Regional vascular relationships to the foramen ovale: an anatomical study with application to approaches to the external skull base with an emphasis on transcutaneous procedures for the treatment of trigeminal neuralgia.

Object: The foramen ovale and its neighboring vascular structures may be seen via external approaches to the skull base. More commonly, however, transcutaneous approaches to the foramen ovale are performed. Although complications with this latter technique are uncommon, studies of the distances to the surrounding extracranial vascular structures are lacking in the literature. The present study aimed to elucidate such anatomical relationships.

Methods: Twenty adult cadavers (40 sides) underwent dissection of the region surrounding the foramen ovale at the external skull base. Measurements between the external surface of the foramen ovale and surrounding vascular structures were made.

Results: From the nearest aspect of the undersurface of the foramen ovale, the authors found that the mean distances to the middle meningeal artery, maxillary artery, superior bulb of the internal jugular vein, and internal carotid artery at its entrance to and exit from the carotid canal were 3, 19, 20, 9, and 12 mm, respectively. Distances tended to be shorter in females, but this did not reach statistical significance. On the basis of these data, the authors also determined a safe zone while approaching the undersurface of the foramen ovale.

Conclusions: Additional knowledge of the neurovascular relationships surrounding the foramen ovale may be useful to the neurosurgeon and may help decrease the potential for complications.