Prolonged Postoperative Intubation After Spinal Fusion in Cerebral Palsy: Are There Modifiable Risk Factors and Associated Consequences?

BACKGROUND: Instrumented spinal fusion is performed to correct severe spinal deformity that commonly complicates cerebral palsy (CP). Prolonged intubation (PI) is a common perioperative complication, though little is known about the risk factors and consequences of this phenomenon. QUESTIONS/PURPOSES: The purpose of this study was to determine (1) the preoperative and intraoperative risk factors associated with PI after spine surgery for CP; (2) the perioperative and postoperative complications associated with PI; and (3) any long-term impacts of PI with respect to health-related quality of life. PATIENTS AND METHODS: A retrospective case-control analysis of prospectively collected, multicenter data was performed on patients with Gross Motor Function Classification System (GMFCS) 4 or 5 CP who underwent instrumented spinal fusion. Patients extubated on postoperative day (POD) 0 were in the early extubation (EE) cohort and those extubated on POD 3 or later were in the PI cohort. Comparisons were made between PI and EE groups with respect to several preoperative and intraoperative variables to identify risk factors for PI. Multivariate logistic regression was performed to identify independent predictors of this outcome. The postoperative hospital course, rate of complications, and health-related quality of life at 2 years were also compared. RESULTS: This study included 217 patients (52% male individuals; mean age, 14.0±2.8 y) who underwent spinal fusion for CP. In this cohort, 52 patients (24%) had EE and 58 patients (27%) had PI. There were several independent predictors of PI including history of pneumonia [odds ratio (OR), 6.2; 95% confidence interval (CI), 1.6-24.3; P=0.01], estimated blood loss of >3000 mL (OR, 16.5; 95% CI, 2.0-134; P=0.01), weight of <37 kg (OR, 6.4; 95% CI, 1.5-27.1), and Child Health Index of Life with Disabilities (CPCHILD) Communication and Social Interaction score of <15 (OR, 10.8; 95% CI, 1.1-107.3; P=0.04). In addition, PI was associated with a higher rate of perioperative and postoperative respiratory (P<0.001), cardiovascular (P=0.014), gastrointestinal (P<0.001), and surgical site (0.027) complications, in addition to prolonged hospitalization (P<0.001) and intensive care unit stay (P<0.001). CONCLUSIONS: Surgeons should seek to optimize nutritional status and pulmonary function, and minimize blood loss in patients with CP to decrease the risk of PI after spinal fusion. Efforts should be made to extubate patients on POD 0 to decrease the risk of complications associated with PI.

Improving Health-related Quality of Life for Patients With Nonambulatory Cerebral Palsy: Who Stands to Gain From Scoliosis Surgery?

INTRODUCTION: It is unclear what factors influence health-related quality of life (HRQOL) in neuromuscular scoliosis. The aim of this study was to evaluate which factors are associated with an improvement in an HRQOL after spinal fusion surgery for nonambulatory patients with cerebral palsy (CP). METHODS: A total of 157 patients with nonambulatory CP (Gross Motor Function Classification System IV and V) with a minimum of 2-year follow-up after PSF were identified from a prospective multicenter registry. Radiographs and quality of life were evaluated preoperatively and 2 years postoperatively. Quality of life was evaluated using the validated Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD) questionnaire. Patients who had an increase of 10 points or greater from baseline CPCHILD scores were considered to have meaningful improvement at 2 years postoperatively. 10 points was chosen as a threshold for meaningful improvement based on differences between Gross Motor Function Classification System IV and V patients reported during the development of the CPCHILD. Perioperative demographic, clinical, and radiographic variables were analyzed to determine predicators for meaningful improvement by univariate and multivariate regression analysis. RESULTS: A total of 36.3% (57/157) of the patients reported meaningful improvement in CPCHILD scores at 2 years postoperatively. Preoperative radiographic parameters, postoperative radiographic parameters, and deformity correction did not differ significantly between groups. Patients who experienced meaningful improvement from surgery had significantly lower preoperative total CHPILD scores (43.8 vs. 55.2, P<0.001). On backwards conditional binary logistic regression, only the preoperative comfort, emotions, and behavior domain of the CPCHILD was predictive of meaningful improvement after surgery (P≤0.001). CONCLUSION: Analysis of 157 CP patients revealed a meaningful improvement in an HRQOL in 36.3% of the patients. These patients tended to have lower preoperative HRQOL, suggesting more "room for improvement" from surgery. A lower score within the comfort, emotions, and behavior domain of the CPCHILD was predictive of meaningful improvement after surgery. Radiographic parameters of deformity or curve correction were not associated with meaningful improvement after surgery. LEVEL OF EVIDENCE: Level II-retrospective review of prospectively collected data.

