Posterior circulation aneurysms: Guideline to management

Abstract

Posterior circulation aneurysms present a difficult challenge because they are located in an exquisitely eloquent and sometimes difficult-to-reach area in the posterior cranial, fossa. Because the basilar artery and the origin of its main branches are located along the anterior aspect of the brainstem, the surgical approaches used to reach such lesions should provide enough space while avoiding undue restriction of the brainstem and cerebellum. A thorough knowledge of the microsurgical anatomy of the posterior fossa and posterior circulation is mandatory for a successful operation. We use the pretemporal approach to deal with small and apparently simple basilar bifurcation aneurysms, as well as for most superior cerebellar artery aneurysms. The transcavernous-transellar approach is performed for large, complex, or low-lying basilar bifurcation aneurysms. A lateral skull base approach is usually performed to operate on aneurysms located on the mid-third of the basilar artery and at the vertebrobasilar junction. We usually perform the presigmoid supra- and infratentorial approach for mid-third basilar aneurysms. Vertebrobasilar junction aneurysms may also be approached through a suboccipital-transcondylar approach. PICA aneurysms are approached through either a retrosigmoid or a far-lateral approach, depending on their exact location in the posterior fossa. The surgical approach and procedure should be tailored to each specific aneurysm, taking into account the aneurysm's size, location, and relationships with surrounding neurovascular structures, as well as the regional blood flow dynamics.