Vagus nerve stimulation for intractable epilepsy: outcome in two series combining 90 patients.
ABSTRACT Vagus nerve stimulation (VNS) is the most widely used non-pharmacological treatment for medically intractable epilepsy and has been in clinical use for over a decade. It is indicated in patients who are refractory to medical treatment or who experience intolerable side effects, and who are not candidates for resective surgery. VNS used in the acute setting can both abort seizures and have an acute prophylactic effect. This effect increases over time in chronic treatment to a maximum at around 18 months. The evidence base supporting the efficacy of VNS is strong, but its exact mechanism of action remains unknown. A vagus nerve stimulator consists of two electrodes embedded in a silastic helix that is wrapped around the cervical vagus nerve. The stimulator is always implanted on the left vagus nerve in order to reduce the likelihood of adverse cardiac effects. The electrodes are connected to an implantable pulse generator (IPG) which is positioned subcutaneously either below the clavicle or in the axilla. The IPG is programmed by computer via a wand placed on the skin over it. In addition, extra pulses of stimulation triggered by a hand-held magnet may help to prevent or abort seizures. VNS is essentially a palliative treatment and the number of patients who become seizure free is very small. A significant reduction in the frequency and severity of seizures can be expected in about one third of patients and efficacy tends to improve with time. Vagus nerve stimulation is well tolerated and has few significant side effects. We describe our experience on the use of VNS on drug-resistant epilepsy in 90 patients treated in two departments (in Athens, Greece and Newcastle, England).
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ABSTRACT: Neuromodulation strategies have been proposed to treat a variety of neurological disorders, including medication-resistant epilepsy. Electrical stimulation of both central and peripheral nervous systems has emerged as a possible alternative for patients who are not deemed to be good candidates for resective procedures. In addition to well-established treatments such as vagus nerve stimulation, epilepsy centers around the world are investigating the safety and efficacy of neurostimulation at different brain targets, including the hippocampus, thalamus, and subthalamic nucleus. Also promising are the preliminary results of responsive neuromodulation studies, which involve the delivery of stimulation to the brain in response to detected epileptiform or preepileptiform activity. In addition to electrical stimulation, novel therapeutic methods that may open new horizons in the management of epilepsy include transcranial magnetic stimulation, focal drug delivery, cellular transplantation, and gene therapy. We review the current strategies and future applications of neuromodulation in epilepsy.Neurosurgery. 10/2011; 69(4-Oct;69(4):957-79):957-79.
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ABSTRACT: OBJECTIVES: The aim of the study was to evaluate the long-term efficacy and hospitalization rates in children with refractory focal epilepsy treated by vagus nerve stimulation. MATERIALS AND METHODS: We retrospectively analyzed 15 children with intractable focal epilepsy treated by vagus nerve stimulation (mean age of 14.6 ± 2.5 years at the time of implantation). We analyzed the treatment effectiveness at 1, 2, and 5 year follow-up visits. We counted the average number of urgent hospitalizations and number of days of urgent hospitalization per year for each patient before and after the VNS implantation. RESULTS: The mean seizure reduction was 42.5% at 1 year, 54.9% at 2 years, and 58.3% at 5 years. The number of responders was 7 (46.7%) at 1 year and 9 (60%) at both 2 and 5 years. The mean number of urgent hospitalizations per patient was 1.0 ± 0.6 per year preoperatively and 0.3 ± 0.5 per year post-operatively (P < 0.0001). The mean number of days of urgent hospitalization per patient was 9.3 ± 6.1 per year preoperatively and 1.3 ± 1.8 per year post-operatively (P < 0.0001). CONCLUSIONS: Vagus nerve stimulation is an effective method of treating children with refractory focal epilepsy. It leads to a substantial decrease in the number and duration of urgent hospitalizations.Acta Neurologica Scandinavica 09/2012; · 2.47 Impact Factor
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ABSTRACT: Vagus nerve stimulation (VNS) is one of the numerous stimulation procedures used in the treatment of neurological diseases in which there has been growing interest in recent years. Since 1988 it has been frequently used in the therapy of epilepsies but the mechanism of action is still unknown. It is considered to be low in adverse effects. Decision-making process on VNS therapy as well as long-term outcome and adverse effects. Retrospective analysis of all 62 patients treated over a long period by VNS in the Epilepsy Center of the University Hospital of Freiburg (Germany) from 1 August 2002 through 4 January 2011. Outcome: the results show that 2 out of 62 patients became seizure-free under VNS therapy while maintaining the already existing anti-ictal medication and 4 more patients under VNS plus dosage increase of the already existing medication and/or new medication. However, in 34 out of 62 patients VNS therapy did not improve the seizure situation. Adverse effects: VNS is not as low in adverse effects as is generally considered. Only 9 out of 62 patients did not show any adverse effects and on the other hand severe, even life-threatening adverse effects also occurred. Patients undergoing VNS therapy have to be carefully checked for possible adverse effects, not only at the beginning of VNS therapy but also in the long-term course. These results have to be considered in the cost-benefit analysis of this treatment.Der Nervenarzt 11/2013; · 0.80 Impact Factor