Evaluation of the First Cervical Vertebra Anatomy for Screw Fixation.

Aim: To conduct a morphometrical analysis of the atlas to facilitate the development of atlas-related treatment methods and demonstrate the variations in atlas anatomy to aid surgical approaches and reduce complications.

Material and methods: The present study was conducted on 58 dry human atlas vertebrae supplied by the Ege University Faculty of Medicine, Department of Anatomy. Morphometrical analysis was performed using digital calipers.

Results: The quantitative measurements were analyzed for screw fixation. The variations in the atlases were identified as spina bifida (1.7%), accessory foramen (on the right and left sides in 8.6% and 1.7%, respectively), canal for vertebral artery (1.7%, each on the right and left sides, and bilateral in 5.2%), and bipartite superior articular surface (on the right and left sides in 5.2% and 1.7%, respectively).

Conclusion: Some of these anatomical variants may explain certain previously described clinical symptoms. The measurements obtained from the 58 atlas vertebrae and the variations observed during the study were discussed. The primary outcome of the present study was that the measurements of the vertebrae are different for every individual. Therefore, it is important to use imaging methods and examinations before screw placement and other surgical approaches.