[Epilepsy after operation for ruptured intracranial aneurysm].

Fifty-five patients who underwent surgery for ruptured aneurysm of the anterior circulation were evaluated with respect to postoperative epilepsy. Prophylactic treatment with anticonvulsants had been carried out in all patients. The overall incidence of the postoperative epilepsy was 23.6% (13/55). The mean latency between the operation and the first seizure was 11 months (range, 8 days to 5 years). The most important risk factors by statistical analyses were multiple aneurysms, preoperative severity, severe subarachnoid hemorrhage, intracerebral hematoma, normal pressure hydrocephalus, EEG abnormalities in the chronic stage, intracerebral low density area on CT-films and neurological deficit. Other risk factors were aneurysm of MCA and early operation for aneurysm. Our opinions concerning postoperative anticonvulsant therapy for aneurysmal patients are as follows. 1) Prophylactic treatment with anticonvulsant should be administered to all patients who have undergone aneurysm surgery. 2) The risk factors should be considered in determining the duration of medication with the anticonvulsant. 3) The treatment with the anticonvulsant should be performed while monitoring the clinical course, EEG findings, plasma concentration level of the anticonvulsant and side effects of the drugs.