Utilization of Erector Spinae Plane Blocks in a Multimodal Analgesic Pathway for Instrumentation and Fusion of Adolescent Idiopathic Scoliosis: A Feasibility Study
Phase: NA
Conditions: Pain, Postoperative, Opioid Use, Recruitment
Sponsor: Hospital for Special Surgery, New York

 
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Utilization of Erector Spinae Plane Blocks in a 
Multimodal Analgesic Pathway for Instrumentation 
and Fusion of Adolescent Idiopathic Scoliosis: A 
Feasibility Study  
 
 
FUNDER: 
Department of Anesthesiology 
PROTOCOL NO.: 
2019-2131 
VERSION & DATE: 
1/28/2022 
 
This document contains the confidential information of the Hospital for Special Surgery.  It is provided to you and your company’s personnel for 
review.  Your acceptance of this document constitutes an agreement that you will not disclose the information contained herein to others without 
the prior written consent of the Hospital for Special Surgery.  No other use or reproduction is authorized by Hospital for Special Surgery, nor does 
the Hospital for Special Surgery assume any responsibility for unauthorized use of this protocol. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
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TABLE OF CONTENTS 
 
TABLE OF CONTENTS ............................................ 2 
PROTOCOL SYNOPSIS ........................................... 3 
1.0 
INTRODUCTION ............................................. 5 
2.0 
OBJECTIVE(S) OF CLINICAL STUDY .......... 7 
3.0 
STUDY HYPOTHESES .................................. 8 
4.0 
STUDY DESIGN ............................................. 8 
4.1 
Endpoints ....................................................................................................................... 8 
4.1.1 
Primary Endpoint ...................................................................................................... 8 
4.1.2 
Secondary Endpoints ................................................................................................ 8 
4.2 
Study Sites ..................................................................................................................... 9 
5.0 
STUDY POPULATION ................................... 9 
5.1 
Number of Subjects ........................................................................................................ 9 
5.2 
Inclusion Criteria............................................................................................................. 9 
5.3 
Exclusion Criteria ........................................................................................................... 9 
6.0 
PROCEDURES ............................................... 9 
6.1 
Intraoperative Protocol ................................................................................................... 9 
6.2 
Postoperative Protocol ................................................................................................. 10 
6.3 
Data Collection ............................................................................................................. 11 
7.0 
STATISTICAL ANALYSIS ............................ 12 
8.0 
ADVERSE EVENT ASSESSMENT .............. 13 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
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PROTOCOL SYNOPSIS 
Protocol Title: 
Utilization of Erector Spinae Plane Blocks in a Multimodal 
Analgesic Pathway for Instrumentation and Fusion of 
Adolescent Idiopathic Scoliosis: A Feasibility Study 
Protocol Number: 
2019_2131 
Protocol Date: 
1/28/2022 
Sponsor: 
Department of Anesthesiology 
Principal Investigator: 
Jordan Ruby, MD 
Objective: 
This study will investigate the feasibility and efficacy of utilizing 
preoperative erector spinae plane blocks (ESPB) to decrease 
opioid needs/consumption and to decrease numeric rating scale 
(NRS) pain scores in pediatric patients undergoing spinal fusion 
for adolescent idiopathic scoliosis (AIS). 
Study Design: 
Prospective, randomized feasibility study 
Enrollment: 
24 
Subject Criteria: 
 
1. Patients undergoing multilevel posterior spinal 
instrumentation and fusion 
2. Patients between the ages of 10 years old to 19 years old 
3. Undergoing surgery for correction of AIS 
4. Patients under the care of participating surgeons: Drs 
Widmann and Blanco 
5. English Speakers 
Data Collection: 
Sources: EPIC, Medical Records, and Patient Reported. 
Variables: DOB, Race, ASA Class, Gender, Ethnicity, NRS pain 
scores at rest and with movement, Name, Cumulative opioid 
consumption morphine equivalents, ORSDS, Number of 
patients/parents agreeing to ESPB, Workflow issues in 
performing block: Time to perform, incidence of surgeon request 
to not perform, ability to perform bilateral blocks, Blinding 
assessment  (Bang’s Blinding Index), Cobb angle/spine 
curvature, length of hospital stay, Patient/parent satisfaction, 
Intraoperative variable: surgeon, anesthesiologist, surgical 
duration (time from incision-to-procedure end), anesthetic 
duration (time from induction-to-extubation), blood loss, total 
fluid administration  
Statistical Analysis: 
• 
Primary outcome will be presented as number and rate 
of patients who received ESPB successfully and 
completed all assessment 

