Bracing for idiopathic scoliosis: how many patients require treatment to prevent one surgery?

BACKGROUND: Although the efficacy of bracing for adolescent idiopathic scoliosis has been debated, recent evidence indicates a strong dose-response effect with respect to preventing curve progression of ≥6°. The purpose of this study was to investigate whether bracing, prescribed with use of current criteria, prevents surgery and how many patients must be treated with bracing to prevent one surgery.

METHODS: Of 126 patients with adolescent idiopathic scoliosis measuring between 25° and 45° and with a Risser sign of ≤2, 100 completed a prospective study in which they were managed with a Boston brace fitted with a heat sensor that measured brace wear. Noncompliant patients were compared both with highly compliant patients and with the entire cohort, with the end point of progression to surgery. The absolute risk reduction (ARR) was calculated and used to calculate the number needed to treat (NNT) to prevent one surgery.

RESULTS: Bracing was not effective in preventing surgery unless the patient was highly compliant with brace wear. For patients who were considered to be highly compliant, based on the hours per day that they wore the brace, the NNT was 3 (95% confidence interval [CI], 2 to 7).

CONCLUSIONS: Within the limitations of a nonrandomized prospective study design, bracing for adolescent idiopathic scoliosis was found to substantially decrease the risk of curve progression to a range requiring surgery when patients were highly compliant with brace wear. Since many patients avoid surgery without wearing a brace, current indications appear to lead to marked overtreatment. Bracing appears to decrease the risk of curve progression to a magnitude requiring surgery, but current bracing indications include many curves that would not have progressed to a magnitude requiring surgery even if the patient had not worn the brace, and overall compliance with brace wear is low. Identifying these lower-risk patients and improving the compliance of those likely to have curve progression could substantially improve bracing results.