Abstracts

Rationale: Retention of the mesial structures is a primary reason for surgical failures in patients wtih drug-resistant mesial temporal lobe epilepsy due to hippocampal sclerosis (HS). Laser ablation is stereotactically able to precisely identify the amygdalohippocampal complex (AHC). Ablation using real-time brain MRI is able to permit immediate information about the region of interest. We compared the post-operative completeness from laser ablation of the AHC in a cohort of patient with mesial temporal sclerosis (MTS) on pre-operative MRI. Methods: Five patients underwent a pre-surgical evaluation for drug-resistant lfocal seizures with laser ablation of the left AHC. A standard non-invasive protocol demonstrated left MTS on a 3-T brain MRI utilizing an epilepsy protocol. In all 5 patients, MRI was concordant with the remainder of the pre-surgical evaluation. Occipital-temporal laser ablation was performed as part of an IRB approved study protocol. Post-operative amygdala and hippocampal ablation at 3 months was compared wtih the pre-operative MRI. Results: Five patients (4F: 27-57 years) had left TLE due to MTS and laser ablation. A 3 month post-operative MRI was obtained in 4/5 (1/5 had reconstructed intraoperative) patients with at least 3 month followup. More than 75% of the amygdala and 100% of the head-to-tail hippocampal region was ablated in 3/5 patients. One patient had parahippocampal gyrus and the uncal recess ablated with <25% ablation of the AH. One patient had the parahippocampal gyrus and 50% of the anterior-medial hippocampus ablated with a greater T2 signal in the remaining AH. 1/5 experience a single post-operative seizure (complete ablation) and 4/5 remain seizure free. 1 patient experienced a right quadrantanopsia after surgery.Conclusions: Minimally invasive laser ablation is super-selective means to target the AH with a near perfect anatomic amygdalohippocampectomy possible. Even in cases of incomplete ablation, early seizure freedom was obtainable probably due to interruption of the HS network. Ongoing data collection is being performed.