Abstracts

Rationale: Patients are deemed not to be Epilepsy Surgery candidates if they are multifocal, generalized and when, except in defined syndromes or acute circumstances, surgery would significantly impair function. MRI guided thermal ablation offers a new and relatively safe way of targeting the epileptiform focus yet minimizing risk of functional impairment. We describe 10 patients, most of whom had regions of cortical dysplasia, who were all thermally ablated successfully. Ablating multiple sites in some individuals, ablating sites embedded in eloquent cortex and ablating the insular cortex make this cohort somewhat unique. Stereo-electroencephalography (SEEG) was done in most patients. Methods: The epilepsy surgical database was reviewed for patients who had their lesions thermally ablated from January 2013 to present. Age of onset, underlying diagnosis, duration of epilepsy, prior and present AED's, prior epilepsy surgery, scalp EEG distribution of onset, SEEG, Region ablated, Neuropsychological testing pre-ablation (post ablation follow-up from 6 months to a year) and Engle outcome were all reviewed. Results: Thermal Ablation was carried out in 10 of 57 individuals who had epilepsy surgical procedures (excluding VNS and CC). Phase one evaluations were completed in all and several required further localization, laterality or determination of eloquent cortex. Eight patients had one or multiple regions of cortical dysplasia thermally ablated and two MTS ablated. Two palliative ablations were carried out. One palliative case of MTS had a known chromosomal deletion, multifocal discharges, focal seizures and occasional generalized seizure types. The other Palliative case had genetically confirmed Tuberous Sclerosis and a prior left frontal resection. He presented with right frontal events and after a phase two evaluation, had ablation of two frontal tubers. Sixty percent (6/10) of the patients had SEEG prior to the identification and ablation of between one and three active sites. Neuropsychological testing was completed on eight patients, with a mean FSIQ of 89, mean VIQ of 92, and mean PIQ of 89. One patient was too young for IQ testing, but developmental testing revealed cognitive performance in the average range (SS = 93). Follow-up testing is ongoing. Eight patients were seizure free and the two palliative cases had greater than 90% and greater than 75% reduction respectively. One patient staying longer than 24 hours and all others were discharged within 24 hours. Conclusions: Surgical options would traditionally not be offered in our cases of bilateral lesions and onset, and/or onset in areas containing or in close proximity to eloquent cortex. All of our patients had successful ablations with little to no morbidity and great surgical outcome thus far. SEEG guided the extent and number of ablations in 60%. Thermal ablation could potentially be life altering for some individuals in whom surgery resection is not an option and may negate significant morbidity in others.