Technique, safety profile, and seizure outcomes after laser ablation for insular epilepsy: a multicenter cohort study

OBJECTIVE: The objective of this study was to assess the incidence of complications and seizure outcomes of laser interstitial thermal therapy (LITT) in the treatment of drug-resistant insular epilepsy, with a specific focus on complication rates after ablation of the posterior insula. METHODS: The authors retrospectively analyzed the diagnostic workup and outcomes of all patients treated with LITT for the treatment of insular epilepsy at three centers. The hypothesis of insular origin was based on a combination of semiology, MRI, and FDG-PET/CT and/or magnetoencephalography in MRI-negative cases. Twelve of 14 patients underwent stereoelectroencephalography (SEEG), in which 3 patients underwent radiofrequency thermocoagulation following SEEG. Additionally, 2 patients underwent a secondary LITT procedure. RESULTS: Following LITT, 9 patients (64.3%) achieved complete seizure freedom (International League Against Epilepsy [ILAE] class 1), 2 (14.3%) achieved seizure freedom but retained auras (ILAE class 2), and 3 (21.4%) saw no improvement in their epilepsy (ILAE class 5) at 6 months' follow-up. The patients who underwent a secondary LITT procedure achieved ILAE class 1 and 5, respectively. The overall transient complication rate was 18.8% for all 16 LITT cases and 21.4% for the 14 procedures that included ablation of the posterior insula. The permanent complication rate was 6.3% for all 16 LITT cases and 7.1% for 14 procedures that included ablation of the posterior insula. CONCLUSIONS: LITT is a safe and effective intervention for controlling insular epilepsy. Although the study is limited by its relatively short follow-up period, the seizure freedom rate observed in this cohort is comparable to that following open insular resection, with a low incidence of complications.