Factors relating to curve progression in female patients with adolescent idiopathic scoliosis treated with a brace

Factors Influencing Optimal Bracing Compliance in Adolescent Idiopathic Scoliosis: A Single-center Prospective Cohort Study

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To identify factors contributing to optimal bracing compliance in adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Poor brace compliance is a key factor affecting brace treatment success in AIS. Predictive factors influencing optimal brace compliance to achieve brace treatment success remain unknown.

MATERIALS AND METHODS

This study included AIS patients aged 10 to 15, with a Cobb angle of 20° to 40°. Demographics data, radiographic assessments, and patient-reported outcomes (including the SRS-22r patient questionnaire) were collected. Brace compliance was monitored using in-brace thermometers, defining optimal bracing time as >18 h/d. Multivariable logistic regression analysis was used to identify predictors of optimal bracing time from the demographic and patient-reported outcomes score before bracing.

RESULTS

Among 122 patients, 59.0% achieved optimal bracing time by six months. The achieved group indicated higher scores in the satisfaction domain before bracing (3.3±0.7 vs. 3.1±0.6; P =0.034). Multivariable logistic regression analysis demonstrated that the satisfaction domain before bracing was an independent factor associated with the achievement of the optimal bracing time [OR 1.97 (95% CI: 1.00-3.89), P =0.049]. The model with bracing at one-month follow-up also demonstrated the bracing at 1 month was a significant factor [OR 1.52 (95% CI: 1.30-1.79), P <0.001].

CONCLUSIONS

Optimal bracing compliance in AIS is significantly influenced by prebracing satisfaction and brace compliance at earlier time points. These findings highlight the need to address psychological factors and early compliance in AIS bracing treatment. SRS-22r can be useful to identify the need for psychological support.

The effect of stretching exercises before orthotic treatment on the immediate in-orthosis correction of the patients with adolescent idiopathic scoliosis: A pilot study

BACKGROUND

Stretching exercise is generally used for improving flexibility. However, its application to promote orthotic treatment for patients with adolescent idiopathic scoliosis (AIS) remains unknown.

OBJECTIVE

This study was to explore the effect of pre-orthosis stretching exercises on spinal flexibility and initial in-orthosis correction for the patients with AIS.

STUDY DESIGN

A pilot-controlled study.

METHODS

An experimental group (EG) of 13 subjects (10 girls and 3 boys) with AIS allocating to self-stretching exercises and a control group (CG) of 19 AIS subjects (14 girls and 5 boys) with no stretching before orthosis fitting were recruited. The spinal flexibility of the EG was evaluated with an ultrasound imaging system and physical measurements. The initial in-orthosis correction rates between the 2 groups were compared with the independent t test, and the correlation analysis between the spinal flexibility measured from ultrasound images and physical measurement was performed with the Pearson correlation test.

RESULTS

The initial Cobb angle of EG and CG were 25.70° ± 7.30° and 28.09° ± 5.58°, respectively. No significant difference was observed between the initial in-orthosis Cobb angle of EG (11.13° ± 6.80°) and CG (15.65° ± 9.10°) (p = 0.06). However, the spinal flexibility after stretching exercises was improved (p < 0.001), and the spinal flexibility changes measured with ultrasound and physical forward-bending method were significantly correlated (r = 0.57, p < 0.05).

CONCLUSION

Stretching exercises before orthotic treatment could improve the spinal flexibility but did not cause a better in-orthosis correction. A study with a larger sample size and longer follow-up period should be conducted to investigate the long-term effect of stretching exercises.

Incidence of vitamin D deficiency in adolescent idiopathic scoliosis: a meta-analysis

Introduction

This study aimed to investigate the incidence of vitamin D deficiency in patients with adolescent idiopathic scoliosis through a meta-analysis and to analyze trends and risk factors.

