We have experienced 53 cases with multiple aneurysms during the past 6 years and 6 months. The incidence of multiple aneurysms was 17.6% in our series. The locations with the highest probability of rupture were anterior cerebral artery (70%) and anterior communicating artery (68%). It was possible to identify which aneurysm had ruptured in 92% of the cases preoperatively. Both ruptured and non-ruptured aneurysms should be treated in a early one staged operation, except for a few cases, such as those with aneurysms, one of which was located at the posterior circulation or those with poor-risk. In our series, however, the results of early one staged operation was poor with a mortality rate of 28%. Three patients died due to the postoperative intracerebral hematoma caused by disturbance of the venous return. All 3 patients were operated by the pterional and ipsilateral interhemispheric approaches for the accompanying distal anterior cerebral artery aneurysm. Therefore, in the cases of multiple aneurysms accompanied by distal anterior cerebral aneurysm, it should be emphasized to preserve the venous circulation.
