Opioid-free versus opioid-based anesthesia for robot-assisted radical prostatectomy: a single-center randomized controlled trial

Multimodal, opioid-sparing analgesia is standard in urological surgery, and there is additional interest in eliminating intraoperative opioids in prostate cancer surgery. Randomized evidence for opioid-free anesthesia (OFA) in robot-assisted radical prostatectomy (RARP) is lacking. In this single-center randomized controlled trial, adult men undergoing RARP were allocated 1:1 to OFA (dexmedetomidine plus ketamine, no intraoperative opioids) or a remifentanil-based technique. Both groups received identical multimodal premedication, a bilateral quadratus lumborum block, sevoflurane maintenance and identical oxycodone patient-controlled analgesia (PCA). The primary outcome was cumulative PCA oxycodone consumption over the first 24 postoperative hours. Prespecified secondary outcomes were pain (NRS), postoperative nausea and vomiting (PONV), the demanded-to-delivered PCA bolus ratio, and perioperative changes in serum creatinine and white-cell count. A total of 149 patients were analyzed (OFA n=75, opioid-based n=74). Cumulative 24-h oxycodone consumption was lower with OFA (median 12.0 mg [interquartile range, IQR 6.0-22.0] vs 19.0 mg [10.5-34.0]; p=0.001), with a Hodges-Lehmann location-shift estimate of -6.0 mg (95% confidence interval, CI -10.0 to -2.0). Pain scores did not differ at any time point, and PONV was infrequent, with no significant between-group difference. Intraoperative hemodynamic adverse events (bradycardia, hypotension), perioperative white-cell count and serum creatinine did not differ between groups. In RARP delivered on a standardized multimodal and regional analgesic background, OFA reduced postoperative opioid consumption compared with a remifentanil-based technique, without a detectable difference in pain scores and with a similar safety profile.Trial registration ClinicalTrials.gov NCT06380244, registered 23 April 2024.