A classification algorithm for prioritizing surgery in Pediatric patients with idiopathic scoliosis when Long Surgical delays are expected.

PURPOSE: To identify the clinical phenotypes associated with the rate of progression while waiting for surgery and propose a classification scheme for identifying subgroups of patients to prioritize for surgery when long surgical delays are expected. METHODS: We reviewed the clinical and radiographic data of a prospective cohort of patients scheduled for IS surgery from 2004 to 2020 with a minimum 1-year wait prior to surgery. Candidate predictors consisted of age, sex, Risser sign, menarchal status, angle of trunk rotation, scoliotic curve type, and main Cobb angle at baseline when scheduled for surgery. Univariate and Regression Tree analysis were performed to identify predictors associated with the annual curve progression rate in the main Cobb angle between baseline and surgery. RESULTS: There were 214 patients (178 females) aged 15 ± 2 years, with a Risser sign 3.4 ± 1.6 and a main Cobb angle 55°±10° at baseline. The average wait prior to surgery was 1.3 ± 0.4 years. Only the Risser sign, menarchal status and sex were significantly associated with the annual progression rate. We have identified 3 clinically and significantly different groups of patients presenting slow (3 ± 4°/yr if Risser sign 3 to 5), moderate (8 ± 4°/yr if female with Risser sign 0 to 2 and post-menarchal), and fast (15 ± 10°/yr if Risser sign 0 to 2 and premenarchal or male) progression rates. CONCLUSION: We present an evidence-based surgical prioritization algorithm for pediatric idiopathic scoliosis that can easily be implemented in clinical practice when long surgical delays are expected.

Artificial Intelligence Measurement of Preoperative Radiographs in Adolescent Idiopathic Scoliosis Based on Multiple-View Semantic Segmentation.

STUDY DESIGN: Cross-sectional study. OBJECTIVES: Imaging classification of adolescent idiopathic scoliosis (AIS) is directly related to the surgical strategy, but the artificial classification is complex and depends on doctors' experience. This study investigated deep learning-based automated classification methods (DL group) for AIS and validated the consistency of machine classification and manual classification (M group). METHODS: A total of 506 cases (81 males and 425 females) and 1812 AIS full spine images in the anteroposterior (AP), lateral (LAT), left bending (LB) and right bending (RB) positions were retrospectively used for training. The mean age was 13.6 ± 1.8. The mean maximum Cobb angle was 46.8 ± 12.0. U-Net semantic segmentation neural network technology and deep learning methods were used to automatically segment and establish the alignment relationship between multiple views of the spine, and to extract spinal features such as the Cobb angle. The type of each test case was automatically calculated according to Lenke's rule. An additional 107 cases of adolescent idiopathic scoliosis imaging were prospectively used for testing. The consistency of the DL group and M group was compared. RESULTS: Automatic vertebral body segmentation and recognition, multi-view alignment of the spine and automatic Cobb angle measurement were implemented. Compare to the M group, the consistency of the DL group was significantly higher in 3 aspects: type of lateral convexity (0.989 vs 0.566), lumbar curvature modifier (0.932 vs 0.738), and sagittal plane modifier (0.987 vs 0.522). CONCLUSIONS: Deep learning enables automated Cobb angle measurement and automated Lenke classification of idiopathic scoliosis whole spine radiographs with higher consistency than manual measurement classification.

Comparison of three artificial intelligence algorithms for automatic cobb angle measurement using teaching data specific to three disease groups.

