bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thoracic microendoscopic discectomy
Authors: Perez-Cruet Mick J. , Kim Bong-Soo , Sandhu Faheem , Samartzis Dino , Fessler Richard G. 
Published: May 2009

Object.Various approaches exist for the treatment of thoracic disc herniation. Anterior approaches facilitate ventral exposure but place the intrathoracic contents at risk. Posterolateral approaches require extensive muscle dissection that adds to the risk of postoperative morbidity. The authors have developed a novel posterolateral, minimally invasive thoracic microendoscopic discectomy (TMED) technique that provides an approach to the thoracic spine which is associated with less morbidity.Methods.Seven patients 23 to 54 years old with nine disc herniations underwent TMED. All lesions were soft lateral or midline thoracic disc herniations. Under fluoroscopic guidance with the patient positioned prone, the authors used a muscle dilation approach and the procedure was performed with endoscopic visualization through a tubular retractor.Based on a modified Prolo Scale, five patients experienced excellent results, one good, and one fair. No case required conversion to an open procedure. The mean operative time was 1.7 hours per level, and estimated blood loss was 111 ml per level. Hospital stays were short, and no complications occurred.Conclusions.The TMED is safe, effective, and provides a minimally invasive posterolateral alternative for treatment of thoracic disc herniation without the morbidity associated with traditional approaches.
Metabolic neuroimaging of the cervical spinal cord in patients with compressive myelopathy: a high-resolution positron emission tomography study
Authors: Uchida Kenzo , Kobayashi Shigeru , Yayama Takafumi , Kokubo Yasuo , Nakajima Hideaki , Kakuyama Michiko , Sadato Norihiro , Tsuchida Tatsuro , Yonekura Yoshiharu , Baba Hisatoshi 
Published: May 2009

Object. The authors conducted a study to examine whether high-resolution [18F]fluorodeoxyglucose (FDG)—positron emission tomography (PET) could be used to visualize deterioration of cervical spinal cord function associated with various degrees of compression and to determine its potential usefulness during assessment of compressive myelopathy.
Methods. In 23 patients requiring decompressive surgery for myelopathy FDG-PET was performed. The preoperative findings of high-resolution FDG-PET were compared with the neurological scores and magnetic resonance (MR) imaging findings. The preoperative standardized uptake value (SUV) of FDG utilization rate of the cervical cord correlated with the pre- (r = 0.497, p = 0.016) and postoperative neurological scores (r = 0.595, p = 0.003), as well as with the rate of neurological improvement postoperatively (r = 0.538, p = 0.008). The FDG utilization rate did not correlate with the high signal intensity on T2-weighted MR images.
Conclusions. Analysis of these results indicates that high-resolution FDG-PET imaging provides useful qualitative and quantitative estimates of impaired metabolic activity of the compromised cervical cord that correlate closely with the severity of neurological dysfunction.
Vulnerability of the subcostal nerve to injury during bone graft harvesting from the iliac crest
Authors: Chou Dean , Storm Phillip B. , Campbell James N. 
Published: May 2009

Object. Autologous bone graft harvesting from the iliac crest remains the gold standard for fusion surgery. One disadvantage of autologous bone harvesting is the patient's enduring postoperative pain at the donor site. Nerve injury is one of the postulated mechanisms that may account for this pain. The object of this study was to determine whether the lateral cutaneous branch of the subcostal nerve is vulnerable to injury in the process of obtaining grafts from the anterior iliac crest.
Methods. Anatomical dissections were performed on 10 cadaveric specimens to ascertain the size of the T-12 subcostal nerve and its position in relation to the iliac crest.
Conclusions. The lateral cutaneous branch of the subcostal nerve may lie as close as 6 cm from the anterior superior iliac spine. This nerve is very vulnerable to injury when harvesting bone from the anterior iliac crest. Knowledge of the anatomy may decrease the risk of injury to this nerve.
The use of bone morphogenetic protein—6 gene therapy for percutaneous spinal fusion in rabbits
Authors: Laurent Jeffrey J. , Webb K. Michael , Beres Elisa J. , McGee Kevin , Li Jinzhong , van Rietbergen Bert , Helm Gregory A. 
Published: May 2009

