cases: 46 males
and 29 females). Age, gender, causative organism, and localization examined and compared between the groups.
Results: The highest morbidity was in lumbar spine infections in both groups. The proportion of women was 30.5%
in the group 1 and 38.7% in the group 2, with no significant difference (p=0.28). The average age was significantly
higher in the group 2 (72.6 years) than in the group 1 (68.8
years, p<0.01). Compromised hosts were the cause of
infection in 52.4% of the group 1 and 36.0% of the group2, showing a significant difference. Bacterial identification rate was 70.1% in the group 1 and 77.3% in the group2 (p<0.01), and the genus Staphylococcus was the mostcommon bacteria. The proportion of resistant bacteriasuch as Methicillin-resistant Staphylococcus aureus was
27.3% in the group 1 but only 6.7% in the group 2 (p<0.01).
Conversely, infectious diseases caused by indigenous bacteria in the oral cavity and intestines were more common
in the group 2 (37.8%) than in the group 1 (13.0%), showing a significant difference (p<0.01).
Conclusion: Since 2000, infectious spondylitis trends havechanged when evaluated every 10 years. In recent years,
infections caused by indigenous bacteria have increased
more than those caused by resistant bacteria, and thecausative bacteria are believed to have changed due to theincreased age of patients over the 2 decades.

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PS-FP-7-10

Status and Trends of Causative Bacteria of
Surgical Site Infection in Spinal Surgery: A
Study on 6,411 Cases
Takahito Iga, Satoshi Suzuki, Satoshi Nori, Osahiko Tsuji,
Narihito Nagoshi, Eijiro Okada, Mitsuru Yagi,
Masaya Nakamura, Morio Matsumoto, Kota Watanabe
Department of Orthopedic Surgery, Keio University School of Medicine,Tokyo, Japan

Purpose: Surgical site infection (SSI) after spinal surgery isa significant problem for patients and healthcare economics—various preventive measures, including prophylactic
drug administration. We investigated the trend of SSI
rates and the trend of causative bacteria in our department over the past 10 year.
Methods: We investigated the details of postoperative SSI
in all spinal surgery cases (6,411 cases) performed at our
hospital from 2010 to 2019. Postoperative SSI was definedas cases requiring debridement and curettage in the operating room. In our department, cefazolin is usually used
as a prophylactic antibacterial drug, and teicoplanin isalso administered to patients at high risk of infection (caseswith diabetes, reoperation, etc.). The cases were divided
based on the presence or absence of spinal implants, andthe first half (2010–2014) and the second half (2015–2019)of the studied period. Recent trends in SSI rate were investigated retrospectively using these groups.
Results: The overall SSI rate in the first half was 1.43%,
then decreased significantly to 0.88% in the second half.
In cases without implants, the first half 's SSI rate was
1.07%, then decreased significantly to 0.37% in the second
half. In cases with spinal implants, there was no significant difference in SSI rate between the first and second
half (1.99% vs. 1.58%). In cases without implants, SSIs
were mainly caused by multidrug-resistant bacteria in thefirst half (seven cases/18 cases). In the second half, theproportion was decreased (seven cases/25 cases). In casewith spinal implants, the causative bacteria of multidrugresistant bacteria decreased (nine cases/22 cases → sevencases/25 cases). However, the number of cases with Propionibacterium acnes increased in the second half (twocases/22 cases → 11 cases/25 cases). In all cases with P.
acnes, all patients underwent posterior spinal fixation foradolescent idiopathic scoliosis and suffered late-onset SSI(five cases/five cases).
Conclusions: We investigated the trends of SSI rates andthe causative bacteria of SSI in spinal surgery at our hospital. In recent years, cases of SSI due to P. Acnes increasedin AIS cases, and a modification of the perioperative protocol is required.

PS-FP-7-11

Gene Xpert/MTB RIF Assay for Spinal
Tuberculosis
Siddharth Aiyer, Vijay Karthek, Pramod Bhilare,
Shailesh Hadgaonkar, Ajay Kothari, Ashok Shyam,
Parag Sancheti
Sancheti Institute for Orthopaedics and Rehabilitation, Pune, India

Purpose: Xpert MTB/RIF assay is a rapid automated molecular test with excellent reported sensitivity, specificity
for diagnosis of pulmonary and extrapulmonary Mycobacterium tuberculosis (MTB) infections. However, theclinical utility and accuracy in STB is not well established.
The objective of the study was to report on the sensitivity,
specificity and clinical utility of the Xpert MTB/RIF assay
in spinal tuberculosis (STB).
Methods: A retrospective review of medical records were
performed for 136 patients that underwent spinal biopsy
for suspected spondylodiscitis. Reports for acid fast bacilli(AFB) smear, gram stain, pyogenic culture, MTB culture,
histopathology, Xpert MTB/RIF assay, and drug sensitivity testing were reviewed. “Reference standard for diagnosis of STB” was based on positive histopathology and/or
MTB culture evidence and were considered as MTB positive. Any samples returning a positive pyogenic or fungal
culture were considered as MTB negative. The sensitivity,
specificity for Xpert MTB/RIF was assessed against thereference standard.
Results: A total of 125 patients were considered for final analysis, 86 patients met the criteria for “reference
standard for diagnosis of TB spine” (MTB positive). This
includes nine patients that were MGIT culture only positive; 45 that were histopathology only positive and 32
were both culture and histopathology positive. There were
39 culture-proven (pyogenic, 37 and fungal, 2) patients
included in MTB negative group. Of the 86 MTB samples
that were positive 53 (61.6%) were tissue and 33 (38.4%)

Asian Spine Journal
were pus samples respectively. In our series, the overall
analysis showed a 65.1% sensitivity, 100% specificity, 100%
positive predictive value, and 56.5% negative predictive
value for the Xpert MTB/RIF.
Conclusions: Gene Xpert MTB/RIF showed excellent
specificity and was accurate in the identification of drug
resistance. The sensitivity was 65% which was lower thanreported previously in other series for spinal tuberculosis.
Sampling techniques using pus samples rather than tissue
samples could be a possible reason for lower sensitivity.

PS-FP-7-12

Does Forced-Air Warming Increase SurgicalSite Infections in Spine Surgery? A Propensity
Score-Matched Analysis
Kyoichi Handa1, Haruo Kanno2, Shigetsune Matsuya3,
Kohei Takahashi1, Ko Hashimoto1, Toshimi Aizawa1
1

Department of Orthopaedic Surgery, Tohoku University School of Medicine,
Sendai, Japan2
Department of Orthopaedic Surgery, Tohoku Medical and Pharmaceutical
University School of Medicine, Sendai, Japan3
Department of Orthopaedic Surgery, Tohoku Rosai Hospital, Sendai, Japan

Purpose: Forced-air warming (FAW) systems have been
widely used to prevent hypothermia under anesthesia
during various surgeries. Several previous reports havesuggested that FAW increases the incidence of surgicalsite infection (SSI) after joint replacement. However, there
has been no study to investigate whether FAW increase
SSI following spine surgery. The purpose of this study is tocompare the incidence of SSI between with and without
FAW in spine surgery.
Methods: This study analyzed 245 patients who underwent spine surgery. Clinical characteristics such as age,gender, body mass index, the American Society of Anesthesiologists physical status (ASA-PS), diagnosis of diabetes mellitus, and current smoking habits were investigated. Surgical data such as surgical site, previous surgery
at same site, operative time, intraoperative blood loss, anduse of spinal instrumentation were evaluated. The patientswere divided into two groups according to whether FAW
was used or not during surgery. The application of FAW
was determined by anesthesiologists. Among all participants in this study, the clinical characteristics, surgical
data and incidence of SSI were compared between the two

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groups. To estimate the incidence of SSI without potential
biases due to various confounding factors, a propensity
score pairwise matching was performed between the twogroups.
Results: The FAW was used in 45 patients, and 200 patients underwent surgery without FAW. The incidenceof SSI tended to be higher in patients with FAW (8.9%)
compared to those without FAW (3.0%) (p=0.07). Patientswith FAW were significantly higher ASA-PS, longer operative time, larger intraoperative blood loss, and more
use of instrumentation compared to those without FAW(p<0.01). Propensity matching yielded 39 pairs of patientswith and without FAW. In the propensity score-matchedanalysis, the number of patients who developed SSI was
no significant difference between patients with (10.3%)
and without FAW (7.7%) (p=0.69).
Conclusions: There have been many studies to investigate
whether the use of FAW during joint surgery increases
risk of SSI or not, but it remains controversial. The present study compared the incidence of SSI between withor without FAW in spine surgery for the first time. In thepresent study using a propensity score-matched analysis,
FAW did not significantly increase the incidence of SSI.
Therefore, FAW can be used for the maintenance of intraoperative normothermia during spine surgery without
increasing risk of SSI when it used properly.

PS-FP-7-13“Spine Surgery Checklist” a Step Towards
Perfection Through Protocols
Jwalant Y. Patel, Arvind G. Kulkarni
Bombay Hospital and Medical Research Centre, Mumbai, India

Study Design: Prospective observational study.
Purpose: To evaluate the effectiveness of a novel checklist
designed specifically for “spine-surgery-subspecialty”, as ameans to reduce some of the common preventable humanerrors and major perioperative complications in spine
surgery.
Overview of Literature: We propose a unique set of spine
surgery specific checklist that recognizes the risk factors,
anticipates the possible human errors, and thus can help
to prevent their occurrence. This checklist is associatedwith increased patient safety awareness, improved com-

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munication (keeps everyone updated regarding their responsibilities), reduction of surgical claims, and reductionin the number of postoperative complications including
mortality.
Methods: It was a prospective pilot study performed ata single center including a total of 858 spine surgicalpatients. The patients were divided into two groups: thestudy group (after implementation of the checklist [2016–2017]) and the control group (before the implementationof the checklist [2015–2016]). The incidence of common
preventable human errors and major perioperative complications in spine surgeries were recorded and compared
between the two groups.
Results: The incidence of wrong-level surgeries was 0%.
The overall incidence of preventable errors was 1.22%(5/410). The rate of adverse, near-miss, and no-harm
events was 0%, 0.73% (3/410), and 0.48% (2/410), respectively. The preoperative, intraoperative, and postoperative errors were 0.48% (2/410), 0.24% (1/410), and
0.48% (2/410), respectively. The reoperation rate related
to preventable errors reduced after checklist implementation. There were significant differences noted in the total
preventable errors related to complications like infections,prolonged hospital stays, and unplanned hospital readmission/revision surgeries (p<0.001).
Conclusions: The authors proposed first of its kind spine
surgery-specific checklist which is comprehensive involving perioperative parameters. The checklist is easy, safe,and effective to reduce unforgiving errors and perioperative complications. However, its broader implementation
would require its validation through large multicenter andrandomized control studies.

PS-FP-7-14

outcomes of patients who suffered concomitant spinal
and non-spinal osteoarticular infections. Treatment ofpyogenic spondylodiscitis or arthritis can be complicatedwith a variety of concomitant infectious processes. To thebest of our knowledge, no study has to date focused onconcomitant osteoarticular infections.
Methods: Between May of 2015 and May of 2019, patientsover 18 years old, who were diagnosed and treated for spinal infections (spondylodiscitis and facet joint infection)or non-spinal infections (septic arthritis), were included.
There were six patients with concomitant spinal and nonspinal ostoarticular infections (CI group), 31 patientswith spinal infection alone (SA group), and 18 patientswith arthritis alone (AA group). The data gained from thepatients in the CI group were compared those in the SAgroup and the AA group.
Results: Factors contributing to statistical significanceincluded past or present history of cancer (100% in the CI
group, 29% in the SA group and 33% in the AA group),
CRP levels (27.4 mg/dl in the CI group, 13.4 mg/dl in the
SA group, and 13.8 mg/dl in the AA Group), albumin levels (2.4 g/dl in the CI group and 2.9 in both the SA groupand the AA group), detection of Group B Streptococcus(GBS) (50% in the CI group, 3.2% in the SA group and5.6% in the AA group), and duration of intravenous antibiotic therapy (131 days in the CI group, 66 days in the SAgroup and 29 days in the AA group).
Conclusions: Patients with concomitant spinal and nonspinal osteoarticular infections were more likely to present
with a past and present history of cancer, hypoalbuminemia, higher levels of CRP and GBS bacteremia. Furthermore, they required prolonged courses of intravenous
antibiotic therapy.

PS-FP-7-15

Analysis of Clinical Features Regarding
Concomitant Spinal and Non-spinal
Osteoarticular Infections

Consecutive Occurrence of Septic Arthritis
and Pyogenic Spondylitis in Two Patients

Ryunosuke Fukushi1, Satoshi Kawaguchi2,
Toshihiko Yamashita1

Ryunosuke Fukushi1, Satoshi Kawaguchi2,
Toshihiko Yamashita1

1Department of Orthopaedic Surgery, Sapporo Medical University School of
Medicine, Sapporo, Japan2
Department of Orthopedic Surgery, Asahikawa Kosei Hospital, Asahikawa,Japan

Objective: To reveal clinical characteristics and treatment

1

Department of Orthopaedic Surgery, Sapporo Medical University School of
Medicine, Sapporo, Japan2
Department of Orthopedic Surgery, Asahikawa Kosei Hospital, Asahikawa,Japan

Pyogenic spondylodiscitis and arthritis are serious infec-

Asian Spine Journal
tious diseases. A combination of these two conditions
makes treatment more difficult. The patient in case 1 is an
86-year-old female with a past medical history of breast
and thyroid cancers. She was brought to our emergency
room suffering from severe low back pain. Magnetic
resonance imaging (MRI) showed discovertebral signal
changes in the L2–L4 vertebrae. Blood cultures confirmed
Streptococcus agalactiae. Intravenous antibiotic therapy
was initiated. On day 24, the patient began to complain of
pain in her left shoulder. MRI revealed synovial effusion.
Arthroscopic debridement was then performed. Pathological analysis revealed an infiltration of neutrophils in the
synovial tissue specimens. In contrast, her back pain continued to be severe despite treatment using a hard brace.
MRI taken on day 50 showed a progressive destruction of
the vertebral bodies. The patient underwent percutaneous
posterior instrumentation. On day 70, the septic arthritis
in the left shoulder recurred and arthroscopic irrigation
was carried out again. Corynebacterium striatum was
detected in the synovial fluid cultures. We changed theantibiotics to vancomycin, which was judged sensitive toboth Streptococcus and Corynebacterium. The C-reactive
protein levels were normalized on day 122. The patient incase 2 is an 87-year-old male with a past medical historyof stomach cancer, diabetes mellitus, and bullous pemphigoid. He was referred to our clinic with a 1-week historyof right shoulder pain and high fever was noted the day
before arrival. MRI of the right shoulder showed synovial
effusion. Gram staining of the shoulder aspirates indicated Gram positive bacteria. Arthroscopic debridement of
the right shoulder was performed. Staphylococcus aureus
was detected in the blood and the synovial fluid cultures.
Intravenous antibiotic therapy was initiated. The patient
started to complain of low back pain on day 27. MRI revealed a fluid accumulation in the L1/2 intervertebral discwith signal changes at the adjusting endplates and the vertebral bodies, which is consistent with pyogenic spondylodiscitis. A hard corset was placed on the patient. Surgicaltreatment was declined by the patient and his family. On
day 121, the patient suffered a cardiopulmonary arrest.
This was due to a pulmonary embolism. A concomitanceof pyogenic spondylodiscitis with septic arthritis is possible in immunocompromised senile patients. Causative
microorganisms can be different between spondylodiscitis
and arthritis. Thereby diagnostic intervention to each locus is recommended. The correct timing to proceed withsurgery is critical.

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PS-FP-7-16

A Case of Glossopharyngeal and Hypoglossal
Nerve Paralysis Secondary to Pyogenic Cervical
Facet Joint Arthritis
Ryunosuke Fukushi, Izaya Ogon, Toshihiko Yamashita
Department of Orthopaedic Surgery, Sapporo Medical University School of
Medicine, Sapporo, Japan

Jugular foramen syndrome is a rare systematic cranial
neuropathy showing characteristic clinical symptoms due
to jugular foramen cranial nerve paralysis. Carotid spacelesions can cause cranial neuropathy. Both jugular foramen syndrome and carotid space lesions have been reported rarely in patients in otolaryngology. No cases havebeen reported in orthopedics. We report a case of cranial
neuropathy caused by cervical pyogenic intervertebral
arthritis. A 50-year-old man presented with severe neckpain, fever, and difficulty breathing. He was admitted tothe orthopedics department with possible retropharyngeal abscess and pyogenic spondylitis. Antibiotic therapy
was initiated; however, due to poor oxygenation, he wasreferred and admitted to our department. Magnetic resonance imaging showed signal changes at the left C1/2
lateral atlantoaxial joint, posterior pharynx, longus colli,
carotid space, and medial deep cervical region, predominantly on the left side. Despite lymph node enlargementfrom the posterior pharynx to deep cervical region, there
was no abscess formation. There were no signs of spaceoccupying lesion or signal changes in the jugular foramen. One day post-admission, his temperature had risen
to 39.1ºC, SpO2 had fallen, and neck pain had worsened.
Emergency surgery was decided. We suspected retropharyngeal abscess and pyogenic spondylitis. Intraoperatively,
no abscess formation in the posterior pharynx, vertebral
bodies, or anterior to the intervertebral discs was seen.
Irrigation was performed with physiological saline, and adrain placed. Postoperatively, white blood cell count andC-reactive protein levels had decreased. On day 13 postadmission, the patient had dysphagia, deviated tongue
protrusion, and curtain sign. Glossopharyngeal and hypoglossal nerve paralysis was diagnosed. The patient’s swallowing functions recovered, and he was discharged on
day 36. The patient had hypoglossal nerve paralysis, andwe suspected that this was from pressure on the carotid
space. Lateral retropharyngeal lymph nodes (LRPLN) areS122

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present on the medial carotid space, which contains theglossopharyngeal and hypoglossal nerves. The infection
can lead to LRPLN enlargement, resulting in pressure on
the carotid space from medial to lateral, and cause glossopharyngeal and hypoglossal nerve paralysis.

PS-FP-7-17

Clinical Significance of Comprehensive
Medicine for the Treatment of Pyogenic
Spondylitis in the Elderly
Hidekazu Yoshizaki, Tzong-Jing Victor Wang, Manabu Ito
Department of Orthopaedic Surgery, National Hospital Organization
Hokkaido Medical Center, Sapporo, Japan

Purpose: In recent years, the number of refractory spinal
infections in elderly patients with diverse comorbidities
has been increasing in Japan. In addition, elderly people
are prone to low nutritional status due to age-related eating disorders and changes in digestion and absorptionfunctions. In this study, we examined the clinical efficacy
of combining conventional orthopedic single-discipline
treatment with multi-disciplinary comprehensive medical
treatment of pyogenic spondylitis in the elderly.
Methods: The study included 54 patients aged 65 years
and older who were treated for pyogenic spondylitis
between 2016 and 2019. The patients were divided into
two groups: 41 patients managed by a single orthopedic
department (non-intervention group) and 13 patientsmanaged with a combination of conventional orthopedic
single-specialty treatment and comprehensive medical
treatment care. In addition to conventional single discipline care, the Japanese Nurse Practitioner (JNP) played acentral role in comprehensive medical care by treatment
strategy. The JNP also played an active role in the correction of polypharmacy such as reduction of these medications may be risky for the elderly when used excessively.
Serum albumin level was used for nutritional assessment
and Barthel Index for quality of life assessment, and thedegree of improvement between the two points was calculated at admission and discharge.
Results: The per capita doses of nonsteroidal anti-inflammatory drugs and opioid analgesics were reduced to
13% and 9% of the non-intervention group, respectively,
resulting in acetaminophen-centered analgesic control.

The mean serum albumin level at admission was 2.94 g/
dL in the non-intervention group and 2.62 g/dL in theintervention group. At discharge, it was 3.16 g/dL in the
non-intervention group and 3.32 g/dL in the intervention group. The mean Barthel Index at admission was
23.1 points in the non-intervention group and 18.2 points
in the intervention group. There was an improvementof Barthel Index to 38.8 points in the non-intervention
group compared to 44.1 points in the intervention groupby discharge. There was a significant improvement in theintervention group compared to the non-intervention
group (p<0.05).
Conclusions: Nutritional and pharmaceutical management of elderly infected patients is an important factor in
determining the outcome of surgical care. Although JNP
in Japan is still not well recognized, we believe that it is an
important and effective profession for the developmentof comprehensive medical care, and we hope to improve
clinical outcomes by implementing it in conjunction withorthopedic care.

PS-FP-7-19

Tuberculous Osteomyelitis of the Ischium: A
Case Report and Review of Literature
Chandhan Murugan, Ajoy Shetty,
Rajasekaran Shanmuganathan
Department of Spine Surgery, Ganga Medical Centre and Hospitals Pvt.
Ltd., Coimbatore, India

Gluteal pain can be a presenting symptom of numerous
pathologies arising from the spine, pelvis and hips andcan pose a challenging problem to orthopedic surgeons.
We report a unique case of tuberculous osteomyelitis of
the ischium in a young immunocompetent individual
presenting as gluteal pain. A high index of suspicion, early
diagnosis and prompt management is mandatory to promote complete healing and prevent complications.

Asian Spine Journal
PS-FP-7-21

Characterization of Biofilms in Explanted
Pedicle Screws Retrieved from Aseptic
Pseudarthrosis Cases
Daksh Jayaswal1, Aakash Agarwal2, Megan Mooney1,
Ashish Agarwal3, Arvind Jayaswal3, Amey Kelkar1,
Gayane Saakyan1, Vijay Goel1, Vithal Shendge1,
Hossein Elgafy1
1

Departments of Bioengineering and Orthopedic Surgery, Colleges ofEngineering and Medicine, University of Toledo, Toledo, OH, USA
2
Spinal Balance Inc., Swanton, OH, USA
3
Primus Super Specialty Hospital, New Delhi, India

Purpose: A previous retrieval analysis of implants frompatients with pseudoarthrosis and pedicle screw loosening
show high levels of bacterial contamination at the pedicleof the vertebra. Recent literature has highlighted the correlation of pseudarthrosis and pedicle screw loosening
with subchronic infection at the pedicle of the vertebra.
The objective of the current study is to characterize thesupposedly “aseptic” pedicle screw loosening in patients
undergoing revision surgery and to determine both thefrequency and visual architecture of biofilms on implantsurfaces.
Methods: Pedicle screw explants from 10 consecutive
patients undergoing revision spine surgery for pseudarthrosis were collected and fixed in 3% glutaraldehyde
solution. The exclusion criteria were as follows: age <18years; surgery for causes related to trauma, tumors, or primary infection; use of cemented screws; an anterior- only
approach; and lack of radiographic data (to determine
the presence or absence of radiolucent rim and confirm
screw loosening). From the collected samples, eight patient swabs from tissues around the implants were sent for
cultures to assess bacterial infiltration in tissues beyond
the biofilm. Additionally, each of these implants were analyzed thoroughly by using scanning electron microscopy
and X-ray spectroscopy to evaluate the architecture of thebiofilm. The implants were also analyzed using energy
dispersive X-ray spectroscopy. Pearson’s correlation coefficient statistics was used to measure the linear correlation
between the two paired variables, namely, screw loosening
and biofilm.
Results: The study was successful in capturing the visualarchitecture of the biofilm on retrieved implants. A total of 77% of pseudarthrosis cases presented with loose

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pedicle screws, and 72% of cases showed biofilms on theimplants. Statistical tests demonstrated that the confirmed
cases of screw loosening (as identified by radiographichalo) and the detection of biofilms were positively correlated. Areas with biofilms always tested negative for
calcium phosphate (bone mineralization), whereas areas
without biofilms tested positive for calcium phosphate.
Intraoperative tissue and swab cultures of the surrounding
screws did not demonstrate bacteria growth on cultures.
Conclusions: In the absence of the clinical presentationof infection, impregnated bacteria could form a biofilm
around an implant, and this biofilm can remain undetected via contemporary diagnostic methods, including
swabbing. Implant biofilm is frequently present in “aseptic”
pseudarthrosis cases. The major limitation of this study is
its relatively small sample size and the statistical nonsignificant correlation between screw loosening and biofilms.

PS-FP-7-22

How Does the Absence or Presence of Pedicle
Screw Guard Effect Bacterial Contamination
at the Screw-Bone Interface during Spinal
Fusion: A Multicenter Study
Daksh Jayaswal1, Aakash Agarwal2, Boren Lin1,
Ashish Agarwal3, Amey Kelkar1, Gayane Saakyan1,
Hossein Elgafy1, Vijay Goel1, Arvind Jayaswal3,
Christian Schultz1, Anand Agarwal2
1

Departments of Bioengineering and Orthopedic Surgery, Colleges ofEngineering and Medicine, University of Toledo, Toledo, OH, USA
2
Spinal Balance Inc., Swanton, OH, USA
3
Primus Super Specialty Hospital, New Delhi, India

Purpose: The current data on postoperative infections inspinal fusion surgeries indicate occurrence in the range
of 2%–13%. These numbers might be underestimated due
to various reasons as cited in the publications, highlighting the magnitude of the issue. While current practiceincludes applications of vancomycin immediately before
closure, it is theoretically impossible to irrigate the screwbone interface following the surgery. Therefore, any
contamination associated with the pedicle screw before
implantation is permanent. This can be potentially harmful, as it can cause deep-bone infection, or hardware loosening at the screw-bone interface. This forms the basis for
improved monitoring and introduction of effective pre-

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Asian Spine J 2021;15(Supplement 1):S1-S177

ventive measures. The objective of this study was to assess
the bacterial contamination in current practices of pedicle
screw handling in spinal fusion surgeries and evaluate theefficacy of the novel method of using an intraoperative,sterile implant guard for screws against the same.
Methods: Two groups of pre-sterile individually packaged
pedicle screws, one incased in a sterile, protective guard(group 1: G) and the other without such a guard (group
2: NG), 31 samples in each group were distributed over
28 spinal fusion surgeries at five independent hospitals
groups. Each were loaded onto the insertion device by the
scrub tech and left on the sterile table. Twenty minutes
later, the lead surgeon who had just finished preparing
the surgical site, handles the pedicle screw, to check the fit
with the insertion device. Then, instead of implantation,
it was transferred to a sterile container using fresh sterile
gloves for bacterial analysis.
Results: The standard unguarded pedicle screws presented
bioburden in the range of 105 to 107 colonies forming units per screw, whereas the guarded pedicle screws
showed no bioburden. The bacteria genus identified from
cultures were Staphylococcus and Micrococcus, the twomost common genera reported in surgical site infection
cases.
Conclusions: The result of this study indicates that thecurrent processes related to handling of pedicle screws
leads to bacterial contamination of pedicle screws, andthereby the screw-bone interface. This can be potentiallyavoided by using a sterile guard, in which the screws aresterilely prepackaged until implantation. The authors advocate for this change in current practice to move towards
a safer, more economic practice.

PS-FP-7-23

Poor Nutritional Status and Chronic Kidney
Disease Might Be Risk Factors in Elderly
Patients with Pyogenic Spondylitis
Erina Yamada, Toshihiro Imamura, Yukihide Iwamoto
Department of Orthopaedic Surgery, Kyushu Rosai Hospital, Fukuoka,
Japan

Purpose: Faced with a super-aging society, infection is alife-threatening disease. The incidence of pyogenic spondylitis is not decreasing in our hospital, and relevant lit-

erature (PubMed) is increasing worldwide. In particular,
elderly patients are relatively frail; therefore, we hypothesized that the nutritional status is quite poor in patientswith pyogenic spondylitis. To examine the nutritional
status and relative factors in patients with pyogenic spondylitis.
Methods: We retrospectively reviewed 23 patients (16males, seven females) hospitalized with pyogenic spondylitis between 2018 and 2020 in Kyushu Rosai Hospital. To
confirm pyogenic spondylitis, magnetic resonance imaging or computed tomography was performed in addition
to laboratory tests. The mode of onset was evaluated using
the Kulowski classification. Since the infection was related
to a poor nutritional status and immunocompromised
host, the nutritional status was evaluated based on theControlling Nutrition Status (CONUT) score. As previously reported, chronic kidney disease (CKD) is associated with comorbid lifestyle-related diseases such as cardiovascular disease and diabetes mellitus. Such diseases,
especially in elderly individuals, may be associated witha low nutritional status. Therefore, we evaluated renal
function using the Cockroft and Gault (C-G) formula. We
statistically analyzed the correlation between the CONUT
score and C-G results.
Results: Regarding the patient demographics, the mean
age at the onset of pyogenic spondylitis was 70±13 years.
In our study, according to the Kulowski classification, 74%of the patients had subacute (n=11, 48%) or chronic- type(n=6, 26%) onset. C-G calculations revealed that 70% of
the patients had CKD worse than stage G3a. All the patients were classified into the CONUT-low group (≤2) or
CONUT-high group (≥3). The CONUT score was correlated with the C-G results (r=-0.52).
Conclusions: Since the CONUT score is based on theserum albumin level, total cholesterol level, and total lymphocyte count, the CONUT score may reflect malnutrition and the systemic inflammation status. Since pyogenic
spondylitis is an inflammatory disease, the malnutrition
status may further aggravate spondylitis. CKD is also
linked to the malnutrition status. Our study suggests thatpatients with pyogenic spondylitis potentially have malnutrition and CKD. Therefore, an active nutritional intervention may contribute to treatment in addition to theusual treatment for pyogenic spondylitis.

Asian Spine Journal
PS-FP-7-24

Evaluating Reprocessed Pedicle Screws:
Characterization of Contaminants and Efficiencyof the Process
Daksh Jayaswal1, Aakash Agarwal2, Amey Kelkar1,
Ashish Agarwal3, Gayane Saakyan1, Arvind Jayaswal3,
Anand Agarwal2
1

Departments of Bioengineering and Orthopedic Surgery, Colleges ofEngineering and Medicine, University of Toledo, Toledo, OH, USA
2
Spinal Balance Inc., Swanton, OH, USA
3
Primus Super Specialty Hospital, New Delhi, India

Purpose: Pedicle screws are almost synonymous with theterm spinal fusion. Processing of these implants is a multistep process that comes under the ambit of the sterilization
processing department, managing activities such as receiving contaminated implants, sterilizing them, and redistributing them in the facility. An efficient process across thedifferent steps is vital for the proper surgical managementof the patients, leading to avoidance of costly delays andsurgical site infection. The design of pedicle screws raises
a concern regarding the practicality of a repeated cleaning process, at the heart of which lies the manufacturer’s
instruction for cleaning and sterilization. The objective of
this study was to evaluate the nonmicrobial contaminantsprevalent on the pedicle screws used for spine surgery andthe underlying practice cause behind the source.
Methods: The study design consisted of two components:(1) evaluation of pedicle screws for presence of residual
nonmicrobial contaminants and (2) comparison of manufacturer prescribed guideline versus actual practice of thesteps and time required. The first component comprised arandomized selection of six pedicle screws and its assessment using optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, and Fouriertransform infrared spectroscopy. The second component
involved a detailed review of implant reprocessing guidelines and its applicability.
Results: Three types of contaminants were identified: corrosion, saccharide of unknown origin, and soap residue
mixed with and were mostly present at the interfaces withlow permeability. In addition, the data from tabulationof manufacturer’s guideline identified at least 19 disjoint
steps and a minimum of 19 man-hours required for reprocessing, whereas the real-time observation revealed
the reprocessing time of 1 hour 17 minutes.

