204 Anatomical Modeling of Two-Trajectory Laser Amygdalohippocampotomy

Abstract

INTRODUCTION: Laser interstitial thermal therapy (LITT) for mesial temporal lobe epilepsy (mTLE) is typically performed with one laser trajectory to target the medial temporal lobe (MTL). MTL structures such as piriform and entorhinal cortex are epileptogenic, but due to their relative geometry, are difficult to target with one trajectory while simultaneously maintaining adequate ablation of the amygdala and hippocampus. METHODS: Magnetic resonance imaging (MRI) from the Human Connectome Project (HCP) was used to create subject-specific target structures consisting of hippocampus, amygdala, and piriform/entorhinal/perirhinal cortex. An algorithm searched for safe potential trajectories along the hippocampal axis (catheter one) and along the amygdala-piriform axis (catheter two) and compared this to a single trajectory optimized over all structures. The proportion of each structure ablated at various burn radii was evaluated. A cohort of 11 consecutive patients with mTLE received two laser LITT. RESULTS: The two-laser trajectory approach was superior at nearly all burn radii for all hippocampal subfields and amygdala nuclei (p < 0.05). Two-laser trajectories achieved full ablation of MTL cortical structures at physiologically realistic burn radii, while one-laser trajectories could not. 5 patients with at least 1 year follow-up (mean = 21.8 months) experienced Engel class I outcomes; 6 patients with less than 1 year follow-up (mean = 6.6 months) are on track for Engel I outcomes. CONCLUSION: Large-scale artificial intelligence search through high-quality HCP imaging data reveals the theoretical advantage of two-laser LITT over one-laser LITT.