Spinal deformities, including adolescent idiopathic scoliosis (AIS) and adult spinal deformity (ASD), affect many patients. The measurement of the Cobb angle on coronal radiographs is essential for their diagnosis and treatment planning. To enhance the precision of Cobb angle measurements for both AIS and ASD, we developed three distinct artificial intelligence (AI) algorithms: AIS/ASD-trained AI (trained with both AIS and ASD cases); AIS-trained AI (trained solely on AIS cases); ASD-trained AI (trained solely on ASD cases). We used 1612 whole-spine radiographs, including 1029 AIS and 583 ASD cases with variable postures, as teaching data. We measured the major and two minor curves. To assess the accuracy, we used 285 radiographs (159 AIS and 126 ASD) as a test set and calculated the mean absolute error (MAE) and intraclass correlation coefficient (ICC) between each AI algorithm and the average of manual measurements by four spine experts. The AIS/ASD-trained AI showed the highest accuracy among the three AI algorithms. This result suggested that learning across multiple diseases rather than disease-specific training may be an efficient AI learning method. The presented AI algorithm has the potential to reduce errors in Cobb angle measurements and improve the quality of clinical practice.

Exploring vertebral bone density changes in a trunk with adolescent idiopathic scoliosis: a mechanobiological modeling investigation of intact and unilaterally paralyzed muscles.

This study aimed to elucidate the vertebral bone density variations associated with adolescent idiopathic scoliosis (AIS), specifically examining the impact of unilateral muscle paralysis using an integrated approach combining Frost's Mechanostat theory, a three-dimensional subject-specific finite element model and a musculoskeletal model of the L2 vertebra. The findings revealed a spectrum of bone density values ranging from 0.29 to 0.31 g/cm3, along with vertebral micro-strain levels spanning from 300 to 2200, consistent with existing literature. Furthermore, the ratio of maximum von Mises stress between the concave and convex side in the AIS model with intact muscles was approximately 1.08, which decreased by 4% due following unilateral paralysis of longissimus thoracis pars thoracic muscle. Overall, this investigation contributes to a deeper understanding of AIS biomechanics and lays the groundwork for future research endeavors aimed at optimizing clinical management approaches for individuals with this condition.

Patient-Specific Rods in Adolescent and Adult Spinal Deformity Surgery: A Narrative Review.

Spinal deformity surgery often requires complex surgical interventions that can have a drastic effect on both patient quality of life and functional capacity. Modern-day corrective solutions for these deformities include spinal osteotomies, pedicle screw instrumentation, and dual/multirod constructs. These solutions are efficacious and are currently considered standard practice for spinal surgeons, but they lack individualization. Patient-specific rods (PSRs) are a novel technology that attempts to offer a personalized approach to spinal deformity correction based on preoperative computerized tomography scans. Moreover, PSRs may offer several advantages to conventional rods, which include achievement of desired rod contour angles according to surgical planning alignment goals, reduced operative time, and reduced blood loss. In adolescent idiopathic scoliosis, those instrumented with PSR have observed coronal Cobb reductions up to 74%. In adult spinal deformity, PSRs have offered superior correction in radiographic parameters such as sagittal vertical axis and pelvic incidence minus lumbar lordosis. However, there still remains a paucity of research in this area, mainly in health care expenditure, cost-effectiveness, and longitudinal clinical outcomes. The purpose of this article is to survey the current body of knowledge of PSR instrumentation in both adolescent and adult spinal deformity populations. The current strength, limitations, and future directions of PSRs are highlighted throughout this article.

Improving prediction of progression of idiopathic scoliosis based on curve size and skeletal maturity.

PURPOSE: To define the risk of curve progression of idiopathic scoliosis (IS) to 35°, 40°, 45°, and 50° based on current curve magnitude and Sanders stage for boys and girls, using a large cohort of patients and encounters, to improve granularity and allow more accurate estimations to guide treatment. METHODS: Retrospective analysis of a prospectively collected scoliosis database. Generalized estimation equation logistic regression models estimated probabilities of curve progression to 35°, 40°, 45°, and 50° based on starting curve size and Sanders stage. Probabilities and their 95% confidence intervals were calculated for each combination of variables to each endpoint separately for boys and girls. RESULTS: A total of 309 patients (80% girls) were included. Starting curve size and Sanders stage were significant predictors for progression in both sexes (all P ≤ 0.04). Higher starting curve sizes and lower Sanders stages were associated with greater odds of progression. Risk of progression was still present even at higher Sanders stages. CONCLUSION: IS curves follow a predictable pattern, having more risk for progression when curves are larger and Sanders stages are smaller. Risk of curve progression is a spectrum based on these factors, indicating some risk of progression exists even for many smaller curves with higher Sanders stages. The improved granularity of this analysis compared to prior efforts may be useful for counseling patients about the risks of curve progression to various curve size endpoints and may aid shared decision-making regarding treatments. LEVEL OF EVIDENCE OR CLINICAL RELEVANCE: Level III: retrospective cohort study.