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Conclusions: An interesting observation is that while weare seeing innovations across healthcare, the processes associated with reprocessing implants has stayed unaltered.
Our results showed corrosion, carbohydrate, fat, and soap
on reprocessed pedicle screw implants obtained from reprocessed implant sets in active clinical use. These results
indicate the cleanliness profile of reprocessed devices bothduring reprocessing and prior to sterilization. At par with
this, are the deficiencies in cleaning and inspection methodology prescribed by the manufacturers for cleaningthese single-use devices.

PS-FP-7-26

All-Posterior Approach in Surgical Managementof Thoracolumbar Tuberculosis: A Prospective
Randomized Study Comparing Posterior-Only
Stabilization versus Global Reconstruction
Rohit Akshay Kavishwar, Ajoy Prasad Shetty, S. Rajsekeran
Ganga Medical Center, Spine Surgery Department., Coimbatore, India

Purpose: Although no doubts exist regarding the surgicalindications for spinal tuberculosis, uncertainty still persists in deciding between posterior-only stabilization or
global reconstruction in thoracolumbar disease. We performed a prospective randomized study comparing these
two techniques and evaluated their safety and efficacy interms of clinic-radiological outcome parameters.
Methods: 58 patients with preliminary diagnosis of spinal
tuberculosis affecting thoracic and lumbar spine wererandomly allocated into two groups: group A (n=29):
posterior-only stabilization; group B (n=29): global reconstruction (posterior stabilization+anterior reconstruction
through a single stage all-posterior approach). Patient
demographic data, clinical and operative details, complications, and duration of hospital stay were recorded.
Radiological measurements included preoperative vertebral bone loss, Cobb’s angle, kyphosis correction, loss ofcorrection, angle loss rate, and fusion time. Functional
outcome measurements included Visual Analog Scale andOswestry Disability Index (ODI) scoring preoperatively
and at final follow-up. Neurological assessment was performed using American Spinal Cord Injury Association
impairment scale. Minimal follow-up period was 2 years.
Results: Group A had shorter surgical duration and better

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ODI score (p<0.05). Kyphosis correction was comparable
between two groups (p>0.05). Loss of correction and angle
loss rate were higher in group A, though not statisticallysignificant (p>0.05). All achieved bony fusion with no significant difference. Functional and neurological outcomes
showed improvement in both groups. Subgroup analysis
showed no significant difference between autograft andmetallic cage used for anterior reconstruction in group B.
Conclusions: Posterior-only stabilization and global reconstruction are equally effective in surgical management of
thoracolumbar tuberculosis, though global reconstruction
may result in better maintenance of kyphosis correction.

PS-FP-7-27

Development of Tuberculosis Spine Instability
Score (TSIS): An Evidence-Based and Expert
Consensus-Based Content Validation Study
Among Spine Surgeons
Kaustubh Ahuja, Syed Ifthekar, Samarth Mittal,
Gagandeep Yadav, Pankaj Kandwal
All India Institute of Medical Sciences, Rishikesh

Purpose: Over the years, a number of authors have useddifferent definitions of instability in tuberculosis (TB)
spine. However, no clear consensus exists to define instability in TB spine. Currently, diagnosis of instability is primarily experience-based which may lead to considerable
variability and misdiagnosis in the hands of a relatively
in-experienced spine surgeon. Considering the potential
complications this entity entails, a universally accepted
scoring criteria is very important for accurate and uniform diagnosis of instability in TB spine. Questions: (1)What are the factors predicting instability in TB spine? (2)To develop a novel scoring system for diagnosing instability in tuberculosis (TB) spine using evidence from preexisting literature followed by an expert-panel consensus
for validating the content.
Methods: The development of TB spine instability score(TSIS) followed a two-step process: one designing the instrument and the other obtaining judgmental evidence. The
instrument design included domain specification, item identification and allotment and finally instrument construction.
For the second part of judgmental evidence a panel of experts was appointed to make appropriate modifications andcontent validation for finalizing the scoring instrument.
Results: The comprehensive scoring criteria to diagnose
instability in TB spine was approved after three rounds ofexpert panel discussions and comprised of age, locationof the lesion, pain, degree of kyphosis, vertebral body loss,
involvement of posterior spinal elements, multifocal contiguous disease, and presence of intervertebral or paraspinal abscess. All the factors were found to have index
of content validation more than 0.75 after final round ofpanel discussion. The scores for each item and category
specification were based on the findings of systematic review further refined by expert-panel.
Conclusions: TSIS is a comprehensive scoring system integrating demographic, anatomical, clinical and radiologicalfactors aimed at diagnosing instability in TB spine. The classification determines indications for surgical stabilization inpatients with TB spine, especially with no or little neurological deficit. However, it also aids surgical decision making
when used in context with other key elements such as neurological deficit, patient health factors and osteoporosis.

PS-FP-8-1

The Characteristics of the Young Patientswith Cervical Ossification of the PosteriorLongitudinal Ligament of the Spine: A
Multicenter Cross-Sectional Study
Kanji Mori1,2, Toshitaka Yoshii2,3, Takashi Hirai2,3,
Jun Hashimoto2,3, Narihito Nagoshi2,4, Kazuhiro Takeuchi2,5,
Keiichi Katsumi2,6, Satoshi Maki2,7, Masaya Nakamura2,4,
Morio Matsumoto2,4, Atsushi Okawa2,3,
Yoshiharu Kawaguchi2,8, JOSL Members2
1

Department of Orthopaedic Surgery, Shiga University of Medical Science, Otsu,
Japan
2
Japanese Organization of the Study for Ossification of Spinal Ligament (JOSL),
Tokyo, Japan3
Department of Orthopedic Surgery, Tokyo Medical and Dental University,
Tokyo, Japan
4
Department of Orthopedic Surgery, Keio University, School of Medicine, Tokyo,
Japan
5
National Hospital Organization Okayama Medical Center, Okayama, Japan
6
Department of Orthopedic Surgery, Niigata University Medical and Dental
General Hospital, Niigata, Japan
7
Department of Orthopedic Surgery, Chiba University Graduate School of
Medicine, Chiba, Japan
8
Department of Orthopedic Surgery, Faculty of Medicine, University of
Toyama, Toyama, Japan

Purpose: Ossification of the posterior longitudinal liga-

Asian Spine Journal
ment of the spine (OPLL) is characterized by heterotopic
bone formation in the posterior longitudinal ligamentof the spine. Although the patients with OPLL are morecommon in the 60s and 70s, we know that there aremarkedly young patients (e.g., early 40s). However, to thebest of our knowledge, there is few reports characterize
young patients with cervical OPLL in terms of the imaging features, subjective symptoms, and activities of dailyliving (ADL) problems. The aim of the present study is tocharacterize young patients with cervical OPLL in termsof the imaging features, subjective symptoms, and ADL
problems.
Methods: This is the multicenter cross-sectional study.
Two hundred and thirty-seven Japanese symptomatic patients with cervical OPLL confirmed by standard X-rays
collected from 16 institutions belonging to the JapaneseMulticenter Research Organization for Ossification of
the Spinal Ligament formed by the Japanese Ministry of
Health, Labor and Welfare were recruited. Whole spine
computed tomography data as well as demographic datasuch as age, gender, patients-based evaluations, and the36-item Short Form Health Survey (SF-36) were evaluated.
Results: Young group (≤45 years old) consisted of 23 patients (eight females and 15 males), accounting for 9.7% of
the total. Their characteristics were high body mass index(BMI), significant involvement of trauma in the onset anddeterioration of symptoms, and the predominance of thoracic OPLL. The patient-based evaluations did not show asignificant difference between the young and non-younggroups, or between the genders in the young group except
for bodily pain (BP) of SF-36. Female patients in younggroup had significantly low BP score of SF-36 than that ofmale in young group.
Conclusions: Characteristics of young patients with cervical OPLL were high BMI, significant involvement of
trauma in the onset and deterioration of symptoms, lower
BP score of SF-36 in female, and the predominance ofthoracic OPLL.

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PS-FP-8-2

Reduction and Fusion of Thoracic Ossificationof the Posterior Longitudinal Ligament after
Posterior Decompression with Instrumented
Fixation by Pedicle Screw Insertion into All
Ossified Vertebrae
Osamu Kawano, Takeshi Maeda, Hiroaki Sakai,
Muneaki Masuda, Yuichiro Morishita, Tetsuo Hayashi,
Kensuke Kubota, Kazu Kobayakawa, Kazuya Yokota,
Hironari Kaneyama
Department of Orthopedic Surgery, Spinal Injuries Center, Fukuoka, Japan

Purpose: To investigate the reduction and fusion in preoperative discontinuous ossification of the posterior longitudinal ligament (OPLL) after posterior decompression
with instrumented fixation by pedicle screw insertion into
all ossified vertebrae in patients with thoracic OPLL (TOPLL).
Methods: Twenty-three patients with T-OPLL who underwent posterior decompression with instrumented fixation
by pedicle screw insertion into all ossified vertebrae wereanalyzed based on sagittal multi-planner reconstructioncomputed tomography (MPR-CT) images obtained justbefore surgery and at a follow-up examination. Pedicle
screws were inserted in all vertebral bodies within therange of ossification. Screw insertion was carried out prior
to decompression and temporary rod fixation was constantly conducted on one side at the time of the decompression procedure. Changes in the thickness of the OPLL
were investigated using sagittal MPR-CT images obtained
just before surgery and at a follow-up examination. It wasalso investigated whether or not bone fusion of OPLL was
obtained in the preoperative discontinuous OPLL at thetime of follow-up.
Results: Bone fusion of the OPLL was observed in all cases. The thickness of the OPLL showed an average reduction of 1.14 mm. The average reduction rate of the OPLL
was 15.0%. There was a significant correlation between the
reduction in thickness of the OPLL and the pre-operative
thickness of the OPLL. The results indicate that the OPLL
can be expected to be reduced by approximately 15% of
the pre-operative thickness of the OPLL.
Conclusions: Pedicle screw fixation into all ossified vertebrae reduced the thickness of ossification by approximately 15% in comparison to the thickness of ossification

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prior to surgery and resulted in bone fusion at the discontinuous ossification in 100% of all cases. Strong fixation
using a pedicle screw system not only rapidly improved
the dynamic factors but also gradually improved the static
compression factors of the affected spinal cord.

PS-FP-8-3

Does Diabetes Affect the Surgical Outcomes inCases with Cervical Ossification of the PosteriorLongitudinal Ligament? A Multicenter Study
from Asia Pacific Spine Study Group
Narihito Nagoshi1, Kota Watanabe1, Masaya Nakamura1,
Morio Matsumoto1, Nan Li2, Sai Ma2, Da He2, Wei Tian2,
Hyeongseok Jeon3, Jong Joo Lee3, Keung Nyun Kim3,
Yoon Ha3, Kenny Kwan4, AKP Cheung4
1

Department of Orthopaedic Surgery, Keio University School of Medicine,Tokyo, Japan2
Department of Spine Surgery, Beijing Jishuitan Hospital, the 4th Teaching
Hospital of Peking University, Beijing, China
3
Department of Neurosurgery, Yonsei University, Seoul, Korea
4
Department of Orthopaedics and Traumatology, LKS Faculty of Medicine,
The University of Hong Kong, Hong Kong

Purpose: It is well known that morbidity rate of diabetes
mellitus (DM) is higher in the patients with ossificationof the posterior longitudinal ligament (OPLL). Because
the DM inflicts adverse effect on the microvascular andnervous system, a concern remains about the relation ofthis metabolic pathology with surgical outcomes for thecervical OPLL. The purpose of this study is to evaluate thesurgical outcomes of cervical OPLL in patients who had
DM.
Methods: This retrospective study included 253 patientswith clinically and radiographically confirmed cervical
OPLL who were treated at four institutions in three countries (China, Korea, and Japan) between 2010 and 2016.
All patients were followed for at least 2 years. Demographic, imaging, and surgical information were collected, andpatients were evaluated using cervical Japanese Orthopaedic Association (JOA) scores and the Visual Analog Scale(VAS) for the neck.
Results: Forty-seven patients had the DM and showed
higher prevalence of hypertension (p=0.01) and cardiovascular diseases (p<0.01). Although they presented worse
preoperative JOA scores compared to non- DM patients(10.5±3.1 vs. 11.8±3.2, p=0.01), comparable neurologic
recovery was achieved in the DM group at final followup regardless of preoperative hemoglobin A1c levels(13.9±2.9 vs, 14.2±2.6, p=0.41). There was no significant
difference in the result of VAS at pre- and post-surgery.
Regarding perioperative complications, however, the caseswith DM presented higher frequency of C5 palsy (14.9%
vs. 5.8%, p=0.04). Similar trend was observed when surgical procedure was limited to laminoplasty.
Conclusions: This is the first multicenter Asian study toevaluate the impact of DM on cervical OPLL patients.
Even in the DM cases, surgical results were favorable
regardless of preoperative hemoglobin A1c levels or operative procedures. However, caution is warranted for theoccurrence of C5 palsy after surgery in the DM patients.

PS-FP-8-5

Comparison of Decompression Alone andDecompression Plus Fusion for Thoracic
Myelopathy Due to Ossification of theLigamentum Flavum
Yuichi Ono1, Naohisa Miyakoshi2, Yuji Hatakeyama1,
Yoichi Shimada2
1

Department of Orthopedic Surgery, Akita Red Cross Hospital, Akita, Japan
Department of Orthopedic Surgery, Akita University Graduate School of
Medicine, Akita, Japan
2

Purpose: The aim of this study was to clarify the clinicaloutcomes in patients undergoing decompression alone
versus decompression with fusion for ossification of theligamentum flavum (OLF) of the thoracic vertebrae.
Methods: Thirty-seven patients who underwent surgicaltreatment for thoracic myelopathy between 2010 and 2015at multiple centers were included in this analysis. Surgicaltreatment included either decompression or a decompression plus fusion procedure. We investigated the patients’characteristics and pre- and postoperative thoracic myelopathy using the Japanese Orthopaedic Association(JOA) score. Differences in these factors between decompression and decompression plus fusion were examined.
Results: Decompression alone was performed in 18 cases(48.6%), and decompression plus fusion was performed
in 19 cases (51.4%). The decompression plus fusion group
showed greater blood loss and a longer operative time

Asian Spine Journal
than the decompression group. Decompression plus fusion was significantly more frequently performed inpatients with thoracic OLF combined with ossificationof the posterior longitudinal ligament (OPLL). The preoperative JOA score was lower and JOA recovery rate at final
follow-up was significantly higher in cases treated withdecompression plus fusion. There were no significant differences between the two groups in the rate of intraoperative complications and reoperation, number of OLF levels,
preoperative duration of symptoms, and final JOA score.
Conclusions: Decompression plus fusion was performed
more often for OLF patients with severe thoracic myelopathy and OPLL. However, since surgical invasivenessis greater with decompression plus fusion, selection of thesurgical procedure should be carefully considered in individual cases.

PS-FP-8-7

Factors Having Significant Relationshipwith Postoperative Neck Pain Deterioration
for Cervical Ossification of the PosteriorLongitudinal Ligament: Prospective RegistryStudy
Masao Koda1,2, Toshitaka Yoshii2,3, Satoru Egawa2,3,
Kenichiro Sakai2,4, Yukihiro Nakagawa2,5, Kanichiro Wada2,6,
Keiichi Katsumi2,7, Atsushi Kimura2,8, Yukitaka Nagamoto2,9,Yasushi Oshima2,10, Masahiko Takahata2,11, Kanji Mori2,12,
Takashi Kaito2,13, Sho Kobayashi2,14, Satoshi Kato2,15,
Shiro Imagama2,16, Yoshiharu Kawaguchi2,17,
Morio Matsumoto2,18, Atsushi Okawa2,3, Masashi Yamazaki1,2
1

Department of Ortrhopaedic Surgery, University of Tsukuba, Tsukuba,
Japan
2
Japanese Multicenter Research Organization for Ossification of the Spinal
Ligament, Tokyo, Japan3
Department of Orthopaedic Surgery, Tokyo Medical and Dental University,
Tokyo, Japan
4
Department of Orthopaedic Surgery, Saiseikai Kawaguchi General Hospital,
Kawaguchi, Japan
5
Department of Orthopaedic Surgery, Wakayama Medical University
Kihoku Hospital, Wakayama, Japan
6
Department of Orthopaedic Surgery, Hirosaki University Graduate Schoolof Medicine, Hirosaki, Japan
7
Department of Orthopaedic Surgery, Niigata University Medicine andDental General Hospital, Niigata, Japan
8
Department of Orthopaedics, Jichi Medical University, Shimotsuke, Japan
9
Department of Orthopaedic Surgery, Osaka Rosai Hospital, Sakai, Japan10
Department of Orthopaedic Surgery, Faculty of Medicine, The University ofTokyo, Tokyo, Japan

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11

Department of Orthopaedic Surgery, Faculty of Medicine and Graduate
School of Medicine, Hokkaido University, Sapporo, Japan
12
Department of Orthopaedic Surgery, Shiga University of Medical Science,Otsu, Japan
13
Department of Orthopedic Surgery, Graduate School of Medicine, Osaka
University, Osaka, Japan
14
Department of Orthopedic Surgery, Hamamatsu University School of
Medicine, Hamamatsu, Japan
15
Department of Orthopaedic Surgery, Graduate School of Medical Sciences,
Kanazawa University, Kanazawa, Japan
16
Department of Orthopedic Surgery, Nagoya University Graduate School of
Medicine, Nagoya, Japan17
Department of Orthopedic Surgery, Faculty of Medicine, University of
Toyama, Toyama, Japan18
Department of Orthopaedic Surgery, School of Medicine, Keio University,
Tokyo, Japan

Purpose: Postoperative neck pain had been reported as
one of the problematic postoperative complications ofsurgery for cervical ossification of the posterior longitudinal ligament (OPLL). The aim of the present study was toelucidate factors having significant correlation with postoperative deterioration of neck pain in cervical OPLL.
Methods: The present registry included 478 patients who
underwent cervical spine surgery for myelopathy caused
by cervical OPLL. We excluded the patients who lacks
preoperative neck pain evaluation. Thus, we included 438
cervical OPLL patients. Neck pain was evaluated with
Visual Analog Scale (VAS, 0–100 mm) preoperatively, 6months, and 2 years after surgery. Postoperative neck pain
deterioration was defined as 20 mm or more increase of
VAS neck pain. Patient factors including age at surgery,sex, body mass index, disease duration, and diabetes mellitus were collected. Neurological status was assessed withJapanese Orthopedic Association score for evaluating
cervical myelopathy. Imaging factors were analyzed as followings: types of OPLL, canal narrowing rate, postoperative change of C2–7 angle, change of C2–7 range of motion, and spinal cord signal intensity change in magnetic
resonance imaging T2 weighted image. Surgical factors
including surgical procedures (laminoplasty, posterior
decompression with instrumented fusion [PDF], anterior
decompression and fusion [ADF] and anteroposterior
decompression and fusion [A-P]) and number of levels
fused were evaluated. We analyzed the influence of abovementioned factors on postoperative neck pain deterioration.
Results: Six months after surgery, 51 cases (11.6 %)showed postoperative neck pain deterioration, whereas
remaining 437 cases (88.4%) showed no deterioration andS130

Asian Spine J 2021;15(Supplement 1):S1-S177

76 cases (17.4 %) showed postoperative neck pain deterioration 2 years after surgery. Amongst fifty cases showing postoperative neck pain deterioration 6 months after
surgery, 23 cases showed attenuation of neck pain and remaining 27 cases showed no recovery of neck pain. Thus,
neck pain deterioration in 49 out of 76 cases occurredfrom 6 months to 2 years after surgery. Six months after
surgery, the rate of neck pain deterioration in laminoplasty and PDF groups was significantly higher than that in
ADF and A-P groups. Two years after surgery, levels fused
was significantly correlated with neck pain deterioration.
Conclusions: Posterior approach significantly associatedwith neck pain deterioration 6 months after surgery andnumber of levels fused significantly associated with neckpain deterioration 2 years after surgery.

Conclusions: A lot of cases of thoracic OYL were not able
to be diagnosed accurately. Hyperactive tendon reflexes
in the lower limbs were seen in only about half. In somecases, lower limb symptoms worsen when the lower backis extended, which is mistaken for lumbar spine disease.
In fact, there is a tendency to overlook thoracic OYL
when the patient had lumbar spinal stenosis. Because ossification compresses the spinal cord from posterior, it isalso characterized by the tendency for posterior cord syndrome to occur.

PS-FP-8-8

Kohei Kuroshima, Koki Uno, Masaaki Ito, Teppei Suzuki

PS-FP-9-3

Posterior Spinal Fusion with Pedicle Screws for
Atlantoaxial Instability in Children
Department of Orthopaedic Surgery, Kobe Medical Center, Kobe, Japan

Characteristics of Ossification of the Ligamentum
Flavum of the Thoracic Spine
Masatoshi Morimoto, Kazuya Kijima, Kiyoshi Yagi,
Fumitake Tezuka, Kazuta Yamashita, Koichi Sairyo
Tokushima University Graduate School, Tokushima, Japan

Purpose: The pathophysiology of thoracic ossification of
the ligamentum flavum is not well understood and is often
overlooked. Especially at the lower thoracic spine level, it
is often difficult to distinguish from lumbar spinal disease.
Therefore, we investigated the symptoms of ossification of
the ligamentum flavum (OYL) at the lower thoracic spinelevel, which was surgically treated at our hospital.
Methods: The subjects were 21 patients (12 males, nine
females; average age, 73 years) treated from 2020 to 2021.
All patients underwent posterior decompression and fixation. The rate the previous doctor was able to diagnose as
thoracic OYL accurately and the symptoms and physicalexamination of OYL were evaluated.
Results: The rate the previous doctor was able to diagnose
as thoracic OYL were 33%. The subjective symptoms were
low back pain in 24%, leg pain in 48%, numbness in thelower limbs in 67%, and unsteady on the legs in 48%. In
addition, 43% of cases had worsening symptoms due tosupine position or lumbar extension. Neurological findings were hyperactive deep tendon reflexes of lower limb
in 57%, Romberg sign in 33%, and heel knee test in 48%.

Purpose: Surgical treatment of atlantoaxial instability(AAI) in children is still a challenge due to tiny vertebrae
and the high complication rate which has been reported
since several decades ago. However, surgical technique,perioperative management, spinal implant, and perioperative radiographic evaluations have made remarkable progress. The purpose of this study is to report complicationsof posterior fusion for AAI in children and to evaluate thescrew placement accuracy.
Methods: A total of 31 pediatric patients underwent primary posterior fusion for AAI from January 2004 to December 2017 (18 boys, 13 girls; mean age, 7.4 years) andwere followed for an average of 7.4 years. The pathology
included 18 Down syndrome, three skeletal dysplasia, and
one Coffin-Siris syndrome. Nine cases were idiopathic
and all the cases had os odontoideum. C1–C2 or C1–
C3 fusions were performed in 22 patients and occipitocervical fusions in nine patients. We analyzed their pasthistory, operating time, estimated blood loss (EBL), andperioperative and intraoperative complications. Postoperative computed tomography was used to assess screw
accuracy using the established Neo classification (grade 0:
no perforation, grade 1: perforation <2 mm, grade 2: perforation ≥2 and <4 mm, grade 3: perforation ≥4 mm).
Results: Seventeen patients had histories of cardiovascular diseases, but their cardiac functions were evaluated totolerate general anesthesia. The mean operating time wasAsian Spine Journal
260.7±71.2 minutes and the mean EBL was 144.2±122.7
mL. Complications related to the operation occurred ineight patients (25.8%). They included one hydrocephalus
due to dural tear, one bone graft donor site deep infection, two temporary neurological deficit which were fully
recovered, one superficial infection, and four implantloosening. Patients underwent 108 screw fixations (43C1 lateral mass screws, 50 C2 pedicle screws, seven C3
pedicle screws, and eight C2 laminar screws). A total of 34(79.1%) of the 43 C1 lateral mass screw placements werecategorized as grade 0, 7 (16.3%) were grade 1, 1 (2.3%)
was grade 2, and 1 (2.3%) was grade 3. A total of 44 (77.2%)of the 57 pedicle screw placements were categorized as
grade 0, 11 (19.3%) were grade 1, 0 were grade 2, and 2(3.5%) were grade 3.
Conclusions: The complication rate of upper-cervical fusion
in children was still high. However, the placement of screws
was almost accurate and safe even for tiny vertebrae andbone pathology. There seemed to be no reason to avoid surgical intervention to upper-cervical instability in children.

PS-FP-9-4

Biologic Agents Preserve the C-2 Pedicle
in Patients with Rheumatoid Arthritis: A
Comparative Imaging Study Using ThreeDimensional Computed Tomography
Takuya Obo, Takashi Fujishiro, Masahiro Mizutani,
Toma Yano, Sachio Hayama, Yoshiharu Nakaya,
Atsushi Nakano, Masashi Neo
Department of Orthopedic Surgery, Osaka Medical College, Takatsuki,
Japan

Purpose: To investigate whether biologic agents (BAs)reduce a narrow C-2 pedicle screw (PS) trajectory, which
is often a key stabilizer in surgical treatment, in patientswith rheumatoid arthritis (RA).
Methods: A total of 100 RA patients treated with and without BAs (BA [+] group [n=50] and BA [-] group [n=50]),
respectively, were included in the present study. Computed
tomography (CT) images of their cervical spine, including
C-2, were analyzed. The maximum screw diameter (MSD)
at C-2 that could be inserted without breaching the cortex,
measured on three-dimensional images using a CT-basednavigation system, was compared between the groups

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with and without BA administration. Furthermore, thedestruction of the atlantoaxial joint was examined using
CT images. The risk factors for a narrow C-2 pedicle were
elucidated among the patients treated with BAs.
Results: The pedicle in the BA (+) group had a significantly larger C-2 MSD than the BA (-) group (6.00 mm vs. 5.13mm, p<0.001), with less destruction of the atlantoaxial
joint. Among the BA (+) group, a longer period until the
initial administration of BAs and RA disease duration
were associated with a narrow C-2 pedicle.
Conclusions: This study suggests that BAs can maintainthe trajectory for C-2 PS, which acts as a key stabilizer insurgical management for rheumatoid cervical spine, by
halting the destruction of the atlantoaxial joint. Early introduction of BAs can be especially important to preventthe narrowing of the C-2 pedicle.

PS-FP-9-5

Non-traumatic Atlantoaxial Rotatory Fixationin an Adult Patient Treated by a Closed Reduction
under General Anesthesia in Chronic Phase
Norihiro Isogai1,2, Kenshi Daimon1,3, Yutaka Sasao1,2,
Shigeto Ebata1,3, Haruki Funao1,2,3, Ken Ishii1,2,3
1

Department of Orthopaedic Surgery, School of Medicine, International
University of Health and Welfare (IUHW), Otawara, Japan2
Department of Orthopaedic Surgery, International University of Health andWelfare (IUHW) Mita Hospital, Tokyo, Japan3
Department of Orthopaedic Surgery, International University of Health andWelfare (IUHW) Narita Hospital, Narita, Japan

Purpose: Atlantoaxial rotatory fixation (AARF) is a common condition in the pediatric population. The majorityof acute AARF cases in the pediatric population can betreated by non-surgical treatment. In contrast, AARF is
an extremely rare condition in the adult population. The
therapeutic management for adult AARF is controversial,
and there have been no reports of non-traumatic AARF in
adult patients. We experienced the case of non-traumaticand chronic AARF in an adult patient treated by a closed
reduction under general anesthesia.
Methods: A 42-year-old female suffered from a severeneck pain and irreducible cervical rotation after waking
up. She visited a previous hospital 18 days after onset andwas admitted for 3 weeks to undergo Glisson’s head halter
traction. However, no improvement was observed, and theS132

Asian Spine J 2021;15(Supplement 1):S1-S177

patient was subsequently referred to our hospital 2 months
after onset. She exhibited a typical cock-robin position. Herneck remained in a fixed rotated position to the left, andher neck movement to the right side was severely restricted. She denied any history of trauma, infectious diseases,
psychiatric diseases, or surgeries related to her cervicalspine. The cervical radiographs and computed tomography(CT) scans revealed torticollis to the right and C1 rotation
with normal atlantodental interval. There were no obvious
fractures, ligament injury, or any other inflammatory findings in CT scans and magnetic resonance imaging. There
was no C2 facet deformity or C1–C2 bony union on threedimensional CT images in the plane position. According
to her radiographs and CT scans, a diagnosis of Fieldingclassification type I, Pang’s classification type 2, and Ishii’s
grade I AARF was confirmed.
Results: She eventually underwent closed reduction undergeneral anesthesia. The operator held her mandible withhis thumbs and her neck with his other fingers, provided
careful traction in the cephalic direction, and rotated herneck gradually to the right while palpating for crepitus.
Her neck was fully rotated to the right after 10 minutesof manipulation, and the reduction was confirmed byfluoroscopy. Immediately after waking up from generalanesthesia, her neck pain and irreducible cervical rotation
dramatically improved without any complications suchas neurological deficit or fractures. Two years after closed
reduction, she had no neck pain or recurrence of limited
cervical rotation.
Conclusions: A closed reduction under general anesthesia
for non-traumatic AARF in adult patients might be an effective treatment option, even for chronic cases or intractable cases by traction treatment.

