Seizure outcomes of laser interstitial thermal therapy (LITT) for drug-resistant extratemporal epilepsy

Magnetic resonance image-guided laser interstitial thermal therapy (LITT) is a minimally invasive alternative to surgical resection for the treatment of drug-resistant epilepsy (DRE). Seizures arising outside of the temporal lobe can be difficult to treat due to the heterogeneity of anatomical locations and underlying pathologies. The effectiveness of LITT ablations for extratemporal lobe epilepsy (ETLE) is not well established.

We retrospectively reviewed subjects with DRE who underwent extratemporal LITT at a single institution from 2015 to 2021. Our primary outcomes were Engel classification and reduction in baseline seizure frequency at last follow-up. Our secondary outcome was postoperative complications.

Nine subjects were included. The mean age at LITT was 29.6 years and 66% (n = 6) were male. Mean follow-up was 35 months. Engel Class I outcomes were achieved in 78% (n = 7) with complete seizure freedom (Class IA) in 66% (n = 6). Engel Class III outcomes were achieved in the remaining 22% (n = 2) with worthwhile improvements to seizure activity. Two years after ablation, 78% (n = 7) of subjects experienced >90% reduction of seizures from baseline while 11% (n = 1) experienced >50% reduction from baseline. Further, 33% (n = 3) had reduction in antiseizure medications (ASMs). Postoperative complications were experienced in 22% (n = 2) and both were transient.

In our study of subjects with ETLE who underwent LITT for DRE, 78% achieved >90% reduction of seizure frequency from baseline and 78% of patients achieved a successful Engel Class I outcome after a mean follow-up of 35 months. We demonstrate LITT ablation is a safe and effective method of treatment for drug-resistant ETLE and may be considered even with heterogeneous etiologies or prior surgeries.