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Study Design: Retrospective registry analysis., Objective: To examine predictions of individual Scoliosis Research Society-22r (SRS-22r) questions one year after surgery for adolescent idiopathic scoliosis (AIS)., Summary of Background Data: A precision-medicine approach to AIS surgery will inform patients of the likelihood of achieving particular results from surgery, specifically individual responses to the SRS-22r questionnaire., Methods: A multicenter AIS registry was queried for surgical AIS patients treated between 2002 and 2020. Preoperative data collected included standard demographic data, deformity descriptive data, and SRS-22r scores. Postoperative one-year SRS-22r scores were modeled using ordinal logistic regression. The highest probability was the most likely response. Model performance was examined by c-statistics, where c >0.8 was considered excellent. Ceiling effects were measured by the proportion of patients reporting "5" to each question., Results: A total of 3251 patients contributed data to the study; mean age 14.4 (±2.2) years, female 2631 (81%), major thoracic coronal curve 53°, mean lumbar 41°. C-statistic values ranged from 0.6 (poor) to 0.8 (excellent), evidence of varied predictive capabilities. Q17 ("days off work/school," c = 0.84, ceiling achieved 75%) and Q15 ("financial difficulties," c = 0.86, ceiling achieved 82%) had the greatest predictive capabilities while Q11 ("pain medication," c=0.73, ceiling achieved 67%), Q10 ("appearance," c=0.72, ceiling achieved 35%), and Q19 ("attractive," c=0.69, ceiling achieved 37%) performed poorly., Conclusions: Prediction of individual SRS-22r item responses, perhaps most germane to AIS treatment, was poor. The prediction of less relevant outcomes, where ceiling effects are present, was greater as the models chose "5" for all responses. These ceiling effects may limit discrimination and hamper efforts at personalized outcome predictions., Level of Evidence: Level 3., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Study Design: Retrospective cohort., Objective: The aim of this study was to design a risk-stratified benchmarking tool for adolescent idiopathic scoliosis (AIS) surgeries., Summary of Background Data: Machine learning (ML) is an emerging method for prediction modeling in orthopedic surgery. Benchmarking is an established method of process improvement and is an area of opportunity for ML methods. Current surgical benchmark tools often use ranks and no "gold standards" for comparisons exist., Materials and Methods: Data from 6076 AIS surgeries were collected from a multicenter registry and divided into three datasets: encompassing surgeries performed (1) during the entire registry, (2) the past 10 years, and (3) during the last 5 years of the registry. We trained three ML regression models (baseline linear regression, gradient boosting, and eXtreme gradient boosted) on each data subset to predict each of the five outcome variables, length of stay (LOS), estimated blood loss (EBL), operative time, Scoliosis Research Society (SRS)-Pain and SRS-Self-Image. Performance was categorized as "below expected" if performing worse than one standard deviation of the mean, "as expected" if within 1 SD, and "better than expected" if better than 1 SD of the mean., Results: Ensemble ML methods classified performance better than traditional regression techniques for LOS, EBL, and operative time. The best performing models for predicting LOS and EBL were trained on data collected in the last 5 years, while operative time used the entire 10-year dataset. No models were able to predict SRS-Pain or SRS-Self-Image in any useful manner. Point-precise estimates for continuous variables were subject to high average errors., Conclusions: Classification of benchmark outcomes is improved with ensemble ML techniques and may provide much needed case-adjustment for a surgeon performance program. Precise estimates of health-related quality of life scores and continuous variables were not possible, suggesting that performance classification is a better method of performance evaluation., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: The purpose of this study was to determine mid-long-term outcomes (5 years) following surgery for young adult idiopathic scoliosis (YAdIS)., Methods: This is a retrospective review of a prospective, multicenter adult deformity database including patients operated on idiopathic scoliosis by a single posterior approach, age at surgery between 19 and 29 (considered young adults), and 5-year follow-up. Demographic, radiographic and PROMS were analyzed preoperatively, at 2 years and at final follow-up., Results: Forty-two patients were included. Mean preoperative major curve angle was 59.65 ± 18.94. Main coronal curve initial correction was 56.38%, with 6% loss at 5 years. From baseline to 5 years after surgery, there was improvement in all PROMs (P < 0.004)-especially self-image-, except NRS-leg pain. This improvement was present at 6 months for all PROMs except for functional outcomes (SRS-Function and ODI) in which the improvement took place between 6 months and 2 years. In the 2- to 5-year follow-up period, no significant changes were seen in any PROMs. The percentage of patients reaching MCID from baseline at 5 years was: 75% for SRS-image, 45% for SRS-pain, 47.5% for SRS-function, 51.3% for SRS-mental, 42.5% for SRS-total and 15.4% for ODI. Patients reaching PASS at 5 years were: 88.1% for SRS-image, 81% for SRS-pain, 92.9% for SRS-function, 57.1% for SRS-mental, 88.1% for SRS-total, 92.7% for ODI and 69% for NRS pain. 11 minor and 4 major complications were identified., Conclusion: YAdIS surgery resulted in an early and significant improvement in PROMs, especially for self-image, significantly reaching MCID and PASS thresholds. These results were maintained during long-term (5-year) follow-up., (© 2023. The Author(s), under exclusive licence to Scoliosis Research Society.)

