Review of the Uses of Vagal Nerve Stimulation in Chronic Pain Management

Recent human and animal studies provide growing evidence that vagal nerve stimulation (VNS) can deliver strong analgesic effects in addition to providing therapeutic efficacy in the treatment of refractory epilepsy and depression. Analgesia is potentially mediated by vagal afferents that inhibit spinal nociceptive reflexes and transmission and have strong anti-inflammatory properties. The purpose of this review is to provide pain practitioners with an overview of VNS technology and limitations. It specifically focuses on clinical indications of VNS for various chronic pain syndromes, including fibromyalgia, pelvic pain, and headaches. We also present potential mechanisms for VNS modulation of chronic pain by reviewing both animal and human studies.