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.

All consecutive patients undergoing elective urological surgery (laparoscopic or robotic nephrectomy, prostatectomy, or cystectomy) will be randomly divided into two groups: one under completely opioid-free anesthesia (infusion of ketamine, lidocaine and dexmedetomidine, with inhalation of sevoflurane) and the other under combined general anesthesia (using an infusion of remifentanil intraoperatively). In the postoperative period, all patients will receive oxycodone in a PCA pump or in the form of oral tablets [oxycodone hydrochloride + naloxone hydrochloride] and co-analgesics in the form of paracetamol and metamizole.

Opioid-free general anesthesia is a recognized method used during anesthesia. It allows participants to effectively control pain, reducing the number of complications associated with taking large doses of opioid drugs. It should be emphasized that it is approved for use in routine anesthetic practice, and whether such a technique is used in a given patient depends on the experience, knowledge and preferences of the anesthesiologist. It is used in everyday anesthetic practice, but there is no conclusive scientific data confirming its advantage in patients undergoing major urological surgery.

Mulier et al. proposed an OFA scheme including dexmedetomidine, ketamine and lidocaine for the induction of anesthesia, ensuring sedation, analgesia and sympatholytic therapy, followed by a maintenance infusion of lidocaine and dexmedetomidine. The protocol proposed by Mulier et al. is widely used and accepted worldwide. Initially used in patients undergoing bariatric procedures, it was subsequently extended to other types of surgical procedures.

In the postoperative period, pain will be assessed using the NRS scale at 1, 2, 6, 12, and 24 hours after the procedure. Serum creatinine and white blood cell (WBC) count will be measured preoperatively (baseline) and on postoperative day 1.

Inclusion Criteria:

• Adults aged 18-75 years scheduled for elective urological surgery under general anesthesia: laparoscopic or robotic nephrectomy, laparoscopic or robotic prostatectomy, or laparoscopic or robotic cystectomy.
• Ability to operate a patient-controlled analgesia (PCA) pump postoperatively.
• Ability to understand and use the Numeric Rating Scale (NRS) for pain assessment.
• Written informed consent.

Exclusion Criteria:

• Patient's refusal to participate.
• Inability to operate the PCA pump.
• Inability to understand the NRS pain scale.
• Known hypersensitivity to any of the study drugs (anesthetics, ketamine, dexmedetomidine, ropivacaine, oxycodone, metamizole, paracetamol, ibuprofen).
• Second- or third-degree atrioventricular block, or symptomatic bradycardia.
• Chronic opioid use.
• Contraindication to the planned regional anesthesia technique (e.g. coagulopathy or therapeutic anticoagulation, infection at the puncture site).

We plan to share demografic data, type of surgery, score in NRS and opioid consumption dosage.

The data will be available in 2026 for 1 year