 
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• 
This is a feasibility study so power and sample size 
calculations are not appropriate. Classically feasibility 
studies use a sample size of approximately 12 subjects 
per group (Julious, 2005).  The primary outcome will be 
descriptive, and presented as number of patients/parents 
approached: number of patients/parents enrolling in the 
study. 
• 
Secondary outcomes for safety and efficacy comparison 
will be presented primarily in a descriptive way between 
2 groups, including incidence of complications, NRS pain 
scores measured at multiple time points, time to 1st 
opioid use, incidence of opioid related side effects, and 
patient satisfaction. Continuous outcome will be 
presented as mean +/- standard deviation (opioid 
consumption, time to first opioid, NRS scores, 
patient/parent satisfaction). If results are skewed, data 
will be presented as medians (1st and 3rd quartiles). 
Normality of distribution will be determined via Shapiro-
Wilk testing, where significance of >0.05 indicates 
normally distributed data. Categorical variables 
(incidence of complications, incidence of opioid related 
side effects) will be presented as counts and 
percentages. The balance of baseline patient 
characteristics will be compared between 2 groups using 
standardized difference. 
• 
Alpha level: N/A 
• 
Beta or power level: N/A 
 
 
 

 
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1.0 INTRODUCTION 
 
 
Idiopathic scoliosis is the most common type of scoliosis (70% of all cases) with a 
prevalence of curves greater than 30 degrees to be approximately 0.2% to 0.3%. Surgical 
correction for idiopathic scoliosis is often indicated when the spine curvature is greater than 
45-50 degrees as measured by Cobb's method or if there is coexisting cardiopulmonary 
compromise. Curves necessitating surgical correction are particularly skewed toward 
females with a ratio of approximately 10:1.  
 
Inherent to surgical correction is a significant amount of morbidity to pediatric 
patients including postoperative acute pain. Practitioners have utilized a number of 
analgesic techniques to treat acute postoperative pain including intravenous patient 
controlled analgesia (PCA), intrathecal opioids, epidural catheters, wound catheters, and 
multimodal analgesia. However, many of these techniques have either limited evidence, 
inconclusive results regarding their efficacy, or barriers to use (such as changes in 
neurological function) that limit their utilization postoperatively. Nevertheless, any technique 
that utilizes opioids subjects an already at risk patient (young, low BMI, females) population 
for further nausea/vomiting, which could delay recovery, prolong hospitalizations, and 
decrease patient/parent satisfaction. To date, there only exists a single case report using 
ESPB for PSF in pediatric patients. Furthermore, the patients in this report were 21 and 22 
years old. Other reports of this technique in pediatrics have been limited to surgeries of the 
abdomen and thorax. Given the overall absence of evidence to support ESPB for pediatric 
spine surgery, this study is proposed to determine the feasibility and efficacy of bilateral 
ESPB on postoperative pain, opioid consumption, and patient satisfaction within a 
comprehensive enhanced recovery pathway (ERP) for complex spine surgery.  
 
Canale ST, Beaty JH. Campbell’s Operative Orthopaedics. 13th ed. Philadelphia, PA: 
Elsevier Mosby; 2017:1897–2120.  
Chin KJ et al. Opioid‐sparing multimodal analgesia with bilateral bi‐level erector spinae 
plane blocks in scoliosis surgery: a case report of two patients European Spine Journal 
https://doi.org/10.1007/s00586-019-06133-8  
Seki et al. Postoperative pain management in patients undergoing posterior spinal fusion for 
idiopathic scoliosis: a narrative review. Scoliosis and spinal disorders. 2018. 13:17. 
 
 
 
The ESPB was first described as a regional anesthetic technique in 2016 (Foreo) as 
a modality to block both the ventral and dorsal rami of the thoracic spinal nerves. Since its 
initial account, there have been hundreds of case reports (Almeida 2019; Chin 2019), many 
case series (Melvin 2018; Singh 2018) and, some retrospective cohort studies (Ueshima 
2019) in adult regional anesthesia that have highlighted its application to spine surgery. 
Each concludes a significant opioid-sparing capacity and improved NRS pain scores in 
patients who receive ESPB for a variety of spine surgery procedures.  
 