Effect of Impairment-Based Rehabilitation on Lower Leg Muscle Volumes and Strength in Patients With Chronic Ankle Instability: A Preliminary Study.

Context: Patients with chronic ankle instability (CAI) have demonstrated atrophy of foot and ankle musculature and deficits in ankle strength. The effect of rehabilitation on muscle morphology and ankle strength has not previously been investigated in patients with CAI. Objective: Our objective was to analyze the effect of impairment-based rehabilitation on intrinsic and extrinsic foot and ankle muscle volumes and strength in patients with CAI. Design: Controlled laboratory study. Setting: Laboratory. Patients: Five young adults with CAI. Intervention: Twelve sessions of supervised impairment-based rehabilitation that included range of motion, strength, balance, and functional exercises. Main Outcome Measures: Measures of extrinsic and intrinsic foot muscle volume and ankle strength measured before and after 4 weeks of supervised rehabilitation. Novel fast-acquisition magnetic resonance imaging was used to scan from above the femoral condyles through the entire foot. The perimeter of each muscle was outlined on each axial slice and then the 2-dimensional area was multiplied by the slice thickness (5 mm) to calculate muscle volume. Plantar flexion, dorsiflexion, inversion, and eversion isometric strength were measured using a hand-held dynamometer. Results: Rehabilitation resulted in hypertrophy of all extrinsic foot muscles except for the flexor hallucis longus and peroneals. Large improvements were seen in inversion, eversion, and plantar flexion strength following rehabilitation. Effect sizes for significant differences following rehabilitation were all large and ranged from 1.54 to 3.35. No significant differences were identified for intrinsic foot muscle volumes. Conclusion: Preliminary results suggest that impairment-based rehabilitation for CAI can induce hypertrophy of extrinsic foot and ankle musculature with corresponding increases in ankle strength.

Low Back Pain in Adolescents: A 1-Year Analysis of Eventual Diagnoses.

BACKGROUND: Back pain in adolescents is very common and often seen in the office for evaluation of potential spinal pathology. Pediatric back pain has often thought to be from serious identifiable causes such as spondylolysis, spondylolisthesis, tumor, or infection. A follow-up analysis of adolescents initially presenting with back pain to their eventual subsequent diagnosis within 1 year has not been reported on a large scale with a national sample. METHODS: A national insurance database (PearlDiver Patient Records Database) was queried for ICD-9 codes to identify patients aged 10 to 19 years with back pain from 2007 to 2010. These patients were tracked for imaging obtained, and eventual development of subsequent associated spinal pathology diagnoses using CPT and ICD-9 codes for up to 1 year after initial presentation. RESULTS: A total of 215,592 adolescents were identified presenting with low back pain (LBP) from 2007 to 2010. Over 80% of adolescents with LBP had no identifiable diagnosis within 1 year. The most common associated subsequent diagnoses were lumbar strain/spasm (8.9%), followed by scoliosis (4.7%), lumbar degenerative disk disease (1.7%), and lumbar disk herniation (1.3%). The rates of all other diagnoses including spondylolysis, spondylolisthesis, infection, tumor, and fracture had <1% association with LBP. CONCLUSIONS: In conclusion, adolescent LBP is a common diagnosis for which underlying serious pathology is rare. The most common diagnosis aside from strain or muscle spasm associated with LBP are scoliosis and degenerative disk disease. Pediatric orthopaedists often are consulted on patients with LBP and should always have high suspicion for potential serious spinal pathology, but should recognize the most common etiologies of back pain in adolescence. LEVEL OF EVIDENCE: Level IV-case series.

