Association of success of brace treatment and various aspects of in- brace correction in patients with adolescent idiopathic scoliosis

Background: Although skeletal maturity and brace wear time contribute to the success of brace treatment in adolescent idiopathic scoliosis (AIS), the extent of initial in-brace correction for ensuring successful outcomes remains unclear. We hypothesized that the degree of initial in-brace correction correlates with brace success in patients with AIS.Method: The study included 135 AIS patients with a major Cobb angle of 20(degrees)-40(degrees) treated with a thoracic lumbosacral orthosis for at least one year and followed up for skeletal maturity. The subjects were divided into two groups: the skeletally immature group (group I, n = 72), who met the Bracing in Adolescent Idiopathic Scoliosis Trial study protocol at the start of brace treatment, and the skeletally mature group (group M, n = 63). Treatment success was defined as not needing surgical treatment and a major Cobb angle <40(degrees) at the end of brace treatment.Results: In both groups, the mean major Cobb angles before treatment, while wearing the brace, and at the end of brace treatment were 30.6(degrees)/31.7(degrees), 22.9(degrees)/24.2(degrees), and 38.8(degrees)/33.9(degrees)(p < 0.05), respectively, and the treatment success rate was 56.9% and 77.8%, respectively (p < 0.05). Univariate regression analysis revealed the following risk factors: Risser grade 0 in group I, major Cobb angles before treatment, initial in-brace major Cobb angle, and in-brace correction rate in both groups. Cutoff values of in-brace major Cobb angle for treatment success calculated by ROC curve in groups I and M were 24(degrees) and 29(degrees), respectively.Conclusions: In-brace major scoliosis correction of <25(degrees) in patients with immature skeletal status and <30(degrees) in patients with mature skeletal structure should be aimed at to achieve significant brace treatment success.(c) 2022 Published by Elsevier B.V. on behalf of The Japanese Orthopaedic Association.