PROXIMAL ANEURYSMS OF THE POSTERO-INFERIO R CEREBELLAR ARTERY - A MULTICENTER RETROSPECTIVE STUDY OF 24 CASES

Aneurysms of the postero inferior cerebellar artery (PICA) are relativ ely rare as it accounts for only 0.5 % to 3 % of all intracranial aneu rysms, even though this localization is in second place for frequency in the posterior fossa, after aneurysms of the basilar artery. Among t hem, origin from the anterior or latero-medullary segment of PICA woul d account for 80 % of cases. In this retrospective multicenter study, we report 24 cases of PICA aneurysms with their clinical and anatomic features as well as either their surgical or endovascular treatment. W e also carried out an exhaustive review of the literature in order to propose the typical clinical features of this type of lesion. Of parti cular significance : a predominance of female patients of approximatel y 50 years of age; posterior direction ; constancy of hemorrhage in th e fourth ventricle in case of ventricular involvement of subarachnoid hemorrhage. The various therapeutic possibilities are discussed and th eir results are analyzed. The prognosis for PICA aneurysms would seem to be favorable, depending, of course, on initial clinical grade.