Methods

Potentially relevant studies were searched using the terms "Vitamin D AND scoliosis." Data on the incidence and risk factors, such as race, curve magnitude, and sex, were extracted from the selected studies. Review Manager 5.4 software was used for the data analysis. Six studies with a total of 1, 428 patients met the inclusion criteria.

Results

The incidence of vitamin D insufficiency in patients with idiopathic scoliosis was 36.19% (95% CI [21.93 to 50.46]. In contrast, the incidence of vitamin D deficiency was 41.43% (95% CI [16.62 66.23]. Vitamin D levels were compared between Caucasian and African patients and it was concluded that Caucasian patients had a lower risk of vitamin D deficiency [RR 0.15, 95% CI (0.03 to 0.82; P = 0.03]. There was also an association between patients with idiopathic scoliosis and lower vitamin D -5.58, 95% CI [-7.10, -4.06]. Finally, no significant differences were observed in terms of curve magnitude assessed with the Cobb angle mean difference (MD) 4.45, 95% CI [-0.55, 9.44], or sex with lower-than-normal levels of vitamin D OR 0.96, 95% CI [0.58 to 1.60].

Discussion

The incidence rates of vitamin D insufficiency and deficiency in patients with adolescent idiopathic scoliosis were 36.19% and 41.43%, respectively. The Caucasian race was associated with a lower risk of vitamin D deficiency compared to the African race. Vitamin D deficiency was not related to curve magnitude or sex.

Three-dimensional ultrasonography could be a potential non-ionizing tool to evaluate vertebral rotation of subjects with adolescent idiopathic scoliosis

Background

Three-dimensional (3D) ultrasonography is nonionizing and has been demonstrated to be a reliable tool for scoliosis assessment, including coronal and sagittal curvatures. It shows a great potential for axial vertebral rotation (AVR) evaluation, yet its validity and reliability need to be further demonstrated.

Materials and Methods

Twenty patients with adolescent idiopathic scoliosis (AIS) (coronal Cobb: 26.6 ± 9.1°) received 3D ultrasound scan for twice, 10 were scanned by the same operator, and the other 10 by different operators. EOS Bi-planar x-rays and 3D scan were conducted on another 29 patients on the same day. Two experienced 3D ultrasonographic researchers, with different experiences on AVR measurement, evaluated the 3D ultrasonographic AVR of the 29 patients (55 curves; coronal Cobb angle: 26.9 ± 11.3°). The gold standard AVR was determined from the 3D reconstruction of coronal and sagittal EOS radiographs. Intra-class correlation coefficients (ICCs), mean absolute difference (MAD), standard error measurements (SEM), and Bland-Altman's bias were reported to evaluate the intra-operator and inter-operator/rater reliabilities of 3D ultrasonography. The reliability of 3D ultrasonographic AVR measurements was further validated using inter-method with that of EOS.

Results

ICCs for intra-operator and inter-operator/rater reliability assessment were all greater than 0.95. MAD, SEM, and bias for the 3D ultrasonographic AVRs were no more than 2.2°, 2.0°, and 0.5°, respectively. AVRs between both modalities were strongly correlated (R 2 = 0.901) and not significantly different (p = 0.205). Bland-Altman plot also shows that the bias was less than 1°, with no proportional bias between the difference and mean of expected and radiographic Cobb angles.

Conclusion

This study demonstrates that 3D ultrasonography is valid and reliable to evaluate AVR in AIS patients. 3D ultrasonography can be a potential tool for screening and following up subjects with AIS and evaluating the effectiveness of nonsurgical treatments.

Alternate In-Brace and Out-of-Brace Radiographs Are Recommended to Assess Brace Fitting and Curve Progression With Adolescent Idiopathic Scoliosis Follow-Up

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To determine the prevalence of missed curve progression in patients with adolescent idiopathic scoliosis (AIS) undergoing brace treatment with only in-brace follow-up radiographs, and to provide recommendations on when in-brace and out-of-brace should be obtained during follow-up.