Case Presentation: A 13-year-old female with congenital diaphragmatic hernia-associated pulmonary hypertension presented with severe and rapidly progressing scoliosis. The patient suffered from chronic respiratory failure and high risk of hypertensive crisis with potentially life-threating consequences. The scoliosis was treated with a multidisciplinary approach combining preoperative halo-gravity traction, venoarterial extracorporeal membrane oxygenation support and posterior spinal instrumented fusion. After 2 years of follow-up, results are excellent., Conclusions: The treatment combination reported here for the first time aims to limit surgical aggressiveness. It could be an effective and safe approach for treating severe spinal deformities in very fragile patients with high surgical risk., (© 2022. The Author(s), under exclusive licence to Scoliosis Research Society.)

Study Design: A post hoc analysis., Objective: Advances in machine learning (ML) have led to tools offering individualized outcome predictions for adult spinal deformity (ASD). Our objective is to examine the properties of these ASD models in a cohort of adult symptomatic lumbar scoliosis (ASLS) patients., Summary of Background Data: ML algorithms produce patient-specific probabilities of outcomes, including major complication (MC), reoperation (RO), and readmission (RA) in ASD. External validation of these models is needed., Methods: Thirty-nine predictive factors (12 demographic, 9 radiographic, 4 health-related quality of life, 14 surgical) were retrieved and entered into web-based prediction models for MC, unplanned RO, and hospital RA. Calculated probabilities were compared with actual event rates. Discrimination and calibration were analyzed using receiver operative characteristic area under the curve (where 0.5=chance, 1=perfect) and calibration curves (Brier scores, where 0.25=chance, 0=perfect). Ninety-five percent confidence intervals are reported., Results: A total of 169 of 187 (90%) surgical patients completed 2-year follow up. The observed rate of MCs was 41.4% with model predictions ranging from 13% to 68% (mean: 38.7%). RO was 20.7% with model predictions ranging from 9% to 54% (mean: 30.1%). Hospital RA was 17.2% with model predictions ranging from 13% to 50% (mean: 28.5%). Model classification for all three outcome measures was better than chance for all [area under the curve=MC 0.6 (0.5-0.7), RA 0.6 (0.5-0.7), RO 0.6 (0.5-0.7)]. Calibration was better than chance for all, though best for RA and RO (Brier Score=MC 0.22, RA 0.16, RO 0.17)., Conclusions: ASD prediction models for MC, RA, and RO performed better than chance in a cohort of adult lumbar scoliosis patients, though the homogeneity of ASLS affected calibration and accuracy. Optimization of models require samples with the breadth of outcomes (0%-100%), supporting the need for continued data collection as personalized prediction models may improve decision-making for the patient and surgeon alike., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To determine if responses given to each question of the Scoliosis Research Society-22 (SRS22), Oswestry disability index (ODI) and Short Form-36 (SF-36) questionnaires are influenced by the radiological parameters., Methods: Patients enrolled in a multi-centre prospectively collected adult spinal deformity database who had complete SRS22, ODI and SF-36 data at baseline and at one-year follow-up were analysed. The presence of a differential item function of each question within each score in