PS-FP-10-1

The Ipsilateral Epiphyseal and Central Endplate
Hounsfield Units Accurately Predicts
Intraoperative Endplate Violation and Delayed
Cage Subsidence with Oblique LateralInterbody Fusion
Jason Pui Yin Cheung1, Hao Wu1, Teng Zhang1, Zhi Shan2,
Xuyang Zhang2, Junhui Liu2, Shunwu Fan2,
Fengdong Zhao2
1

Department of Orthopaedics and Traumatology, The University of Hong
Kong, Hong Kong
2
Department of Orthopaedics, Sir Run Run Shaw Hospital, Zhejiang
University School of Medicine, Hangzhou, China

Purpose: There are favorable results with oblique lateralinterbody fusion (OLIF) to achieve indirect decompression. Some of the most dreaded complications include
intraoperative endplate violations and delayed cage subsidence. The endplate plays an important role in distributing compressive load across a functional spinal unit. The
Hounsfield units (HUs) can provide detailed information
regarding bone quality across endplates at surgical levels.
We aimed to investigate the risk factors for intraoperative endplate violations and delayed cage subsidence after
OLIF surgery.
Methods: A total of 61 consecutive patients (mean age,65.1±9.5 years; 107 segments) who underwent OLIF withor without posterior instrumentation from May 2015 toApril 2019 were studied. Intraoperative endplate violation was defined as more than 2 mm collapse of the cage
into the endplate of the adjacent vertebral body on sagittal
reconstructed computed tomography images immediate
postoperatively. Delayed cage subsidence was evaluatedusing lateral radiographs and defined as more than 2 mm
migration of the cage into the adjacent vertebral endplate
at 1-month follow-up or later. As potential contributors,bone mineral density, number of surgical levels, preoperative and postoperative disc height and Hounsfield units(HUs) at different regions of the endplate were obtained
along with other demographic factors.
Results: Total postoperative cage subsidence was identified in 45 surgical levels (42.0%) in 26 patients (42.6%) up
till postoperative 1-year follow-up. These consisted of 25
intraoperative endplate violation segments (23.4%) and
20 levels (18.7%) with delayed cage subsidence. Low HUvalue at the ipsilateral epiphyseal ring was an independent

Asian Spine Journal
risk factor for intraoperative endplate violation (p=0.01)
with a cut-off value of 326.21 HUs (sensitivity 79.0%,
specificity 77.3%). Low HU values at the central endplate
had a significant correlation with delayed cage subsidence in stand-alone cases (p=0.01) with a cut-off value of
296.42 HUs (sensitivity 76.9%, specificity 76.6%).
Conclusions: HUs of the endplate are good predictors for
intraoperative endplate violation and cage subsidence
since they can represent the regional bone quality of theendplate in contact with the implant. These are importantparameters for consideration preoperatively to plan forcage sizes and posterior instrumentation.

PS-FP-10-3

A New Full Endoscopy System and Intradiscal
Irrigator Combined with a Novel AnnularRepair Device for the Treatment of Lumbar
Disc Herniation
En Song1, Ji Zheng Li2, Yan Lin Li1, You Qing Huang3,
Fan Bing Li2, Xiao Feng Yuan4, Xue Song Chen5,
En Bin Wang6, Xian Guang Yang1, Yao Yu Xiang1
1

Department of Sports medicine, The First Affiliated Hospital of Kunming
Medical University, Kunming, China
2
Department of Orthopedics, First Clinical Medical College of Yunnan
University of Traditional Chinese Medicine, Kunming, China
3
Department of Pain, The Second Affiliated Hospital of Kunming Medical
University, Kunming, China
4
Department of Orthopedics, The First People’s Hospital of Kunming,
Kunming, China
5
Department of Pain, The Fourth People’s Hospital of Kunming, Kunming,
China
6
Department of Orthopedics, Baoshan Hospital of Traditional Chinese
Medicine, Shanghai, China

Purpose: The aim of this study was to determine thetechnical feasibility, clinical safety, and efficacies of a newtransforaminal approach endoscopic system for the treatment of lumbar disc herniation. The new serial therapeutic system includes a novel endoscopy system, an intradiscal irrigator, and a full endoscopic annular repairment
device.
Methods: From October 2017 to June 2019, we enrolled
16 patients 21 to 46 years of age, with imaging confirmation of single-level disk herniation between L3 and L5 (L3/
L4 level, three cases; L4/L5 level, eight cases; L5/S1 level,
five cases) with disk height ≥5 mm, and who failed ≥6

S133

weeks of nonsurgical treatment. Magnetic resonance imaging with T1- and T2-weighted axial and sagittal images,
multiplanar computed tomography, and flexion/extension
X-rays were performed. All patients had lumbar radiculopathy with positive straight leg raise or femoral stretch
test. All patients underwent transforaminal approachendoscopic discectomy use the novel endoscopic system,
after discectomy we used the novel irrigator inserted into
the tears of annulus fibrosus for intradiscal irrigation,then we used a novel full endoscopic annular repairment
device close the annular defects which was an automatic
stitching and tying device. The Visual Analog Scale (VAS)
and Oswestry Disability Index (ODI) were observed before operation and at 1 day, 1 month, 6 months, and last
follow-up after the operation.
Results: The procedure was successfully performed in allcases. Average operation time was 95 minutes. Average
blood loss was 15.3±3.8 mL. At last follow-up (9.6±1.7
months), all patients experienced a minimally clinicallyimportant improvement of their VAS for ipsilateral leg
pain, which improved from 7.3±0.2 preoperatively to
1.8±0.3 postoperatively (p=0.001). The ODI improved
from 52±3.8 preoperatively to 20.1±4.4 at last follow-up(p=0.001). There was no postoperative complication andrecurrence of disc herniation.
Conclusions: Early results showed the use of the newtransforaminal approach endoscopic irrigation and annular repairment system for the treatment of lumbar discherniation are beneficial for short term outcomes demonstrating reduction in symptomatic disc reherniation withlow postoperative complication rates. Long-term studies
are required to further investigate the efficacy of such devices.

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PS-FP-10-4

A Novel Annular Repair Technique Combinedwith Platelet-Rich Plasma Intradiscal Injection:
A New Serial Therapeutic Model for the Treatment
of Lumbar Disc Herniation
En Song1, Ji Zheng Li2, Yan Lin Li1, En Bin Wang3,
Fan Bing Li2, You Qing Huang4, Xiao Feng Yuan5,
Xue Song Chen6, Xian Guang Yang1, Yao Yu Xiang1
1

Department of Sports medicine, The First Affiliated Hospital of Kunming
Medical University, Kunming, China
2
Department of Orthopedics, First Clinical Medical College of Yunnan
University of Traditional Chinese Medicine, Kunming, Kunming, China
3
Department of Orthopedics, Baoshan Hospital of Traditional Chinese
Medicine, Shanghai, China
4
Department of Pain, The Second Affiliated Hospital of Kunming Medical
University, Kunming, China
5
Department of Orthopedics, The First People’s Hospital of Kunming,
Kunming, China
6
Department of Pain, The Fourth People’s Hospital of Kunming, Kunming,
China

Purpose: This study aims to evaluate the clinical safety andefficacies of a novel microdiscectomy annular repairment
technique combined with autologous platelet-rich plasma(A-PRP) intradiscal injection for the treatment of lumbar
disc herniation.
Methods: From July 2017 to December 2018, this study
recruited 15 patients with lumbar disc herniation (L4/5,
four cases; L5/S1, 11 cases) who underwent tubular microdiscectomy and used a novel annulus fibrosus repairment device close the annular defects which was an automatic stitching and tying device. The patients underwent
A-PRP 2.1±0.2 mL intradiscal injection 1 week, 1 month,and 2 month after microdiscectomy annular repair surgery. The pre- and postoperative neurological function
and pain status were evaluated by the Visual Analog Scale(VAS) score and the Oswestry Disability Index (ODI).
The assessment also data including operation time, thequantity of bleeding, and intraoperative and postoperativecomplications were recorded. Patients were followed up atintervals of preoperative, postoperative 1 week, 1 months,
3 months, and last follow-up.
Results: The procedure was successfully performed in
all cases. No case required conversion to an open procedure. The mean age of patients was 36.6 years. Average
operation time was 85 minutes, Average blood loss was
35.3±6.2mL. The preoperative symptoms were alleviatedsignificantly after surgery. All the standardized measures
improved significantly. At the last follow-up, including
VAS score (7.9±1.2 to 1.1±0.5, p<0.001) and ODI (75.3 to
9.6, p<0.001). There was no postoperative complication
and recurrence of disc herniation.
Conclusions: Early results showed the use of the novel annular fibrosus repairment technique and PRP intradiscal
injection are beneficial for short-term outcomes demonstrating reduction in symptomatic disc reherniation withlow postoperative complication rates. Long-term studies
are required to further investigate the efficacy of suchdevices. Direct mechanical annular repair and A-PRP biological therapy may promote degenerative intervetebral
disc regeneration and remodeling after minimally invasive
spine surgical discectomy.

PS-FP-10-5

Overcorrection of Fractured Vertebrae Increases
the Incidence of Adjacent Fractures After
Balloon Kyphoplasty: A Retrospective Study
Keiichiro Iida, Hirokazu Saiwai, Akinobu Matsushita,
Kenichi Kawaguchi, Yoshihiro Matsumoto,
Yasuharu Nakashima
Department of Orthopaedic Surgery, Faculty of Medical Sciences, Kyushu
University, Fukuoka, Japan

Purpose: There are reports that the restoration height offractured vertebrae relates to the incidence of adjacent
fractures when kyphoplasty is performed. However, thepossible correction amount may be influenced by the instability of the fractured vertebra. Consideration of the relationship between vertebral instability and the degree ofcorrection is necessary to investigate whether the correction amount by kyphoplasty contributes to the incidenceof adjacent fractures. This study aimed to investigate
whether the correction amount by kyphoplasty is associated with the incidence of adjacent vertebral fractures.
Methods: Data from 61 patients without and 25 patientswith adjacent vertebral fractures at 6 months after balloon kyphoplasty (BKP) were retrospectively analyzed.
We compared age, sex, body mass index, site of the fracture, existence of past vertebral fracture, kyphosis angleof the fractured vertebra, fractured vertebral instability,
corrected angle, corrected height, cement amount, andAsian Spine Journal
cement leakage between the groups. A linear regression
model was used to determine the relationship between
vertebral instability and corrected angle or height and to
divide patients into the overcorrection and undercorrection groups. The patients above the regression line with
95% confidence interval were determined as having an
overcorrection while those under were determined to beundercorrected. The incidence rate of adjacent fractures
was compared between these two groups.
Results: Fractured vertebral instability and correctedamount were detected as risk factors for adjacent fractures(p<0.01). The corrected angle and height correlated withfractured vertebral instability, ρ=0.6447 and 0.4909, respectively. Vertebral fractures overcorrected for instability
led to a higher incidence rate of adjacent fractures (42.4%[14/33] and 46.9% [15/32] with overcorrection vs. 10.7%[3/28] and 13.3% [4/30] with undercorrection for angle
and height, respectively; p<0.01).
Conclusions: Overcorrection of fractured vertebrae may
associate with the increased incidence of adjacent fractures when BKP is performed.

PS-FP-10-6

Pros and Cons of Full Endoscopic Surgery for
Cervical Radiculopathy
Kuniyoshi Tsuchiya
Department of Orthopaedic Surgery, JCHO Kyushu Hospital, Fukuoka,
Japan

Purpose: Although posterior surgery for cervical radiculopathy has been widely used, there is scarce amount ofknowledge about pros and cons of surgery with endoscope with rigid working channel. Results of posterior
surgery for cervical radiculopathy using full endoscopic
discectomy (FED) were retrospectively reviewed. Technical issues and pitfalls of this surgery were also discussed.
Methods: Seven patients that underwent posterior decompression surgery using FED systems have completed
12-month follow-up. All of the patients were sufferedfrom radiculopathy due to cervical disc herniation.
Results: Mean surgical time was 97 minutes and bleeding
were minimum in all cases. There were no intraoperative
incidents. Average radiculopathy score of the patients
before surgery was 10.8, which was improved to 17.5 at

S135

3 months and was 18.0 at 1 year. Surgery using FED devices, which have working port inside has substantial benefit to reduce soft tissue damage owing to their reduced
size compared to other optic devices. On the other hand,
surgical instruments that can be used with the devices
have limitation in their size because they have to be able
to pass through working port, and also have limitationin their motion axis, that is reciprocal and rotatory manner. Maximal precaution is necessary for not being lostin orientation. Severe degenerative change makes it moredifficult to correctly locate neural tissue and surrounding
compression factors. Closer viewing point obtained bydeeper placement of scope to the neural structures makes
it possible not only to observe them more clearly, but also
give some possibility to reduce amount of bone resectionin order to viewing target tissue. This feature also makes
procedures safer and more comfortable when surgeons
once have got used to. To appreciate this advantage, precise orientation and strict bleeding control are mandatory.
Perfusion used in FED surgery makes it possible to release
vessels from other surrounding tissues by hydrostaticpressure, thus make it easier to control bleeding from epidural vessels. Debris and fat tissue floating in perfusion
liquid will be obstacles in the field and should be properly
managed.
Conclusions: Deep and closer eye point is a substantial
advantage in FED surgery. On the other hand, migrationof the scope into spinal canal should be carefully avoided
to prevent neurologic complications. Although the small
diameter of the devices give substantial benefit to FED
surgery, this feature can result in a higher possibility ofwrong level surgery and this risk should also be considered.

PS-FP-10-7

Functional Outcomes of Loupe Assisted
Discectomy in Patients with Lumber Disc
Herniation
Shehar Yar Abid, Muhammad Tahir Karim, Shahid Ali
Orthopaedic Surgery Unit-1, Jinnah Hospital, Lahore, Pakistan

Purpose: To evaluate the efficacy of loupe-assisted discectomy in patients with lumbar disc herniation.
Methods: It is a retrospective observational study. A sample

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Asian Spine J 2021;15(Supplement 1):S1-S177

of 61 consecutive patients was taken who were operated
in a major tertiary care hospital of Lahore. The study took
data from patients of herniated lumbar disc who were
between the ages of 18–80 years and were operated by thesame surgeon over the period of 1 year. Patients with spinal canal stenosis, previous history of lumbar disc surgery
and patients with multilevel disc herniation were excluded
from the study. A purpose-built questionnaire was used torecord demographic and clinical data. Preoperative painscore by the pain Visual Analog Scale (VAS) and functional outcomes by the MMC were assessed upon enrollment
in the study. The postoperative pain score by the pain VAS
and functional outcomes by the MMC were assessed at
6-month follow-up. Data was entered and analyzed by using IBM SPSS ver. 22.0 (IBM Corp., Armonk, NY, USA).
Results: A total of 39 out of 61 patients were females while
22 were males. L4–L5 was the most common level of surgery and 42 (68.8%) patients had surgery of this level. The
number of patients having surgeries of L3–L4, L2–L3, andL1–L2 were 11 (18%), 6 (9.8%), and 2 (3.2%), respectively.
A total of 58 patients (95%) reported no pain or restriction of mobility at 6-month follow-up and hence, fell in“excellent” category of the MMC. Only 3 (5%) patients
reported occasional non-radicular pain and fell in “good”
category of the MMC. None of the subjects were stillhandicapped or reported continued objective symptomsof root involvement after the surgery.
Conclusions: The long-term results of loupe assisted lumbar discectomy are substantial and almost all the patientsin the study got back to their normal routine of physicalactivities. So, Loupe assisted discectomy is safe and comparable with endoscopic discectomy and other minimallyinvasive modalities of discectomy.

PS-FP-10-8

Indirect Neural Decompression by Transforaminal
Lumbar Interbody Fusion Using Minimally
Invasive Spine Surgery for Lumbar Degenerative
Spondylolisthesis: Comparison with Lateral
Lumbar Interbody Fusion
Ichiro Torigoe1, Yoshiyasu Arai1, Kenichiro Sakai1,
Masaki Tomori1, Kyohei Sakaki1, Takuya Oyaizu1,
Keigo Hirai1, Atsushi Okawa2
1

Department of Orthopaedic Surgery, Saiseikai Kawaguchi General Hospital,
Kawaguchi, Japan2
Department of Orthopaedic Surgery, Tokyo Medical and Dental University,
Tokyo, Japan

Purpose: To compare indirect neural decompression(IDD) effect by transforaminal lumbar interbody fusion
using minimally invasive spine surgery (MIS-TLIF) withthat by lateral lumbar interbody fusion (LLIF) for lumbar
degenerative spondylolisthesis (LDS).
Methods: Thirty-three patients with LDS at L4/5 level(mean age, 64.1 years) who underwent MIS-TLIF (15 patients) or LLIF (18 patients) were included in this study.
We analyzed operation time (OT), intraoperative blood
loss (BL), changes in local intervertebral angle (IVA), slip
rate (SR), intervertebral disc height (DH), and changes inthe L4/5 canal area on magnetic resonance imaging scans(between preoperative and 1 week postoperatively).
Results: The mean OT/BL in the two procedures wereequivalent (MIS-TLIF: 150 minutes/47 g, LLIF: 160 minutes/32 g). Regarding the IVA, SR, and DH, there was no
significant difference between two procedures; similarly,
the L4/5 canal area were also equivalent (MIS-TLIF: 51.5
to 96.3 mm2, LLIF: 65.2 to 94.3 mm2).
Discussion: There have been many reports showing good
IDD by LLIF. However, in consideration of the potential
risk of critical organ damage, the LLIF should be adopted
with care especially for the L4/5 level lesions. Our MISTLIF can be also have good IDD effect, and therefore, thisprocedure should be considered as an option for treating
LDS.

Asian Spine Journal
PS-FP-10-9Transforaminal Full-Endoscopic Discectomy
for the Patients with Down-Migrated Lumbar
Disc Herniation under Local Anesthesia
Fumitake Tezuka1, Kazuya Kishima1,2, Kiyoshi Yagi1,3,
Kosuke Sugiura1, Masatoshi Morimoto1,
Kazuta Yamashita1, Koichi Sairyo1
1

Department of Orthopedics, Tokushima University, Tokushima, Japan
Department of Orthopaedic Surgery, Hyogo College of Medicine,
Nishinomiya, Japan3
Department of Orthopaedic Surgery, Nagoya City University Medical
School, Nagoya, Japan
2

Purpose: The application of transforaminal full-endoscopic discectomy (TELD) for down-migrated lumbar discherniation (DM-LDH) is difficult because of interferencewith surrounding anatomical bony structures. Therefore,
in general, interlaminar full-endoscopic discectomy isconducted.
Methods: Between January 2014 and March 2020, among
203 patients who underwent TELD in our institution, 169
patients who have excluded the cases of recurred LDH,
lateral-type LDH, and multiply operated back were included in this study. All patients underwent TELD under local
anesthesia. The definition of DM-LDH was that the top of
LDH was below the cranial endplate line of the caudal vertebra (E line) on the sagittal magnetic resonance imaging(MRI) T2 weighted image. We retrospectively evaluatedpreoperative/postoperative MRIs and clinical results. The
distance of the tip of DM-LDH below the E-line was measured on preoperative MRIs, and removal of DM-LDH waschecked on postoperative MRIs. Clinical results on followup visits were evaluated by MacNab’s criteria.
Results: Twenty-nine patients (21 males, eight females)
had DM-LDH, and their mean age was 39.2 years old.
Preoperative MRI showed that the average distance of
DM-LDH was 8.1 mm (range, 4.2 to 15.0 mm). On thelateral view of the lumbar radiograph, tips of DM-LDH
in six patients were far from the midline of pedicle line
(highly DM-LDH). Postoperative MRI revealed that 10
patients achieved complete removal of DM-LDH, 17 cases
did the partial reduction of DM-LDH, and two patientsremained DM-LDH. Among 29 patients, 16 patients wereexcellent, 11 patients were good, and two patients werefair on MacNab’s criteria.
Conclusion: Present study revealed satisfactory clinical

S137

results on MacNab’s criteria for the patients who had DMLDH and underwent TELD under local anesthesia. There
were two patients who were not achieved satisfactory
results in TELD. One remained DM-LDH on postoperative MRI, and the other had highly DM-LDH. However,among six patients who had highly DM-LDH, four patients achieved excellent clinical results. Foraminoplasty
is the procedure of widening the intervertebral foramen
using a high-speed drill which removes the ventral sideof the supra-articular process and the cranial side of thepedicle. TELD with foraminoplasty could visualize thelateral part of DM-LDH and help easier resection.

PS-FP-10-10

Transforaminal Full-Endoscopic Ventral
Facetectomy: Mid-Term Results and Factors
Associated with Fair/Poor Outcome
Kazuya Kishima1,2, Kiyoshi Yagi2,3, Keishi Maruo1,
Toshiya Tachibana1, Masatoshi Morimoto2,
Fumitake Tezuka2, Kazuta Yamashita2, Toshinori Sakai2,
Toru Maeda2, Koichi Sairyo2
1

Department of Orthopaedic Surgery, Hyogo College of Medicine,
Nishinomiya, Japan2
Department of Orthopedic Surgery, Tokushima university, Tokushima, Japan3
Department of Orthopedic Surgery, Nagoya City University, Nagoya, Japan

Purpose: The aim of this study was to examine the postoperative results of transforaminal full-endoscopic ventral
facetectomy (TF-FEVF) for lateral recess stenosis (LRS)
and to elucidate the factors associated with poor surgicaloutcome.
Methods: This study involved 85 patients (47 males) who
underwent FEVF for LRS. Mean age was 70.5 years andmean follow-up duration was 14.8 months. Data werecollected on sex, age, surgical level, diagnosis, history ofspinal surgery at the same level, and duration of followup. Diagnosis was categorized as lumbar spinal stenosis
with or without disc bulging. Clinical evaluation was
performed using the modified MacNab criteria. Magnetic
resonance imaging was used to evaluate the degree of discdegeneration, vertebral endplate degeneration, disc height,
thickening of the ligamentum flavum, and stenosis. Bonystenosis was evaluated using computed tomography. Using the modified MacNab criteria, we compared all variables between patients with excellent/good outcome (E/G

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Asian Spine J 2021;15(Supplement 1):S1-S177

group) and those with fair/poor outcome (F/P group).
Results: According to the modified MacNab score, theoutcome at the final follow-up was excellent in 39 cases,
good in 21, fair in 13, and poor in 12. There was no significant difference in sex, age, diagnosis, history of spinal
surgery, or duration of follow-up between the 60 cases(70.6%) in the E/G group and the 25 in the F/P group(29.4%). Imaging evaluation revealed statistically significant differences in sagittal angulation (4.3° vs. 8.1°,
p<0.05), sagittal translation (0.7 mm vs 1.6 mm, p<0.05),
and Cobb angle (−0.5° vs. −1.9°, p<0.05) between the E/Ggroup and the F/P group.
Conclusions: Mid-term results of FEVF surgery weregenerally favorable. Factors associated with fair/poor outcome of FEVF were large sagittal angulation, large sagittaltranslation, and concave side.

PS-FP-10-11

Unintentional Facet Fusion without Bone
Grafting after Minimally Invasive Lumbar
Interbody Fusion: A Retrospective Study of
Percutaneous Endoscopic Transforaminal
Lumbar Interbody Fusion
Katsuhisa Yamada1, Ken Nagahama2, Yuichiro Abe3,
Masahiko Takahata1, Norimasa Iwasaki1
1

Department of Orthopaedic Surgery, Hokkaido University, Sapporo, Japan
Sapporo Endoscopic Spine Surgery Clinic, Sapporo, Japan
3
Wajokai Eniwa Hospital, Eniwa, Japan
2

Purpose: We previously developed a percutaneous endoscopic transforaminal lumbar interbody fusion (PETLIF)
procedure. During postoperative follow-up, we encountered patients in whom bone fusion occurred between
opened facet joints, despite not having bone grafting in
the facet joints. In this study, we investigated the frequency and tendencies of facet fusion following PETLIF in
comparison with open transforaminal lumbar interbody
fusion (TLIF).
Methods: Subjects underwent either single-level PETLIF
or open TLIF at our hospital from April 2015 to March
2019. Patients were assessed with lumbar X-ray images
and computed tomography (CT) prior to surgery, immediately after surgery, and 1 year after surgery. Comparative
statistical analyses of each parameter of patient back-ground and image findings were conducted between the
PETLIF and TLIF groups.
Results: Forty-two patients with PETLIF and 27 patientswith open-TLIF were evaluated for facet fusion by CT at
1-year postoperatively. Facet fusion was observed in 26 of
42 post-PETLIF patients (61.9%). The average inter-facet
distance increased from 1.3 mm prior to surgery to 4.5mm after surgery, and facet fusion was observed under
the opened conditions of 3.8 mm at 1 year. There were no
significant differences in patient background, correction
loss of segmental lordosis, or inter-facet distance between
the facet fusion and facet non-fusion subgroups. Facet fusion was observed among three patients in the open TLIF
group (11.1%), which was significantly lower than in the
PETLIF group (p<0.01). There were no significant differences in the rate of interbody bone bridge formation or
correction loss of segmental lordosis between the PETLIF
and open TLIF group (p=0.28, p=0.07, respectively).
Conclusions: Bone ingrowth and facet fusion was achieved
over time within the facet joints that were opened throughindirect decompression after PETLIF. To address themechanism for facet fusion without bone grafting, we hypothesized that the preserved facet joints potentially became the base bed for spontaneous bone fusion due to thepreserved facet joint capsule and surrounding soft tissue,
which maintained cranio-caudal facet traffic and blood
circulation in the facet joints. The complete preservationof the facet joints was considered a key advantage of minimally invasive lumbar interbody fusion procedures.

PS-FP-10-12

The Advantages of Revisional Transforaminal
Full-Endoscopic Spine Surgery for Patients
Underwent Posterior Spine Surgery
Kiyoshi Yagi1,2, Kosuke Sugiura2, Makoto Takeuchi2,
Kazuya Kishima1,3, Masatoshi Morimoto2,
Fumitake Tezuka2, Kazuta Yamashita2, Yoichiro Takata2,
Toshinori Sakai2, Toru Maeda2, Koichi Sairyo2
1

Department of Orthopaedic Surgery, Graduate School of Medical Sciences,
Nagoya City University, Nagoya, Japan2
Department of Orthopedics, Tokushima University, Tokushima, Japan3
Department of Orthopedic Surgery, Hyogo College of Medicine,
Nishinomiya, Japan

Purpose: Revisional lumbar spinal surgery by posterior

Asian Spine Journal
approach is more challenging than primary surgery due to
epidural or perineural scar tissue. It demands to further removal of posterior structure to confirm intact boney landmarks and could cause operation-related instability, so fusion surgery was often selected. However, adjacent segment
disease after fusion surgery could be a problem and further
exposure of posterior muscles could cause multiple operated back syndrome. To resolve these problems, we have
performed transforaminal full-endoscopic spine surgery(TF-FES) for patients underwent posterior lumbar surgery.
The purpose of this study is to evaluate clinical outcomesof revisional TF-FES and describe the advantages.
Methods: Forty-eight consecutive patients (60 levels) underwent revisional TF-FES for under local anesthesia. Revisional surgery was defined as the surgery after ipsilateralpartial laminectomy in the same intervertebral level and/or lumbar fusion surgery in the adjacent level. Intraoperative blood loss, operation time, and the rate of complication were evaluated. Postoperative clinical outcomes wereassessed by modified Macnab criteria outcome and Visual
Analog Scale (VAS) for leg pain, back pain, and leg numbness. In addition, we compared the outcome of revisional
FES cases and primary FES cases matched for age, sex,level, and procedure of FES.
Results: The mean operation time was 70.5±14.4 minutes(range, 52–106 minutes), and blood loss was unmeasurable. The clinical outcomes were rated as follows: excellent in 16 levels (26.7%), good in 28 levels (46.7%), fairin 10 levels (16.7%), poor in 6 levels (10.0%). The mean
preoperative VAS for back pain was 6.0±2.6, for leg pain
was 6.8±2.4, and for leg numbness was 6.3±2.8. At thelast follow-up, the mean postoperative VAS for back pain
was 4.3±2.5, for leg pain was 3.8±2.6, and for leg numbness was 4.6±3.2. VAS score was significantly improved(p<0.05). In addition, no significant difference was observed in the operation time, blood loss, and complication
rate between revisional FES and primary FES.
Conclusions: Clinical outcomes of revisional TF-FES for
patients with a history of posterior lumbar spine surgery
was good. We consider the advantages of revisional TFFES are avoiding effect of adhesion due to another routeand preserving posterior structures. It could provide only
decompression without fusion due to avoiding operationrelated instability. In addition, it can be performed in an
awake and aware state under local anesthesia and direct
decompression for foraminal and lateral recces stenosis
can be done. TF-FES could be an effective procedure for

S139

patients underwent posterior lumbar spine.

PS-FP-10-13

Risk Assessment of Abdominal and Retroperitoneal
Organ Injuries Performing Transforaminal
Full-Endoscopic Spine Surgery
Kiyoshi Yagi1,2, Kosuke Sugiura2, Makoto Takeuchi2,
Kazuya Kishima2,3, Masatoshi Morimoto2,
Fumitake Tezuka2, Kazuta Yamashita2, Yoichiro Takata2,
Toshinori Sakai2, Toru Maeda2, Koichi Sairyo2
1

Department of Orthopaedic Surgery, Graduate School of Medical Sciences,
Nagoya City University, Nagoya, Japan2
Department of Orthopedics, Tokushima University, Tokushima, Japan3
Department of Orthopedic Surgery, Hyogo College of Medicine,
Nishinomiya, Japan

Purpose: Transforaminal full-endoscopic spine surgery(TF-FES) is a minimally invasive procedure for the surgical treatment of lumbar hernia and degenerative disease
and has several advantages for the patients. Severe complications such as abdominal and retroperitoneal injuries
have never been reported. However, the biggest pitfall of
minimally invasive spine surgery is that we cannot visualize the anatomical structures during approaching theaffected surgical site. TF-FES has risks of abdominal andretroperitoneal organs injuries due to taking the insertion
point outside. The purpose of this study is to investigate
organs that could exist in the trajectory of TF-FES.
Methods: We evaluated whether organs (liver, ascending
and descending colon, kidney, spleen) and bones (rib, iliac
crest) appear in the trajectory of TF-FES using preoperative lumbar spine computed tomography image taken in
the prone position. Fifty cases (33 males and 17 females)
were evaluated at each L1/2–L5/S1 disc level. The mean age
was 52.0 years (range, 17–91 years). We assumed the medial interpedicular line as the cannula installation position.
The maximum tilt angle of the trajectory inserted without
interfering with organs (liver, ascending and descending
colon, kidney, spleen) and bones (rib, iliac crest) was measured.
Results: The organs/bones (number of cases; right/left)interfered with the trajectory when tilted up to 90 ° were
kidney (19/18), rib (21/20), spleen (-/1), and colon (0/1)
at L1/2. Similarly, kidney (11/14), rib (1/3), and colon(3/2) at L2/3, kidney (1/1) and colon (6/7) at L3/4, colon

S140

Asian Spine J 2021;15(Supplement 1):S1-S177(1/0) and iliac crest (23/20) at L4/5, and iliac crest (50/50)
at L5/ S1, respectively. When interfered with any bones/
organs, the mean±standard deviation tilt angle (right/left)
was 74.7°±8.6°/74.1°±9.6° at L1/2, 77.8°±9.0°/79.3°±7.7°
at L2/3, and 82.8°±7.0°/84.0°±4.2° at L3/4,
70.5°±9.5°/70.0°±7.7° at L4/5, and 50.1°±6.4°/50.4°±7.0° at
L5/S1, respectively.
Conclusions: Abdominal and retroperitoneal organs
could appear backward than the tangent line of the posterior edge of the disc in the upper lumbar intervertebral
disc level. It is risky to approach from far-lateral point
horizontally, in particular in the upper lumbar level. It is
important to assess the possible risk to avoid the severe
complication in FES.

