Automatic assessment of scoliosis surgery outcome on trunk shape using left-right trunk asymmetry.

PURPOSE: To present a novel set of Left-Right Trunk Asymmetry (LRTA) indices and use them to assess the postoperative appearance of the trunk in Adolescent Idiopathic Scoliosis (AIS) patients. METHODS: We hypothesize that LRTA measurements provide complementary information to existing trunk asymmetry indices when documenting the outcome of scoliosis surgery. Forty-nine AIS patients with thoracic curves who underwent posterior spinal fusion were included. All had surface topography scans taken preoperatively and at least 6 months postoperatively. We documented spinal curvature using Radiographic Cobb angles, scoliometer readings and coronal balance. To evaluate Global Trunk Asymmetry (GTA), we used the standard measures of Back Surface Rotation (BSR) and Trunk Lateral Shift (TLS). To measure LRTA, we identified asymmetry areas as regions of significant deviation between the left and right sides of the 3D back surface. New parameters called Deformation Rate (DR) and Maximum Asymmetry (MA) were measured in different regions based on the asymmetry areas. We compared the GTA and LRTA changes with those in spinal curvature before and after surgery. RESULTS: The GTA indices, mainly TLS, showed improvement for more than 75% of patients. There was significant improvement of LRTA in the shoulder blades and waist regions (95% and 80% of patients respectively). CONCLUSION: We report positive outcomes for LRTA in the majority of patients, specifically in the shoulder blades and waist, even when no reduction of BSR is observed. The proposed indices can evaluate local trunk asymmetries and the degree to which they are improved or worsened after scoliosis surgery.

Incidence of Tether Breakage in Anterior Vertebral Body Tethering.

BACKGROUND: Thoracic anterior vertebral body tethering (TAVBT) is an emerging treatment for adolescent idiopathic scoliosis. Tether breakage is a known complication of TAVBT with incompletely known incidence. We aim to define the incidence of tether breakage in patients with adolescent idiopathic scoliosis who undergo TAVBT. The incidence of tether breakage in TAVBT is hypothesized to be high and increase with time postoperatively. METHODS: All patients with right-sided, thoracic curves who underwent TAVBT with at least 2 and up to 3 years of radiographic follow-up were included. Tether breakage between 2 vertebrae was defined a priori as any increase in adjacent screw angle >5 degrees from the minimum over the follow-up period. The presence and timing of tether breakage were noted for each patient. A Kaplan-Meier survival analysis was performed to calculate expected tether breakage up to 36 months. χ 2 analysis was performed to examine the relationship between tether breakage and reoperations. Independent t test was used to compare the average final Cobb angle between cohorts. RESULTS: In total, 208 patients from 10 centers were included in our review. Radiographically identified tether breakage occurred in 75 patients (36%). The initial break occurred at or beyond 24 months in 66 patients (88%). Kaplan-Meier survival analysis estimated the cumulative rate of expected tether breakage to be 19% at 24 months, increasing to 50% at 36 months. Twenty-one patients (28%) with a radiographically identified tether breakage went on to require reoperation, with 9 patients (12%) requiring conversion to posterior spinal fusion. Patients with a radiographically identified tether breakage went on to require conversion to posterior spinal fusion more often than those patients without identified tether breakage (12% vs. 2%; P =0.004). The average major coronal curve angle at final follow-up was significantly larger for patients with radiographically identified tether breakage than for those without tether breakage (31 deg±12 deg vs. 26 deg±12 deg; P =0.002). CONCLUSIONS: The incidence of tether breakage in TAVBT is high, and it is expected to occur in 50% of patients by 36 months postoperatively. LEVEL OF EVIDENCE: Level IV.

Operative differences for posterior spinal fusion after vertebral body tethering: Are we fusing more levels in the end?

