Pterional craniotomy via a transcavernous approach for the treatment of low-lying distal basilar artery aneurysms.

Abstract

The author describes a surgical procedure in which pterional craniotomy is performed via a transcavernous approach to treat low-lying distal basilar artery (BA) aneurysm. This intradural procedure is compared with the extradural procedure described by Dolene, et al. The addition of a transcavernous exposure to the standard pterional intradural transsylvian approach allows a lower exposure of the distal BA behind the dorsum sellae. The technical steps involved in this procedure are as follows: 1) removal of the anterior clinoid process: 2) entry into the cavernous sinus medial to the third nerve; 3) packing of the venous channels of the cavernous sinus lying between the carotid artery and the pituitary gland to open this space; 4) removal of the posterior clinoid process and the portion of the dorsum sellae that is exposed from within the cavernous sinus; and 5) removal of the exposed dura mater to obtain additional exposure of the peri-mesencephalic cistern. Eight cases of aneurysms of the distal BA are presented to illustrate how this approach can help in their surgical treatment. Using the standard pterional approach, these distal BA aneurysms were found to be either too low relative to the posterior clinoid process for adequate exposure or there was insufficient room for temporary clipping of the BA proximal to the lesion. The addition of a transcavernous exposure eliminated these technical problems and aneurysm clipping could be accomplished in each case.