The effect of Providence night-time bracing on the sagittal profile in adolescent idiopathic scoliosis.

PURPOSE: Adolescent idiopathic scoliosis (AIS) is characterized by coronal scoliosis and often a sagittal hypokyphosis. The effect of bracing on the sagittal profile is not well understood. The aim of this study is to assess the effect of night-time bracing on the sagittal profile in patients with AIS. METHODS: We retrospectively included AIS patients with a main curve of 25-45° treated with a night-time brace in our institution between 2005 and 2018. Patients with estimated growth potential based on either Risser stage, hand X-rays, or menarchal status were included. Coronal and sagittal radiographic parameters were recorded at both brace- initiation and -termination. Patients were followed until surgery or one year after brace termination. Results were compared to a published cohort of full-time braced patients. RESULTS: One hundred forty-six patients were included. Maximum thoracic kyphosis (TK) increased 2.5° (± 9.7) (p = 0.003), corresponding to a 3.5-fold relative risk increase post bracing in TK compared to a full-time brace cohort. Twenty-seven percent (n = 36) of the patients were hypokyphotic (T4/T12 < 20°) at brace initiation compared with 19% (n = 26) at brace termination (p = 0.134). All other sagittal parameters remained the same at follow-up. We found no association between progression in the coronal plane and change in sagittal parameters. CONCLUSION: This is the first study to indicate that night-time bracing of AIS does not induce hypokyphosis. We found a small increase in TK, with a substantially lower risk of developing flat back deformity compared to full-time bracing. The coronal curve progression was not coupled to a change in TK.

The influence of night-time bracing on curve progression is not affected by curve magnitude in adolescent idiopathic scoliosis: a study of 299 patients.

BACKGROUND AND PURPOSE: The efficacy of bracing larger curves in adolescent idiopathic scoliosis (AIS) patients is uncertain. We aimed to assess the influence of night-time bracing in AIS patients with main curves exceeding 40° Cobb angle at brace initiation. METHODS: We reviewed AIS patients treated with nighttime braces between 2005 and 2018. Patients with curves ≥ 25° and estimated growth potential were included. Patients were monitored with radiographs from brace initiation until brace weaning at skeletal maturity. Patients were grouped based on curve magnitude at initial evaluation: a control group (25-39°) and a large-curves group (≥ 40°). Progression was defined as > 5° increase. RESULTS: We included 299 patients (control group, n = 125; large-curves group, n = 174). In the control group, 65 (52%) patients progressed compared with 101 (58%) in the large-curves group (P = 0.3). The lower-end vertebra (LEV) shifted distally post-bracing in 41 (23%) patients in the largecurves group. Patients with progressive large curves were younger (age 13.2 [SD 1.5] vs. 13.9 [SD 1.1], P = 0.009) and more premenarchal (n = 36 [42%] vs. n = 6 [9%], P < 0.001) compared with non-progressive large curves. CONCLUSION: Progression risk in patients with curves exceeding 40° treated with night-time bracing is similar to smaller curves. The LEV moved distally in almost one-fourth of the larger curves, possibly affecting fusion levels in cases of surgery.

Does Risser stage accurately predict the risk of curve progression in patients with adolescent idiopathic scoliosis treated with night-time bracing?

PURPOSE: Risser stage is widely used as a marker for skeletal maturity (SM) and thereby an indirect measure for the risk of progression of adolescent idiopathic scoliosis (AIS). The Scoliosis Research Society recommends bracing for Risser stages 0-2 as Risser stage 3 or above is considered low risk. Very few studies have assessed the risk of progression during bracing in Risser stages 3-4. The objective of the current study is to determine if Risser stages 3-4 provide a meaningful cutoff in terms of progression risk in patients with AIS treated with night-time bracing. METHODS: AIS patients treated with night-time brace from 2005 to 2018 with a Cobb angle between 25 and 40 degrees and Risser stages 0-4 were retrospectively included. Curve progression (> 5 degrees increase) was monitored until surgery or SM. Skeletal maturity was defined as either 2 years postmenarchal, no height development or closed ulnar epiphyseal plates on radiographs. RESULTS: One hundred and thirty-five patients were included (Risser stages 0-2: n = 86 and 3-4: n = 49). Overall, radiographic curve progression occurred in 52% while progression beyond 45 degrees was seen in 35%. The progression rate in the Risser 0-2 group was 60% and 37% in the Risser 3-4 group (p = 0.012). In multivariate logistic regression analysis, adjusted for Risser stages and age, only premenarchal status showed a statistically significant association with progression (OR: 2.68, 95%CI 1.08-6.67). CONCLUSION: Risser stage does not provide a clinically meaningful differentiation of progression risk in AIS patients treated with a night-time brace. Risk assessment should include other more reliable measures of skeletal growth potential.