Bilateral ultrasound-guided erector spinae plane block for postoperative analgesia in paediatric idiopathic scoliosis patients undergoing posterior spine fusion surgery: a randomized controlled trial.

PURPOSE: Major spinal surgery causes severe pain. We examined the ability of erector spinae plane block (ESPB) to alleviate pain after posterior spinal fusion (PSF) in paediatric scoliosis patients. METHODS: Seventy-two patients who underwent PSF were randomized into a preoperative ultrasound-guided ESPB group or a no-block control group. The composite primary outcome was the area under the curve (AUC) of the numerical rating scale (NRS) score in the first 24 h after surgery and the number of parent-controlled intravenous analgesia (PCIA) boluses administered 24 h after surgery. The secondary outcomes included the NRS score, opioid consumption, rescue analgesia, adverse events, and quality of recovery. RESULTS: The AUC-NRS at rest was 62 (13) in the ESPB group and 89 (13) in the control group (P < 0.001). There were 15 (5) 24-h PCIA boluses administered in the ESPB group and 30 (7) in the control group (P < 0.001). Compared with those in the control group, the NRS scores at rest were lower in the ESPB group at 0, 3, 6, and 9 h postoperatively, and the NRS scores during movement were lower in the ESPB group at 0, 3, 6, 9 and 12 h postoperatively. The ESPB group showed a lower need for PCIA than did the control group at 0-6, 6-12, 12-18 and 1-24 h postoperatively. In the ESPB group, fewer patients required rescue analgesics, and patients exhibited a higher quality of recovery. CONCLUSION: Preoperative ESPB improves postoperative analgesia in paediatric scoliosis patients who underwent PSF. TRIAL REGISTRATION NUMBER: ChiCTR2300074505. DATE OF REGISTRATION: August 8, 2023.

Improvement of pulmonary function parameters in female patients with adolescent idiopathic scoliosis by Schroth rehabilitative therapy.

Objective: This study investigates if an inpatient rehabilitation therapy (brace therapy and Schroth therapy) for six weeks contributes to an improvement in lung function of the patients. Design: Retrospective study. Setting: Scoliosis rehabilitation clinic "Asklepios Katharina-Schroth-Klinik" (Bad Sobernheim, Germany). Participants: In 253 female patients a lung function examination was performed at entry and at the end of their inpatient rehabilitation stay. Of these, 61 patients underwent Schroth therapy (group 1); 192 patients underwent the combination of brace and Schroth therapy (group 2). Intervention: Lung function parameters under the influence of Schroth and Schroth and brace therapy within a rehabilitative stay. Main measures: The parameters of IVC (inspiratory vital capacity), FVC (forced vital capacity), FEV1 (forced expiratory volume in 1 s) and the Tiffeneau index (FEV/FVC) related to patient-specific reference values were evaluated with regard to potential ventilation disorders. Results: There were significant improvements for IVC +2.56 %, FVC +3.99 %, FEV1 +2.36 % for the first stay (IVC and FVC 2nd, 3rd stay). The comparison of patients with vs. without additional brace therapy showed no significances. For the long-term analysis the parameters approached the reference values of age-matched, healthy female subjects. The greater the Cobb angle in the thoracic region, the significantly worse almost each of the measured parameters are. Conclusion: An inpatient rehabilitation therapy contributes to an improvement in lung function (IVC, FVC and FEV1). A second, and even a third, follow-up stay still led to a measurable improvement in lung function, albeit to a lesser extent.