PURPOSE: Little is known about the perioperative characteristics associated with a posterior spinal fusion (PSF) in adolescent idiopathic scoliosis patients previously treated with vertebral body tethering (VBT). We aimed to determine if operative time, estimated blood loss, postoperative length of stay, instrumentation type, and implant density differed in patients that received a PSF (i.e., PSF-Only) or a PSF following a failed VBT (i.e., PSF-VBT). METHODS: We retrospectively assessed matched cohort data (PSF-VBT = 22; PSF-Only = 22) from two multi-center registries. We obtained: (1) operative time, (2) estimated blood loss, (3) postoperative length of stay, (4) instrumentation type, and (5) implant density. Theoretical fusion levels prior to the index procedure were obtained for PSF-VBT and compared to the actual levels fused. RESULTS: We observed no difference in operative time, estimated blood loss, or postoperative length of stay. Instrumentation type was all-screw in PSF-Only and varied in PSF-VBT with nearly 25% of patients exhibiting a hybrid construct. There was no added benefit to removing anterior instrumentation prior to fusion; however, implant density was higher in PSF-Only (1.9 ± 0.2) than when compared to PSF-VBT (1.7 ± 0.3). An additional two levels were fused in 50% of PSF-VBT patients, most of which were added to the distal end of the construct. CONCLUSIONS: We found that operative time, estimated blood loss, and postoperative length of stay were similar in both cohorts; however, the length of the fusion construct in PSF-VBT is likely to be two levels longer when a failed VBT is converted to a PSF.

University of Montreal's Clinician-Investigator Program: A 10-Year Descriptive Evaluation.

PURPOSE: Clinician-investigators have an important role in the development and implantation of new therapies and treatment modalities; however, there have been several reports highlighting a pending shortage in the clinician-investigators' workforce. In Canada, the Royal College has promoted the development of clinician-investigators programs (CIP) to facilitate the training of these individuals. There is currently a paucity of data regarding the outcomes of such programs. This study aims to identify the strengths and areas of improvement of the Montreal University CIP.  Methods: An internet-based 51-question survey was distributed to all the alumni from the University of Montreal CIP. Participation was voluntary and no incentives were provided. The response rate was 64%.  Results: Among respondents, 50% (n=16) had completed their clinical residency and all CIP requirements. The majority of these individuals (63%) had become independent investigators and had secured provincial and national funding. Satisfaction of the respondents was high regarding the overall program (85%), the research skills developed during the CIP (84%) and the financial support obtained during the program (72%). The satisfaction rate regarding career planning was lower (63%).  Conclusion: This survey demonstrates that, while indicators are favorable, some areas still require improvement. Several steps to improve the CIP have been identified; notably, the transition from the CIP to early independent career has been identified as critical in the development of clinician-investigators and steps have been taken to improve this progression.

Is quality of life after surgery for adolescent idiopathic scoliosis affected by the presence of a concomitant low-grade isthmic spondylolisthesis non-surgically treated? A retrospective cohort study.

PURPOSE: The HRQoL after surgery for adolescent idiopathic scoliosis (AIS) is not affected by the presence of concomitant isthmic spondylolisthesis non-surgically treated. Improvement in QoL after surgery was similar for AIS patients with and without concomitant spondylolisthesis. The purpose is to compare preoperative and postoperative Health-Related Quality of Life (HRQoL) scores in operated AIS patients with and without concomitant isthmic spondylolisthesis. METHODS: A retrospective study of a prospective cohort of 464 individuals undergoing AIS surgery between 2008 and 2018 was performed. All patients undergoing surgery for AIS with a minimum 2-year follow-up were included. We excluded patients with prior or concomitant surgery for spondylolisthesis. HRQoL scores were measured using the SRS-22 questionnaire. Comparisons were performed between AIS patients with versus without concomitant spondylolisthesis treated non-surgically. RESULTS: AIS surgery was performed for 36 patients (15.2 ± 2.5 y.o) with concomitant isthmic spondylolisthesis, and 428 patients (15.5 ± 2.4 y.o) without concomitant spondylolisthesis. The two groups were similar in terms of age, sex, preoperative and postoperative Cobb angles. Preoperative and postoperative HRQoL scores were similar between the two groups. HRQoL improved significantly for all domains in both groups, except for pain in patients with spondylolisthesis. There was no need for surgical treatment of the spondylolisthesis and no slip progression during the follow-up duration after AIS surgery. CONCLUSION: Patients undergoing surgical treatment of AIS with non-surgical management of a concomitant isthmic grade I spondylolisthesis can expect improvement in HRQoL scores, similar to that observed in patients without concomitant spondylolisthesis.

