Intraoperative Electrocorticography During Laser-interstitial Thermal Therapy Predicts Seizure Outcome in Mesial Temporal Lobe Epilepsy
Abstract number :
2.274
Submission category :
9. Surgery / 9A. Adult
Year :
2022
Submission ID :
2204814
Source :
www.aesnet.org
Presentation date :
12/4/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:26 AM
Authors :
Baibing Chen, MD, MPH – Mayo Clinic Florida; Sanjeet Grewal, MD – Neurosurgery – Mayo Clinic Florida; Erik Middlebrooks, MD – Radiology – Mayo Clinic Florida; William Tatum, DO – Neurology – Mayo Clinic Florida; Anthony Ritaccio, MD – Neurology – Mayo Clinic Florida; Joseph Sirven, MD – Neurology – Mayo Clinic Florida; Brin Freund, MD – Neurology – Mayo Clinic Florida; Feyissa Anteneh, MD – Neurology – Mayo Clinic Florida
Rationale: Laser interstitial thermal therapy (LiTT), a minimally invasive alternative to anterior temporal lobectomy for the treatment of mesial temporal lobe epilepsy (mTLE), has recently gained popularity. The role of intraoperative electrocorticography (iECoG) during LiTT of the mesial temporal lobe structures in mTLE has not been examined. In this study, we aimed to investigate the predictive value of pre and post- LiTT iECoG on seizure outcome in patients with mTLE. We hypothesized that a robust reduction in the frequency of epileptiform discharges (ED) post-LiTT compared to pre-LiTT is associated with a favorable seizure outcome.
Methods: We conducted a pilot prospective single-center cohort study on eight consecutive patients with drug-resistant mTLE. LiTT was performed using the NeuroBlate system (Monteris Medical, Minneapolis, MN) for laser energy delivery and MR thermal imaging. The laser catheter was implanted orthogonally to penetrate the central portion of the hippocampus from the body at the level of the tectal plate through the head, continuing through the amygdala to the medial temporal pole. Before LiTT, a 1x8 contact depth electrode (2mm contact length, 5 mm spacing, and 37 mm recording depth) was inserted for the pre-LiTT iECoG. Immediately after the completion of the LiTT, the depth electrode was re-implanted for the post-LiTT ECoG. The neurosurgeon was blinded to the findings of the iECoG. We have extracted clinical and surgical variables, including demographics, epilepsy history, presurgical evaluation, iECoG findings, LiTT ablation volume, and seizure freedom outcomes.
Results: The cohort's mean age was 42 years (range = 24-62); five males and three females. Six patients had left mTLE, and two patients had right mTLE. Four patients had imaging evidence of mesial temporal sclerosis (MTS), while the others were non-lesional. The mean pre-LiTT and post-LiTT ECoG durations were 5.9 minutes and 5.3 minutes, respectively. Mean follow-up duration was 26.1 months (range, 6.8-48.4). Four patients had Engel Class I (responders), one had Engle class III, and three patients had Engel Class IV outcomes (non-responders). The mean pre-LiTT ED frequencies per minute for responders and non-responders were 62.5 and 16.9, respectively (p = 0.11). The mean post-LiTT ED frequencies per minute for responders and non-responders were 8.3 and 9.3, respectively (p = 0.83). The mean percent reductions in ED frequency pre- and post-LiTT were 86% (range = 70% - 100%) in responders and 15% (range, -11% - 50%) in non-responders (p = 0.0143). Clinical variables including epilepsy duration, laterality, presence of MTS, and LiTT ablation volume were not associated with responder status.
Conclusions: Analysis of pre-and-post-LiTT iECoG during mesial temporal lobe LiTT could predict seizure outcomes in patients with mTLE. A robust reduction of ED on post-LiTT ECoG may be a favorable prognostic factor of seizure outcome in this patient population. However, larger prospective studies are needed to confirm our findings.
Funding: None
Surgery