Readmission rate after adult scoliosis surgery on primary cases over 45 years-old with long term follow-up.

PURPOSE: Scoliosis surgery is becoming increasingly frequent. Rate of readmission is little discussed in the literature. It is an interesting data for the patient's information and for public authorities to calculate cost-effectiveness. Aim of the study was to evaluate rate and causes of short and long-term readmissions in patients > 45 years old operated on for a scoliosis primary cases, then to look for predictors of these readmissions. METHODS: In this monocentric retrospective cohort study, over 45 years-old scoliosis primary cases operated on between 2015 and 2018 and with a minimum of 2 years follow-up were included. The number of readmissions and their causes were analyzed. Rehospitalized patients (RH) were then compared to non-rehospitalized patients (NRH). Risk factors were sought using a multivariate analysis by logistic regression. RESULTS: 105 patients were included (90% female; 64 ± 8 years). 56% were readmitted at least once. Main cause of readmission as pseudarthrosis (70%). Among the RH patients, fifty-eight required at least one revision. We found no significant difference between RH and NRH, apart from the rate of immediate post-operative medical complications which was significantly higher in RH (17% (n = 11) vs. 4% (n = 2), p = 0.04). According to multivariate analysis, BMI and age were found as predictors of readmission of mechanical origin, and BMI for readmissions of septic origin. CONCLUSION: The readmission rate after scoliosis surgery was 56%. The main cause was pseudarthrosis. Rehospitalized patients had more immediate post-operative medical complications. The elderly and overweight patients are more likely to be readmitted for mechanical or septic reasons.

Three-Level Concavity Apical Pediculectomy During Intraoperative Neuromonitoring Loss: Following the Checklist Resulted in an Ambulatory Patient.

Adolescent idiopathic scoliosis is the most common form of scoliosis, with severe cases leading to a decline in patients with worsening angulation of deformity. Technical nuances of spinal flexibility and cord type based on the extent of the deformity may impact operating safety and outcome, with risks including neurological loss during and after surgical intervention. Here we present a case of posterior osteotomy and correction of a patient with adolescent idiopathic scoliosis with a T2 - L3 fusion in which transcranial motor evoked potentials (TcMEPs) and somatosensory evoked potentials (SSEPs) were lost intraoperatively, thus requiring application of operative consensus guidelines for the loss of neuromonitoring data. Particularly, the discussion focuses on the decision-making process that resulted in the complete recovery of TcMEPs and SSEPs post-operatively.

Management Principles in a Case of True-positive Loss of Neuromonitoring Signals during Scoliosis Surgery: A Case Report.

Introduction: Multimodal intraoperative neuromonitoring (IOM) is essential in scoliosis surgery. This is affected by misplaced instrumentation, cord trauma, hemodynamic instability, and anesthesia. We present an irreversible loss of IOM without identifiable intra-operative cause to highlight its occurrence and discuss post-operative investigations and management. Case Report: A 14-year-old girl with adolescent idiopathic scoliosis, no co-morbidities, and normal spinal magnetic resonance imaging (MRI) underwent posterior spinal fusion. During screw placement, bilateral motor evoked potentials (MEPs) and right somatosensory evoked potentials (SSEPs) were lost in the legs. All screws were removed with no evidence of cortical breach. Left leg responses gradually improved, but there was no recovery of right leg SSEPs or MEPs. Subsequently, the procedure was abandoned. The patient had reduced right leg strength (3/5) and sensation with the left leg was normal. Immediate post-operative spinal MRI identified no abnormality. Computed tomography (CT) showed no cortical breach with satisfactory pedicle screw tracts. Repeat MRI (day 7) showed high T2-signal within the cord at T11 indicating ischemia. Gradual neurological recovery occurred and on day 15, repeat neurophysiology found reproducible SSEPs and MagStim MEPs. The patient underwent revision posterior fusion with single rod correction without complication and IOM was maintained. By day 24, the patient had 5/5 power and normal sensation in both legs. Good scoliosis correction was achieved and maintained at 3-year follow-up. Conclusion: This patient represents a vascular event affecting the lower spinal cord and highlights the role of sequential imaging and pre-operative neurophysiology including MagStim in deciding when to proceed with revision surgery while reducing risk using conservative techniques.