PS-FP-10-14

Is Bipolar Release of Sternocleidomastoid
Muscle Necessary for Neglected CongenitalMuscular Torticollis?
Haruki Funao1,2,3, Kenshi Daimon1,2, Kento Yamanouchi2,
Tomoharu Tanaka3, Norihiro Isogai1,3, Yutaka Sasao1,3,
Shigeto Ebata1,2, Ken Ishii1,2,3
1

Department of Orthopaedic Surgery, School of Medicine, International
University of Health and Welfare, Otawara, Japan2
Department of Orthopaedic Surgery, International University of Health andWelfare Narita Hospital, Narita, Japan3
Department of Orthopaedic Surgery, International University of Health andWelfare Mita Hospital, Tokyo, Japan

Purpose: The majority of congenital muscular torticollis(CMT) resolves spontaneously or improves by non- surgical treatment during infancy. Although surgical releasesof the affected sternocleidomastoid muscle (SCM) are
required for resistant or neglected CMT, there has beenrarely reported in adolescent or adult patients. Here, we
assessed surgical outcomes of bipolar and unipolar releaseof SCM in adolescent or adult patients with neglected
CMT.
Methods: Eleven consecutive patients with neglected
CMT who underwent surgical release of the affected
SCM were enrolled. All patients complained of cosmetic
problems and restricted range of motion (ROM) of thecervical spine. Three patients were treated by bipolar release of SCM (B group), and eight patients were treatedby unipolar release of SCM (U group). All patients werereceived physical therapy and early mobilization after sur-gery. Clinical and radiographic outcomes were compared
between the two groups, and Student t-test was used forstatistical analysis.
Results: Mean age was 40 years in B group, and 24 years in
U group. There was no significant difference between thetwo groups. Operative time was significantly shorter in
U group (60 minutes) compared to B group (41 minutes)(p<0.01). There was no significant difference in blood loss
between the two groups. Cervicomandibular angle (CMA)
significantly improved from 11° to 3° in B group (p<0.01),
and from 15° to 3° in U group (p<0.01) after surgery. The
ratios of the difference between preoperative and postoperative angles per preoperative angle of CMA were 75%
in both groups, and there was no significant difference
between the two groups. C2 sagittal vertical axis improved
from 29 to 15 mm in B group (p=0.20), and that was significantly improved 33 to 21 mm in U group (p<0.05). All
patients improved cosmetic problems and cervical ROM.
Cheng and Tang’s scoring were 17 points in both groups,
and there was no significant difference between the twogroups. There were no major complications, although one
transient neurological deficit of greater auricular nerve
was observed in B group.
Conclusions: We found no significant differences of surgical outcomes between bipolar and unipolar release of
SCM even in adolescent or adult patients with neglected
CMT. Unipolar release of SCM and early mobilization
would be a less invasive procedure, reducing surgical scar,a risk of greater auricular nerve damage, and operative
time.

PS-FP-10-15

Usefulness and Problems of the Double
Endplates Penetrating Screw Technique forPatients with Diffuse Idiopathic Skeletal
Hyperostosis
Takumi Takeuchi1, Kenichiro Yamagishi2, Masaaki Tsuji1,
Hideto Sano1, Masato Takahashi1, Shoichi Ichimura1,
Hitoshi Kouno3, Naobumi Hosogane1
1

Department of Orthopedic Surgery, Kyorin University, Tokyo, Japan
Department of Orthopedic Surgery, Higashiyamato Hospital, Tokyo, Japan3
Department of Orthopedic Surgery, Keiyu Orthopedic Hospital,
Tatebayashi, Japan
2

Purpose: We have developed the single or double end-

Asian Spine Journal
plates penetrating screw (SEPS/DEPS) technique which
is a novel percutaneous pedicle screw (PPS) insertion
technique suitable for vertebral body fracture patientswith diffuse idiopathic skeletal hyperostosis (DISH). The
purpose of this study is to compare the effectiveness of
this SEPS/DEPS technique with the conventional pedicle
screw technique.
Methods: The screw is inserted upwards from the outercaudal side of the pedicle toward the inner cranial side.
Vertebrae affected with DISH were inserted with screws
using the SEPS/DEPS technique, whereas non-fused vertebrae were inserted with screws using the conventional
PPS technique. Twenty patients were treated with SEPS/
DEPS: 12 with osteoporotic vertebral body fracture, threewith pyogenic spondylitis, and one with metastatic spinal tumor. Seven patients were treated with SEPS/DEPS
technique only (D group) and 13 patients with a hybrid of
both the SEPS/DEPS and the conventional PPS technique(H group). We compared the rates of implant failures
and the revision surgery between the D group and the Hgroup.
Results: In the D group, 72 screws were inserted using theSEPS/DEPS techniques. In the H group, 98 screws wereinserted with the SEPS/DEPS technique and 78 screws
were inserted with the conventional PPS technique. There
was no implant failure in the D group; however, in the
H group, loosening was observed in 10 out of 78 screws(12.8%) by the conventional PPS technique, in two outof 98 screws (2%) by the SEPS/DEPS technique, with asignificant difference (p=0.005). In the D group, PLIF was
performed in a patient due to adjacent segment disorder
after bone fusion. In the H group, balloon kyphoplasty
was performed in three patients due to the adjacent vertebral body fracture in four patients.
Conclusion: This novel SEPS/DEPS technique is a useful
method for preventing implant failures due to its strong
fixation of the fused vertebra by DISH; however, longterm follow-up is necessary because failure tends to occur
at the distal end of fixation even after bone fusion.

S141

PS-FP-10-18

Percutaneous Transforaminal Endoscopic
Surgery and Oblique Lateral Interbody Fusion
with Self-Lock Cage for Surgical Treatment of
L5 Spondylolisthesis
Yutong Gu1,2
1

Department of Orthopaedic Surgery, Zhongshan Hospital Fudan University,
Shanghai, China
2
Department of Orthopaedic Surgery, Shanghai Public Health ClinicalCenter, Fudan University, Shanghai, China

Purpose: We designed percutaneous transforaminal endoscopic surgery (PTES) under local anesthesia and obliquelateral interbody fusion (OLIF) with self-lock cage throughabdominal lateral retroperitoneal approach in a rightoblique position for the treatment of L5 spondylolisthesis
in order to obtain the direct neurologic decompression,
rigid fixation and high fusion rate, and protect the rectus
abdominis and its sheath, paraspinal muscles, and bone
structures as much as possible. The purpose of study is toevaluate the feasibility, efficacy, and safety of this surgicalmethod.
Methods: Twelve cases of L5 spondylolisthesis with nerve
root symptoms were included in this study. PTES was
performed under local anesthesia in a prone position,and then the patients underwent OLIF with self-lock cage
through abdominal lateral retroperitoneal approach withthe external oblique, internal oblique and transverse abdominal muscles bluntly separated in turn for L5/S1 in aright oblique position under general anesthesia. Back andleg pain were preoperatively and postoperatively evaluated using Visual Analog Scale (VAS). And the clinicaloutcomes were evaluated with Oswestry Disability Index(ODI) at the 1-year follow-up. The fusion status was assessed according to the Bridwell’s posterior fusion grades.
Results: The mean duration of operation was 47.6±6.8
minutes per level for PTES and 79.4±11.7 minutes for
OLIF. The mean frequency of intraoperative fluoroscopy
was 5 times (range, 4–10 times) per level for PTES and6 times (range, 5–9 times) for OLIF. There was a mean
blood loss of 20 mL (range, 15–50 mL). The mean stay at
the hospital was 4 days (range, 3–5 days). The average follow-up duration was 19 months (range, 12–24 months).
For the clinical evaluation, the VAS pain index and the
ODI showed excellent outcomes. Fusion grades basedon the Bridwell grading system at 1-year follow-up were

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Asian Spine J 2021;15(Supplement 1):S1-S177

grade I in eight segments (66.7%), grade II in four segments (33.3%). No patients had any form of permanent
iatrogenic nerve damage and a major complication. No
failure of instruments was observed.
Conclusions: PTES and OLIF with self-lock cage is a good
choice of minimally invasive surgery for L5 spondylolisthesis, which can get direct neurologic decompression,easy reduction, rigid fixation, and solid fusion, and hardly
destroy the rectus abdominis and its sheath, paraspinal
muscles, and bone structures. OLIF for L5/S1 in a rightoblique position could let abdominal contents move tocontralateral side with gravity, which makes exposure ofsurgical vision easier.

PS-FP-10-20

Full Endoscopic Posterior Cervical Foraminotomy
under Lateral Decubitus Position with Local
Anesthesia
Do Hyeong Lim1, Michael Levitt1, Dong Wha Heo2,
Byeong Cheol Rim3
1

Stroke and Applied NeuroScience Center, Department of Neurological
Surgery, University of Washington, Seattle, WA, USA
2
Department of Neurological Surgery, Seoul Bumin Hospital, Seoul, Korea
3
Department of Neurological Surgery, Madisarang Hospital, Cheongju,
Korea

Purpose: Almost half of the worldwide population is expected to experience clinically significant neck pain, andsome severe cases require surgical interventions. Here we
introduce a novel minimally invasive endoscopic technique as an alternative way for simple decompression forpatients with foraminal stenosis and contraindications togeneral anesthesia, allowing for minimal muscle dissection, shortened surgical time, and reduced complications.
Methods: Patients with cervical foraminal stenosis withsevere pain and medical comorbidities that increase therisk of general anesthetic were included in the study. First,
the patient is placed in the lateral decubitus position withthe asymptomatic side down and the neck parallel to thetable. The posterior neck is draped, and subcutaneousbupivacaine 0.25% is injected for local anesthetic. Thenworking portal is placed on the facet joint aiming medial
pedicle line with fluoroscopic guidance, approaching the
midline to obliques posteroanterior on the side and at
the level of the patient’s pain. With the maximum fluoro-

scopic magnification, the neural foramen is placed at thecenter of the fluoroscopic field of view and kept in placethroughout the surgery. An endoscopic port is placed overthe needle tract, and decompression is performed by removing the inferior facet of the upper lamina and partial
removal of the inferior lamina’s superior facet. Adequate
foraminal decompression is obtained through bony removal until the dura mater’s lateral border is visualized.
Results: Nine patients (eight males, one females; meanage, 50 years), who have complaints of pain but refused
general anesthesia or patients with a difficult airway, weretreated with an average operation time of 55 minutes. All
nine cases had significant improvement in cervical radicular pain via the Visual Analog Scale (VAS). The median
improvement of VAS was 7, and there were no perioperative complications.
Conclusions: Awake endoscopic cervical foraminal
decompression is a feasible alternative to standard approaches for patients with a difficult airway or underlying
pulmonary diseases, reducing the risks inherent in generalanesthesia and cranial fixation.

PS-FP-10-21

Three-Year Clinical Outcomes after Minimally
Invasive Sacroiliac Joint Arthrodesis Using
Triangular Implants in Japan: A Pilot Study ofFive Cases
Daisuke Kurosawa1, Eiichi Murakami1, Hiroaki Koga2,
Hiroshi Ozawa3
1

Department of Orthopaedic Surgery, Low Back Pain and Sacroiliac Joint
Center, JCHO Sendai Hospital, Sendai, Japan2
Department of Orthopaedic Surgery, Kyushu Low Back Pain and Sacroiliac
Joint Center, Nanpu Hospital, Kagoshima, Japan3
Department of Orthopaedic Surgery, Tohoku Medical and Pharmaceutical
University School of Medicine, Sendai, Japan

Purpose: Sacroiliac joint (SIJ) arthrodesis using a minimally invasive technique, particularly the triangularimplant system, is performed in patients with SIJ dysfunction in the United States and Europe. We report the threeyear clinical outcomes of the first minimally invasive SIJ
arthrodesis procedures using the implants performed inJapan.
Methods: A total of five patients (one man and four
women; age, 56.4±16.9 years) with SIJ pain who under-Asian Spine Journal
went SIJ arthrodesis using a triangular implant system in2017 were included. In addition to operation time andblood loss, pain intensity (Visual Analog Scale [VAS]) andfunctional impairment (Oswestry Disability Index [ODI])
were assessed preoperatively and at 36-month follow-up.
Computed tomography image-based evaluation of implant loosening and satisfaction with the surgery was also
evaluated at 12 and 36 months.
Results: The surgical time was 67.7±13.1 minutes andblood loss was 7.4±6.9 mL. The mean VAS value improved significantly from 88.0±8.4 to 33.6±31.9 mm at
3 months and was maintained at 46.4±30.9 mm at 36
months (p<0.05). The mean ODI improved significantly
from 76.4%±3.8% to 46.2%±21.9% at 6 months postoperatively (p<0.05), but without significant improvements
thereafter: 46.94%±23.7% (12 months) and 66.4%±8.6%(36 months). Three of five patients showed at least one
implant loosening on the sacrum side. A total of 80% (4/5)
of patients reported satisfaction with the surgery at 12
months and 60% (3/5) at 36 months.
Conclusions: Using a triangular implant system yieldedsomewhat poorer results in our study than in previous
provider-supported studies; however, this technique wasa valuable option to minimize invasiveness in SIJ surgery.
Patients should be carefully selected and the degree ofbony fragility of the sacrum in elderly patients should beconsidered.

PS-FP-10-24

Does Prophylactic Use of Topical GelatinThrombin Matrix Sealant Affect Postoperative
Drainage Volume and Hematoma Formation
after Microendoscopic Spine Surgery?: A
Randomized Controlled Trial
Masanari Takami, Hiroshi Hashizume, Yasutsugu Yukawa,
Hiroshi Iwasaki, Shunji Tsutsui, Keiji Nagata, Ryo Taiji,
Shizumasa Murata, Takuhei Kozaki, Hiroshi Yamada
Department of Orthopaedic Surgery, Wakayama Medical University,
Wakayama, Japan

Purpose: There has been no data on whether postoperative
epidural hematoma (PEH) is suppressed by these agents
when administered in microendoscopic spine surgery.
The objective of this study was to investigate the effectS143

of topical gelatin-thrombin matrix sealant (TGTMS) on
bleeding and PEH formation in lumbar microendoscopic
surgery.
Methods: This is a randomized controlled trial (RCT)with additional prospective observational cohort. Patientswere registered from July 2017 to September 2018 and
103 patients undergoing microendoscopic laminectomy
for lumbar spinal stenosis at a single institution were enrolled. The primary outcome was the drainage volume
within 48 hours after surgery. Secondary outcomes were
the Numerical Rating Scale (NRS) of leg pain on the second (NRS2) and seventh day (NRS7) after surgery and thehematoma area ratio (HAR) in horizontal images on magnetic resonance imaging (MRI). In the RCT, 41 cases thatreceived TGTMS (F group) were compared with 41 control group cases (C group) that did not receive TGTMS at
the end of the procedure. Drainage volume, NRS2, NRS7,
and HAR on MRI were evaluated. Nineteen cases were excluded from the RCT (I group) due to difficulty of hemostasis during surgery and the intentional use of TGTMS
for hemostasis. I group was compared with C group in thedrainage volume and NRS of leg pain as a prospective observational study.
Results: The RCT demonstrated no statistically significant
difference in drainage volume between those receiving
TGTMS (117.0±71.7; mean±standard deviation) andcontrols (125.0±127.0) (p=0.345). The NRS2 and NRS7
was 3.5±2.6 and 2.8±2.5 in the F group, respectively, and
3.1±2.6 and 2.1±2.3 in the C group, respectively. The HAR
on MRI was 0.19±0.19 in the F group and 0.17±0.13 in
the C group. There was no significant difference in postoperative leg pain and HAR (p=0.644 for NRS2, p=0.129
for NRS7, and p=0.705 for HAR). In the secondary observational cohort, the drainage volume in the I groupwas 118.3±151.4, and NRS2 and NRS7 was 3.5±2.0 and
2.6±2.6, respectively. There were no statistically significant
differences in drainage volume (p=0.386) or postoperative
NRS of leg pain between these two groups (p=0.981 and
0.477 for NRS2 and NRS7, respectively).
Conclusions: The prophylactic use of TGTMS in patients
undergoing microendoscopic laminotomy for lumbar
spinal stenosis did not demonstrate any difference in postoperative bleeding or PEH. Nonetheless, for patients that
had active bleeding that required the use of TGTMS, there
was no evidence of difference in postoperative clinicaloutcomes relative to controls.

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PS-FP-10-26

Comparison Between Clinical Outcomes ofSimultaneous Parallel Anterior and Posterior
Combined Lumbar Spine Surgery Using
Intraoperative Three-Dimensional FluoroscopyBased Navigation (SPAPS) and Minimally
Invasive Posterior/Transforaminal Lumbar
Interbody Fusion
Tomohiko Hirose, Hisanori Ikuma
Department of Orthopaedic Surgery, Kagawa Prefectural Central Hospital,
Takamatsu, Japan

Purpose: Minimally invasive posterior/transforaminal
lumbar interbody fusion (MI-PLIF/TLIF) is a surgery
commonly performed for lumbar interbody fusion. Since
2016, we have been performing a new surgery named simultaneous parallel anterior and posterior combined lumbar spine surgery under intraoperative three-dimensional
fluoroscopy-based navigation (SPAPS) for degenerative
lumbar disease. This study aims to compare the clinicaloutcomes of SPAPS and MI-PLIF/TLIF.
Methods: We retrospectively reviewed data from 56 patients who underwent SPAPS or MI-PLIF/TLIF for singlelevel degenerative lumbar disease in our hospital between
April 2016 and December 2019. Twenty-five patients underwent SPAPS (group S), and 31 patients underwent MIPLIF/TLIF (group PT). The patients were followed up for≥6 months. The mean age was 63.7 years in group S and69.5 years in group PT. The following items were evaluated: operative time, estimated blood loss (EBL), perioperative complications, Japanese Orthopaedic Association
Back Pain Evaluation Questionnaire (JOABPEQ), andVisual Analog Scale (VAS) scores, preoperatively and at 6
months postoperatively.
Results: The surgical time and EBL were significantly better in group S (119.1 minutes and 82.5 mL, respectively)
than those in group PT (167.0 minutes and 160.1 mL,
respectively) (p<0.01). One patient in group PT showed
an epidural hematoma postoperatively and required reoperation. The postoperative scores of JOABPEQ and VAS
significantly improved in both groups, and no significant
differences were observed between the groups.
Conclusions: SPAPS was associated with a shorter operative time and lesser EBL than MI-PLIF/TLIF. Further,
SPAPS may contribute to lower medical costs because of

the reduced operative time and material costs.

PS-FP-10-27

Evaluation of Cement Leakage Using Computed
Tomography after Balloon Kyphoplasty:
Comparison between Patients Underwent
within 4 Weeks and Patients Underwent after 4
Weeks
Hiroyuki Yasuda1, Sadahiko Konishi1, Masaki Terakawa1,
Hiroaki Nakamura2
1

Department of Orthopedic Surgery, Osaka General Hospital of West Japan
Railway Company, Osaka, Japan2
Department of Orthopedic Surgery, Osaka City University Graduate Schoolof Medicine, Osaka, Japan

Purpose: To evaluate prevalence of cement leakage using
computed tomography after balloon kyphoplasty (BKP)
for osteoporotic vertebral fracture (OVF). To compare
prevalence of cement leakage and factors affect cement
leakage between patients underwent within 4 weeks after
injury and patients underwent after 4 weeks.
Methods: In this study, 115 patients (male: 39 patients,
female: 76 patients; mean age, 80.2±6.8 years) underwent
BKP for OVF were enrolled. The patients were divided
into two groups according to time to BKP after injury.
Group A (n=60) consists of patients underwent within 4
weeks and group B (n=55) consists of patients underwent
after 4 weeks. Within a few days after BKP, cement leakage
was evaluated using computed tomography. Prevalenceof cement leakage was compared between two groups.
According to presence of cement leakage, each group was
divided into two subgroups (group A leakage+, group A
leakage-, group B leakage+, group B leakage-). In eachgroup, age, sex, cleft vertebral, range of motion (ROM)of vertebral body, amount of cement, and maximum diastolic pressure were compared.
Results: Prevalence of cement leakage was higher in group
A (p=0.001). Maximum diastolic pressure was higher ingroup A leakage+ (p=0.03). Prevalence of cleft, ROM ofvertebral body, and maximum diastolic pressure werehigher and amount of cement leakage was less in group
B leakage+ (p=0.008, p<0.001, p=0.02, p=0.001, respectively). There was no major perioperative complication.
Conclusions: Prevalence of cement leakage after BKP for
OVF was higher in patients underwent within 4 weeks

Asian Spine Journal

S145

after injury compared with patients underwent after 4
weeks. Factors affect cement leakage were different according to time of BKP after injury.

thors suggest that the UBE, which is a minimally invasive
procedure, is an alternative treatment option for thoracic
OLF.

PS-FP-10-28

PS-FP-10-29

Decompression Procedure Using Unilateral
Biportal Endoscopy for Thoracic Myelopathy
Caused by Ossification of the Ligamentum
Flavum: A Technical Note and Preliminary
Clinical Results

Treatment Results of Minimally Invasive
Lateral Lumbar Disc Herniated Disk in Our
Department

Seung-Hyun Choi1, Sang-Kyu Son2, Weon-Wook Park1

Yoshikazu Yanagisawa, Masayoshi Ohga
Spinal Disease Center, Department of Orthopedic Surgery, Fukuoka Mirai
Hospital, Fukuoka, Japan1

Department of Orthopedic Surgery, Park Weon Wook Hospital, Busan,
Korea
2
Department of Neurosurgery, Park Weon Wook Hospital, Busan, Korea

Purpose: The use of conventional spinal decompression
surgery for thoracic ossification of ligament flavum (OLF)
can be limited by technical difficulties and a restricted
field of vision. The purpose of this study is to describe thetechnique for decompression procedure using unilateral
biportal endoscopy (UBE) for thoracic OLF and analysisof clinical postoperative results.
Methods: The authors performed a unilateral laminotomy
with bilateral decompression using a unilateral biportal
endoscopy in patients with thoracic OLF. The authors
enrolled only patients who underwent follow- up for longer than 12 months after UBE. Fifty-eight patients wereenrolled in this study. This approach was based on two
portals: one portal was used for continuous input and endoscopic viewing and the other portal was used for continuous output and manipulating the instruments used in
the decompression procedures.
Results: Neural decompression was effectively performed
in all enrolled patients. The male-to-female ratio was 3:1.
Involvement of the upper thoracic region was seen 11
times; of the middle region 8 times, and of the lower region 40 times (several patients had involvement in morethan one region). About half of the patients complainedof gait disturbance on admission caused by the markedly
enlarged OLF. A dural tear in one patient was the only observed complication.
Conclusions: From a surgical point of view, UBE is very
similar to microscopic spinal surgery, permitting good visualization of the contralateral sublaminar areas. The au-

Purpose: Good treatment with various surgical methods
such as open surgery with Wiltse approach, endoscopic
surgery, and fusion surgery as a surgical method for lateral lumbar disc herniated disk (lateral LDH) including
the intervertebral foramen and extravertebral foramen.
Results have been reported. We report on the results ofsurgery using a microscope and a cylindrical retractor in
our department.
Methods: Since April 2018, 14 patients (male:female ratio=11:7; average age, 67.4 years) who have undergone
surgical treatment for lateral LDH in our department were
included. As a surgical method, the patient was placedin the abdominal position under inhalation anesthesia,
a vertical incision was added 2 cm, and a hernia was removed under a surgical microscope (Leica, M720 OH5)
using a cylindrical retractor (METRx, Medtronic). NIMECLIPSE E4 SYSTEM (Medtronic) was used for postoperative monitoring, triggered electromyogram (tEMG)
was recorded using a bipolar stimulation electrode whennerve root identification was difficult, and Floseal (Baxter)
was used for peri-nerve bleeding. The evaluation items
were high surgical level, presence or absence of tEMG
recording, postoperative complications, changes in localalignment as image evaluation before and after surgery,and Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ). The average operation
time is 121.8 minutes and the estimated bleeding volume
is 25.6 mL. The average follow-up period was 3.6 months(range, 1.2 to 34.8 months).
Results: The surgical levels were L2/3 (2 cases), L3/4 (5cases), L4/5 (6 cases), and L5/S (4 cases). The tEMG record was recordable in 11 of 13 cases, and no postopera-

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Asian Spine J 2021;15(Supplement 1):S1-S177

tive neurological complications were observed. Changes
in local scoliosis before and after surgery were observedin five cases with two or more exacerbations of scoliosis.
JOABPEQ pain improved significantly in the second year
(preoperative average 28.4 → postoperative 2 years 85.5),
and gait and society improved significantly in all 6 months
to 2 years after the operation, but the lumbar spine andpsychology No significant improvement was observed(non-repeated measures analysis of variance).
Considerations: Although this method showed deterioration of postoperative kyphoscoliosis in 35.7%, it is possible
to identify nerve roots by using intraoperative monitoring
together, and it is performed with minimal invasivenessby an operator who is proficient in open surgery without
fixation. It was considered that LDH was superior in that
it was relatively easy to introduce compared to endoscopic
surgery.

PS-FP-10-31

Effectiveness of Foraminoplasty in Transforaminal
Full-Endoscopic Discectomy for L5–S1 Disc
Herniation Under Local Anesthesia
Takashi Inokuchi, Kazuta Yamashita, Fumitake Tezuka,
Masatoshi Morimoto, Kazuya Kishima, Kiyoshi Yagi,
Koichi Sairyo
Department of Orthopedics, Tokushima University, Tokushima, Japan

Purpose: Full-endoscopic discectomy (FED) is a minimally invasive surgery for lumbar disc herniation (LDH).
Especially in transforaminal FED (TF-FED), surgeon can
perform FED under local anesthesia. However, it is difficult to approach for L5–S1 level in case of high-iliac andfacet hypertrophy. After our introduction of foraminoplasty, the drilling technique of superior articular process(SAP) using high-speed bur, we have performed TF-FED
for L5–S1 LDH. This study aimed to reveal the effectiveness of foraminoplasty in TF-FED.
Methods: We retrospectively reviewed 42 cases who had
undergone TF-FED for L5–S1 LDH in our hospital after
2014 (followed up at least 6 months). Hight of iliac in Xray (type 1–6: 1–4 low-, 5–6 high iliac), migration of LDH
in magnetic resonance imaging (zone 1–4: 1–2 up-, 3–4
down-migrate) and alpha angle in CT (angle between iliac
crest and SAP) were recorded. Macnab criteria was used

for clinical outcomes.
Results: Foraminoplasty was required in 22 cases (group1), and wasn’t required in 20 cases (group 2). No differences in migration between two groups. The ratio of highiliac was significantly higher in group 1 (group 1: 63%,
group 2: 50%). The average alpha angle was 52.1° in group
1 and 60.4° in group 2, respectively. In group 1, postoperative alpha average angle was 60.8°. According to Macnab
criteria, excellent 20, good 2 in group 1, excellent 10, good
9, poor 1 in group 2. No postoperative complication had
seen in both groups.
Conclusions: Foraminoplasty should be effective technique for L5–S1 LDH even in high iliac and down migration LDH.

PS-FP-10-32

Examination of Radiation Exposure in Lateral
Lumbar Fusion Surgery Using Intraoperative
Computed Tomography Navigation
Satoshi Nomura, Akihiko Hiyama, Kosuke Sako,
Masahiro Tanaka, Hiroyuki Kato, Daisuke Sakai,
Masato Sato, Masahiko Watanabe
Department of Orthopaedic Surgery, Tokai University School of Medicine,Tokyo, Japan

Purpose: In recent years, the reduction of radiation exposure by utilizing computer-assisted surgery with intraoperative computed tomography (CT) navigation has beenreported. However, reports on the actual patient exposure
dose are limited. At our institution, we are increasingly
using intraoperative CT navigation in lateral lumbar interbody fusion (LLIF) surgery to improve surgical precision compared to LLIF surgery using C-arm fluoroscopy.
This study investigates the intraoperative radiation dose in
LLIF surgery using intraoperative CT navigation for thepatient and surgeons.
Methods: From April to September 2020, radiation exposure was examined in 12 LLIF cases (eight males, four
females; average age, 72.4 years). Glass radiation dose meters were placed on the patient’s neck, left anterior chest,
and lower abdomen, and also on the outside and insidesurface of the chest area of the surgeon's radiation protective gear.
Results: The average fluoroscopy time was 125.6±70.9

Asian Spine Journal
seconds, and the average radiation dose was 2.0±1.6 mGy.
The radiation exposure of the patient according to area
is as follows: neck, 0.097±0.069 mGy; left anterior chest,
0.20±0.12 mGy, and lower abdomen 2.02±1.67 mGy. The
surgeon’s radiation dose was 0.029±0.024 mGy inside and0.119±0.111 mGy outside the protective clothing. Reported that the average radiation dose to LLIF patients using
the C-arm was 25.2±21 mGy. The radiation exposure inthis study using intraoperative CT navigation was lower
at 2.02 mGy, but we concede that these values cannot be
simply compared. In addition, Taher et al. reported exposure of 2.19±2.07 mGy for the surgeons with CT navigation.
Conclusions: Compared with radiation exposure in LLIF
surgery using C-arm which we reported in the past, there
was less radiation exposure, and we believe that intraoperative CT navigation not only improves surgical precision but decreases radiation exposure for both patientsand surgeons.

PS-FP-10-33

The Efficacy of Epiduroscopic Adhesiolysis on
Failed Back Surgery Syndrome
Osman Yağız Atlı, Burhan Kurtulus, Hakan Aslan

S147

stabilized. They all had persistent chronic back pain andradicular pain despite of medication and physical rehabilitation. Visual Analog Scale (VAS) for pain and Oswestry
Disability Index (ODI) were evaluated preoperatively,
after 1 month, 6 months and 1 year after the epiduroscopic adhesiolysis. The preoperative VAS was 7.4±70.234,
3.8±0.395 in the first postoperative month, 4.2±0.414
in the 6th month and 5.05±0.438 in the first year. The
preoperative ODI was 78.88±1.82, 54.43±3.32 in the first
postoperative month, 58.58±3.45 in the sixth month and62.16±3.42 in the first year.
Results: All patients, and also the subgroups (gender andstabilized/non-stabilized) improved significantly in pain(VAS) and disability (ODI) at all postoperatively visits.
There was no statistically significant difference between
the stabilized and non-stabilized groups in both preoperative scores and postoperative controls (p>0.05). However,the scores gradually returned to the preoperative value
thereafter. A slight worsening in VAS and ODI was noticed over time in both groups.
Conclusions: We suggest that epidural adhesiolysis, hasboth therapeutic and diagnostic effects, combined withhyaluronidase and steroid injection is an effective treatment for back and radicular pain in patients with FBSS.
Long-term randomized controlled studies are needed tobetter understand the efficacy of epiduroscopic adhesiolysis in FBSS.

