[Treatment of peripheral aneurysms of the posterior circulation]

Peripherally located aneurysms of the posterior circulation are extremely rare. The outcome of patients with peripherally located aneurysms has been poor, and the treatment of such aneurysms has been surgically challenging. We report a consecutive series of peripherally located ruptured aneurysms in the posterior circulation, and discuss in this article the optimal treatment strategy for such lesions. Clinical presentation, neuroradiological findings, treatment method, and the outcome were reviewed retrospectively. Two cases with distal posterior cerebral artery aneurysm, two with distal posterior inferior cerebellar artery aneurysm, two with anterior inferior cerebellar aneurysm, and one with superior cerebellar artery aneurysm were included in this study (mean age, 59.3 +/- 16.0, M:F = 1:6). Three patients with good neurological status on admission who underwent clipping of the aneurysmal neck via craniotomy showed a favorable outcome. In contrast, four patients with poor neurological status on admission who underwent endovascular proximal occlusion of the parent artery showed an unfavorable outcome. Although the outcome of patients who underwent endovascular surgery was poor, endovascular proximal occlusion was effective in preventing re-rupture of the aneurysms. Proximal occlusion of the parent artery has several shortcomings such as cerebral infarction, but proximal occlusion at the very distal area of the parent arteries would not be critical because of good collateral circulation. Thus, endovascular proximal occlusion may provide us another option in the treatment of peripherally located aneurysms especially in patients with poor neurological status. Further data is needed to discover the optimal treatment for patients with peripherally located cerebral aneurysms.