Seizure outcomes after laser interstitial thermal therapy for pediatric extratemporal lobe epilepsy

Approximately one-third of patients with epilepsy develop drug-resistant epilepsy (DRE). Extratemporal lobe epilepsy (ETLE) represents 30%-40% of focal epilepsy cases. ETLE poses significant challenges in localization and treatment because these patients often have diffuse and complex epileptogenic networks. Laser interstitial thermal therapy (LITT) has emerged as a minimally invasive alternative for localizable DRE, yet data for its use in the pediatric ETLE population remain limited. This study aimed to evaluate the safety and efficacy of LITT in pediatric ETLE and identify predictive factors for favorable seizure outcomes.

This retrospective study reviewed pediatric patients who underwent LITT for ETLE at a single National Association of Epilepsy Centers level 4 epilepsy center from 2015 to 2023. Patients with prior LITT for temporal lobe epilepsy, hypothalamic hamartomas, or corpus callosotomies were excluded. Preoperative evaluations included noninvasive testing (e.g., video-EEG, MRI, PET, magnetoencephalography) and invasive monitoring with stereo-EEG. The primary study endpoints were 1) International League Against Epilepsy (ILAE) classification at 12 months after the index LITT or additional surgical intervention for the treatment of seizures, and 2) procedure-related complications. Secondary analyses examined imaging concordance with the final ablation location, total ablation volume, and perioperative metrics.

Twenty-nine patients underwent an index LITT procedure for ETLE. At 12 months, 14 patients (48.3%) achieved a good outcome (ILAE class 1-3), and 12 (41.4%) were seizure free (ILAE class 1). There were 6 patients (20.7%) who required additional surgery within 12 months. Concordant PET with the final LITT ablation volume independently predicted seizure outcome (p = 0.04). The total ablation volume ranged from 0.66 to 8.45 cm3, and was not statistically different between groups. In the perioperative period, 3 patients developed transient steroid-responsive LITT-related edema, while no permanent neurological deficits, hematomas, surgical site infections, or deaths occurred.

This study demonstrated that LITT is a safe and effective treatment option for pediatric ETLE and may achieve acceptable rates of seizure freedom with a minimally invasive approach. Concordance between noninvasive imaging (particularly PET) with LITT targets was associated with favorable outcomes, underscoring the importance of thorough preoperative evaluations to determine appropriate ablation candidates. Future multicenter prospective studies are warranted to further refine patient selection criteria and optimize treatment paradigms.