[Symptomatic aneurysms of the postero-inferior cerebellar artery. A multicenter retrospective study of 29 cases].

A multicenter retrospective study of 29 cases of posterior inferior cerebellar artery is reported. Over a period of 21 years, the frequency of posterior inferior cerebellar artery aneurysm among all intracranial aneurysm was estimated to 1.38 p. 100 of cases of aneurysms followed by 3 University Hospitals. Frequency of rupture appeared to be very high (93 p. 100) in this series probably because of the type of selection. Average grade of presentation according to Hunt and Hess classification being < III in 3 fourth of the cases. Neither clinical presentation nor suspicious etiological factors were specific of this localization. Only two cases were of pseudotumoral appearance. Positive diagnosis of subarachnoid hemorrhage was made by CT scan. Angiograms gave diagnosis of localization of the malformation and its type. Intraventricular hemorrhage was found in 62 p. 100 of our cases: all had hemorrhage of the fourth ventricle. Hydrocephaly was more frequent as compared to supratentorial localizations, Vasospasm was less frequent as in supratentorial localizations. Nimodipin seems to be efficient. Therapeutic possibilities are primary dominated by surgery with good results when it is possible. Endovascular treatment is under evaluation.