Heterogeneity of muscle sizes in the lower limbs of children with cerebral palsy.

INTRODUCTION: Cerebral palsy (CP) is associated with reduced muscle volumes, but previous studies have reported deficits in only a small number of muscles. The extent of volume deficits across lower limb muscles is not known. This study presents an imaging-based assessment of muscle volume and length deficits in 35 lower limb muscles. METHODS: We imaged and segmented 35 muscles in 10 subjects with CP and 8 typically developing (TD) controls using MRI. Muscle volumes were normalized, and Z-scores were computed using TD data. Volume Z-scores and percent deficits in volume, length, and cross-sectional area are reported. RESULTS: Muscle volumes are 20% lower, on average, for subjects with CP. Volume deficits differ significantly between muscles (12%-43%) and display significant heterogeneity across subjects. Distal muscles, especially the soleus, are commonly and severely small. CONCLUSIONS: Heterogeneity across muscles and across subjects reinforces the subject specificity of CP and the need for individualized treatment planning. Muscle Nerve 53: 933-945, 2016.

Imaging appearance of entrapped periosteum within a distal femoral Salter-Harris II fracture.

Salter Harris II fractures of the distal femur are associated with a high incidence of complications, especially premature physeal closure. Many risk factors for this high rate of premature physeal closure have been proposed. More recently, entrapment of periosteum within the physis has been suggested as an additional predisposing factor for premature physeal closure. The radiographic diagnosis of entrapped soft tissues, including periosteum, can be suggested in the setting of a Salter-Harris II fracture when the fracture does not reduce and physeal widening >3 mm remains. We report a patient who sustained a distal femoral Salter-Harris II fracture following a valgus injury. The patient had persistent distal medial physeal widening >5 mm following attempted reduction. A subsequent MRI revealed a torn periosteum entrapped within the distal femoral physis. Following removal of the periosteum, the patient developed a leg length discrepancy which required physiodesis of the contralateral distal femur. We present this case to raise awareness of the importance of having a high index of suspicion of periosteal entrapment in the setting of Salter-Harris II fractures since most consider entrapped periosteum an indication for surgery.

Baclofen pumps do not increase risk of complications following spinal fusion.

PURPOSE: To assess the complication risks associated with intrathecal baclofen (ITB) pumps in cerebral palsy (CP) patients undergoing posterior spinal fusion (PSF) and to determine if timing of pump implantation before or during PSF impacts the risk of complications. METHODS: A prospectively collected multicenter database was retrospectively reviewed to identify CP patients undergoing PSF from 2008 to 2023. Patients were divided into 2 cohorts: those with an ITB pump (ITB cohort) and those without (non-ITB cohort). The ITB cohort was further categorized by placement of the pump prior to or during PSF. Cohorts were then compared in terms of postoperative complications, perioperative complications, and need for revision surgery. RESULTS: Four hundred six patients (ITB n = 79 [53 prior to, 26 during PSF], non-ITB n = 326) were included in this analysis. At an average follow-up of 4.0 years (range 2-10 years), there were no significant differences between the ITB and non-ITB cohorts in the rate of perioperative complications (5.0% vs 6.5%, p = 0.80), revision surgeries (2.5% vs 4.6%, p = 0.54), or any complication type, regardless of whether pumps were placed prior to or during PSF, aside from longer surgical times in the latter group. CONCLUSION: Complication rates are similar for ITBs placed prior to and during PSF. Patients with spastic CP may safely be treated with ITB pumps without increased risks of complication or further reoperation/revision following PSF. LEVEL OF EVIDENCE: Level III.

The pharmacokinetics of methadone in adolescents undergoing posterior spinal fusion.

