Localization of the Foramen Ovale for Treatment of Trigeminal Neuralgia: An Anatomical Perspective

Background: Identification of the foramen ovale by intraoperative x-ray imaging is an essential step for correct placement radiofrequency electrode for treatment of trigeminal neuralgia. Easily identifiable radiological landmarks are necessary for correct localization of the foramen ovale.

Methods: Dry human skulls were studied, and the following measurements were taken. Distances (D) seen in the A-P view—D-1: the transverse distance between the apex of the petrous temporal and the center of the foramen ovale, and D-2: the transverse distance from the midline to the center of the foramen ovale. Distances (D) seen in the lateral view—D-3: the distance between the center of the foramen ovale and the anterior margin of mandibular fossa, D-4: the distance between the center of the foramen ovale and the center of the mandibular fossa, D-5: the point at the junction of posterior margin and floor of the sella, and D-6: the vertical distance between the center of the foramen ovale and a point at the junction of posterior margin and floor of the sella.

Results: The mean values for the various distances measured were D-1: 13.9 mm, D-2: 24.5 mm, D-3: 3.1 mm, D-4: 11.4 mm, D-5: 0.75 mm, and D-6: 12.42 mm.

Conclusion: During intraoperative imaging, the midline of the skull as well as the junction of the posterior wall and floor of the sella can be used as reliable landmarks for the identification of the foramen ovale.