Postoperative Analgesic Efficacy of Ear Acupuncture in Patients Undergoing Abdominal Hysterectomy

A Randomized Controlled Trial

Hamdy A. Hendawy; Mohamed E. Abuelnaga


BMC Anesthesiol. 2020;20(279) 

In This Article


Acupuncture and TENS were proven to increase the threshold of somatic pain. Ishimaru and colleagues examined how low flow electric acupuncture (LFEA) can influence pain threshold in the abdominal area; they advocated that LFEA can be helpful for analgesia following abdominal surgery.[16]

The effect of LFEA and TENS on the deep pain threshold at the skin surface and deeper layers has been examined by a few studies.[17,18] Kitade and colleagues found an increased pain threshold for 50 min following LFEA, with no identified increase in the levels of plasma β-endorphin or adrenocorticotropic hormone in the cerebrospinal fluid.[19] These results eliminate the role of β-endorphin in the analgesic effect of acupuncture. Because acupuncture analgesia was offset by naloxone, there is a probability that some types of endogenous opioid peptides are responsible for the analgesic effect of acupuncture. Ishimaru et al. showed that 30 min of LFEA produced analgesia.[20] They found increased levels of plasma β-endorphin,[20,21] with no change in plasma adrenocorticotropic hormone level.[21] This result matches what has been found in patients with post-operative pain.[21]

Several mechanisms for acupuncture pain have been reported as the release of spinal natural opioids like dynorphin, endorphin, and encephalin, which are potent pain suppressors, increase in local blood flow that encourages the process of healing, gate control theory of pain, the endogenous release of adrenocorticotrophic hormones, myofibrillary entanglement relaxation, and creating a balance in the mesolimbic neural pain pathway.[22]

In 2016, De Freitas et al., have reported in an animal study that acupuncture has a pre-emptive analgesic effect.[23] Sim et al. 2002 compared preoperative versus postoperative body EA for lower abdominal gynaecologic surgery. Preoperative acupuncture was found to be more effective in reducing postoperative morphine consumption in these patients.[11]

In the current study, we decided to use preoperative EEA along with continuous postoperative acupoint stimulation by press needles to achieve the maximum analgesic effect. Our study demonstrated that the total postoperative PCA morphine consumption in the first 24 hours was reduced in the EEA group versus the control group; also the time of the first request for supplemental analgesia was delayed in the EEA group when compared with the control group.

Similar to our findings: In a prospective, randomized study done by WU Hung-Chien et al.[15] and conducted for 60 primigravida women scheduled for cesarean section under spinal anesthesia. Patients were allocated to one of three groups: control group, acupuncture group, and electro-acupuncture group. Acupuncture was started postoperatively after recovery from anesthesia and was applied for San yin Jiao (Sp6) body acupoint for 30 min. The results showed delayed first analgesic request in both the electro-acupuncture group (39.5 ± 16.9 min) and the acupuncture group (40.3 ± 13.8 min) versus the control group (29.0 ± 15.0 min). The total PCA morphine consumption during the first 24 postoperative hours was much reduced in the acupuncture group (10.66 ± 4.68) mg, and the electroacupuncture was (9.89 ± 5.18) mg than in the control group was (15.28 ± 4.99) mg.[15]

In our study, we had a delayed first morphine request and less total morphine dose which may be due to our usage of diclofenac potassium by intramuscular injection, the pre-emptive effect of acupuncture, and also acupuncture needles were replaced in the EEA group by press needles.

In our study, the VAS pain scores were lower in the EEA group versus the control group. Similarly, WU Hung-Chien, et al.[15] found that VAS pain scores were significantly lower in the auricular acupuncture group versus the control group at 0.5, 1, 1.5, and 2 hours in the postoperative period.

Similarly, Iacobone, m et al. 2014,[24] found less postoperative pain scores and reduced postoperative acetaminophen consumption in acupuncture treated groups versus the control group in patients undergoing thyroidectomy under general anesthesia.

Chen, C. C et al., 2015,[25] have investigated the effect of acupuncture on Pain Relief following total knee arthroplasty in a randomized controlled trial. The total amount of postoperative fentanyl consumption was found much reduced in the acupuncture group in comparison with the control group [mean (SD), 620.7 (258. 2) vs. 868.6 (319.3) μg, respectively, as well as delayed first request for fentanyl [median time, 89 vs. 37 min], in the acupuncture group and the control group respectively. Postoperative pain scores were much reduced in the acupuncture group versus the control groups at 2, 4, 8, 12, and 24 hours. Dingmann, J et al. 2017,[26] have found in their study the efficacy of acupuncture in reducing postoperative swallowing pain scores following tonsillectomy in patients aged 16 years or more.

In our study, there was a statistical difference between both groups as regards the incidence of nausea at some time points in the favor of the EEA group; also we found a significant difference between both study groups concerning the incidence of vomiting after 6 h in the favor of acupuncture group. This may be explained by a reduced total amount of 24 hours of morphine consumption in the acupuncture group in comparison to the control group.

Usichenk et al. 2004[27] found that auricular acupuncture (AA) is effective in the treatment of various pain conditions. They conducted a blinded study to assess the analgesic effect of AA for pain management following total hip arthroplasty. The patients were randomly assigned to receive either true AA or sham acupuncture, with press acupuncture needles kept in place for 3 postoperative days. Thirty-six hours of analgesic requirement following surgery was lower in the AA group versus the control group. No difference was found between both groups as regard VAS Pain scores or analgesia-related adverse effects.

Chang et al. 2012[28] have conducted a randomized controlled study to investigate the potential benefits of auricular acupressure for postoperative pain relief and ameliorating the passive range of motion in patients who underwent total knee replacement (TKR). Sixty-two patients were randomly allocated to either the acupressure group or the control group. The acupressure was performed three times a day for 3 days. The patients in both groups were found to have a comparable high level of postoperative pain scores. However, analgesic drug consumption was markedly reduced in the acupressure group versus the control group (P < 0.05), with markedly improved passive knee motion by the third postoperative day in patients treated with acupressure (P < 0.05).[28]

Lastly, we have some limitations. The analgesic effect found in the current study can be the result of either preoperative EEA, continuous post-operative acupoint stimulation by press needles, or combined effect of both techniques. Comparison between EEA and pressure acupuncture in the same acupoints is recommended in future studies. The other limitation in the current study was the use of a single postoperative non-opioid analgesic. In future studies, at least two non-opioid analgesics should be used to determine the real influence of acupuncture on postoperative analgesia requirements.