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

Study design: Retrospective multicenter cohort study.

Objective: 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).

Background: Recent studies have shown that FTB in patients with AIS may induce hypokyphosis. Whether this effect differs between NTB and FTB is unknown.

Materials and methods: 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.

Results: 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).

Conclusion: 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.