Stereoelectroencephalography‐guided radiofrequency thermocoagulation in drug‐resistant focal epilepsy: Results from more than 20 years of experience

OBJECTIVE: This study was undertaken to present more than 2 decades of experience with stereoelectroencephalography (SEEG)-guided radiofrequency thermocoagulation (RF-TC) in focal drug-resistant epilepsy and to identify clinical, electrophysiological, and procedural predictors of treatment response. METHODS: We retrospectively studied 244 consecutive patients treated with SEEG-guided RF-TC at our center between 2001 and 2024. All had at least 2 months of follow-up, and 240 (98.4%) completed 1 year. Outcomes were assessed at 2, 6, and 12 months. The primary endpoint was seizure freedom at 2 months and 1 year without additional surgery, and the secondary endpoint was ≥50% seizure reduction. Demographic and epilepsy-, imaging-, and procedure-related variables were analyzed. RESULTS: At 2 months, 160 patients (65.6%) were responders, including 63 (25.8%) seizure-free. At 1 year, among 135 patients treated exclusively with SEEG-guided RF-TC, 64 (51.2%) were responders, including 19 (14.1%) seizure-free. At 5 years, 6.1% treated exclusively with SEEG-guided RF-TC remained seizure-free. Magnetic resonance imaging was negative in 40.6%, and focal cortical dysplasia was the most frequent imaging finding (20.1%). A higher number of contacts was associated with lower seizure-free rates at 1 year (p = .046). Pathology and electrode number were the only variables associated with 1-year outcomes. The positive predictive value of being a responder at 2 months for favorable surgical outcome was 83%, and the negative predictive value was 44%. Recoagulation within the first year was strongly associated with clinical improvement (p < .00001). Neurological complications occurred in 2.9%, including .8% permanent deficits. SIGNIFICANCE: SEEG-guided RF-TC is a safe diagnostic option with some therapeutic implication (6% seizure freedom in 5 years) for selected patients with drug-resistant focal epilepsy. Early response predicts favorable long-term outcomes, and repeated coagulation can enhance clinical results. Pathology and the number of contacts used in thermocoagulation may serve as potential prognostic factors.