Curve progression following selective and nonselective spinal fusion for adolescent idiopathic scoliosis: are selective fusions stable?

PURPOSE: The purpose of this study is to compare postoperative outcomes between selective and non-selective fusions longitudinally over the first five postoperative years. METHODS: Patient parameters were retrieved from a multicenter, prospective, database. Patients with Lenke 1-6, B and C deformities were included. Patients were stratified into 2 groups: selective fusion (SF), if the last instrumented vertebra (LIV) was at or cranial to the lumbar apex, or non-selective fusion (NSF). Differences in coronal and sagittal radiographic outcomes were assessed with generalized linear models (GLMs) at 1-, 2- and 5- year postoperative outcomes. Five-year postoperative categorical radiographic outcomes, flexibility, scoliosis research society scores (SRS), and reoperation rates were compared between groups. Matched cohorts were created for subgroup analysis. RESULTS: 416 (SF:261, NF:155) patients, including 353 females were included in this study. The mean preoperative thoracic and lumbar Cobb angles were 57.3 ± 8.9 and 45.3 ± 8.0, respectively. GLMs demonstrated greater postoperative coronal deformity in the SF group (p < 0.01); however, the difference between groups did not change overtime (p > 0.05) indicating a relatively stable postoperative deformity correction. The SF group had a greater incidence of lumbar Cobb ≥ 26 degrees (p < 0.01). The NSF group demonstrated worse forward and lateral flexibility at 5-year postoperative outcome (p < 0.05). There was no difference in postoperative SRS scores between the SF and NSF groups. Reoperation rates were similar between groups. CONCLUSION: Selective fusion results in greater coronal plane deformity; however, this deformity does not progress significantly over time compared to non-selective fusion. Selective spinal fusion may be a beneficial option for a larger subset of patients than previously identified. LEVEL OF EVIDENCE: III.

Axial rod slip at the end-of-construct screw in scoliosis surgery: relevance, occurrence and prevention.

PURPOSE: Despite standardized biomechanical tests for spinal implants, we recently recognized pedicle screw failure to maintain the rod fixated as a clinical concern in scoliosis surgery. This occurrence study investigates the risk and magnitude of axial rod slip (ARS), its relation with technique and preventive measures. METHODS: Retrospective multicenter review of all primary scoliosis cases (2018-2020) with > 1 year FU from three centers, instrumented with uniplanar screws and 5.5 mm CoCr rods (Mesa 2, Stryker Corporation, Kalamazoo, MI, USA). ARS was defined as > 1 mm change in residual distal rod length from the screw in the lowest instrumented vertebra (LIV) and assessed by two independent observers. Slip distance, direction, relation to distal screw density and time of observation were recorded, as well as the effect of ARS on caudal curve increase. To prevent slip, more recent patients were instrumented with a different end-of-construct screw (Reline, NuVasive Inc. San Diego, CA, USA) and analyzed for comparison. RESULTS: ARS risk was 27% (56/205) with a distance of 3.6 ± 2.2 mm, predominantly convex. 42% occurred before 4 months, the rest before 1 year. The caudal curve substantially increased three times more often in patients with ARS. Interobserver reliability was high and slip was in the expected direction. ARS was unrelated to distal screw density. Remarkable variation in ARS rates (53%, 31%, 13%) existed between the centers, while there was no difference in mean screw density (≈1.3 screws/level) or curve correction (≈60%). Revision surgery for ARS was required in 2.9% (6/207). Using the different end-of-construct screw, ARS risk was only 2% (1/56) and no revisions were required. CONCLUSION: This study demonstrates the prevalence of axial rod slip at the end of construct in scoliosis surgery and its clinical relevance. While minimal ARS can be subclinical, ARS should not be mistaken for adding on. The most severe ARS predominantly occurred convex at the high-loaded distal screw when L3 was the LIV. Longer constructs (LIV L3 or L4) have a higher risk of ARS. The minimal risk of ARS with another end-of-construct screw underscores the influence of screw type on ARS occurrence in our series. Further research is essential to refine techniques and enhance patient outcomes.

