Removal of anterior clinoid process for basilar tip aneurysm: Clinical and cadaveric analysis

Abstract

The difficulty in the operation for basilar tip aneurysm is the restriction in surgical working space. To resolve this problem, aggressive skull base surgery has been reported, but these techniques are not prevalent. Pterional and subtemporal approaches are commonly used for basilar tip aneurysms. In an attempt to increase the surgical working space during the pterional approach, the anterior clinoid process and the roof of the optic nerve were removed extradurally to increase the mobilization of the intracranial internal carotid artery and optic nerve. The effects of removing the anterior clinoid process and microanatomy in the perioptic area were analyzed by cadaveric procedures in 10 cases (20 sides). With this procedure, the internal carotid artery can be retracted medially with a spatula 6.1 +/- 0.8 mm (mean +/- SD). The length and the area of dural fold in the bone defect region in the optic canal roof are 2.1 mm and 13.6 mm. In 10 clinical cases, this procedure allowed enough space to approach the basilar tip aneurysm without disturbing the internal carotid artery blood flow. The clinical outcome was satisfactory.

Pre-Operative Measurement of the Morphometry and Angles of the Anterior Clinoid Process (ACP) for Aneurysm Surgery

“…It also enhances mobilization of the intracranial ICA and optic nerve with less brain retraction (Matsuyama et al, 1997;Seoane et al, 1998;Sato et al, 2001). …”

Surgical anatomy of the anterior clinoid process

“…It also increases mobilization of the intracranial ICA and optic nerve with less brain retraction. [11][12][13][14][15] Many reports have described anterior clinoidectomy as part of a more extensive approach. 2-4;6;9;11;16-19 Others have described a few of the anatomical features of the ACP.…”

Morphometric Analysis of the Anterior Clinoid Process of Sphenoid With Its Clinical Implications in Neurosurgeries

“…It also makes the intracranial part of the internal carotid artery and optic nerve mobilization possible with minimal brain retraction [7,[12][13][14]. Several studies on the morphometry of the ACP were concentrated on the length and width of the ACP.…”