The current proposed study will compare the efficacy of a continuous infusion of epidural pethidine through a surgically-placed catheter to PCA pethidine in patients who have undergone a lumbar laminectomy. Both strategies are considered usual practice for this institution. PCA pethidine has been used for postoperative analgesia following a variety of surgeries. Compared to PCA morphine and fentanyl it has been shown to associated with similar patient satisfaction17. Pethidine also caused less vomiting and pruritis than other agents.18