S402 Therapeutic Role of Vagus Nerve Stimulation in the Management of Gastrointestinal Disorders: A Systematic Review

Introduction: The vagus nerve regulates how the stomach, intestines, and colon work, influences the secretion of fluids, and how their muscles contract and cause inflammation. Stimulating the vagus nerve through treatment methods—surgery or cutaneous devices—is now being tested for gastrointestinal (GI) conditions. Clinical studies before human use reveal that vagus nerve stimulation (VNS) may decrease inflammation and pain in the GI tract by activating so-called cholinergic pathways and neuromodulation. Methods: We systematically looked at studies on VNS, whether invasive or non-invasive use in gastrointestinal disorders. Through 2025, trials were searched on PubMed, Embase, Web of Science, and the Cochrane Library for randomized controlled trials (RCTs) of VNS versus sham in people with inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), functional dyspepsia, and gastroparesis. Quality of life, adverse effects, and symptom scores were the information reviewed. The quality of the methods used was assessed with the Cochrane RoB2 tool. With limited RCTs, a qualitative synthesis was carried out. Results: Seven RCTs involving 644 patients used non-invasive (transcutaneous) VNS to treat functional dyspepsia (426), IBS (92), IBD (22), and functional abdominal pain (104) over 2–12 weeks. VNS significantly improved GI symptoms compared to sham across all conditions. In functional dyspepsia, 66% of VNS patients responded vs 31% with sham. IBS patients reported less abdominal pain and more regular bowel movements. No serious adverse events occurred; mild side effects like tingling and headache were rare. VNS may reduce inflammation and pain by enhancing vagal tone and lowering pro-inflammatory cytokines. While bias was minimal, study sizes were small. Conclusion: VNS shows promise as a safe adjunct for various GI disorders. Non-invasive VNS was particularly effective for functional GI conditions and showed some benefit in IBD by modulating gut-brain interactions. These findings highlight its therapeutic potential, but larger studies with longer follow-up are needed to confirm efficacy and guide optimal use. VNS could complement existing treatments for challenging GI cases.