Targeted multinodal thalamic deep brain stimulation for epilepsy: A retrospective case series

Emerging literature suggests that multi-lead thalamic DBS may be safe and therapeutically beneficial to patients with diffuse or poorly defined epileptic networks; however, more studies are needed to support such off-label methods. Here, in a single-center retrospective, non-controlled observational pilot study, we investigated the off-label use of a multinodal thalamic DBS system in patients with medically refractory and poorly localized epilepsies.

Utilizing either a robotic or frame-based technique, we implanted four DBS leads (Boston Scientific, Marlborough, MA) into either bilateral (1) ANT and CM (n = 6 patients) or (2) ANT and PLV (n = 4 patients). In five patients, only bilateral ANT (n = 2) or CM (n = 3) stimulations were applied while in five other patients, bilateral ANT was supplemented with bilateral CM (n = 1) or PLV (n = 4) DBS. The thalamic targets were personalized in each patient based on available clinical or intracranial multi-site thalamic stereoencephalography or scalp EEG evidence. Primary outcomes were intraoperative and postoperative complications as well as changes in seizure frequency.

DBS implantation was well tolerated with no intraoperative complications. Only one patient had a post-operative wound-related complication. Average follow-up was 12.4 months (range 3-21 months). Most patients (nine out of 10 patients) experienced a clinically noticeable reduction in seizure frequency, including a subset (two out of 10 patients) who were seizure free. Efficacy was similar in the two-lead and four-lead stimulation groups.

This cohort provides early and preliminary data documenting the feasibility and safety (and clinical utility) of targeted multinodal thalamic DBS for medically refractory, poorly localized epilepsy. As this was not a controlled outcomes study, the clinical efficacy data must be interpreted cautiously. Our findings may motivate larger controlled studies to rigorously evaluate the clinical efficacy of personalized optimization of multinodal configuration in patients with diffuse or poorly defined epileptic networks.