Clinical Features of Ruptured Proximal Anterior Cerebral Artery Aneurysms

Choi, Seung Jin; Kye, Dae Kon; Park, Choon Keun; Lee, Sang Won; Yoo, Do Sung; Kim, Dal Soo; Park, Hae Kwan; Kang, Joon Ki

Abstract

Aneurysms arising from the proximal segment(A1) of anterior cerebral artery are rare and not classified as a separate entity. This study reviewed clinical features of A1 aneurysms in four patients the authors experienced with analysis of neurological status, radiological findings, surgical management and outcome. The incidence of A1 aneurysms among 648 aneurysmal patients operated between January. 1995. and January 1998 was 0.6%. The cases were divided into two groups according to the location of aneurysm in the course of A1 segment: distal aneurysm of A1 segment arising near the anterior communicating artery(3 cases) and proximal aneurysm of A1 segment arising near the bifurcation of internal carotid artery(1 case). All three patients of distal aneurysm showed Hunt & Hess grade III-IV on admission and intraventricular hemorrhages in CT scan, on the other hand, one patient of proximal aneurysm showed Hunt & Hess grade II and no other hemorrhage except subarachnoid hemorrhage. In microsurgical fields, the domes of aneurysm of A1 segment directed superiorly in all cases, and in 2 cases of distal aneurysm, the domes were embedded within adjacent parenchyma of gyrus rectus. Distal fenestration of A1 segment which could not be detected in preoperative angiogram was found in 2 cases of distal aneurysm. The authors propose that aneurysms of A1 portion may tend to arise mainly at the distal portion of A1 segment and tend to be accompanied with distal fenestration, and also consider that, when outbreak of aneurysmal rupture, it may give rise to intraventricular hemorrhage through the frontal horn of lateral ventricle due to superior direction of aneurysm and tendency of embedding within brain parenchyma of gyrus rectus, and then it makes the patient worse than aneurysmal rupture of other common sites.