Authors :
Presenting Author: Utku Uysal, MD – The University of Kansas Medical Center
Vishal Shah, MD – University of Kansas Medical Center
Carol Ulloa, MD – The University of Kansas Medical Center
Nancy Hammond, MD – University of Kansas Medical Center
Murtaza Khan, MD – University of Kansas Medical Center
Jennifer Cheng, MD – University of Kansas Medical Center
Michael Kinsman, MD – Kansas University School Of Medicine
Christopher Miller, MD – The University of Kansas Medical Center
Ryan Lay, MD – University of Kansas Medical Center
Margaret Logan, MD – University of Kansas Medical Center
Paul Camarata, MD – University of Kansas Medical Center
Patrick Landazuri, MD – Department of Neurology, University of Kansas Medical Center
Rationale:
Resection of the epileptogenic zone is effective treatment for patients with drug-resistant epilepsy (DRE). Many patients are not good candidates due to potential neurologic risks or limited benefits. Responsive neurostimulation (RNS) is an effective neuromodulation option for DRE. We sought to determine the efficacy and safety of cortical RNS in the treatment of patients with DRE at our center.
Methods:
A retrospective chart review was done for patients followed at the University of Kansas Medical Center and underwent RNS placement before 04/01/2024. Patients with >12 months follow-up duration were included in the final data analysis. Patients with active thalamic electrode were excluded. Collected variables include but not limited to demographics, seizure types, epilepsy type, epilepsy risk factors, neuroimaging findings, number of antiseizure medications, previous surgical interventions, location of electrode placement, complications, and seizure outcome. Descriptive statistical analysis methods were used with variables reported as mean or median for numerical variables and percentage for categorical variables. The Chi-square and Fisher’s exact tests were employed to compare independent groups for categorical variables. Results:
Out of 113 patients 68 fit the inclusion criteria. 36 patients with at least one thalamic electrode and 9 with less than 12 months follow up were excluded. 51.5% were females. The mean age was 43.8± 13 years. The mean age of seizure onset was 20.9 ± 14.4 years, and the mean age at first surgery was 39.1 ± 13.0 with a mean time from seizure onset to first surgery 16.8 ± 9.9 years. Median duration of post-RNS follow-up was 45.0 months. All patients had focal epilepsy. Unknown etiology was most common (42.6%) followed by encephalocele and encephalomalacia (7.4% each). Isolated MTS was seen in 4.4% of the patients while it was associated with encephalocele in 2.9% and MCD in 1.5%.
72.1% of patients underwent only RNS, 10.3% underwent RNS after previous resection, and 7.4% had resection following RNS. 4.4% had simultaneous resection and RNS placement. 75% had cortical, 14.7% had bilateral mesial temporal and 10.3% had combination of these locations. Achieving a state of freedom from disabling seizures in terms of Engel 1 or ILAE I/II were seen in 20.6% and 17.6% respectively when only the effect of RNS was considered. 69.7% of the patient had more than 50% reduction of baseline seizure rates (ILAE I-IV). There was no difference regarding freedom from disabling seizures in terms of Engel 1 or ILAE I/II between patients who underwent bitemporal vs neocortical electrode placement (p=0.480 and p = 1.000 respectively).
5 patients (7.4%) had complications (3 scalp infections, 1 device related infection and lead fracture, 1 patient with flap reconstruction). One patient died from glioblastoma, and one patient died from possible SUDEP unrelated to surgical intervention.
Conclusions:
Overall, our-long term data showed that cortical and/or mesial temporal RNS provides >50% seizure reduction in about 69.7% of the population seen at the University of Kansas Medical Center. The outcome from our center is comparable to the outcomes reported in the literature.
Funding: None