Comparison of a Non-Opioid Multimodal Analgesia Protocol with Opioid-Based Patient-Controlled Analgesia for Pain Control Following Robot-Assisted Radical Prostatectomy: A Randomized, Non-Inferiority Trial

BACKGROUND: Opioid use after surgery is a potential contributor to the opioid epidemic. An adequate pain control method after surgery while minimizing opioid exposure is needed. This study aimed to compare the effect of non-opioid multimodal analgesia (NOMA) protocol with opioid-based patient-controlled analgesia (PCA) for pain relief after robot-assisted radical prostatectomy (RARP). METHODS: This prospective randomized, open, non-inferiority trial included 80 patients scheduled for RARP. The NOMA group received pregabalin, paracetamol, bilateral quadratus lumborum block, and pudendal nerve block. PCA group received PCA. Pain scores, postoperative nausea and vomiting, opioid requirements, and quality of recovery were recorded 48 hours after surgery. RESULTS: We found no significant differences in pain scores. The mean difference in pain score during rest at 24 h was 0.5 (95% CI −0.5 to 2.0). This result demonstrated the non-inferiority of NOMA protocol to PCA at our non-inferiority margin (−1). In addition, 23 patients in the NOMA group did not receive any opioid agonist for 48 h after surgery. Recovery of bowel function was also faster in the NOMA group than in the PCA group (25.0 hours vs 33.4 hours, p = 0.01). LIMITATIONS: We did not evaluate whether our NOMA protocol could decrease the incidence of new continuous opioid use after surgery. CONCLUSION: NOMA protocol successfully controlled postoperative pain and was non-inferior to morphine-based PCA regarding patient-reported pain intensity. It also promoted recovery of bowel function and decreased postoperative nausea and vomiting.