Abstracts

Rationale: Vagal nevre stimulation (VNS) in the treatment of intractable epilepsy in childhood has been known as one of the most effective treatment methods with an average decrease in seizure frequency by 40%. The aim of this study is to investigate the seizure frequency before VNS surgery and effects of changes in duty cycle (on and off times) on the efficacy of VNS therapy in children with intractable epilepsy. Methods: We performed a retrospective study on 7 patients with intractable pediatric epilepsy who underwent VNS implantation surgery at the Dr.Beh et Uz Children's Research and Training Hospital during the time period from 2011 to 2013 and who had a minimum of 3 months of follow-up after VNS implantation. Outcome was quantified as percent seizure decrease from baseline. Statistical analysis of the data was done to determine if device settings and duty cycle changes significantly influenced the outcome. All parameters are evaluated primarily by descriptive analysis methods . As a measure of the distribution standard deviation (SD) and where appropriate, interquartile range (IQR) and minimum / maximum criteria is used. Wilcoxon test is used to compare the frequecy os seizures with baseline. All analyzes are performed using SPSS 15.0 software. P value of <0.05 was considered statistically significant. Results: The study group included 2 boys (% 28,6) and 5 girls (% 71,4); mean age was 15,14 years (SD 3,48). All patients involved in the study suffered frequent seizures despite multiple trials of antiepileptic medications, and one had tried Modified Atkins Diet. The etiologies of those patients were malformation of cortical development, destructive encephalopathy, ischemic encephalopaty, and unknown epilepsy. Postoperatively, 1 patient (14,2 %) was seizure free (Engel class I). 7 patients (85,8 %) got favorable results (Engel class II ). The device was well tolerated in all patients without significant complications. For off-time analysis, the principal designated by the programming software were used; 5min off, 3 min off,1,8 min off and 1,1 min off. Before VNS therapy seizure median rate 120 (IQR 120, min 8 max 300).After duty cycle changes seizure median rate 7 (IQR 4, min 0 max 40). Patients experienced a statistically signifant median decrease in seizures (p=0,018).Conclusions: Vagal nevre stimulation is considered a safe option in epilepsy management. This study demonstrates that significant rate of pediatric patients with intractable epilepsy can obtain seizure control by Vagal nevre stimulation therapy with changes in duty cycle.