relation to radiological parameters was analysed using a mixed Rasch model with the radiological threshold value(s) determined., Results: Of those patients analysed (n = 1745; 1406 female, average age 51.0 ± 19.8 years), 944 were surgically and 801 were non-surgically treated. For the SRS22, questions (Q) 3, 5 and 18 were sensitive to almost all radiological parameters and the overall score was found sensitive to the Cobb angle. For the ODI, Q3, 6, 9 and 10 were not sensitive to any radiologic parameters whereas Q4 and 5 were sensitive to most. In contrast, only 3 of the SF-36 items were sensitive to radiological parameters., Conclusions: 78% of the SRS-22, 60% of the ODI and 8% of the questions in the SF-36 are sensitive to radiological parameters. Sagittal imbalance is independently associated with a poor overall outcome, but affects mental status and function more than pain and self-image. The assembly of questions responsive to radiological parameters may be useful in establishing a connection between changes in radiologic parameters and HRQL., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Study Design: Prospective case series OBJECTIVE: Results of surgical treatment of complex vertebral transposition "Gamma Deformity" > 180 degrees with halo gravity traction (HGT) and vertebral column resection (VCR). We recently published a novel classification system for complex spine deformities of which complex vertebral transposition > 180 degrees (Gamma; type 3) was described. Halo gravity traction (HGT) has been shown to mitigate surgical risk in complex spine deformity correction and in some cases obviates the need for three-column osteotomy. However, we are not aware of report of its utilization in treating Gamma deformities with or without vertebral column resection (VCR)., Methods: A consecutive series of 13 patients with Gamma deformity (GD) were prospectively enrolled at a single site in West Africa. Standard radiographs and 3D computerized tomography (CT) were done to assess coronal and sagittal vertebral transposition (CVT and SVT). The HGT with 50% of body weight was applied over several weeks followed by VCR. Demographics, operative data, radiographic parameters, and complications data were collected., Results: 13 pts with GD underwent HGT for an avg of 110 days prior to definitive surgery. Etiologies were Congenital-11 pts and Neurofibromatosis-2 pts. Average age: 17.8 years; Pts were reviewed at 3 months post-op and at minimum 2-year follow-up. Preop myelopathy was present in five patients. Pre-op CVT avg 75% and was corrected in all cases post-op. SVT avg 211 deg and improved with HGT by 36% and corrected to 53 deg (74% correction) post-op. Thoracic kyphosis avg -42 deg and averaged 48 deg post-op. Intra-op spinal cord monitoring (SCM) alerts occurred in 8 pts (61%). Post-operative LEM deficits occurred in 5 pts: 2 fully recovered by 3 months and 2 year follow-up, while the remaining 3 improved but had residual motor deficits at final follow-up. There was one post-operative mortality., Conclusion: The management of complex vertebral transposition (Gamma deformity) > 180 degrees with HGT prior to VCR is not only effective in some patients, but also associated with high SCM alerts and neurologic injury rates. Myelopathic patients with thoracic deformities are at higher risk of developing permanent neurologic deficits. Surgeons should be aware of this rare and unusual deformity and consider HGT and VCR bearing in mind the technical challenges and high complication rate.

