Vagus Nerve Stimulation Therapy and Epilepsy Surgery

In this chapter we discuss the role of vagus nerve stimulation and epilepsy surgery. The history, efficacy, and outcomes of vagus nerve stimulation (VNS) are described, with reference to trials and studies in both humans and animals. Latest thinking on the therapeutic mechanism of VNS is outlined, and the salient aspects of patient selection, implantation of the device, and maintenance are presented, along with the advantages and drawbacks of this therapy. For children with medically intractable epilepsy, neurosurgical intervention may allow seizure control and in some cases even a cure. The phases of evaluating a child for epilepsy surgery are detailed: in phase I, patients are evaluated through non-invasive techniques to establish whether a patient is a candidate for epilepsy surgery. Phase II, which may not be necessary in some instances, involves invasive electrode monitoring for more precise localization of the epileptogenic zone in relation to functional cortex. Phase III involves the actual epilepsy surgery. The current modalities for evaluating not only the source of epileptogenesis but also the functional cortex, are outlined.