Within pediatric anesthesia, there have been significantly fewer reports using the 
ESPB for postoperative analgesia. Most reports suggest the utility of the ESPB for analgesia 

 
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of the anterior spinal rami in cardiac, thoracic, and abdominal surgery (Wong 2018, Patel 
2019, Hernandez 2018,) There exists only one recent case report of bilateral ESPB in two 
patients undergoing PSF for idiopathic scoliosis as a multimodal analgesic strategy for these 
patients. Given only this single case report, there is a dearth of evidence for utilization of this 
regional anesthetic technique in this patient population. Furthermore, this case is limited in 
suggesting the feasibility and efficacy of the technique given it was only reported on two 
patients.  
 
Almeida CR, Oliveira AR, Cunha P. Continuous bilateral erector spine plane block at T8 for 
extensive spine fusion surgery: Case report. Pain Pract 2019; Feb 13. doi: 
10.1111/papr.12774  
Canale ST, Beaty JH. Campbell’s Operative Orthopaedics. 13th ed. Philadelphia, PA: 
Elsevier Mosby; 2017:1897–2120.  
Chin KJ et al. Opioid‐sparing multimodal analgesia with bilateral bi‐level erector spinae 
plane blocks in scoliosis surgery: a case report of two patients European Spine Journal 
https://doi.org/10.1007/s00586-019-06133-8  
Chin KJ, Lewis S. Opioid-free analgesia for posterior spinal fusion surgery using erector 
spinae plane (ESP) blocks in a multimodal anesthetic regimen. Spine (Phila Pa 1976) 
2019;44(6):E379-383. Forero M, Adhikary SD, Lopez H, Tsui C, Chin KJ. The erector spinae 
plane block: A novel analgesic technique in thoracic neuropathic pain. Reg Anesth Pain Med 
2016;41():621-7.  
Hernandez, MA et al. Erector spinae plane block for inguinal hernia repair in preterm infants. 
Paediatr Anaesth. 2018 Mar;28(3):298-299.  
Melvin JP, Schrot RJ, Chu GM, Chin KJ. Low thoracic erector spinae pane block for 
perioperative analgesia in lumbosacral spine surgery: a case series. Can J Anaesth 
2018;65(9):1057-1065.  
Patel, N et al. Erector Spinae Plane Catheter for Postoperative Analgesia After Thoracotomy 
in a Pediatric Patient: A Case Report. A A Pract. 2019 May 1;12(9):299-301.  
Singh S, Chaudhary NK. Bilateral ultrasound guided erector spinae plane block for 
postoperative pain management in lumbar spine surgery: A case series. J Neurosurg 
Anesthesiol. 2018; Jun 29. doi: 10.1097/ANA.0000000000000518.  
Singh S, Choudhary NK, Lalin D, Verma VK. Bilateral ultrasound-guided erector spinae 
plane block for postoperative analgesia in lumbar spine surgery: A randomized control trial. 
J Neurosurg Anesthesiol. 2019; doi: 10.1097/ANA.0000000000000603.  
Tsui BCH, Fonesca A, Munshey F, McFadyen G, Caruso TJ. The erector spinae plane 
(ESP) block: A pooled review of 242 cases. J Clin Anesth 2019;53:29-34.  
Ueshima H, Inagaki M, Toyone T, Otake H. Efficacy of the erector spinae plane block for 
lumbar spinal surgery: A retrospective study. Asian Spine J 2019;13(2):254-257.  
Yayik AM, Cesur S, Ozturk F, Ahiskalioglu A, et al. Postoperative analgesic efficacy of the 
ultrasound-guided erector spinae plane block in patients undergoing lumbar spinal 
decompression surgery: A randomized controlled study. World Neurosurg 2019; 
doi.org/10.1016/j.wneu.2019.02.149.  

 
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Wong, et al. Bilateral continuous erector spinae plane blocks for sternotomy in a pediatric 
cardiac patient. J Clin Anesth. 2018 Jun;47:82-8 
 
2.0 OBJECTIVE(S) OF CLINICAL STUDY 
 
 
The feasibility and efficacy of utilizing preoperative erector spinae plane blocks 
(ESPB) to decrease opioid needs/consumption and to decrease numeric rating scale (NRS) 
pain scores in pediatric patients undergoing spinal fusion for adolescent idiopathic scoliosis 
(AIS). 
 
