[Unruptured cerebral aneurysms: clinical analysis of 80 cases and its new classification].

We experienced 94 unruptured cerebral aneurysms in 80 patients in our clinic between April 1979 and March 1985, and analyzed them in the light of the symptomatological factor, diagnostical factor, significance of aneurysm itself and its treatment. Based on these clinical analysis, unruptured cerebral aneurysms were classified into the following 4 groups; Group 1: intact aneurysm in multiple aneurysms in patients with subarachnoid hemorrhage, Group 2: asymptomatic aneurysm discovered incidentally during the investigation of various diseases other than cerebral aneurysm, Group 3: symptomatic aneurysm with compression or ischemic clinical signs, or subjective symptoms due to aneurysm, Group 4: asymptomatic aneurysm screened by a noninvasive method in healthy humans, or in patients with a risk factor for cerebrovascular diseases, with diseases predisposed to aneurysm, and with minor subjective symptoms unrelated to aneurysm. Group 1 included 36 aneurysms in 31 patients, with internal carotid aneurysms being predominant; the size of 3 mm was most frequently found and those smaller than 10 mm formed in 92%. An operation for aneurysm was performed in 17 patients without operative morbidity and mortality. Among 14 unoperated patients one died of hemorrhage from an unruptured cerebral aneurysm. Indication for operation in Group 1 is determined depending on the patient's severity due to initial SAH. Group 2 was composed of 13 aneurysms in 12 patients; internal carotid aneurysm and anterior cerebral aneurysm, 5 each, being dominant. The size of 3 mm was most frequently seen and all were smaller than 7 mm. An operation was performed in 5 patients all showing a favorable course.(ABSTRACT TRUNCATED AT 250 WORDS)