The authors reviewed surgical results of 618 surgically treated patients with intracranial aneurysms. Multiple aneurysms were observed in 106 (20%) patients. In cases of multiple aneurysms, their policy has been to treat all aneurysms, ruptured and unruptured, in a one-stage operation whenever possible. All aneurysms of 92 patients were treated in one-stage operations. Eighty three (90%) patients improved or remained stationary, 6 (7%) deteriorated, 3 (3%) died postoperatively. The cause of deterioration or death were due to cerebral vasospasm, primary brain damage or surgical procedure for ruptured aneurysms. No significant difference was found in comparing the rupture site of the aneurysm or the timing of the operation in each preoperative clinical grade. Furthermore, all patients were classified into three groups according to the location of the aneurysms. Sixty-two patients had unilateral aneurysms including aneurysms in the midline, i.e. anterior communicating artery aneurysms, distal basilar artery aneurysms and/or bilateral pericallosal artery aneurysms (unilateral group), and 30 patients had bilateral aneurysms (bilateral group). Morbidity and mortality in unilateral group was 6% and 3%, while in bilateral group, 7%, 3% respectively. No significant difference was observed in the bilateral group compared with the unilateral group, and surgical results of each group appeared to be satisfactory. Neither death nor deterioration was found attributable to operative procedure when unruptured aneurysms were added to the surgery for ruptured aneurysms in a one-stage operation. These surgical results for 92 cases were similar to the results in the rest of the 526 cases. Based on these results, the one-stage operation is recommended, whenever possible, for patients with multiple aneurysms, even if bilateral craniotomy is needed.
