Epilepsy following neurosurgical intervention.

The incidence of post-surgical epilepsy has been reported to be very high, and related to the pathological condition, to the surgery itself, and, particularly in the case of aneurysms, to the site of the lesion. Prophylactic anti-convulsant medication has been widely recommended on the basis of the perceived high risk of epilepsy. A prospective analysis of one hundred consecutive survivors of aneurysm surgery treated in a consistent microsurgical manner was performed to assess the incidence and causation of post-operative seizures. Three patients had a single early post-operative seizure. All three had predisposing features; a previous epileptic history in two, and neurological deficit in the other. Only one patient developed repeated seizures (epilepsy); he had major parenchymal damage. Seizures did not occur during a two to six year follow up in survivors of aneurysm surgery who did not have a previous epileptic history or a persistent post-operative neurological deficit. The site of aneurysm did not influence the development of epilepsy, and middle cerebral aneurysms were not associated with an increased risk. The low risk of epilepsy does not justify routine anti-convulsant prophylaxis.