Factors influencing the final outcome of brace treatment in adolescent idiopathic scoliosis: A retrospective study

Abstract Description

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Authors (including presenting author) :

Chu CY

Affiliation :

Prosthetic and Orthotic Department, The Duchess of Kent Children's Hospital at Sandy Bay

Introduction :

Adolescent idiopathic scoliosis (AIS), the most common type of scoliosis, affects 2 to 3 % of adolescents with unknown etiology. The 3-dimensional spinal deformity causes appearance dissatisfaction due to visible symptoms such as back humps and imbalanced shoulders. It also gives negative impacts in long term which may further affect patients’ adulthood and old age. As the current only proven non-operative means for AIS management, brace treatment aims to prevent scoliotic curve progression during adolescence growth. Although the effectiveness of brace treatment has been already proved in numerous studies, bracing failure was observed on a portion of braced patients. The uncertainty in curve progression despite diligent bracing makes discouragement and frustration to patients and their families. More accurate prediction of bracing outcome is useful to reduce overtreatment and give guidance to clinicians for treatment plan adjustment. It gives patients stronger motivation to continue bracing or improve the brace wearing compliance. If a practical, reliable, cost and time-effective way to predict the brace outcome in early bracing stage can be developed, it can serve as a useful clinical tool for AIS management planning.

Objectives :

This study aims to determine significant factors which would influence the final bracing outcome of patients with adolescent idiopathic scoliosis and to evaluate the treatment outcome with underarm brace.

Methodology :

A retrospective review was conducted for 372 AIS patients who were treated with underarm brace in The Duchess of Kent Children’s Hospital at Sandy Bay between 2009 and 2011. 9 baseline clinical and radiological parameters being measured and recorded in the initial clinical visit for assessment and the first follow-up after brace fitting were investigated, including chronological age, BMI, Risser stage, menarchal status, major curve magnitude, curve type, trunk rotation angle, supine major curve magnitude and initial correction rate. Based on the final outcome of brace treatment, patients were divided into two groups: progressed group and non-progressed group. Comparisons were done among these two groups in terms of the mentioned 9 predictor variables using univariate analysis; and the significant variables were considered as potential predictors in multivariate logistic regression analysis, so as to determine the significant predictive factors for brace treatment outcome.

Result & Outcome :

For a total of 372 patients being included in the analysis, mean age was 12.5 years (SD=1.2) and mean initial Cobb angle was 31.0°(SD=3.7°). 144(39%) patients were observed to have curve progression at skeletal maturity. 37(10%) patients had been operated. Out of the 9 investigated predictor variables, initial univariate analysis showed chronological age, Risser stage, menarchal status, curve type, supine major curve magnitude and initial correction rate significant predictors for curve progression. A multivariate analysis for variables that were significant in the univariate analysis was also performed. The logistic regression model found menarchal status, supine major curve magnitude and initial correction rate were significantly associated with bracing failure/success with odds ratios of 6.85 (95% CI: 3.29-14.29; p< 0.001), 1.14 (95% CI: 1.07-1.21; p< 0.001) and 0.96 (95% CI: 0.94-0.98; p< 0.001) respectively. Overall, 61% of AIS patients treated with underarm brace demonstrated improved or stable curve at the final follow up. Patients with premenarchal status, larger supine Cobb angle and lower initial correction rate at the beginning of brace treatment would have significantly higher risk of curve progression.