A multicenter retrospective study of patients treated in the thalamus with responsive neurostimulation

• Authors: Madeline C. Fields, Icahn School of Medicine; Onome Eka, Icahn School of Medicine; Cristina Schreckinger, St. Mary's Health Care System; Patricia Dugan, New York University; Wael F. Asaad, Brown University; Andrew S. Blum, Brown University; Katie Bullinger, Emory University; Jon T. Willie, Washington University in St. Louis; David E. Burdette, Corewell Health; Christopher Anderson, Medical College of Wisconsin; Imran H. Quraishi, Yale University; Jason Gerrard, Yale University; Anuradha Singh, Icahn School of Medicine; Kyusang Lee, Icahn School of Medicine; Ji Yeoun Yoo, Icahn School of Medicine; Saadi Ghatan, Icahn School of Medicine; Fedor Panov, Icahn School of Medicine; Lara V. Marcuse, Icahn School of Medicine
• Journal Title: Frontiers in Neurology
• Volume: Volume 14
• Publisher: Frontiers | 2023-09-08, Pages 1202631-None
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.3389/fneur.2023.1202631
• Subjects: Biology, Neuroscience
• Keywords: centromedian nucleus of thalamus; anterior thalamic nucleus; neuromodulation; responsive neurostimulation (RNS); drug-resistant epilepsy (DRE); epilepsy surgery

Abstract

Introduction For drug resistant epilepsy patients who are either not candidates for resective surgery or have already failed resective surgery, neuromodulation is a promising option. Neuromodulatory approaches include responsive neurostimulation (RNS), deep brain stimulation (DBS), and vagal nerve stimulation (VNS). Thalamocortical circuits are involved in both generalized and focal onset seizures. This paper explores the use of RNS in the centromedian nucleus of the thalamus (CMN) and in the anterior thalamic nucleus (ANT) of patients with drug resistant epilepsy. Methods This is a retrospective multicenter study from seven different epilepsy centers in the United States. Patients that had unilateral or bilateral thalamic RNS leads implanted in the CMN or ANT for at least 6 months were included. Primary objectives were to describe the implant location and determine changes in the frequency of disabling seizures at 6 months, 1 year, 2 years, and > 2 years. Secondary objectives included documenting seizure free periods, anti-seizure medication regimen changes, stimulation side effects, and serious adverse events. In addition, the global clinical impression scale was completed. Results Twelve patients had at least one lead placed in the CMN, and 13 had at least one lead placed in the ANT. The median baseline seizure frequency was 15 per month. Overall, the median seizure reduction was 33% at 6 months, 55% at 1 year, 65% at 2 years, and 74% at >2 years. Seizure free intervals of at least 3 months occurred in nine patients. Most patients (60%, 15/25) did not have a change in anti-seizure medications post RNS placement. Two serious adverse events were recorded, one related to RNS implantation. Lastly, overall functioning seemed to improve with 88% showing improvement on the global clinical impression scale. Discussion Meaningful seizure reduction was observed in patients who suffer from drug resistant epilepsy with unilateral or bilateral RNS in either the ANT or CMN of the thalamus. Most patients remained on their pre-operative anti-seizure medication regimen. The device was well tolerated with few side effects. There were rare serious adverse events. Most patients showed an improvement in global clinical impression scores.