The timing of surgery and vasospasm.

The relationship of time of surgery and vasospasm is influenced by three factors: (1) the time course of vasospasm, (2) the effectiveness of clot removal at surgery, and (3) the choice of medical management to prevent rebleeding and to treat vasospasm. Data to date demonstrate that angiographic vasospasm and vasospasm-related deficits occur in the period from 4 to 14 days after subarachnoid hemorrhage. Surgical intervention in the period of risk for vasospasm is associated with higher morbidity and mortality rates. Morbidity and mortality rates are lowest following surgery in patients who have delayed surgery; however, morbidity and mortality rates for overall management are equivalent for patients with early surgery because of vasospasm and rebleeding in patients waiting for delayed surgery. The surgical removal of the clot may be accomplished in only a limited number of patients, and most series do not reflect a large change in vasospasm occurrence following early surgery. Changes to more aggressive medical therapy in terms of prevention or reversal of ischemia from vasospasm rendered after the aneurysm is clipped and rebleeding is prevented have been initiated during the past decade. The effectiveness and safety of these treatments may play an important future role in the choice of time of surgery and the relationship of time of surgery to vasospasm-related deficits.