Abstracts

Rationale: Mesial temporal lobe epilepsy (MTLE) patients commonly remain refractory to medication, despite optimal treatment, and surgical intervention often offers the best chance of seizure freedom. Common surgical modalities include invasive procedures for resection of seizure foci, where seizure freedom can be achieved in 70-80% of cases. Complications associated with these strategies include visual deficit, cognitive deficit, memory and verbal deficits, and stroke. Minimally invasive techniques may be adapted and employed for effective treatment of this disabling condition with faster and less painful recovery, fewer complications, and similar or improved outcomes. However, as in planning standard surgical techniques, accurate localization of seizure foci is critical for optimal outcomes from minimally invasive techniques. Here we report for the first time the use of intracranial electrodes for seizure localization subsequently treated with minimally-invasive MR-guided laser interstitial thermal therapy for refractory right MTLE.Methods: A 50 y/o female presented with a history of adult-onset simple and complex partial seizures with and without secondary generalization. Seizures consisted of an altered sensorium with visual distortion of objects, transient disturbances of consciousness and verbalization, and impaired consciousness. Inpatient EEG monitoring initially indicated a bitemporal origin, though subsequent evaluation captured multiple events which revealed partial seizures with right temporal onset and bilateral frontotemporal involvement. PET-EEG indicated left temporal slowing suggestive of left cortical dysfunction. MRI of the brain revealed no gross structural abnormalities. As a result of these conflicting extracranial localizations, intracranial monitoring was indicated. Placement of intracranial grids over the right temporal and frontal cortices as well as placement of depth electrodes into the right amygdala and hippocampus was performed. Monitoring revealed the focus to be limited to the amygdalohippocampal complex exclusive of cortical structures. After positive localization, we used MR-guided laser interstitial thermal therapy for minimally-invasive ablation of the seizure focus in the right amygdalohippocampal complex. Results: The patient tolerated the procedure well and was discharged on postoperative day 2 without complication. In 2 months of followup, no visual field cuts or focal neurologic deficits have been appreciated. She has reported no stereotypic seizure events since surgery and has had no postoperative complications.Conclusions: In cases where intracranial monitoring is indicated due to disconcordant extracranial localization, lack of structural abnormalities, or conflicting results, invasive monitoring coupled with MR-guided laser interstitial thermal therapy has the potential to provide an effective, minimally-invasive alternative to more conventional techniques for the surgical treatment of medically refractory mesial temporal lobe epilepsy.