Gamma knife radiosurgery for refractory medial temporal lobe epilepsy

Thirty percent of localization-related, focal epilepsy remains intractable to medical treatment, even with the wide selection of antiepileptic medications now available, and is considered for surgical resection of the region identified to generate seizures. The most refractory epilepsy syndrome, and therefore the most studied, understood, and often operated, is medial temporal lobe epilepsy with the accompanying substrate of mesial temporal sclerosis. These patients fail optimal medical treatment more than 50% of the time, while resection of anteromedial temporal lobe cures seizures in about 70%; most remain seizure-free long term, usually without medications, and almost always without neurologic compromise.^1,2 Still, there are some failures (30–40%), some relapses (15–25%), and certain exclusions (when verbal memory is well preserved, resection carries the risk of significant verbal memory decline).^1–4

The first gamma knife treatment for temporal lobe epilepsy occurred in 1993 in Marseilles, following the observation that gamma knife therapy for arteriovenous malformations and some tumors also improved seizures.⁵ The first patient had immediate cessation of seizures without adverse effects, which led to subsequent application …