OBJECTIVE

The objective of this study was to better understand the safety and efficacy of laser interstitial thermal therapy (LITT) for children with medically refractory epilepsy.

METHODS

Thirty-seven consecutive pediatric epilepsy patients at a single pediatric center who underwent LITT ablation of epileptogenic foci between May 2017 and December 2021 were retrospectively reviewed. Patient demographics, medication use, seizure frequency, prior surgical interventions, procedural details, and pre- and postoperative seizure history were analyzed.

RESULTS

Thirty-seven pediatric patients (24 male, 13 female) with severe medically refractory epilepsy were included; all underwent stereo-electroencephalography (SEEG) prior to LITT. The SEEG electrode placement was based on the preoperative workup and tailored to each patient by the epileptologist and neurosurgeons working together to identify the epileptic network and hopefully quiet borders. Seizure onset was at a mean age of 2.70 ± 2.82 years (range 0.25-12 years), and the mean age at the time of LITT was 9.46 ± 5.08 years (range 2.41-17.86 years). Epilepsy was lesional in 23 patients (18 tuberous sclerosis, 4 focal cortical dysplasia, 1 gliosis) and nonlesional in 14. Eighteen patients had prior surgical interventions including open resections (n = 13: 11 single and 2 multiple), LITT (n = 4), or both (n = 1). LITT targeted a region adjacent to the previous target in 5 cases. The median number of lasers placed during the procedure was 3 (range 1-5). Complications occurred in 14 (37.8%) cases, only 3 (8.11%) of which resulted in a permanent deficit: 1 venous hemorrhage requiring evacuation following laser ablation, 1 aseptic meningitis, 2 immediate postoperative seizures, and 10 neurological deficits (7 transient and 3 permanent). Postoperatively, 22 (59.5%) patients were seizure free at the last follow-up (median follow-up 18.35 months, range 7.40-48.76 months), and the median modified Engel class was I (Engel class I in 22 patients, Engel class II in 2, Engel class III in 2, and Engel class IV in 11). Patients having tried a greater number of antiseizure medications before LITT were less likely to achieve seizure improvement (p = 0.046) or freedom (p = 0.017). Seizure improvement following LITT was associated with a shorter duration of epilepsy prior to LITT (p = 0.044), although postoperative seizure freedom was not associated with a shorter epilepsy duration (p = 0.667). Caregivers reported postoperative neurocognitive improvement in 17 (45.9%) patients.

CONCLUSIONS

In this large single-institution cohort of pediatric patients with medically refractory seizures due to various etiologies, LITT was a relatively safe and effective surgical approach for seizure reduction and seizure freedom at 1 year of follow-up.