Post-responsive Neurostimulation Surgeries – Experience Across Two Level 4 Epilepsy Centers
Abstract number :
2.406
Submission category :
18. Case Studies (case reports and small series less than 5 subjects will not be accepted)
Year :
2022
Submission ID :
2204868
Source :
www.aesnet.org
Presentation date :
12/4/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:26 AM
Authors :
Andrew Lin, MD – University of Texas Southwestern Medical Center; Irina Podkorytova, MD – University of Texas Southwestern Medical Center; Mark Agostini, MD – University of Texas Southwestern Medical Center; Sasha Alick Lindstrom, MD – University of Texas Southwestern Medical Center; Kan Ding, MD – University of Texas Southwestern Medical Center; Jay Harvey, DO – University of Texas Southwestern Medical Center; Ryan Hays, MD – University of Texas Southwestern Medical Center; Bradley Lega, MD – University of Texas Southwestern Medical Center; Ghazala Perven, MD – University of Texas Southwestern Medical Center
Rationale: The NeuroPace Responsive Neurostimulation (RNS) System is a safe and effective treatment to reduce seizure frequency in patients with drug-resistant focal epilepsy (DRE) when resective or ablative surgery is not feasible. This system also offers the opportunity for ambulatory electrocorticography (ECoG) monitoring, which has been investigated as an additional resource or complement in the evaluation of epilepsy. We aim to review and characterize surgical interventions and their clinical outcomes in patients who have undergone treatment with RNS and to evaluate how chronic ambulatory ECoG data inform these decisions.
Methods: The study included patients who received RNS treatment and subsequently underwent surgical intervention for DRE at two Level 4 epilepsy centers from 2014 to 2022. We retrospectively analyzed response to RNS treatment and post-RNS surgery in this patient cohort.
Results: Ten out of 90 patients treated with the RNS system at our centers met inclusion criteria. The etiologies of epilepsy were unknown in five patients, structural in four patients, and autoimmune in one patient. The rationales for treatment with RNS included two or more seizure foci, concerns for eloquent cortex, and poorly localized seizure onset. One patient had remote history of temporal lobectomy, and two patients had destructive intervention before RNS placement as part of their treatment plans. After treatment with RNS, half of the patients achieved a worthwhile seizure reduction (Engel classification III or better) and half of the patients did not (Engel classification IV). For their post-RNS surgical interventions, nine out of ten patients received some form of destructive treatment. Chronic ECoG data guided surgical intervention in six of these patients. In three, the ECoG data helped to determine the predominant seizure focus in “real world” settings, and in the other three it confirmed continued epileptogenicity leading to intervention. The three remaining patients who received destructive treatment required repeat intracranial evaluation prior to surgery due to ambiguity of seizure onset. One patient was transitioned from RNS to deep brain stimulation of the bilateral anterior thalamic nuclei. Following post-RNS surgical intervention, five patients achieved improvement in their seizure control, including two who became seizure-free, while four patients did not (one patient with autoimmune epilepsy, one patient with bilateral lesions, and two patients with non-lesional MRI: one with bilateral seizures and one with regional seizure onset). One patient was lost to follow-up.
Conclusions: Our study demonstrates how the RNS system and ambulatory ECoG monitoring can be used to inform subsequent treatment strategies for patients with drug-resistant focal epilepsy. Post-RNS surgery helped improve seizure burden in five out of ten patients in this cohort, including two patients who became seizure-free. Additional studies are needed to determine how best to utilize information from ambulatory RNS ECoG recordings to guide epilepsy treatment.
Funding: None
Case Studies (case reports and small series less than 5 subjects will not be accepted)