Abstracts

Rationale: Treatment for pediatric patients with medically refractory epilepsy always needs multimodal strategies including ketogenic diet, focus resection or disconnection by cranial surgery, or vagus nerve stimulation (VNS). VNS has been well recognized as one of the treatment options for palliation. When VNS was approved by the FDA in 1997, VNS was indicated for adult and adolescent patients 12 years and older with medically refractory partial onset seizures. However, its use for young children is widely accepted at present. An investigation regarding its indications, effectiveness in seizure control, and safety of VNS in the pediatric population was carried out to establish therapeutic strategy for medically refractory epilepsy focused on VNS in children. Methods: Seventy consecutive pediatric patients (38 girls and 32 boys) 15 years and younger (mean age 9.3 years, range 3-15 years) underwent an implantation of the VNS Therapy System (Cyberonics, Inc., Houston, TX) for the treatment of medically refractory epilepsy and were followed up at the NYU Comprehensive Epilepsy Center. The exact indications for VNS, long-term outcome in terms of seizure reduction and complications by the treatment with VNS particularly in children were analyzed retrospectively. Results: Fifty-one patients were treated only with VNS, and 19 other patients were treated by combination with VNS and cranial surgery such as resection and/or disconnection. Most of the reasons why VNS was chosen for the treatment were that cranial surgery was not an appropriate option because patients had intractable generalized (40%) or multifocal epilepsy (40%), and failed cranial surgery (17%) followed as the next. The long-term follow-up data from 29 months up to 150 months (mean 83.3 months) demonstrated more than 80% seizure reduction in 19 patients (27%), more than 50% seizure reduction in 18 patients (26%), less than 50% seizure reduction in 20 patients (28%), and no response in 13 patients (19%). No statistical difference in the rate of good responders of more than 50% seizure reduction was seen between patients with generalized epilepsy and localization-related epilepsy. VNS also worked for patients treated by combination of VNS and cranial surgery including failed cranial surgery. One case of complication with postoperative wound infection (1.4%) was experienced and the system was explanted immediately. Conclusions: VNS should be considered as a treatment option when cranial surgery is not justified after sufficient discussion on the strategy for medically refractory epilepsy even in the pediatric population. VNS is especially offered to patients with generalized or multifocal epilepsy at the NYU Comprehensive Epilepsy Center. Failed cranial surgery is also one of the suitable indications. VNS works well for palliation in seizure control and is a safe treatment option for the pediatric population even if they experience common side effects secondary to electrical stimulation.