Osseous and vascular anatomical variations within the C1-C2 complex: a radiographical study using computed tomography angiography
Parham Moftakhar1, Nestor R Gonzalez, Larry T Khoo
1Division of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
Insights
The exact location and size of the vertebral artery (VA) in the C1-C2 region cannot be predicted by bone anatomy alone. Computed tomography angiography (CTA) is crucial for surgical planning in atlanto-axial fixation.
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.
Background:
One of the limiting factors of C1-C2 fixation is the location of the vertebral artery (VA). The authors sought to assess the potential variations in atlanto-axial VA anatomy using computed tomography angiography (CTA).
Methods:
Detailed measurements were made on digital images of 106 patients undergoing CTA at our institution (54 males, 52 females; mean age 56, range 20-86). Distances, diameters and angles of osseous and vascular elements of the atlanto-axial complex were measured.
Results:
Optimal C1 and C2 screw trajectories demonstrated wide variations among patients. The size of the VA groove or foramen was not predictive of exact arterial location or size.
Conclusions:
The size, location and path of the VA cannot be precisely predicted by the appearance of osseous structures such as the transverse foramina and/or the VA groove. CTA provides additional information regarding the atlanto-axial complex, and should be considered as a useful adjunct in the preoperative evaluation of select patients.
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