Gamma knife surgery for refractory insular cortex epilepsy.

Background: Resection of the epileptogenic insular cortex is surgically challenging. We sought to evaluate the potential of Gamma Knife surgery (GKS) for the treatment of pharmacoresistant insular cortex epilepsy (ICE) in patients who underwent GKS between 2005 and 2010. Adverse events and effects on seizure frequency were assessed.

Methods: Three cases of refractory ICE were treated by GKS between 2005 and 2010.

Results: Case 1 had refractory nonlesional ICE, proven by depth electrodes only partially helped by a left posterior insulectomy. Case 2 had refractory ICE due to a left insular cavernoma. Case 3 had refractory ICE, confirmed by an invasive study but complicated by transient dysphasia from contusion of Wernicke's area. The marginal and maximum radiation doses delivered were 20 and 40 Gy, respectively. Treatment volume ranged from 1.2 to 3.2 cm3. Two out of 3 patients experienced significant seizure reduction and the third had a worthwhile improvement (follow-up 30-76 months). Complete antiepileptic drug withdrawal was un-fortunately not possible. Complications included transient lightheadedness and new-onset seizures responsive to medical treatment, both in the same patient.

Conclusion: GKS is a promising technique for selected drug-resistant ICE patients. Additional observations are necessary.