Department of Orthopaedics and Traumatology, Saglik Bilimleri Unıversity
Dıiskapi SUAM, Istanbul, Turkey

Purpose: Symptoms of Failed Back Surgery Syndrome(FBSS) include low back pain, radicular pain, restricted
range of motion, muscle spasms, changes in motor andreflex function especially in lower limbs. Among themany treatment options of FBSS, successful results of epiduroscopic adhesiolysis, which is relatively less invasive,
have been previously reported. Epiduroscopy allows theadhesions to be removed mechanically by directly showing them, and at the same time, it allows the applicationof an anti-adhesion barrier (steroid, hyaluronidase, etc.)
to the epidural space. We aimed to compare the results oftreatment with mechanical lysis with epiduroscopy andsteroid hyaluronidase injection according to the stabilization status of patients with FBSS.
Methods: A total of 47 patients were included with a mean
age of 62,4 years (33–81), 28 women and 19 men. Amongthem, 20 were previously stabilized and 27 were non-

PS-FP-10-34

Retrospective Study of Clinical and Radiological
Outcomes of Minimally Invasive Transforaminal
Lumbar Interbody Fusion for High-Grade
Spondylolisthesis: Series of 24 Patients with
2-Year Follow-up
Rajendra Sakhrekar, Vishal Peshattiwar, Mohan Gawande
Department of Spine, Kokilaben Dhirubhai Ambani Hospital, Mumbai,
India

Purpose: High-grade spondylolisthesis has been variably
defined but the most accepted definition is to cases withmore than 50% displacement and listhesis with Meyerding grade three and higher. After the failure of appropriate nonoperative measures for controlling the symptoms,
postural deformity, slip progression, the operative meth-S148

Asian Spine J 2021;15(Supplement 1):S1-S177

ods are indicated. The surgical management of high-gradespondylolisthesis is a technically demanding. Many surgical methods have been reported have like posterior insitu fusion, instrumented posterior fusion with or without
reduction, combined anterior and posterior procedures,spondylectomy with reduction of L4 to the sacrum (forspondyloptosis), posterior interbody fusion with transsacral fixation. Although use of minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) spine
surgery for high-grade spondylolisthesis have not been
widely reported in literature.
Methods: A retrospective review of all patients with highgrade spondylolisthesis who were treated by the same surgeon at single institution was performed. The local institutional review board approved the study. Between 2017 and2019, there were 24 patients, who were surgically treatedfor high-grade spondylolisthesis of the lumbosacral junction associated with severe and persistent low back pain
and/or leg pain, or a neurologic deficit, after the failure ofnonoperative treatment. Preoperative pain (Visual Analog
Scale [VAS] score), functional ability (Oswestry Disability
Index [ODI], 36-item Short Form Health Survey [SF36]),
radiological parameters (slip angle, slip grade, foraminal
height, lumbar lordosis) were compared with postoperative recordings at the last follow-up. Operative time,
blood loss, and hospital stay were studied. Functional
improvement (SF36, ODI) and fusion (Bridwell fusion
criteria) were assessed. Statistical analysis with changes inparameters from preoperative to 2 years were analyzed.
The aim of this study is to show the clinical, surgical andradiographic results associated with the MIS TLIF for
high-grade spondylolisthesis in 24 patients.
Results: VAS score improved from 8 (7–9) to 0 (0–2) and
ODI improved from 39 to 4, also physical and mental
components of SF-36 showed improved. Radiologicalparameters slip angle, slip grade, disc height, foraminal
height showed improvement. All 24 patients showed
grade I fusion as per Bridwell Grading on follow-up.
Conclusions: This study shows MIS TLIF for the treatmentof high grades of spondylolisthesis is effective. Patientswith solid fusion and adequate decompression by MIS
techniques can achieve good results. Although larger, prospective randomized controlled trials with longer followup are required to establish long-term results.

PS-FP-11-1

Comparative Study for Navigated Drill andNavigated Probe for Cervical Pedicle Screw
Insertion
Tomoyuki Takigawa, Takuya Morita, Yasuo Ito
Department of Orthopaedic Surgery, Kobe Red Cross Hospital, Kobe, Japan

Purpose: Perforation of the cervical pedicle screw, especially lateral perforation, may lead critical complications,such as vertebral injury. Sub-axial cervical spines (C3–6)
are at risk of complications because these levels have
limited area and angle. The purpose of this study was tocompare navigated drill and navigated probe for insertionof cervical pedicle screws at C3–6.
Methods: A total of 60 cases treated with cervical pedicle
screws at C3–6 was retrospectively investigated. Cervicaltrauma was the main etiology of the surgery (53/60). Thirty cases with 107 cervical pedicle screws using navigateddrill (group D) and 30 cases with 100 cervical pedicle
screws using navigated probe (group P) were compared.
Perforation rate (Neo classification: grade 0, none; grade 1,<2 mm; grade 2, 2–4 mm; grade 3, >4 mm), and the anatomical medial angle of the pedicle and the actual angle ofthe screw were investigated.
Results: Ten cases of grade 1 perforation were identified ineach group. No grade 2 or 3 perforation was found in eachgroup. Perforation rate were 4% (4/101) in group D and
8.2% (8/98) in group P when excluding cases with pedicle
width under 3.5 mm (minimal screw size). All perforations were at medial in group D and at lateral in group P.
There was no statistical difference in the anatomical angleof the pedicle in each group. Mean medial angle of thepedicle screws was 24.2° in group D and 30.9° in group P(p<0.05).
Conclusions: Group D had lower perforation rate andsmaller medial angle than group P. Medial perforationof the cervical screw is believed to be safer than lateralperforation. However, lateral perforation is more common than medical perforation, because the lateral corticalwall is thinner than the medical one, retracted muscles
resist to direct medial, and the insertion torque rotates
the vertebra to the lateral. Navigated drill enable to makea pathway at the hard medial wall of the pedicle which is
impossible even with a navigated probe. Moreover, navigated drill does not require excessive exposure to the lat-

Asian Spine Journaleral nor excessive power while making a pilot hole, which
would be helpful for preventing lateral screw perforation.
Navigated drill can be a useful option for insertion of thecervical pedicle screw because of its easiness and safeness.

PS-FP-11-2

Accuracy of Pedicle Screw Placement in
Early Onset Scoliosis Using Intraoperative
Computed Tomography and Image-Guided
Navigation
Takuya Iimura, Hiroshi Moridaira, Satoshi Inami,
Daisaku Takeuchi, Haruki Ueda, Hiromichi Aoki,
Hiroshi Taneichi
Department of Orthopaedic Surgery, Dokkyo Medical University, Mibu,
Japan

Purpose: Pedicle screws (PS) frequently used for spinal
instrumentation in early onset scoliosis (EOS). High ratesof PS malposition have been reported in EOS. Recently,
intraoperative computed tomography (CT) and imageguided navigation have become available. The purpose ofthis study was to evaluate the accuracy of PS placement in
EOS using intraoperative CT (O-arm) and image-guided
navigation versus conventional freehand technique.
Methods: Between 2007 and 2019, 284 PS were placed in
36 consecutive patients with EOS. Mean age at surgery
was 7.3 years. PS were divided into O-arm navigationgroup (OA group: n=168 PS, 19 patients) and conventional freehand technique group (FH group: n=116 PS,
17 patients). The glade of pedicle perforation and themorphology of pedicle were investigated. Each PS wereassigned a grade of 0 to 3. Grade 0 and 1 penetrations
were considered satisfactory, whereas grades 2 and 3 wereregarded as major perforations. Pedicle width (PW) andleft/right pedicle width ratio (PR) were measured for themorphology of pedicle. The grade of pedicle perforation
was compared between the two groups. The correlations
between the grade of pedicle perforation and the morphology of pedicle (PW and PR) were analyzed. And thecut off value of the morphology of pedicle that causes
grade 2 and 3 perforation was examined.
Results: Grade 0 and 1 penetrations were 166 in OA groupand 102 in FH group. Grade 2 and 3 perforations were 2
in OA group and 14 in FH group. In FH group, the rate ofS149

grade 2 and 3 perforation (12%) was significantly higher
than OA group (1.2%) (p=0.0001). In OA group, the gradeof pedicle perforation and the morphology of pedicle (PW
and PR) were not related. In FH group, the grade of pedicle perforation and PW were not related. But the median
PR of grade 2 and 3 (1.3) was significantly higher thanthat of grade 0 and 1 (1.1) (p=0.0073). In receiver operating curve analysis of the pedicle in major perforation andPR, the cut-off value of PR that causes major perforation
was 1.2 (area under the curve=0.71).
Conclusions: O-arm and image-guided navigation improved the accuracy of PS placement in EOS. Using conventional freehand technique, PS misplacement occurs
because the morphology of pedicles is not correctly recognized in EOS with asymmetrical, malformed vertebral
bodies. O-arm and image-guided navigation are valuable
tools for the safe placement PS in EOS with significant
spine deformity and altered anatomy.

PS-FP-11-3

C-Arm Free Lumbar Interbody Fusion
Keisuke Nakano1, Masaki Mori1, Tomohiro Tominaga1,
Keiji Fujio1, Toshimitsu Kawagishi2, Toshitada Sawada2,
Toshihiro Tanaka2, Sunao Tanaka3, Tohru Asari3,
Kyouta Ishibashi3, Masanori Izeki4
1

Maki Orthopedic Hospital Spine Center, Osaka, Japan
Takaoka Seishikai Hospital, Takaoka, Japan3
Department of Orthopedics, Hirosaki University, Hirosaki, Japan
4
Department of Orthopedics, Kansai Denryoku Hospital, Osaka, Japan
2

Lumbar interbody fusion surgeries (oblique lateral interbody fusion [OLIF], direct lateral interbody fusion[DLIF], transforaminal lumbar interbody fusion [TLIF],
posterior lumbar interbody fusion [PLIF], etc.) have been
well recognized as effective procedures for degenerative
spinal disorders. On the other hands, minimally invasive
spine surgeries have been developed in the recent decades.
However, minimally invasive procedures require the Carm assistance. Since 2015, the authors have used the Oarm (Medtronic) navigation in the minimally invasive
spine surgeries for the degenerative spinal diseases including spine deformity, spine trauma, spinal canal stenosis
and so on. In this paper, the authors describe the benefitsof the O-arm navigation for the minimally invasive spine
fusion surgeries. In this 3 years, 100 cases of spinal defor-

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Asian Spine J 2021;15(Supplement 1):S1-S177

mity associated with lumbar canal stenosis were treatedby OLIF and 200 cases of lumbar canal stenosis including
listhesis and foraminal stenosis were treated by minimallyinvasive TLIF (MIS-TLIF). Both of all cases with OLIF
and MIS-TLIF were operated with the assistance of O-arm
navigation. None of these surgeries were performed withthe assistance of C-arm fluoroscopy. In the OLIF group,
the position of interbody cages (Clydesdale: Medtronic)
on the navigation monitor were compared with postoperative computed tomography (CT). There were somedifferences between navigation monitor and postoperative CT in the depth (5 mm mean) and degree (3° mean)of cage position. In all cases of OLIF and MIS-TLIF, thescrew positions were also compared between navigation
monitor. There were some differences in the depth (3 mmmean) and degrees (2° mean) of screw positions. The malposition of percutaneously inserted pedicle screws were0.8% in this study. So, the accuracy of O-arm navigationis thought to be acceptable. In the fusion surgeries with
O-arm navigation, C-arm shots is not necessary. For thesurgeons, anesthesiologists and all staff in the operating
room, the radiation dosage can be decreased to 0 level inO-arm navigated surgeries. Recently, the occupationalradiation exposure has been the big issue. The surgicalprocedures without fluoroscopy have been preferable. In
conclusion, the O-arm navigation has great benefits forthe treatment with lumbar interbody fusion in the realmof the accuracy and the radiation exposure.

PS-FP-11-4

Robot-Assisted Minimally Invasive Transforaminal
Lumbar Interbody Fusion in the Treatment of
Lumbar Spondylolisthesis
Guanyu Cui, Xiaoguang Han, Yajun Liu, Da He,
Yuqing Sun, Bo Liu, Wei Tian
Department of Spinal Surgery, Beijing Jishuitan Hospital, Beijing, China

Purpose: To compare the clinical efficacy between robotassisted minimally-invasive transforaminal lumbar interbody fusion (robot-assisted MIS-TLIF) and traditional
open TLIF surgery in the treatment of lumbar spondylolisthesis.
Methods: According to the inclusion and exclusion criteria, 48 cases with lumbar spondylolisthesis who received

surgical treatment from Jun 2016 to Dec 2017 in the
Spinal Surgery Department of Beijing Jishuitan Hospitalwere analyzed in this study, including 23 patients who
received robot-assisted MIS-TLIF and 25 patients who
received traditional open TLIF surgery. The two groups
were compared in terms of pedicle screw accuracy evaluated by Gertzbein-Robbins classification on postoperative
computed tomography (CT), operation time, blood loss,
postoperative drainage, hospitalization, time to independent ambulation, low back pain evaluated by Visual Analog Scale (VAS), lumbar function evaluated by Oswestry
Disability Index (ODI), paraspinal muscles atrophy onmagnetic resonance imaging, and complications.
Results: Postoperative CT showed that grade A screws
rate in the robot-assisted MIS-TLIF group was significantly more than that of the open surgery group (χ2=4.698,
p=0.025). Compared with the open surgery group, therobot-assisted MIS-TLIF group had significantly lessintraoperative blood loss, less postoperative drainage,
shorter hospitalization, shorter time to independent
ambulation, and lower VAS at three-dimensional postoperation (p<0.05). However, the duration of surgery was
longer. The VAS of the robot-assisted MIS-TLIF groupdecreased from 6.9±1.8 at preoperation to 2.1±0.8 atpostoperation, 1.8±0.7 at 6-month follow-up and 1.6±0.5
at 2-year follow-up. The VAS of the open surgery groupdecreased from 6.5±1.7 at preoperation to 3.7±2.1 atpostoperation, 2.1±0.6 at 6-month follow-up and 1.9±0.5
at 2-year follow-up. The ODI of the robot-assisted MISTLIF group decreased from 57.8%±8.9% at preoperation to 18.6%±4.7% at postoperation, 15.7%±3.9% at
6-month follow-up and 14.6%±3.7% At 2-year followup. The ODI of the open surgery group decreased from
56.9%±8.8% at preoperation to 20.8%±5.1% at postoperation, 17.3%±4.2% at 6-month follow-up and 16.5%±3.8%
at 2-year follow-up. Paraspinal muscle cross-sectional areain 2-year follow-up in patients of the open surgery groupdecreased significantly than in patients of MIS-TLIF
group (p=0.016).
Conclusions: In the treatment of lumbar spondylolisthesis,
robot-assisted MIS-TLIF may lead to more precise pedicle
screw placement, less intraoperative blood loss, less postoperative drainage, less postoperative pain, quicker recovery, and less paraspinal muscle atrophy than traditional
open surgery.

Asian Spine Journal
PS-FP-11-6

Comparison Between Machine-Vision Image
Guided Surgery System and Robotic Guidance
System for Pediatric Idiopathic Scoliosis Spine
Surgery
Kevin Lim1, Alyssa Toh2, Nicole Lee3
1

Division of Surgery, Department of Orthopaedic Surgery, KK Women’s &Children’s Hospital, Singapore
2
Division of Surgery, KK Women’s & Children’s Hospital, National
University of Singapore, Singapore
3
Division of Surgery, KK Women’s & Children’s Hospital, Singapore

Purpose: Advances in spinal navigation and robotics havetransformed modern spinal surgery. However, there is a
paucity of literature comparing both systems in posterior
spinal fusion (PSF) surgery for idiopathic scoliosis. In
this study, radiation exposure data and other clinical parameters in PSF surgery were compared between a novel
machine-vision image guided surgery (MvIGS) spine
navigation system and a robotic guidance system (RGS).
Methods: A retrospective intraoperative and radiographic
chart review was conducted for all adolescent idiopathic
and juvenile idiopathic scoliosis patients who had undergone PSF in our institution between August 2018 and January 2021. Radiological and clinical data such as numberof fluoroscopy images taken, duration of intraoperative
radiation exposure, total intraoperative radiation dose,
estimated blood loss, operative time per level fused andlength of hospital stay were analyzed.
Results: A total of 26 patients met the inclusion criteria forstudy: 13 patients using MvIGS were compared with 13
patients using RGS. Patients in both groups had the samegender distribution (85% females) and similar mean age(14.8±2.51 years vs. 14.1±1.83 years, p=0.400). Comparedwith patients in the RGS group, the use of MvIGS significantly halved the number of fluoroscopy images taken(20.6±6.74 shots vs. 46.2±15.7 shots, p<0.001), duration of
intraoperative radiation exposure (24.3±8.86 seconds vs.
49.8±18.5 seconds, p<0.001) and estimated blood loss inpatients (515±385 mL vs. 1,080±850 mL, p=0.038). A significant decrease of 62% in total intraoperative radiationdose was also observed in the MvIGS group compared to
the RGS group (73.8±44.4 cGycm2 vs. 194±206 cGycm2,
p=0.05). Both groups had similar total operative time
(376±101 minutes vs. 375±66.7 minutes, p=0.968). While
operative time per level fused was shorter in the MvIGS

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group (34.2±6.83 minutes vs. 36.4±6.56 minutes), alongwith a shorter length of hospital stay (6.54±3.50 days vs.
7.54±2.76 days), the differences were not statistically significant.
Conclusions: Compared with the RGS, the use of MvIGS
required fewer fluoroscopy images intraoperatively, resulting in a significantly shorter duration of radiation
exposure and lower cumulative intraoperative radiation
dose. Blood loss in the MvIGS group was also significantly
reduced compared with patients in the RGS group.

PS-FP-11-7

Safety of Pin Insertion Position for Iliac Reference
Guide in Spinal Navigation
Hiroaki Murakami1, Yasushi Fujiwara1, Ryo Ota1,
Shinji Kotaka1, Hideki Manabe2
1

Department of Orthopedics, Hiroshima City Asa Citizens Hospital,
Hiroshima, Japan2
Department of Orthopedics, Hiroshima Hiramatsu Hospital, Hiroshima,Japan

Purpose: In intraoperative navigation, it is important to
fix the reference guide to the patient’s body safely. During thoracic and lumbar surgery, it is common to insert
two pins into the ilium to insert the reference guide. But,
the certainty and safety of the method have not been
discussed much until now. In this study, we evaluate theinsertion position of the iliac pin for the spinal navigation.
Methods: From December 2019 to October 2020, 48 patients (mean age: 71.2 years old; range, 45–89 years old;
30 males, 18 females) underwent spine surgery assistedwith a Siemens flat panel three-dimensional (3D) C arm
and a Brainlab navigation system with a pin inserted into
the ilium and the reference guide fixed. After the two pins
inserted the iliac wing, we evaluated pin position of theiliac bone by 3D C arm and the presence or absence of
deviation of the pin into the pelvic cavity and spinal canal.
Also, we evaluate number of cortical bones (ilium and sacrum) through which the pin penetrates.
Results: In all cases, the reference guide fixations weregood, and there were no complications during or after
surgery. No obvious deviation into the spinal canal wasobserved, but there were four cases in which deviation
into the spinal canal was borderline. Deviation into thepelvic cavity was observed in six cases, of which four cases

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were within 5 mm and two cases were more than 5 mm.
Regarding the number of cortical bones penetrated by thepin, 11 cases had one cortical bone, 29 cases had two cortical bones, seven cases had three cortical bones, and one
case had four cortical bones in proximal pin. In distal pin,
15 cases had one cortical bone, 25 cases had two corticalbones, eight cases had three cortical bones, and 0 case had
four cortical bones. And the average number of corticalbones penetrated was 2.0 in proximal and 1.9 in distal.
Conclusions: Although it is widely practiced to insert pins
into the ilium in prone spinal surgery, six cases deviatedinto the pelvic cavity and four cases were borderline todeviate into the spinal canal in this study. Fortunately, nocomplications were observed, but there was a risk of damage to the large blood vessels, intestines, and nerves, so weneed take care of pins position.

PS-FP-11-8

O Arm Navigation Assisted Minimally Invasive
Transforaminal Lumbar Interbody Fusion forDegenerative Lumbar Disease: Study of 83
Patients
Rajendra Sakhrekar, Vishal Peshattiwar, Mohan Gawande
Department of Spine, Kokilaben Dhirubhai Ambani Hospital, Mumbai,
India

Purpose: Minimally invasive spine fusion surgery (MIS)
rates has increased as treatment of choice for spinal ailments over last 2 decades. Patient satisfaction, better surgical outcomes, faster recovery, shorter duration of hospital stay, and early return to work has made minimallyinvasive procedures like MIS transforaminal interbody
fusion (MIS TLIF) more popular. This technique of O arm
assisted MIS TLIF has proved decreased rates of postoperative morbidity, dural leaks, and postoperative infection.
This study aims to do analysis the clinical and radiologicaloutcomes of O arm assisted minimally invasive lumbar
fusion techniques for degenerative lumbar ailments.
Methods: From October 2017 to December 2019, 83 patients of Indian population with degenerative lumbar spinal stenosis were evaluated for minimum 1 year in termsof clinical factors like Visual Analog Scale (VAS), Oswestry Disability Index score (ODI), and 36-item Short Form
Health Survey (SF-36) score and radiological factors likefusion rate, disc height, disc angle, and foraminal height
were assessed.
Results: After 1-year follow-up, the patient’s functional
improvement based VAS, ODI, and SF 36 scores was
significant. Radiological outcomes like disc height, discangle, foraminal height showed improvement. The rate ofaccuracy of pedicle screw fixation was 99%
Conclusions: Good functional and radiological outcomescan be achieved with O ARM assisted MIS TLIF. The results are comparable with other fusion techniques.

PS-FP-12-1

Effectiveness of Nitinol in Motion-Preserving
Stabilization of Lumbar Spine
Arkadii Kazmin, Sergey Kolesov, Andrey Panteleev,
Maxim Sazhnev
Department of Spine Pathology, N.N. Priorov National Medical Center,
Moscow, Russia

Purpose: The standard of surgical treatment of lumbar degenerative disc disease is decompression of neural structures of the spinal canal with the instrumentation. However, these interventions lead to a number of complications,such as adjacent segment disease, pseudoarthrosis, andbone resorption around the pedicle screws. Dynamic
stabilization proved to be an effective surgical techniquein our prospective study conducted on 252 patients. All
patients showed significant improvement according to
the Oswestry Disability Index (ODI), 36-item Short Form
Health Survey (SF-36), and Visual Analog Scale (VAS) at
all control periods up to 5 years after surgery.
Methods: We analyzed the results of surgical treatmentof 123 patients with degenerative diseases of the lumbar
spine, who were treated using nitinol rods from 2011 to2017 in our department. The control group consisted of
129 patients, who were treated using standard rigid rods
made of titanium. Taking into account the results of preoperative examination of patients, the tactics of further
surgical treatment were determined, based on which thepatients (n=252) were divided into five groups dependingon the level of fixation. Radiographs, computed tomography, magnetic resonance imaging, and clinical outcomes
were examined preoperatively, and at 6-, 24-, 48-, and60-month follow-up.

Asian Spine Journal
Results: The results were evaluated according to the VAS,
SF-36, and ODI questionnaires. In both cases (rigid anddynamic stabilization), statistically significant improvements were noted in the postoperative period (p<0.01).
In both groups, in comparison with preoperative values,
improvement was observed in all control periods, whichwere highly statistically significant (p<0.01). Assessmentof mobility in the segment stabilized using dynamic nitinol rods demonstrated average conserved range of motions of 4.8°. In total, 16 of the 252 treated patients hadcomplications (6.35%). In the group with dynamic nitinol
rod stabilization, there were five complications (4.0%),
and in the group with rigid rods (11, 8.53%).
Conclusions: Pedicle screw fixation of the lumbosacral
spine with the use of nitinol rods is an effective technology that allows to conserve mobility in the lumbosacral
spine in combination with a stable fixation.

PS-FP-12-2

Is There a Place for Surgical Repair in Adults with
Spondylolysis or Grade I Spondylolisthesis?: A
Systematic Review and Treatment Algorithm
Naresh Kumar1, Sirisha Madhu1, Naveen Pandita1,
Miguel Ramos1, Barry Wei Loong Tan1, Jonathan Tan1,
Keith Lopez1, Dinesh Shree Kumar2, Colum Patrick Nolan31National University Health System, Singapore
Changi General Hospital, Singapore
3
National Neuroscience Institute, Singapore
2

Purpose: Surgical repair is less explored than fusion in
adults with spondylolysis/low-grade isthmic spondylolisthesis, due to associated disc-degeneration with increasing age. We conducted a systematic review to: (1) describe
characteristics of adults suitable for pars-repair, and (2)evaluate effectiveness and safety of pars-repair techniques
in adults.
Methods: This review is in accordance with PRISMAP-guidelines and registered with PROSPERO (CRD
42020189208). Studies in English, including patients≥18-years with spondylolysis/grade-I spondylolisthesis
treated with standard pars-repair techniques, were considered eligible. A systematic search was performed inJune 2020 in PubMed/Embase/Scopus/Web-of-Science
databases. MeSH terms for search were “spondylolysis”

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and “spondylolisthesis”, while free-text words included“pars interarticularis”, “pars defects”, “repair”, “pars repair”, “surgical repair”, “Buck*”, “Scott*”, “Scott wiring”,“modified Scott”, “Morscher*”, “pedicle”, “screw”, “pedicle–
screw–rod-system”, “pedicle–screw–hook-system”, “minimally invasive”, “minimal access”, “endoscopic”, “percutaneous”, “navigation”, “image-guided”, and “robot*”. Searchstrings were developed by combining MeSH and free-text
words using Boolean operators. The abstracts of articles
from four data bases were screened initially by three
independent reviewers. Full-text of shortlisted articles
after removal of duplicates were further screened by threereviewers. Any conflict in article selection was discussed
and resolved. Quality assessment was done using Joanna
Briggs Institute critical appraisal checklist for selection of
final articles. Data was extracted from finalized articles
into an approved template and narrative synthesis was
conducted.
Results: A total of 5,813 articles were retrieved. Initial
screening resulted in identification of 289 articles. Of
these, 111-articles (PubMed [n=34]; Embase [n=51]; Scopus [n=20]; Web-of-Science [n=6]) were available for fulltext review after removal of duplicates. Full-text screening
resulted in exclusion of 64 articles. A final 47 articles including 590 adults were available for data extraction after
quality assessment. A high proportion of patients wereyoung adults (18–35 years, 93%). Male:female ratio was
4.4:1. Lysis defect was primarily bilateral (96.4%) with L5
being the most involved level (68.5%). Majority had nodisc degeneration (84%). Spondylolysis was primary diagnosis in 86%. Diagnostic pars-infiltration test was conducted in 22 studies. Conservative-therapy prior to parsrepair ranged from 3–72 months. Buck’s repair was thecommonest technique (27 studies, n=372), and pedicle
screw-rod method was the least explored. Successful repair was reported in 86% treated with Buck’s and ≥90%
with other techniques. Improvement in pain/functional
outcomes, union rate and rate-of-return to sports washigh and comparable across all techniques. Positive longterm (≥2 years) outcomes were noted in >80% patients.
Complication-rate was 11.9%, with implant loosening accounting for majority of cases.
Conclusions: We have established feasibility, success, safety, and long-term effectiveness of pars-repair in selected
adults with spondylolysis/grade-I spondylolisthesis. We
propose the following parameters for optimizing selectionof adults for pars-repair, regardless of technique: (1) age,

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Asian Spine J 2021;15(Supplement 1):S1-S177

18–45-years, (2) no/minimal disc/facet-degeneration onmagnetic resonance imaging, (3) normal discography, and(4) positive pars-infiltration test.

PS-FP-12-3

A New Surgical Strategy for Type 1 Modic
Change Using Transforaminal Full-Endoscopic
Disc Cleaning Surgery
Kazuya Kishima1,2, Kiyoshi Yagi2,3, Keishi Maruo1,
Toshiya Tachibana1, Masatoshi Morimoto2,
Fumitake Tezuka2, Kazuta Yamashita2, Toshinori Sakai2,
Toru Maeda2, Koichi Sairyo2
1

Department of Orthopaedic Surgery, Hyogo Collage of Medicine,
Nishinomiya, Japan2
Department of Orthopedic Surgery, Tokushima University, Tokushima,Japan
3
Department of Orthopedic Surgery, Nagoya City University, Nagoya, Japan

Purpose: It has been reported that Modic change of thelumbar spine endplate includes three types: edema or
inflammation for type 1, fatty marrow change for type 2,
and sclerotic change for type 3, and type1 Modic change
may be related to the chronic low back pain. The antiinflammatory drugs, and intra-discal injection of steroid
were main treatment. But some cases were resisted conservative treatment and require fusion surgery. The fusion surgery may cause the adjacent degeneration; thus,
motion preservation surgery is better, if possible. We
performed transforaminal full-endoscopic disc cleaning(FEDC) surgery for patient of type 1 Modic change whocomplained chronic low back pain.
Methods: The subjects were five patients, seven intervertebral discs (three males, two females) who underwent
FEDC under local anesthesia at our hospital. Mean age
was 51 years old (32–73). Before surgery, intervertebral
disc block was performed in all cases to confirm reproducibility and effectiveness. In the surgical procedure, acanula is placed on the surface of the intervertebral discby a transforaminal approach, the superior articular process is partially resected for avoid existing nerve injury,
and the canula is inserted into the intervertebral disc, anddisc cleaning and end plate ablation using radiofrequency
are performed. After surgery, antibiotics and anti-inflammatory drugs are taken orally, and semi-rigid corset areprescribed.

Results: The average duration of illness was 10.2 years(3–18 years). The average postoperative follow-up period
is 4.6 months (1–12 months). The affected vertebral bodies were below: L2/L3, 1; L3/4, 1; L4/5, 2; and L5/S1, 3. Asa characteristic of the symptom, all cases complained offorward bending pain and low back pain when they are
waking up. Postoperative low back pain Visual Analog
Scale improved to two or less in all cases.
Conclusions: Type1 Modic change is thought to be one of
the signs of instability, but it also occurs in the intervertebral space without degeneration in young people, and weare considering the possibility of infection.
In all cases, low back pain improved, and some cases inwhich the high signal zone disappeared on magnetic resonance imaging-short tau inversion recovery images wereexperienced, and this is a new surgical strategy for type1
Modic change, which is difficult to treat.