Effects of spinal mobilisation in adolescent idiopathic scoliosis: A randomised controlled trial.

AIM: The aim of this study was to evaluate the effects of spinal mobilisation on curvature magnitude, angle of trunk rotation (ATR) and pulmonary function in adolescents with idiopathic scoliosis (AIS). METHODS: Conducted as a double-blind randomised controlled trial, the study included 40 patients with AIS (Cobb angles 10°-25°) randomised to experimental (n = 20; female = 12, male = 8; age = 12.9 ± 1.8 mean ± SD) and control (n = 20; female = 13, male = 7; age = 12.85 ± 1.81 mean ± SD) groups. The experimental group received spinal mobilisation for 30 min per session followed by 60 min of core stabilisation exercises (CSE), twice a week for 10 weeks. The control group received CSE only at the same frequency and duration. Evaluation of Cobb angle, ATR and pulmonary function tests (PEF: Peak Expiratory Flow, FEV1: Forced Expiratory Volume in 1 s, FVC: Forced Vital Capacity, and FEV1/FVC: Tiffeneau index) were performed at baseline and after the intervention. RESULTS: Both groups showed significant improvements in Cobb angle, ATR, PEF and FVC, with the experimental group showing significantly greater improvements in Cobb angle (-7.65 ± 3.17) and ATR (-2.5 ± 1.43) compared to the control group (P < 0.05). In addition, while the control group showed no change in FEV1, the experimental group showed improvement. There was no change in FEV1/FVC ratio in either group. CONCLUSION: These results indicate that adding spinal mobilisation to treatment sessions can effectively reduce the magnitude of curvature and improve scoliosis-related problems in the short term.

Applications of artificial intelligence for adolescent idiopathic scoliosis: mapping the evidence.

PURPOSE: Adolescent idiopathic scoliosis (AIS) is a common spinal deformity with varying progression, complicating treatment decisions. Artificial intelligence (AI) and machine learning (ML) are increasingly prominent in orthopedic care, aiding in diagnosis, risk-stratification, and treatment guidance. This scoping review outlines AI applications in AIS. METHODS: This study followed PRISMA-ScR guidelines and included articles that reported the development, use, or validation of AI models for treating, diagnosing, or predicting clinical outcomes in AIS. RESULTS: 40 full-text articles were included, with most studies published in the last 5 years (77.5%). Common ML techniques were convolutional neural networks (55%), decision trees and random forests (15%), and artificial neural networks (15%). Most AI applications in AIS were for imaging analysis (25/40; 62.5%), focusing on automatic measurement of Cobb angle, and axial vertebral rotation (13/25; 52%) and curve classification/severity (13/25; 52%). Prediction was the second most common application (15/40; 37.5%), with studies predicting curve progression (9/15; 60%), and Cobb angles (9/15; 60%). Only 15 studies (37.5%) reported clinical implementation guidelines for AI in AIS management. 52.5% of studies reported model accuracy, with an average of 85.4%. CONCLUSION: This review highlights the applications of AI in AIS care, notably including automatic radiographic analysis, curve type classification, prediction of curve progression, and AIS diagnosis. However, the current lack of clear clinical implementation guidelines, model transparency, and external validation of studied models limits clinician trust and the generalizability and applicability of AI in AIS management.

