[Ruptured Aneurysms on the Cortical Segment of the Distal Posterior Inferior Cerebellar Artery:A Report of Two Cases and a Literature Review].

: Two unusual cases of ruptured distal posterior inferior cerebellar artery(PICA)aneurysm on the cortical segment were successfully treated with open surgery. A 76-year-old woman presented with a Hunt and Kosnik(H&K)grade II Subarachnoid hemorrhage(SAH). CT showed a slight SAH in the cisterna magna and around the vermis, and fourth intraventricular hematoma. Cerebral angiography revealed an aneurysm on the cortical segment of the distal PICA. Intraoperative findings identified the aneurysm as fusiform. Trapping of the aneurysm was performed, and the indocyanine green angiography fiuding confirmed aneurysmal flow disappearance and good circulation in the cerebellar cortex. An 89-year-old woman presented with H&K grade II SAH. CT revealed a thick SAH in the posterior cranial fossa, and third to fourth intraventricular hematoma with hydrocephalus. Cerebral angiography revealed an aneurysm on the cortical segment of the distal PICA. Intraoperative findings showed that the aneurysm was fusiform. Trapping and resection of the aneurysm were performed. Thirteen previous cases of aneurysms on the cortical segment of the distal PICA have been reported. Distal PICA aneurysms apparently show rebleeding more frequently than do aneurysms at other locations, so immediate direct surgery is necessary to avoid rebleeding. After proximal ligation or trapping of the aneurysm, indocyanine green angiography is useful to determine the need for revascularization.