PS-FP-12-6

Does Vertebral Body Tethering Cause Discand Facet Joint Degeneration? A Magnetic
Resonance Imaging Study with Minimum
2-Year Follow-up
Caglar Yilgor1, Altug Yucekul1, Burcu Akpunarli2,
Atahan Durbas3, Tais Zulemyan4, Irem Havlucu4,
Gokhan Ergene5, Sahin Senay6, Pinar Yalinay Dikmen7,
Sule Turgut Balci8, Ercan Karaarslan9, Yasemin Yavuz10,
Ahmet Alanay1
1

Department of Orthopaedics and Traumatology, Acibadem University
School of Medicine, Istanbul, Turkey
2
Urla State Hospital, Izmir, Turkey
3
Acibadem University School of Medicine, Istanbul, Turkey
4Comprehensive Spine Center, Acibadem University Maslak Hospital,
Istanbul, Turkey
5
Operating Room Services, Acibadem University Vocational School of Health
Sciences, Istanbul, Turkey
6
Department of Cardiovascular Surgery, Acibadem University School of
Medicine, Istanbul, Turkey
7
Department of Neurology, Acibadem University School of Medicine,
Istanbul, Turkey
8
Anesthesiology Service, Acibadem University Maslak Hospital, Istanbul,
Turkey9Department of Radiology, Acibadem University School of Medicine,
Istanbul, Turkey
10
Department of Biostatistics, Ankara University Faculty of Medicine,
Ankara, Turkey

Purpose: Disc health after various growth modulation

Asian Spine Journal
techniques have been assessed in animal models, andtethering was claimed to prevent degeneration due to its
less rigid nature compared to other growth-friendly techniques. Yet, the results of animal studies wherein tethering
is applied on healthy spines to create a deformity cannot
be extrapolated to humans, in which tethering is used for
deformity correction. As biomechanical properties are different, effects of vertebral body tethering (VBT) in clinicalseries are not precisely acknowledged. There are concernsthat VBT may cause degeneration at intermediate and adjacent levels.
Methods: Retrospective analysis of prospectively collected
data. Demographic, perioperative and radiographic data
were collected. Overcorrection, mechanical and pulmonary complications, and reoperations were recorded.
Magnetic resonance imaging (MRIs) taken before surgery
and at ≥2 years follow-up were evaluated for degeneration
at the intermediate and adjacent segment discs and facet
joints by a blinded senior radiologist. Discs were assessedusing Pfirrmann grade. Facet joint degeneration was graded on a scale of 0–3. Changes from preoperative to followup MRIs were analyzed using McNemar’s test and related
samples marginal homogeneity test.
Results: A total of 25 (23 females, 2 males) consecutive adolescent idiopathic scoliosis patients with a mean followup of 29 (24–62) months who underwent thoracoscopic
VBT between 2014 and 2017 were included. The mean
age at surgery was 12.2 (10–14) years and median Sanders
stage was 3 (1–7). A mean of 7.7±1.1 (6–11) levels were
tethered. Preoperative mean height of 155.3 (130–178) cm
was increased to 163.4 (149–187) cm at latest follow-up.
The mean preoperative main thoracic curve magnitude of
46º±7.7º was corrected to 23.3º±5.9º at first erect, which
was modulated to 12º±11.5º during follow-up. There was 1(4%) broken tether, 5 (20%) overcorrected curves, 3 (12%)
implant-related complications, and 1 (4%) reoperation fora thoracoscopic tether release before the follow-up MRI
was obtained. A total of 217 levels of discs and bilateralfacet joints, were evaluated in the preoperative and followup MRI images. Analyses of disc and facet scores revealed
no significant differences between patients. One case (4%)
that had an increase in disc scores, already had multi-level
moderate degeneration preoperatively, while another case(4%) displayed a single-level new-onset grade-2 bilateralfacet degeneration.
Conclusions: This study reports MRI findings of 25 adolescents (Sanders 2–7) who had undergone thoracoscopic

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VBT surgery. At an average of 29 months (24–62) after
growth modulation, radiographic degenerative findings
were not present in 97.7% of the intermediate and adjacent discs and 99.3% of the facet joints. Studies with longer follow-up are warranted.

PS-FP-12-7

Is Thoracoscopic Vertebral Body Tethering aPulmonary Function Declining or Improving
Surgery?
Caglar Yilgor1, Burcu Akpunarli2, Altug Yucekul1,
Kadir Abul3, Peri Kindan4, Gokhan Ergene5, Sahin Senay6,
Tais Zulemyan7, Yasemin Yavuz8, Ahmet Alanay1
1

Department of Orthopaedics and Traumatology, Acibadem University
School of Medicine, Istanbul, Turkey
2
Urla State Hospital, Izmir, Turkey
3
Clinic of Orthopedics, Istanbul Basaksehir City Hospital, Istanbul, Turkey
4
Acibadem University School of Medicine, Istanbul, Turkey
5
Operating Room Services, Acibadem University Vocational School of Health
Sciences, Istanbul, Turkey
6
Department of Cardiovascular Surgery, Acibadem University School of
Medicine, Istanbul, Turkey
7Comprehensive Spine Center, Acibadem University Maslak Hospital,
Istanbul, Turkey
8
Department of Biostatistics, Ankara University Faculty of Medicine, Ankara,
TurkeyPurpose: Previous studies have shown that anterior spinal
fusion significantly decreased forced vital capacity (FVC)%and forced expiratory volume in 1 second (FEV1)% after
scoliosis surgery in adolescents. Similar concerns wereraised for thoracoscopic vertebral body tethering (VBT),
which, as an anterior technique, may cause deteriorationin pulmonary function.
Methods: Data were collected preoperatively, at 6 weeks, 1
year, 2 years, and latest follow-up. All-thoracoscopic technique was used to approach thoracic vertebra, while retroperitoneal approach was used to access lumbar vertebra.
Demographic, clinical, radiographic data, and complications were analyzed. Curve sizes at each follow-up werecompared using repeated-measures analysis of variance.
Preoperative, 1-year, and 2-years postoperative FEV1%and FVC% were compared using paired-sample t-test in
thoracic group and Wilcoxon test for thoracolumbar anddouble-curve groups.
Results: A total of 54 (51 females, three males) consecutive adolescent idiopathic scoliosis patients with a mean

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Asian Spine J 2021;15(Supplement 1):S1-S177

age of 12.4±1.5 years, and a mean follow-up of 31 (24–57)
months who underwent thoracoscopic VBT between
2014–2018 were included. Patients (78%) were Lenke 1(19 A, 6 Ar, 13 B, and 4 C modifiers) and there were one,
two, six, and two patients with Lenke 2, 3, 5 and 6 patterns, respectively. Preoperatively, 30 (58.8%) patientswere premenarchal (median Sanders: 3 [1–7], Risser: 0[0–5]). A median of 7 (5–11) levels was tethered. Patients
grew 7 cm on average. 87% of the patients reached skeletal
maturity. The mean preoperative nain thoracic curve of
48º±9.4º was corrected to 24.7º±7.2º at first erect, which
was modulated to 16.1º±12.4º during follow-up. A total of
6 (11.1%) patients experienced pulmonary complications(2 ipsilateral and 1 contralateral atelectasis, 1 lobar atelectasis, 1 pleural effusion, and 1 chylothorax). Thoracic VBTresulted in significantly improved pulmonary function at
1-year (mean FVC%, 79.6 to 85.2, p=0.014; mean FEV1%,
80.1 to 87.8, p=0.001). No difference was observed between 1- and 2-year follow-up (final mean FVC% 87.5 andfinal mean FEV1% 90). Thoracolumbar and double-curve
VBT; however, were similar between preoperative and1-year follow-up (mean FVC%, from 81.8 to 83.7; mean
FEV1%, 82.7 to 86.5 for thoracolumbar and mean FVC%,
82.2 to 82.6; mean FEV1%, 82.4 to 85.7 for double-curve).
Conclusions: This study reports the effects of thoracic,
thoracolumbar, and double-curve VBT on pulmonary
functions for 54 consecutive patients with a mean followup of 31 months. As an anterior approach, thoracoscopic
VBT surgery did not have detrimental effects on pulmonary function in short-term follow-up. Thoracic-only
VBT surgery resulted in improved pulmonary function at
1-year, which was preserved at 2-year follow-up. Thoracolumbar and double-curve VBT surgeries did not cause
worsening in pulmonary at 1-year follow-up.

PS-FP-12-8

Two- to 5-Year Follow-up Results After Thoracoscopic Vertebral Body Tethering: A Single
Surgeon’S Experience
Caglar Yilgor1, Altug Yucekul1, Kadir Abul2,
Ilkay Karaman3, Atahan Durbas3, Tais Zulemyan4,
Gokhan Ergene5, Sahin Senay6, Sule Turgut Balci7,
Pinar Yalinay Dikmen8, Yasemin Yavuz9, Ahmet Alanay1
1

Department of Orthopaedics and Traumatology, Acibadem University
School of Medicine, Istanbul, Turkey
2
Clinic of Orthopedics and Traumatology, Istanbul Basaksehir City Hospital,
Istanbul, Turkey
3
Acibadem University School of Medicine, Istanbul, Turkey
4Comprehensive Spine Center, Acibadem University Maslak Hospital,
Istanbul, Turkey
5
Operating Room Services, Acibadem University Vocational School of Health
Sciences, Istanbul, Turkey
6
Department of Cardiovascular Surgery, Acibadem University School of
Medicine, Istanbul, Turkey
7
Anesthesiology Service, Acibadem University Maslak Hospital, Istanbul,
Turkey8
Department of Neurology, Acibadem University School of Medicine,
Istanbul, Turkey
9
Department of Biostatistics, Ankara University Faculty of Medicine, Ankara,
TurkeyPurpose: There is a paucity of information on clinicaland radiographical outcomes of vertebral body tethering(VBT). Current information is not yet strong enough toconvince surgeons to include this surgical technique totheir armamentarium.
Methods: Retrospective analysis of prospectively collected
data. Data were collected preoperatively, at 6-week, 1-year,
2-year, and latest follow-up. Demographic, perioperative, clinical, radiographic data, and complications wereanalyzed. Curve sizes at each follow-up were comparedusing repeated-measures analysis of variance. Respiratory
function was compared between preoperative, 1 year, and2 years postoperative.
Results: A total of 42 (40 females, two males consecutive
adolescent idiopathic scoliosis patients with a mean age of
12.1±1.5 years at surgery, and a mean follow-up of 33 (24–62) months who underwent thoracoscopic VBT between
2014–2018 were included. 95% of the patients showed
Lenke 1 pattern (21 A, 4 Ar, 11 B, and 1 C modifier) and
5% were Lenke 2. Preoperatively, 25 (62.5%) patients werepremenarchal (median Sanders: 3 [1–7], median Risser: 1[0–5]). A median of 7 (6–9) levels was tethered. Mean surgical time was 240±70 (123–360) minutes. Patients grew 8

Asian Spine Journal
cm on average; height measurements showing significant
increase at each follow-up time point (p<0.001). Patients(88%) reached skeletal maturity at final follow-up. Upper
thoracic (UT), main thoracic (MT), and thoracolumbar/
lumbar (TLL) curves showed significant decrease at eachfollow-up time point. No significant changes were notedin kyphosis and lordosis (p<0.05). Forced vital capacity (FVC)% and forced expiratory volume in 1 second(FEV1)% showed significant increase from preop to 1
year, as well as from 1 to 2 years (mean FVC% 80.5, 85.2,
and 87.6, respectively; mean FEV1% 80.5, 87.8, and 90.4,
respectively, p<0.001). Pulmonary, mechanical and curve
behavior complications rates were 12%, 19%, and 33%, respectively. Two patients (4.8%) were converted to fusion.
At final follow-up, 92% patients had ≤30° residual curve.
The Scoliosis Research Society-22 mental health, selfimage and subtotal scores increased significantly.
Conclusions: This study reports a single European center experience on 42 consecutive patients with ≥2-years
follow-up who had undergone thoracic-only VBT surgery.
Surgical correction was followed by growth-dependent
correction attained during follow-up. Spontaneous correction was also noted in the non-operated upper thoracic andthoracolumbar levels. Pulmonary function showed a gradual increase. Thoracoscopic VBT surgery prevented fusion
in 95% of patients of whom 92% had good radiographic(≤30° residual curve) and clinical outcomes; however, it is
not without complications. Overall pulmonary, mechanical and curve behavior complications rates were 12%, 19%,
and 33%, respectively. Some complications may be avoided
with a better understanding of the growth modulation andadvancement of technical skills and technology.

PS-FP-12-9

Clinical and Radiographic Outcome at 7
Years of Follow-up after Cervical Total Disc
Replacement
Kushal Ramesh Gohil, Saumyajit Basu
Department of Spine Surgery, Kothari Medical Center, Kolkata, India

S157

Methods: A total of 32 patients (male:female, 22:10; meanage, 39.9 years; range, 29–55 years) who were treated withsingle-level CTDR between 2009 to 2013 were retrospectively analyzed. The records of clinical and radiologicalexaminations were assessed preoperatively and postoperatively at 1-, 5-, and 7-year follow-up (FU). Clinicalscores outcome included scores such as Neck Disability
Index (NDI), Visual Analog Scale (VAS)-arm and neck
pain. The radiological outcome variables included rangeof motion of implanted prosthesis between maximum
flexion-extension radiographs, radiographic heterotopic
ossifications (HO), and adjacent segment disease (ASD).
Complications and revision surgeries were also explored.
Results: All the clinical outcome scores were statisticallysignificant at any time during FU period. At 7-year FU,
mean improvement was NDI (26–6), VASarm (6.3–2),
VASneck (6.6–2.2) (p<0.05). An increase in the incidenceof HO was seen during postoperative course. Grade 4
HO with solid fusion (9.38%), grade 3 (18.75%), grade 2(25%), grade 1 (37.5%), and grade 0 (9.38%). There wasno significant correlation between HO and clinical scores.
The prosthesis mobility declined from 9.2° preoperatively
to 9° at 1-year FU and 7.5° and 7.3° at 5- and 7-year FU.
Radiographic ASD was seen in 11/32 (34.37%); however,in only 3/32 (9.38%) had clinical symptoms which weremanaged conservatively. There was a positive correlation
between poor device mobility and occurrence of ASD and
ASD appeared earlier in cases with grade 3 or 4 HO.
Conclusions: In this study, favorable 7-year FU clinicaland radiological outcomes were observed. Clinically motion restricting HO was associated with higher ASD.

PS-FP-13-1

Fully-Automated Deep Learning Predictionof Spinal Deformity Alignment Irrespectiveof Image Quality Obtained via Smartphone
Photographs
Jason Pui Yin Cheung1, Yifei Li2,
Kenneth Kwan Yee Wong2, Teng Zhang1
1

Purpose: This retrospective study was done to investigate long term efficacy of cervical total disc replacement(CTDR) with regards to its clinical and radiological outcome.

Department of Orthopaedics and Traumatology, The University of Hong
Kong, Hong Kong
2
Department of Computer Science, Faculty of Engineering, The University ofHong Kong, Hong Kong

Purpose: For facilitating communication, it is popular for

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Asian Spine J 2021;15(Supplement 1):S1-S177

spine specialists to take photos of radiographs with smartphones. An automatic tool to accurately detect vertebral
landmarks and alignment provides easy and highly useful
information for surgeons. Original X-rays are not easily
accessible for telemedicine and existing deep learningbased automated Cobb angle (CA) predictions are notaccurate on suboptimal quality X-rays. The aim of study
was to develop an automated CA prediction system irrespective of image quality, with no restrictions on curve
patterns to facilitate clinical practice and telemedicine.
Methods: A total of 367 consecutive patients attending ascoliosis clinic were recruited prospectively and their coronal X-rays were re-captured using mobile phones. Fivefold cross-validation was conducted (five experiments,
each with 294 images to train a deep neural network
named Spine_HRNet for endplates landmarks and endvertebrae detection, and the remaining 73 images wereused to test). The predicted heatmaps of the vertebral
landmarks were visualized to enhance interpretability of
Spine_HRNet. Per-landmark-absolute-errors and recall of
the landmark detection results were calculated to assess
the accuracy of the predicted landmarks. Further calculated CAs were quantitatively compared with the spine
specialists measured ground truth (GT).
Results: The average per-landmark absolute distance error
and the recall of the detected endplates landmarks were
2.8 pixels and 0.99, indicating a highly accurate detection.
The predicted CAs were all significantly correlated withGT (p<0.01). Compared with GT, the mean error was
3.73°–4.15° and standard error of the measurement was
0.8°–1.7° for the predicted CAs at different spinal regions.
Conclusions: This is the first study using Spine_HRNet
on non-original X-rays to automatically and accurately
predict vertebral landmarks of the scoliotic spine. Spine_
HRNet’s applicability is evidenced by our thorough crossvalidation, which can be used with telemedicine to facilitate fast reliable auto-diagnosis and follow-up.

PS-FP-13-3

Evaluation of the Basal Metabolism of Degenerative
Lumbar Intervertebral Discs Based on
Pfirmann Grade and Presence of Instability
Chaiyapruk Pundee1, Naomi N. Lee2, Jacob S. Kramer2,
Aaron M. Stoker2, Christina L. Goldstein2, Don K. Moore2,
Theodore J. Choma2, James L. Cook2
1

Department of Orthopaedic Surgery, Samitivej Srinakharin Hospital,
Bangkok, Thailand
2
Missouri Orthopedic Institute, University of Missouri, Columbia, MO, USA

Purpose: Intervertebral disc (IVD) degeneration is implicated in back pain, a leading cause of spine-related
disability. It may also cause segmental instability. Bothlocal and systemic inflammatory processes have been
implicated in the pathophysiology of IVD degeneration,
though it is unclear if Pfirmann grade severity or presenceof instability affects degenerative IVD metabolism. These
differences have not previously been investigated. Hence,
this study was designed to examine the basal metabolism of degenerative lumbar IVD tissues collected frompatients undergoing lumbar microdiscectomy or fusion
with the hypothesis that tissues from patients with higher
Pfirmann grades and those with instability would produce
significantly higher levels of degradative enzymes and inflammatory mediators.
Methods: Degenerative IVD tissue excised as part ofa standard-of-care spinal surgery, was obtained frompatients (n=7; mean age, 53, 4 female) being treatedfor symptomatic degenerative lumbar IVD disorders.
Pfirmann grading (1–5) of the IVD was determined byevaluation of magnetic resonance imaging (grade 3, n=3;
grade 4, n=4), and for instability as defined by the presence of a spondylolisthesis on upright lateral radiographs(unstable, n=2; stable, n=5). Tissues comprised of degenerative nucleus pulposus (NP) was collected and explants
were created. Cultured for 3 days, after which media werecollected for biomarker evaluation. Media analyses: Media were tested for monocyte chemoattractant protein(MMP)-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9,
MMP-13, tissue inhibitor of metalloproteinase (TIMP)1, TIMP-2, TIMP-3, TIMP-4, growth-related oncogene(GRO)-α, monocyte chemoattractant protein (MCP)-3,
platelet-derived growth factor (PDGF)-AA, PDGF-AB/
BB, interleukin (IL)-2, IL-4, IL-6, IL-8, MCP-1, macrophage inflammatory protein (MIP)-1α, MIP-1β, RANTESAsian Spine Journal(regulated on activation, normal T cell expressed andsecreted), tumor necrosis factor (TNF)-α, and vascularendothelial growth factor (VEGF) using commerciallyavailable assays. Statistical analysis: Significant differences
between groups were determined by t-test or rank sum
test with significance set at p≤0.05.
Results: No significant differences between basal biomarker production by degenerative IVD tissues of Pfirmann
grade 3 versus 4 discs. However, tissues from degenerative
IVDs with instability were found to produce significantly
higher levels of MMP-8, and significantly lower levels of
MMP-1, MMP-2, and MMP-13 compared to tissues fromstable degenerative IVDs.
Conclusions: No significant difference in the metabolismof IVD tissues with a Pfirmann grade of 3 or 4. However,the presence of instability in the degenerated lumbar IVD
resulted in a significant increase in the production of
MMP-8, but the production of other degradative enzymes
was significantly decreased. Further study is required todetermine in IVD architecture relates to changes in tissue
metabolism, and its pathophysiology may provide insight
into potential therapies for prevention and treatment oflumbar intervertebral disc degeneration.

PS-FP-13-4

Basal and Cytokine-Stimulated Biomarker
Production by Degenerative Lumbar Discs
from Microdiscectomy versus Interbody
Fusion Patients
Chaiyapruk Pundee1, Theodore J. Choma2,
Jacob S. Kramer2, Aaron M. Stoker2,
Christina L. Goldstein2, Don K. Moore2, Naomi N. Lee2,
James L. Cook2
Spine & Joints Center, Department of Orthopaedic Surgery, Samitivej
Srinakharin Hospital, Bangkok, Thailand
2
Missouri Orthopedic Institute, University of Missouri, Columbia, MO, USA
1

Purpose: Intervertebral disc (IVD) degeneration is implicated in back pain, a leading cause of a spine-related
disability. Both local and systemic inflammatory processes
have been associated with IVD degeneration, though it
is unclear if differences between these processes exist in
degenerative IVDs of patients undergoing lumbar microdiscectomy versus lumbar interbody fusion. Hence, thisstudy was designed to examine basal and cytokine-stim-

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ulated metabolic responses of degenerative lumbar IVD
tissues collected from patients undergoing lumbar microdiscectomy or interbody fusion with the hypothesis thattissues from patients undergoing fusion would produce
significantly higher levels of degradative enzymes andinflammatory mediators under both basal and cytokinestimulated conditions when compared to tissues frommicrodiscectomy.
Methods: Degenerative IVDs excised as part of a standardof-care spinal surgery, lumbar microdiscectomy (n=3) or
fusion (n=4) surgery was obtained from patients (n=7;mean age, 53, 4 female). Tissues comprised of nucleus
pulposus (NP) was collected. Two explants per disc wererandomly assigned to the 10 ng/mL interleukin (IL)-1β
stimulation group (IL) or the untreated basal metabolism
group (BASAL). Tissues were cultured for 3 days, after
which media were collected for biomarker evaluation.
Media analyses: Media were tested for monocyte chemoattractant protein (MMP)-1, MMP-2, MMP-3, MMP7, MMP-8, MMP-9, MMP-13, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, TIMP-3, TIMP-4, growthrelated oncogene (GRO)-α, monocyte chemoattractant
protein (MCP)-3, platelet-derived growth factor (PDGF)AA, PDGF-AB/BB, IL-2, IL-4, IL-6, IL-8, MCP-1, macrophage inflammatory protein (MIP)-1α, MIP-1β, RANTES(regulated on activation, normal T cell expressed andsecreted), tumor necrosis factor (TNF)-α, and vascularendothelial growth factor (VEGF) using commerciallyavailable assays. Statistical analysis: Significant differences
between groups were determined by t-test using SPSS
with significance set at p≤0.05.
Results: In the BASAL group, only the production of
MMP-8, TIMP-4, and PDGF AA was significantly higher
in the IVD tissues from the fusion cohort compared tothat from the microdiscectomy group. In response to cytokine stimulation with IL-1β, tissues in the fusion groupresponded with significantly greater production of TIMP2, TIMP-4, PDGF-AA, IL-6, IL-8, MIP-1β, and VEGF
when compared to the response by the tissues from themicrodiscectomy patients.
Conclusions: Basal inflammatory and degradative metabolism of degenerative lumbar IVD tissues collected frommicrodiscectomy versus fusion patients was not significantly different, since MMP-8 and TIMP-4 were the only
biomarkers significantly different between the two patientgroups. Tissues from the lumbar fusion patients do appear
to be more sensitive to cytokine stimulation compared toS160

Asian Spine J 2021;15(Supplement 1):S1-S177

those from the microdiscectomy. The biochemical processes and clinical significance require further study. A
deeper understanding of this phenomenon may provide
insight into potential therapies for prevention and treatment of lumbar intervertebral disc degeneration.

PS-FP-13-5

Ubiquitin Mediated Proteasome Degradation
Leading to Glutamic Acid Accumulation Could
Be the Cause for Poor Clinical Outcomes inPatients with Modic Changes
Dilip Chand Raja Soundararajan1,
Sharon Miracle Nayagam2, Chitraa Tangavel2,
Sri Vijayanand K. S.1, Raveendran Muthurajan3,
Ajoy Prasad Shetty1, Rishi Mugesh Kanna1,
Rajasekaran Shanmuganathan1
1

Department of Spine Surgery, Ganga Hospital, Coimbatore, India
Department of Proteomics, Ganga Research Centre, Coimbatore, India
3
Department of Plant Biotechnology, Tamil Nadu Agricultural University,
Coimbatore, India
2

Study Design: Experimental analysis.
Purpose: This study aimed to investigate the biologicalbasis of this poor outcome, to investigate the basis of inflammation and probe the possibility of sub clinical infection as an etiology of Modic changes (MC). We also aim
to identify biological biomarkers and potential targets formolecular therapy.
Overview of Literature: Patients with MC form a distinct
clinical subset with higher intensity of pain, poor clinicaland surgical outcomes, and higher incidence of recurrence. MC also is an independent risk factor for increased
postoperative surgical site infection.
Methods: Nucleus pulposus (NP) from 24 patients undergoing microdiscectomy for disc herniation (14 discs
with MC and 10 without Modic changes [NMC]) were
procured. The overall expression of proteins, biologicalprocesses, protein-protein, and metabolite interactions
were analyzed and compared. The role of bacterial infection was investigated by documenting the host defense
response proteins (HDRPs) and immunological pathways
activated in patients with MC.
Results: Label-free proteomic approach with stringent
filters revealed a total of 208 proteins in MC and 193 in
NMC groups. Forty-five proteins were specific to MC(30) to NMC and 163 common to both. Downregulated
proteins in MC belonged to components of extracellularmatrix such as collagens (COL- 6A1, 6A2, 6A3, 11A1,
12A1, and 20A1), and proteoglycans (versican [VCAN],
and biglycan [BGN]). Inflammatory molecules (plasminogen [PLG], angiogenin [ANG], fibroblast growth
factor-binding protein 2 [FGFBP2], tetranectin [CLEC3B],
cartilage acidic protein 1 [CRTAC1], kininogen [KNG-1],
chitinase-3-like protein 2 [CHI3L2], and ferritin [FTL])
were expressed only in the MC group. The significantly altered pathways in MC included Fc fragment of immunoglobulin G receptor IIIa (FCGR3A)-mediated phagocytosis, regulation of toll-like receptors by endogenous ligand,neutrophil, and platelet degranulation.
Conclusions: Our study confirms that MC represents anintense inflammatory status with probable basis of bacteria induced host defense response and immune activation. Downstream effects leading to ubiquitin mediatedproteasomal degradation of extracellular matrix proteins
and the resulting metabolites such as glutamic acid could
be the possible cause of poor outcomes in these patients.
Documenting the expression of inflammatory molecules,
immune mechanisms and host defense response proteinssuggests a bacterial role in pathological mechanisms ofMC and its associated poor outcome. Further, ubiquitin
mediated proteasomal degradation and accumulation of
glutamate in discs with MC might serve as targets for molecular therapy to improve clinical/surgical outcomes inthese patients.

PS-FP-13-6

Histopathological and Cytogenetic Analysis ofLumbar Epidural Lipomatosis
Taketoshi Yasuda1, Kayo Suzuki1, Shoji Seki1,
Kenta Watanabe1, Hiroto Makino1, Takeshi Hori2,
Masahiko Kanamori3, Yoshiharu Kawaguchi1
1

Department of Orthopaedic Surgery, University of Toyama, Toyama, Japan
Department of Orthopaedic Surgery, Kurobe City Hospital, Kurobe, Japan3
Department of Human Science 1, University of Toyama, Toyama, Japan
2

Purpose: Spinal epidural lipomatosis (SEL) is characterized by the abnormal accumulation of unencapsulated
adipose tissue in the spinal epidural space. Lumbar epidural lipomatosis (LEL) is found in 39%–42% of patients

Asian Spine Journal
with SEL, and L4–5 is the most commonly involved level.
Symptomatic LEL occurs in middle age and is most often
seen in men. Lipomas are common and can occur anywhere in the body, but spinal lipomas rarely occur. In bothspinal lipoma and LEL, histopathological findings show
mature adipocytes that vary only slightly in size and shapeand have small, eccentric nuclei. It is difficult to distinguish between spinal lipoma and LEL by histopathologicalfindings alone. Therefore, additional diagnostic tools arenecessary to distinguish between true spinal lipoma andLEL. To date, cytogenetic studies of LEL have not beenreported. The purpose of this study was to elucidate thehistopathological and cytogenetic characteristics in patients with LEL who had undergone decompressive spinal
surgery.
Methods: Six patients undergoing decompressive spinal
surgery (all men; mean age, 71.3 years) were enrolled between 2011 and 2015. Three cases were steroid-induced
and three cases were diagnosed as idiopathic LEL. All
patients presented with neurological deficits in the lower
extremities, with cauda equina syndrome (CES) in 4 cases, radiculopathy and CES in one case, and radiculopathy
in one case. We compared the differences in histologicalmorphology between the subcutaneous fat tissue andepidural fat tissue in each patient. We also analyzed the
karyotype of resected epidural lipomatous tissue using the
G-band method.
Results: The epidural adipocytes were histologically more
irregular and smaller compared with the subcutaneous
adipocytes in all cases. The mean size of subcutaneous adipocytes and epidural adipocytes was 5,485.6±2,584.1 μm2
and 2,705.4±1,069.1 μm2, respectively. In all cases of both
idiopathic and secondary LEL, the loss of chromosome Y
was seen on cytogenetic analysis.
Conclusions: The mechanisms related to the developmentof LEL are not well understood. Although all of the patients in our study were men, we believe the loss of the Y
chromosome might contribute to the development of LEL.
Although both histological changes of epidural adipocytes
and loss of the Y chromosome may be effects rather thancauses, these findings may be related to the onset and development of LEL.

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PS-FP-13-7

Prolonged Use of Narcotics after Spine Surgery:
A Requirement or a Privilege
Muhammad Tahir Karim, Shehar Yar Abid, Shahid Ali
Orthopaedic Surgery Unit-1, Jinnah Hospital, Lahore, Pakistan

Purpose: The purpose of this study was to find out if thenarcotic analgesics are really required as much as they areusually prescribed after spine surgeries or do, they justwork as a privilege for the patients and the surgeon.
Methods: This is a retrospective observational study. The
study utilized the data of 89 patients between the ages of
25 to 65 years operated from October, 2019 to June, 2020.
Adults who underwent one of four common spinal surgical procedures (discectomy, decompression, lumbar posterolateral fusion, or lumbar interbody arthrodesis) were
included in the study while patients with causes of pain
other than spine were excluded. Patients were discharged
on combination of Paracetamol (325 mg) and Tramadol(HCl, 37.5 mg) twice daily per oral and the patients wereassessed at 2-, 4-, and 8-week intervals. Patients were assessed about the need of narcotics use after the specified
period of time. The collected data was then analyzed in
IBM SPSS ver. 25.0 (IBM Corp., Armonk, NY, USA).
Results: Out of total 89 patients included in the study,
31 (34.8%) were males while 58 (65.16%) were females.
Thirty-one of the patients underwent lumbar discectomy,
25 patients underwent decompression, 21 patients underwent lumbar interbody arthrodesis, and 12 patients
underwent lumbar posterolateral fusion. Some patients(87.64%) didn’t feel the need to continue the narcotic pain
killers after 2 weeks of operation. Only 12.36% of the subjects required to continue the narcotics for 4 weeks after
surgery.
Conclusions: After 2 weeks of surgery, nearly all patients
had discontinued opioid use. These results indicate thatspine surgery among opioid-naive patients is not a major driver of long-term narcotics use especially in Asian
countries like Pakistan. On the contrary, these narcotics
are luxuriously given to patients in the western countries.
Main reasons being in developing countries like Pakistan,
the bill of these medicines has to be covered by the patients themselves and not by health insurance companies.
Additionally, the addiction to drugs, alcohol and othercentral nervous system suppressing agents is also less

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Asian Spine J 2021;15(Supplement 1):S1-S177

prevalent in Pakistan. Hence, prolonged and avoidable useof narcotics after spine surgery is more of a privilege thana requirement.

PS-FP-13-8

at the upper lumbar spine and depended on the contour
and material of rods.

