Authors :
Presenting Author: Aura Kullmann, PhD – NeuroOne
Mary McNeil, MS – NeuroOne; Maria Porto Cruz, PhD – NeuroOne; Robert Gross, MD/PhD – Emory University; Vishwadeep Ahluwalia, PhD – Georgia Institute of Technology; Su-Youne Chang, PhD – Mayo Clinic Rochester; Inyong Kim, PhD – Mayo Clinic Rochester; Hijaz Haris, MS – NeuroOne; Steve Mertens, MS – NeuroOne; Debra Kridner, BS – NeuroOne; Sam Ong, BS – NeuroOne; Filip Mivalt, MS – Mayo Clinic Rochester; Gregory Worrell, MD/PhD – Mayo Clinic Rochester; Jamie Van Gompel, MD – Mayo Clinic Rochester; Dave Rosa, MS – NeuroOne; Maria Vomero, PhD – NeuroOne; Camilo Diaz-Botia, PhD – NeuroOne
Rationale: Stereoelectroencephalography (sEEG) combined with radiofrequency (RF) ablation is a procedure in which the sEEG electrodes implanted for seizure evaluation are also used for lesioning the tissue.
This is accomplished by delivering electric current at high frequency (above 250 kHz), to raise the temperature between the active contacts sufficiently to destroy at least a portion of the epileptogenic zone. The procedure has been shown to reduce seizure frequency with minimal risks.
Currently, the temperature at which sEEG-guided RF ablations are performed cannot be monitored. This study uses an in vivo swine model to evaluate a new RF ablation system. This system uses FDA-cleared sEEG electrodes equipped with a unique temperature control accessory designed to monitor and maintain the temperature at which ablations are performed.
Methods: sEEG electrodes (n=13) were implanted into the brain of two pigs. In one animal sEEG positioning was verified using CT scan. RF energy was delivered for specific durations (30-300s) and temperatures (50-90°C) in monopolar and bipolar (between two adjacent sEEG contacts) configurations. Lesions were assessed using MRI and histology. Impedance measurements were performed pre- and post-ablation.
Results: Lesions were identified in MRI scans and histology as spherical (monopolar) or ellipsoidal shape (bipolar). For most lesions, size was proportional to temperature and time. Histological examination of pig brain tissue showed a necrotic center surrounded by a ring of pallor composed of neuropil vacuolation and intramyelinic edema (n=4 ablations). The adjacent neural tissue was intact. Comparison of sEEG impedance pre- and post-ablation indicated that continuation of electrophysiological recordings is feasible.
Conclusions: This innovative sEEG-guided RF ablation system delivered clinically relevant RF energy to ablate porcine brain in vivo. The system offers several advantages, including ability to precisely monitor and regulate temperature during the ablation, ability to continue intracranial sEEG recordings pre and post ablation, and potential to reduce the number of surgical procedures by providing treatment using the same electrodes used for diagnostic purposes.
Funding: NeuroOne Medical Technology Corporation.