Predictive clinical and radiological factors can potentially identify adolescent idiopathic scoliosis (AIS) most likely to benefit from overcorrection nighttime bracing. These factors can provide helpful information in clinical decision making. However, the relationship between these factors and outcomes of overcorrection nighttime bracing is unclear. This systematic review determined the predictive factors for identifying outcomes of overcorrection nighttime bracing in AIS. A systematic search was conducted on PubMed, MEDLINE, Scopus, and Embase from January 1986 to January 2021. Studies on AIS patients, aged 10–18 years, with a Risser sign of 0–2 and an initial Cobb angle of 20°–45°, who were treated with overcorrection nighttime bracing and for whom at least one predictive factor of treatment outcome (failure and/or success) was assessed were included. Two blinded reviewers independently evaluated the studies using a quality assessment tool. To determine predictive factors, the level of evidence was rated through best-evidence synthesis. A total of nine studies met the inclusion criteria. A Providence brace was used in six of the included studies, while a Charleston bending brace was used in three. Findings from two high-quality studies provided strong evidence of the association between curve flexibility and brace treatment success. In terms of the Risser sign, this evidence was obtained from three high-quality studies. Moderate evidence indicated a positive association between premenarchal status and nighttime bracing failure. Inconclusive evidence indicated that poor brace compliance is associated with treatment failure. Conflicting evidence of treatment failure was indicated for initial curve magnitude, curve type, in-brace correction, age, Risser sign, curve apex, and sex. These findings show that greater curve flexibility and a higher Risser sign are associated with overcorrection nighttime bracing success.

Routinely, adolescent idiopathic scoliosis (AIS) curves that progress beyond 40° in skeletally immature adolescents require surgery. However, some adolescents with AIS and their parents utterly refuse surgery and insist on wearing a brace. Debate continues regarding the appropriateness of bracing for AIS curves exceeding 40° in patients who have rejected surgical intervention. This systematic review and meta-analysis was conducted to review the literature on the effectiveness of bracing and its predictive factors in largermagnitude AIS curves ≥40°. This study replicated the search strategy used by the PICOS system for formulating study questions, which include consideration of the patient/population (P), intervention (I), comparison (C), outcome (O), and study design (S). The search was conducted up to January 2022 in the following bibliographic online databases only in the English language: PubMed, Google Scholar, Scopus, and Web of Science. Two assessors reviewed the articles for qualification. Eligible studies were assessed for risk of bias at the study level using the Newcastle-Ottawa Scale. The effect size across the studies was determined using standardized mean differences (Cohen’s d) and 95% confidence intervals for the meta-analysis. Among the eight included moderate quality studies, evidence of potential publication bias (p <0.05) for the trials included was found in the Cobb angle outcome. Results obtained through meta-analysis indicated that the effectiveness of bracing in controlling Cobb angle progression in curves ≥40° is significantly positive. Additionally, initial curve severity, Risser stage, in-brace curve correction, curve type, and apical vertebral rotation were considered risk factors associated with brace effectiveness. This systematic review revealed that bracing could alter the normal course of AIS curves ≥40° in patients refusing posterior spinal fusion (PSF). However, the suggested course for patients refusing PSF remains unclear because of the significant heterogeneity in the risk factors associated with bracing failure.