Transcutaneous electrical acupoint stimulation before surgery reduces chronic pain after mastectomy: A randomized clinical trial

Despite multiple interventions, the incidence of chronic pain after mastectomy could be as high as 50% after surgery. This study aimed to determine the efficacy of transcutaneous electrical acupoint stimulation (TEAS) before anesthesia induction in reducing chronic pain and to compare the effect of combined acupoint TEAS with that of single acupoint TEAS. A multicenter randomized clinical trial. The study was conducted at six medical centers in China from May 2016 to April 2018. Final follow-up was on October 26, 2018. Eligible patients were women scheduled for radical mastectomy under general anesthesia. Patients were randomly and equally grouped into sham control (n = 188), single acupoint (PC6, n = 198), or combined acupoints (PC6 and CV17, n = 190) TEAS groups using a centralized computer-generated randomization system. TEAS was applied for 30 min before anesthesia induction. The sham-operated control group received electrode attachment but without stimulation. Anesthesiologists, surgeons, and outcome assessors were blinded to the interventions. The primary endpoint was the incidence of chronic pain 6 months after surgery. Incidences were compared among the groups using the unadjusted χ2 test. Of the 576 randomized patients, 568 completed the trial. In the intention-to-treat analysis, post-mastectomy pain at 6 months was reported in 42 of 190 patients (22.1%) in the combined acupoints group, 65 of 188 patients (34.6%) in the sham-operated group (P = 0.007; relative risk [RR], 95% confidence interval [CI]: 0.68, 0.52–0.89), and 72 of 198 patients (36.4%) in the single acupoint group (P = 0.002; RR, 95% CI: 0.72, 0.55–0.93). Remifentanil consumption during surgery and postoperative nausea and vomiting at 24 h after surgery were lower in the combined acupoint group than that in the sham-operated group. TEAS at combined acupoints before surgery was associated with reduced chronic pain 6 months after surgery. Trial registration: Clinicaltrials.gov identifier: NCT02741726. Registered on April 13, 2016.