Endoscope-assisted keyhole surgery for aneurysms of the anterior circulation and the basilar apex

Abstract

In the treatment of cerebral aneurysms, preoperative surgical planning and intraoperative strategies for microsurgical approaches are important issues. Within the context of minimally invasive neurosurgery, so-called keyhole approaches, especially those with intraoperative endoscopic assistance, have gained increasing interest, but their application for cerebral aneurysm surgery is a matter of ongoing controversy. The main aspects of keyhole microsurgery, with and without endoscopic assistance, for cerebral aneurysms are explained. To present the keyhole concept, which is based on the preoperative analysis and intraoperative use of pre-existing anatomic windows, this article concentrates on the access to the most frequent aneurysm sites, those of the anterior circulation and of the basilar apex. The basic principles of microsurgical dissection of subarachnoid structures are summarized. If feasible, extensive preoperative diagnostic imaging is used to conduct the most accurate approach planning possible. Procedures are described for single and multiple aneurysms as well as for aneurysms treated through ipsilateral and contralateral approaches. The application of the most frequently used keyhole craniotomies, such as the supraorbital, the subtemporal, and the interhemispheric approach, is depicted. The principles of endoscope-assisted techniques in cerebral aneurysm surgery are elucidated.