Abstracts

Rationale: To assess a long-term outcome in paediatric patients who received a vagus nerve stimulator (VNS) in pharmaco-resistant epilepsy. We examined seizure-frequency outcome, sustenance of response, effect on different seizure types, rate and causes of discontinuation, side effects encountered and effect on quality of life for the patients and their family. Methods: Retrospective case notes review and direct liaison with the families Results: Complete pre and post-VNS data were available for 30/31 patients. Median duration of epilepsy was 16 (7-26) years and median age at implantation was 11.5 (3-18) years. Both mean and median duration of follow-up was 8 (5-11) years. As compared to the baseline, seizure-frequency outcome was as follows. After 12 months, 40% achieved over 50% reduction in reported seizures and a further 37% achieved 10-50% reduction. At three year follow-up 43% achieved over 50% reduction and further 21% achieved 10-50% reduction. After five years, 45% achieved more than 50% reduction and a further 22% achieved 10-50% reduction. At 8 and 11-year follow-up 50% achieved more than 50% reduction and a further 33% reported 10-50% reduction. 3/30 patients showed over 90% reduction in seizure-frequency within the first year and the effect was sustained. No response (<10% reduction) on seizure frequency was observed in 9/27 (33%) patients at 5-year follow-up. The long-term discontinuation rate was just over 20% and mainly reflected a lack of clinical response. 14/18 families reported improved quality of life irrespective of seizure control Conclusions: In our series VNS was well tolerated with a low complication rate and proved to be an effective adjunct in pharmaco-resistant epilepsy. Effectiveness increases with time and in the majority the effect is sustained. The improvement in quality of life after VNS does not necessarily correlate with the improved seizure control alone