METHODS

133 patients who had documented clinically significant curve progression during brace treatment or only when an out-of-brace radiograph were studied. Of these, 95 patients (71.4%) had curve progression noted on in-brace radiographs while 38 patients (28.6%) showed curve progression only after brace removal. We analyzed differences in age, sex, curve types, Risser stage, months after menarche, standing out-of-brace Cobb angle, correction rate, and flexibility rate between the groups. Multivariate logistic regression was performed to determine factors contributing to curve progression missed during brace treatment.

RESULTS

There were no differences in initial Cobb angle between out-of-brace and in-brace deterioration groups. However, the correction rate was higher (32.7% vs 25.0%; P = .004) in the in-brace deterioration group as compared to the out-of-brace deterioration group. A lower correction rate was more likely to result in out-of-brace deterioration (OR 0.970; P = .019). For thoracic curves, higher flexibility in the curves was more likely to result in out-of-brace deterioration (OR 1.055; P = .045). For double/triple curves, patients with in-brace deterioration had higher correction rate (OR 0.944; P = .034).

CONCLUSIONS

Patients may develop curve progression despite good correction on in-brace radiographs. Those with higher flexibility and suboptimal brace fitting are at-risk. In-brace and out-of-brace radiographs should be taken alternately for brace treatment follow-up.

Predictors of Clinically Meaningful Results of Bracing in a Large Cohort of Adolescents with Idiopathic Scoliosis Reaching the End of Conservative Treatment

BACKGROUND

We need good outcome predictors to maximize the treatment efficiency of adolescents with idiopathic scoliosis (AIS). The in-brace correction has shown an important predictive effect on brace failure, while the influence of other variables is still debated. We aimed to identify new outcome predictors from a big prospective database of AIS.

METHODS

Design: Retrospective analysis of prospectively collected data.

INCLUSION CRITERIA

AIS between 21 and 45°, Risser 0-2, brace prescription during the observation, treatment conclusion. All of the participants followed a personalized conservative approach according to the SOSORT Guidelines.

OUTCOMES

End of growth below 30°-40°-50°. The regression model included age, BMI, Cobb angle, ATR, TRACE score, real brace wear (RBW), and in-brace correction (IBC).

RESULTS

A total of 1050 patients, 84% females, ages 12.1 ± 1.1, 28.2 ± 7.9° Cobb. IBC increased by 30%, 24%, and 23% the odds of ending treatment below 30°, 40°, and 50°, respectively. The OR did not change after the covariate adjustment. Cobb angle and ATR at the start also showed a predictive effect.

CONCLUSIONS

The systematic evaluation of IBC in clinics is useful for individuating the patient response to brace treatment more accurately, even in relation to the Cobb angle and ATR degrees at the start. Further studies are needed to increase the knowledge on predictors of AIS treatment results.

Outcome of Conservative Therapy of Adolescent Idiopathic Scoliosis (AIS) with Chêneau-Brace

Chêneau-brace (C-Brace) is a potential tool for the treatment of adolescent idiopathic scoliosis (AIS) with a Cobb angle between 20° and 45° for the primary curve. The aim of the present study was (1) to estimate study cohorts with C-brace therapy success and therapy failure and (2) to analyze possible factors that influence the therapy outcome. Seventy-eight patients with AIS were assessed before the initiation of C-brace treatment. Each patient underwent radiography examinations before the brace, in-brace, and at the therapy end. Cobb angle was considered as increased when the value at the end of therapy was increased more than 5° (Δ > 5°), unchanged—when the value was unchanged within ± 5° and decreased- when the value was decreased more than 5° (Δ < −5°). The study cohort was stratified due to curve topography in the thoracic, thoracolumbar, and lumbar scoliosis groups. Global analysis revealed no statistically significant modification of the Cobb angle (Cobb angle pre-brace vs. Cobb angle post-brace: 30.8° ± 8.2 vs. 29.3° ± 15.2, p = 0.26). However, at the end of C-brace therapy, the primary Cobb angle was decreased by more than 5° in 27 patients (35%), unchanged (Δ within the range of ±5°) in 36 patients (46%), and increased more than 5° in 15 patients (19%). Sub-group analysis due to curve topography and skeletal maturity has shown higher rates of brace therapy failure in thoracic curves and in younger patients (Risser grade 0). Patients with higher Cobb angle correction with C-brace had lower rates of therapy failure. The C-brace can be useful for the prevention of scoliotic curve progression in patients with AIS. However, many factors influence the therapy effect.

