Characterization of Spheno-occipital Synchondrosis Fusion From Preadolescents to Young Adults Using Age and Cervical Vertebrae Maturation Index

The purpose of this study was to characterize the spheno-occipital synchondrosis fusion (SOSF) from preadolescents to young adults. A total of 630 Korean subjects (308 men, 322 women; age range, 6-18 y) were divided into 26 groups according to sex and age. After 3-dimensional computed tomography (CT) images were reoriented using the Frankfort horizontal (FH) plane, mid-sagittal plane, and frontal plane via ON3D software (3DONS), the cervical vertebrae maturation index (CVMI) and SOSF stages were identified using 6-stage and 5-stage scoring systems, respectively. The distributions of stage in each group were statistically investigated. Women showed early appearance and a short range of onset (CVMI stage 2, SOSF stage 2), middle (CVMI stage 4, SOSF stage 3 and stage 4), and completion (CVMI stage 6, SOSF stage 5), indicating rapid skeletal maturation compared with men. In both males and females, there were strong positive correlations between age and CVMI stage (r(s)=0.902, r(s)=0.890), between age and SOSF stage (r(s)=0.887, r(s)=0.885), and between CVMI and SOSF stages (r(s)=0.955, r(s)=0.964) (all P<0.001). The mean ages at SOSF stage 3 and stage 4 (12.7 similar to 13.9 y in males and 11.0 similar to 12.5 y in females) could be used as indicators of the pubertal growth peak. Regression equations for SOSF stage (y), age (a), and CVMI stage (b) were as follows: y=1.355-(0.133xa)+(0.29007xb)+(0.041xaxb) for males (r(2)=0.9496); y=1.305-(0.158xa)+(0.455xb)+(0.036xaxb) for females (r(2)=0.9606). Ordinal logistic regression analyses with the proportional odds model showed that females had more advanced SOSF stages than males (odds ratio: 1.972; 95% CI: 1.063-3.658, P<0.05). Our findings may provide basic references for CVMI and SOSF from preadolescents to young adults.