BACKGROUND: The optimal methadone dosing regimen for children undergoing spinal surgery is uncertain because of sparse pediatric pharmacokinetic data and a paucity of analgesic effect data. The minimum effective analgesic concentration of methadone in opioid naïve adults is 58 mcg · L(-1). METHODS: Adolescents aged 12-19 years undergoing idiopathic scoliosis correction were administered 0.25 mg · kg(-1) racemic methadone IV prior to surgical incision. Arterial blood samples for methadone assay were obtained at 0 min, 5 min, 10 min, 15 min, 20 min, 40 min, 1 h, 2 h, 4 h, 5 h, 6 h, 8 h, 10 h, 12 h, 24 h, and 48 h. Compartment analysis was undertaken using nonlinear mixed effects models. Parameter estimates were standardized to a 70-kg person using allometric models. RESULTS: A three-compartment linear disposition model best described observed time-concentration profiles. Population parameter estimates (between-subjects variability) were central volume (V1) 19.1 (126%) L 70 kg(-1), peripheral volumes of distribution V2 65.5 (60%) L 70 kg(-1), V3 485 (23%) L 70 kg(-1), clearance (CL) 9.3 (11%) L · h(-1) · 70 kg(-1), and inter-compartment clearances Q2 282 (95%) L · h(-1) 70 kg(-1), Q3 139 (42%) L · h(-1) 70 kg(-1). The terminal elimination half-life was 44.4 h. The mean observed methadone concentration was <58 mcg · L(-1) by the first hour after administration. CONCLUSIONS: Current pharmacokinetic parameter estimates in adolescents are similar to those reported in adults. Methadone undergoes rapid redistribution after bolus administration. This may result in plasma concentrations that provide inadequate analgesia postoperatively. We would suggest following the bolus (0.25 mg.kg(-1)) with an infusion (0.1-0.15 mg · kg(-1) · h(-1) for 4 h) during spinal surgery to ensure adequate plasma concentrations for 24 h.

Changes in kinematics, metabolic cost and external work during walking with a forward assistive force.

We examined how the application of a forward horizontal force applied at the waist alters the metabolic cost, kinematics, and external work of gait. Horizontal assist forces of 4%, 8% and 12% of a subject's body weight were applied via our testing apparatus while subjects walked at comfortable walking speed on a level treadmill. Kinematic and metabolic parameters were measured using motion capture and ergospirometry respectively on a group of 10 healthy male subjects. Changes in kinematic and metabolic parameters were quantified and found similar to walking downhill at varying grades. A horizontal assist force of 8% resulted in the greatest reduction of metabolic cost. Changes in recovery factor, external work, and center of mass (COM) movement did not correlate with changes in metabolic rate and therefore were not driving the observed reductions in cost. The assist force may have performed external work by providing propulsion as well as raising the COM as it pivots over the stance leg. Assist forces may decrease metabolic cost by reducing the concentric work required for propulsion while increasing the eccentric work of braking. These findings on the effects of assist forces suggest novel mobility aids for individuals with gait disorders and training strategies for athletes.

The treatment of pediatric supracondylar humerus fractures.

Based on the best current evidence and a systematic review of published studies, 14 recommendations have been created to guide clinical practice and management of supracondylar fractures of the humerus in children. Two each of these recommendations are graded Weak and Consensus; eight are graded Inconclusive. The two Moderate recommendations include nonsurgical immobilization for acute or nondisplaced fractures of the humerus or posterior fat pad sign, and closed reduction with pin fixation for displaced type II and III and displaced flexion fractures.

Outcome assessment in neuromuscular spinal deformity.

Patient-based outcome measures are important tools quantifying the disease-specific and/or global quality of life (QOL) effects of spinal deformity treatment. In patients with neuromuscular disorders such as cerebral palsy, muscular dystrophy, and myelomeningocele, treatment effects must be differentiated from underlying disease functional impairments. In general, the goals of spinal surgery in these patients are to improve QOL by enhancing sitting balance and posture, improving lung and gastrointestinal function, and reducing pain and deformity. In selected patients, improving ambulation and hand function may also be realistic surgical goals. QOL measures specific to both the neuromuscular diagnosis and spinal deformity provide higher quality information on treatment outcomes for a particular patient than standard radiographic measures. This article reviews patient-based outcome measures in spinal deformity patients with neuromuscular disorders, including their development and use in comparative outcome studies in the recent literature.