1. What is the feasibility of performing bilateral US-guided ESPBs in this patient population?  
2. What is the rate of recruitment to perform ESPB in this patient population?  
3. What is the rate of adherence to perform the ESPB in this patient population (i.e., number 
who receive the intervention and complete all assessments/ number who enroll)?  
4. Can patients be successfully randomized under the proposed study design?  
5. Can patients be successfully blinded to group allocation under the proposed study 
design?  
6. Are there factors that limit placing ESPBs after induction of anesthesia/prior to surgical 
incision (including time to perform block, time to secure IV access and place arterial line(s), 
surgeon/anesthesiologist preference, and patient-related factors. These include OR work-
flow and timing issues, surgeon request to forego ESPB due to OR delay, and the 
anesthesiologist's assessment of the ultrasound features that may preclude ESPB 
placement)?  
7. What is the incidence of complications for the ESPB in this patient population?  
8. What is the opioid requirement (in morphine equivalents) in the first 24 hours after surgery 
in patients who received ESPB compared to those who did not?  
9. What is the pain burden (in NRS, 0-10) in the first 24 hours after surgery in patients who 
received ESPB compared to those who did not? 
By completing this study, we hope to assess the feasibility of performing this block for this 
particular operation in this patient population. To date, there are a limited number of 
applications of regional anesthesia for pediatric spinal fusion in a comprehensive ERP. 
Further, the optimal block composition is unknown, and the study will help to define this.  
Utilization of this technique may demonstrate an opioid sparing effect, which may have 
multiple benefits including a decrease in opioid-related side effects and increased patient 
satisfaction. If beneficial, the ESPB may become part of routine care for complex spine 
surgery in this patient population. 

 
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3.0 STUDY HYPOTHESES 
1. It will be feasible to perform bilateral ultrasound-guided ESPB as part of a standardized 
pathway of analgesic care for pediatric patients undergoing spinal fusion for adolescent 
idiopathic scoliosis (AIS).  
2. Patients who receive ESPB will have lower opioid requirements and lower NRS pain 
scores in the first 24 hours after surgery, compared to patients who do not have the block. 
4.0 STUDY DESIGN 
4.1 
Endpoints 
4.1.1 
Primary Endpoint 
• 
The primary outcome will be the number of patients who receive bilateral, pre-
incision ESPB (i.e., the rate of adherence, as defined in Specific Aim 3, above 
and as number who receive the intervention and complete all assessments / 
number who enroll). 
 
4.1.2 
Secondary Endpoints 
o 1. Feasibility outcome: rate of recruitment (number enrolled/number 
screened), measured after study end. 
o 2. Feasibility outcome: success of patient and Research Assistant 
blinding to group allocation (based on Bang's Blinding Index, measured at 
24 hours after surgery) 
o 3. Feasibility outcome: type and incidence factors preventing performance 
of block (patient, surgical, anesthetic, and/or work flow related barriers), 
assessed in realtime. 
o 4. Feasibility outcome: attrition (number of patients who enroll, but do not 
receive the intervention and/or study assessments, and the reasons), 
measured and reported in real time. 
o 5. Incidence of intra- and postoperative complications attributed to ESPB 
(interference with intraoperative neuromonitoring, infection, local 
anesthetic toxicity, bleeding/hematoma, extremity weakness) 
o 6. NRS pain scores (after recovery from anesthesia in PACU; and 8, 12, 
and 24 hours post-surgery, and at discharge). 
o 7. Total opioid consumption as measured in oral morphine equivalents 
(OME) (over the first 24 hours post-surgery). 
o 8. Time to first opioid use (oral, or via IV PCA). 
o 9. Incidence of opioid-related side effects (measured via the ORSDS in 
the first 24 hours post-surgery). 
o 10. Patient/parent satisfaction with pain management (at hospital 
discharge, via Likert scale rating from 0-10, where 10 is the highest 
satisfaction)  
 

 
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4.2 
Study Sites 
This study will take place at the main campus of the Hospital for Special Surgery (HSS). 
5.0 STUDY POPULATION 
5.1 
Number of Subjects 
24 
 
5.2 
Inclusion Criteria 
Subjects of either gender will be included if: 
1. Patients undergoing multilevel posterior spinal instrumentation and fusion  
2. Patients between the ages of 10 years old to 19 years old 
3. Undergoing surgery for correction of AIS 
4. Patients under the care of participating surgeons: Drs. Widmann and Blanco 
5. English Speakers 
 
