Liposomal vs. Conventional Bupivacaine for Pain Control

Inclusion Criteria: * Age between 18 and 70 years old. * Scheduled for laparoscopic-assisted unilateral radical nephrectomy. * Agree to undergo regional nerve blockade and receive patient-controlled intravenous analgesia after surgery. Exclusion Criteria: * Renal cancer with venous thrombus of grade II or higher, or cases that may convert to open surgery. * Body mass index ≥30 kg/m² or ≤15 kg/m². * Severe renal dysfunction (serum creatinine \>442 μmol/L or requiring renal replacement therapy), severe liver dysfunction (Child-Pugh class C), or American Society of Anesthesiologists class ≥IV. * Contraindications for deep nerve block, including severe spinal deformity or history of spinal surgery, severe coagulation abnormalities (international normalized ratio \>1.7, activated partial thromboplastin time \>4 seconds above normal, platelet count \<80×10⁹/L), trauma or infection at the planned puncture site, or severe lumbar back pain. * Chronic opioid dependence and long-term use of various analgesics for more than 3 months. * Preoperative inability to communicate due to severe dementia, language barriers, or end-stage diseases. * Preoperative concomitant central nervous system and/or peripheral nervous system diseases. * Planned endotracheal intubation and admission to the intensive care unit after surgery. * Known allergy to local anesthetics. * Other conditions that are deemed unsuitable for trial participation by the attending surgeons or investigators.