This is a multi-site registry study that aims to collect real-world clinical outcomes and device performance of the OneRF Ablation System. The study focuses on patients with refractory epilepsy who undergo, or are being considered for, sEEG-guided RF ablation using the OneRF Ablation System, as part of routine seizure diagnosis and treatment.

Stereoelectroencephalography (SEEG) -guided radiofrequency (RF) ablation is a minimally invasive procedure that uses thin electrodes already placed in the brain for seizure diagnosis to deliver targeted heat to destroy brain tissue associated with epileptic seizures.

The OneRF Ablation System is a device cleared by the FDA in 2023 for this treatment. Since receiving FDA clearance, the OneRF Ablation System has been used in ablation procedures in patients with seizures at multiple hospitals. Early published clinical data show a meaningful decrease in seizure burden (1). One of the key features of the device is the ability to monitor and control temperature throughout the treatment. While the advantages of real-time temperature monitoring and control are increasingly being recognized, additional clinical information would be beneficial to understand the full impact of this technology on patient outcomes.

This study is a prospective and retrospective, multicenter, observational registry. The study will take place at up to 10 sites across the United States and is expected to enroll up to 100 participants, including both adults and children. The goal of the registry is to evaluate clinical outcomes and device performance of the OneRF Ablation System.

The study will include data collection from patients with drug resistant epilepsy who are undergoing sEEG evaluation for seizure diagnosis and treatment, and:

• Have already had an ablation procedure with the OneRF Ablation System, or
• Are being considered for treatment with the OneRF Ablation System as part of their clinical seizure evaluation.

Data will be collected from patients before and throughout routine follow-up visits for up to one year after the RF ablation procedure. The study will look at seizure control, quality of life, adverse events, how the procedure is performed, and factors that may predict which patients benefit most.

Taking part in this registry does not change a patient's medical care. The study only collects information from treatments and follow-up visits that are already part of routine practice care for seizure management.

Inclusion Criteria:

1. Patients diagnosed with drug resistant epilepsy (DRE)
2. Patients who have received or will receive EVO® sEEG-RF implants
3. Patients who have undergone or may undergo an RF ablation procedure using the OneRF Ablation System.
4. Patient, or legal guardian, understands study procedures and voluntarily signs informed consent in accordance with institutional policies. In the event that the patient is under the age of 18, the patient may also be required (per IRB) to sign an assent affirming their agreement to participate.

Exclusion Criteria:

1. Any condition that, in the judgement of the clinician, would make the participant inappropriate for registry participation

Patients diagnosed with drug resistant epilepsy (DRE)