Sphenopterional Point: Strategic Point for Burr Role Placement in Frontotemporal Craniotomies.

Abstract

Frontotemporal craniotomies are the most commonly performed neurosurgical approaches. We studied the external bony landmarks on the lateral surface of the skull to identify a "strategic" point where both the anterior and middle cranial fossae are exposed simultaneously during frontotemporal craniotomies through a single burr hole placed over the greater wing of the sphenoid bone (sphenopterional point). This study aimed to anatomically define the sphenopterional point via craniometric measurements taken on the lateral surface of the human skull. This study used 100 adult (age >18 years old) human dry crania (200 sides) with the calvaria removed, which were cataloged by gender and age. By using laser transillumination, the sphenopterional point was accurately identified in the temporal fossa. Measurements were taken using easily identifiable bony landmarks. On the basis of these landmarks, the horizontal and vertical distances were established between the sphenopterional point and the frontozygomatic suture. Regardless of gender or the side of the skull, the mean horizontal distance was 21.72 mm (SD, 3.17 mm; range, 14.25 mm-32.58 mm), and the mean vertical distance was 4.76 mm (SD, 1.74 mm; range, 0.00-9.73 mm). Neither the horizontal (right side, P= 0.621; left side, P=0.341) nor the vertical measurements (right side, P= 0.460; left side, P= 0.609) differed significantly between genders. Therefore males and females present, on average, the same vertical and horizontal measurements on both sides. According to our measurements, the sphenopterional point is located, on average, 21.72 mm posterior and 4.76 mm superior from the frontozygomatic suture, over the sphenoidal bone component of the pterion region.