Authors :
Presenting Author: Hellen Kreinter, MD – Western University
Jorge Burneo, MD – Epileptologist, CNS, Western University; David Diosy, MD – Epileptologist, CNS, Western university; Michelle-lee Jones, MD – Epileptologist, CNS, Western university; Jonathan Lau, MD – Epilepsy Neurosurgeon, CNS, Western university; Keith MacDougall, MD – Epilepsy Neurosurgeon, CNS, Western university; Sonia Mejia, MD – clinical neurosurgery epilepsy fellow, CNS, Western university; Seyed Mirsattari, MD – Epileptologist, CNS, Western university; David Steven, MD – Epilepsy Neurosurgeon, CNS, Western university; Ana Suller-Marti, MD – Epileptologist, CNS, Western university
Rationale:
Radiofrequency thermocoagulation (RF-TC) is a minimally invasive procedure used for the treatment of focal, therapy-resistant epilepsy (DRE). RF-TC takes place prior to a standard epilepsy resective surgery. In previous studies, RF-TC has shown a reduction of seizures by ≥50% in 50% of patients at one year with few and minor complications. To our knowledge, there are no studies that analyze outcomes depending on whether the ablation involved: only the seizure onset zone, the seizure onset zone plus the early propagation zone, or other distant but involved zones (late propagation, distant lesion). This information will aid in the planning of the most effective way to disrupt the epileptogenic network.
Methods:
Consecutive adult patients with DRE who underwent SEEG implantation from October 2018 to April 2023, admitted to the Epilepsy Monitoring Unit, and who underwent RF-TC, were included. The following data was collected and analyzed: demographics, age of seizure onset, presurgical investigation, SEEG evaluation, cortical stimulation, RF-TC (number of contacts ablated, location of the ablation, zone within the epileptogenic network ablated, lesion ablated, complications), type of resective surgery (if completed), and epilepsy surgery outcomes.
Results:
Forty-four patients underwent depth electrode implantation. Thirteen met the inclusion criteria. The mean age at implantation was 42 years (SD 13.9); 53% were female (n=7). The most frequent location of the epileptogenic zone was the insula in 30% (n=4) followed by temporal plus insula in 23% (n=3) and then multifocal in 15% (n=2). Seven patients had only RF-TC and six underwent resective surgery either before or after RF-TC. In those patients, the epileptogenic zone was either multifocal or regional. The region of the ablation was in the insula in 46% (n=6) of the patients and involved more than one lobe in 23% (n=3). The mean number of contacts ablated was eight (SD 5.7). Ablation of contacts involved in the seizure onset zone was done in 69% (n=9), while in 30% (n=4) not all contacts involved in the seizure onset were included in the ablation (partial ablation). The early spread zone was involved in the ablation in 38% (n=5). No ablation was performed for late propagation or for another independent seizure focus. Seizure freedom at one month post RF-TC was seen in 61% (n=8/13), at six months 23.1% (n=3/11) and at twelve months 15% (n=2/8). At one and six months, the seizure freedom rates following RF-TC of all the contacts involved in the seizure onset zone were 87% (n=7) and 100% (n=3), respectively (p=0.217 and p=0.491). In contrast, ablating both the seizure onset zone (either completely or partially) and the early onset zone resulted in a seizure freedom rate of 37% (n=3) at one month. No patients achieved seizure freedom at six months (p=1.00 and p=0.491 respectively). No complications were identified.
Conclusions:
A complete ablation of the contacts involved in the seizure onset zone was associated with better outcome, whereas the inclusion of the early spread did not yield to any notable difference in outcome.
Funding: No founding was received.