PS-FP-13-9

Posterior Rod Strain in a Long Spinal Fusion
to the Pelvis: An In-Vitro Experimental Study
Using Synthetic Lumbopelvic Bone Models

The Possible Involvement of the Oxidized
LDL/LOX-1 System in Ligamentum Flavum
Hypertrophy in the Patients with Lumbar
Spinal Canal Stenosis

Shunji Tsutsui1, Ei Yamamoto2, Takuhei Kozaki1,
Akimasa Murata1, Hiroshi Yamada1

Sota Nagai1, Hiroki Takeda2, Daiki Ikeda1, Soya Kawabata1,
Kota Watanabe3, Shinjiro Kaneko2, Nobuyuki Fujita1

1

1

Department of Orthopedic Surgery, Wakayama Medical University,
Wakayama, Japan2
Department of Biomedical Engineering, Faculty of Biology-Oriented Scienceand Technology, Kindai University, Higashiosaka, Japan

Purpose: Despite the improvement in surgical techniques
and instruments, there are still high rates of rod fracture(RF) associate in a long spinal fusion, especially in thetreatment of adult spinal deformity (ASD). Thus, improved understanding of RF could be valuable for surgicalplanning. The aim of this study is to investigate mechanical stress on posterior rods in the setting of lumbopelvic
fixation for the recent treatment of ASD.
Methods: Synthetic lumbopelvic bone models were instrumented with intervertebral cages, pedicle screws and S2alar-iliac screws, and rods. The construct was placed in a
testing device, and compressive loads were applied. Strain
on the rods was measured using strain gauges on the dorsal aspect of each rod.
Results: When the models were instrumented using titanium alloy rods with the contour of 30º and lateral interbody cages, posterior rod strain was significantly higher
in the lower segment (L5/S1) than in the upper segment(L2/3) (p=0.009). Changing rod contour from 30º to 50º
caused a 36% increase in strain in the lower segment (L5/S1). Changing rods from titanium alloy to cobalt-chromium caused a 140% increase in strain in the upper segment(L2/3), whereas a 28% decrease in strain in the upper segment (L5/S1). Using transverse fixators or changing cages
from laterally-placed to posteriorly-placed ones did not
add significantly additional rod strain in any of the segments.
Conclusions: In the setting of lumbopelvic fixation using
currently available surgical techniques for ASD, the posterior rod strain was larger at the lumbosacral junction than

Department of Orthopadics Surgery, Fujita Health University, Toyoake,Japan
2
Department of Spine and Spinal Cord Surgery, Fujita Health University,
Toyoake, Japan3
Department of Orthopadics Surgery, Keio University School of Medicine,Tokyo, Japan

Purpose: The patients with lumbar spinal canal stenosis (LSS) patients often have arteriosclerosis. Oxidized
low-density lipoprotein (LDL) is clinically known to be
involved in the development of arteriosclerosis throughlectin-like oxidized LDL receptor-1 (LOX-1) binding.
Here, we aimed to elucidate the potential involvement ofoxidized LDL/LOX-1 system in ligamentum flavum (LF)
hypertrophy.
Methods: Forty-five samples were collected from LF tissues of the patients who underwent posterior lumbar spinal surgery for LSS or lumbar disc herniation. Immunohistochemistry for LOX-1 was performed using human LF
samples. The correlation between the cross-sectional area
(CSA) of LF under axial magnetic resonance imaging andthe total counts of LOX-1-positive cells was examined.
In in vitro study, we treated the cells with inflammatory
cytokines tumor necrosis factor (TNF)-α and interleukin(IL)-1β, oxidized LDL, and simvastatin. The mRNA expressions of LOX-1 and LF hypertrophy markers including type I collagen, type III collagen, and COX-2 wereassessed by real-time reverse transcriptase polymerase
chain reaction and the protein expression of LOX-1 byimmunocytochemistry. Phosphorylation of MAPKs (p38
mitogen-activated protein kinase) and nuclear factor-κB(NF-κb) was evaluated by Western blot after treatment
with oxidized LDL and simvastatin.
Results: The protein expression of LOX-1 and the CSA of
LF were positively correlated (r=0.37). The in-vitro TNF-α

Asian Spine Journal
and IL-1β treatments increased both mRNA and protein
expression of LOX-1 in LF cells. Conversely, simvastatin
treatment significantly neutralized the oxidized LDLmediated induction of the mRNA expressions of type
I collagen, type III collagen, and COX-2. Western blot
analysis showed that oxidized LDL activated the signalingof p38, Erk (extracellular signal-regulated kinase), JNK (cjun-N-terminal kinase), and NF-κb in LF cells, and thatsimvastatin treatment reduced the phosphorylation of allthese signaling.
Conclusions: We found a link between the oxidized LDL/
LOX-1 system and LF hypertrophy. Our results indicatethat the oxidized LDL/LOX-1 system may be a potential
therapeutic target for LSS.

PS-FP-13-12

Laser Resonance Frequency Analysis of
Pedicle Screw Stability: A Cadaveric Model
Bone Study
Daisuke Nakashima1, Katsuhiro Mikami2,
Shunsuke Kikuchi1, Toshiyuki Kitamura3,
Noboru Hasegawa3, Masaharu Nishikino3,
Morio Matsumoto1, Masaya Nakamura1, Takeo Nagura1,4
1

Department of Orthopaedic Surgery, Keio University School of Medicine,Tokyo, Japan
2
Faculty of Biology‐Oriented Science and Technology, Kindai University,
Higashiosaka, Japan
3
The National Institutes for Quantum and Radiological Science andTechnology, Quantum Beam Science Research Directorate, Kansai Photon
Science Institute, Chiba, Japan
4
Department of Clinical Biomechanics, Keio University School of Medicine,Tokyo, Japan

Purpose: Insertion torque and pull-out force are generally
used for evaluating pedicle screw stability at the laboratorylevel. However, these techniques are bone-invasive, and itis therefore, impossible to perform them more than once
after the pedicle screw has been inserted. We developed
a novel device to perform resonance frequency analysis(RFA) using a laser that is non-invasive, non-contact, andrepeatable technique for applications in the field of spinal
surgery. Here, we examined the relationships among threetest forces, namely, insertion torque, pull-out force, andLaser-RFA using model bones and cadaveric vertebrae.
Methods: Six different types of model bones (30 materials) and nine fresh non-frozen cadaveric human lumbar

S163

vertebrae (18 pedicles) were tested. We inserted the Associa pedicle screw (Kyocera Medical Corp., Osaka, Japan).
Three kinds of test forces, namely, peak torque as a part ofinsertion torque (Nm), pull-out force (N), and Laser- RFA(Hz) were performed. Pearson’s correlation coefficients (R)were used to evaluate relationships among the three test
forces in model bones and vertebrae.
Results: Model bones: There was a strong correlation between insertion torque and pull-out strength (R=0.901,
p<0.001) as previously reported. Laser-RFA showed strong
correlations with insertion torque and pull-out strength
using (both: R=0.931, p<0.01). Vertebrae: There was astrong correlation between insertion torque and pull-out
strength (R=0.823, p<0.01). Laser RFA showed strong
correlation with insertion torque (R=0.811, p<0.001) andmoderate correlation with pull-out strength (R=0.644,
p<0.01). Overall, the results for vertebrae tended to havelower correlation coefficients than those for model bone.
Conclusions: In dentistry, unlike insertion torque andpull-out strength, which reflect axial force, RFA reflects
stability when the implant is tilted sideways, which ismore similar to the multidirectional stress applied to
implants in vivo. We previously indicated that the RFA
tends to have a similar tendency even with the pedicle
screw using the dental RFA device. There is a possibility that results of Laser-RFA indicate the correct pedicle
screw fixation strength than insertion torque and pullout strength as the same as dental RFA system. For thecontinued development of pedicle screws, a quantitative,
repeatable, and non-invasive method to measure implantstability is necessary. Our findings lend a strong support
for the hypothesis that Laser-RFA is a suitable method forevaluating pedicle screw stability.

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Asian Spine J 2021;15(Supplement 1):S1-S177

PS-FP-13-14

Do Academic Pediatric Orthopaedists Who
Treat Spine Receive Increased Industry
Funding?
Alice Chu1, Sean Haimowitz1, Michael Fields1,
Lynn Ann Forrester2, Leah Gonzalez3, Lauren Seo3,
Caixia Zhao1, Neil Kaushal1, Folorunsho Edobor-Osula1
1

Division of Pediatric Orthopaedics, Department of Orthopaedic Surgery,
Rutgers-New Jersey Medical School, Newark, NJ, USA
2
Department of Orthopedics, Columbia University Medical Center, New
York, NY, USA
3
Department of Orthopedic Surgery, New York University School of
Medicine, New York, NY, USA

Purpose: There is disparity within the orthopedic subspecialties with regards to industry funding in the UnitedStates, with spine surgeons being one of the highest compensated recipients, and pediatric orthopaedists being thelowest. The purpose of this study was to investigate theimpact of clinical interest in spine on industry funding
to pediatric orthopedic providers. We hypothesized thata clinical interest in the treatment of spine deformities
would be associated with increased industry funding forpediatric orthopaedists. To provide appropriate perspective, this study also aimed to determine whether gender,
academic rank, region, and scholarly productivity wereassociated with industry payments to pediatric orthopedic
surgeons.
Methods: This study was a retrospective cross-sectional
analysis of industry payments to academic pediatric orthopedic surgeons in 2016. Academic orthopedic surgery
departments in the United States were identified using
Fellowship and Residency Electronic Database. We collected publicly available data on specialty training, gender,
faculty rank, region, and years since residency from institutional websites. Surgeons who completed at least one
fellowship in pediatric orthopedics were included. Clinical interest in spine for pediatric orthopaedists was determined by information on faculty profile pages. Scholarly
productivity data was obtained as H-index from Scopus,
a major abstract and citation database for peer-reviewed
studies. Industry funding data from 2016 was collectedfrom the Centers for Medicare and Medicaid Services
Open Payments Database.
Results: Of the 339 pediatric orthopaedists included in
our analysis, 76% (257) were men and 24% (82) were

women. Approximately half (54%) declared an expertisein spine. Clinical interest in spine was not associated withincreased industry payments: $178 (interquartile range[IQR], $66–$1,500) vs. $132 (IQR, $35–$1,442); p=0.17.
Overall, men received more industry funding than
women (median: $162 [IQR, $63–$2,056) vs. $111 [IQR,$23–$591]; p=0.02). Surgeons with higher H-index earned
more from industry (r=0.14, p=0.01).
Conclusions: Despite spine surgeons being among thehighest industry earners within the entire field of orthopedics, clinical involvement with spine was not associatedwith increased industry payments to academic pediatricorthopaedists. In the studied group, higher H-index andmale gender were associated with increased industry payments, while region, years in practice, and academic rank
were not.

PS-FP-13-15

The Efficacy of C5a Receptor Antagonist
for Human iPSC-Derived Neural Stem/
Progenitor Cell Transplantation in the Injured
Spinal Cord of Mice
Reo Shibata1,2, Narihito Nagoshi1, Keita Kajikawa1,
Yasuhiro Kamata1, Shuhei Ito1, Mahamad Khazaei3,
Michael G. Fehlings3, Morio Matsumoto1,
Hideyuki Okano2, Masaya Nakamura1
1

Department of Orthopedic Surgery, Keio University, Tokyo, Japan
Department of Physiology, Keio University, Tokyo, Japan
3
Division of Genetics and Development, Krembil Research Institute,
University Health Network, Toronto, ON, Canada
2

Purpose: We previously reported the efficacy of humaniPS derived neural stem/progenitor cell (hiPSC-NS/PC)
transplantation for spinal cord injury (SCI) in the subacute phase. However, this procedure is not effective in
the acute phase due to the inflammatory response occurring immediately after SCI, which weakens transplanted
cell survival and differentiation. C5a, which is one of thecomplement components, is a powerful chemoattractant
and recruits inflammatory cells through binding C5a receptor. Therefore, the objective of this study is to suppress
the inflammatory response immediately after SCI using
C5a receptor antagonist (C5aRA) as an immunosuppressant, thus improving the efficacy of hiPSC-NS/PC transplantation for SCI in acute phase.

Asian Spine Journal
Methods: We used immunodeficient SCID-Beige micethat lack lymphocytes and natural killer cells. First, toevaluate the influence of C5aRA on the inflammatory response post-SCI, we induced a thoracic spinal contusion
injury in mice. We quantified inflammatory cytokines
and inflammatory cells in injured spinal cord tissues
using quantitative polymerase chain reaction (qPCR),
RNA sequence, and flow-cytometry. Next, we divided
the SCI mice into four groups (phosphate-buffered saline[PBS] only, C5aRA only, PBS+transplantation [PBS+TP],
C5aRA+transplantation [C5aRA+TP]). Immediately after
SCI, C5aRA or PBS was administrated once a day for 4
consecutive days, and then, 5.0×105 hiPSC-NS/PCs weretransplanted into the lesion epicenter on day 4. We evaluated cell survival rate by Bioluminescent Imaging (BLI),
hindlimb motor function by Basso Mouse Scale score, andthe differentiation profile of the graft hiPSC-NS/PCs byimmunohistochemistry.
Results: C5aRA administration significantly reduced interleukin (IL)-1b, IL-6, and tumor necrosis factor-α at 12hours and macrophages at 4 days after SCI (p<0.05). RNA
sequence revealed that C5a inhibition reduced several
inflammatory cytokines at 12 hours and 1day after SCI
and apoptotic marker at 4days after SCI. The C5aRA+TP
group had better functional improvement as comparedto the PBS only group (p<0.05). BLI revealed that the
C5aRA+TP group had a significantly higher cell survival
rate compared to the PBS +TP group (p<0.05). There wasno significant difference in the differentiation profiles of
the graft hiPSC-NS/PCs between C5aRA+TP group and
PBS+TP group.
Conclusions: The present study demonstrated that administration of C5aRA could suppress the inflammatory
response during the acute phase of SCI, and also improve
the survival rate of transplanted hiPSC-NS/PCs and enhance motor functional restoration. hiPSC-NS/PCs transplanted with C5aRA are a promising treatment for acutephase SCI patients.

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PS-FP-13-16

Cytokine Changes Cultured Cells Harvested
from Cervical Spine of Patients with Ossificationof the Posterior Longitudinal Ligament
Hideki Saito, Takafumi Yayama, Kanji Mori,
Kosuke Kumagai, Masahiro KItagawa, Shinji Imai
Department of Orthopedic Surgery, Shiga University of Medical Science,Otsu, Japan

Purpose: Ossification of the posterior longitudinal ligament (OPLL) progresses gradually for a prolonged period,
which may lead to serious spinal cord complications.
During OPLL, the regulation of cell differentiation at theossification front plays an indispensable role. Additionally,cytokines production may be affected during the maturation of cells, such as chondroblast or osteoblast. This study
is designed to investigate the cytokine networks in OPLL,
using immunohistochemical examination and suspension array cytokine analysis. In particular, we focused oninterleukin (IL)-6 and examined the correlation with theexpression of transcription factors.
Methods: Ligamentous samples were harvested from 12
patients with OPLL who underwent spinal surgery (sevenmen and five women; six segmental types; six continuous types; mean age, 54.8 years at time of surgery; range,
42–92 years). Tissue sections were used for in-vitro culture to obtain primary cells through migration methods.
Cytokine profile of cultured cells, deriving from OPLL
patients, was compared with the cytokine profile of sevensubjects from non-OPLL patients using the suspension array system to measure the concentration of 27 inflammatory cytokines or growth factors. The sections were also
examined by immunohistochemistry for the expressionof these cytokines. IL-6 was added (0, 10, 50, 100 ng/mL)
to the cultured cells prepared by the migration method,the expression of Sox9, Runx2, and SIRT1 in the cells wasobserved by immunoblot analysis.
Results: Suspension array evaluation of the cultured cells
showed that the expression of IL-6, basic fibroblast growth
factor, and RANTES (regulated on activation, normal T
cell expressed and secreted) were significant in patientswith OPLL. In continuous type OPLL, the expression of
IL-6 and RANTES were especially high. In OPLL groups,
Sox9 and SIRT1 decreased and Runx2 increased due tothe addition of IL-6. In the control group, no significant

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change in expression was observed. Immunohistochemistry showed that Sox9 and SIRT1 expressions were positive
for chondrocytes and mesenchymal cells on the ossification front, and Runx2 was strongly positive for mesenchymal cells near the ossification front.
Conclusions: SIRT1 is a factor involved in biological processes such as cell lifespan and aging. It has been pointed
out that the expression of SIRT1 is suppressed by inflammatory cytokines, and the decrease in SIRT1 expression
due to the addition of IL-6 makes osteoblast differentiation more significant than chondrocyte differentiationfrom mesenchymal stem cells. It was thought that thiswould promote ossification.

PS-FP-13-17

Automatic Recognition of Whole Spine
Sagittal Alignment and Curvature Analysis
through a Deep Learning Technique
Yu-Jui Huang1, Yu-Cheng Yeh1, Chi-Hung Weng2,
Chen-Ju Fu3, Chao-Yuan Yeh2, Tsung-Ting Tsai1
1

Department of Orthopaedic Surgery, Spine Division, Bone and Joint
Research Center, Chang Gung Memorial Hospital and Chang Gung
University College of Medicine, Taoyuan, Taiwan
2aetherAI Co. Ltd., Taipei, Taiwan
3
Department of Medical Imaging and Intervention, Chang Gung Memorial
Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan

Purpose: Various spinal shapes and positional parameters
have been proposed to describe human sagittal balance.
Deep learning (DL) technique enables fast and accurate
assessment of spinal parameters. Recent advances of
spline sagittal curvature analysis for whole spine alignment, such as inflection points (IP) and apices, and theirrelationships between deformity correction prognosis had
been recognized. The aim of this study was to develop a
fully automatic system of whole spine sagittal alignment
recognition and curvature analysis through DL technique.
Methods: From January 2018 to April 2020, a total of 1,500
consecutive whole spine lateral images were reviewed and24 vertebral landmarks were annotated using costumed
Matlab program. A two-staged Cascade Pyramid Network(CPN) DL model was trained for anatomical landmark
detection, which enabling automatic recognition of allvertebral centers and their linear connections. The shapeof sagittal alignment and Cobb angles represent lordotic

or kyphotic proportion of spine were approached by Bspline method. Inflection points of between kyphoticlordotic junctions, and the apices of thoracic and lumbar
area were generated by differentiation calculus. The reliability between DL model and traditional human annotations were assessed by intraclass correlation coefficient(ICC).
Results: A total of 300 images were randomly selected as
testing data for model performance evaluation. The median localization errors from C2 to L5 of the CPN model
were ranged from 1.81 to 3.07 mm. The whole spinalalignment curvature was automatically depicted in different categories of spine disease such as scoliosis, degeneration, vertebral fracture. The mean predicted C-T and T-L
inflection point levels was located at C7±1 and L2±1. The
mean predicted thoracic and lumbar apex levels was located at T8±2 and L4±1. Compared with the ground truth
values, the predictions of CPN model showed excellent reliability in C-T, T-L inflection point and thoracic, lumbar
apex (ICC=0.895, 0.952, 0.890, and 0.975, respectively).
The ICC of cobb angle represented the kyphotic and lordotic portion between two inflection points were 0.859
and 0.927, which also showed excellent reliability.
Conclusions: The deep learning framework was able toprecisely predicted the position of vertebral centers, inflection points, apices and Cobb angles of the whole spinealignment with excellent accuracy. Future applications ofsurgical planning, database analysis, regular postoperative
follow-up, and population-based screening could be explored for validations of the system and improve clinicalefficiency.

PS-FP-13-19

Prognosis of Iatrogenic Spinal Cord Injury
at a Major Rehabilitation Center in United
Kingdom
Aashish Babanrao Ghodke, Navin Kumar
Midlands Spinal Cord Injury & Rehabilitation Centre, Oswestry, UK

Purpose: The incidence of iatrogenic injury is more thanwhat is quoted in the literature. Aim of our study was todetermine the incidence and common etiologies responsible for iatrogenic spinal cord injury (SCI) in patients
admitted at a dedicated spinal cord rehabilitation center.

Asian Spine JournalThis study aimed to study the prognosis of these patientsin terms of neurological and functional outcomes for aperiod of 2 years.
Methods: This study analyzed al the SCI admissions torehabilitation center over a duration of 4 years. These patients were followed at 6 weeks, 1 year, and at 2 years post
the injury. The patients were assessed as per the American
Spinal Cord Injury Association Scale for the neurologicaloutcomes and as per the Spinal Cord Independence Measure version for the functional outcomes.
Results: Out of 528 admissions, 42 patients were reported
to have iatrogenic SCI. The most leading cause of deterioration in our study was ischemic insult to the cord after
vascular surgeries like aneurysm, arteriovenous (AV)malformation, aortic dissection, and AV fistula repair(eight cases), the 2nd most common cause was after an
inadequate decompression (six cases), 3rd was mechanical pressure due to postoperative hematoma or a pseudomenindocele (five cases), 4th being implant related(three cases), and indirect cord manipulation as a result of
deformity correction in scoliosis/kyphosis patients (threecases). One out of the three patients did show intraoperative signal loss on neuro-monitoring. Two patients had
episodes of intraoperative and postoperative hypotension.
Sixteen cases in our series didn’t have an identifiable cause
but a couple of cases showed postoperative high signals on
T2 weighted magnetic resonance imaging scan, suggestiveof a vascular insult as a result of sudden decompression
and one patient deteriorated after postoperative infection;
therefore, an infective embolus could well be attributed asa probable cause. At 2-year follow-up after rehabilitation,
17 patients started mobilizing, 22 were wheelchair boundand could not walk, and three died. Twenty-two patientswere intact before they underwent the surgery and 16 patients were adolescent idiopathic scoliosis D preoperative.
The Spinal Cord Independence Measure scores for thesepatients improved from a mean of 30.10 (standard deviation [SD]=19.56) to 59.09 (SD=23.62) at 2 years.
Conclusions: The incidence of iatrogenic SCI is higher
than it is reported. There is a dire need of epidemiologicalstudies to quantify these injuries and follow them up to
see the prognosis of these patients in terms of neurological and functional outcomes.

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PS-FP-13-23

Accelerated Recovery Protocol Following
Posterior Spinal Fusion for Adolescent Idiopathic
Scoliosis Leading to Early Hospital Discharge
Teddy Suratos Fabila1, Angela Siok Hoong Yeo1,
Mini Abraham2, Narayani D/O Jayakrishnan2,
Shin Huey Ng3, Kevin Boon Leong Lim4
1

Department of Paediatric Anaesthesia, Division of Surgery, KK Women’sand Children’s Hospital, Singapore
2
Division of Nursing, KK Women's and Children’s Hospital, Singapore
3
Physiotherapy Department, KK Women's and Children’s Hospital,
Singapore4
Department of Orthopaedics, Division of Surgery, KK Women’s andChildren’s Hospital, Singapore

Purpose: To determine if a standardized Accelerated Recovery Protocol (ARP) consisting of multimodal analgesia, early mobility exercises, and early patient feeding inadolescent idiopathic scoliosis (AIS) patients undergoing
posterior spinal fusion (PSF) will lead to better pain control, lesser opioid usage, and related side effects, and early
hospital discharge.
Methods: All subjects with AIS who underwent posterior
spinal fusion surgery by a single attending surgeon were
included in the project. Phase 1 is a retrospective cohort
study from January 2015 to December 2016. We divided
the cohort into two: baseline group (B) patients prescribedwith patient-controlled analgesia (PCA) morphine andphase 1 group (P1) patients prescribed with PCA morphine plus ketamine 1:1 concentration. Our physiotherapists provided once-a-day exercise sessions on weekdays
but not weekends and holidays. Surgeons started soft dieton postoperative day (POD) 3. Phase 2 is a prospective
interventional audit that followed ARP from June 2017 toJuly 2020. Pain treatment included PCA Morphine plus
Ketamine 1:1 concentration. Paracetamol, Ibuprofen or
Etoricoxib, and Diazepam or Orphenadrine were given
to all groups, while Clonidine was only prescribed forP2 patients. All parental pain treatments in this project
were converted to oral when a patient tolerated a soft diet.
Our physiotherapists increased visits to twice a day during weekdays and once on weekends and holidays. Soft
diet initiated on POD 1, then full meals on POD 2. We
conducted a post implementation (PI) audit from August2020 to January 2021. The primary outcomes were mean
daily pain scores and mean daily opioid usage (intravenous

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Morphine equivalent mg/kg/day). Secondary outcomes
included hospital stay and frequency of opioid-relatedside effects requiring intervention.
Results: The number of subjects per group was; 15 in B,
16 in P1, 25 in P2, and 11 in PI. The frequency of subjects who reported pain scores of more than 6 in groups
P1, P2, and PI was significantly less when compared togroup B on POD1 (p=0.004), POD2 (p=0.022), and POD3
(p=0.000). Morphine usage was significantly lower in
P1, P2, and PI than B (POD1: p=0.041, POD2: p=0.000,
POD3: p=0.002). The PI subjects were discharged home
38.4% earlier. Fewer patients in groups P1, P2, and PI,
reported nausea and vomiting requiring additional ondansetron (30% less). Nil reported readmission due touncontrolled pain.
Conclusions: The standardized ARP implementation leads
to lower pain scores, lesser opioid usage, reduced frequency of nausea and vomiting, and early hospital discharge.

PS-FP-13-24

How Much Experience Is Required to Acquire
the Skills for Spinal Surgery? Results of a Surveyof Spine Surgeons
Ryunosuke Fukushi1, Mitsunori Yoshimoto1,
Naohisa Miyakoshi2, Daisuke Kudo2, Yoichi Shimada2,
Toshihiko Yamashita1
1Department of Orthopaedic Surgery, Sapporo Medical University School of
Medicine, Sapporo, Japan2
Department of Orthopaedic Surgery, Akita University School, Akita, Japan

Purpose: Surgical experience is essential to master theskills required in spinal surgery. Practical training on actual patients is indispensable when learning proper techniques. However, no report has evaluated the number ofspinal operations that a surgeon needs to acquire the skills
required for each surgical technique before being able toperform the procedure independently.
Methods: This study was aimed at conducting an e-mailsurvey. We asked 70 spine surgeons about 12 types ofspinal surgery, namely upper cervical surgery, anteriorcervical fusion, posterior cervical decompression/fusion,anterior lumbar fusion, posterior lumbar decompression,endoscopic posterior lumbar decompression, posterior
lumbar decompression and fixation, lumbar disk hernia-

tion, endoscopic lumbar disk herniation, spinal tumor
resection, spinal kyphosis surgery, and percutaneous vertebroplasty. For each procedure, they were asked to identify whether they could (A) not perform the procedure atall, (B) perform the procedure with the help of a senior
surgeon, or (C) perform the procedure independently. If
the participants chose A or B for any of the procedures,
they were asked how many cases they felt they neededto acquire the necessary skills to perform the procedures
independently. Those who chose C for any procedure
were asked to state the number of cases they actually
performed to acquire the required skills. The participantsalso responded to questions on 10 items regarding surgical training. They were asked to rate the usefulness of thesurgical training methods on a 5-point scale.
Results: In total, 55 surgeons completed the survey. The
participants who reported an inability to perform the following surgeries (group A) required significantly morecases than those who reported complete independence(group C): upper cervical spine surgery (A/C: 19.3/7.3),
anterior cervical decompression/fusion (28.8/6.7), posterior cervical decompression/fusion (27.3/9.5), lumbar disk
herniation (26.7/12.6), endoscopic lumbar disk herniation(24.2/10.2), spinal tumor resection (37.2/6.5), and spinal
kyphosis surgery (32.3/10.3). More than 80% of the participants responded that operations with assistance from asenior surgeon; lectures and self- education with surgery
manuals, articles, and textbooks; and surgical videos wereeffective training resources. By contrast, >50% of the participants responded that surgical training on animals wasineffective.
Conclusions: We conducted a survey of 55 spine surgeons
to determine the number of cases required to achieveautonomy for 12 different spinal surgeries. Surgeons who
could not yet independently perform a specific surgery
needed more cases than those who could perform theprocedures independently.

Asian Spine Journal
PS-FP-13-25

Novel In Vivo Imaging System of Grafted
Human Induced Pluripotent Cells-Derived
Neuron Activity after Spinal Cord Injury
Kentaro Ago, Narihito Nagoshi, Morio Matsumoto,
Hideyuki Okano, Masaya Nakamura
Department of Orthopaedic Surgery, Keio University, Tokyo, Japan

Purpose: Spinal cord injury (SCI) is a devastating andincurable disease. NS/PCs (neural stem/progenitor cells)
transplantation is one of the most promising therapies
for SCI. NS/PCs integrate into spinal injury lesion andenhance motor function recovery. The grafted cells canmainly differentiate into neurons, but only a little has beenreported if grafted neurons actually show action potential
in vivo. The aim of this project is to establish a novel invivo imaging system of neural activity of grafted neurons,
and to reveal the connectivity between host circuit neurons projecting to the lesion and grafted neurons.
Methods: First, dorsal column lesions to the C4 spinal
cord and subacute grafting on immunodeficient mice were
performed. We transplanted NS/PCs derived from humaninduced pluripotent cells (iPSCs) that has AkaBLI systemexpressed understream immediate early gene (IEGs; anindirect marker of neuronal activity) promotor. AkaBLI
system is a bioluminescence in vivo imaging system that
produces bright emissions so that we can detect the weak
expression of IEGs. Second, we also introduced excitatory
designer receptors exclusively activated by designer drugs(DREADD) transgene, hM3Dq, into corticospinal neurons injecting AAV vector into host sensorimotor cortex
at six weeks after transplantation. Three to four weeks
after corticospinal tract labeling when viral vector permits
efficient anterograde access to the C4 lesion, we assessed
the genuine effect of corticospinal neurons’ activation ongrafted cells measuring their photoncounts. We can activate DREADD system administering clozapine-N-oxide(CNO) that is the prototypical DREADD activator.
Results: Because of corticospinal neurons’ activation
caused by excitatory DREADD system in vivo, the photoncount of grafted cells with CNO administration increased indirectly, reached 1.5 times as high as that without CNO on average. As the positive control, grafted cells’
direct activation caused by excitatory DREADD system
led to more than 3 times higher photoncounts of grafted

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cells in another mouse. Immunohistochemistry showed
the luminescence and Venus fluorescence that makes
fusional protein with AkaLuc were related to positive correlation, that is consistent with in vitro data.
Conclusions: Grafted neurons were indirectly activated after corticospinal neurons’ activation via DREADD system.
That implies that synaptic connectivity between host corticospinal neurons and grafted neurons had been formedin vivo. We confirmed this active synaptic connection occurred in free moving animals applying this novel in vivo
imaging system. In the future, we can assess the effect of all
kinds of synaptic organizers, or even cell-type associateddifferences regarding graft-host synaptic differentiation.