Background: The prevalence of adolescent idiopathic scoliosis (AIS) in diverse regions of the world has been studied. Access to care varies widely, and differences in disease severity and operative treatment outcomes are not well understood. This study aimed to determine variation in disease presentation and operative complications for AIS patients from an international cohort., Methods: This is a retrospective study carried out at seven surgical centers in the United States (Manhattan and Miami), Ghana, Pakistan, Spain, Egypt, and China. A total of 541 consecutive patients with AIS were evaluated. Preoperative major curve magnitude, operative parameters, and complications were compared among sites using analysis of variance with post hoc tests and Pearson correlation coefficients. Univariate and multivariate forward stepwise binary logistic regressions determined the variables most predictive of complications., Results: Countries with lowest-access to care (Ghana, Egypt, and Pakistan) displayed larger curves, more levels fused, longer operative time (OT), and greater estimated blood loss (EBL) than the other countries (p ≤ .001). Increasing curve magnitude was correlated with greater levels fused, longer OT, and greater EBL in all groups (p = .01). In the univariate regression analysis, Cobb magnitude, levels fused, EBL, and OT were associated with complication occurrence. Only OT remained significantly associated with complication occurrence after adjusting for Cobb magnitude, levels fused, and site (odds ratio [OR] = 1.005, 95% confidence interval 1.001-1.007, p = .003). Complications were greatest in Pakistan and Ghana (21.7% and 13.5%, respectively) and lowest in Miami (6.5%)., Conclusions: Larger curve magnitudes in the least-access countries correlated with more levels fused, longer OT, and greater EBL, indicating that increased curve magnitude at surgery could explain the difference in operative morbidity between low- and high-access countries. With OT as the prevailing predictive factor of complications, we suggest that increased curve magnitude leads to longer OTs and more complications. A lack of access to orthopedic care may be the largest contributor to the postponement of treatment., Level of Evidence: Level II., (Copyright © 2019 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Study Design: Retrospective study of prospectively collected longitudinal data., Objectives: To analyze the Trunk Appearance Perception Scale's (TAPS's) responsiveness to surgical treatment of idiopathic scoliosis (IS)., Summary of Background Data: TAPS is a drawing-based instrument to assess trunk deformity in IS. It shows appropriate metric properties, such as internal consistency and discriminant validity. However, no data on responsiveness to surgical treatment is available., Methods: A total of 109 patients (85.3% females) with IS were included (mean age at surgery 18 years). In all the cases, surgery consisted of posterior spine fusion and instrumentation. The magnitude of the largest curve (MLC) was 63.8° before surgery and 26.3° (correction 58.3%) at a mean follow-up of 20.8 months. Internal and external responsiveness were analyzed on the basis of effect size (ES), standardized response mean (SRM), minimum detectable change (MDC), and correlation between percentage of MLC correction and outcome measure change. Data for TAPS were compared to those of SRS-22 Image domain., Results: TAPS showed somewhat larger internal responsiveness (ES 1.96, SRM 1.73, 86.2% of patients exceeding MDC) than SRS-22 Image scale (ES 1.44, SRM 1.29, 73.4% of patients exceeding MDC). No correlation was found between the percentage of MLC correction and baseline to follow-up change in TAPS or SRS-22 Image scores., Conclusion: The TAPS instrument shows adequate responsiveness to surgical treatment of idiopathic scoliosis and is somewhat larger than SRS-22 Image domain data. The lack of correlation between radiologic correction and clinical improvement indicates that the two outcomes must be independently collected. These data on responsiveness complete the TAPS validation process. TAPS is a valid, reliable, and responsive instrument to evaluate the outcome of surgical treatment of idiopathic scoliosis., Level of Evidence: Level IV., (Copyright © 2017 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.)

Purpose: Adult spinal deformity (ASD) may be classified as idiopathic (ID) or degenerative (DD) (or other) based on classifier's perception, the reliability of and factors inherent to which remain unknown. The aim of this study is to evaluate the inter- and intra-observer reliability of surgeons' perception in differentiating ID from DD and to identify the determinants of this differentiation., Methods: From a multicentric prospective database of ASD, 179 patients were identified with the diagnosis of ID (n = 103) or DD (n = 76); without previous surgery; and a lumbar coronal curve larger than 20°. Standing antero-posterior and lateral X-rays of these patients were sent to five experienced spine surgeons to be identified as DD or ID (or other); followed by a second round after reshuffling. Weighted kappa statistics were used, the strength of agreement for the kappa coefficient was considered as; 0.81-1 = almost perfect, 0.61-0.8 = substantial, 0.41-0.60 = moderate, 0.21-0.40 = fair, 0.01-0.20 = slight, and ≤0 = poor. Patients were then stratified based on the number of agreements on a total of 10 rounds as excellent (10 out of 10), good (more than 7 out of 10) and fair/poor (7 and less). These excellent and good agreements were further compared for additional radiological parameters., Results: Agreement levels were moderate to substantial for intra but mostly fair for inter-observer comparisons. For ID patients, there were 42 cases with excellent and 38 with very good agreement whereas for DD, there were no excellent and only 17 cases with very good agreement. Upon comparison of these (ID vs DD for at least very good cases), it was seen that they were different for some coronal parameters such as lumbar Cobb angle (larger in ID, p < 0.001), central sacral vertical line (CSVL) modifier (C more common in ID, p = 0.007) and presence of rotatory subluxation (less common in DD, p = 0.017), but very different for sagittal parameters (lumbar lordosis, sagittal vertical axis, T2 sagittal tilt, pelvic tilt, sacral slope, and global tilt; increased sagittal imbalance in DD, all p ≤ 0.001)., Conclusion: Surgeons in this study demonstrated reasonable (moderate to substantial) intra-observer agreement, but only fair agreement amongst them. Alarming as it may appear, we should be cautious in interpreting these results based on only radiology and no clinical information. In patients with good agreement, the most consistent radiologic determinant of degenerative ASD appeared to be the presence of sagittal imbalance.

