The role of initial bone mineral status in predicting the early outcome of brace treatment in girls with adolescent idiopathic scoliosis

Abstract

To investigate whether initial bone mineral status acts as a predictor factor in evaluating the early outcome of brace treatment in adolescent idiopathic scoliosis (AIS) girls. Seventy-seven girls with AIS, aged 10 - 15 years old, were included in this study. A standardized bracing protocol was performed in these girls, and the early outcomes of brace treatment were evaluated at over-1-year follow-up. Girls with a progressed scoliosis and those with a non-progressed scoliosis were identified. The associations between the outcome and the indices before bracing, including age, menstrual status, Risser grade, bone mineral density (BMD) status, curve magnitude and curve pattern were assessed using univariate analysis. A multiple Logistic stepwise regression was used to determine the risk factors in curve progression in AIS girls treated with brace treatment. There were 16 girls (21%) with a progressed scoliosis and 61 girls (79%) with a non-progressed scoliosis, respectively. In the girls with a progressed scoliosis, higher ratios of subjects were found with pre-menarchal status (chi(2) = 9.628, P = 0.004), lower Risser grade (chi(2) = 4.565, P = 0.037), main thoracic scoliosis (chi(2) = 4.009, P = 0.045), a larger curve (chi(2) = 1.685, P = 0.194), as well as osteopenia (chi(2) = 3.828, P = 0.050), as compared with those with a non-progressed scoliosis. During brace treatment, besides pre-menarchal status, a larger Cobb angle, and a main thoracic scoliosis, osteopenia (OR = 5.362, P = 0.022) was identified as the risk factor in curve progression in AIS girls, as revealed by the multiple Logistic regression analysis. Osteopenia might be an independent risk factor in the curve progression during brace treatment. The analysis of initial BMD status before bracing may help to predict the outcome of brace treatment.