J Neurol Surg B Skull Base 2016; 77(03): 199-206
DOI: 10.1055/s-0035-1564590
Original Article
Georg Thieme Verlag KG Stuttgart · New York

One Piece Orbitozygomatic Approach Based on the Sphenoid Ridge Keyhole: Anatomical Study

Toma Spiriev
1   Department of Neurosurgery Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
,
Lars Poulsgaard
1   Department of Neurosurgery Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
,
Kaare Fugleholm
1   Department of Neurosurgery Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
› Author Affiliations
Further Information

Publication History

30 March 2015

28 July 2015

Publication Date:
08 October 2015 (online)

Preview

Abstract

The one-piece orbitozygomatic (OZ) approach is traditionally based on the McCarty keyhole. Here, we present the use of the sphenoid ridge keyhole and its possible advantages as a keyhole for the one-piece OZ approach. Using transillumination technique the osteology of the sphenoid ridge was examined on 20 anatomical dry skull specimens. The results were applied to one-piece OZ approaches performed on freshly frozen cadaver heads. We defined the center of the sphenoid ridge keyhole as a superficial projection on the lateral skull surface of the most anterior and thickest part of the sphenoid ridge. It was located 22 mm (standard deviation [SD], 0.22 mm) from the superior temporal line; 10.7 mm (SD, 0.08 mm) posterior and 7.1 mm (SD, 0.22 mm) inferior to the frontozygomatic suture. The sphenoid ridge burr hole provides exposure of frontal, temporal dura as well as periorbita, which is essential for the later bone cuts. There is direct access to removal of the thickest (sphenoidal) part of the orbital roof, after which the paper-thin (frontal) part of the orbital roof is easily fractured. The sphenoid ridge is an easily identifiable landmark on the lateral skull surface, located below the usual placement of the McCarty keyhole, with comparative exposure.