Purpose: Alignment of the cervical spine (CS) in adolescent idiopathic scoliosis (IS) as well as in asymptomatic adult populations has recently been studied and described as being less lordotic in the adolescent IS population. However, few studies have examined the sagittal alignment of the CS in adult IS or its association with other radiological variables and clinical relevance. The aim of this study is to analyse the sagittal alignment of CS in adult IS and its association with age, alignment of the thoracic, lumbar and global spinal column as well as health-related quality of life (HRQOL) parameters., Methods: A retrospective review of prospectively collected data from a multicenter database was performed. Of 468 consecutive adult IS patients, 213 were included in the study; the remainder were excluded due to poor quality X-rays where the CS was not properly visible, or previous surgery. X-rays were measured for the following CS parameters: [Cranial base-C2 (C0-C2) lordosis, C2-C7 lordosis, thoracic (T1) slope, thoracic inlet angle (TIA) and odontoid (Od)-T1 offset using a measurement software]. These measurements were then evaluated for possible associations with patient age and with pre-existing alignment parameters and HRQOL scores using Pearson correlation tests., Results: The average and standard deviations for CS alignment parameters were 32.3° ± 10.2° for C0-C2; 5.7° ± 14.1° for C2-C7; 23.9° ± 11.3° for T1 slope, 70.5° ± 14.7° for TIA and 20.8° ± 16.5° for Od-T1 offset. CS alignment showed a significant (p < 0.05) correlation with age, T kyphosis and several other sagittal alignment parameters such as sagittal vertical axis (SVA), global tilt and T1 sagittal tilt, but not with the HRQOL parameters., Conclusion: The sagittal alignment of the CS in adult IS is less lordotic than the normal average while less kyphotic than that of IS of a younger age. It correlates with age, thoracic kyphosis and some global sagittal alignment parameters. These findings suggest that CS alignment is likely a component of the global sagittal alignment strongly affected by thoracic kyphosis, and most probably does not affect HRQOL by itself.

Study Design: Retrospective analysis of a prospectively collected single-center database., Objective: We describe a modified halo-gravity traction (HGT) protocol for patients with severe spinal deformities in West Africa, and assess the clinical and radiographic outcomes., Summary of Background Data: Three-column osteotomies are frequently used in the correction of severe spinal deformities; however, these can be associated with high complication rates and significant risk for neurological injury. Preoperative traction is one modality used to obtain a partial correction prior to definitive fusion. Low numbers and variability of traction protocols, however, have limited previous reports of sustained HGT., Methods: All patients who underwent HGT in Ghana from April 2012 to August 2013 were reviewed. HGT was started at 20% body weight and increased by 10% per week until 50% body weight was reached by 4 weeks or thereafter as tolerated. Demographic variables, operative data, radiographic parameters, and health-related quality of life scores were collected. A deformity reduction index was calculated at each time point by summing the scoliosis and abnormal kyphosis for each patient and reported as a percentage of the preoperative deformity., Results: Twenty-nine patients underwent HGT for an average 107 days prior to definitive posterior spinal fusion (24 patients) or placement of growing rods (5 patients). The major curve improved from an average 131° to 90° (31%) after HGT, and to an average 57° (56%) postoperatively. Pure kyphotic curves were rigid (flexibility 22% after traction), with a correction index of 3.88, which is similar to historical controls. Deformity correction with HGT plateaued at 63 days. Overall Scoliosis Research Society-22 questionnaire scores improved significantly pretraction versus postoperatively, but there was no change after traction versus before traction. There were 11 pin tract infections, with no neurological complications., Conclusion: HGT is a safe method to partially correct severe spinal deformities prior to a definitive procedure, and may reduce the need for higher risk 3-column osteotomies. Importantly, kyphosis secondary to infection with spontaneous apical ankylosis is relatively resistant to HGT., Level of Evidence: 4.