Curve type, flexibility, correction, and rotation are predictors of curve progression in patients with adolescent idiopathic scoliosis undergoing conservative treatment : a systematic review

AIMS

The aim of this study was to review the current evidence surrounding curve type and morphology on curve progression risk in adolescent idiopathic scoliosis (AIS).

METHODS

A comprehensive search was conducted by two independent reviewers on PubMed, Embase, Medline, and Web of Science to obtain all published information on morphological predictors of AIS progression. Search items included 'adolescent idiopathic scoliosis', 'progression', and 'imaging'. The inclusion and exclusion criteria were carefully defined. Risk of bias of studies was assessed with the Quality in Prognostic Studies tool, and level of evidence for each predictor was rated with the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. In all, 6,286 publications were identified with 3,598 being subjected to secondary scrutiny. Ultimately, 26 publications (25 datasets) were included in this review.

RESULTS

For unbraced patients, high and moderate evidence was found for Cobb angle and curve type as predictors, respectively. Initial Cobb angle > 25° and thoracic curves were predictive of curve progression. For braced patients, flexibility < 28% and limited in-brace correction were factors predictive of progression with high and moderate evidence, respectively. Thoracic curves, high apical vertebral rotation, large rib vertebra angle difference, small rib vertebra angle on the convex side, and low pelvic tilt had weak evidence as predictors of curve progression.

CONCLUSION

For curve progression, strong and consistent evidence is found for Cobb angle, curve type, flexibility, and correction rate. Cobb angle > 25° and flexibility < 28% are found to be important thresholds to guide clinical prognostication. Despite the low evidence, apical vertebral rotation, rib morphology, and pelvic tilt may be promising factors. Cite this article: Bone Joint J 2022;104-B(4):424-432.

In-Brace versus Out-of-Brace Protocol for Radiographic Follow-Up of Patients with Idiopathic Scoliosis: A Retrospective Study

The purpose of this retrospective study was to compare two standardized protocols for radiological follow-up (in-brace versus out-of-brace radiographs) to study the rate of curve progression over time in surgically treated idiopathic scoliosis (IS) patients after failed brace treatment. In-brace radiographs have the advantage that proper fit of the brace and in-brace correction can be evaluated. However, detection of progression might theoretically be more difficult. Fifty-one IS patients that underwent surgical treatment after failed brace treatment were included. For 25 patients, follow-up radiographs were taken in-brace. For the other 26 patients, brace treatment was temporarily stopped before out-of-brace follow-up radiographs were taken. Both groups showed significant curve progression compared to baseline after a mean follow-up period of 3.4 years. The protocol with in-brace radiographs was noninferior regarding curve progression rate over time. The estimated monthly Cobb angle progression based on the mixed-effect model was 0.5 degrees in both groups. No interaction effect was found for time, and patients’ baseline Cobb angle (p = 0.98), and for time and patients’ initial in-brace correction (p = 0.32). The results of this study indicate that with both in-brace and out-of-brace protocols for radiographic follow-up, a similar rate of curve progression can be expected over time in IS patients with failed brace treatment.

The Effect of Brace Treatment on Large Curves of 40° to 55° in Adolescents With Idiopathic Scoliosis Who Have Avoided Surgery: A Retrospective Cohort Study

Objective

To evaluate the effect of Milwaukee brace treatment on adolescents with idiopathic scoliosis (AIS) with large curves (40° to 55°) who refuse to do surgery.

