Effect of auricular point pressing therapy on postoperative pain of fracture

Abstract Background: In clinical practices, postoperative fracture patients are often treated with analgesics. As one of the alternative therapies for nondrug analgesia, auricular point pressing has advantages of simple operation, easy to use, no injury and adverse reactions, and great potential for development. In this study, the effect of auricular point pressing therapy on postoperative pain of fracture was objectively evaluated through the method of meta-analysis, so as to provide evidence for clinical applications. Methods: PubMed, Web of Science, Cochrane Library, EMBASE, Wan fang Database, Chinese Scientific Journal Database, China National Knowledge Infrastructure Database, and Chinese Biomedical Literature Database were systematically searched and randomized controlled trials on auricular point pressing in the treatment of postoperative pain after fracture were includes. After independent literature screening, data extraction and quality evaluation by 2 researchers, the original data was retrieved, merged, and analyzed. RevMan 5.3 software was adopted for meta-analysis Results: This study could provide high-quality evidence to evaluate the effect of auricular point pressing therapy on postoperative pain of fracture. Conclusion: This systematic review explored whether auricular point pressing therapy is effective on the intervention of postoperative pain after fracture. OSF Registration Number: DOI 10.17605/OSF.IO/AZ4JQ.


Introduction
The postoperative pain of fracture mainly is a certain degree of acute pain, and is a complex physiological reaction caused by body itself and surgical trauma. [1] Pain has become the fifth vital sign, followed by body temperature, pulse, breathing, and blood pressure. [2] At the same time, the pain after fracture can promote the release of various endogenous substances in human bodies, act on skeletal muscle, myocardial or vascular smooth muscle, increase peripheral circulation resistance, and produce adverse reactions such as elevated blood pressure and accelerated heart rhythm. [3] Postoperative fracture patients often take analgesics to relieve pain. Effective postoperative analgesia can reduce the secretion of catecholamine in patients, inhibit stress reaction, and contribute to the rehabilitation of patients. [4] However, improper administration of analgesics may cause adverse reactions such as gastrointestinal discomfort, liver and kidney function damage, cardiovascular system damage, and so on. [5][6][7] Auricular point therapy of Traditional Chinese Medicine (TCM) is one of the external therapies with the characteristics of TCM, including pressing, acupuncture, bloodletting, needle imbedding, Tuina, and other operations. [8][9][10] According to TCM, auricular points are specific acupoints distributed on the auricle of human body, and they are the reaction points of pathological changes of Zang-fu Organs and meridians and collaterals on body surface. [11,12] According to bioelectricity theory, the abnormal bioelectricity in pathological changes of the human body can cause the decrease of the resistance of corresponding auricular points. Related studies proved that after, 1 to 2 weeks of applying voltage to the auricle skin of peritonitis rats, the low resistance state of the skin around auricle improved. [13] Clinically, auricular point pressing is the most commonly applied auricular point stimulation method at present, with The systematic review will be published in a peer-reviewed journal, presented at conferences, and will be shared on social media platforms. This review would be disseminated in a peer-reviewed journal or conference presentations. This work is supported by the National Natural Science Foundation of China (NSFC 81700733).
The authors have no conflicts of interest to disclose.
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

Study Protocol Systematic Review
Medicine ® OPEN advantages of long-lasting effect, simple operation, and less side effects. [14] Clinical reports proved that this therapy plays a positive role in the intervention of headache, insomnia, and neurasthenia. [15][16][17] At present, the effect of auricular point pressing therapy on postoperative pain of fracture lakes metaanalysis, thus hindering the spread of evidence. Therefore, according to the objective clinical needs, this study conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) on the effect of auricular point pressing therapy on postoperative pain after fracture, so as to provide support for the spread of evidence.

