The International Cooperative Study on Timing of Aneurysm Surgery--an update.

The timing of aneurysm surgery is one of the major controversies in the management of subarachnoid hemorrhage. The Cooperative Aneurysm Study is conducting an international epidemiological study to determine mortality and morbidity related to timing of surgery. From January, 1981 to July, 1983 over 3,500 patients have been registered from 68 centers. This preliminary report updates the progress of the study, describes the patient population, and presents overall outcome results.