Effectiveness of continuous wound infusion of 0.5% ropivacaine by On-Q pain relief system for postoperative pain management after open nephrectomy

Background. Block of parietal nociceptive afferent nerves using continuous wound infiltration with local anaesthetics may be beneficial in multimodal postoperative pain management. The effectiveness of continuous wound infusion of ropivacaine for postoperative pain relief after open nephrectomy was analysed in a prospective, randomized, double-blinded, placebo-controlled trial. Methods. One hundred and sixty-eight patients were randomized to either 0.5% ropivacaine (ON-Q group) or 0.9% NaCl (control group), using an elastomeric pump which delivered 4 ml h^-1 over 48 h through two multiholed Soaker® catheters placed between the transverse and the internal oblique muscles and the s.c. space. All patients received a standard postoperative pain management protocol, including patient-controlled analgesic morphine and ketorolac. Outcomes measured over 48 h after operation were visual analogue scale (VAS) and incident (i) VAS pain scores, morphine consumption, and side-effects; time to bowel function recovery; and mean length of hospitalization. Results. Side-effects were similar between the two groups. VAS and i-VAS pain scores, morphine consumption [11.5 (0.27) vs 21.8 (0.37) mg; P