Patient outcomes in idiopathic scoliosis are associated with biological endophenotypes: 2020 SOSORT award winner.

PURPOSE: Bracing is the treatment of choice for idiopathic scoliosis (IS), unfortunately factors underlying brace response remain unknown. Clinicians are currently unable to identify patients who may benefit from bracing, and therefore, better molecular stratification is critically needed. The aim of this study is to evaluate IS patient outcomes at skeletal maturity in relation to biological endophenotypes, and determine specific endophenotypes associated to differential bracing outcomes. This is a retrospective cohort with secondary cross-sectional comparative studies. METHODS: Clinical and radiological data were collected from 563 IS patients, stratified into biological endophenotypes (FG1, FG2, FG3) based on a cell-based test. Measured outcomes were maximum Cobb angle at skeletal maturity, and if severe, spinal deformity (≥ 45°) or surgery was attained. Treatment success/failure was determined by standard progression thresholds (Cobb ≥ 45° or surgery; Cobb angle progression ≥ 6°). Multivariable analyses were performed to evaluate associations between endophenotypes and clinical outcome. RESULTS: Higher Cobb angles at maturity for FG1 and FG2 patients were observed (p = 0.056 and p = 0.05), with increased likelihood of ≥ 45° and/or surgery for FG1 (OR = 2.181 [1.002-4.749] and FG2 (OR = 2.141 [1.038-4.413]) compared to FG3. FG3 was 9.31 [2.58-33.61] and 5.63 [2.11-15.05] times more likely for bracing success at treatment termination and based on the < 6° progression criterion, respectively, compared to FG1. CONCLUSION: Associations between biological endophenotypes and outcomes suggest differences in progression and/or bracing response among IS patients. Outcomes were most favorable in FG3 patients. The results pave the way for establishing personalized treatments, distinguishing who may benefit or not from treatment.

Immersive virtual reality vs. non-immersive distraction for pain management of children during bone pins and sutures removal: A randomized clinical trial protocol.

AIMS: To examine the efficacy of an immersive virtual reality distraction compared with an active non-immersive distraction, such as video games on a tablet, for pain and anxiety management and memory of pain and anxiety in children requiring percutaneous bone pins and/or suture removal procedures. DESIGN: Three-centre randomized clinical trial using a parallel design with two groups: experimental and control. METHODS: Study to take place in the orthopaedic department of three children hospital of the Montreal region starting in 2019. Children, from 7-17 years old, requiring bone pins and/or suture removal procedures will be recruited. The intervention group (N = 94) will receive a virtual reality game (Dreamland), whereas the control group (N = 94) will receive a tablet with video games. The primary outcomes will be both the mean self-reported pain score measured by the Numerical Rating Scale and mean anxiety score, measured by the Child Fear Scale. Recalls of pain and anxiety will be measured 1 week after the procedure using the same scales. We aim to recruit 188 children to achieve a power of 80% with a significance level (alpha) of 5%. DISCUSSION: While multiple pharmacological methods have previously been tested for children, no studies have evaluated the impact of immersive virtual reality distraction for pain and anxiety management in the orthopaedic setting. IMPACT: Improved pain management can be achieved using virtual reality during medical procedures for children. This method is innovative, non-pharmacological, adapted to the hospital setting, and user-friendly. TRIAL REGISTRATION: NCT03680625, registered on clinicaltrials.gov.

Use of Vancomycin Powder in the Surgical Treatment of Early Onset Scoliosis Is Associated With Different Microbiology Cultures After Surgical Site Infection.

