Sexual Dimorphism Of Craniometric Indices Of The Craniovertebral Junction In A Kenyan Population

A Cross Sectional Radiological Study

Abstract

Importance: Craniometric indices are useful in the diagnosis of Craniovertebral Junction (CVJ) lesions and in planning surgical access and resection margins. Objective: To determine the sex differences in morphometric indices of the CVJ. Methods: Cross-sectional survey of 116 patients (equal numbers of males and females) done between August and October 2021 at the Kenyatta National Hospital. Bone window formats of axial CT scans centred on the base of the skull of patients undergoing routine head and neck imaging. The measured variables were the sagittal diameter from the basion to the opsithion and the transverse diameter, the distance of the odontoid tip from the sagittal diameter of the foramen magnum. The derived variables were the foramen magnum index and the area of the foramen. Results: The mean age of the participants was 38 ± 12 years. The mean diameter of the anterior-posterior dimension of the foramen magnum was 35.7±2.88mm, while the transverse diameter was 30.2±2.88mm. The mean distance between the odontoid peg and the anterior-posterior diameter was 6.3 ±2.3 mm, indicating that none of the pegs protruded into the foramen. The mean area of the foramen was 847 ± 83.4 mm2, while the foramen magnum index was 1.19 ± 0.1. The difference in means between males and females was statistically significant for the anterior-posterior diameter, transverse diameter and area (p<0.001). Conclusion: Craniometric indices in this study are comparable to other populations. The predominance of rounded foramens may indicate easier access to lesions with resultant lesser CVJ instability.