Running gait biomechanics in females with chronic ankle instability and ankle sprain copers.

Limited evidence exists comparing running biomechanics between individuals with chronic ankle instability (CAI) and those who fully recover (copers). The purpose of this study was to simultaneously analyse running gait kinematics, kinetics, and surface electromyography (sEMG) between ankle sprain copers and individuals with CAI. Twenty-six (13 CAI, 13 Coper) recreationally active females participated and ran shod on an instrumented treadmill at 2.68 m/s. We assessed lower extremity kinematics and kinetics and sEMG amplitude for the fibularis longus, tibialis anterior, medial gastrocnemius, and gluteus medius muscles. Ten consecutive strides from the beginning of the trial were analysed using statistical parametric mapping (SPM) independent t-test. The CAI group had significantly more ankle inversion during 0-6%, 42-53%, and 96-100% of the running stride cycle compared to the coper group. At initial contact (0%), the CAI group was in an inverted ankle position (5.9°±6.8°) and the coper group was in an everted ankle position (-3.2°±5.5°; p = 0.01, d = 1.5). There were no significant differences identified for any other outcome measures. Increased ankle inversion during the swing phase leading into the loading phase is concerning because the ankle is in an open packed position and inversion is a primary mechanism of injury for sustaining a lateral ankle sprain.

Comparison of Treadmill and Overground Walking in Children and Adolescents.

The primary purpose of this study was to compare biomechanical gait variables and perceived gait velocity between overground and treadmill walking conditions among typically developing children and adolescents. Twenty children and adolescents (Mage = 11.4, SD = 2.9 years) walked overground and on a treadmill at a matched comfortable walking speed while a 3-D motion analysis system captured spatiotemporal and kinematic gait parameters. In order to compare perceived gait velocities, we acquired data at self-selected comfortable and fastest walking speeds. Paired t-tests comparing the children's speed and gait in these two different walking conditions revealed significantly higher cadence (p < .001) and shorter stride length (p < .002), during treadmill versus overground walking. In addition, treadmill walking showed statistically significant differences in joint kinematics of ankle excursion and pelvic rotation excursions (p < .001). Participants chose slower speeds on the treadmill than for overground walking when they were asked to select their comfortable and fastest walking speeds (p < .001). Our findings suggest that these differences between treadmill and overground walking in cadence, stride length, and perceived gait velocity should be considered whenever a treadmill is used for gait research within the pediatric population. However, the differences we found in gait kinematics between these two walking conditions appear to be relatively trivial and fell within the common error range of kinematic analysis.

Effects of 4-week impairment-based rehabilitation on jump-landing biomechanics in chronic ankle instability patients.

OBJECTIVE: To determine effects of 4-weeks of impairment-based rehabilitation on lower extremity neuromechanics during jump-landing. DESIGN: Descriptive laboratory study. PARTICIPANTS: Twenty-six CAI subjects (age = 21.4 ± 3.1 sex=(M = 7,F = 19), height = 169.0 ± 8.8 cm, weight = 71.0 ± 13.8 kg) completed 15 jump-landing trials prior to and following 12 supervised rehabilitation sessions. MAIN OUTCOME MEASURES: Frontal and sagittal lower extremity kinematics and kinetics and sEMG amplitudes (anterior tibialis, peroneus brevis, peroneus longus, and medial gastrocnemius). Means and 90% confidence intervals (CIs) were calculated for 100 ms prior to and 200 ms following ground contact. Areas where pre- and post-rehabilitation CIs did not overlap were considered significantly different. Kinematic and kinetic peaks and kinematic excursion were compared with paired t-test (P ≤ 0.05). RESULTS: Following rehabilitation, CAI subjects exhibited less ankle (2.1° (0.8, 3.4), P < 0.01) and hip (2.0° (0.5, 3.7), P = 0.01) frontal plane excursion and lower peak hip abduction (2.5° (0.0, 5.0), P = 0.05). There was less ankle (5.0° (1.7, 8.3), P < 0.01) and knee (3.4° (0.8, 6.0), P = 0.01) sagittal plane excursion following rehabilitation. There was decreased peroneus longus activity from 9 ms to 135 ms post ground contact and decreased peak plantar flexion moment (0.08 N∗m/kg (0.01, 0.13), P = 0.02) following rehabilitation. CONCLUSION: Progressive impairment-based rehabilitation resulted in reductions in kinematic excursion and peroneus longus muscle activity, suggesting a more efficient landing strategy.