BACKGROUND: The use of vancomycin powder has been shown to decrease risk of surgical site infection (SSI) in early onset scoliosis (EOS). While there is potential benefit in SSI reduction, there is also theoretical risk in creating increased bacterial resistance to standard treatment regimens. However, the effects of topical vancomycin powder on microbiology in these patients has not been studied. METHODS: A multicenter database for EOS patients was retrospectively analyzed. All patients that underwent surgical treatment with traditional growing rods, magnetically controlled growing rods, vertical expandable prosthetic titanium rib, and Shilla for EOS performed after 2010 were identified (n=1115). Patients that sustained at least 1 SSI after guided growth surgery were assessed (n=104, 9.3%). Patients with culture and antibiotic details were included (n=55). Patients that received vancomycin powder at index surgery were compared with patients that did not. A multivariate regression model was used to control for potential confounders. RESULTS: There were 55 patients included in this study, including 26 males (47%) and 29 females (53%). Mean age at index surgery was 7.2±6.9 years. Vancomycin powder was utilized in 18 cases (33%). Mean time from index surgery to SSI was 2.0±1.3 years. There were 2 cases of wound dehiscence (4%), 7 cases of superficial infection (13%), and 46 cases of deep infection (84%).There were significant differences in overall microbiology results between vancomycin and no vancomycin cohorts (P=0.047). On univariate analysis, the vancomycin powder cohort had a significantly high incidence of cultures without growth (n=7, 39% vs. n=4, 11%, relative risk: 2.063, 95% confidence interval: 0.927-4.591, P=0.028). This association remained significant on multivariate analysis (adjusted odds ratio: 9.656, 95% confidence interval: 1.743-53.494, P=0.009). CONCLUSIONS: In EOS patients undergoing procedures complicated by SSI, the use of vancomycin powder was independently associated with increased risk of no culture growth. Surgeons and infectious disease physicians should be aware and adjust diagnostic and treatment strategies appropriately. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

Radiographic Coronal Imbalance and Shoulder Asymmetry Continue to Improve Between 2 and 5 Years Following Surgery of Adolescent Idiopathic Scoliosis.

BACKGROUND: Managing patients with coronal imbalance (CI) and shoulder height asymmetry following scoliosis surgery can be challenging. Little is known about the course of findings over time and whether they improve or persist. The aim was to report the rate of suboptimal radiographic CI or shoulder asymmetry (SA) at 5 years in patients who were already reported to have CI or SA 2 years after surgery for adolescent idiopathic scoliosis (AIS). METHODS: An AIS database was reviewed for patients with both 2- and 5-year follow-up after surgery. From this cohort, patients with CI>2 cm or SA>2 cm at their 2-year follow-up were identified and reevaluated, using the same parameters, at 5-year follow-up. RESULTS: Of 916 patients, 157 (17%) patients had CI and 69 (8%) patients had SA at 2-year follow-up. At 5 years this improved to 53 (6%) and 11 patients (1%), respectively. CONCLUSIONS: Having coronal or shoulder imbalance 2 years after surgery for AIS does not guarantee continued imbalance 5 years after surgery. Most patients demonstrate some improvement in these measures of clinical deformity. Anticipating the potential course following a postoperative coronal balance and shoulder height differences can help surgeons manage and counsel their patients appropriately. LEVELS OF EVIDENCE: Level II-therapeutic.

Retrospective analysis of fetal vertebral defects: Associated anomalies, etiologies, and outcome.

