The feasibility and efficacy of perioperative auricular acupuncture technique via intradermal needle buried for postoperative movement-evoked pain after open radical gastrectomy: A randomized controlled pilot trial

Auricular acupuncture is widely used in the treatment of pain. Recently, the most commonly used method of auricular acupuncture is to embed an intradermal needle into the skin to enhance analgesia through continuous stimulation. We aimed to explore the efficacy and feasibility of this form of auricular acupuncture in the treatment of postoperative movement-evoked pain.This single-blind randomized controlled pilot trial was conducted between 23/8/2019 and 10/1/2020. Forty patients were recruited and randomised to either the control group (n = 20) or the experimental group (n = 20). Patients in the control group received sham auricular acupuncture, while patients in the experimental group received auricular acupuncture. A standard routine analgesia was performed in both groups. The patients with NRS score≥4 were given rescue analgesia. Postoperative pain, use of opioids and other analgesics, postoperative recovery and patient's satisfaction were recorded.The credibility and feasibility of auricular acupuncture for postoperative pain were high in both groups. After auricular acupuncture, the scores of the postoperative movement-evoked pain had a tendency to decrease, but no significant difference was observed between two groups at any time point (P = 0.234∼0.888). The data on postoperative pain at rest confirmed that no significant difference was observed between two groups within 48 h of surgery (P = 0.134∼0.520), and the postoperative pain at rest scores decreased over time; however, from the third day, the pain at rest scores of the experimental group were decreased, and significant differences were observed between the two groups (P = 0.039∼0.047). As for use of rescue analgesic, total opioid consumption and the incidence of postoperative nausea and vomiting, there were no significant differences between the two groups (P = 0.311, P = 0.101, P = 0.661) . In terms of patients' satisfaction, the score of the experimental group was higher than that of the control group, and a significant difference was observed between the two groups (P = 0.000). As for adverse events, two participants reported pain and one patient reported discomfort at the insertion sites during the process of auricular acupuncture intervention, but they both were minor and tolerable.Auricular acupuncture may have a relief effect on mild postoperative pain at rest with pain score below 3, suggesting that it may be a feasible adjuvant method to relieve mild pain at rest. However, more multi-centre and large-sample studies are needed to verify this result.