Abstracts

Rationale: sEEG-guided RFA uses sEEG electrodes implanted for seizure evaluation to create tissue lesions. The procedure has been performed in Europe for >20 years and has shown to result in seizure free or reduction of seizure frequency with minimal risks¹. Traditionally the procedure has been performed by connecting the sEEG to a power generator and ablating without monitoring the temperature. The FDA recently cleared a system capable of monitoring and controlling the ablation temperature in real time. Here we characterize lesions performed with this new system in ex vivo and in vivo.

Methods: Ex vivo lesions were performed in chicken breast tissue. In vivo lesions were performed in swine brain (34 lesions in 3 animals) and characterized by MRI and histology. Ablations were performed at various temperatures and times (70-90°C, 30-600s) in monopolar and bipolar (between two adjacent electrodes) configurations.


Results: In both systems, lesions were uniform and clearly defined in the tissue. Lesion size was proportional to temperature and time and comparable between ex vivo and in vivo, with volumes ranging from ~50-350 mm³ and ~100-400 mm³ for monopolar and bipolar lesion, respectively. For a given set of RFA parameters, lesions were highly reproducible. Histological examination of swine brain tissue showed necrotic core tissue surrounded by neuropil vacuolation and intramyelinic edema. The adjacent neuroparenchyma was intact.

Conclusions: Lesions obtained in ex vivo and in vivo tissues with the new temperature-controlled sEEG-guided RFA system were similar in appearance and size. These results support the translation to in vivo use in patients and provide guidance for ablation parameters necessary to create specific lesion sizes.

Funding: NeuroOne Medical Technology Corporation