Introduction: Growth rate and pattern of girls with Adolescent idiopathic scoliosis (AIS) are proposed to be related to its occurrence and progression. The cross-sectional nature of previous studies did not allow a comprehensive understanding of the relationship. The current study aimed to use both cross-sectional and longitudinal anthropometric data to elucidate the growth pattern of AIS girls of different severities.
Methodology: 611 AIS and 296 control girls aged between 12 and 16 were recruited. 194 AIS and 116 controls among the recruited subjects participated in the longitudinal study. The AIS girls were further divided into two groups according to their curve severity. Anthropometric parameters were measured at each visit. The differences in all parameters between AIS of different severities and control subjects were analyzed with one-way ANOVA in the cross-sectional study. While the growth patterns in terms of arm span were evaluated by linear mixed model in the longitudinal study.
Results: In the cross-sectional study, severe AIS started with a shorter arm span than moderate AIS and control at age 12 but overtook at age 14-16. For the longitudinal analysis from age 12 to 16, moderate AIS had a longer arm span than control but with similar growth rate. While severe AIS had a higher growth rate than moderate AIS by 71% (p=0.001) and control by 30% (p=0.07) respectively.
Discussion: Growth spurt during puberty is a key factor associated with the etiopathogenesis and curve progression in AIS. The current study showed that AIS of different severities and normal controls had different growth rate between age 12 and 16, revealing its possible association with scoliosis development and progression. The findings corroborated the hypothesis of abnormal skeletal growth in AIS which may contribute to its etiopathogenesis. The measurement of arm span growth could be an important clinical parameter in helping to predict the development of severe scoliosis in AIS.