Authors: Sara Hartnett, MD
Pediatric epilepsy is diagnosed as drug-resistant in 20-30% of cases, defined as persistent seizures despite treatment with two first-line antiepileptic medications. The American Academy of Neurology advocates surgical options early in treatment to provide long-term seizure reduction. The development of minimally invasive approaches allows surgical options for patients previously not deemed surgical candidates, such as those with bilateral, deep, or eloquent. Responsive neurostimulation (RNS) is an FDA approved closed loop neuromodulation device for adjuvant treatment of adults with medically intractable epilepsy arising from one or multiple foci.Methods: In this study, the authors describe their institutions experience with the use of RNS in pediatric patients with drug-resistant epilepsy. An IRB approved retrospective review of nine pediatric patients who underwent RNS implantation at Cincinnati Childrens Hospital between 2019 and 2021 was conducted.
The average age at the time of surgery was 14.7 years (range: 8 to 17 years) with a mean follow up of 9.8 months. Fifty five percent of patients had prior surgical intervention for epilepsy. Five patients had bilateral seizure onset zones, while 3 patients had targets in eloquent cortex. Trajectories were based upon invasive and non-invasive seizure onset zone localization data. The authors demonstrated six individualized electrode trajectory and placements including amygdala/hippocampus, bilateral insular targets, bilateral parietal and occipital targets with a total number of 16 electrodes implanted. All electrodes were placed with robotic-assisted guidance and confirmed to be accurate compared to the pre-operative plan. One adverse event occurred, a wound infection requiring return to the operating room.
All patients demonstrated reduction in seizure frequency. Two patients with greater than one year follow up had ILAE outcome scores of 4 and 5 respectively. RNS implantation in carefully selected pediatric patients appears safe and efficacious in reducing seizure burden in this patient population with low complication risks.