Radiographic Analysis of the Vidian Canal and Its Utility in Petrous Internal Carotid Artery Localization

BACKGROUND

Endoscopic endonasal surgery of the skull base requires expert knowledge of the anatomy and a systematic approach. The vidian canal is regarded as a reliable landmark to localize the petrous internal carotid artery (pICA) near the second genu, which can be used for orientation in deep skull base approaches. There is controversy about the relationship between the vidian canal and the pICA.

OBJECTIVE

To further establish the vertical relationship between the vidian canal and the pICA to aid in surgical approaches to the skull base.

METHODS

We utilized a collection of institutional review board-approved computed tomographic (CT) angiograms (CTAs). Fifty CTAs were studied bilaterally for 100 total sides. The vidian canal was visualized radiographically to determine whether it terminates below, at, or above the level of the pICA.

RESULTS

Sixty-six of 100 vidian canals terminated inferior to the pICA (66%), which was the most common relationship observed. The average distance inferior to the pICA was 1.01 mm on the right, 1.18 mm on the left, and 1.09 mm of the total 66 sides. Less commonly, the vidian canal terminated at the level of the pICA canal in 34 sides (34%). The vidian canal was not observed to terminate superior to the pICA in any of the 50 CTAs studied.

CONCLUSION

The vidian canal terminates inferior to the pICA most commonly, but often terminates at the level of the pICA. Careful drilling clockwise inferior to superior around the vidian canal should allow for safe pICA localization in most cases.

Imaging in Endoscopic Cranial Skull Base and Pituitary Surgery

Endoscopic endonasal approaches have widely accepted techniques for managing benign and malignant processes along the entire ventral skull base with similar or better results compared with open procedures, but with lower rates of complication. Managing pathology affecting the skull base can be challenging because of complex anatomy and the proximity of critical neurovascular structures. Postoperative imaging can be challenging, because of surgical alterations of normal anatomy and the now common use of complex reconstruction techniques. Understanding the normal imaging appearance of skull base reconstruction is important for accurate postoperative interpretation and delineation between normal reconstructive tissue and recurrent neoplasm.