Vagus nerve stimulation for epilepsy
Buckley E, Merlin T, Hiller JE
Record ID 32012000221
Original Title: Application 1118
Authors' results and conclusions: Safety - The assessment considered the comparative safety of vagus nerve stimulation (VNS) plus anti-epileptic drug (AED) therapy relative to AED therapy alone in adults, and AED therapy with or without the ketogenic diet in children. The population were strictly those patients with medically refractory epilepsy who had previously failed resective surgery or for whom such surgery was not considered an option. Complications associated with implantation included infection and vocal cord paralysis due to manipulation of the vagus nerve. In adults these occurred in up to 20% and 11%, respectively. In children, the incidence of infection occurred in up to 11% of patients. The most common outcome of infection in children was removal of the VNS device, with 55% of infections requiring device removal. Voice alteration and coughing were the most commonly reported adverse events associated with VNS stimulation. Voice alteration or hoarseness was reported by the majority of adults and children receiving VNS therapy, but more commonly in adults than children (12-100% and 8-53%, respectively). VNS therapy itself appears to be an acceptably safe procedure in terms of implantation surgery and delivery of stimulation. It is important to keep in mind that VNS therapy will be concomitant with AED therapy, which itself may be associated with adverse side effects. As such, any complications associated with VNS therapy will be in addition to AED therapy. It follows, therefore, that VNS plus AED therapy is no safer than AED therapy alone in patients (adults or children) with medically refractory epilepsy. Effectiveness - No evidence was identified to assess the comparative effectiveness of VNS plus AED therapy versus AED therapy alone in children. Based on level II and level III-2 intervention evidence, of fair to good quality although small sample size, it would appear that VNS plus AED therapy was more effective in reducing the average seizure frequency in adults than AED therapy alone (41-50% and 6-8% respectively. However, this statement comes with the stipulation that a clinically relevant reduction in seizure frequency would be seen in less than half (40%) of the adults who receive this therapy. Low-level evidence suggests that VNS plus AED therapy has a clinically significant effect in reducing seizure frequency in children with Lennox-Gastaut syndrome. In both adults and children, no comparative evidence was available to determine whether VNS plus AED therapy reduced the epilepsy-related mortality of patients, nor was there strong evidence of an improvement in quality of life. Economics - A lack of data and uncertainty regarding net benefit resulted in no formal economic evaluation being conducted; instead, a financial analysis of the expenditures associated with the therapies was performed. The expected uptake of this procedure (estimated at 30 procedures annually) is relatively small and therefore is not expected to result in a significant financial burden to the Australian Government. The financial implications of all healthcare costs associated with the implementation of VNS therapy for 30 patients is in the order of $650,000 in addition to the costs of AED therapy and excluding likely significant downstream costs. The potential for leakage in the public sector would be expected to increase the utilisation to 75 patients annually and the subsequent healthcare costs to $1,630,000 per year.
Project Status: Completed
Year Published: 2008
URL for published report: http://www.msac.gov.au/internet/msac/publishing.nsf/Content/5883241724B4D7E2CA25801000123B4D/$File/1118-Assessment-Report.pdf
English language abstract: An English language summary is available
Publication Type: Not Assigned
Organisation Name: Adelaide Health Technology Assessment
Contact Address: School of Public Health, Mail Drop 545, University of Adelaide, Adelaide SA 5005, AUSTRALIA, Tel: +61 8 8313 4617
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Copyright: Adelaide Health Technology Assessment (AHTA)
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