Object.Fusion procedures in the lumbar spine have been performed in the US since 1911. Since that time, the indications and techniques for spinal fusion have evolved. Despite technical advancements, spinal fusion remains a major operation, and fusion nonunion rates of up to 35% are still reported. In this study, the authors were able to induce intertransverse process fusions in immune-competent New Zealand White rabbits by percutaneous administration of an adenoviral vector containing the bone morphogenetic protein(BMP-6)gene (Ad-BMP-6). The results represent an important step forward in finding new methods to increase the success and decrease the morbidity associated with spinal fusion.Methods.Five New Zealand White rabbits were used. Injection of the adenoviral construct was performed at multiple levels (bilaterally) in each animal while using fluoroscopic guidance. Injection consisted of either Ad-BMP-6 or Ad—β-galactosidase (β-gal) (control). Because multiple levels were injected, each animal served as an internal control. The animals underwent postinjection computerized tomography (CT) scanning at 7 and 14 weeks. After undergoing final CT scanning, the animals were killed and the spines were harvested. The fusion sites were analyzed by gross inspection, histopathological methods, and micro—CT studies.Conclusions.The results of this study show that an anatomically precise fusion can be accomplished by percutaneous administration of gene therapy. The next step in these studies will be extension of the technique to nonhuman primates and eventually to human clinical studies.
Single-unit artificial intervertebral disc
Authors: Alberts Russell , Patil Arun-Angelo , Zhou Dongxue 
Published: May 2009

Object. The authors describe a new type of artificial disc called a single-unit artificial disc (SUAD). It is a single-unit disc without components, and there is no fixation system with which to maintain it in the disc space. It is theorized that its shape, hardness, and surface consistency, together with the compressive force exerted by the body's axial load, should be adequate to maintain the position of the disc in the disc space. In this paper the authors present their results of the kinematic tests in which the stability and integrity of the SUADs was tested.
Methods. Panorobot was used for kinematic test fixture for fatigue testing for different types of SUAD. The test was performed after placing the disc between the C-5 and C-6 vertebral bodies (VBs) obtained from a cadaver. Eight pounds of weight was placed on the top of the container housing the C-5 VB to account for the weight of the head. The robot performed the following movements: 1) flexion—extension, 4.7° each; 2) lateral left—right bending, ± 2.1°; and 3) coupled rotation, ± 3.8°. Two flat discs (FDs) of 85 durometer (D), four 30D FD, two recess-edged discs (REDs) of 85D, and four custom-designed discs (CDDs) (custom molded to the disc space) of 30D were tested.
None of the discs showed cracks or breakage at the end of the study. After 1 million cycles of excursions all 85D and 30D FD, and both 85D REDs showed weight loss. The 30D CDDs showed minimal weight gain at 1 million cycles. One of the CDDs, tested up to 5 million cycles, did lose weight at 5 million cycles.
One 85D FD was extruded after 0.2 million cycles and one 85D RED rotated within the disc space. All other discs maintained their position in the disc space. Dimensional changes were minimal. Scanning electron microscopy of particles collected from one 30D CDD sample after 1 million cycles showed rough irregular granular particles 1 to 600 µm in diameter.
Conclusions. These findings show that a 30D SUAD can maintain its position in the disc space without any anchoring device. Furthermore, at 1 million cycles of testing of 30 D SUAD, FDs did as well as the CDDs. This may be because softer discs mold to changes in dimension of the disc space. In addition the softer discs tend to wear less than the harder ones. Further fatigue study of 10 million cycles is needed to determine long-term efficacy, and the effects of wear on particles surrounding the joints need to be studied.
Biomechanical testing of anterior and posterior thoracolumbar instrumentation in the cadaveric spine
Authors: Eichholz Kurt M. , Hitchon Patrick W. , From Aaron , Rubenbauer Paige , Nakamura Satoshi , Lim Tae Hong , Torner James 
Published: May 2009

