Does Curve Regression Occur During Underarm Bracing in Patients with Adolescent Idiopathic Scoliosis?

• Published in: Clinical orthopaedics and related research 2020-02, Vol.478 (2), p.334-345
• Main Authors: Cheung, Jason Pui Yin, Cheung, Prudence Wing Hang, Yeng, Wing Cheung, Chan, Lawrence Chi Kwan
• Format: Article
• Language: English
• Subjects: Adolescent; Age; Axilla; Bone Remodeling; Braces; Child; Clinical Research; Equipment Design; Female; Flexibility; Humans; Male; Menarche; Mental health; Orthopedic Procedures - adverse effects; Orthopedic Procedures - instrumentation; Pain; Patients; Regression analysis; Remission Induction; Retrospective Studies; Scoliosis; Scoliosis - diagnostic imaging; Scoliosis - physiopathology; Scoliosis - therapy; Spine; Spine - diagnostic imaging; Spine - physiopathology; Surgery; Teenagers; Time Factors; Treatment Outcome; Vertebrae; Weaning
• ISSN: 0009-921X; 1528-1132; 1528-1132
• DOI: 10.1097/CORR.0000000000000989

Successful brace treatment entails good control of scoliosis with avoidance of surgery. However, achieving curve regression may be an even better radiological result than prevention of curve progression for patients with adolescent idiopathic scoliosis. Vertebral remodeling may occur with well-fitted braces. Better in-brace curve correction may influence the likelihood of vertebral remodeling and the chance of curve regression. Only a few reports have evaluated curve regression with brace treatment, and the factors associated with these events are unknown. (1) What changes in curvature are observed with brace treatment for adolescent idiopathic scoliosis? (2) What factors are associated with curve improvement? (3) What factors are associated with curve deterioration? (4) Is curve regression associated with improvements in patient-reported objective outcome scores? Between September 2008 and December 2013, 666 patients with adolescent idiopathic scoliosis underwent underarm brace treatment and were followed until skeletal maturity at 18 years old. Among these patients, 80 were excluded because of early discontinuation of brace treatment (n = 66) and loss to follow-up (n = 14). Hence, 586 patients were included in this study, with a mean brace-wear duration of 3.8 ± 1.5 years and post-weaning follow-up duration of 2.0 ± 1.1 years. The mean age at baseline was 12.6 ± 1.2 years. Most patients were female (87%, 507 of 586) and up to 53% (267 of 507) of females were post-menarche. Bracing outcomes were based on changes in the Cobb angle measured out of brace. These included curve regression, as indicated by at least a 5° reduction in the Cobb angle, curve progression, as indicated by at least a 5° increase in the Cobb angle, and unchanged, as indicated by a change in the Cobb angle of less than 5°. We studied the pre-brace and supine Cobb angles, curve flexibility (pre-brace Cobb angle - supine Cobb angle / pre-brace Cobb angle x 100%), correction rate (pre-brace Cobb angle - in-brace Cobb angle / pre-brace Cobb angle x 100%), location of apical vertebrae, apical ratio (convex vertebral height/concave vertebral height), change in the major curve Cobb angle, and apical ratio post-bracing. The refined 22-item Scoliosis Research Society questionnaire was used for patient-reported outcomes and is composed of five domains (function, pain, appearance, mental health and satisfaction with treatment). Its minimum clinically important difference, based on a scale from 0 t