MR-guided laser interstitial thermal therapy for pediatric drug-resistant lesional epilepsy

To report the feasibility, safety, and clinical outcomes of an exploratory study of MR-guided Laser Interstitial Thermal Therapy (MRgLITT) as a minimally invasive surgical procedure for the ablation of epileptogenic foci in children with drug-resistant, lesional epilepsy.

Retrospective chart review of all MRgLITT procedures at a single tertiary care center. All procedures were performed using a U.S. Food and Drug Administration (FDA)-cleared surgical laser ablation system (Visualase Thermal Therapy System). Predefined clinical and surgical variables were extracted from archived medical records.

Seventeen patients underwent 19 MRgLITT procedures from May 2011 to January 2014. Mean age at seizure onset was 7.1 years (range 0.1-14.8 years). Mean age at surgery was 15.3 years (range 5.9-20.6 years). Surgical substrates were mixed but mainly composed of focal cortical dysplasia (n = 11). Complications occurred in four patients. Average length of hospitalization postsurgery was 1.56 days. Mean follow-up was 16.1 months (n = 16; range 3.5-35.9 months). Engel class I outcome was achieved in seven patients (7/17; 41%), Engel class II in one (1/17; 6%), Engel class III in three (3/17; 18%), and Engel class IV in six (6/17; 35%). Three patients (3/8; 38%) with class I and II outcomes and five patients (5/9; 56%) with class III and IV outcomes had at least one prior resection. Fisher's exact test was not statistically significant for the association between Engel class outcome and previous resection (p = 0.64).

This study provides descriptive results regarding the use of MRgLITT in a mixed population of pediatric, lesional, drug-resistant epilepsy cases. The ability to classify case-specific outcomes and reduce technical complications is anticipated as experience develops. Further multicenter, prospective studies are required to delineate optimal candidates for MRgLITT, and larger cohorts are needed to more accurately define outcome and complication rates.