Abstracts

Would Selective Unilateral ANT-DBS Be an Alternative to Bilateral ANT-DBS That Offers Comparable Efficacy in Seizure Control in Drug-resistant Temporal Lobe Epilepsy?

Abstract number : 1.54
Submission category : 9. Surgery / 9A. Adult
Year : 2024
Submission ID : 1421
Source : www.aesnet.org
Presentation date : 12/7/2024 12:00:00 AM
Published date :

Authors :
Presenting Author: Junhyung Kim, MD – Asan Medical Center

Seok Ho Hong, MD, PhD – Asan Medical Center

Rationale: Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) is a recognized treatment for drug-resistant epilepsy, particularly in cases involving temporal lobe seizures. However, the optimal approach regarding unilateral versus bilateral stimulation remains debated. Frontotemporal epilepsy has been associated with better outcomes, likely due to the involvement of specific functional circuits within the ANT. Recent reports have shown that unilateral ANT ablation can result in acceptable seizure reduction, prompting questions about the necessity of bilateral stimulation for effective neuromodulation of the thalamo-cortical and amygdalohippocampal networks. While bilateral stimulation has been extensively studied, the efficacy of unilateral stimulation has been less thoroughly explored.

Methods:

This study aims to evaluate the clinical outcomes of ANT-DBS, focusing on the volume of tissue activated during unilateral or bilateral stimulation. We reviewed clinical and neuroimaging data from a series of patients with drug-resistant temporal lobe epilepsy who underwent ANT-DBS surgery at a single institution between 2005 and 2023. The volume of tissue activated and seizure reduction was assessed separately during various DBS programming phases.



Results: Anatomical mapping identified 13 patients with valid seizure records who received ANT stimulation either unilaterally or bilaterally over a median period of 28.0 (IQR, 21.4–62.0) months. Patients achieved a median seizure reduction of 75.1% (IQR, 65.6–86.1) during bilateral ANT stimulation, with 10 patients (76.9%) classified as DBS responders, achieving more than a 50% reduction in seizure frequency. Five patients maintained unilateral ANT stimulation on the dominant (left) side for a median duration of 12.0 months (IQR, 9.6–12.2), in addition to periods of bilateral stimulation. These patients experienced a median seizure reduction of 55.6% (IQR, 15.3 – 74.2), representing a mean difference of -20.1% (IQR, -58.9 to -15.3) compared to corresponding periods of bilateral stimulation. Despite this difference, three of these patients remain classified as DBS responders. Diffusion tensor imaging with seeding from the volume of tissue activated indicated that unilateral ANT stimulation could functionally involve both hemispheres. This finding suggests that this strategy could be considered in highly selected cases where irritative zones are within those cortical areas activated, as inferred by the anatomical mapping through the volume of tissue activated.

Conclusions: ANT-DBS is a viable treatment option for focal epilepsy that requires tailored strategies in DBS targeting and programming. While careful patient selection is important, unilateral or staged ANT stimulation could be considered as a targeted neuromodulation approach for suitable candidates with temporal lobe epilepsy.

Funding: None

Surgery