PS-FP-13-27

Comparison of the Global Sagittal Alignment
and Surgical Outcomes for Osteoporotic
Vertebral Body Fracture Between Lower
Lumbar and Thoracolumbar Area
Tomoya Matsuo, Koki Uno, Kohei Kawakita,
Teppei Suzuki, Masaaki Ito
Kobe Medical Center, Kobe, Japan

Purpose: There are few papers evaluated sagittal alignmentof the patients who underwent surgery for the osteoporotic vertebral fracture (OVF) because of the difficulty instanding due to late-onset paralysis. The purpose of thisstudy is to evaluate the global spinal parameters and tocompare the surgical outcomes of lower lumbar fractureswith that of the thoracolumbar fracture.
Methods: Retrospective study at a single center. Thirtythree patients of the 123 patients who underwent surgery
for OVF with a minimum follow-up of 2 years after surgery were identified. These patients were divided into twogroups. Fractures in the 10th to 2nd lumbar vertebrae
were defined as the thoracolumbar group (group TL: 27
cases), and fractures in the 3rd to 5th lumbar vertebrae
were defined as the lower lumbar group (group LL: six
cases). The average number of fixed intervertebral discs(group TL, LL) was 5.9±0.4 and 7.8±2.8 (p=0.20). The
numbers of patients who underwent posterior fusion
down to the pelvis are 4 (14.8%) in the group TL and 3(50%) in group LL, respectively (p=0.06).
Results: Preoperative spinal parameters (group TL, LL)S170

Asian Spine J 2021;15(Supplement 1):S1-S177

are sagittal vertical axis (SVA): 81.8±10.4 mm, 144.2±32.9mm (p<0.05), pelvic tilt: 27.7°±2.1°, 44.4°±3.5° (p<0.05),
pelvic incidence: 49.7°±1.8, 64°±2.2° (p<0.05), lumbar
lordosis: 26.1°±3.9°, 7.6°±4° (p<0.05). The amount of SVAchange from postoperative to final observation (group TL,
LL) was 28.7±9.7 mm, 90±13.2 mm (p<0.05), and the increase in local kyphosis after surgery (group TL, LL) was
4.9°±1.4°, 14.4°±8.0° (p<0.05). By the time of the final observation, proximal junctional kyphosis incidence (group
TL, LL) was 25.9%, 50% (p=0.25). The reoperation rate
(group TL, LL) was 7.4%, 16.7% (p=0.48). The Japanese
Orthopaedic Association score (group TL, LL) was evaluated on a scale of 15 points, preoperatively 7.7±0.4, 6.6±1.4
points (p=0.30), postoperatively 10.6±0.4, 11.0±0.8 points(p=0.68).
Conclusions: There were not significant differences in radiographical and clinical outcomes between two groups. Ingroup LL, the longer fixation than previous reported may
cause less complication rate compared with group TL.

PS-FP-13-28

Comparison of the Stability and Osseointegrationof Different Intravertebral Fixators
Jui-Yang Hsieh1,2,3, Yi-You Huang1, Jyh-Horng Wang2,
Po-Quang Chen2

fixation at the compressed thoracolumbar segments. Fourpigs were implanted at each of the six lumbar segmentswith the following five type of constructs: (1) solid (VPG0), (2) perforated (VPG-1), (3) hollow (VPG-2), (4) threedimensional printed (VPG-3), and (5) intravertebral
expandable pillar (I-VEP). All subject pigs received X-ray,computed tomography (CT), micro-CT and histomorphometry evaluation.
Results: All implants were implanted securely without
any occurrence of major complications. Decent levels ofalignment of the implants were shown in the series of Xray and CT inspections. High levels of bone ingrowth andbone ongrowth are observed in the results of the microCT and histomorphometric evaluations. The average results of bone volume/tissue volume ratio (BV/TV), bone
surface/tissue volume ratio (BS/TV), trabecular bone
thickness (TBT), and trabecular bone number (TBN)
were highest in group VGP-2 while the values of trabecular bone separation (TBS) were the lowest. However, no
statistically significant differences were found between thevarious VGP groups and commercialized I-VEP group interms of BV/TV, BS/TV, TBT, TBS, and TBN results.
Conclusions: Similar levels of osteointegration were observed to different VPG construct each with different rates
of hollow/solid ratio in microstructure analysis in in-vivo
porcine models. All the different VPG constructs showedsimilar levels of stability and implant-bone contact incomparison with the commercially available I-VEP.

1

Department of Biomedical Engineering, National Taiwan University, Taipei,
Taiwan2
Department of Orthopedic Surgery, National Taiwan University Hospital,
Taipei, Taiwan
3
Department of Orthopedic Surgery, National Taiwan University Hospital
Jinshan Branch, New Taipei, Taiwan

Study Design: Clinical animal studies.
Purpose: To determine the safety and utility of a novel
modular spine block (VeroPlaGo, VPG) before its use in
human subjects.
Overview of Literature: It is an intuitive notion that reducing the use of bone cement while maintaining the correction of the vertebral compression fracture would contribute to a decrease in the occurrence of the above-mentioned
complications. The theoretical advantages of modular
spinal blocks (VeroPlaGo, VPG) include its ability to support and maintain vertebral height, without incurring thecomplications related to the use of bone cement.
Methods: VPG was designed to provide intravertebral

PS-FP-13-29

Do Ovariectomy and Calcium-Restricted Diets
Create Osteoporosis in Porcine Model?
Jui-Yang Hsieh1,2,3, Yi-You Huang1, Yao-Horng Wang4,5,
Jyh-Horng Wang2, Po-Quang Chen2
1

Department of Biomedical Engineering, National Taiwan University, Taipei,
Taiwan2
Department of Orthopedic Surgery, National Taiwan University Hospital,
Taipei, Taiwan
3
Department of Orthopedic Surgery, National Taiwan University Hospital
Jinshan Branch, New Taipei, Taiwan
4Department of Nursing, Yuanpei University of Medical Technology,
Hsinchu, Taiwan
5Department of Veterinary Medicine, National Chung Hsing University,
Taichung, Taiwan

Study Design: Clinical animal studies.

Asian Spine Journal
Purpose: To evaluate the mid-term changes in bone mineral density (BMD) with calcium-restricted and ovariectomized miniature porcine models as a large animal modelin osteoporosis.
Overview of Literature: Compared to canines, dairy goatsor sheep, the vertebral anatomies of pigs resemble that ofhumans the most. The physiological characteristics of pigs
are very similar to those of humans. Pigs are relatively
easy to obtain at a reasonable price, which is why they arenormally preferred over other types of animal models.
Methods: Four 6-month-old (T0), female ovariectomized
miniature pigs that had been fed low calcium diets wereenrolled in this study. The body weight of each pig was recorded. Ovariectomy were operated on each pig at the ageof 1 year and 3 months (T1). The pigs were fed a normal
diet prior to the ovariectomy, but switched to a diet withrestricted calcium content afterwards. Each of the pigs
received dual-energy X-ray absorptiometry once before
ovariectomy, and once every three months (T2, T3, T4)
after the ovariectomy to evaluate the changes in BMD. All
the BMD readings were checked 3 times.
Results: The body weight of all four subject pigs increased
significantly during this study (p<0.05). The initial changes in both the BMC and BMD levels (T1/T2) were foundto be statistically insignificant (p=0.325 and p=0.137,
respectively). However, upon comparison of later BMC
and BMD changes (T3/T4, T1/T3 and T1/T4), statisticallysignificant elevations were found (p<0.05 for all threecomparisons). Between the time stages T2 and T2, BMC
showed a statistical increase (p<0.05) while the BMD didnot (p>0.05).
Conclusions: Ovariectomy and calcium-restricted diets
are ineffective in achieving an osteoporotic porcine model
based on BMD assessments. BMD levels of the subject
pigs continued to rise until the point at which body
growth had stopped.

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PS-FP-13-30

Consideration of Cryopreservation Solutions
and Methods of Nucleus Pulposus Cells for
Industrialization
Kosuke Sako1, Daiske Sakai1, Yoshihiko Nakamura2,
Erika Matsushita2, Takayuki Warita2, Natsumi Horikita2,
Masato Sato1, Masahiko Watanabe1
1Department of Orthopaedic Surgery, Tokai University School of Medicine,Tokyo, Japan
2
Research Center for Regenerative Medicine, Tokai University School of
Medicine, Tokyo, Japan

Purpose: We previously reported that nucleus pulposus
cells (NPC) showed no significant difference in their viability, differentiation ability, and extracellular matrix
production before or after cell cryopreservation. This suggested that activated NPC could be used as a commercial,mass-produced, off-the-shelf regenerative therapeutic
product, but still, there is a large difference between theclinical application and the laboratory-based reports. For
example, the time required for cryopreservation is rarely
taken into consideration, and the cytotoxicity of animal
serum and dimethyl sulfoxide (DMSO) may present safetyconcerns for clinical applications. Therefore, we investigated the effects of the cryopreservation solutions within
real-world mass- production time circumstances.
Methods: Primary human NPC were collected fromyoung disc hernia patients (n=5; mean age, 20.4 years)
after consent, and isolated according to previous report.
The samples were kept at room temperature or on ice for0.5, 1, 2, 3, 4, and 5 hours, within one of six cryopreservation solutions (i.e., CELLBANKER 1 [CB1], STEMCELLBANKER GMP grade [SCB], STEM-CELLBANKERDMSO Free GMP grade [SCBD-Free], CryoStor CS10
[CS10], CP-1, and Pro Freeze-CDM [PF]). After thesedefined incubation times, cell viability was either directly
analyzed or analyzed following cryo-storage at -80°C for 1day. Additionally, thawed cells were cultured for 5-7 days
and analyzed on their proliferation- and Tie2-positivity
rate.
Results: Comparing the CELLBANKER series, only CB1
showed satisfactory cell viability after 3 hours (CB1:mean, 95.8±3.7%; SCB: mean, 64.6±2.1%; SCBD-Free:mean, 51.3±2.2%; p=0.021). Most cryopreservation solutions resulted in rapid cell viability loss over time, while
CB1 and CS10 showed limited viability loss. If the incuba-

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Asian Spine J 2021;15(Supplement 1):S1-S177

tion time was limited to 3 hours, both solutions resulted
in 90% or more cell viability after thawing. Also, CB1
and CS10 incubated cells showed higher proliferation
rates (CB1: 93.3, CS10: 43.3-fold increase) after thawing,compared to other cryopreservation solutions (SCB: 24.0,
SCBD-Free: 16.0, CP-1: 29.2, PF: 28.3-fold increase). Furthermore, CS10 had a highest Tie2 positive rate of 12.6%
after culturing for 5 days after thawing, compared to othercryopreservation solutions (CB1: 6.6%, SCB: 5.1%, SCBDFree: 5.1%, CP-1: 4.3%, PF: 2.5%).
Conclusions: CB1 had the highest cell viability and cellproliferation rate after thawing, although CS10 showedcomparable performance and higher Tie2 positive rates. It
proved difficult to maintain cell viability without DMSO
for human NPC; however, animal serum could be removed by using CS10.

PS-FP-13-31

Clinical Efficacy of Ultrasound Guided
Bilateral Erector Spinae Block for Single
Level Lumbar Fusion Surgery: A Prospective,
Randomized, Case-Control Study
Chandhan Murugan1, Vipin Goel2, Madhan Mohan2,
Ajoy Shetty1, Rajasekaran Shanmuganathan1
1

Department of Spine Surgery, Ganga Medical Centre and Hospitals Pvt.
Ltd., Coimbatore, India
2
Department of Anesthesia, Ganga Medical Centre and Hospitals Pvt. Ltd.,
Coimbatore, India

Purpose: Post-operative experience plays a vital role inrecovery of a patient and does not depend on the typeand quality of the surgical procedure alone. Non-opioid
therapies have become part of the multimodal analgesic
regimen for better pain control and reduced opioid relatedside effects. Most recently evolved among these are theregional anesthetic techniques, such as the thoracolumbar interfascial plane (TLIP) block and the erector spinae(ESP) block. The aim of this study is to assess the efficacy
of ultrasound guided (US) ESP block for postoperative
analgesia after a single level lumbar spine fusion surgery
compared with conventional (opioid-based) multimodal
postoperative analgesia.
Methods: This is a prospective randomized controlled
double blinded study including 100 patients requiring
single level lumbar fusion surgery. Patients were randomly

allocated into block (multimodal analgesia with US-ESP)
and control groups (only multimodal analgesia). Patientswere assessed intra- operatively for blood loss, durationof surgery, opioid usage and amount of muscle relaxants
used. Postoperatively the parameters studied included
Numeric Pain Intensity (NRS) score, modified observer’s
alertness/sedation score (MOASS), satisfaction score, andtotal amount of opioids consumed in the initial 24 hours.
Continuous variables were analyzed using Student t-test
and categorical variables were analyzed using either thechi-square test or Fisher’s exact test. A p-value <0.05 wasconsidered as statistically significant.
Results: Total opioid consumption (TOC) in the 24 hours
from the start of surgery was significantly lower in theblock group than the control group (105.0±15.15 mcg
vs. 158.00±23.38 mcg, p<0.001). The total muscle relaxant consumption during surgery was also significantly
less in the block group as compared to the control group(51.90±3.17 vs. 57.70±5.90, p<0.0001). The intra-operative
blood loss was significantly less (p<0.0001) in the blockgroup (303.00±86.55 mL) as compared to the control
group (437.00±116.85 mL). Compared to the block group,
the control group’s pain score (NRS) was significantly
higher in the first 48 hours following surgery. The MOASSscore was significantly less in control group compared toblock group in the immediate postoperative period (0–4
hours). The satisfaction score was significantly higher
in the block group as compared to the control group(9.52±0.65 vs. 8.22±0.79, p<0.0001).
Conclusions: Ultrasound guided ESP block for single level
lumbar fusion surgery is an excellent component of multimodal analgesia for alleviating the perioperative pain.

Asian Spine Journal
PS-FP-13-32

The Effect of Anti-Receptor Activator of
Nuclear Factor-κB Ligand Monoclonal
Antibody on Spinal Fusion in a Mouse Spinal
Fusion Model
Soji Tani1,2,3, Koji Ishikawa1,2,3, Yoshifumi Kudo1,
Akira Matsuoka1, Hiroshi Maruyama1, Ryo Yamamura1,
Chiakara Hayakawa1, Koki Tsuchiya1, Takashi Nagai1,
Nobuhiro Sakai3,4, Mayumi Tsuji2,3, Yuji Kiuchi2,3,
Tomoaki Toyone1, Katsunori Inagaki1
1

Department of Orthopaedic Surgery, Showa University School of Medicine,Tokyo, Japan2
Department of Pharmacology, School of Medicine, Showa University, Tokyo,
Japan
3
Pharmacology Research Center, Showa University, Tokyo, Japan
4
Department of Pharmacology, School of Dentistry, Showa University, Tokyo,
Japan

Purpose: Spinal fusion surgery is commonly used to treat
unstable spinal condition. The purpose of fusion surgery
is to gain a solid union and bony fusion. However, bone
fusion sometimes delays or fails and pseudarthrosis is welldescribed complication of fusion surgery. Anti-receptor
activator of nuclear factor-κB ligand (RANKL) monoclonal antibody is widely used for osteoporosis patient.
However, the effect of anti-RANKL monoclonal antibody
in spinal surgery is unknown. Therefor, we investigatedwhether anti-RANKL monoclonal antibody acceleratebone fusion in a mouse spinal fusion model.
Methods: A total of 24 male, 8-week-old, C57BL/6J mice
underwent posterior spinal arthrodesis surgery using collagen sponge. The animals were randomly assigned to oneof the following groups: saline containing collagen and saline injection (group 1); BMP-2 containing collagen (containing 1.0 µg in each sponge) and saline injection (group2); saline containing collagen and anti-mouse RANKLneutralizing monoclonal antibody injection (OYC1: 5 mg/kg) (group 3); BMP-2 containing collagen and OYC-1
injection (group 4). OYC1 or saline were injected the day
after surgery. The quantitative evaluation of bone fusion
was performed by direct palpation, computed tomography (CT), and micro-CT.
Results: Newly formed bone were visualized in treatedwith BMP-2 (group 2 and group 4), whereas no bone formation were observed in treated without BMP-2. Bonefusion was accelerated in group 4 compared to group 2(group 2: 4 weeks, group 4: 3 weeks). Furthermore, in mi-

S173

cro-CT analysis, group 4 showed the superior results than
the group 3 (volumetric bone mineral density [151.5 mg/
cm3 vs. 488.2 mg/cm3], BV/TV [16.8% vs. 71.8%], trabecular thickness [9.4 μm vs. 55.5 μm], trabecular separation[51.6 μm vs. 19.7 μm]; group 3 vs. group 4, all p<0.05).
Conclusions: Postoperative administration of anti-RANKL
monoclinal antibody significantly increase fusion rateand improve the quality of newly formed bone. Our result
suggests that anti-RANKL monoclonal antibody might bea good option in management of spinal fusion surgery.

PS-FP-13-34

Efficacy of Human Induced Pluripotent
Stem Cell-Derived-Gliogenic NS/PCs forTransplantation in the Chronic Phase of Spinal
Cord Injury
Yasuhiro Kamata1,2, Mitsuhiro Inoue2,3, Miho Isoda2,3,
Munehisa Shinozaki2, Morio Matsumoto1,
Hideyuki Okano2, Masaya Nakamura1, Jun Kohyama2,
Narihito Nagoshi1
1Department of Orthopaedic Surgery, Keio University, Tokyo, Japan
Department of Physiology, Keio University, Tokyo, Japan
3
Regenerative & Cellular Medicine Kobe Center, Sumitomo Dainippon
Pharma Co. Ltd., Osaka, Japan
2

Purpose: One of the main pathologies in spinal cord
injury (SCI) is demyelination of neuronal axons, thus remyelination of host axons by grafting glial cell including
oligodendrocyte progenitor cells is considered as a promising strategy to restore function in damaged spinal cord.
We have reported efficient remyelination by transplanting
human induced pluripotent stem cell-derived gliogenic
NS/PCs (hiPSCs-gNS/PCs) for SCI mice in the subacutephase. However, demographically, most patients with SCI
are in the chronic phase, and therapeutic development
would be imperative for the patients. Therefore, the purpose of the present study was to investigate the efficacy ofthe hiPSCs-gNS/PCs for the rodent model of SCI in thechronic phase.
Methods: Contusive SCI was induced at the Th10 levelin immunodeficiency rat, and the hiPSCs-gNS/PCs weretransplanted into 2 points around lesion epicenter 42 days
after the injury. An equal volume of phosphate bufferedsaline was injected for the control group. Motor functionof injured rat was assessed by the Basso, Beattie, Bresna-

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han Locomotor Rating score, and DigiGait analysis. Histological analyses were performed to examine the survival
and differentiation of the grafted cells.
Results: Histological analyses revealed that the transplanted cells well survived and migrated far into the host spinal cord without any tumor formation. The transplanted
cells differentiated into three neural lineages including
neurons, astrocytes and oligodendrocytes. The area withregenerative fibers (pGAP43+ area) in the transplantedgroup were significantly larger than that in the control
group. The active remyelination on damaged axon in injured spinal cord was observed in the transplanted groupby immunoelectron microscopy. Importantly, hindlimb
motor function named BBB score was significantly improved in the transplanted group. Rotarod tests revealed
a significant motor functional improvement in the transplanted group at 12 weeks after transplantation.
Conclusions: The past studies of cell transplantation in thechronic phase reported the limited efficacy. This study has
proven that the transplanted cells contributed to the improvement of motor function with robust remyelination
for the demyelinated axon and the regenerative fibers.
Our laboratory is planning clinical application for spinal
cord injury in the future, and the result of this study is expected to be a promising cell source for treating SCI evenin the chronic phase.

PS-FP-13-36

A Retrospective Audit of Effectiveness andReliability of Telemedicine Consultations inPatients with Spinal Ailments
Rohit Akshay Kavishwar, Ajoy Prasad Shetty,
S. Rajasekaran
Ganga Medical Center, Spine Surgery Department, Coimbatore, India

Purpose: In view of the ongoing pandemic, telemedicine
has been increasingly adopted worldwide. This retrospective cohort study was planned to evaluate the effectivenessof telemedicine for patients with spine ailments; and to assess the satisfaction rates and concerns of spine surgeons
and patients regarding telemedicine consultations in Indian scenario.
Methods: Telemedicine appointments for spine patientswere conducted through “Zoom-Healthcare” online plat-form between April and November 2020 in a tertiarycare spine center. Questionnaires (including nine and fivequestions, respectively) were filled by patients and doctors after their consultations. The questionnaire included
questions on overall satisfaction, time consumption, easeof setting-up appointment, ease of communication, influence on decision making and patient preference.
Results: Overall, 70.1%, 23.6%, and 6.3% of patients replied that they were “very satisfied”, “satisfied”, and dissatisfied” with their telemedicine appointments. Amongpost-operative follow-up patients, 69%, 30.2%, and 0.8%
expressed that they were “very satisfied”, “satisfied”, anddissatisfied”, respectively with telemedicine. At the endof the session, 88.5% of patients opined that they would
still prefer a telemedicine appointment for the completed
consultation; and 93.4% were happy to use telemedicine
for future visits. The doctor’s responses were “very satisfied” or “satisfied” on 96.5% of occasions overall. The
doctors required approximately 24.1 minutes for conducting a telemedicine appointment. Three major concerns
for doctors included difficulty in procuring good-quality
magnetic resonance imaging (17%), problems with connectivity (14.6%), and difficulty in eliciting certain physical findings (13.2%).
Conclusions: Telemedicine is an effective alternative to inperson visits for the assessment of patients with spine ailments. A majority of the post-operative follow-up patientswere satisfied with their remote consultations. In specificsituations, these remote visits may need to be complemented by in-person visits for thorough evaluation.

Asian Spine Journal
PS-FP-14-1

Intradiscal and Epidural Platelet-Rich Plasma
Injection for the Treatment of Chronic
Discogenic Low Back Pain
En Song1, Ji Zheng Li2, Yan Lin Li1, You Qing Huang3,
En Bin Wang4, Fan Bing Li2, Xiao Feng Yuan5,
Xue Song Chen6, Yao Yu Xiang1, Xian Guang Yang1
1Department of Sports Medicine, The First Affiliated Hospital of Kunming
Medical University, Kunming, China
2
Department of Orthopedics, First Clinical Medical College of Yunnan
University of Traditional Chinese Medicine, Kunming, China
3
Department of Pain, The Second Affiliated Hospital of Kunming Medical
University, Kunming, China
4
Department of Orthopedics, Baoshan Hospital of Traditional Chinese
Medicine, Shanghai, China
5
Department of Orthopedics, The First People’s Hospital of Kunming, China
6
Department of Pain, The Fourth People’s Hospital of Kunming, Kunming,
China

Purpose: Platelet-rich plasma (PRP) has been found to beeffective for a variety of musculoskeletal conditions. The
treatment of discogenic pain with PRP is under investigation. This study to explore the clinical effects and safety of
PRP in treating chronic discogenic low back pain.
Methods: The clinical data of 21 patients (22 disc) from
June 2017 to December 2018 were diagnosed with discogenic low back pain by clinical means, imaging. Inclusion
criteria for this study included chronic low back pain
without leg pain for more than 3 months; one or more
lumbar discs degeneration, as indicated via magnetic
resonance imaging; and at least one symptomatic disc,confirmed using standardized provocative discography
and exclusion of other structures included discitis and tumor. Patients underwent treatment of intradiscal and epidural injection of PRP at one or multiple levels. Outcome
measures included the use of a Visual Analog Scale (VAS)
and Oswestry Disability Index (ODI) score. Patients were
followed up at intervals of preoperative, postoperative 1month, 3 months, and last follow-up.
Results: Data were analyzed from 21 patients (11 men and
10 women; mean age, 37.8 years). Following treatment,no patient experienced adverse events or significant narrowing of disc height. The mean preoperative low backpain VAS scores decreased from 6.81±0.83 to 1.44±0.58
at 1 months after surgery, 1.38±0.51 at 3 months after surgery, 1.02±0.58 at final follow-up after surgery. The mean
preoperative ODI scores decreased from 75.2±13.3 toS175

33.4±10.8 at 1 months after surgery, 25.2±3.2 at 3 months
after surgery, 20.2±1.2 at final follow-up after surgery(p<0.01).
Conclusions: This study demonstrated that intradiscal
and epidural injection of autologous PRP in patients withlow back pain was safe, with no adverse events observed
during follow-up. Intradiscal and epidural PRP injection
is a safe and a possibly effective treatment for discogenic
low back pain. Randomized placebo-controlled trials areneeded to further evaluate the efficacy of this treatment.

PS-FP-14-2

One-Year Clinical Result of Condoliase for
Lumbar Disc Hernia
Atsushi Yoshioka, Kenichiro Tanaka, Yudo Hachiya
Hachiya Orthopaedic Hospital, Nagoya, Japan

Purpose: Condoliase is a minimally invasive treatment oflumbar disc hernia (LDH), started in August 2018 and isbecoming popular in Japan. However only short-term results have been reported, and there have been no reports
on clinical results for more than 1 year. The purpose ofthis study was to evaluate 1-year clinical results of condoliase for lumbar disc hernia.
Methods: A total of 18 patients with LDH (12 males, six
females; mean age, 31.5 years) who underwent injectionof condoliase between August 2018 and September 2020
were followed for 1 year after administration. All patients
had a subligamentous type hernia at L3/4, L4/5, L5/6, or
L5/S1 verified on magnetic resonance imaging. We examined the Visual Analog Scale (VAS), complications, imaging parameters, before, and 3 weeks, 3 months, and 1 year
after administration.
Results: Condoliase improved VAS score (back pain, legpain, leg numbness) after 3 weeks administration, and significantly improved after 3 months. The mean VAS scoresat baseline and 3 months were 51 mm and 22 mm in backpain, and 72 mm and 23 mm in leg pain, and 53 mm and
16 mm in leg numbness. The improvements of symptoms
were maintained until 1 year. Condoliase did not caused
clinically important adverse events, but allergy-like symptoms (rash) were observed one patient. One patient underwent surgery because of no improvement symptoms
after administration. In the imaging analysis, a significant

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Asian Spine J 2021;15(Supplement 1):S1-S177

decrease in disc height ware observed after 3 weeks, but
after that no significant decrease after 3 months and 1
year. Disc height decreased from 9 to 7 mm 3 weeks afteradministration, and 6.5 mm and 6.0 mm in 3 months and1 year.
Conclusions: In this report, the effectiveness of condoliase
at 3 months after administration could be maintainedeven after 1 year. The decrease in disc height, which isconcern with condoliase, was observed in the early stage
up to 3 months after administration, but no significant
progression was observed up to 1 year after that. Condoliase is a safe and effective treatment for LDH. Further
studies needed to confirm effectiveness of condoliase forrecurrent LDH after surgery.

PS-FP-14-3

The Effectiveness of Chemonucleolysis with
Condoliase for Treatment of Painful Lumbar
Disc Herniation
Eijiro Okada1, Satoshi Suzuki1, Satoshi Nori1,
Osahiko Tsuji1, Narihito Nagoshi1, Mitsuru Yagi1,
Nobuyuki Fujita2, Masaya Nakamura1, Morio Matsumoto1,
Kota Watanabe1
1Department of Orthopaedic Surgery, Keio University School of Medicine,Tokyo, Japan2
Department of Orthopaedic Surgery, Fujita Health University, Toyoake,Japan

Purpose: Chemonucleolysis with condoliase, which degrades chondroitin sulfate, could be a new, minimallyinvasive therapeutic option for patients with lumbar discherniation (LDH). The purpose of this study was to analyze prognostic factors for clinical outcomes in LDH patients subjected to chemonucleolysis with condoliase.
Methods: Inclusion criteria for this procedure were (1)18–70 years of age; (2) unilateral leg pain and positive
straight leg raise (SLR) (<70°) or femoral nerve stretching
test; (3) subligamentous extrusion verified on magnetic
resonance imaging; (4) neurological symptoms consistent
with a compressed nerve root on magnetic resonanceimaging images; and (5) minimum 6 months of followup. In total, 82 patients (55 men, 27 women; mean age,47.2±15.5 years; mean follow-up, 9.1±3.0 months) who
underwent chemonucleolysis with condoliase for painful
LDH were included. An improvement of 50% or more in

the Visual Analog Scale (VAS) of leg pain was classified as
effective.
Results: Seventy patients (85.4%) were classified into theeffective (E) group and 12 patients (14.6%) into the lesseffective (L) group. Surgical treatment was required infour patients. No severe adverse complications were reported; 41.3% of the patients developed disc degenerationof Pfirrmann grade 1 or more at the injected disc level.
Univariate analysis revealed that young age (p=0.036),
without history of epidural or nerve root block (p=0.024),
and injection into the central portion of the intervertebral
disc (p=0.014) were significantly associated with clinicaleffectiveness. A logistic regression analysis revealed that
injection into the central portion of the intervertebral
disc (p=0.049; odds ratio, 4.913; 95% confidence interval,
1.006–26.204) was significantly associated with clinical effectiveness.
Conclusions: Chemonucleolysis with condoliase is a safeand effective treatment for painful LDH; 85.4% of thepatients showed improvement after the treatment without
severe adverse events. To obtain the best outcome, condoliase should be injected into the center of the intervertebral disc.

PS-FP-14-4

Transforaminal Full Endoscopic Discectomy
and Thermal Annuloplasty for High Signal
Intensity Zone Radiculopathy
Kazuta Yamashita, Fumitake Tezuka, Masatoshi Morimoto,Kazuya Kishima, Kiyoshi Yagi, Koichi Sairyo
Department of Orthopedics, Tokushima University, Tokushima, Japan

Purpose: High signal intensity zone (HIZ), presented
in 1992, is a high signal change on the posterior site ofintervertebral disc in T2 weighted magnetic resonanceimaging. It is said that HIZ means the fibrous tears after
degeneration of the disc and the secondary inflammation
causes for the pain source of the chronic low back pain.
We sometimes see the patients who suffer radicular pain
and numbness of their buttock and leg without the compression to the nerve root. We named this new pathology
as “HIZ radiculopathy” and have performed transforaminal full endoscopic spine surgery (TF-FESS) under local
anesthesia if the conservative treatment was not effective.

Asian Spine Journal
Methods: In this retrospective study, 21 patients (male12, female nine; average age, 48 years old) underwent TFFESS due to HIZ radiculopathy in our hospital. Intraoperative findings, surgical time, blood loss, radicular pain
(MacNab’s criteria), low back pain (VAS), and the period
for return to job were investigated using medical record.
Results: Average surgical time was 64 minutes; blood loss
was uncountable in all cases. MacNab’s criteria accepted
excellent 18, good 2, and fair 1. The average perioperative

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VAS was improved from 8 to 2. There is no complication
intra- and postoperatively in all cases and the average period for return to job was 11 days. In some cases, vessels
and bleeding were seen endoscopically at anulus fibrosus.
Conclusions: It may occur the radicular pain with the
inflammation around the nerve root even if the compression to the nerve root is not severe. TF-FESS might begood indication and effective for HIZ radiculopathy if thepatients would like to return to job earlier.