Study Design: Cross-sectional study in patients with idiopathic scoliosis treated with spinal fusion., Objectives: To measure lumbar spine mobility in the study population; determine low back pain intensity (LBPi), subjective perception of trunk flexibility (TF), and quality of life using validated outcome instruments; and investigate correlations of the lower instrumented vertebra (LIV) with TF, LBPi, and quality of life., Summary of Background Data: The loss of range of motion resulting from spinal fusion might lead to low back pain, trunk rigidity, and a negative impact on quality of life. Nonetheless, these outcomes have not been conclusively demonstrated because lumbar mobility and LIV have not been correlated with validated outcome instruments., Methods: Forty-one patients (mean age, 27 y) with idiopathic scoliosis treated by spinal fusion (mean time since surgery, 135 mo) were included. Patients were assigned to 3 groups according to LIV level: group 1 (fusion to T12, L1, or L2) 14 patients; group 2 (fusion to L3) 13 patients, and group 3 (fusion to L4, L5, or S1) 14 patients. At midterm follow-up, patients completed the Scoliosis Research Society (SRS)-22 Questionnaire and Quality of Life Profile for Spine Deformities to evaluate perceived TF, and rated LBPi with a numerical scale. Lumbar mobility was assessed using a dual digital inclinometer., Results: Group 3 (fusion to L4, L5, or S1) showed statistically significant differences relative to the other groups, with less lumbar mobility and poorer scores for the SRS subtotal (P = 0.003) and SRS pain scale (P = 0.01). Nevertheless, LBPi and TF were similar in the 3 groups. TF correlated with SRS-22 subtotal (r = -0.38, P = 0.01) and pain scale (r = -0.42, P = 0.007) scores, and with LBPi (r = 0.43, P = 0.005)., Conclusions: LIV correlated moderately with lumbar mobility, health-related quality of life (SRS-22), and spinal pain (SRS-22 pain subscale), but not with intensity of pain in the lumbar area or perceived TF.

Introduction: The minimum detectable change (MDC) of the SRS-22 subtotal score is 6.8 points. With the use of this value, patients who have undergone surgery for idiopathic scoliosis can be dichotomized into two groups: the successful (S) group (those who have reached or exceeded this limit) and the unsuccessful (Un-S) group (those in whom the change was smaller). The aim of this study was to analyze the clinical and radiological differences between these patient groups, as well as those related to the surgical technique., Material and Methods: The study included 91 patients (77 women and 14 men, mean age 18.1 years). All patients completed the SRS-22 questionnaire preoperatively and at follow-up (mean 45.6 months). In addition, radiological and surgical data were collected: levels instrumented, number of fused vertebrae, and use of thoracoplasty., Results: Based on the MDC of the SRS-22 subtotal score, patients were assigned to the Un-S group (44 cases, 48.4%) or S group (47 cases). Groups were similar in age, sex, number of fused vertebrae, percentage of patients who underwent thoracoplasty, and the upper and lower instrumented levels. The magnitude of the major curve and percentage of correction after surgery were also similar (Un-S group 62.3º, 53.2%; S group 64.3º, 49.9%). As compared to Un-S group, S patients had a poorer preop score in all the SRS-22 domains, and a clinically significant postop improvement in pain, perceived body image, mental health, and subtotal score. In contrast, the Un-S group showed a worsening of pain, function, mental health, and subtotal score, and a clinically nonsignificant improvement in perceived body image on the follow-up questionnaire. There were no significant differences in the satisfaction domain score between groups (4.36 vs. 4.62). On ROC curve analysis, a preop subtotal score of 74 points predicted allocation to the S or Un-S group at follow-up with 79% sensitivity and 76% specificity., Conclusion: The preop subtotal score of the SRS-22 is a good predictor of the clinical response to surgery.

