Hypospadias surgery in pediatric patients requires effective postoperative analgesia to ensure patient comfort and reduce perioperative stress. Caudal epidural block is widely used for analgesia in pediatric urological procedures; however, alternative regional techniques such as the sacral erector spinae plane (ESP) block have recently gained attention.

This prospective comparative study aims to compare the analgesic efficacy of sacral ESP block and caudal epidural block in pediatric patients undergoing hypospadias surgery. Participants will be allocated to receive either sacral ESP block or caudal epidural block according to the study protocol.

The primary outcome will be postoperative pain scores within the first 24 hours after surgery. Secondary outcomes will include total analgesic consumption, time to first rescue analgesia, and block-related complications.

Hypospadias is one of the most common congenital urogenital anomalies in pediatric patients and typically requires surgical correction in early childhood. Effective postoperative pain management is essential to improve patient comfort, reduce perioperative stress, and prevent complications. Inadequate pain control in pediatric surgical patients has been associated with increased morbidity, prolonged hospital stay, and delayed recovery.

Caudal epidural block is widely used for postoperative analgesia in pediatric urological surgery due to its ease of application and high success rate. However, it has limitations such as relatively short duration of analgesia and potential side effects including motor block, urinary retention, and lower extremity weakness. Therefore, alternative regional anesthesia techniques that may provide longer-lasting analgesia with fewer side effects are of increasing interest.

The erector spinae plane (ESP) block is a relatively novel regional anesthesia technique that provides both somatic and visceral analgesia and can be applied at different spinal levels. The sacral approach to ESP block has recently been described as a potential alternative for lower abdominal and urogenital surgeries. However, evidence regarding its effectiveness in pediatric hypospadias surgery remains limited.

This prospective comparative study aims to compare the analgesic efficacy, postoperative analgesic requirements, and block-related complications of sacral erector spinae plane block and caudal epidural block in pediatric patients undergoing hypospadias repair surgery.

Patients aged between 6 months and 7 years with ASA physical status I-II scheduled for hypospadias repair will be included. Participants will be allocated into either the sacral ESP block group or the caudal epidural block group according to the study protocol.

All patients will receive standardized general anesthesia and monitoring. Regional blocks will be performed under general anesthesia prior to surgery. In the sacral ESP block group, the block will be performed under ultrasound guidance using an in-plane technique, and 0.25% bupivacaine at a dose of 0.5 mL/kg will be administered. In the caudal epidural block group, the block will be performed using a standard technique with 0.25% bupivacaine at a dose of 0.5 mL/kg.

Postoperative pain will be assessed using the FLACC (Face, Legs, Activity, Cry, Consolability) scale at 30 minutes, and at 1, 4, 12, and 24 hours after surgery. Total postoperative analgesic consumption, time to first rescue analgesia, and block-related complications (including motor weakness, nausea and vomiting, hypotension, bradycardia, pruritus, intravascular injection, and bleeding) will be recorded.

Statistical analysis will be performed using appropriate tests according to data distribution, with a significance level set at p < 0.05.

Inclusion Criteria:

1. Male patients aged between 6 months to 7 years
2. Scheduled for hypospadias repair surgery
3. ASA physical status I-II
4. No known allergy to local anesthetic agents
5. No contraindications to peripheral nerve blocks
6. Written informed consent obtained from parents or legal guardians

Exclusion Criteria:

1. Known congenital coagulopathy
2. Known allergy to local anesthetic agents
3. Severe systemic disease (ASA III-IV)
4. Severe organ failure
5. Neurological disorders