Abstracts

Rationale: Neuromodulation is now a common treatment pathway for focal epilepsies not readily amenable to surgical resection of the seizure focus. Bilateral anterior nucleus of the thalamus (ANT) deep brain stimulation (DBS) was approved by the FDA in 2018 for the treatment of medically refractory focal epilepsy. However, there are no devices yet approved for the treatment of genetic generalized epilepsy (GGE). Similarly, for Lennox-Gastaut syndrome (LGS) it is not clear which is the best site for neuromodulation. The ESTEL study published in 2022 provided evidence for the efficacy of centromedian nucleus of the thalamus (CMT) stimulation in LGS. CMT neuromodulation is also actively being investigated for GGE (NAUTILUS Trial). The efficacy of bilateral ANT DBS for GGE or LGS is not well-established.

Methods: This is a single institution retrospective review of all bilateral ANT DBS performed for medically refractory genetic generalized epilepsies or Lennox-Gastaut Syndrome. Cases at our institution are serially tracked, and when sufficient follow up is available, seizure frequency outcomes are reported here. Seizure frequencies were obtained from chart review comparing reported seizure frequencies at last clinic visit preceding surgery and those reported at last follow up.

Results: We identified eight patients with GGE and six with LGS who received bilateral ANT DBS between 12/2018 and 11/2023. Specific epilepsy syndromes (when specified in the chart) and seizure frequency outcomes are presented in table 1. One patient died within two months of surgery and another moved out of state immediately following surgery. Of the remaining six patients with GGE, three were responders ( >50% seizure reduction), and one patient with GGE was free of seizures at last follow up. Of the six patients with LGS, four were responders. Of the nonresponders, one had their DBS turned off due to behavioral side effects, and one with LGS secondary to Angelman’s syndrome received subsequent bilateral CMT RNS with good response.

Conclusions: Although the zeitgeist in the epilepsy community is towards CMT neuromodulation for both GGE and LGS, our limited experience with ANT DBS suggests this may also be a viable target in certain patients. Further studies are required to identify specific patient features that may direct the ideal thalamic targets (e.g. scalp EEG features) or if thalamic stereoEEG can assist in this decision.

Funding: None