Impact of Time to VNS Implantation on Seizure Reduction in Patients with Refractory Epilepsy
Abstract number :
2.433
Submission category :
9. Surgery / 9A. Adult
Year :
2024
Submission ID :
86
Source :
www.aesnet.org
Presentation date :
12/8/2024 12:00:00 AM
Published date :
Authors :
Presenting Author: Emma Dunn, BS – University of South Florida
Adam Alayli, BS – University of South Florida
Deborah Liaw, MD – University of South Florida Morsani College of Medicine
Zeegan George, MD – University of South Florida
Keaton Piper, MD – University of South Florida
Elliot Neal, MD – University of South Florida
Ushtar Amin, MD – University of South Florida Morsani College of Medicine
Yarema Bezchlibnyk, MD PhD – University of South Florida
Rationale: Vagal nerve stimulators (VNS) are an FDA approved surgical treatment for refractory epilepsy. While data supports its efficacy, there is less evidence showing whether timing from seizure onset to VNS placement affects seizure freedom, number of anti-seizure medications (ASM) and surgical morbidities.
Methods: All patients who underwent placement of a VNS at a single academic institution for medically refractory epilepsy between 2018 and 2022 were included in this retrospective study. Data was collected retrospectively via chart review with IRB approval. Primary outcomes were reduction in seizure medications and Engel scores at 1 year of follow-up, grouped into improvement (score of 1-3) or no improvement (score of 4). Secondary outcomes included mortality rates and peri/postoperative complications. Binary outcomes were analyzed using logistic regression.
Results: 116 patients were identified, and 85 had at least 1 year of follow-up and were therefore included in this study. 39 were male, 46 were female, and average age at surgery was 36 years old (range: 15-77). Average time from seizure onset to surgery was 19 years (range: 1-57). At 1 year of follow-up, 60 patients (70.6%) reported an improvement in their seizures, while 25 (29.4%) did not. However, there did not appear to be an association between time to implantation and seizure freedom (p=0.7232, OR: 0.9936; 95%CI: 0.9588-1.0296). Only 22 (25.8%) patients reduced their ASM regimen at 1 year of follow-up, which again had no association with time to implantation (p=0.8538, OR: 1.0036; 95%CI: 0.9665-1.0420). There was only 1 case (1.2%) of sudden unexplained death in epilepsy. Additionally, one patient (1.2%) had a wound infection. These patients had their VNS placed 16 and 38 years after onset of seizures, respectively. There were no other peri- or post-operative complications.
Conclusions: Based on this preliminary analysis, there is no association between time to VNS placement and rates of seizure freedom or reductions in anti-seizure medication regimens. However, this study did not compare neuropsychological outcomes and deleterious cognitive effects that may be associated with prolonged uncontrolled seizure. Our data does however reinforce the overall significant impact on seizure frequency that a VNS can have, with a large proportion of patients reporting improvement. Future studies should perform subgroup analyses by seizure types as well as explore the impact on seizure morbidity.
Funding: No funding was received for this study.
Surgery