Long-term Anterior Thalamus Stimulation for Intractable Epilepsy

Background: Deep brain stimulation (DBS) has re-emerged as an alternative therapy forintractable epilepsy. In this study, we investigated the feasibility, efficacy andsafety of long-term anterior thalamic nucleus (ATN) stimulation forintractable epilepsy.Methods: In this open-label pilot study of electrical stimulation of the ATN, we investigatedfour cases of intractable epilepsy (one man with generalized seizure,and three woman with partial seizure and secondary generalization; agerange, 18-45 years), with a follow up of 2 years. Under the indication ofbilateral or nonlocalized epileptic foci, each patient underwent stereotacticimplantation of a quadripolar stimulating electrode in the bilateral ATN,guided by single-unit microelectrode recording. The stimulator was turnedon after a sham period of 2-4 weeks. Seizure frequency was monitored andcompared with the pre-implantation baseline. Twenty-one similar casesreported in the literature during the past 20 years were reviewed.Results: Insertion into and stimulation through electrodes implanted in the ATNdecreased seizure frequency, with a mean reduction rate of 49.6% in the currentseries. Two patients had seizure reductions of ≥ 60%, with completeremission achieved in one patient. These findings were consistent with thosein four other investigations of intractable epilepsy, which showed an overallrate of 45-55% in seizure reduction. One of our patients suffered a smallfrontal hemorrhage, and a second patient had extension erosion over thescalp; however, no resultant major or permanent neurological deficits wereobserved.Conclusions: Based on our study results and literature review, it appears reasonable to concludethat long-term ATN stimulation is a safe and effective treatment forseizure reduction in patients with intractable epilepsy.