Laser interstitial thermal therapy for medically intractable mesial temporal lobe epilepsy

<jats:title>Summary</jats:title><jats:sec><jats:title>Objective</jats:title><jats:p>To describe mesial temporal lobe ablated volumes, verbal memory, and surgical outcomes in patients with medically intractable mesial temporal lobe epilepsy (<jats:styled-content style="fixed-case">mTLE</jats:styled-content>) treated with magnetic resonance imaging (<jats:styled-content style="fixed-case">MRI</jats:styled-content>)–guided stereotactic laser interstitial thermal therapy (Li<jats:styled-content style="fixed-case">TT</jats:styled-content>).</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>We prospectively tracked seizure outcome in 20 patients at Thomas Jefferson University Hospital with drug‐resistant m<jats:styled-content style="fixed-case">TLE</jats:styled-content> who underwent <jats:styled-content style="fixed-case">MRI</jats:styled-content>‐guided Li<jats:styled-content style="fixed-case">TT</jats:styled-content> from December 2011 to December 2014. Surgical outcome was assessed at 6 months, 1 year, 2 years, and at the most recent visit. Volume‐based analysis of ablated mesial temporal structures was conducted in 17 patients with mesial temporal sclerosis (MTS) and results were compared between the seizure‐free and not seizure‐free groups.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Following Li<jats:styled-content style="fixed-case">TT</jats:styled-content>, proportions of patients who were free of seizures impairing consciousness (including those with auras only) are as follows: 8 of 15 patients (53%, 95% confidence interval [<jats:styled-content style="fixed-case">CI</jats:styled-content>] 30.1–75.2%) after 6 months, 4 of 11 patients (36.4%, 95% <jats:styled-content style="fixed-case">CI</jats:styled-content> 14.9–64.8%) after 1 year, 3 of 5 patients (60%, 95% <jats:styled-content style="fixed-case">CI</jats:styled-content> 22.9–88.4%) at 2‐year follow‐up. Median follow‐up was 13.4 months after Li<jats:styled-content style="fixed-case">TT</jats:styled-content> (range 1.3 months to 3.2 years). Seizure outcome after Li<jats:styled-content style="fixed-case">TT</jats:styled-content> suggests an all or none response. Four patients had anterior temporal lobectomy (<jats:styled-content style="fixed-case">ATL</jats:styled-content>) after Li<jats:styled-content style="fixed-case">TT</jats:styled-content>; three are seizure‐free. There were no differences in total ablated volume of the amygdalohippocampus complex or individual volumes of hippocampus, amygdala, entorhinal cortex, parahippocampal gyrus, and fusiform gyrus between seizure‐free and non–seizure‐free patients. Contextual verbal memory performance was preserved after Li<jats:styled-content style="fixed-case">TT</jats:styled-content>, although decline in noncontextual memory task scores were noted.</jats:p></jats:sec><jats:sec><jats:title>Significance</jats:title><jats:p>We conclude that <jats:styled-content style="fixed-case">MRI</jats:styled-content>‐guided stereotactic Li<jats:styled-content style="fixed-case">TT</jats:styled-content> is a safe alternative to ATL in patients with medically intractable mTLE. Individualized assessment is warranted to determine whether the reduced odds of seizure freedom are worth the reduction in risk, discomfort, and recovery time. Larger prospective studies are needed to confirm our preliminary findings, and to define optimal ablation volume and ideal structures for ablation.</jats:p></jats:sec>