Direct MRI-guided stereotactic radiofrequency thermal ablation for mesial temporal lobe epilepsy: illustrative cases

BACKGROUND Despite rapid adoption among many epilepsy centers across the United States, stereotactic magnetic resonance imaging (MRI) thermometry–guided laser interstitial thermal therapy (LITT) is not universally available to treat medically refractory epilepsy in appropriately selected patients. OBSERVATIONS The authors present two cases in which patients with mesial temporal lobe epilepsy (MTLE)—one with stereoelectroencephalography-proven left MTLE and one with right mesial temporal sclerosis—were advised to undergo LITT by a multidisciplinary team, but an insurance provider refused preauthorization, prompting the use of radiofrequency ablation (RFA) instead. In each case, the authors utilized a disposable direct MRI guidance stereotactic frame and a commercially available RFA probe with direct thermistor measurements under general anesthesia. The hippocampus, amygdala, subiculum, and entorhinal cortex were targeted with two sequential trajectories through a single occipital twist drill hole, direct MRI guidance of trajectory control, and anatomical MRI between trajectories to judge ablation progress. No complications were observed. Patients were seizure free at the last follow-ups of 11 and 24 months. Two approximately parallel RFA trajectories yielded postablation volumes comparable to index single-trajectory LITT cases. LESSONS In select cases, RFA can provide an alternative to LITT for treating focal epilepsy.