According to our adopted protocol, all patients will receive iv infusion of paracetamol 1 g every 6 hours and lornoxicam 8 mg every 12 hours. if patients reached a VAS of ≥ 70 mm despite achieving the maximum preset hourly infusion rates (i.e. 15 ml/hour and 6 ml/hour in the CEA and PCEA groups, respectively), the protocol allows the attending anesthesiologist, who will not be involved in collection of patient data, to unlock the pump temporarily to administer epidural top-up doses of 5 mL of 0.25% bupivacaine plus 2 μg/ml fentanyl every 10 min as required irrespective of the randomization code. If the top-up doses exceeds 25 ml without pain reduction of ≥ 20 mm, an iv bolus injection of 100 mg tramadol will be given.