Opioid-free Anesthesia as an Alternative to General Anesthesia in Abdominal Surgery

Opioid-free anesthesia (OFA) is a multimodal technique that eliminates intraoperative opioids by combining dexmedetomidine, ketamine, lidocaine, NSAIDs, and regional analgesia. Growing evidence suggests OFA reduces postoperative opioid consumption, opioid-related adverse effects, and may have favorable oncological implications in cancer surgery. This randomized controlled trial compares OFA with opioid-based anesthesia (remifentanil) in patients undergoing elective urological surgery: laparoscopic nephrectomy, robotic nephrectomy, laparoscopic prostatectomy, robotic prostatectomy, laparoscopic cystectomy, and robotic cystectomy. The PRIMARY OBJECTIVE is to compare the total postoperative oxycodone dose (mg) administered via patient-controlled analgesia (PCA) during the first 24 hours after surgery between the OFA and remifentanil groups. SECONDARY OBJECTIVES include: postoperative pain intensity (NRS) at 1, 2, 6, 12, and 24 hours; incidence of postoperative nausea and vomiting (PONV); change in serum creatinine from baseline to postoperative day 1; change in white blood cell (WBC) count from baseline to postoperative day 1; and the ratio of demanded to delivered PCA boluses. PRE-SPECIFIED SUBGROUP ANALYSES will compare outcomes by surgical procedure type: laparoscopic nephrectomy, robotic nephrectomy, laparoscopic prostatectomy, robotic prostatectomy, laparoscopic cystectomy, and robotic cystectomy. Subgroup-by-treatment interaction tests will be performed and reported as forest plots. Planned enrollment: approximately 600 patients (300 per arm). Follow-up: 24 hours postoperatively.