Object. Thoracolumbar burst fractures frequently require surgical intervention. Although the use of either anterior or posterior instrumentation has advantages and disadvantages, there have been few studies in which these two approaches have been compared biomechanically.
Methods. Ten human cadaveric spines were subjected to subtotal L-3 corpectomy. In five spines placement of L-3 wooden strut grafts with lateral L2–4 dual rod and screw instrumentation was performed. Five other spines underwent L1–5 pedicle screw fixation. The spines were fatigued between steps of the experiment. The spines were load tested with pure moments of 1.5, 3, 4.5, and 6 Nm in the intact state and after placement of instrumentation in six degrees of freedom (flexion, extension, right and left lateral bending, and right and left axial rotation).
In axial rotation posterior instrumentation significantly increased spinal rigidity compared with that of the intact state, whereas anterior instrumentation did not. Combined anterior—posterior instrumentation did not significantly increase the rigidity of the spine when compared with anterior or posterior instrumentation alone. Posterior instrumentation alone provided a greater reduction in angular rotation compared with anterior instrumentation alone in all degrees of freedom; however, statistical significance was achieved only in extension at 6 Nm.
Conclusions. The increased rigidity provided by pedicle screw instrumentation compared with the intact state or with anterior instrumentation is due to the longer construct spanning five levels and the three-column engagement of the pedicle screws. The decision to use anterior or posterior instrumentation should be based on the clinical necessity of canal decompression and correction of angulation.
Mechanical properties and function of the spinal pia mater
Authors: Ozawa Hiroshi , Matsumoto Takeo , Ohashi Toshiro , Sato Masaaki , Kokubun Shoichi 
Published: May 2009

Object. The pia mater has received little attention regarding its function in the deformation of the spinal cord under compression. In this study the mechanical properties and function of the spinal pia mater were investigated using three methods.
Methods. Spinal cord segments were excised from rabbits. The elastic modulus of the pia mater was measured by performing a tensile test using specimens with the pia mater intact and ones with the pia mater stripped off. The stiffness of the spinal cord was examined by performing a compression test with specimens containing an intact pia mater and ones with a pia mater that was incised at both sides. The cross-sectional area and circumference of the spinal cord were measured on axial views of magnetic resonance images in patients with cervical disc herniations before and after surgery.
The pia mater had an elastic modulus of 2300 kPa, which was 460 times higher than that of spinal cord parenchyma. By covering the parenchyma, it tripled the overall elastic modulus of the spinal cord. The pia mater increased the stiffness of the spinal cord and enhanced its shape recovery after removal of the compression. The cross-sectional area of the spinal cord increased after surgery, whereas the circumference of the spinal cord changed little.
Conclusions. The pia mater firmly covers the spinal cord and has a high elastic modulus; it therefore provides a constraint on the spinal cord surface. It prevents elongation of the circumference and produces a large strain energy that is responsible for shape restoration following decompression.
Neurological complications of lumbar artificial disc replacement and comparison of clinical results with those related to lumbar arthrodesis in the literature: results of a multicenter, prospective, randomized investigational device exemption study of Charité intervertebral disc
Authors: Geisler Fred H. , Blumenthal Scott L. , Guyer Richard D. , McAfee Paul C. , Regan John J. , Johnson J. Patrick , Mullin Bradford 
Published: May 2009

Object. Arthrodesis is the gold standard for surgical treatment of lumbar degenerative disc disease (DDD). Solid fusion, however, can cause stress and increased motion in the segments adjacent to the fused level. This may initiate and/or accelerate the adjacent-segment disease process. Artificial discs are designed to restore and maintain normal motion of the lumbar intervertebral segment. Restoring and maintaining normal motion of the segment reduces stresses and loads on adjacent level segments. A US Food and Drug Administration Investigational Device Exemptions multicentered study of the Charité artificial disc was completed. The control group consisted of individuals who underwent anterior lumbar interbody fusion involving BAK cages and iliac crest bone graft. This is the first report of Class I data in which a lumbar artificial disc is compared with lumbar fusion.
Methods. Of 304 individuals enrolled in the study, 205 were randomized to the Charité disc-treated group and 99 to the BAK fusion—treated (control) group. Neurological status was equivalent between the two groups at 6, 12, and 24 months postoperatively. The number of patients with major, minor, or other neurological complications was equivalent. There was a greater incidence of both major and minor complications in the BAK fusion group at 0 to 42 days postoperatively. Compared with data reported in the lumbar fusion literature, the Charité disc—treated patients had equivalent or better mean changes in visual analog scale and Oswestry Disability Index scores.
Conclusions. The Charité artificial disc is safe and effective for the treatment of single-level lumbar DDD, resulting in no higher incidence of neurological complications compared with BAK-assisted fusion and leading to equivalent or better outcomes compared with those obtained in the control group and those reported in the lumbar fusion literature.
Three-level and four-level anterior cervical discectomies and titanium cage—augmented fusion with and without plate fixation
Authors: Hwang Shiuh-Lin , Lin Chih-Lung , Lieu Ann-Shung , Lee Kung-Shing , Kuo Tai-Hung , Hwang Yan-Fen , Su Yu-Feng , Howng Shen-Long 
Published: May 2009