Methods

In this retrospective cohort study, we gathered the clinical records of all adolescents with AIS with an initial curve of 40° to 55°. They had been referred to our center from December 1990 to January 2017. Although they had been advised to do surgery, they had all refused to do it. Their clinical data were recorded, such as sex, age, Risser sign, scoliosis, and kyphosis curve magnitude (at the beginning of brace treatment, weaning time, brace discontinuation, and minimum of 2 years after the treatment). Based on treatment success, the patients were divided into 2 groups: progressed and nonprogressed.

Results

Sixty patients with an average initial Cobb angle of 44.93°±4.86° were included. The curve progressed in 57%, stabilized in 25%, and improved in 18% of the patients. In the progressed group (34 patients), 31 patients had undergone surgery. There was no significant association between the age of beginning the brace treatment and the final Cobb angle of nonprogressed group (p>0.05). However, in-brace correction and initial Risser sign had a significant correlation with curve magnitude at the final follow-up (p<0.05).

Conclusion

Brace treatment seems to be effective in controlling the further curve progression in AIS with 40° and 55° curves. Our results can help physicians make sound decisions about the patients with larger curves who refuse to do surgery.

It is not just about the frontal plane: sagittal parameters impact curve progression in AIS patients undergoing brace treatment

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The purpose of this study was to explore the association between pre-brace and in-brace sagittal parameters and curve progression. To date, there has been no published research focused on spinopelvic sagittal parameters and bracing outcomes in AIS. We hypothesize that sagittal spinopelvic parameters are associated with curve progression at 2 years.

METHODS

This study included AIS patients with a pre-brace (PB) major curve between 20° and 45°. The outcome was defined as > 10° curve progression or surgery within 2 years of brace initiation. Spinopelvic parameters included C7-Central Sacral Vertebral Line shift (C7-CSVL), thoracic trunk shift, lumbar lordosis (LL), pelvic incidence (PI), T2-T12 thoracic kyphosis (TK) pelvic incidence-lumbar lordosis (PI-LL) mismatch, sagittal vertical axis (SVA), and pelvic tilt (PT).

RESULTS

Of 50 patients included in this review, [70% Rigo (RCSO) and 30% Boston (BSO)], 16 (32%) patients demonstrated progression (23% of patients with RCSO vs 53% with BSO; p = 0.034). In patients with more than 30% major coronal curve correction (CCC), 23% had progression. 45% of patients progressed when they achieved ≤ 30% correction (p = 0.108). Among PB sagittal parameters and adjusting for coronal curve, patients with an abnormal PB SVA had 3.1 times increased risk of treatment failure compared with patients who had a normal PB SVA. Patients with PB hypo-LL had a 2.8 times increased risk of treatment failure compared with patients who had normal or hyper-LL. Among IB sagittal parameters, patients who had a normal PB PI-LL had a 3.9 times increased risk of treatment failure when they became mismatched in-brace (IB). Patients who had normal pre-brace kyphosis who became hypo-kyphotic IB had an 8.4 times increased risk of treatment failure compared with patients who maintained normal TK or became hyper-kyphotic.

CONCLUSION

These data suggest that we should pay careful attention to sagittal parameters prior to and during brace treatment as braces can control these parameters.

LEVEL OF EVIDENCE

Level III.

Brace treatment in adolescent idiopathic scoliosis: risk factors for failure-a literature review

