Objective:

To compare the efficacy of responsive neurostimulation (RNS) treatment with bilateral thalamic versus corticothalamic leads.

Background:

Drug resistant epilepsy (DRE) that is not amenable to surgical resection or continues despite resection can be treated with devices, such as RNS which provides localized stimulation. There is limited data comparing RNS of bilateral thalamic nuclei (anterior nucleus (ANT), centromedian nucleus (CMT), and pulvinar) compared to corticothalamic RNS.

Design/Methods:

This is a retrospective analysis of 21 patients who underwent RNS therapy with either bilateral thalamic (17) or corticothalamic (4) leads and had >6 months of follow up. We compared if patients were responders (≥50% seizure frequency reduction) and/or if there was reported decrease in seizure severity at last follow-up.

Results:

Average age of bilateral thalamic implantation was 32 years (range 16-52) vs 41 years (range 28-56) for corticothalamic implantation. 8 patients had prior surgical resection (6 in bilateral thalamic vs 2 in corticothalamic group). All patients underwent stereo-EEG evaluation except for 2 in the bilateral thalamic cohort. Average follow-up time was 27.7 months for bilateral thalamic implantation vs 29.5 months for corticothalamic. Amongst the bilateral thalamic group, 10 had CMT implantation vs 7 had ANT implantation. Amongst the corticothalamic group, the thalamic lead was placed in ANT (2 patients), CMT (1), or pulvinar (1), and the cortical lead was placed near the seizure onset zone. 11 out of 17 (64.7%) patients with bilateral thalamic implantation (6-CMT) were responders with >50% seizure reduction, and 16 out of 17 (94.1%) patients experienced decrease in seizure severity (9-CMT). 4 out of 4 patients (100%) with corticothalamic leads were responders and reported decrease in seizure severity.

Conclusions:

This analysis shows that although bilateral thalamic RNS was recommended at our center more often, corticothalamic RNS can also be a promising treatment option to reduce seizure burden in selected patients with DRE.