Abstracts

Rationale: Open anterior temporal lobectomy with amygdalohippocampectomy is the gold standard treatment for drug resistant mesial temporal lobe epilepsy (MTLE), however surgical resections are associated with cognitive and neurological deficits. Stereotactic laser ablation with magnetic resonance guidance allows real-time thermal monitoring and precise obliteration of the amygdalohippocampal complex (AHC). We report clinical outcomes in a cohort of patients with MTLE who received stereotactic laser ablation of AHC and quantified change in the volume of AHC on pre- and post-operative MRI to correlate the volume of AHC ablation to efficacy of post-operative seizure control. Methods: Eleven patients underwent pre-surgical evaluation for drug-resistant focal epilepsy by a multidisciplinary team including epileptologists, neurosurgeons, neuropsychologistist and neuroradiologist. A 3-T brain MRI demonstrated abnormality in 10/11 patients. One patient with normal MRI had seizures coming from left mesial temporal lobe recorded by depth electrodes. All eleven patients underwent stereotactic laser ablation of mesial temporal structures with real time magnetic resonance guidance as part of an IRB approved study protocol. All pre- and post-operative brain MRIs were reviewed by two board-certified neuroradiologists who independently graded the volume of AHC ablation. Results: Eleven patients (5F: 20-68 years) with MTLE received laser ablation after multi-disciplinary evaluation. A 3-Tesla MRI using seizure protocol was obtained in all patients except for one patient whose ablation volume was analyzed using intra-operative iMRI images. Mean volume of ablation for amygdala, head of hippocampus and body of hippocampus in 11 patients were: 52%, 74.5% and 78.2%, respectively. Median follow-up was 12 months (range: 5 to 18 months). All but one patient (91%) remained free of continued epilepsy post-operatively. Six patients (55%) experienced seizures in the postoperative period, which were controlled with adjustments of anti-seizure medications. Nine out of 10 patients with MTS remained seizure free at the latest follow-up. There were no significant neurological deficits except for one patient who experienced right quadrantanopia post-operatively. Conclusions: Laser ablation of the AHC is able to achieve long-term seizure freedom without significant morbidity. Volumetric evaluation demonstrated the ability to obtain hippocampal ablation in > 75% of the head and body. While early seizures were observed they were easily controlled with medication adjustment. Ongoing data collection is being performed to evaluate long-term efficacy and safety.