[A case report of a distal posterior cerebral artery (P3) aneurysm, not accessible through a subtemporal approach].

A case of a ruptured aneurysm located in the P3 portion of the posterior cerebral artery (PCA), which was not accessible through a subtemporal approach, was reported. In addition to the case presented here, alternative operative approaches to the distal P3 portion or higher ambient cistern were reviewed and discussed. A 64-year-old man was admitted because of sudden onset of headache. CT scan disclosed SAH which was recognized mainly in the left ambient cistern with intraventricular bleeding (Fisher Group 4, Hunt and Kosnik Grade 2). A left vertebral angiogram disclosed a small saccular aneurysm in the distal P3 portion of the left PCA, which was located as highly as the plexal point of the anterior choroidal artery. On day 4, neck clipping was tried via the left subtemporal approach. The distal P3 aneurysm, however, could not be reached by this approach, in spite of aspiration of the parahypocampal gyrus. On day 7, the patient died of massive bleeding from a Cushing ulcer. It was considered that an occipital interhemispheric approach might have been more suitable in the present case.