Risk factors for gastrointestinal complications after spinal fusion in children with cerebral palsy.

DESIGN: Prospective cerebral palsy (CP) registry review. OBJECTIVES: (1) Evaluate the incidence/risk factors of gastrointestinal (GI) complications in CP patients after spinal fusion (SF); and (2) investigate the validity of the modified Clavien-Dindo-Sink classification. BACKGROUND: Perioperative GI complications result in increased length of stay (LOS) and patient morbidity/mortality. However, none have analyzed the outcomes of GI complications using an objective classification system. METHODS: A prospective/multicenter CP database identified 425 children (mean, 14.4 ± 2.9 years; range, 7.9-21 years) who underwent SF. GI complications were categorized using the modified Clavien-Dindo-Sink classification. Grades I-II were minor complications and grades III-V major. Patients with and without GI complications were compared. RESULTS: 87 GI complications developed in 69 patients (16.2%): 39 minor (57%) and 30 major (43%). Most common were pancreatitis (n = 45) and ileus (n = 22). Patients with preoperative G-tubes had 2.2 × odds of developing a GI complication compared to oral-only feeders (OR 2.2; 95% CI 0.98-4.78; p = 0.006). Similarly, combined G-tube/oral feeders had 6.7 × odds compared to oral-only (OR 6.7; 95% CI 3.10-14.66; p < 0.001). The likelihood of developing a GI complication was 3.4 × with normalized estimated blood loss (nEBL) ≥ 3 ml/kg/level fused (OR 3.41; 95% CI 1.95-5.95; p < 0.001). Patients with GI complications had more fundoplications (29% vs. 17%; p = 0.03) and longer G-tube fasting periods (3 days vs. 2 days; p < 0.001), oral fasting periods (5 days vs. 2 days; p < 0.001), ICU admissions (6 days vs. 3 days; p = 0.002), and LOS (15 days vs. 8 days; p < 0.001). LOS correlated with the Clavien-Dino-Sink classification. CONCLUSION: Gastrointestinal complications such as pancreatitis and ileus are not uncommon after SF in children with CP. This is the first study to investigate the validity of the modified Clavien-Dindo-Sink classification in GI complications after SF. Our results suggest a correlation between complication severity grade and LOS. The complexity of perioperative enteral nutritional supplementation requires prospective studies dedicated to enteral feeding protocols. LEVEL OF EVIDENCE: Therapeutic-level III.

Infection rate after spine surgery in cerebral palsy is high and impairs results: multicenter analysis of risk factors and treatment.

UNLABELLED: Infection is a serious complication of surgery to correct scoliosis in patients with cerebral palsy (CP). We obtained multicenter representative figures for deep and superficial infection rates, analyzed risk factors and treatment outcomes, and compared deformity correction relative to infection. We retrospectively reviewed 157 patients who had posterior spinal fusion for CP at one of eight centers. Preoperative and intraoperative variables were subjected to multivariate analysis to determine factors predictive of infection. There were 16 wound infections (10%; nine deep, seven superficial). Only two study factors predicted infection: higher preoperative white blood cell count (8.5 versus 6.4 [in those without infection] x 10(3)) and use of a unit rod (15% versus 5% for bent rods). Fourteen patients underwent irrigation and débridement procedures. Five infections required 2 months or longer to resolve. Two had implant removal. Final curve correction was lower for those with deep infections than those without (67% versus 53%, respectively). We noted a trend toward greater percentages of pain at last followup in those with deep infection than in those without infection (50% versus 18%, respectively) but the study was not adequately powered to confirm this point. Our infection rate in scoliosis surgery for CP was higher than that for most elective spinal deformity surgery. LEVEL OF EVIDENCE: Level III, retrospective case-control study. See Guidelines for Authors for a complete description of levels of evidence.

