Defining standardized guidelines for brace-weaning in adolescent idiopathic scoliosis

Abstract

Purpose: Current brace weaning guidelines for adolescent idiopathic scoliosis (AIS) are not well-defined. Most consider Risser stage 4, 2-year post-menarche, and lack of height gain as justifiable reasons for brace weaning. However, curve progression is still observed. With more refined and standardized maturity parameters, brace weaning guidelines should be redefined. This study aims to assess the curve progression risk with Risser staging, bone age assessments via Sanders staging (SS), and the distal radius and ulna classification (DRU), as well as to redefine brace weaning criteria. Materials and Methods: Consecutive AIS patients who underwent brace weaning from June 2014 to March 2016 were prospectively recruited and followed up for 2 years after weaning. Patients were referred for brace weaning based on the following criteria: Risser 4, no growth in the past 6 months of follow-up, and post-menarche of at least 2 years. Skeletal maturity was assessed by Risser staging, SS, and DRU. Statistical analyses included inter-group comparison of with/without curve progression, binomial stepwise logistic regression, odds ratio with their 95% confidence intervals, and risk ratio calculation. Results: Patients (N=144) were recruited without dropouts. Up to 29.2% of patients experienced curve progression fter brace weaning despite our standardized weaning criteria. Large curves (≥45°) observed more curve progression (p=0.002) as an independent risk factor. Patients weaned at SS7, radius grade (R) 9, and ulna grade (U) 7 were more likely to experience curve progression (p<0.001). No progression was observed with R11 and U9. The earliest maturity indices with reasonable protective effect were SS8, and R10 with U9. Conclusion: Brace weaning indications using Risser staging is inadequate. Curve progression is expected for large curves irrespective of maturity status due to its disease nature. Bone age measurement by either SS8 or DRU (R10/ U9) provides earliest and clearer guidelines for brace weaning that result in least post-weaning curve progression.