Upper abdominal open surgery is associated with significant trauma, and postoperative pain management poses considerable challenges. The inflammatory response triggered by peritoneal incision and the transmission of visceral pain via the vagus nerve are key components of "surgical stress" and pain. A potential intervention strategy involves the local administration of anesthetic agents to suppress peritoneal overreaction and block the cascade of pro-inflammatory cytokines in related nerves. Liposomal bupivacaine, as a long-acting local anesthetic, may provide more prolonged postoperative analgesia compared to ropivacaine. Therefore, this trial aims to prospectively compare the analgesic efficacy and anti-inflammatory effects of the two drugs when administered as pre-closure preperitoneal infiltration. Secondary endpoints include opioid consumption, complication rates, and postoperative recovery indicators, to comprehensively evaluate their clinical value.

Patients undergoing upper gastrointestinal open surgery often experience moderate to severe postoperative pain, which not only hinders early recovery but also significantly impairs their quality of life. Ideal postoperative analgesia requires a balance between efficacy and safety, and preperitoneal local anesthetic administration serves as an effective strategy to achieve this goal. Compared to conventional local anesthetics, liposomal bupivacaine-as a novel sustained-release formulation-enables continuous drug release, extending the analgesic duration to 48-72 hours. This study aims to compare the postoperative analgesic effects of preperitoneal injection of liposomal bupivacaine versus ropivacaine in patients undergoing upper gastrointestinal open surgery.

This study employs a randomized controlled design. Participants will be stratified based on the type of surgical incision (midline or subcostal) and randomized into groups using a computer-generated random seed with permuted block randomization (variable block sizes of 2, 4). Prior to abdominal closure during surgery, the experimental group will receive liposomal bupivacaine injections into the preperitoneal space on both sides of the wound, while the control group will receive ropivacaine injections. Apart from this intervention, both groups will maintain identical protocols for anesthesia induction, maintenance, and postoperative systemic analgesia to accurately evaluate the relative efficacy of the two local analgesic agents.

Inclusion Criteria:

1. Aged 18 to 75 years; for those >70 years old, a Karnofsky Performance Status (KPS) score ≥80 is required.
2. Scheduled for elective upper abdominal laparotomy.
3. Surgical approach involving either a subcostal or midline incision.
4. Incision length between 15 and 30 cm.
5. American Society of Anesthesiologists (ASA) physical status classification of I to III.

Exclusion Criteria:

1. ASA Physical Status Class greater than III.

2. Pre-existing chronic pain with long-term opioid use (for >1 year).

3. Significant hepatic or renal impairment, or underweight status, defined as:

   Estimated glomerular filtration rate (eGFR) of <40 mL/min/1.73m²; Child-Pugh Class C; Body Mass Index (BMI) <18.5 kg/m².

4. Known allergy or hypersensitivity to the investigational drug or any of its excipients.

5. Pregnancy or lactation