The Effect of Night-time Versus Full-time Bracing on the Sagittal Profile in Adolescent Idiopathic Scoliosis : A Propensity Score-matched Study.

Abstract

Retrospective multicenter cohort study. To investigate the impact of night-time bracing (NTB) and full-time bracing (FTB) on the sagittal profile in patients with adolescent idiopathic scoliosis (AIS). Recent studies have shown that FTB in patients with AIS may induce hypokyphosis. Whether this effect differs between NTB and FTB is unknown. We included skeletally immature patients with AIS with main curves ranging from 20° to 45° treated with either NTB or FTB. The 2 cohorts were propensity-score matched on Risser stage, age, major curve size, and kyphosis at brace initiation. Coronal and sagittal radiographic parameters were gathered at the initiation and completion of brace treatment. Two hundred fifty-seven patients were eligible for inclusion. The matched cohorts included 62 patients in each group. During bracing, the thoracic kyphosis increased from 31 ± 11° to 35 ± 13° in the NTB group compared with a decrease from 30 ± 12° to 28 ± 13° in the FTB group ( P = 0.011). Of the total, 8% were hypokyphotic (<20°) after bracing in the NTB group compared with 24% in the FTB group ( P = 0.015). Pelvic incidence, sacral slope, and pelvic tilt were not significantly different between the groups. In the coronal plane, curve progression >50° was seen in 50% of the NTB group and 31% in FTB ( P = 0.028). We saw a small increase in thoracic kyphosis in the NTB group versus a small decrease in the FTB group. After bracing, 8% in the NTB group versus 24% in the FTB group showed substantial hypokyphosis. The impact of minor changes in thoracic kyphosis remains uncertain; however, a 3-fold difference in the occurrence of hypokyphosis is notable and merits further attention.