Association Between Vertebral Cross-sectional Area and Vertebral Wedging in Children and Adolescents: A Cross-sectional Analysis.

A small vertebral cross-sectional area (CSA) imparts a mechanical disadvantage that escalates the risk for vertebral fractures in elderly populations. We examined whether a small vertebral CSA is also associated with a greater degree of vertebral wedging in children. Measurements of vertebral CSA, lumbar lordosis (LL) or thoracic scoliosis angle, and vertebral wedging were obtained in 100 healthy adolescents (50 boys and 50 girls) and 25 girls with adolescent idiopathic scoliosis (AIS) using magnetic resonance imaging. Vertebral CSA of the lumbar vertebrae negatively correlated to the degree of posteroanterior vertebral wedging at L5 (r = -0.49; p < 0.0001); this was true whether all subjects were analyzed together or boys and girls independently. In contrast, we found a positive correlation between the degree of LL and vertebral wedging (r = 0.57; p < 0.0001). Multiple regression analysis showed that the association between vertebral CSA and wedging was independent of age and body mass index. In girls with AIS, vertebral CSA negatively correlated to the degree of lateral thoracic vertebral wedging (r = -0.66; p = 0.0004), an association that persisted even after accounting for age and body mass index. Additionally, Cobb angle positively correlated to lateral thoracic vertebral wedging (r = 0.46; p = 0.021). Our cross-sectional results support the hypothesis that smaller vertebral CSA is associated with greater vertebral deformity during growth, as in adulthood.