Effect of Transcutaneous Auricular Vagus Nerve Stimulation on Postoperative Ileus Following Minimally Invasive Colorectal Resection: A Single-Center Randomized Controlled Trial

Background Postoperative ileus (POI) is a common complication after colorectal surgery, leading to delayed recovery and prolonged hospitalization. Although vagus nerve stimulation has shown promise in enhancing gastrointestinal motility in preclinical and early clinical studies, evidence in the perioperative setting remains limited. This study evaluated whether perioperative transauricular vagus nerve stimulation (taVNS) could improve postoperative bowel recovery in patients undergoing minimally invasive colorectal resection. Methods In this randomized, sham-controlled trial, 79 patients scheduled for elective minimally invasive colorectal resection were assigned to receive either taVNS or sham stimulation. The primary outcome was time to first defecation (TFD). Secondary outcomes included time to first flatus (TFF), time to tolerance of semisolid food (TOF), postoperative pain scores, opioid consumption, postoperative complications, length of stay, 30-day readmission, and perioperative inflammatory markers. Analyses followed the intention-to-treat principle. Results Compared with the sham group, the taVNS group demonstrated significantly shorter TFD (71.5 [62.0–89.8] vs. 90.0 [63.5–114.5] hours; adjusted hazard ratio [HR] 2.04, 95% CI 1.22–3.40; p  = 0.01) and TOF (116.0 [108.0–135.0] vs. 133.5 [114.0–161.5] hours; adjusted HR 1.85, 95% CI 1.12–3.07; p  = 0.02). The taVNS group exhibited a smaller postoperative day-1 increase in white blood cell count (β = −0.14, 95% CI − 0.27 to − 0.01; p  = 0.04). Conclusions Perioperative taVNS accelerated gastrointestinal recovery and attenuated early postoperative inflammation following minimally invasive colorectal surgery. These findings support taVNS as a promising noninvasive strategy to reduce POI, meriting confirmation in larger multicenter studies. Trial registration ChiCTR2400083015, registered April 13, 2024.