Abstract
BACKGROUND: This study aimed to determine the index of the sacral vertebrae fusion period in children and adolescents to diagnose the lesion around the sacral spine accurately. METHODS: Patients aged 0-40 years who underwent computed tomography (CT), including the normal sacrum for screening abdominal disorders and pan-scan in trauma between 2019 and 2022 were retrospectively examined. There were 402 eligible sacra (385 patients: 206 women and 179 men). We evaluated bony fusion at six parts of the sacral vertebrae (anterior or posterior of each intervertebral and both side lateral masses). The predicted probability of bony fusion obtained from the logistic regression model is depicted graphically by sex. RESULTS: The association between bony fusion in each vertebral segment and age was evaluated using a logistic regression model with a Huber-White robust sandwich estimator, including the patient as a clustering variable. Bony fusion of the sacral bodies of S1/S2 was slowest, with 80% of patients achieving bony fusion at 28.7 and 24.6 years of age for men and women, respectively. Compared to men, women exhibited earlier fusion of the intervertebral segments of the sacral vertebrae; however, no significant difference between the sexes in terms of eventual bony fusion at the lateral mass was observed, while the initiation of bony fusion occurred earlier in women. CONCLUSION: The predicted probability of bony fusion could aid pediatricians, orthopedists, radiologists, and other physicians in understanding the normal development of the sacral spine and accurately differentiating the lesion around the sacral spine.