Impact of transcutaneous auricular vagus nerve stimulation on postoperative pain in patients undergoing perianal surgery: a randomized trial

This study aims to evaluate the effectiveness of transcutaneous auricular vagus nerve stimulation (taVNS) on postoperative pain in patients following perianal surgery. 96 patients were randomly assigned to either the taVNS group or the sham stimulation group. Patients received stimulation once 30 min before the operation and once more 24 h after the operation, with each session lasting 30 min. The VAS scores were recorded at 2, 6, 24, 48, and 72 h, as well as 7 days postoperatively. Data were collected on the first change of dressing, the first defecation, the frequency of supplementary analgesia, and the occurrence of adverse reactions. Patient satisfaction was assessed at the time of hospital discharge. The VAS scores of patients in the taVNS group were significantly lower than those in the sham stimulation group at 2, 6, 24, 48, and 72 h postoperatively, at the time of the first dressing change, and at the time of the first defecation (<i>p</i> &lt; 0.05). The rate of postoperative supplementary analgesic use was significantly higher in the sham stimulation group compared to the taVNS group (<i>p</i> &lt; 0.05). The incidence of urinary retention was lower in the taVNS group (<i>p</i> &lt; 0.05). No adverse reactions like hypotension or bradycardia were observed in either group. Patient satisfaction was higher in the taVNS group (<i>p</i> &lt; 0.05). taVNS effectively alleviates postoperative pain in patients undergoing perianal surgery without increasing the risk of complications.