Methods: Twenty patients received epidural morphine (3 mg) pre-incision and saline after wound closure (MO1 group), and 20 patients received epidural saline before incision and morphine after wound closure (MO2 group). Postoperatively, all patients received boluses of morphine (1.5 mg) via intravenous patient-controlled analgesia (IV-PCA), and rescue doses of intramuscular diclofenac (75 mg) every 6 hours, as needed.