Comparison of ultrasound-guided pudendal nerve block and caudal epidural block for postoperative analgesia in children undergoing hypospadias repair: A randomized controlled trial

Objectives: This study aims to determine whether ultrasoundguided pudendal nerve block (USG-PNB) provides improved postoperative analgesia compared to caudal epidural block (CEB) in children undergoing hypospadias repair. Patients and methods: This prospective, randomized, parallel-group, double-blind comparative trial included 40 male children (mean age: 5.92±2.73 years; range, 2 to 12 years) with American Society of Anesthesiologists physical status I or II who were scheduled to undergo hypospadias repair under general anesthesia between March 2023 and January 2024. Participants were randomly allocated (1:1) to either the PNB group, receiving ultrasound-guided PEB (0.3 mL/kg -1 of 0.25% bupivacaine), or the CEB group, receiving CEB (1 mL/kg -1 of 0.25% bupivacaine) following induction of anesthesia. The primary outcome was the proportion of patients requiring additional analgesia within the first 24 h after surgery. Secondary outcomes included postoperative pain scores and total 24-h analgesic consumption. Results: In the first 24 postoperative hours, 80% of children in the PNB group required rescue analgesia compared to 15% in the CEB group (p<0.001). Pain scores were significantly higher in the PNB group at 12 and 18 h but did not differ between groups at 0 h, 30 min, 6 h, or 24 h. Total postoperative analgesic requirement was also significantly greater in the PNB group (p<0.001). Conclusion: In pediatric patients undergoing hypospadias repair, CEB provided longer-lasting postoperative analgesia, reduced analgesic requirements, and greater surgeon satisfaction compared to USG-PNB. Although previous studies have reported favorable outcomes with nerve stimulator-guided PNB, only limited evidence supports improved analgesia with USG-PNB. Since bilateral blockade is required, and the block is technically challenging when performed with ultrasound alone, the success rate may be enhanced by combining ultrasound with nerve stimulator guidance. In our view, USG-PNB should be reserved for high-volume centers with substantial expertise in this technique to ensure reliable analgesia, optimize operating room efficiency, and conserve theatre time.