Osseous and vascular anatomical variations within the C1-C2 complex: a radiographical study using computed tomography...

Area of Science:

• Neurosurgery
• Anatomy
• Radiology

Background:

• C1-C2 fixation is limited by the anatomical location of the vertebral artery (VA).
• Understanding atlanto-axial VA variations is critical for surgical safety.
• Computed tomography angiography (CTA) is a key imaging modality.

Purpose of the Study:

• To assess anatomical variations of the atlanto-axial VA using CTA.
• To determine the predictability of VA location based on osseous structures.
• To evaluate the utility of CTA in preoperative planning for C1-C2 fixation.

Main Methods:

• 106 patients (54 male, 52 female; mean age 56) underwent CTA.
• Detailed measurements of osseous and vascular elements of the atlanto-axial complex were performed.
• Analysis included distances, diameters, and angles relevant to screw trajectories.

Main Results:

• Significant variations in optimal C1 and C2 screw trajectories were observed.
• The size of the VA groove or foramen did not reliably predict the exact VA location or size.
• Osseous landmarks are insufficient for precise VA localization.

Conclusions:

• Vertebral artery size, location, and path are not precisely predictable from osseous structures like transverse foramina or VA grooves.
• CTA offers valuable insights into atlanto-axial anatomy.
• CTA should be considered a useful adjunct for preoperative evaluation in select C1-C2 fixation cases.