The Lumbosacral Takeoff Angle Can Be Used to Predict the Postoperative Lumbar Cobb Angle Following Selective Thoracic Fusion in Patients with Adolescent Idiopathic Scoliosis.

BACKGROUND: Selective fusion of double curves in patients with scoliosis is considered to spare fusion levels. In 2011, we studied the lumbosacral takeoff angle, defined as the angle between the center-sacral vertical line and a line through the centra of S1, L5, and L4. The lumbosacral takeoff angle was shown to moderately correlate with the lumbar Cobb angle, and a predictive equation was developed to predict the lumbar Cobb angle after selective fusions. The purposes of the present study were to validate that equation in a separate cohort and to assess differences in outcomes following selective and nonselective fusion. METHODS: Patients with Lenke 1B, 1C, 3B, or 3C curve patterns undergoing fusion (both selective and nonselective) with pedicle screw constructs and a minimum of 2 years of follow-up were included. Selective fusion was defined as a lowest level of fixation cephalad to or at the apex of the lumbar curve. To validate the previously derived equation, we used this data set and analysis of variance to check for differences between the actual and calculated postoperative lumbar Cobb angles. Pearson correlation, multiple linear regression, and t tests were used to explore relationships and differences between the selective and nonselective fusion groups. RESULTS: The mean calculated postoperative lumbar Cobb angle (and standard deviation) (22.35° ± 3.82°) was not significantly different from the actual postoperative lumbar Cobb angle (21.08° ± 7.75°), with an average model error of -1.268° (95% confidence interval, -2.649° to 0.112°). The preoperative lumbar Cobb angle was larger in patients with deformities that were chosen for nonselective fusion (50.2° versus 38.9°; p < 0.001). Performing selective fusion resulted in a 3.5° correction of the lumbosacral takeoff angle (p < 0.001), whereas nonselective fusion resulted in a 9.3° correction (p < 0.001). CONCLUSIONS: The lumbosacral takeoff angle can be used to predict the residual lumbar Cobb angle and may be used by surgeons to aid in the decision between selective and nonselective fusion. The change in the lumbosacral takeoff angle following selective fusion is small. Improvement in the lumbosacral takeoff angle and coronal balance is greater in association with nonselective fusion. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

BMI change following spinal fusion for neuromuscular scoliosis surgery.

STUDY DESIGN: Retrospective descriptive, multi-center study. OBJECTIVES: We hypothesize that a post-operative weight gain will result in patients who are underweight prior to surgery. Cachexia and low body mass index is common among children with cerebral palsy (CP). Many interventions are undertaken to assist the child in nourishment and to obtain a more normal body mass. Additionally, scoliosis is common among children with CP. In our practice we have noted weight gain post operatively in severely underweight children after spinal fusion. METHODS: We underwent a retrospective review of a CP cohort from a multicenter prospective registry. Percentiles on the CP specific growth chart for which each child belonged were plotted based on the patients' age, weight, gender, GMFCS level, and tube feeding status. We then assessed percentile change in patients between pre-op visit, 1 year, 2 years and for those with available data, 5 years follow up visits. Patients with under two years of follow up, patients with GMFCS III and below, and patients without weight data were excluded. RESULTS: We identified a total of 211 potentially eligible patients from a multicenter prospective registry. 109 had complete 2 years data to analyze and 37 patients had full 5 years data to analyze. We found that patients under the 50th percentile pre-operatively increased their percentile on the CP growth chart for weight 12.1 percentiles (95% CI 6.7, 17.5 p value < 0.001) whereas patients that began at the 50th percentile or above on average lost 2.2 percentiles (95% CI -6.8, 2.3) though the change was not statistically significant (p value 0.330). These changes appeared stable at 5 years. Although regression analysis showed that Cobb correction and pelvic obliquity correction, and hyperlordosis were not independent predictors of the change, we noted that patients with residual curves after surgery of 40° or more experienced 13.3 percentile less weight gain than those with better corrections. CONCLUSIONS: Patients with CP are at risk for cachexia, malnutrition, reflux and other GI disorders. Data presented here suggests that corrective spinal surgery may improve weight percentile in patients who start out at 50th percentile and lower. Patients with 40° or greater of residual scoliosis may benefit less from spinal fusion than those with a better correction. LEVEL OF EVIDENCE: II; Prognostic retrospective cohort study.

