Imaging study of coccygeal morphology in adolescent idiopathic scoliosis

Abstract

Objective To observe the coccygeal morphology in adolescent idiopathic scoliosis (AIS) and the differences among different types of scoliosis. Methods A retrospective analysis was performed on 268 patients who received full-length anteroposterior and lateral spine radiographs in the third affiliated hospital of Zhejiang Chinese Medical University from January 2018 to December 2022. They were divided into normal group with 135 cases and AIS group with 133 cases. Postacchini coccygeal radiological classification method modified by Nathan was used to observe and compare the sagittal plane coccygeal morphology in the two groups. The correlations between coccygeal morphology in sagittal plane and gender, scoliosis severity, scoliotic segments were analyzed too. Results There were the highest percentage (50.4%) of Type I and the lowest (5.2%) proportion of Type V in normal group and the highest percentage (33.1%) of Type I and the lowest (2.2%) proportion of Type V in AIS group. The difference in coccygeal morphology was significant between normal group and AIS group (P = 0.006). There were no significant differences in coccygeal morphology between mild and moderate scoliosis (P = 0.489), between male and female (P = 0.812 in normal group, P = 0.287 in AIS group), or among thoracic, thoracolumbar and lumbar scoliosis (P = 0.129). There was a significant correlation between coccygeal morphology and scoliosis (P = 0.049). Conclusions Coccygeal morphology in mild and moderate AIS patients is significantly different from that in normal adolescents. The proportion of coccygeal type I is significantly higher in normal children than in AIS patients, while the proportion of coccygeal type II and type III is significantly lower in normal children. There were some differences in coccygeal morphology between mild and moderate scoliosis, and among different segmental scoliosis, but they were not significant. There was a significant correlation between coccygeal morphology and scoliosis, but the correlations between coccygeal morphology and gender, scoliosis severity, scoliotic segments were non-significant.