215 Laser Thermal Ablation for Mesiotemporal Epilepsy

Abstract

Abstract INTRODUCTION Laser interstitial thermal therapy (LiTT) has dramatically changed the management of mesiotemporal epilepsy (mTLE) in recent years. The goal of this study was to identify features of ablations and trajectories that correlate with optimal seizure control and minimize the risk of neurocognitive deficits in patients undergoing LiTT for mTLE. METHODS Clinical and radiographic data were reviewed from a prospectively maintained database of patients undergoing LiTT for epilepsy at the University of Miami. Standard preoperative and postoperative evaluations, including contrast-enhanced MRI and neurocognitive testing, were performed in all patients. Laser trajectory and ablation volumes were computed both by manual tracing of mesiotemporal structures and by nonrigid registration of ablation cavities to a common reference system based on 7T MRI data. RESULTS >Of the 28 patients with at least 1-year follow-up, sparing of the mesial hippocampal head was significantly correlated with persistent disabling seizures (P = 0.01). Projecting all ablation cavities onto a common reference frame showed a clear tendency towards lateral placement of the laser with inadequate mesial hippocampal head ablation in these patients compared to those free of seizures. Patients that suffered deficits in memory, on the other hand, tended to have larger ablations with greater insult to entorrhinal and perirhinal cortex than those free of memory deficits. CONCLUSION Better understanding of the impact of ablation volume and location through the use of image normalization tools could potentially fine-tune this novel technique to improve seizure-freedom rates and associated neurocognitive deficits.