A double-blind randomized trial of wound and intercostal space infiltration with ropivacaine during breast cancer surgery: effects on chronic postoperative pain.

BACKGROUND The efficacy of local anesthetic wound infiltration for the treatment of acute and chronic postoperative pain is controversial and there are no detailed studies. The primary objective of this study was to evaluate the influence of ropivacaine wound infiltration on chronic pain after breast surgery. METHODS In this prospective, randomized, double-blind, parallel-group, placebo-controlled study, 236 patients scheduled for breast cancer surgery were randomized (1:1) to receive ropivacaine or placebo infiltration of the wound, the second and third intercostal spaces and the humeral insertion of major pectoralis. Acute pain, analgesic consumption, nausea and vomiting were assessed every 30 min for 2 h in the postanesthesia care unit and every 6 h for 48 h. Chronic pain was evaluated 3 months, 6 months, and 1 yr after surgery by the brief pain inventory, hospital anxiety and depression, and neuropathic pain questionnaires. RESULTS Ropivacaine wound infiltration significantly decreased immediate postoperative pain for the first 90 min, but did not decrease chronic pain at 3 months (primary endpoint), or at 6 and 12 months postoperatively. At 3 months, the incidence of chronic pain was 33% and 27% (P = 0.37) in the ropivacaine and placebo groups, respectively. During follow-up, brief pain inventory, neuropathic pain, and anxiety increased over time in both groups (P < 0.001) while depression remained stable. No complications occurred. CONCLUSION This multicenter, prospective study shows that ropivacaine wound infiltration after breast cancer surgery decreased immediate postoperative pain but did not decrease chronic pain at 3, 6, and 12 months postoperatively.