Epidural block with mepivacaine before surgery reduces long-term post-thoracotomy pain

Purpose: To examine the effect of continuous epidural block initiated before thoracic surgery upon early and long-term postoperative pain. Methods: In a double-blind study, 70 patients scheduled for thoracic surgery under general anesthesia were assigned randomly to receive continuous epidural block with mepivacaine 1.5% initiated either 20 min before surgical incision (Pre group) or at completion of surgery (Post group). In both groups the initial dose was 4 mt, followed by a continuous infusion at 4 ml.hr(-1) until 72 hr after operation. Indomethacin suppositories, 50 mg, were administered on request as supplementary analgesics. Visual analogue scale at rest was assessed four hours after operation, and then every 24 hr after operation on postoperative days I through 7, and also days 14 and 30. At three and six months after operation, all patients were interviewed by telephone with respect to postoperative pain. The most severe pain was assessed using modified numerical rating scale. Results: By a visual analogue scale, postoperative pain was less in the Pre group than in the Post group at four hours, two and three days after operation (P < 0.05). By a numerical rating scale six months after operation, pain was less in the Pre group than in the Post group (P = 0.015). The percentage of pain-free patients was higher in the Pre group than in the Post group at three (P = 0.035) and six (P = 0.0086) months after operation. Conclusion: Continuous epidural block initiated prior to surgery may reduce long-term post-thoracotomy pain.