Transcutaneous auricular vagus nerve stimulation (taVNS) is a novel pain management technique that has gained popularity in recent years due to its non-invasive nature and ease of operation. Current literature has substantiated its efficacy in managing pain syndromes and chronic pain. However, there is a paucity of evidence regarding its effectiveness in treating acute postoperative pain. This project aims to explore the efficacy of taVNS in postoperative pain management, with a focus on video-assisted thoracic surgery(VATS). The investigators have designed a double-blind, single-center, randomized controlled clinical trial, planning to enroll 116 patients scheduled to undergo VATS(including segmentectomy or lobectomy) under general anesthesia at Peking Union Medical College Hospital. Participants will be divided into an intervention group (receiving taVNS) and a sham intervention group (receiving sham-taVNS), and will undergo a 2-hour intervention on the first postoperative day. The primary outcome is the pain relief rate, defined as a reduction of 15mm or 30% in the VAS (1-100mm) score immediately before and after the intervention on the first postoperative day. Secondary outcomes include: the proportion of patients with inadequate analgesia within three days after intervention; the difference in VAS scores immediately before and after the intervention on the first postoperative day; the incidence of opioid-related and taVNS-related side effects from the first to the third postoperative day after intervention; the number of effective and ineffective PCA presses (if used) from the first to the third postoperative day after intervention; the specifics and frequency of additional analgesic measures taken by patients from the first to the third postoperative day after intervention; the difference in RCSQ scores on the night of surgery and the night after intervention; and the probability of patients experiencing surgery-related pain three months after surgery. Follow-up period for this study will be three months after surgery.

Inclusion Criteria:

1. Age 18 years or older;
2. ASA classification I-III;
3. No prior taVNS treatment;
4. Scheduled to undergo VATS (including segmentectomy and lobectomy);
5. VAS ≥ 30 mm at any time on the day of surgery;
6. Patients and their families can understand the study design and are willing to cooperate and participate in the study.

Exclusion Criteria:

1. Psychiatric disorders or other conditions that prevent cooperation;
2. Long-term use of steroids or opioids;
3. Scheduled for bilateral VATS surgery;
4. History of thoracic surgery;
5. History of chronic pain, autoimmune diseases, or persistent infections.

Withdrawl Criteria:

1. Patient request;
2. Surgery cancellation or change in surgical method resulting in failure to meet inclusion criteria;
3. Severe perioperative complications and adverse events;
4. Severe intervention-related adverse events.

Considering patients' privacy and the measures for protecting participants, we do not plan to disclose patients' personal data.