Intraoperative wound infiltration with bupivacaine in patients undergoing lumbar spine surgery

We conducted a randomized double-blind trial to evaluate the effect of intraoperative wound infiltration with bupivacaine 0.25% (1 ml/kg) compared to placebo (NaCl 0.9% 1 ml/kg) in patients undergoing lumbar spine surgery. Fifty-two patients were entered in the trial and 50 completed it. Two methods of wound infiltration were assessed: (a) infiltration after partial wound closure and (b) infiltration prior to wound closure. Postoperatively patients received morphine sulfate on demand. Visual analog pain scores were recorded every 2 h for 12 h after the operation. Analgesia requirements were recorded over the duration of the study for each patient. The patients who received bupivacaine infiltration prior to wound closure had significantly reduced pain scores in the recovery room and used significantly less morphine in the first 2 h following the procedure. They also had reduced pain scores and reduced morphine demand in the first 10 h but this did not reach statistical significance. No difference was noted between the placebo group and those receiving infiltration after partial wound closure. It is concluded that infiltration of bupivacaine is a simple and safe aid in obtaining analgesia in patients undergoing lumbar spine surgery provided that it is infiltrated prior to wound closure.