The spheno-pterional point: a strategic point for burr role placement in frontotemporal craniotomies

• Published in: World neurosurgery
• Main Authors: Reis, Baltazar Leão, MD, Silveira, Roberto Leal da, MD, PhD, Gusmão, Sebastião Nataniel Silva, MD, PhD
• Format: Journal Article
• Language: English
• Published: 2017
• Subjects: Neurosurgery; pterional; keyhole; spheno-pterional point; modified keyhole; frontolateral craniotomy; craniometric points
• ISSN: 1878-8750
• DOI: 10.1016/j.wneu.2017.06.011

Abstract Background 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 sphenoid bone (spheno-pterional point). Objective This study aimed to anatomically define the spheno-pterional point via craniometric measurements taken on the lateral surface of the human skull. Methods This study used one hundred adult (age > 18yo) human dry crania (200 sides) with the calvaria removed, which were cataloged by gender and age. By using laser transillumination, the spheno-pterional point was accurately identified in the temporal fossa. Measurements were taken based on easily identifiable bony landmarks. Based on these landmarks, the horizontal and vertical distances were established between the spheno-pterional point and the frontozygomatic suture. Results Regardless of gender or the side of the skull, the mean horizontal distance was 21.72mm (SD, 3.17mm; range, 14.25mm-32.58mm), and the mean vertical distance was 4.76mm (SD, 1.74mm; range, 0.00-9.73mm). 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. Conclusions According to our measurements, the spheno-pterional point is located, on average, 21.72mm posterior and 4.76mm superior from the frontozygomatic suture, over the sphenoidal bone component of the pterion region.