Our objectives were to describe fetal cases of vertebral defects (VD), assess the diagnostic yield of fetal chromosomal analysis for VD and determine which investigations should be performed when evaluating fetal VD. We performed a retrospective chart review for fetuses with VD seen between 2006 and 2015. Cases were identified from CHU Sainte-Justine's prenatal clinic visits, postmortem fetal skeletal surveys, and medical records. Cases with neural tube defects were excluded. Sixty-six fetuses with VD were identified at a mean gestational age of 20 weeks. Forty-seven (71.2%) had associated antenatal anomalies, most commonly genitourinary, skeletal/limb, and cardiac anomalies. Thirteen mothers (19.7%) had pregestational diabetes (95% CI [10.1%-29.3%]). Fifty-three cases had chromosomal analysis. Three had abnormal results (5.6%): trisomy 13, trisomy 22, and 9q33.1q34.11 deletion. Thirty-four (51.5%) pregnancies were terminated, one led to intrauterine fetal demise and 31 (46.9%) continued to term. Of 27 children who survived the neonatal period, 21 had congenital scoliosis and 3 had spondylocostal dysostosis. Seven had developmental delay. In conclusion, prenatal evaluation of fetuses with VD should include detailed morphological assessment (including fetal echocardiogram), maternal diabetes screening, and chromosomal microarray if non-isolated. Our findings provide guidance about management and counseling after a diagnosis of fetal VD.

Is Anterior Release Obsolete or Does It Play a Role in Contemporary Adolescent Idiopathic Scoliosis Surgery? A Matched Pair Analysis.

STUDY DESIGN: A retrospective analysis of a prospectively collected database was performed. OBJECTIVE: The purpose of this study is to compare 3-dimensional correction associated with the anterior release (AR) and contemporary posterior instrumentation versus posterior-only surgery. SUMMARY OF BACKGROUND DATA: The role of AR as a tool in the treatment of adolescent idiopathic scoliosis (AIS) has seen a decline with the popularization of thoracic pedicle screw instrumentation. METHODS: Five surgeons were queried for all surgical thoracic AIS cases from 2003 to 2010 treated with thoracoscopic AR/fusion and contemporary posterior instrumentation and fusion and thoracic pedicle screw instrumentation (>80% screws) with 2-year follow-up. These cases were then matched with posterior spinal fusion only cases from a multicenter prospective database. The 2 groups were matched on the basis of major curve magnitude within 5 degrees, T5-T12 kyphosis within 9 degrees, and angle of trunk rotation within 9 degrees. Radiographic and clinical parameters were compared for the 2 groups. Continuous variables were analyzed with analysis of variance and categorical dependent variables with the χ test. RESULTS: A total of 47 cases of AR were matched to 47 (1:1 match) posterior spinal fusion cases. Preoperative parameters were similar between groups (P>0.05). Postoperatively, AR cases had a lower major curve (20 vs. 25 degrees, P=0.034; 72% vs. 66% correction, P=0.037). T5-T12 kyphosis was greater in the AR cases (26 vs. 20 degrees; P=0.005). The angle of trunk rotation was similar for the groups. Anchor density was lower in the AR group (1.6 vs. 1.9; P<0.0001). There were 3 complications associated with the AR: 1 pneumothorax and 2 conversions to minithoracotomies for failure to maintain single lung ventilation. CONCLUSIONS: AR improves coronal and sagittal plane correction in contemporary AIS surgery with a satisfactory complication profile with less pedicle screw density required for clinically similar corrections. A further prospective study on the benefits of AR may help define specific indications.

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.

Mechanobiological analysis of porcine spines instrumented with intra-vertebral staples.

OBJECTIVE: To characterize growth plate histology of porcine spines instrumented with a new intra-vertebral staple. METHODS: Spinal segments (T7-T9) previously instrumented with an intra-vertebral staple (experimental group, n=7) or non-instrumented (control group, n=4) underwent average growth rate (AGR), and histomorphometric measurements: heights of proliferative (PZH) and hypertrophic (HZH) growth plate zones, hypertrophic cells height (CH), and the number of proliferative chondrocytes per column (CC). These measurements were done over three regions: (1) left side; (2) middle; (3) right side (instrumented side). The two groups were analyzed by comparing the difference between results for regions 1 and 3 (Dif-R1R3). RESULTS: A significantly higher Dif-R1R3 was found for AGR and HZH for the experimental group as compared with controls. This Dif-R1R3 was also significantly higher for CC at T8 level, CH at T7 level and PZH at both levels. No significant changes for the Dif-R1R3 were observed in the adjacent vertebrae (T11-T12). CONCLUSIONS: This study confirmed the local growth modulation capacity of the intra-vertebral staple, translated at the histomorphometric level by a significant reduction in all parameters, but not in all spinal levels. Further analyses are needed to confirm the regional effect, especially for the intervertebral disc and other connective tissues.

