Neuromodulation for Gastroesophageal Reflux Disease: A Systematic Review.

Background and objectives: In this systematic review, we evaluated the efficacy, mechanisms and safety of three neuromodulation therapies in patients with gastroesophageal reflux disease (GERD), including the effect of neuromodulation therapies on symptoms and key GERD pathophysiologies, lower esophageal sphincter (LES) pressure, esophageal motility, gastric motility, and parasympathetic activity. The first therapy is LES electrical stimulation using an implantable electrical stimulator, the second is transcutaneous electrical acustimulation, and the third is manual acupuncture. Methods: A systematic review of literature according to the PRISMA guidelines was performed. Online databases searched include Medline (Ovid), Embase, and PubMed. Studies were assessed for inclusion and exclusion criteria with Covidence, a systematic review software. Results: The analysis included thirteen clinical studies. Four papers included were registered under two open-label trials on ClinicalTrials.gov for LES electrical stimulation; Five randomized trials with sham-treated controls were analyzed for transcutaneous electrical acustimulation; Four studies, including three involving standard therapy controls and one involving shamtreated controls were included for manual acupuncture. All evaluated studies demonstrated significant beneficial effects on GERD symptoms, using patient-completed questionnaires, objective 24-h measurement of esophageal pH, and patient-reported use of proton pump inhibitors. In evaluating the effect on key GERD pathophysiologies, electrical stimulation significantly increased LES pressure, and transcutaneous electrical acustimulation significantly improved esophageal motility, gastric motility, and parasympathetic activity. None of the evaluated neuromodulation methods produced severe adverse effects. Conclusions: Cumulative evidence from the evaluated studies indicates that neuromodulation therapies were effective in treating the GERD symptoms and key underlying GERD pathophysiologies. They are thus valuable options for individualized GERD treatment.