Authors :
Presenting Author: Michael Staudt, MD, MSc – UH Cleveland Medical Center
Jonathan Zande, MD – UH Cleveland Medical Center
Brin Freund, MD – Mayo Clinic Florida
William Tatum, MD – Mayo Clinic Florida
Anteneh Feyissa, MD – Mayo Clinic Florida
Seyed Mirsattari, MD, PhD – Mayo Clinic Florida
Sanjeet Grewal, MD – Mayo Clinic Florida
Rationale:
In patients with drug resistant epilepsy (DRE), stereo-electroencephalography (sEEG)-guided radiofrequency ablation (RFA) allows diagnosis and treatment within one procedure. The ability to continue post-RFA recordings may also yield information on treatment efficacy and prognosis. Until recently, electrodes did not provide control of temperature during RFA, which could impact efficacy. Here we describe the first-in-human use of a new FDA cleared sEEG-guided RFA system with real-time monitoring and controlling of ablation temperature and time.
Methods:
Three patients from two level 4 epilepsy centers underwent sEEG implantation and subsequent RFA. Patient 1 is a 27F with extensive periventricular nodular heterotopia (PVNH). Scalp EEG demonstrated right hemispheric seizures, consisting of tonic motor activity and tachycardia. Patient 2 is an 18F with non-lesional epilepsy and hypermotor seizures occurring exclusively during sleep. Ictal EEG was non-localizing or lateralizing. Patient 3 is a 28M status-post bitemporal responsive neurostimulator (RNS) implantation. His seizures consisted of pilomotor erection, often followed by loss of awareness and generalized tonic-clonic activity, primarily from the dominant left hippocampus. All patients were discussed at a multidisciplinary epilepsy conference. Patients 1 and 2 underwent bilateral implantation of 13 and 12 electrodes, respectively. Patient 3 underwent explant of the left RNS lead followed by implantation of 5 electrodes (2 longitudinal, 3 orthogonal) into the left hippocampus.
Results:
All ablations were performed at bedside using bipolar, temperature control modes (85°C, 2-5 minutes). Electrical stimulation was performed in all patients prior to ablation. MRIs were obtained following electrode explant. Patient 1 demonstrated seizure onset in the posterior aspect of each PVNH. Four RFAs were performed in the PVNH, left posterior temporal and right frontal neocortices. She was seizure-free at 16 days follow-up. Patient 2 demonstrated seizure onset in the right anterior insula with rapid bilateral spread to the anterior cingulate. RFA was performed in the right anterior insula, bilateral anterior cingulate. She continued to have electroclinical seizures, and repeat anterior insula RFA was performed 4 days later without recurrence. MRI demonstrated lesion sizes of 7-8 mm in both patients. Patient 3 had typical seizures arising from the hippocampal head and body. RFA was performed over two sessions, 24h apart: 42 total ablations were performed across contiguous contacts and between electrodes to mimic multiple hippocampal transections. MRI demonstrated large confluent lesions along the ablated trajectories (1-2.3 cm). At 2 months follow-up, he is seizure-free with improved mood and memory. The procedure was well-tolerated in all patients with no adverse effects.
Conclusions:
sEEG-guided RFA with real-time temperature control is feasible, safe and well-tolerated. Previous ablations with off-the-shelf components lacked thermocoupling and resulted in unpredictable lesion size and configuration. Temperature and time control with real-time monitoring of RFA parameters is intuitive and allows for controllable lesion creation.
Funding: None