Analgesia for Hypospadius Repair in Children: A Comparison of Caudal Bupivacaine and Intravenous Morphine

Background: The present study is a prospective randomized double-blinded study that was designed to evaluate and compare the effectiveness of postoperative pain control and the incidence of complications between caudal block and intravenous morphine in paediatric patients undergoing hypospadius repair. Methods: Sixty patients aged 1-7 years were randomly allocated to two groups of thirty. One group received intravenous morphine 100 microgram/kg before the skin incision and the other had a caudal block with 0.5ml/kg bupivacaine 0.25% before the skin incision. All patients received standardized anaesthesia. Pain was assessed using a 0 - 10 scale at 0, 1, 2, 3, 4, 6, 8 and 24 postoperative hours. The time to the first analgesia, the number of paracetamol doses, the incidence of respiratory depression, vomiting, itching, motor weakness and urine retention were assessed during the first 24 hours. Results: Pain scores were significantly higher in group M compared to group C on admission to the post-anaesthesia care unit and during the following 3 postoperative hours. There was no significant difference in pain scores between the two groups at 4, 6, 8 and 24 hours after surgery. The time to the first analgesia was significantly lower in Group M compared to Group C. The total number of intraoperative fentanyl doses was significantly higher in Group M compared to group C, and there was no significant difference in the number of total paracetamol doses over the 24 postoperative hours between the two groups. None of the sixty patients experienced postoperative respiratory depression, urine retention or motor weakness, but significantly more patients in Group M experienced vomiting and itching compared to Group C. The degree of parent s satisfaction about the quality of postoperative analgesia and the side effects was better in the caudal group compared to the morphine group. Conclusion: We conclude that caudal analgesia is more effective than intravenous morphine (100 microgram/kg) for postoperative pain control during the immediate postoperative period in children undergoing hypospadius surgical repair with a higher incidence of vomiting and itching in the morphine treated patients.