Vagus nerve stimulation vs. corpus callosotomy in the treatment of Lennox-Gastaut syndrome: A meta-analysis

Purpose: Lennox-Gastaut syndrome (LGS) is an epileptogenic disorder that arises in childhood and is typically characterized by multiple seizure types, slow spike-and-wave complexes on EEG and cognitive impairment. If medical treatment fails, patients can proceed to one of two palliative surgeries, vague nerve stimulation (VNS) or corpus callosotomy (CC). Their relative seizure control rates in LGS have not been well studied. The purpose of this paper is to compare seizure reduction rates between VNS and CC in LGS using meta-analyses of published data. Methods: A systematic search of Pubmed, Ovidsp, and Cochrane was performed to find articles that met the following criteria: (1) prospective or retrospective study, (2) at least one patient diagnosed with Lennox-Gastaut syndrome, and (3) well-defined measure of seizure frequency reduction. Seizure reduction rates were divided into seizure subtypes, as well as total seizures, and categorized as 100%, >75%, and >50%. Patient groups were compared using chi-square tests for categorical variables and t-test for continuous measures. Pooled proportions with 95% confidence interval (95% CI) of seizure outcomes were estimated for total seizures and seizure subtypes using random effects methods. Results: 17 VNS and 9 CC studies met the criteria for inclusion. CC had a significantly better outcome than VNS for >50% atonic seizure reduction (80.0% [67.0-90.0%] vs. 54.1% [32.1-75.4%], p < 0.05) and for >75% atonic seizure reduction (70.0% [48.05-87.0%] vs. 26.3% [5.8-54.7%], p < 0.05). All other seizure types, as well as total number of seizures, showed no statistically significant difference between VNS and CC. Conclusions: CC may be more beneficial for LGS patients whose predominant disabling seizure type is atonic. For all other seizure types, VNS offers comparable rates to CC. (C) 2012 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.