Limited Intradural Anterior Petrosectomy for Upper Basilar Aneurysms: A Technical Note

Abstract

The extradural anterior petrosectomy is a widely used skull base approach to the upper petroclival region, basilar trunk, and ventral pons. However, there is significant procedure-related morbidity and a complete petrosectomy is required, as the intradural structures are not in view at the time of drilling. We describe an intradural anterior petrosectomy for aneurysms of the basilar trunk and anterior inferior cerebellar artery with intraoperative photographs and artwork to illustrate the approach. A temporal craniotomy is made at the root of the zygoma and middle fossa floor. After opening dura, the trochlear nerve is identified at the tentorial edge. The tentorium is incised posterior to the trochlear nerve and the incision is carried forward across the cisternal segment of the trigeminal nerve toward V3 and the superior petrosal sinus. The petrous apex is identified and drilled lateral and posterior to V3 with a diamond bur. Intraoperative navigation is useful to confirm its location. Once posterior fossa dura is identified, the superior petrosal sinus may be safely cauterized and divided, connecting the tentorial incision with an incision in the posterior fossa dura, and exposing the upper basilar trunk and its branches. Additional bone is removed only as needed. Two patients underwent successful treatment of a basilar trunk perforator and anterior inferior cerebellar artery aneurysm with a subtemporal approach and tailored intradural petrosectomy. The intradural anterior petrosectomy allows limited drilling of the petrous apex and provides sufficient exposure of upper basilar artery aneurysms.