5.3 
Exclusion Criteria 
Subjects will be excluded from the study if: 
• 
Patients younger than 10 years old or greater than 19 years old 
• 
Neuromuscular scoliosis  
• 
Any other HSS surgeon performing the procedure 
• 
History of chronic opioid therapy (>4 weeks) to treat back pain attributed to 
scoliosis tolerance, as defined by CDC criteria (>60 OME daily for over 2 weeks) 
• 
Chronic pain conditions necessitating neuromodulating medications (gabapentin, 
pregabalin) 
• 
Allergy, intolerance or contraindication to any protocol/study 
medication/technique  
• 
Patient or Parent refusal 
• 
Non-English speakers 
6.0 PROCEDURES 
6.1 
Intraoperative Protocol 
Half of patients will be randomized to bilateral ESPB (0.25% bupivacaine plus 2mg 
preservative free dexamethasone) or no block. The maximum allowable dose based on the 
patient’s weight will be divided equally to each side with a maximum of 30mL total per side.  
All patients will undergo anesthetic care under a standardized intraoperative regimen.   The 
postoperative analgesic regimen will likewise be standardized for patients by the pediatric 
anesthesiologist. Global anesthetic management discussion with patient/parent with a set of 
expectations and goals from a pain management perspective (targeted NRS 4/10 or better, 
at rest). The anesthesiologist will describe multimodal analgesia and the role of opioids in 
recovery and pain management. 

 
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Intraoperative: 
▪ 
Sedation: midazolam (up to 2-5 mg, iv) as needed (at the discretion of the 
anesthesiologist). 
▪ 
Induction of general anesthesia to facilitate endotracheal intubation: propofol 
(1-2 mg.kg-1), methadone (0.1-0.2mg.kg-1) with maximum induction dose 
10mg, ketamine (0.5mg.kg-1) with maximum induction dose 25mg, fentanyl 
(1.5-3mcg.kg1) is permitted at the discretion of the anesthesiologist to 
decrease the sympathetic response on induction 
▪ 
Maintenance of general anesthesia: propofol (100-200 mcg.kg.hr-1) titrated by 
the anesthesiologist; remifentanil (0.05-0.5 mcg.kg.min-1) is permitted, titrated 
to effect by the anesthesiologist; ketamine (0.25.mg.kg.hr-1) bolus each hour 
with maximum cumulative dose of 50mg. 
▪ 
Multimodal analgesia: acetaminophen (15 mg.kg-1) during cutaneous closure 
of surgical incision; ketorolac (0.5mg.kg- 1,maximum 30mg each dose) 
▪ 
PONV prophylaxis: dexamethasone (0.5mg.kg-1 up to 10mg) prior to surgical 
incision; ondansetron (0.1 mg.kg-1, maximum 4mg) during cutaneous closure 
of surgical incision. 
▪ 
Prophylaxis against blood loss: tranexamic acid will be given to all eligible 
patients, per HSS standard of care (30 mg.kg-1 bolus over 30 minutes followed 
by and 10 mg.kg.hour-1 infusion until closure of the incision) 
▪ 
Antibiotic prophylaxis: per HSS standard of care (cefazolin as first line agent; 
vancomycin for patients with cephalosporin allergy). 
▪ 
Intravenous fluid administration: at the discretion of the anesthesiologist; 
titrated to hemodynamic status with goal, normovolemia. 
▪ 
External warming device (upper and lower), fresh gas flow humidification, and 
fluid warmer, targeting normothermia. 
 
 
 
6.2 
Postoperative Protocol 
Multimodal analgesia: 
• Dilaudid iv PCA (doses strictly in accordance with pediatric order set according to 
weight, maximum dose of 2 mg.hr-1) 
• Oxycodone 0.05mg.kg-1 q4H PRN mild/moderate pain 
• Oxycodone 0.1mg.kg-1 q4H PRN moderate pain 
• Oxycodone 0.15mg.kg-1 q4H PRN severe pain 
• Ketorolac 0.5mg.kg-1 q6H x6 additional doses (max 30mg each dose) 
• Ibuprofen 10mg.kg-1 q8H after completion of ketorolac 
• Acetaminophen 15mg.kg-1 IV q6H scheduled x3 doses 
• Acetaminophen 15mg.kg-1 PO q6H scheduled after completion of IV APAP 
• Diazepam 0.05-0.1mg.kg-1 PO q6H PRN muscle spasms 
• Nubain 0.05mg.kg-1 q6H PRN itching 

