The objective of this investigation was to evaluate the influence of Butorphanol on postoperative pain mitigation in patients undergoing microwave ablation for hepatic tumor. Employing a rigorously designed multicentral, randomized, and placebo-controlled format, patients subjected to microwave ablation were assigned randomly to either Butorphanol (experimental group) or normal saline (control group). Primary outcomes encompassed intraoperative pain levels assessed through patient-driven evaluation utilizing a 10-point visual analog scale (VAS). Secondary outcomes included postoperative pain levels at the 6-hour mark (VAS) and comprehensive pain assessment outcomes.

Inclusion Criteria:

patients performing Microwave Ablation sign the informed consent

Exclusion Criteria:

Patients with a body mass index > 30 kg/m2 a history of depression opioid dependence poorly controlled hypertension (systolic blood pressure > 180 mmHg) myocardial infarction severe liver disease significant abdominal pain before surgery patients with sensory system or language dysfunctions who could not cooperate to complete the scale pregnant women.