Object. Cage-assisted anterior cervical discectomy and fusion (ACDF) has proven to be a safe and effective procedure for the treatment of one- and two-level degenerative disc disease (DDD). To the authors' knowledge, clinical results after three- and four-level interbody cage—augmented ACDF have not been reported in the literature. The authors investigated the safety and effectiveness of titanium cages used in such procedures and evaluated the results in cases with or without plate fixation.
Methods. Fifty-six patients suffering from cervical DDD were divided into two groups. Group 1 included 32 patients who underwent titanium cage—assisted ACDF; Group 2 included 24 patients who underwent the same procedure, supplemented with plate fixation. The cervical DDD was confirmed by radiography and magnetic resonance imaging. The patients underwent radiographic evaluation to assess cervical lordosis, segmental height of cervical spine, the height of the foramina, and spinal stability. Neurological outcomes were assessed using the Japanese Orthopaedic Association (JOA) scores. Neck pain was graded using a 10-point visual analog scale (VAS). The follow-up period ranged from 13 to 28 months (mean 17.2 months).
In both Groups 1 and 2 significant increase (p < 0.001) was demonstrated in the JOA scores (preoperatively 10.7 ± 2.4 and 11.1 ± 2, postoperatively 13.9 ± 2.2 and 14.1 ± 2.3, respectively) and VAS pain scores (preoperatively 8.8 ± 0.9 and 8.5 ± 1, postoperatively 3.1 ± 2.1 and 2.8 ± 1.8, respectively); however, there was no significant intergroup difference. A significant increase in the cervical lordosis, foraminal height, and segmental height was observed in both groups. Good stability of cage fusion was obtained in both groups 12 months postoperatively (90.6% in Group 1 and 91.7% in Group 2); however, there were no statistically significant intergroup differences. The complication rate in Group 2 was higher than that in Group 1. The hospital length of stay in Group 1 was significantly lower than in Group 2 (p < 0.001).
Conclusions. Analysis of these findings demonstrated that titanium cage—assisted ACDF provided long-term stabilization, increased lordosis, increased segmental height, and increased foraminal height. In both groups good neurological outcomes were achieved and donor site morbidity was avoided. The lower complication rate and shorter hospital stay, however, make the cage-assisted fusion without plate fixation better than with plate fixation.
Long-term results of expansive open-door laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine
Authors: Ogawa Yuto , Toyama Yoshiaki , Chiba Kazuhiro , Matsumoto Morio , Nakamura Masaya , Takaishi Hironari , Hirabayashi Hisashi , Hirabayashi Kiyoshi 
Published: May 2009

Object. Numerous surgical procedures have been developed for treatment of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine, and these can be performed via three approaches: anterior, posterior, or combined anterior—posterior. The optimal approach in cases involving OPLL-induced cervical myelopathy, however, remains controversial. To address this issue, the authors assessed the benefits and limitations of expansive open-door laminoplasty for OPLL-related myelopathy by evaluating mid- and long-term clinical results.
Methods. Clinical results obtained in 72 patients who underwent expansive open-door laminoplasty between 1983 and 1997 and who were followed for at least 5 years were assessed using the Japanese Orthopaedic Association (JOA) scoring system. The mean preoperative JOA score was 9.2 ± 0.4; at 3 years postoperatively, the JOA score was 14.2 ± 0.3 and the recovery rate (calculated using the Hirabayashi method) was 63.1 ± 4.5%, both having reached their highest level. These favorable results were maintained up to 5 years after surgery. An increase in cervical myelopathy due to progression of the ossified ligament was observed in only two of 30 patients who could be followed for more than 10 years. Severe surgery-related complications were not observed. Preoperative JOA score, age at the time of surgery, and duration between onset of initial symptoms and surgery affected clinical results.
Conclusions. Mid-term and long-term results of expansive open-door laminoplasty were satisfactory. Considering factors that affected surgical results, early surgery is recommended for OPLL of the cervical spine.
Vertebral synovial chondromatosis
Authors: Gallia Gary L. , Weiss Nirit , Campbell James N. , McCarthy Edward F. , Tufaro Anthony P. , Gokaslan Ziya L. 
Published: May 2009