Study registration
The protocol of this review was registered in OSF (OSF registration number: DOI 10.17605/OSF.IO/AZ4JQ). It was reported to follow the statement guidelines of preferred reporting items for systematic reviews and meta-analyses protocol. [

Searching strategy
The details of PubMed's search strategy are illustrated in Table 1, including all search terms, while similar search strategies are applied to other electronic databases.
2.5. Data collection and analysis 2.5.1. Selection of studies. Two researchers independently carried out literature screening, data extraction and cross-checking, and dissenting literatures or data were decided by the third researcher. According to the selection and exclusion criteria, the literature screening and data extraction were conducted strictly, and the whole screening and extraction process was recorded. The screening flow chart of this study is demonstrated in Figure 1.

Data extraction and management.
Two independent researchers extracted data from qualified literatures and filled out data collection forms. Any objection would be resolved by consensus or consultation with a third researcher. Excel 2013 was used for data management. We extracted the following data: title, first author, year of publication, country, journal, age, sex, sample size, inclusion and exclusion criteria, baseline, intervention details, follow-up time, outcome indicators, and bias risk. According to the criteria, the included studies were divided into 3 levels: low, medium, and high.

Measures of treatment effect.
Standard mean difference with 95% confidence intervals. was used as continuous data, and the dichotomous outcomes were estimated by the risk ratio with 95% confidence intervals.

Management of missing data.
If any data is missing, requesting the original data by email. If the missing data cannot be obtained, the data could be excluded from the study.

Assessment of heterogeneity and data synthesis.
Heterogeneity test: Q test was applied to qualitatively determine inter-study heterogeneity: If P ≥ .1, there is no inter-study heterogeneity, and if P < .1, there is inter-study heterogeneity. Meanwhile, I 2 value is adopted to quantitatively evaluate the inter-study heterogeneity: If I 2 50%, the heterogeneity is considered to be good, and the fixed-effect model would be adopted. If I 2 > 50%, it indicates significant heterogeneity, and the source of heterogeneity would be explored through subgroup analysis or sensitivity analysis. If there is no obvious clinical or methodological heterogeneity, it would be considered as statistical heterogeneity, and the random-effect model would be applied for analysis. Descriptive analysis would be used if there is significant clinical heterogeneity between the 2 groups, and subgroup analysis is not required.
2.5.7. Assessment of reporting biases. If more than 10 studies are included, a funnel chart would be utilized to assess the report bias. [19][20][21] In addition, publication bias was further quantitatively evaluated by Egger and Begger test.

Subgroup analysis.
When heterogeneity is discovered (such as different types of treatment, different types of fractures, patient age, and publication year), subgroup analysis would be applied to find out the source of heterogeneity.
2.5.9. Sensitivity analysis. Through the study of large weight of elimination effect, the sensitivity analysis was performed to test the stability of the results of meta-analysis.
2.5.10. Ethics and dissemination. The content of this article does not involve moral approval or ethical review and would be presented in print or at relevant conferences.

Discussion
Clinically, patients after fracture surgery are often treated with analgesics, including opioid analgesics and nonsteroidal antiinflammatory drugs. Improper administration of analgesics may cause adverse reactions such as tolerance, dependence, toxic reactions, mental reactions, gastrointestinal reactions, liver and kidney function damage, cardiovascular system damage, and so on. [22,23] With the change of modern medical model, orthopedic patients have higher requirements for nursing, and patients and medical staff are no longer satisfied with simple fracture healing. Instead, they pursue a series of physical and mental therapeutic effects, including pain management, functional rehabilitation, and orthopedic care. [24] Among them, the mode of pain management changed from a single mode with anesthesiologists as the main body to a combined mode with nurses as the main body. Auricular plaster therapy in TCM is a traditional and common therapy for nondrug analgesia. [25] It is easy to operate, without injury and rare adverse reactions. [26] Although many clinical studies confirmed that auricular point pressing therapy is effective for postoperative pain after fracture, its efficacy and safety are still controversial.
The purpose of this study was to systematically review and evaluate all RCTs of the effect of auricular point pressing therapy on postoperative pain after fracture. The systematic review and meta-analysis of this article provide convincing conclusions for the efficacy and safety of auricular point pressing therapy for the treatment of postoperative pain after fracture. In addition, this study helps clinical doctors and nurses to intervene postoperative pain of fracture, benefit patients, and provide reliable reference for its wide application.