A new ovine model of spine and chest wall deformity at birth with alteration of respiratory system mechanics and lung development: a feasibility study.

PURPOSE: To develop an animal model of spine and chest wall deformity (CWD) at birth and to evaluate its effects on respiratory system mechanics and lung development. METHODS: A spine and CWD was created in utero between 70 and 75 days of gestation in six ovine fetuses by resection of the seventh and eighth left ribs. Two days after birth, respiratory system mechanics was assessed in anesthetized lambs using the flexiVent apparatus, followed by postmortem measurement of lung mechanics as well as histological lung analysis. RESULTS: A range of severity of CWD was found (Cobb angle from 0° to 48°) with a mean decrease in compliance of 47% and in inspiratory capacity of 39% compared to control lambs. Proof-of-concept histological analysis in one lamb showed marked lung hypoplasia. CONCLUSION: Our ovine model represents a pilot proof-of-concept study evaluating the impact of a spine and CWD present at birth on lung respiratory mechanics and development. This study lays down the groundwork for future studies evaluating the impact of these deformities on lung development and potential treatments. These slides can be retrieved under Electronic Supplementary Material.

Long-term follow-up after surgical treatment of adolescent idiopathic scoliosis using high-density pedicle screw constructs: Is 5-year routine visit required?

PURPOSE: The objective of this study is to determine whether routine follow-up 5 years after adolescent idiopathic scoliosis (AIS) surgery is likely to affect postoperative care for patients treated with high-density pedicle screw constructs, when routine 2-year follow-up has been performed. METHODS: We reviewed 80 patients undergoing surgery for AIS using high-density pedicle screw constructs and followed routinely 2 and 5 years after surgery. Quality of life (QOL) was assessed using the SRS-30 outcome questionnaire. Reoperations occurring between 2 and 5 years after surgery were identified. RESULTS: Curve correction and QOL were similar between 2- and 5-year visits. Two patients required revision surgery after presenting during unplanned visits between the 2- and 5-year follow-ups. One patient presented at the routine 5-year visit with an asymptomatic undisplaced rod fracture without loss of correction, and it was decided to follow-up only as needed. CONCLUSIONS: In AIS patients for whom routine follow-up 2 years after surgery using high-density pedicle screw constructs was uneventful, additional routine 5-year follow-up is not likely to affect postoperative care and revision rate. Patients developing complications and needing reoperation between 2 and 5 years after surgery will most likely present during unplanned visits rather than during routine follow-up appointments. Easy access to emergent visits on an as-needed basis is therefore important for this population if routine 5-year follow-up is not planned. These slides can be retrieved under Electronic Supplementary Material.

Criteria for surgical reduction in high-grade lumbosacral spondylolisthesis based on quality of life measures.

PURPOSE: Although surgical reduction in high-grade lumbosacral spondylolisthesis is often performed in young patients, criteria for defining adequate reduction leading to optimal outcomes have yet to be defined. The purpose of this study is to determine if surgical reduction in pelvic balance, slip grade, lumbosacral angle and L5 incidence are associated with quality of life after surgery, based on specific criteria proposed previously in the literature. METHODS: A prospective cohort of 61 patients (14.4 ± 2.7 years) with high-grade lumbosacral spondylolisthesis was followed for a minimum of 2 years after surgery. SRS-22 scores, slip grade, lumbosacral angle, pelvic balance and L5 incidence were assessed before surgery and at the latest follow-up. Multivariable regression analyses were performed using postoperative SRS domain and total scores as the dependent variables. Independent variables consisted of the preoperative SRS scores, and specific criteria of pelvic balance, slip grade, lumbosacral angle and L5 incidence. The influence of slip grade, lumbosacral angle and L5 incidence on pelvic balance was also assessed. RESULTS: Obtaining a balanced pelvis postoperatively was mainly predictive of improved satisfaction with surgery and self-image and also tended to be associated with higher scores for other domains. Improved mental health was associated with reduction to a low-grade slip. Reduction in lumbosacral angle was not predictive of quality of life. Postoperative pelvic balance was mainly associated with preoperative pelvic balance, but there was a tendency for achieving normal pelvic balance when the postoperative L5 incidence was 60° or smaller. CONCLUSIONS: When performing surgery in young patients with high-grade lumbosacral spondylolisthesis, achieving normal pelvic balance is the key because it is associated with improved quality of life. Reduction to a low-grade slip is predictive of improved mental health, but reduction in lumbosacral angle is not associated with postoperative quality of life. There was a tendency for obtaining normal postoperative balance in patients with postoperative L5 incidence 60° or smaller. These slides can be retrieved under Electronic Supplementary Material.

