Transcutaneous Vagal Nerve Stimulation for Gastrointestinal Disorders.

Imbalanced autonomic function has been reported in gastrointestinal (GI) disorders. The vagus nerve is a major component in the regulation of upper GI motility. Vagal nerve stimulation (VNS) has been shown to improve symptoms of various GI disorders by enhancing parasympathetic activity. This review aims to summarize the clinical efficacy of transcutaneous VNS for GI disorders, focusing on abdominal pain, other GI symptoms, and GI motility, and to discuss the mechanisms of action of transcutaneous VNS. Randomized clinical trials investigating transcutaneous VNS in several major GI disorders, including functional dyspepsia, gastroparesis, constipation, irritable bowel syndrome, and inflammatory bowel disease, were reviewed and discussed. The forms of transcutaneous VNS covered in this review include transcutaneous auricular VNS, transcutaneous cervical VNS, and percutaneous electrical nerve field stimulation. Transcutaneous VNS has been shown to relieve abdominal pain, improve GI symptoms, and accelerate GI motility by enhancing vagal activity in patients with various GI disorders. Transcutaneous VNS is an innovative, effective, and safe therapy for patients with GI disorders; however, large-scale clinical trials are necessary to establish optimal treatment modalities and efficacy.