Full-time bracing versus hybrid bracing in adolescent idiopathic scoliosis: study protocol for a randomised controlled trial

Background Adolescent idiopathic scoliosis (AIS) is a complex three-dimensional spinal deformity affecting 2–4% of adolescents. During the peripubertal stage, untreated AIS may progress rapidly and lead to adverse outcomes such as back pain and poor body image. Full-time bracing, such as the underarm brace (UAB), is indicated for skeletally immature patients with a Cobb angle greater than 20°. Nighttime lateral bending braces (LBB) aim to achieve overcorrection by positioning the patient in a supine bending position opposite to the curve convexity. Despite bracing, 20–30% of patients experience progression requiring surgery. In-brace correction (IBC) is a key determinant of bracing effectiveness. To enhance IBC, we propose a Hybrid Bracing Protocol (HyBP) combining daytime UAB and nighttime LBB. Objective The objective of this trial is to determine whether the Hybrid Bracing Protocol achieves greater in-brace correction (IBC) compared with the conventional bracing at 3 months and 18 months after brace initiation. This 18-month study represents the first phase, followed by a second phase assessing curve outcomes at brace completion and 2 years post-bracing. Methods This is a prospective, randomised, parallel-group trial comparing the Hybrid Bracing Protocol (HyBP) with conventional bracing for enhancing in-brace correction (IBC). Skeletally immature female patients with adolescent idiopathic scoliosis and a single thoracolumbar or lumbar curve newly prescribed for bracing will be randomly allocated to either the HyBP group or conventional brace group (CB group). Discussion To our knowledge, this will be the randomised trial to evaluate the potential synergistic effect of combining two different bracing designs within a hybrid protocol. If effective, this approach may improve bracing outcome, reduce curve progression, and decrease the need for surgical intervention. Trial registration ClinicalTrials.gov NCT07045337. Registered on July 9, 2025.