Intraoperative electrocorticography during laser-interstitial thermal therapy predicts seizure outcome in mesial temporal lobe epilepsy

Abstract

Objective: Magnetic resonance-guided laser interstitial thermal therapy (MRLiTT) for treating temporal lobe epilepsy has recently gained popularity. We aimed to investigate the predictive value of pre-and post-MRLiTT epileptiform discharges (EDs) on intraoperative electrocorticography (iECoG) in seizure outcomes for patients with mesial temporal lobe epilepsy (mTLE).

Methods: We conducted a pilot, prospective single-center cohort study on seven consecutive patients with mTLE that underwent MRLiTT. Pre- and post-MRLiTT iECoG was performed using a 1x8 contact depth electrode along the same trajectory used for the laser catheter.

Results: The responders had a robust reduction in ED frequency compared to pre-MRLiTT iECoG (86% vs 13%, p < 0.01). Clinical characteristics, including risk factors for epilepsy, duration of epilepsy, presence of mesial temporal lobe sclerosis, prior intracranial monitoring, the absolute frequency of pre- or post-MRLiTT EDs, and ablation volume were not significantly associated with responder status.

Conclusions: This is the first demonstration that intraoperative reduction in EDs during mesial temporal lobe MRLiTT may potentially predict seizure outcomes and may serve as an intraoperative biomarker for satisfactory ablation. However, larger prospective studies are needed to confirm our findings and evaluate the utility of iECoG during MRLiTT.

Significance: iECoG during mesial temporal lobe MRLiTT may help assess seizure outcomes.

Keywords: Drug-resistant epilepsy; EEG; Electroencephalogram; Focal epilepsy; Laser ablation; Seizure freedom; Temporal lobe epilepsy.