Abstract
The indications for early surgery for ruptured basilar artery aneurysms remain controversial, because operative results have not satisfactory enough to date.
Thirty-three cases of ruptured basilar artery aneurysm have been seen during the last 17 years, from 1971 to 1987, in the authors' institute. Twenty-five cases were basilar bifurcation aneurysms and eight were basilar-superior cerebeller aneurysms. Surgical treatment was performed in 19 cases. Only six cases were treated by early operation. Of these, three suffered surgical complications and died. These complications were brain contusion due to severe brain retraction, ischemia or embolism due to direct retraction of the major artery, and injury of perforating arteries. The neck of the aneurysm in these three cases was located in the high portion more than 10 mm above the line between the anterior clinoid process and the posterior clinoid process. The position of the aneurysm seems to be related to the surgical outcome in the basilar artery aneurysm.
Judging from our experience in past surgical cases, the most difficult and important aspect of surgery is achieving a good exposure around the aneurysm through minimal brain retraction, especially in early intervention. For that purpose, the transsylvian approach is considered to be the most effective of several approaches. However, there are some key points to be considered in the transsylvian approach to basilar artery aneurysm, as follows:
1) At craniotomy, the sphenoid wing must be planed sufficiently to get a good exposure. If the aneurysm is located high, either a supraorbital pterional approach or a frontozygomatic approach can provide better exposure.
2) The brain must be shrunken using ventricular drainage and mannitol.
3) The sylvian fissible must be dissected widely.
4) Direct retraction of the major artery must be avoided much as possible except when applying a clip for the aneurysm.
5) The aneurysm must be exposed and dissected not only lateral to the carotid artery but also medial to it.
Recently, several cases have been operated on early following these key points and the result has been a good clinical outcome.
