Auricular acupuncture for postoperative pain control: a systematic review of randomised clinical trials

Pain after surgery is a common concern for both patients and health professionals, leading to a constant search for effective and safe methods of control. Among the complementary approaches, auricular acupuncture has aroused growing interest in the hospital setting. This specific acupuncture technique consists of inserting needles into specific points of the ear, based on the theory that different regions of this organ correspond to specific parts of the body. In recent years, the number of studies on the use of auricular acupuncture in the postoperative period has increased significantly, reflecting both medical interest and patient demand for alternatives in pain management.

Postoperative pain represents an interesting model for testing the efficacy of this technique, as it allows standardized comparisons among different groups of patients undergoing similar procedures.

To scientifically evaluate the efficacy of auricular acupuncture in postoperative pain control, international researchers conducted a systematic review of all randomized clinical trials available up to September 2007. The methodology involved a comprehensive search of various medical databases, including Medline and other specialized sources, using terms such as auricular acupuncture, postoperative pain, and clinical trials. Only prospective, controlled, and randomized studies that compared auricular acupuncture with other interventions in patients after surgery were included. To ensure the quality of the analysis, the researchers used the Jadad scale, an internationally recognized tool that assesses the risk of bias in clinical studies on a scale from zero to five points, considering factors such as adequate randomization, double-blinding, and clear description of methods.

The main outcomes analyzed were pain intensity and the need for analgesic medications after surgery.

The initial search identified 23 articles, of which only nine met the rigorous inclusion criteria of the review. These studies involved different types of surgery, ranging from cardiothoracic procedures to dental extractions, knee arthroscopies, and gynecological surgeries. In eight of the nine studies analyzed, auricular acupuncture was shown to be superior to the control groups, either reducing the intensity of pain or decreasing the need for analgesic medications. The studies varied in their methodologies, with some using specific ear points based on traditional theory, others applying electrical stimulation to the needles, and some keeping the needles fixed for periods ranging from a few hours to three days after surgery.

The methodological quality of the studies, assessed by the Jadad scale, ranged from one to four points, and none reached the maximum score of five points. It was observed that the more recent studies tended to show greater methodological rigor compared with the older ones.

The implications of these results for patients and health professionals are promising but should be interpreted with caution. For patients undergoing surgery, auricular acupuncture may represent a safe complementary option in postoperative pain management, potentially reducing dependence on analgesic medications and their associated side effects. The technique is relatively simple to apply, minimally invasive, and can be easily integrated into existing hospital protocols. For health professionals, especially anesthesiologists and surgical teams, these findings suggest that auricular acupuncture can be considered as part of a multimodal approach to postoperative pain control.

This is particularly relevant in the current context of the search for strategies that reduce the use of opioids, given the growing knowledge about their risks of dependence and other adverse effects. The technique also offers practical advantages, such as ease of application and low cost, making it accessible in different health care settings.

However, several important limitations must be considered. The main methodological concern identified was the difficulty in maintaining complete blinding in the studies, especially with respect to the practitioners applying the technique, which can introduce bias into the results. In addition, the studies showed great heterogeneity in terms of populations studied, types of surgery, acupuncture protocols, and assessment methods, preventing the performance of a more robust statistical meta-analysis. The relatively small sample size of many studies also limits the reliability of the conclusions.

Another important aspect is that most of the studies of higher methodological quality came from only two research groups, indicating the need for independent replication of the results. The theoretical basis of auricular acupuncture also remains controversial, since there are no clear anatomical pathways that directly connect internal organs with specific ear points, as postulated by the theory underlying the technique.

In conclusion, although the results of this systematic review are encouraging and suggest that auricular acupuncture may be beneficial in postoperative pain control, the scientific evidence is not yet definitive. The findings indicate promising but not conclusive potential for this therapeutic approach. Patients interested in this option should discuss with their physicians the possible benefits and limitations, considering it as a complement to, and not a substitute for, conventional pain control methods. For auricular acupuncture to be more consistently recommended in clinical practice, future studies with greater methodological rigor, larger samples, better control of bias, and independent replication of results by different research groups are needed.

Until more robust evidence is available, auricular acupuncture remains an interesting complementary option, but one that requires careful case-by-case evaluation.