Pretemporal Transcavernous Approach for Microsurgical Clipping of Giant, Embolized, and Lower Basilar Tip Aneurysms

Objective: To demonstrate in a stepwise fashion the microsurgical anatomy of the pretemporal transcavernous approach to the interpeduncular region to face giant embolized and low basilar tip aneurysms.

Design: We used the pretemporal transcavernous approach for reaching interpeduncular region in patients with low basilar tip aneurysms.

Patients: Fifteen patients presented with basilar tip aneurysms located lower than or at the level of posterior clinoid process; of these, five embolized basilar tip aneurysms and three giant basilar tip aneurysms were submitted to the pretemporal transcavernous approach instead of the pterional approach for reaching interpeduncular and prepontine cisterns.

The patients were operated on at Hospital Beneficência Portuguesa de São Paulo between January 2006 and December 2011. All patients were preoperatively studied using angiographic CT scan and digital angiography. Ruptured and unruptured aneurysms were included.

Results: A better exposure of all neurovascular structures was obtained by the pretemporal transcavernous approach instead of the pterional custom approach.

Conclusion: Classical pterional craniotomy offers the surgeon the transsylvian and subfrontal approaches. Pretemporal transcavernous craniotomy not only offers these approaches, but also adds temporopolar and subtemporal approaches. The temporopolar approach, which is performed by microdissection of the oculomotor nerve and the temporal lobe posteriorly, widely exposes the interpeduncular cistern, both posterior cerebral arteries, both superior cerebellar arteries, the basilar artery bifurcation, aneurysm neck, and posterior thalamoperforate arteries. It also eases access to the proximal aneurysm control.

The transcavernous approach provides better exposure for complex basilar tip aneurysms.