Low-intensity transcutaneous auricular vagus nerve stimulation reduces postoperative ileus after laparoscopic radical resection of colorectal cancer: a randomized controlled trial

BACKGROUND: Postoperative ileus (POI) is thought to result from a disrupted sympathetic/parasympathetic balance caused by trauma or surgery. Transcutaneous auricular vagus nerve stimulation (tVNS) is a non-invasive technique involving stimulation of the vagal auricular branch, leading to autonomic regulation and reduced inflammation. Here, the effects of low-intensity transcutaneous auricular vagal stimulation on POI after laparoscopic radical resection of colorectal cancer were investigated. METHODS: One hundred and thirty-four patients who received scheduled laparoscopic radical resection of colorectal cancer were randomly allocated to the A and B groups. The A group received low-intensity (25 Hz, 50 mA) transcutaneous electrical stimulation of the right auricular branch for 20 minutes prior to anesthesia while the B group did not. The primary outcome was the incidence of POI. RESULTS: The incidence of POI in the A group was 6.25% and 20% in the B group (P=0.022). Patients in the A group showed more regular bowel sounds after 24, 36, and 48 h than those in the B group (P<0.001). CONCLUSIONS: Low-intensity transcutaneous auricular vagal stimulation reduced POI after laparoscopic radical resection of colorectal cancer.