Long-term outcome of anterior thalamic nucleus stimulation for intractable epilepsy.

Background: Many patients with epilepsy have persistent seizures despite treatment with maximal antiepileptic drug therapy and are not candidates for resective brain surgery.

Objectives: We investigated the effectiveness of seizure reduction after anterior thalamic nucleus (ATN) stimulation in patients with intractable epilepsy undergoing deep brain stimulation (DBS) of the thalamus.

Methods: Patients included in this study had poorly controlled seizures, despite anticonvulsant medication, and were not candidates for surgical resection of an identifiable seizure focus. Fifteen patients with medically refractory epilepsy underwent the placement of bilateral DBS electrodes in the anterior thalamus. The seizure frequency was monitored and compared with the preimplantation baseline.

Results: The treatment demonstrated a statistically significant decrease in the seizure frequency, with a mean reduction of 70.4% (mean follow-up, 27 months). Two of the patients had a remarkable reduction of seizure frequency.

Conclusion: It seems to be important that the short-term outcome of ATN DBS reflects the long-term outcome directly. The correlation between the seizure type, characteristics and anticonvulsant effects of ATN DBS did not exhibit significance because of the small number of cases. Therefore, a longer-term follow-up with a larger group of patients is required to fully evaluate the safety and effectiveness of this treatment modality.