The current role of microsurgery for posterior circulation aneurysms: a selective approach in the endovascular era

During the past decade, management of posterior circulation aneurysms has shifted away from microsurgery. Currently, microsurgical clipping is considered a primary, competitive alternative to endovascular coiling, or more commonly, a secondary alternative when endovascular therapy is unfavorable. We present a large, multidisciplinary team experience with posterior circulation aneurysms in an institution that continues to use microsurgery as a primary treatment modality for selected aneurysms.

During a 9-year period, 217 patients with 228 posterior circulation aneurysms were treated microsurgically; they included 106 basilar bifurcation, 27 posterior cerebral artery, 23 superior cerebellar artery, eight anteroinferior cerebellar artery, five basilar trunk, 47 posteroinferior cerebellar artery, and 12 vertebral artery aneurysms. Overall, 81% of patients presented with hemorrhage, and 33% of the aneurysms were large or giant in size.

Direct clipping was performed in 75% of cases, and the overall rate of angiographic aneurysm obliteration was 98.1%. Sixteen patients (7.4%) died after surgery, 25 patients (11.5%) experienced transient neurological deterioration, and 17 patients (7.8%) experienced permanent neurological deterioration. At late follow-up (mean duration, 13.6 mo), 144 patients had good outcomes (Glasgow Outcome Scale scores of 5 or 4, 66%), and 184 patients (85%) either improved or were unchanged relative to their preoperative baseline. Overall, mean Glasgow Outcome Scale scores improved from 3.60 to 3.97.

Despite increasing reliance on endovascular therapy with posterior circulation aneurysms, there is a role for microsurgical therapy. Microsurgery remains a competitive, primary therapy for superior cerebellar artery, P1 posterior cerebral artery, distal anteroinferior cerebellar artery, and posteroinferior cerebellar artery aneurysms. Microsurgery has become a secondary therapy for P2 posterior cerebral artery, basilar trunk, proximal anteroinferior cerebellar artery, vertebrobasilar junction, and vertebral artery aneurysms when endovascular therapy is unfavorable. The preferred therapy for basilar bifurcation aneurysms remains unclear. Collaborative, multidisciplinary teams are strengthened and results are improved by offering competitive treatment alternatives for patients to consider and select. Rather than abandoning the posterior circulation prematurely, aneurysm surgeons should maintain technical proficiency with these lesions.