L3 translation predicts when L3 is not distal enough for an "ideal" result in Lenke 5 curves.

PURPOSE: Determining whether to fuse a Lenke 5 curve to L3 or to L4 is often a difficult decision. The purpose of this study was to determine preoperative variables predictive of an "ideal" or "less than ideal" outcome for Lenke 5 curves instrumented to L3. METHODS: A multicentre registry of adolescent idiopathic scoliosis patients was queried for surgically treated Lenke 5 curves with a lowest instrumented vertebra (LIV) of L3 and minimum 2 years of follow-up. Five seasoned surgeons qualitatively rated the 2-year postoperative images as "ideal" or "less than ideal" with respect to correction and alignment. Preoperative and postoperative radiographic variables were compared between the two groups. Multivariate regression analysis was performed to determine variables most predictive of a "less than ideal" outcome. RESULTS: One hundred and thirty-nine patients met criteria. Twenty-three were considered "less than ideal" by ≥ 3 surgeons; 81 were unanimously "ideal". Preoperatively, the "less than ideal" group had significantly stiffer curves, greater apical translation, and greater LIV angulation and translation. Multivariate regression found that preoperative L3 translation (p = 0.009) was the single most important predictor of a "less than ideal" outcome: < 3.5 cm consistently resulted in an "ideal" outcome, while > 3.5 cm risked a "less than ideal" result. CONCLUSION: While multiple variables are important in achieving an "ideal" outcome in Lenke 5 curves, this study found preoperative L3 translation was the most important predictor of success with an L3 translation < 3.5 cm being a potential threshold for selecting L3 as the LIV. These slides can be retrieved under Electronic Supplementary Material.

Predicting lowest hemoglobin level and risk of blood transfusion in spinal fusion surgery for adolescent idiopathic scoliosis.

PURPOSE: The aim of this study was to evaluate the factors associated with timing of lowest hemoglobin (Hb) level and the need for postoperative blood transfusion in posterior spinal fusion for adolescent idiopathic scoliosis. METHODS: We conducted a retrospective review of all adolescent scoliosis patients undergoing posterior spinal fusion at our institution, 2002-2014. Surgery consisted of segmental pedicle screw fixation using multi-level pedicle screws. Blood-saving techniques were used in all patients. Data included Cobb angle, pre- and postoperative Hb levels, preoperative autologous blood donation (PABD), surgery duration, and allogeneic or autologous transfusion. We used linear and logistic regressions for statistical analysis. RESULTS: There were 456 patients (402 female, 54 male), mean age 16 ± 5 years. Lowest Hb was observed on postoperative Days 2 (32.2%) and 3 (33.3%); 45.1% of postoperative transfusions occurred on Day 2. One hundred and eighty-eight (41%) patients who provided PABD had significantly lower preoperative Hb and received more transfusions intraoperatively (22.6% vs. 5.2%) and postoperatively (20% vs. 6.3%) than others. Probability of transfusion increased 49.6 (95% CI 17.40-141.37) times with preoperative Hb < 11 g/dL as compared to preoperative Hb > 14 g/dL. Probability of transfusion increased 4.3- and 9.8-fold when surgery duration exceeded 5 and 6 h, respectively. Probability of transfusion increased 3.3- and 5.3-fold with Cobb angle > 70° and 80°, respectively. CONCLUSIONS: We identified clear patient-specific perioperative parameters that affect risk of perioperative blood transfusion, including Cobb angle, PABD and preoperative Hb. Hb measurement beyond postoperative Day 3 is considered unnecessary unless clinically indicated. These slides can be retrieved under Electronic Supplementary Material.

