We review 16 cases of distal posterior inferior cerebellar artery (PICA) aneurysm. Of 2691 ruptured aneurysms in the Nagasaki Subarachnoid Hemorrhage Studying Group Data Bank from January 1989 to December 1998, 15 distal PICA aneurysms (0.6%) were reported. We encountered a case of extracranial distal PICA aneurysm in 1999. Including this case, 16 distal PICA aneurysms were reviewed in this study. Eight patients underwent neck clipping of aneurysm, and GDC embolization was done in 1. Rebleeding after admission appeared in 6 patients (40%): 3 patients of Grade III, 2 of Grade IV, and one of Grade V on admission. The outcome was poor in these 6 patients. All 4 patients of good grade (H & K Grade I and II) and 2 of 5 patients of Grade III underwent neck clipping without rebleeding. Excellent outcomes were obtained in these 6 patients. Furthermore, of 5 patients with Grade V, 2 patients had a favorable outcome. These results suggest that careful management to prevent rebleeding might yield a good outcome even in poor grade patients.
