Results of early operations on cerebral aneurysms.

In 625 cases of cerebral aneurysms operated upon from 1971, those in which operation was performed within the first week after subarachnoid hemorrhage had the highest mortality. However, a closer analysis of these cases revealed that the results of surgical treatment were significantly different with each day. The mortality rates resulting from operation on the first and second days were low in comparison with the remaining days of the week. To evaluate the differences, the cases are presented and the best timing of surgery is discussed.