Lennox-Gastaut syndrome (LGS) is a drug-resistant pediatric epilepsy characterized by multiple seizure types, including drop attacks (DAs). Palliative procedures such as corpus callosotomy (CC) and vagus nerve stimulation (VNS) may be effective for adequate seizure control in LGS patients who are not candidates for resective surgery. We evaluated the efficacy of the combination of these two procedures for LGS-related seizures.
Ten patients with LGS (age 3-30 years at VNS implantation) underwent CC and subsequent VNS. We evaluated surgical outcomes, particularly with respect to the efficacy of VNS on seizure reduction rates for different residual seizure types after CC. We compared clinical parameters, including sex, age, seizure duration, history, MRI findings, extent of CC, number of antiepileptic drugs, and neuropsychological states, between VNS responders and non-responders to predict satisfactory seizure outcomes with respect to residual seizures after CC.
VNS was effective for residual seizures regardless of seizure type (except for DAs) after CC in patients with LGS. Six of ten (60%) patients had a satisfactory seizure outcome (a parts per thousand yen50% seizure reduction) for all residual seizure types after VNS. Two of ten (20%) patients were seizure-free at 12 months post-VNS. Even those patients that were non-responders, with respect to all seizures including DAs, after prior CC showed favorable responses to subsequent VNS. Compared to VNS, excellent seizure outcomes for DAs were achieved after CC in seven of nine (77.8%) patients with DAs. Among the clinical parameters, only conversation ability before VNS was significantly different between responders and non-responders (p = 0.033).
Combined VNS and prior CC produced satisfactory seizure outcomes in LGS patients with different seizure types, including DAs. Even non-responders to prior CC responded to subsequent VNS for residual seizures, except for DAs. There is a greater likelihood that these procedures may be more feasible in patients who possess conversation ability prior to VNS.