Effect of transcutaneous electrical nerve stimulation based on wrist-ankle acupuncture theory for pain relief during colonoscopy without anesthesia: a randomized controlled trial

BACKGROUND: Colonoscopy is essential for diagnosing colorectal diseases but can cause pain during the procedure. This study explored the analgesic effects of transcutaneous electrical nerve stimulation based on wrist-ankle acupuncture theory (TENS-WAA) in colonoscopy without anesthesia. METHODS: This prospective study included 120 participants undergoing colonoscopies without anesthesia. The trial group received low-frequency, high-intensity TENS-WAA adjusted to the maximum tolerable current, while the control group received minimal current. The primary outcome was the retrospective pain score on a visual analog scale (VAS). Secondary outcomes included time, heart rate, and credibility/expectancy questionnaire (CEQ) scores. RESULTS: Participants who received TENS-WAA reported significantly lower pain VAS scores than the control group (estimated median difference -1.1, 95%CI -2 to -0.4; P = 0.002). Male participants in the trial group experienced significantly lower pain scores than the control group (mean difference -1.4, 95%CI -2.41 to -0.39; P = 0.008). The trial group showed significantly less variation in heart rates (P<0.001) and higher CEQ scores (P = 0.001) than the control group. No adverse events were reported. CONCLUSION: TENS-WAA effectively reduced pain during colonoscopy without anesthesia, especially in male participants, providing a promising noninvasive analgesic method.