Abstracts

Rationale: MRI-guided thermal ablation is a stereotactic surgical technique utilizing laser induced heat initially employed to ablate oncological tumors. Unlike radio ablation or other minimally invasive techniques, the foci are ablated while reviewing the MRI in real time. In the field of Epilepsy, thermal ablation has been used successfully to ablate primarily mesial temporal lesions. There has been limited literature about morbidity and seizure outcome following laser ablation of neocortical lesions. Surgically removing such lesions and/or the epileptogenic zone may carry significant risk for acute and long term morbidity, especially in lesions proximal to eloquent language or motor areas or for deep lesions where normal tissue must be traversed for complete resection. Avoiding injury to normal tissue/circuits, the minimal invasive nature of the procedure, and the controlled approach of viewing the ablation in real time, provides thermal ablation the potential to revolutionize the approach to managing such lesions. In an ongoing collaboration between two pediatric epilepsy centers with extensive experience in thermal ablation, it was decided to review patients with intractable localization related epilepsy treated with MRI-guided thermal ablation of frontal lobe lesions with primary outcomes being seizure outcome and morbidity post ablation. Methods: The data of children who underwent laser ablation were placed in a shared Red Cap Database. Only patients in whom frontal lobe lesions were identified and ablated were included in the analysis. Patients with less than 3 months follow-up, MRI negative frontal ablations and Palliative ablations were excluded from analysis. Duration of epilepsy; number of AED's prior to ablation; investigative studies identifying foci and function; prior epilepsy surgeries; number of laser fibers used; duration of hospital stay; seizure outcome and acute and chronic morbidity were all addressed. Results: The Combined database revealed 21 patients with frontal lobe lesions. Seizure duration prior to ablation ranged from 1-14 years. Follow up ranged from 3-30 months. 16/21 (76%) had rare seizures or were seizure free (Engels 1or 2). Maximal amount of fibers used were 2. Most patients were diagnosed with Cortical Dysplasia with a Cavernoma and two low grade tumors also ablated. No patients had long term morbidity. Neuropsychology follow-up was completed 6 months to one year post ablation and is ongoing. Conclusions: This now, novel technique has afforded patients removal of epileptiform foci with decreased morbidity. In patients with MRI positive lesions, Laser ablation was found to be as successful as the literature suggests in traditional surgical removal of lesions. Longer term follow-up is required. Also further neurocognitive follow-up is required to determine potential benefits. Funding: None