Abstracts

Rationale: To review in a retrospective fashion the short term versus long term effectiveness of the Vagal Nerve Stimulator (VNS) in patients with intractable seizures. Methods: We reviewed a total of 14 patients who underwent VNS placement at our facility as an alternative treatment option for intractable seizures. We limited our analysis to patients followed in our outpatient clinic for a long term period. Results: Of the fourteen patients reviewed thirteen patients were adults ranging in age from 21 to 49 years. One was a pediatric patient of 10 years of age. Of the 14 patients analyzed 57% were diagnosed with symptomatic epilepsy and 43% had complex partial seizures. Mild to moderate adverse events including local tenderness and tightness, voice changes, and choking were noted in 71% of patients. Many of these were ameliorated by a change in VNS setting. Over one year 71% of patient showed significant improvement in the frequency of seizures, 14.5% of patient showed no improvement, and 14.5% showed worsening of seizure frequency. In comparison to the number of seizures prior to VNS placement and at 2 years, 79% showed significant improvement in frequency in seizures whereas 14% showed no improvement, and 7% showed worsening. Of the 2 patients showing no improvement one VNS was removed due to no effect since placement. Of the 13 patients who maintained their VNS for 5 years; 46% continued to show improvement when compared to the frequency of seizures prior to the VNS placement, 8% showed no change in frequency of seizures, 8% showed worsening of seizures, 15% removed the VNS due to no effect or worsening, and 23% are unknown as they did not follow up. Conclusions: The VNS is FDA approved as a neurocybernetic prosthetic for the adjunctive treatment of partial seizures that are refractory to antiepileptic drugs in patients over 12 years of age and have been tested in clinical trials for patients younger than 12 years of age and for other seizure types in specialized epilepsy centers. Our data showed substantial decrease in the frequency of seizures that was maintained throughout 1 and 2 year follow up intervals. At the 5 year interval there still is significant improvement in the control of seizures but is less than at the 2 year mark. Although a majority of patients had complications, they were mostly mild and did not prevent them from using the VNS.