Current status of epilepsy surgery.

In the United States, there are approximately 75,000 patients with medically intractable epilepsy of focal origin who are candidates for ablative surgery. Currently, about 1500 epilepsy operations are performed per year in the United States. Candidates for ablative surgery (i.e., removal of epileptogenic tissue) are those with a reasonable chance of reduction in seizure frequency and improvement of overall lifestyle. The epileptogenic tissue must be localized preoperatively by either non-invasive or invasive recordings, or by imaging studies (e.g., MRI). Nearly 60% of all patients who undergo resection of a temporal or extra-temporal seizure focus become seizure free, and about 70% have no seizures or only rare ones. The most commonly performed operation is anterior temporal lobectomy. This update article will also review the results of other epilepsy operations which are currently performed--hemispherectomy, corpus callosotomy, and multiple subpial transection.