Restoration of normal pelvic balance from surgical reduction in high-grade spondylolisthesis.

PURPOSE: To investigate the effectiveness of surgical reduction in high-grade spondylolisthesis in maintaining or restoring a normal pelvic balance, as related to the QoL. METHODS: It is a retrospective analysis of prospectively collected data of 60 patients (17 males, 43 females) aged 15 ± 3.1 years who underwent surgery for high-grade spondylolisthesis and were followed for a minimum of 2 years after surgery. Patients with a residual high-grade slip following surgery were referred to the postoperative high-grade (PHG) group, while patients with a residual low-grade slip were referred to the postoperative low-grade (PLG) group. Pelvic balance was assessed from pelvic tilt and sacral slope, in order to identify patients with a balanced pelvis or unbalanced pelvis. The SRS-22 questionnaire was completed before surgery and at last follow-up. RESULTS: Postoperatively, there were 36 patients with a balanced pelvis and 24 patients with an unbalanced pelvis. The improvement in QoL was better in patients with a postoperative balanced pelvis. There were 14 patients in the PHG group and 46 patients in the PLG group. Four of seven patients (57%) in the PHG group and 21 of 26 patients (81%) in the PLG group with a preoperative balanced pelvis maintained a balanced pelvis postoperatively (P = 0.1). None of the patients in the PHG group and 11 of 20 patients (55%) in the PLG group improved from an unbalanced to a balanced pelvis postoperatively (P < 0.05). CONCLUSIONS: Surgical reduction in high- to low-grade slip is more effective in maintaining and restoring a normal pelvic balance postoperatively. These slides can be retrieved under Electronic Supplementary Material.

To distinguish flexible and rigid lumbar curve from MRI texture analysis in adolescent idiopathic scoliosis: A feasibility study.

BACKGROUND: Imaging in side bending, supine, traction, fulcrum, and push prone are examples of methods used to evaluate the curve reduction of scoliotic spine. However, being able to determine spine curve flexibility from MRI would eliminate the need of additional X-ray radiation related to radiograph acquisition in side-bending. PURPOSE/HYPOTHESIS: To find specific texture features of lumbar postural muscles on MRI that can distinguish flexible from rigid lumbar scoliotic curves. We hypothesized that the changes occurring in postural muscles with scoliosis can be seen with MRI. STUDY TYPE: Retrospective study case control. POPULATION: With Institutional Review Board approval and informed consent, 15 adolescents with idiopathic scoliosis and scheduled for surgery were involved. FIELD STRENGTH/SEQUENCE: T1 -weighted MR images were performed on a 1.5T system using a spin echo sequence in the axial direction. ASSESSMENT: The spinal erector, quadratus lumborum and psoas major muscles were analyzed using textural features. STATISTICAL TESTS: Principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) were used to classify the lumbar postural muscles and calculate performance metrics. The lumbar flexibility index, measured from suspension tests, was used as ground truth measurement. RESULTS: The five discriminant features (out of 34 tested features) obtained from PCA were able to keep over 90% of the variability of the dataset. The right and left spinal erector and the left psoas major had the highest performance metrics to classify the spinal curve flexibility, with an accuracy over 0.80, a sensitivity over 0.82, a specificity over 0.68, and a Matthews correlation coefficient over 0.57. DATA CONCLUSION: This study analyzed MRI using texture information of muscle to distinguish flexible from rigid scoliotic curves. Some postural muscle such as the spinal erector and the psoas major are more likely to reflect the curve flexibility of a scoliotic participant. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017.