Purpose: The vagal nerve stimulator (VNS) and corpus callosotomy can reduce seizure frequency when seizures are refractory to medications. However, the efficacy and safety of these two procedures have not been compared. This study evaluates the two procedures for generalized seizures.
Methods: All patients with refractory generalized seizures (generalized tonic-clonic, tonic, or atonic) who underwent a corpus callosotomy (anterior or complete) (n = 53) without other forms of epilepsy surgery and those who underwent VNS placement (n = 25) were evaluated for this study. Seizure response and procedure complications were evaluated.
Results: For those with a corpus callosotomy and generalized tonic-clonic seizures (n = 50), 79.5% had >or=50% decrease in the frequency of generalized tonic-clonic seizures, and 60% had >or=80% seizure reduction. For those with a VNS and generalized tonic-clonic seizures (n = 21), 50% had >or=50% seizure reduction, and 33% had >or=80% seizure reduction. Tonic and atonic seizures decreased after either VNS or a corpus callosotomy. The complication rate for corpus callosotomy was higher (21% all complications, 3.8% permanent) than that for VNS (8%; none permanent), but complications for both corpus callosotomy and VNS were rarely permanent.
Conclusions: Both corpus callosotomy and VNS are effective in reducing generalized seizures. Corpus callosotomy is associated with greater efficacy but higher risk for complications, although these were generally transient.