Abstract
INTRODUCTION: Postoperative pain is common after surgery, with a high incidence and risk of becoming chronic. Current multimodal analgesia has drawbacks, including limited efficacy from single agents and opioid side effects and addiction risk. These issues have led to opioid-sparing multimodal analgesia. Transcutaneous auricular vagus nerve stimulation (taVNS) is non-invasive and convenient. Studies have shown it can reduce postoperative pain, improve mood and lower adverse events. However, taVNS lacks a comprehensive evaluation and standardised protocols, so further research is needed to provide reliable evidence. METHODS AND ANALYSIS: This study strictly adheres to the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. To identify suitable randomised controlled trials (RCTs), eight credible databases will be searched, including four English databases (Web of Science, PubMed, Cochrane Central Register of Controlled Trials, EMBASE) and four Chinese databases (China National Knowledge Infrastructure, VIP Database for Chinese Technical Periodicals, Wanfang Database, Chinese Biomedical Literature Database). RevMan V.5.3 will be employed to integrate the retrieved data and conduct meta-analyses. The methodological quality of included RCTs will be evaluated using the Cochrane Risk of Bias Assessment 2.0 tool. Additionally, the Grading of Recommendations, Assessment, Development and Evaluation system will be applied to assess the strength and certainty of the evidence. We will also conduct publication bias analyses, sensitivity analyses and subgroup analyses. ETHICS AND DISSEMINATION: No ethical review is required as no private or confidential patient data will be included. Results of this study will be disseminated through a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD420251207651.