Brace treatment is the most common nonoperative treatment for the prevention of curve progression in adolescent idiopathic scoliosis. The success reported in level 1 and 2 clinical trials is approximately 75%. The aim of this review was to identify the main risk factors that significantly reduce success rate of brace treatment. A literature search using the MEDLINE and Embase databases was conducted. Studies were included if they identified specific risk factor(s) for curve progression. Studies that looked at nighttime braces, superiority of one type of brace over another, the effect of physical therapy on brace performance, cadaver or nonhuman studies were excluded. A total of 1,022 articles were identified of which 25 met all of the inclusion criteria. Seven risk factors were identified: Poor brace compliance (eight studies), lack of skeletal maturity (six studies), Cobb angle over a certain threshold (six studies), poor in-brace correction (three studies), vertebral rotation (four studies), osteopenia (two studies), and thoracic curve type (two studies). Three risk factors were highly repeated in the literature which identified specific subgroups of patients who have a much higher risk to fail brace treatment and to progress to fusion. This data demonstrates that 60% to 70% of the patients referred to bracing are Risser 0 and 30% to 70% of this group will not wear the brace enough to ensure treatment efficacy. Furthermore, Risser 0 patients who reach the accelerated growth phase with a curve ≥40° are at 70% to 100% risk of curve progression to the fusion surgical threshold despite proper brace wear. Skeletally immature patients with relatively large magnitude scoliosis who are noncompliant are at a higher risk of failing brace treatment.

Bracing In The Treatment Of Adolescent Idiopathic Scoliosis: Evidence To Date

Brace effectiveness for adolescent idiopathic scoliosis was controversial until recent studies provided high quality of evidence that bracing can decrease likelihood of progression and need for operative treatment. Very low evidence exists regarding bracing over 40^ο and adult degenerative scoliosis. Initial in-brace correction and compliance seem to be the most important predictive factors for successful treatment outcome. However, the amount of correction and adherence to wearing hours have not been established yet. Moderate evidence suggests that thoracic and double curves, and curves over 30^ο at an early growth stage have more risk for failure. High and low body mass index scores are also associated with low successful rates. CAD/CAM braces have shown better initial correction and are more comfortable than conventional plaster cast braces. For a curve at high risk of progression, rigid and day-time braces are significantly more effective than soft or night-time braces. No safe conclusion on effectiveness can be drawn while comparing symmetrical and asymmetrical brace designs. The addition of physiotherapeutic scoliosis-specific exercises in brace treatment can provide better outcomes and is recommended, when possible. Despite the growing evidence for brace effectiveness, there is still an imperative need for future high methodological quality studies to be conducted.

[Correlation analysis between interleukin 6 polymorphism and adolescent idiopathic scoliosis susceptibility and bracing effectiveness]

Objective

To analyze the correlation between the polymorphism on interleukin 6 (IL-6) gene promoter region-174 locus and adolescent idiopathic scoliosis (AIS), including the susceptibility, the bracing effectiveness, and the possible mechanism.

Methods

The 182 AIS patients and 210 healthy controls who met the inclusion criteria between January 2013 and January 2016 were collected as research objects. The genotype of IL-6 gene promoter region-174 locus, the serum IL-6, the bone mineral density (BMD) of femoral neck and vertebrae (L _1-4), and the bone metabolism parameters, including bone alkaline phosphatase (BALP), bone gla protein (BGP), tartrate resistant acid phosphatase 5b (TRACP-5b), urine Ca, and urine Ca/Cr, were detected. All research objects were divided into the AIS group and the control group according to whether they had AIS, the GG, CG, CC groups according to their genotype, and progression-free group and progression group according to the therapeutic effectiveness of 1-year bracing treatment. Statistical analysis for the indexes were conducted respectively.

Results

There were significant differences in AIS history, BMD of femoral neck and lumbar vertebrae between the AIS group and control group ( P<0.05). According to the therapeutic effecitveness of 1-year bracing treatment, 182 AIS patients were divided into progression-free group in 110 cases and progression group in 72 cases. The results of single factor analysis showed that there were significant differences in the genotype and allele distribution of IL-6 gene promoter region-174 locus, BMD of femoral neck and lumbar vertebrae, IL-6, TRACP-5b, urine Ca, and urine Ca/Cr between the progression-free group and progression group ( P<0.05). The results of multivariable analysis showed that the BMD of lumbar vertebrae, TRACP-5b, and urine Ca were the influencing factors of bracing efficacy ( P<0.05). According to the results of genotype detection, all research objects were divided into GG group in 264 cases, CG group in 104 cases, and CC group in 24 cases. The IL-6, TRACP-5b, urine Ca, and urine Ca/Cr of GG type carriers were higher and BMD of femoral neck and lumbar vertebrae were lower when compared with the CG and CC type carriers ( P<0.05). The BMD of lumbar vertebrae of CG type carriers was lower than that of CC type carriers ( P<0.05).

