Abstracts

Intermittent stimulation of the left vagus nerve is an approved adjunctive therapy for medically intractable partial onset epilepsy in children 12 years and older. Management of children less than 12 years of age with intractable epilepsy, particularly those with epileptic encephalopathies remains challenging despite the availability of new drugs. This study reports outcomes on 100 patients, aged 2-22 at implantation, including 56 [apos][lt]12[apos] between 1/98 and 4/06., Data were gathered using retrospective chart review. Variables included seizure frequency at the surgical visit, seizure frequency at 12 month follow-up, seizure frequency at 24 month follow-up, and seizure frequency at last visit. Frequencies were recorded as number per week, and were extrapolated from records in the patient[apos]s chart. We documented prior number of medications and post number of medications. Post operative complications were noted., The average age at implantation was 10.6 years (SD= 4.9). The average reduction of seizures was 45% (SD= 40); percent reduction was defined as 100*(1- number of post seizures/ number of prior seizures). 14 patients were lost to follow-up. 33 patients had incomplete data and were excluded from this calculation. 15 patients had [gt]89% seizure reduction; 3 became seizure-free with VNS, 1 post resection. We also devised a qualitative improvement rating scale: significant improvement (70% reduction or greater), moderate improvement (1-69% reduction), no improvement (0%). 26/ 77 had significant, 18/ 77 had moderate, and 33/ 77 had no improvement (9 had incomplete data). An analysis of medication reduction showed no decrease. We saw no difference between the [lt]12 age group and the [gt]12 group. Percent reduction showed no difference (42%,SD=41: 46%, SD=39). In the [lt]12, 13/41 had significant, 10/41 had moderate, 18/41 had no improvement. In the [gt]12, 13/36 had significant, 8/36 had moderate, 15/36 had no improvement. 5 [apos][gt]12[apos] and 9 [apos][lt]12[apos] were lost to follow-up. 28 [apos][lt]12[apos] were treated with the ketogenic diet, compared to 14 [apos][gt]12[apos]. 6 patients had their VNS removed (3 due to infection), 6 stimulators were replaced. 5 patients had post-implant callosotomies (all [lt]12 group). 2 patients died, one from failure to thrive, one from status epilepticus., VNS has efficacy in children under age 12 years with generalized epilepsies. Although clearly not a cure or a sole therapy for most patients, our data support the position that VNS is a safe and effective adjunctive therapy for pharmacoresistant epilepsy in children [lt]12 years of age. We observed no difference in the efficacy and outcomes of children [lt]12 treated with VNS when compared to the [gt]12 group.,