Combined ketogenic diet and vagus nerve stimulation: Rational polytherapy?

Objective: The concept of "rational polypharmacy" has been associated with anticonvulsant management for decades, but the term has not been applied to nonpharmacologic therapies. Methods: We conducted a multicenter, retrospective study of children who received concurrent diet (ketogenic or modified Atkins) and vagus nerve stimulation (VNS) treatment for medically intractable epilepsy. Results: Thirty children in total from six epilepsy centers were treated over a 6-yr period. The median age at the initiation of combination therapy was 10 yr (range, 4-24 yr). Sixteen (53%) received dietary therapy followed by VNS; no differences were noted between centers. After 3 months, 21 (70%) had seizure reduced by >50% over the previous single nonpharmacologic treatment, of whom 13 (62%) had improvement within the first month. A 5-min VNS off-time correlated with >90% seizure reduction (p = 0.02). The median duration of nonpharmacologic polytherapy was 12 months (range, 0.5-96 months); 17 (57%) remain on dual therapy at this time. No side effects were noted. Most patients who discontinued combination therapy did so because of a lack of efficacy rather than restrictiveness. Conclusions: In this small group, the combined use of diet and VNS appeared synergistic and yielded rapid benefits. It may be more effective with longer VNS off-times. Further prospective studies of this combination in refractory pediatric epilepsy are needed to help guide optimal use.