Results of Direct Intracranial Surgery and Classification for 135 Anterior Communicating Artery Aneurysms

ABSTRACT

During the 10-year period up to December 1984, 176 patients with anterior communicating aneurysn(ACOMA) among total 467 patients of intracranial aneurysms were admitted to this Catholic Medical Center. Of these, 135 cases of ACOMA were operated by direct intracranial procedures. To analyse the factors influencing the mortality involving in surgery of 135 patients with ACOMA, a classification of ACOMA was attempted. The origins and projections of aneurysms, anatomical variations were analysed with the aid of angiography, intraoperative findings and intraoperative photographs which permitted the establishment of a classification of ACOMA with their direction. Our classification of operated 135 cases of ACOMA are seven types : 32 anterior(23.7%), 30 anterior-rostral(22.2%), 42 antefior-caudal(31.1%), 3 posterior(2.2%), 18 posterior-rostral(13.4%), 4 posteriorcaudal(3.0%), caudal 6(4.4%), respectively. Most of ACOMA projecting anteriorly, anterio-rostrally were situated above or between the optic nerve, and the less frequent posterior-caudal and inferior aneurysms were in close proximity to hypothalamic branches of the anterior communicating artery and A2 segment. There was on overall operative mortality of 6%. The surgical morbidity and mortality were significantly higher in the posteriorly projecting group, garticulary in the posterior-caudal direction. In direct surgery of ACOMA, subpial resection of the gyrus rectus was effective for not only anteriorly, but also posteriorly directing aneurysms.