Patient-reported Outcomes Following Surgical Intervention for Adolescent Idiopathic Scoliosis: A Systematic Review and Meta-Analysis.

STUDY DESIGN: This was a systematic review and meta-analysis. OBJECTIVE: This study aims to perform a systematic review and quantitative meta-analysis of patient-reported outcome measures after spinal fusion for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Radiographic correction of scoliosis is extensively reported in the literature but there is a need to study the impact of spinal fusion on patient-reported outcome measures. Prior reviews lacked homogeneity in outcome measures, did not perform quantitative meta-analysis of pooled effect size, or interpret the results in light of minimally clinically important difference thresholds. MATERIALS AND METHODS: A systematic review of medical databases identified all studies that prospectively reported Scoliosis Research Society (SRS)-22 questionnaire data after spinal fusion for AIS. We screened 2314 studies for eligibility. Studies were included that reported preoperative and postoperative data at 24- or >60-month follow-up. Studies were excluded that failed to report means and SDs which were needed to calculate Cohen d effect sizes and 95% confidence intervals in estimating the magnitude and precision of the effect. RESULTS: A total of 7 studies met eligibility criteria for inclusion in quantitative meta-analysis of effect sizes and 95% confidence intervals. Patients report large improvements in total score, self-image, and satisfaction; and moderate improvements in pain, function and mental health at 2 and 5 years after spinal fusion for AIS. All domains showed statistically significant improvement at all times except function at >60 months. All domains surpassed the minimally clinically important difference at all times except mental health. CONCLUSIONS: Moderate evidence suggests that spinal fusion improves quality of life for adolescents with idiopathic scoliosis in medium and long-term follow-up. Our results may help inform patient expectations regarding surgery. OCEMB LEVEL OF EVIDENCE: Level I-systematic review and meta-analysis of prospective studies.

Angular momentum synergies during walking.

We studied the coordination of body segments during treadmill walking. Specifically, we used the uncontrolled manifold hypothesis framework to quantify the segmental angular momenta (SAM) synergies that stabilize (i.e., reduce the across trials variability) the whole body angular momentum (WBAM). Seven male subjects were asked to walk over a treadmill at their comfortable walking speed. A 17-segment model, fitted to the subject's anthropometry, was used to reconstruct their kinematics and to compute the SAM and WBAM in three dimensions. A principal component analysis was used to represent the 17 SAM by the magnitudes of the first five principal components. An index of synergy (DeltaV) was used to quantify the co-variations of these principal components with respect to their effect on the WBAM. Positive values of DeltaV were observed in the sagittal plane during the swing phase. They reflected the synergies among the SAM that stabilized (i.e., made reproducible from stride to stride) the WBAM. Negative values of DeltaV were observed in both frontal and sagittal plane during the double support phase. They were interpreted as "anti-synergies", i.e., a particular organization of the SAM used to adjust the WBAM. Based on these results, we demonstrated that the WBAM is a variable whose value is regulated by the CNS during walking activities, and that the nature of the WBAM control changed between swing phase and double support phase. These results can be linked with humanoid gait controls presently employed in robotics.