Failure of Combined Treatment for the Thrombosed Posterior Cerebral Artery Aneurysm

It is sometimes difficult to preserve the proximal patent arteries when surgically treating a complex aneurysm located at the P2P3 segment of the PCA. In such cases, revascularization of the distal posterior cerebral artery (PCA) may prevent the development of postoperative ischemic complications with visual field defects. We report the revascularization of the distal PCA territories of a patient with a partially thrombosed aneurysm located at the P2P3 segment of the PCA, and the postoperative course. A 42-year-old man with a large partially thrombosed aneurysm located at the P2P3 segment of the right PCA presented with left hemiparesis. Due to the aneurysm is localization in the cerebral peduncle, primary clipping or endovascular occlusion was considered to be too hazardous. After the occipital artery (OA) to the PCA were anastomosed with a lateral semiprone position, postoperative cerebral angiography demonstrated perfusion of the right PCA from the right OA via the anastomosis, and the aneurysm was successfully treated with simultaneous occlusion of the aneurysm and parent PCA with coils in one anesthesia. The patient had an uneventful postoperative course through day 4, but on day 5, severe cerebral infarction was revealed on the right occipital lobe. OA-PCA anastomosis is a useful method of treatment choice of complex PCA aneurysm, but perioperative antiplatelet therapy is also important to improve the outcome.