Video-assisted thoracoscopic surgery (VATS) is less invasive compared to traditional thoracotomy, but it is still reported that the incidence of acute pain following VATS exceeds 80%. Inadequate postoperative analgesia may trigger a series of adverse physiological stress responses, increase the occurrence of postoperative complications, and affect the rehabilitation process. If acute pain is not managed promptly and sufficiently, nearly one-quarter of patients may develop chronic pain, impacting normal life and sleep quality after discharge. Acute pain after VATS is mainly caused by the release of inflammatory mediators after soft tissue injury at the surgical site, which activates peripheral pain receptors and leads to abnormal action potentials transmitted along A δ and C fibers. Inflammatory mediators released from the soft tissues around incisions not only significantly alters the chemical microenvironment at the peripheral terminals of nociceptors, directly inducing pain, but also sensitizes afferent fibers, contributing to peripheral sensitization. Incisional infiltration is the simplest, safest, and most effective anesthesia method for preventing incision pain after laparoscopic surgery but even using long-acting local anesthetics, the effectiveness of postoperative analgesia can only last for a relatively short period of time. To improve the efficiency of local incision infiltration in postoperative analgesia, at least two issues need to be addressed: prolonging the duration of analgesia and reducing inflammation of nerve surrounding tissues.

Numerous studies have shown that glucocorticoids not only can achieve anti-inflammatory and analgesic effects by inhibiting inflammatory cytokines and inflammatory responses but also can prolong the duration of action of local anesthetics. The investigators conducted a multicenter, prospective, randomized controlled clinical study to explore whether preemptive incisional infiltration with ropivacaine plus triamcinolone is superior to ropivacaine alone in relieving postoperative pain for adults undergoing VATS. The investigators also compare the effects of the two intervention measures on postoperative pain management, patient safety, and recovery quality.

Inclusion Criteria:

1. Patients scheduled for elective thoracoscopic wedge resection, segmentectomy, and lobectomy under general anesthesia;
2. Ages 18 to 64 years old
3. American Society of Anesthesiologists (ASA) physical status of I-III
4. Patients must be able to understand nature and potential personal consequences of the clinical trial and cooperation with follow-up investigations
5. signing of the informed consent form.

Exclusion Criteria:

1. History of allergies to experimental drugs such as opioids or steroids;
2. Alcohol abuse; Long term use of opioid drugs (exceeding 2 weeks or 3 days per week for more than 1 month); Suspected use of sedatives and analgesics; Use analgesic drugs within 24 hours before surgery; Patients undergoing steroid therapy;
3. Serious neurological disorders, severe liver and kidney dysfunction, heart failure, etc;
4. Unable to use pain assessment scale;
5. Pregnant or lactating patients.