Introduction: MRI-guided stereotactic laser amygdalohippocampotomy (SLAH) is a minimally invasive and effective alternative to open temporal lobe surgery in appropriately selected patients. We have previously demonstrated SLAH to be most effective for patients with mesial temporal sclerosis (MTS) on preoperative MRI. Nevertheless, patients who fail to achieve seizure freedom may benefit from additional procedures. The feasibility, safety, and efficacy of repeat laser ablation of remaining mesial temporal structures have not been reported.

Methods: A prospective cohort of 41 patients with mesial temporal lobe epilepsy, including patients with and without MTS, underwent SLAH at our institution. Patients that did not maintain seizure freedom underwent repeat MRI to reevaluate extent of ablation. Of these, 5 subjects (3 with and 2 without preoperative MTS) underwent a second procedure extending the ablation of extra-hippocampal mesial temporal structures (e.g. amygdala, entorhinal cortex, parahippocampal gyrus) and underwent routine clinical follow up.

Results: Extended extra-hippocampal temporal lobe ablations were performed from posterior temporal/occipital trajectories with 1-3 independent trajectories. Repeat procedures were well tolerated, there were no significant hemorrhages or other complications, and all patients were discharged within 1-2 days. At mean follow up of 6.2 (median 4, range 2-12) months, all 5 subjects were seizure free following extended ablation.

Conclusions: While SLAH alone is effective for select patients with mesial temporal lobe epilepsy, this preliminary study indicates that additional extended ablation of extra-hippocampal mesial temporal structures may provide additional relief from recurrent seizures. Additional subjects, longer outcomes, and neurocognitive assessments are pending.

Patient Care: This study will improve patient care by advancing a safe, effective, and minimally invasive laser therapy for epilepsy.

Learning Objectives: By the conclusion of this session, participants should be able to recognize the possible role of extended mesial temporal lobe ablations for recurrent seizures following laser amygdalohippocampotomy.

References: Willie JT, et al. Real-Time Magnetic Resonance-Guided Stereotactic Laser Amygdalohippocampotomy for Mesial Temporal Lobe Epilepsy. Neurosurgery. 2014. 74(6):569-585.