Wound infusion of bupivacaine following radical retropubic prostatectomy: a randomised placebo-controlled clinical study.

Context: The effectiveness of postoperative analgesia through a wound catheter is subject to considerable debate.
Objective: To test the hypothesis that local wound infusion with bupivacaine followed by continuous infusion could reduce postoperative need for opioids in patients undergoing retropubic prostatectomy.
Design: Single-centre prospective, double-blinded, placebo-controlled trial.
Setting: A major university hospital in Denmark.
Patients: Following written informed consent, 60 patients scheduled for prostatectomy were recruited to the study and 50 completed the protocol to reach data analysis.
Interventions: Thirty millilitre bolus of bupivacaine (2.5 mg ml) or isotonic saline was injected through a subfascially placed wound catheter followed by continuous infusion at 5 ml h during the following 48 h. All patients were prescribed paracetamol, non-steroidal anti-inflammatory drugs, morphine and oxycodone if needed.
Outcome Measures: Primary outcome was the opioid requirement. Secondary outcomes included pain scores at rest and with activity, and nausea and vomiting scores.
Results: The total amount of morphine required during the postoperative period was not significantly higher (P=0.49) in the placebo group (12 mg, 25 to 75% percentile 5 to 18) than the bupivacaine group (10 mg, 25 to 75% percentile 0 to 16). Similarly, the total amount of oxycodone required was not significantly different (P=0.99) and was equal among the groups (5 mg, 25 to 75% percentile 5 to 10). At 2 h postoperatively, a significantly (P=0.0488) higher number of patients required additional morphine in the placebo group. No differences between the groups were detected at any time point regarding pain scores or the presence of nausea and vomiting.
Conclusion: Additional use of a wound catheter in patients undergoing prostatectomy in the present perioperative setting appears superfluous.