This study presents a survivorship analysis of Cotrel-Dubousset instrumentation in the surgical treatment of idiopathic scoliosis. Between 1987 and 1995, a total of 133 patients with idiopathic scoliosis received posterior spine fusion and instrumentation with the CD system at our center. The patients' mean age at surgery was 16.5 years (range 11-43 years). The magnitude of the thoracic scoliosis averaged 62.7 degrees (range 40 degrees -125 degrees ) and that of the lumbar curve was 58.8 degrees (range 40 degrees -100 degrees ). On average, 12.2 segments were fused (range 8-17) and, excluding the rods, 14.1 implants were set for each patient (range 10-21). Survivorship analysis was carried out using the Kaplan-Meier method. Implant removal was considered the terminal event, or "death". The effect of several variables on survival rate was determined with the Cox regression method. The patients remained in the study for 56.7 months (range 2-120 months). One-hundred and ten patients were withdrawn ("censored"): 90 "alive" (did not require repeat surgery and attended follow-up control in 1997) and 20 "lost" (did not attend control in 1997). Twenty-three patients attained the terminal event of implant removal for a variety of reasons: acute infection (three cases), late infection (ten cases), implant failure requiring revision (six cases) and local pain (four cases). The survival rate was 95.5% at 3 months, 94.7% at 6 months, 93.9% at 1 year, 91.5% at 2 years, 82.2% at 5 years and 76.5% at 10 years. The magnitude of the curves, total number of implants and number of fused segments did not correlate with survival probability. A positive correlation was found between survival rate and correction loss between surgery and last control. A survival rate of 76.5% at 10 years is unexpectedly low. Current data suggest that the incapacity to maintain correction after initial surgery plays a major roll in the long-term evolution of Cotrel-Dubousset instrumentation.

Purpose: Designed for patients with adolescent idiopathic scoliosis, the SRS-22 is now widely used as an outcome instrument in patients with adult spinal deformity (ASD). No studies have confirmed the four-factor structure (pain, function, self-image, mental health) of the SRS-22 in ASD and under different contexts. Factorial invariance of an instrument over time and in different languages is essential to allow for precise interpretations of treatment success and comparisons across studies. This study sought to evaluate the invariance of the SRS-22 structure across different languages and sub-groups of ASD patients.Methods: Confirmatory factor analysis was performed on the 20 non-management items of the SRS-22 with data from 245 American English-, 428 Spanish-, 229 Turkish-, 95 French-, and 195 German-speaking patients. Item loading invariance was compared across languages, age groups, etiologies, treatment groups, and assessment times. A separate sample of SRS-22 data from 772 American surgical patients with ASD was used for cross-validation.Results: The factor structure fitted significantly better to the proposed four-factor solution than to a unifactorial solution. However, items 14 (personal relationships), 15 (financial difficulties), and 17 (days off work) consistently showed weak item loading within their factors across all language versions and in both baseline and follow-up datasets. A trimmed SRS (16 non-management items) that used the four least problematic items in each of the four domains yielded better-fitting models across all languages, but equivalence was still not reached. With this shorter version there was equivalence of item loading with respect to treatment (surgery vs conservative), time of assessment (baseline vs 12 months follow-up), and etiology (degenerative vs idiopathic), but not age (< vs ≥50 years). All findings were confirmed in the cross-validation sample.Conclusion: We recommend removal of the worst-fitting items from each of the four domains of the SRS-instrument (items 3, 14, 15, 17), together with adaptation and standardization of other items across language versions, to provide an improved version of the instrument with just 16 non-management items. [ABSTRACT FROM AUTHOR]