Epidural morphine for pain relief after lumbar laminectomy.

A prospective randomized trial was conducted to evaluate the effectiveness of epidural morphine for pain relief after lumbar laminectomy. Thirty-three male patients were studied in two groups. At the end of surgery, Group 1 patients (15) received 2 mg morphine in 5 ml saline through an epidural catheter. Doses were repeated on demand. Group 2 patients (18) received 10 mg morphine intramuscularly on request in the postoperative period. Pain was assessed at 2, 6, 12, and 24 hours postoperatively by the linear analog of pain scale. There was significantly greater pain relief in Group 1 than in Group 2 after 2, 6, and 12 hours, respectively. Furthermore, Group 2 received larger doses of morphine than Group 1. There was no respiratory or cardiovascular depression detected in patients in either group. Nine patients in Group 1 and five patients in Group 2 had transient postoperative urinary retention that required catheterization. Only one patient in Group 1 had mild pruritus and three patients in Group 2 had nausea.