gms | German Medical Science

Objective: Evaluation of the single center long-term results on efficacy and safety of deep brain stimulation (DBS) of the anterior thalamic nucleus (ANT) in patients with drug-resistant epilepsy.

Methods: In this retrospective study, clinical outcome was evaluated in all patients who had undergone ANT-DBS from November 2011 to Mai February 2018 with a minimum follow-up of 3 6 months. In all patients, DBS electrodes (Medtronic 3387) were implanted via the transventricular approach to the ANT. Last follow-was performed in August 2018.

Results: In total, 22 patients (12 male, 10 female, age 35.48±11.81 years) could werebe included. Mean follow-up was 38.8 months (range 8–84 months). The majority of patients suffered from a multifocal epilepsy syndrome (n=15), the others were diagnosed with paracentral (n=1), temporoparietal (n=1), temporo-occipital (n=1), unifrontal (n=1) or right hemispheric (n=2) seizure origin. In addition, there was one patient with a Lennox-Gastaut Syndrome. Vagal nerve stimulation (VNS) had priorly been performed in 8 patients and 5 patients had a history of microsurgical resective surgery. All but one patient (postischemic thalamic lesion) had bilateral electrode implantation. A seizure reduction of more than 50% was achieved in 15/22 (68.1%) with a reduction of more than 90% in 6/22 patients (27.2%). ANT-DBS proved to be most efficient in multifocal epilepsy syndromes of unknown or post-inflammatory etiology (7/11 (63,6%) responders, seizure reduction >90% in 5/11 (45,4%)). Side effects of stimulation (i.e. paresthesia, dizziness/vertigo, increase in seizure frequency/persistent aura symptoms, interruption of night sleep) could be reduced most effectively by increasing the amplitude slowly and in an “individualized” manner (standard stimulation-parameters: 145 Hz, 90 µs, 1 min On/5 min OFF, amplitude range 1.5–5.5V (mean 3.9 V)). Hardware-explantation was required in one responder due to chronic meningitis 21 months after implantation with ongoing seizure reduction thereafter and lesion of the nervus thoracicus longus was observed in another.

Conclusion: ANT-DBS is an effective and safe treatment option for patients with drug-resistant epilepsy who are not candidates for “respective” mircosurgery. By implementing an individualized stimulation protocol, long-term outcome was improved and stimulation-induced side-effects could be reduced in our center.