Factors contributing to bracing success in juvenile idiopathic scoliosis and current limitations : a systematic review and meta-analysis.

Abstract

There is a general lack of guidelines on nonoperative treatment in juvenile idiopathic scoliosis (JIS). This review aims to explore factors determining bracing success in JIS and to identify limitations in current literature. A literature search was conducted according to the PRISMA 2020 guidelines. Data extraction focused on the factors affecting bracing success, including pre-brace curve magnitude in Cobb angle, curve type, pre-brace rib vertebral angle difference, in-brace correction, brace type, brace-wear compliance, the time of brace initiation, and bracing duration. Bracing success is defined as 1) avoidance of corrective surgical intervention (curve exceeding 45° at maturity) and/or 2) major curve Cobb angle of < 5° progression at maturity. Meta-analysis was performed for individual factors. After initial and full-text screening, 16 articles were included in the review. Pooled odds ratio (OR) from eight studies and 560 patients using the threshold of Cobb angle of 30° revealed that patients with pre-brace curve < 30° were associated with bracing success (odds ratio (OR) 3.58; 95% CI 2.26 to 5.65; p < 0.001; I² = 0.08). Major thoracic curves were associated with reduced likelihood of bracing success compared to thoracolumbar/lumbar curves (OR 0.49; 95% CI 0.28 to 0.86; p = 0.010; I² = 0.35). Full-time compliance was significantly associated with bracing success (OR 5.22; 95% CI 2.24 to 12.19; p < 0.001; I² = 0.76). This review identified that a pre-brace major Cobb angle < 30° and full-time compliance of at least 18 to 20 hours/day are prognostic factors favourable for bracing success, while presence of thoracic curves is prognostic for unfavourable brace outcome. Longer bracing duration does not translate to a higher success rate. Clinicians should devise more efforts to modify patient compliance in order to achieve optimal brace outcomes. The general lack of high-quality evidence and heterogeneity of results in existing studies indicates the need for further rigorous research on JIS.