Outcomes for nighttime bracing in adolescent idiopathic scoliosis based on brace wear adherence

Background: This study determined brace wear adherence for patients treated with nighttime braces and evaluated the effect of brace adherence on curve progression. Methods: One hundred twenty-two patients with AIS ages 10–16 years, Risser stages 0–2, major curves 20°–40° treated with Providence nighttime braces prescribed to be worn at least 8 h per night were prospectively enrolled and followed until skeletal maturity or surgery. Brace adherence was measured using iButton temperature sensors after 3 months of brace initiation and at brace discharge. Results: Curve types were single thoracolumbar/lumbar (62%, n = 76), double (36%, n = 44), and single thoracic (2%, n = 2). Brace adherence averaged 7.8 ± 2.3 h after 3 months (98% adherence) and 6.7 ± 2.6 h at brace discharge (84% adherence). Curves that progressed ≥ 6° had decreased brace adherence than non-progressive curves after 3 months (7.0 h vs. 8.1 h, p = 0.010) and at brace discharge (5.9 h vs. 7.1 h, p = 0.017). Multivariate logistic regression analysis showed that increased hours of brace wear [odds ratio (OR) 1.23, 95% confidence interval (CI) 1.06–1.46], single curves (OR 3.11, 95% CI 1.35–7.53), and curves < 25° (OR 2.61, 95% CI 1.12–6.44) were associated with non-progression at brace discharge. Conclusions: Patients treated with nighttime bracing have a high rate of brace adherence. Lack of curve progression is associated with increased brace wear. Nighttime bracing is effective at limiting curve progression in AIS single thoracolumbar/lumbar and double curves. Level of evidence: Prognostic Level 2.