Facet Joint Bridging in Adolescent-onset Adult Idiopathic Scoliosis with Thoracolumbar/Lumbar Curves.

OBJECTIVE: This study aims to comprehend the natural history of Adolescent idiopathic scoliosis (AIS) patients and determine risk factors for facet joint bridging in adolescent-onset adult idiopathic scoliosis with thoracolumbar/lumbar (TL/L) curves. METHODS: We included 50 patients with residual AIS with TL/L curves (3 males, 47 females; age 41.5±17.3 years, TL/L Cobb angle 59.4±11.8°). They were >20 years old and diagnosed with AIS during their adolescence. Radiographic parameters were measured, and facet joint bridging was defined from axial computed tomography (CT) images. RESULTS: The sagittal vertical axis (SVA) significantly increased with age (r=0.71, p<0.01). Coronal Cobb angle of the TL/L curve, L4 tilt, C7 translation, lumbar lordosis (LL), Pelvic incidence (PI) -LL, pelvic tilt (PT), and thoracolumbar kyphosis (TLK) were also correlated to age (p<0.05). There were significant differences in age, SVA, PI-LL, vertebral bridging, facet tropism, and apical vertebral rotation (AVR) between the facet joint bridging group (n=10) and the non-facet joint bridging group (n=40). In the multivariate logistic regression analysis, SVA, vertebral bridging, and AVR emerged as notable risk determinants for facet joint bridging. The threshold for facet joint bridging based on SVA was 2.1 cm (area under the curve [AUC]: 0.801; sensitivity = 90%, specificity = 65%). CONCLUSION: This research revealed that large SVA, the presence of vertebral bridging, and large AVR are associated with facet joint bridging in adolescent-onset adult idiopathic scoliosis patients with TL/L curves. The cut-off value for facet joint bridging based on SVA was 2.1cm.

Associations of overweight status with spinal curve correction and complications in patients undergoing vertebral body tethering: a multicenter retrospective review.

PURPOSE: Our purpose was to determine associations between body mass index (BMI) category and outcomes of vertebral body tethering (VBT), a non-fusion treatment for adolescent idiopathic scoliosis (AIS) and juvenile idiopathic scoliosis (JIS). METHODS: Using a multicenter database, we identified patients with AIS or JIS who underwent VBT from 2012 to 2018 and had minimum 2-year follow-up (median, 3.0 [interquartile range 2.2, 3.8]). BMI percentiles were used to classify patients as overweight (≥ 85th percentile) or non-overweight (< 85th percentile). Univariate and multivariate regressions assessed associations between complication rates and curve correction between groups, controlling for sex, triradiate cartilage closure, and preoperative curve magnitude. RESULTS: Of 271 patients, 48 (18%) were overweight. Complication rates did not differ between groups. Factors associated with less correction from preoperative to first postoperative-erect imaging were overweight (ß = - 10, p < 0.001), male sex (ß = - 8.8 p < 0.01), closed triradiate cartilage (ß = 6.0, p = 0.01), and smaller preoperative curve (ß = 0.3, p < 0.01). Factors associated with a larger curve at latest follow-up were overweight (ß = 4.0, p = 0.02) and larger preoperative curve (ß = 0.5, p < 0.001), but tether breakage did not differ between groups (p = 0.31). CONCLUSION: In patients who were overweight, VBT was associated with less curve correction at first erect imaging and larger final curve. However, complications and curve correction during the modulation phase were not different from those of non-overweight patients. These findings suggest that surgeons should expect less correction with VBT in patients who are overweight but similar correction over time. LEVEL OF EVIDENCE: Prognostic, Level III.

Pulmonary function in patients with idiopathic scoliosis 40 years after diagnosis.