 
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• Ondansetron 0.1mg. kg-1 IV (max 4mg) q8H PRN nausea 
Additional opioids may be administered at the discretion of the anesthesiologist 
▪ 
Physical therapy: goal, POD #1, dangle legs from bedside on POD #0 
Surgical drains and Foley catheter: placement and removal guided by surgical 
team 
▪ 
Oral intake: diet to be advanced as tolerated by the patient with early intake 
encouraged as soon as the patient has recovered, but guided by the surgical team 
 
References: 
Forero M, Adhikary SD, Lopez H, et al. The Erector Spinae Plane Block: A Novel 
Analgesic Technique in Thoracic Neuropathic Pain Regional Anesthesia & Pain 
Medicine 2016;41:621-627. 
Joly V, Richebe P, Guignard B, et al. Remifentanil-induced postoperative 
hyperalgesia and its prevention with small-dose ketamine. Anesthesiology 2005 
Jul; 103(1): 147–55 
Koppert W, Ostermeier N, Sittl R, et al. Low-dose lidocaine reduces secondary 
hyperalgesia by a central mode of action. Pain 2000 Mar; 85(1–2): 217–24 
Pendi, A., et al. Perioperative Ketamine for Analgesia in Spine Surgery: A 
Metaanalysis of Randomized Controlled Trials. Spine (Phila Pa 1976). 2018 March 
01; 43(5): E299–E307. doi:10.1097/BRS.0000000000002318 
Seki, H., et al. Postoperative pain management in patients undergoing 
posteriorspinal fusion for adolescent idiopathic scoliosis: a narrative review. 
Scoliosis and Spinal Disorders (2018) 13:17 
Vigneault, L., Turgeon, A.F., Côté, D. et al. Can J Anesth/J Can Anesth (2011) 58: 
22. https://doi.org/10.1007/s12630-010-9407-0 
6.3 
Data Collection 
The following data will be collected: 
 
Pre-operative/Baseline 
• 
DOB 
• 
MRN 
• 
Race 
• 
ASA Class 

 
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• 
Gender 
• 
Ethnicity 
• 
NRS pain scores at rest and with movement 
• 
Name 
• 
Height, Weight, BMI 
• 
Cobb Angles 
 
 
Surgical procedure (Intra-operative) 
• 
Workflow issues in performing block: time to perform; incidence of 
surgeon request to not perform; ability to perform bilateral blocks 
• 
Surgeon, anesthesiologist  
• 
Surgical duration (time from incision to procedure end) 
• 
Anesthetic duration (time from induction to extubation) 
• 
Blood loss,  
• 
Total fluid administration  
 
 
Post-Operative Day 0 (POD 0) 
• 
PACU: NRS pain scores at rest and with movement 
• 
8 hours post-surgery: NRS pain scores at rest and with movement 
• 
12 Hours post-surgery: NRS pain scores at rest and with movement  
 
Post-Operative Day 1 (POD 1) 
• 
NRS pain scores at rest and with movement  
• 
Cumulative opioid consumption morphine equivalents  
• 
ORSDS 
• 
Blinding assessment  
 
Post-Operative Day of Discharge  
• 
NRS pain scores at rest and with movement  
• 
Cumulative opioid consumption morphine equivalents 
• 
ORSDS 
• 
Patient Satisfaction and Parent satisfaction  
• 
Time of Discharge, length of stay  
• 
Complications occurring during patients stay  
 
  
7.0 STATISTICAL ANALYSIS 
• 
Proposed analysis: This is a feasibility study so power and sample size 
calculations are not appropriate. Classically feasibility studies use a sample 
size of approximately 12 subjects per group (Julious, 2005).   
• 
Interim analysis planned: No 
• 
Alpha level: N/A 
• 
Beta or power level: N/A 

 
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• 
Primary outcome variable estimate: The primary outcome will be descriptive, 
and presented as number of patients/parents approached: number of 
patients/parents enrolling in the study. 
• 
Number of groups being compared: 2 
• 
Effect size or change expected between groups: N/A  
• 
Resulting number per group: 10 
• 
Total sample size required: 20 (maximum plan to enroll: 24) 
 
Descriptive statistics will be used. Data will be presented as mean +/- standard deviation 
(opioid consumption, NRS scores, patient/parent satisfaction). If results are skewed, data 
will be presented as medians (1st and 3rd quartiles).  Normality of distribution will be 
determined via Shapiro-Wilk testing, where significance of >0.05 indicates normally 
distributed data.  Continuous variable will be presented as means and categorical variables 
as counts and percentages 
 
8.0 ADVERSE EVENT ASSESSMENT 
All Adverse Events (AEs) will be reported in the final study report.