This randomized controlled trial evaluates postoperative quality of recovery assessed with the Quality of Recovery-15 questionnaire in adult patients undergoing elective major urological surgery under opioid-free versus opioid-based general anesthesia.

Opioid-free anesthesia is a multimodal anesthetic technique that avoids intraoperative opioids by combining non-opioid analgesic and sympatholytic agents such as dexmedetomidine, ketamine, lidocaine, non-steroidal anti-inflammatory drugs, and regional analgesia. Opioid-based general anesthesia in this trial includes intraoperative remifentanil infusion.

Participants will undergo elective urological surgery, including laparoscopic nephrectomy, robotic nephrectomy, laparoscopic prostatectomy, robotic prostatectomy, laparoscopic cystectomy, or robotic cystectomy.

The primary objective is to compare patient-reported quality of recovery between the opioid-free anesthesia group and the remifentanil-based anesthesia group using the Quality of Recovery-15 questionnaire. QoR-15 will be assessed before surgery and on postoperative day 7.

Secondary objectives include total postoperative oxycodone dose administered via patient-controlled analgesia during the first 24 hours after surgery, postoperative pain intensity measured using the Numeric Rating Scale at 1, 2, 6, 12, and 24 hours after surgery, incidence of postoperative nausea and vomiting, change in serum creatinine from baseline to postoperative day 1, change in white blood cell count from baseline to postoperative day 1, and the ratio of demanded to delivered PCA boluses.

Pre-specified subgroup analyses will compare outcomes according to surgical procedure type: laparoscopic nephrectomy, robotic nephrectomy, laparoscopic prostatectomy, robotic prostatectomy, laparoscopic cystectomy, and robotic cystectomy. Subgroup-by-treatment interaction tests will be performed.

Planned enrollment is approximately 600 patients, with 300 patients per treatment arm. The primary patient-reported recovery endpoint will be assessed on postoperative day 7, while analgesic, pain, and early postoperative safety outcomes will be assessed during the first 24 hours after surgery.

This is a randomized, parallel-group, single-blind clinical trial evaluating postoperative quality of recovery assessed with the Quality of Recovery-15 questionnaire after opioid-free versus opioid-based general anesthesia in patients undergoing elective major urological surgery.

All consecutive adult patients scheduled for elective major urological surgery under general anesthesia will be screened for eligibility. Eligible surgical procedures include laparoscopic or robotic nephrectomy, laparoscopic or robotic prostatectomy, and laparoscopic or robotic cystectomy.

After providing written informed consent, participants will be randomly assigned to one of two treatment groups: opioid-free general anesthesia or opioid-based general anesthesia with intraoperative remifentanil.

In the opioid-free anesthesia group, anesthesia will be conducted without intraoperative opioids. The anesthetic protocol includes multimodal non-opioid analgesia using dexmedetomidine, ketamine, lidocaine, non-opioid analgesics, and procedure-specific regional analgesia. Sevoflurane will be used for maintenance of general anesthesia.

In the opioid-based anesthesia group, general anesthesia will include intraoperative remifentanil infusion. Sevoflurane will be used for maintenance of anesthesia. Standard non-opioid co-analgesics and procedure-specific regional analgesia will also be used according to the study protocol.

Regional analgesia will be selected according to the surgical procedure. Patients undergoing nephrectomy will receive bilateral erector spinae plane block. Patients undergoing prostatectomy will receive bilateral quadratus lumborum block. Patients undergoing cystectomy will receive continuous epidural analgesia with ropivacaine.

In the postoperative period, all patients will receive standardized analgesia. Postoperative analgesia will include oxycodone administered via patient-controlled analgesia or oral oxycodone/naloxone when appropriate, together with non-opioid co-analgesics such as paracetamol and metamizole. The PCA regimen will consist of oxycodone boluses of 2 mg, a 10-minute lockout interval, and no background infusion.

The main patient-reported outcome will be quality of postoperative recovery assessed with the Quality of Recovery-15 questionnaire. QoR-15 will be completed before surgery and on postoperative day 7. The postoperative day 7 QoR-15 total score and the change in QoR-15 score from baseline to postoperative day 7 will be compared between the opioid-free anesthesia group and the remifentanil-based anesthesia group.

Postoperative pain intensity will be assessed using the Numeric Rating Scale at 1, 2, 6, 12, and 24 hours after surgery. Total oxycodone consumption via PCA during the first 24 hours after surgery will be recorded. The numbers of demanded and delivered PCA boluses will be recorded to calculate the demanded-to-delivered bolus ratio. Postoperative nausea and vomiting will be assessed during the first 24 hours after surgery.

Laboratory outcomes will include serum creatinine and white blood cell count measured before surgery and on postoperative day 1.

Pre-specified subgroup analyses will be performed according to the type and surgical approach of the procedure: laparoscopic nephrectomy, robotic nephrectomy, laparoscopic prostatectomy, robotic prostatectomy, laparoscopic cystectomy, and robotic cystectomy. Treatment-by-subgroup interaction tests will be performed.

Inclusion Criteria:

• Adults aged 18 to 75 years.
• Scheduled for elective major urological surgery under general anesthesia, including laparoscopic or robotic nephrectomy, laparoscopic or robotic prostatectomy, or laparoscopic or robotic cystectomy.
• Ability to operate a patient-controlled analgesia pump postoperatively.
• Ability to understand and use the Numeric Rating Scale for pain assessment.
• Ability to understand and complete the Quality of Recovery-15 questionnaire.
• Written informed consent.

Exclusion Criteria:

• Patient refusal to participate.
• Inability to operate the patient-controlled analgesia pump.
• Inability to understand the Numeric Rating Scale for pain assessment.
• Inability to understand or complete the Quality of Recovery-15 questionnaire.
• Known hypersensitivity to any of the study drugs, including anesthetics, ketamine, dexmedetomidine, lidocaine, ropivacaine, oxycodone, metamizole, paracetamol, or ibuprofen.
• Second- or third-degree atrioventricular block.
• Symptomatic bradycardia.
• Chronic opioid use.
• Contraindication to the planned regional anesthesia technique, including coagulopathy, therapeutic anticoagulation, or infection at the puncture site.

De-identified individual participant data will be shared, including demographic data, type of surgery, treatment allocation, Quality of Recovery-15 questionnaire scores, postoperative pain scores, opioid consumption, patient-controlled analgesia use data, postoperative nausea and vomiting

Data will become available after completion of the study and publication of the primary results, anticipated in 2026, and will remain available for 1 year.

Data will be made available to qualified researchers upon reasonable request for scientific purposes, after approval by the principal investigator and, where required, by the relevant ethics committee. Data will be shared in de-identified form.