BACKGROUND CONTEXT: Pulmonary function in patients with scoliosis has been a topic of concern, with some reports of markedly decreased ventilatory function leading to disability and increased mortality in patients with severe scoliosis. Only limited data is available concerning pulmonary function in adult patients with scoliosis. PURPOSE: To report the long-term pulmonary function (PF) in patients diagnosed with idiopathic scoliosis (IS) compared with an age-matched population using extended pulmonary function testing (EPFT). STUDY DESIGN/SETTING: Retrospective clinical follow-up. PATIENT SAMPLE: A total of 177 patients seen at our institution from 1972 to 1983 for a pediatric spinal deformity were assessed for inclusion in the study. About 77/129 eligible patients with IS (60%) partook in a clinical examination including radiographs, and EPFT. OUTCOME MEASURES: The EPFT values included forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio, vital capacity (VC), total lung capacity (TLC), residual volume (RV), RV/TLC ratio, diffusion capacity of carbon monoxide (DLco), carbon monoxide transfer coefficient (KCO) and alveolar volume (VA). Results were expressed with z-scores derived from height and arm span normative data. Z-scores were calculated as z-score=Measured PF-Predicted PF /Relative standard deviation (RSD). The limits of normal, are defined as the 5th and 95th percentile limits (z-score between -1.645 and 1.645), respectively. METHODS: Patients underwent a clinical examination with full spine standing radiographs and EFPT. The results were compared between patients with thoracic and thoracolumbar/lumbar (TL/L) main curves, and overall compared with a background population. Results were expressed with z-scores derived from height and arm span normative data. RESULTS: Of 77 included patients, 76 (99%) were females with a mean age of 54.6±2.5 years. The mean follow-up time was 40.8±2.8 years. Forty-four patients had thoracic main curves, and 33 had TL/L main curves. We found no pulmonary impairment based on z-scores in the total cohort or between groups, with only patients who were current or previous smokers, having z-scores below the normal limits Patients with main thoracic curves displayed significantly lower PF on mean absolute values and mean z-scores on FEV1, FVC, FEV1/FVC ratio, VC, TLC, and DLco compared with main TL/L curves. Patients with thoracic curves had significantly larger Cobb angles at follow-up; 52±17° compared with 40±22° (p-value <.05) in the TL/L group. We found no linear association between thoracic Cobb angle and degree of pulmonary impairment assessed with DLco, TLC, and FVC. Comparison of pulmonary z-scores based on arm span data, differed significantly on FVC and TLC, with the arm span measurements showing lower mean z-scores (p-value <.05). CONCLUSIONS: Using EPFT, no pulmonary impairment could be demonstrated compared to the age-matched population 40 years after a diagnosis of IS. However, patients with thoracic curves had decreased PF compared to patients with TL/L curves although within the normal range. Thus, when treated as current guidelines suggest, patients with idiopathic scoliosis can expect the same long-term pulmonary function as the general population.

A Review of 3D Modalities Used for the Diagnosis of Scoliosis.

Spine radiographs in the standing position are the recommended standard for diagnosing idiopathic scoliosis. Though the deformity exists in 3D, its diagnosis is currently carried out with the help of 2D radiographs due to the unavailability of an efficient, low-cost 3D alternative. Computed tomography (CT) and magnetic resonance imaging (MRI) are not suitable in this case, as they are obtained in the supine position. Research on 3D modelling of scoliotic spine began with multiplanar radiographs and later moved on to biplanar radiographs and finally a single radiograph. Nonetheless, modern advances in diagnostic imaging have the potential to preserve image quality and decrease radiation exposure. They include the DIERS formetric scanner system, the EOS imaging system, and ultrasonography. This review article briefly explains the technology behind each of these methods. They are compared with the standard imaging techniques. The DIERS system and ultrasonography are radiation free but have limitations with respect to the quality of the 3D model obtained. There is a need for 3D imaging technology with less or zero radiation exposure and that can produce a quality 3D model for diseases like adolescent idiopathic scoliosis. Accurate 3D models are crucial in clinical practice for diagnosis, planning surgery, patient follow-up examinations, biomechanical applications, and computer-assisted surgery.