The pretemporal transcavernous approach to the interpeduncular and prepontine cisterns: microsurgical anatomy and technique application.

Abstract

To illustrate in a stepwise fashion the microsurgical anatomy of the transcavernous approach to the interpeduncular and prepontine cisterns and to discuss our initial results with 15 basilar tip aneurysms managed through that approach. Using 10 embalmed cadaveric heads perfused with colored silicon, we performed bilateral stepwise dissections of the transcavernous approach via an orbitozygomatic pretemporal craniotomy. Measurements of the exposure of the basilar artery obtained along the dorsum sellae and upper clivus were taken. Our clinical data were derived from a series of 15 patients with large basilar tip aneurysms treated surgically via the transcavernous approach between 1997 and 1999. Indications for surgery were based on the size of the aneurysm (all were large) and its position in relation to the dorsum sellae (eight were more than 5 mm below the level of the dorsum sellae). Good exposure of the neurovascular structures of the interpeduncular and prepontine cisterns (namely, the basilar artery) was obtained in all cases as compared with other well-established approaches to the area. All patients in our surgical series did well except that all incurred an expected third nerve palsy, caused by surgical manipulation, which resolved over the course of 2 weeks to 3 months. Although technically difficult, the transcavernous approach provides better exposure of the interpeduncular and prepontine cisterns relative to that afforded by other, more conventional approaches. The satisfactory results obtained in our preliminary series of patients greatly support the use of this approach for complex basilar tip aneurysms.