In this study comparing bracing with observation for treatment of adolescent idiopathic scoliosis (including a randomized cohort and a cohort treated according to patient preference), bracing was associated with significantly less progression to a curve requiring surgery.
Adolescent idiopathic scoliosis is characterized by a lateral curvature of the spine with a Cobb angle of more than 10 degrees and vertebral rotation.
• How prevalent is adolescent idiopathic scoliosis and what degree of curvature typically indicates the need for surgery?
Whereas scoliosis develops in approximately 3% of children younger than 16 years of age, only 0.3 to 0.5% have progressive curves requiring treatment. Curves larger than 50 degrees are associated with a high risk of continued worsening throughout adulthood and thus usually indicate the need for surgery. In the United States in 2009, there were more than 3600 admissions for spinal surgery to correct adolescent idiopathic scoliosis, the total costs of which (approximately $514 million) ranked second only to appendicitis among children 10 to 17 years of age.
• What were the results of this study, which compared bracing with observation in adolescents with high-risk idiopathic scoliosis?
In the primary analysis, the rate of treatment success was 72% in the bracing group and 48% in the observation group. With adjustment for the propensity-score quintile and duration of follow-up, the odds ratio for a successful outcome associated with bracing was 1.93 (95% CI, 1.08 to 3.46). In the intention-to-treat analysis, the rate of treatment success was 75% among patients randomly assigned to bracing, as compared with 42% among those randomly assigned to observation (unadjusted odds ratio for successful outcome with bracing, 4.11; 95% CI, 1.85 to 9.16). The number needed to treat in order to prevent one case of curve progression warranting surgery was 3.0 (95% CI, 2.0 to 6.2), and the reduction in relative risk with bracing was 56% (95% CI, 26 to 82).
Morning Report Questions
Q: What was the brace dose-response relationship?
A: The quartile of duration of brace wear was positively associated with the rate of success (P<0.001). The lowest quartile of wear (mean hours per day, 0 to 6.0) was associated with a success rate (41%) similar to that in the observation group in the primary analysis (48%), whereas brace wear for at least 12.9 hours per day was associated with success rates of 90 to 93%.
Q: What percentage of untreated individuals had a successful outcome?
A: The authors note that it is relevant that 48% of the patients in the observation group had a successful outcome, as did 41% of the patients in the bracing group who spent little time actually wearing the brace. The authors suggest that current bracing indications may be too broad, resulting in unnecessary treatment for many patients. It is important to identify patients at high risk for curve progression, who are most likely to benefit from bracing.