Vagus nerve stimulator en epilepsia fármaco-resistente

Resumen

Background: Epilepsy is a common neurological disease that affects 1% of the population. One third of patients with epilepsy will not respond to antiseizure medications. The most effective treatment when a patient has medically resistant epilepsy is epilepsy surgery. Unfortunately, in many cases surgery is not possible. Neuromodulation is a therapy used in those patients and Vagus Nerve Stimulation (VNS) is the most common type. There are many studies focusing on seizure reduction using VNS, it is still unclear which patients will obtain the greatest benefits. Objective: To define the seizure response post-VNS implantation, to determine predictive factors associated with good outcomes after VNS implantation and to evaluate complications and side effects. Analysis will be completed in the total sample of VNS cases, in the paediatric subgroup, in medically resistant generalized epilepsy and pregnant women implanted with VNS. Patients & Methods: Patients with medically resistant epilepsy implanted with VNS at the London Health Science Centre-Western University, from 1997 to July 2018. Results: 1) VNS in epilepsy: 114 patients were included. Median seizure rate reduction was - 67.8% and 55.6% (n=41) had a ≥50% seizure reduction. There was a reduction of hospitalization after VNS implantation from 89.5% (n=102) to 45.6% (n=52). 5.3% (n=6) developed side effects associated with the implantation; and side effects were reported in 63.2% (n=72). 2) Paediatric Group: 22 patients were included. The median age when the VNS was implanted was 13. A ≥50% seizure reduction was achieved in 50% (n=11) and the median seizure reduction was -75%. Side effects were detected in 54.5% (n=12). 3) 46 patients were included in this study with a history of medically resistant generalized epilepsy. The mean age at implantation was 24 years-old. Of the LGS group 41.7% (n=12) of patients had an overall seizure reduction of ≥50%, and in the GGE group 64.7% (n=11) had a seizure reduction of ≥50%. There was a significant reduction of seizure-related hospital admissions. 4) Four patients and seven pregnancies were included. The median duration since implantation was 3.17 years. Three required c-sections, one related to failure to progress, the second due to pre-eclampsia and the third due to breach presentation. All babies were healthy, except one with developmental delay of unclear severity. Conclusion: 1) VNS can reduce the number of seizures by 50% in more than half of the patients implanted. VNS has shown a reduction in hospitalization. It is a safe therapy with frequent mild side effects. 2) The paediatric population obtained similar results compared to the total sample. 3) VNS should be considered as a treatment in patients with therapy resistant generalized epilepsy, especially in cases with GGE. 4) Our small sample suggests VNS is a relatively safe therapy during pregnancy, however, larger sample series should be collected.