Evidence-based guideline update: Vagus nerve stimulation for the treatment of epilepsy

Abstract

Objective: To evaluate the evidence since the 1999 assessment regarding efficacy and safety of vagus nerve stimulation (VNS) for epilepsy, currently approved as adjunctive therapy for partial-onset seizures in patients .12 years. Methods:We reviewed the literature and identified relevant published studies. We classified these studies according to the American Academy of Neurology evidence-based methodology.Results: VNS is associated with a .50% seizure reduction in 55% (95% confidence interval [CI] 50%-59%) of 470 children with partial or generalized epilepsy (13 Class III studies). VNS is associated with a .50% seizure reduction in 55% (95% CI 46%-64%) of 113 patients with Lennox-Gastaut syndrome (LGS) (4 Class III studies). VNS is associated with an increase in $50% seizure frequency reduction rates of ;7% from 1 to 5 years postimplantation (2 Class III studies). VNS is associated with a significant improvement in standard mood scales in 31 adults with epilepsy (2 Class III studies). Infection risk at the VNS implantation site in children is increased relative to that in adults (odds ratio 3.4, 95% CI 1.0-11.2). VNS is possibly effective for seizures (both partial and generalized) in children, for LGS-associated seizures, and for mood problems in adults with epilepsy. VNS may have improved efficacy over time.Recommendations: VNS may be considered for seizures in children, for LGS-associated seizures, and for improving mood in adults with epilepsy (Level C). VNS may be considered to have improved efficacy over time (Level C). Children should be carefully monitored for site infection after VNS implantation. Neurology In 1997, the US Food and Drug Administration (FDA) approved vagus nerve stimulation (VNS) as adjunctive therapy for reducing the frequency of seizures in patients .12 years of age with partialonset seizures refractory to antiepileptic medications.1 A 1999 American Academy of Neurology (AAN) technology assessment concluded that VNS is indicated for patients .12 years with medically intractable partial seizures who are not candidates for potentially curative surgical resections such as lesionectomies or mesial temporal lobectomies. The authors also recommended that patients undergo a thorough epilepsy evaluation to rule out nonepileptic conditions or treatable symptomatic epilepsies before implantation of a vagus nerve stimulator. At that time, evidence was insufficient to recommend VNS for epilepsy in young children or for seizures associated with Lennox-Gastaut syndrome (LGS). Since the 1999 AAN assessment, the FDA has approved VNS for the adjunctive long-term treatment of chronic or recurrent depression in patients .18 years who are experiencing a major depressive episode and have not had an adequate response to 4 or more adequate antidepressant treatments.1 Moreover, there are new reports of long-term efficacy and VNS use in pediatric epilepsy and other seizure types and syndromes. We evaluated this evidence using the AAN guideline methodology.

Complications and safety of vagus nerve stimulation: 25 years of experience at a single center

“…The major safety questions from the evidence-based analysis that still need to be clarified are if new safety concerns have emerged over time for sudden unexpected death in epilepsy (SUDEP), cardiac arrhythmias during and after implantation, and sleep apnea. 26 A recent review presents safety data from clinical trials and databases, 9 and results concerning SUDEP and patients with VNS from a single center were also reported recently. 16 The long-term follow-up is limited in most studies; however, Kahlow and Olivecrona 21 presented data over a 17-year period between 1994 and 2010.…”

The role of vagus nerve stimulation in refractory epilepsy

“…Irreversible nerve damage, in turn, is usually rare 44 . Whereas studies report rates of 1% to 5% of hardware malfunction 4 , these estimates are highly variable. Révész et al 40 published a 3% incidence of lead breakage, noticed mainly by the increase of seizure frequency, as not all fractures are identified on imaging screening.…”

“…Although its mechanism of action has not been completely elucidated, it possibly involves diffuse cerebral metabolic changes, cortical and subcortical, through modulation of solitary tract nucleus and brainstem activities 3 . Its efficacy is related to reduction of both frequency and duration of seizures as well as improvement in quality of life 4 . This review aims to assess the main concepts involved in vagus nerve stimulation, from its anatomical principles and mechanisms of action to the recommendations regarding its indications, usual parameters and new trends.…”

“…However, decreasing the ' off time' to 1.1 min or less in one group provided seizure reduction of 39%, as opposed to 21% in the group with baseline settings stimulation 27 . Although some researches advise fast stimulation (7 sec on and 30 sec off), no statistical superiority has been demonstrated yet 4 . Furthermore, increments in stimulation parameters will drain battery life and raise the need for generator replacement.…”

Calculation of the Need of Multidisciplinary Units of Epilepsy in America

“…The success of the surgery depends among others factors, of the years that carry the patient with the crises, the type of underlying injury, and the affected lobe. The total control of the post-surgery crises ranging from 50-80% [8][9][10][11].…”