Conclusion

The polymorphism of IL-6 genepromoter region-174 locus wasn't correlated with the AIS susceptibility, but it was correlated (not independently correlated) with the scoliosis progression under bracing treatment, and the risk for G-carried patients was higher. The mechanism may be that the polymorphism affected the IL-6 expression level and eventually affected the BMD of AIS patients through the bone metabolism.

Prognostic Value of Bone Mineral Density on Curve Progression: A Longitudinal Cohort Study of 513 Girls with Adolescent Idiopathic Scoliosis

Osteopenia has been found to occur in about 30% of Adolescent Idiopathic Scoliosis (AIS) patients. This study aimed to investigate its prognostic value on the risk of curve progression to surgical threshold. Newly diagnosed AIS girls (N = 513) with Cobb angle 10°–40° were recruited with follow-up till maturity. Bilateral hips were assessed with dual-energy x-ray absorptiometry (DXA). Distal radius of a subgroup of 90 subjects was further assessed with high-resolution peripheral quantitative computed tomography (HR-pQCT). 55 patients progressed to surgical threshold or underwent spine surgery at the end of follow-up. Cox model with osteopenia status performed significantly better than the model without (p = 0.010). Osteopenic patients had significantly higher risk of surgery (HR2.25, p = 0.011), even after adjustment for menarche status, age and initial Cobb angle. The incremental predictive value of osteopenia was, however, not statistically significant. In the subgroup analysis, cortical bone density was identified as a better marker to improve the sensitivity of the prediction, but requires further larger study to validate this finding. These consistent results of bone density measured at different sites suggest a systemic effect, rather than local effect to the deformed spine, and support to the link of abnormal bone density to the etiopathogenesis in AIS patients.

Relationship between the different torsion-related thoracic deformity parameters of adolescent idiopathic scoliosis

INTRODUCTION

Torsion has recently become essential in curve evaluation, not only to assess the degree of clinical deformity that can influence decision making, but also to predict curve progression. Since torsion cannot be currently measured using plain X-rays, our aim was to study the relationships between the different torsion-related parameters measured on 2D radiographs that can indirectly guide the clinician about the torsion of a given curve.

METHODS

This is a cross-sectional study analyzing prospectively registered data of a consecutive cohort of 113 AIS patients with progressive main thoracic deformity. Demographic data, the Adams test and eight radiographic torsion-related coronal and sagittal deformity parameters [apical vertebral rotation (AVR)-Stokes method, Mehta angle (RVAD), main thoracic Cobb side-bending, T5-T12 kyphosis, T5-T8 kyphosis, T9-T12 kyphosis, kyphotic change and double rib contour sign (rib index)] were correlated between each other and with the main thoracic Cobb angle (MTCobb). Univariate linear regression and multiple linear stepwise regression analyses were performed as well.

RESULTS

The radiographically measurable deformity parameters that best correlated with the MTCobb angle in idiopathic curves were: side-bending, RVAD, AVR and the Adams test. Sagittal variables were correlated the least with MTCobb. Coronal parameters as AVR, RVAD, side-bending and Adam test are highly intercorrelated. Sagittal variables are related between each other but are not directly related to coronal parameters.

CONCLUSIONS

There is a strong relationship between the Cobb angle, curve bending, the Mehta angle and the apical vertebral rotation. Together with the clinical Adams test, these are the most important radiographic torsion-related parameters to measure when assessing scoliosis in 2D.

LEVEL OF EVIDENCE

3.