✓ Synovial chondromatosis is an uncommon disorder characterized by the formation of multiple cartilaginous nodules within the synovium, most commonly affecting large joints. Its involvement with the spine is rare; only six cases have been reported. The authors describe two patients with synovial chondromatosis involving the cervical spine. In the first case, synovial chondromatosis arose from the left C1–2 facet joint. This patient underwent a two-stage procedure including a posterior approach for tumor resection and occipitocervical fusion as well as a transmandibular circumglossal approach to the anterior craniocervical junction to complete the tumor removal. Interestingly, on histopathological examination, scattered foci of low-grade chondrosarcoma were intermixed within the synovial chondromatosis. To the authors' knowledge, this is the first report of secondary low-grade chondrosarcoma arising in vertebral synovial chondromatosis. In the second case, synovial chondromatosis involved the left C4–5 facet joint. Tumor resection and cervical fusion were performed via a posterior approach.In this report, the authors describe the clinical presentation, radiographic findings, operative details, histopathological features, and clinicoradiological follow-up data obtained in these two patients and review the literature pertaining to this rare entity.
Multimodality intraoperative monitoring during complex lumbosacral procedures: indications, techniques, and long-term follow-up review of 61 consecutive cases
Authors: Krassioukov Andrei V. , Sarjeant Roger , Arkia Homan , Fehlings Michael G. 
Published: May 2009

Object. The purpose of this study was to examine the neurological outcomes after complex lumbosacral surgery in patients undergoing multimodality neurophysiological monitoring.
Methods. Sixty-one patients were consecutively enrolled in this study. These patients underwent complex intra- and extradural lumbosacral procedures with concomitant intraoperative electromyography (EMG) monitoring of the lower-limb muscles, external anal and urethral sphincters (EAS and EUS), and lower-limb somatosensory evoked potentials (SSEPs). Long-term (minimum 2-year) clinical follow-up data were obtained in all cases.
Most patients were treated for spinal/spinal cord tumors (61%) or adult tethered cord syndrome (25%). Recordable lower-extremity SSEPs were reported in 54 patients (89%). New postoperative neurological deficits occurred in only three patients (4.9%), and remained persistent in only one patient (1.6%) at long-term follow-up examination. In only one of these cases was a significant decrease in SSEP amplitude detected. Spontaneous EMG activity was observed in the lower-extremity muscles and/or EAS and EUS in 51 cases (84%). Intraoperatively, EMG demonstrated activity only in the EUS in 5% of patients and only in the EAS in 28%. In seven patients (11%) spontaneous intraoperative EMG activity was observed in both the EAS and the EUS; however, in only three of these cases was EMG activity recorded in both sphincters simultaneously. In addition to spontaneously recorded EMG activity, electrically evoked EMG activity was also used as an intraoperative adjunct. A bipolar stimulating electrode was used to identify functional neural tissue before undertaking microsurgical dissection in 58 individuals (95%). In the majority of these patients, evoked EMG activity occurred either in one (33%) or in two muscles (9%) simultaneously. The presence of electrically evoked EMG activity in structures encountered during microdissection altered the plan of treatment in 24 cases (42%).
Conclusions. The authors conclude that the combined SSEP and EMG monitoring of lower-limb muscles, EAS, and EUS is a practical and reliable method for obtaining optimal electrophysiological feedback during complex neurosurgical procedures involving the conus medullaris and cauda equina. Analysis of the results indicates that these intraoperative adjunctive modalities positively influence decision making with regard to microsurgery and reduce the risk of perioperative neurological complications. Validation of the clinical value of these approaches, however, will require further assessment in a larger prospective cohort of patients.