Distal posterior cerebral artery aneurysms--three case reports.

One case of an aneurysm in the P3 segment and two cases of aneurysms in the P4 segment of the posterior cerebral artery are described. The P3 aneurysm in a 60-year-old female and a P4 aneurysm in a 63-year-old male were clipped or coated via the occipital interhemispheric approach. The other P4 aneurysm in a 73-year-old female was clipped via a hematoma cavity. The occipital interhemispheric approach should be selected for small or large P3 aneurysms and for P4 aneurysms associated with slack brain, as brain retraction is minimal and the approach to the aneurysm is straightforward.