Relative anterior spinal overgrowth in mild and moderate adolescent idiopathic scoliosis: A retrospective study

Abstract

Abstract Study design Retrospective study Objective To determine whether the phenomenon of relative anterior spinal overgrowth (RASO) can occur regardless of scoliotic segments and scoliosis severity, and to clarify the regularity of vertebral body height changes in adolescent idiopathic scoliosis (AIS) patients. Methods In total, 125 patients with AIS and 179 non-scoliotic adolescents were recruited for this study. The anterior vertebral body height (VBHa) and posterior vertebral body height (VBHp) were measured on lateral spine radiographs, and the VBHa/VBHp ratio was calculated. The ratios at the same levels between the two groups and different levels within the two groups were compared, as were the ratios among different segmental scolioses in the AIS group. The correlation between scoliosis severity and the ratio of the different vertebrae was subsequently analyzed. Results Between T6 and L5, the VBHa/VBHp ratios were consistently higher in the AIS group than in the control group (P<0.001). Increasing trends were observed for the ratios of T7 to T10 and L1 to L5. There were no statistically significant differences among the ratios for different segmental scolioses at all levels. The Pearson coefficient for the analysis of the correlation between scoliosis severity and VBHa/VBHp ratios showed statistically significant positive correlations with T7 (P<0.05), T8 (P<0.05), and T11 (P<0.05), and negative correlations with L5 (P<0.05). Conclusion The present study confirmed that RASO in patients with mild to moderate AIS is a generalized phenomenon regardless of the scoliosis severity and scoliotic segments. We speculate that the overgrowth on each vertebra is coordinated to maintain the integration of different vertebrae so that the spinal and truncal functions in patients with AIS can be maintained to the greatest extent possible.