Comparison of Post-Operative Analgesia of Caudal Versus Dorsal Penile Nerve Blocks for Pediatric Patients Undergoing Hypospadias Repair

BACKGROUND AND RATIONALE Hypospadias repair remains one of the most common pediatric urological procedures, with thousands of cases performed annually worldwide. Despite continuous refinement of surgical techniques, perioperative pain management in this population poses consistent clinical challenges. Children undergoing hypospadias repair typically experience significant postoperative discomfort due to tissue manipulation, dissection of delicate structures, and exposure of the highly innervated penile shaft. Poorly controlled postoperative pain may lead to increased stress responses, delayed discharge, impaired healing, and difficulties with early postoperative voiding. Because pain expression in young children is complex and often non-verbal, anesthesiologists rely on validated objective scoring systems-such as the FLACC scale-to assess discomfort and guide analgesic therapy.

Regional anesthesia is widely employed as an adjunct to general anesthesia to enhance perioperative analgesia while reducing the need for systemic opioids. Among the most widely used techniques are the caudal epidural block and the dorsal penile nerve block. Each technique has distinct advantages, limitations, and implications for recovery, ambulation, and analgesic duration. Caudal block is traditionally considered the gold standard for infra-umbilical surgeries in pediatrics due to its ease of application, high success rate, and ability to provide profound postoperative analgesia. However, concerns persist regarding delayed motor recovery, urinary retention, and potential adverse hemodynamic effects.

In contrast, the dorsal penile nerve block provides targeted sensory blockade limited to the penile region, minimizing motor involvement and typically allowing earlier mobilization. It is frequently favored in ambulatory settings or when rapid recovery is required. However, its duration of action may be shorter, and there is ongoing debate about whether it can provide analgesic efficacy equivalent to caudal anesthesia following more extensive penile reconstruction, such as hypospadias repair. Given the variation in practice patterns and the lack of high-quality comparative studies in the local setting, this trial was designed to provide a head-to-head comparison of the two regional techniques under standardized anesthetic conditions. The objective was to characterize their intraoperative stability, postoperative pain control, recovery profile, need for rescue analgesia, and safety, enabling clinicians to make informed decisions tailored to patient characteristics, surgical technique, and postoperative care priorities.

STUDY DESIGN OVERVIEW This trial was designed as a prospective, randomized, and comparative clinical study conducted at the Pediatric Surgery Unit of Ain Shams University Hospitals. The study was carried out over a six-month period, following institutional ethical approval, and adhered strictly to the principles of good clinical practice and the Declaration of Helsinki. All participants were recruited consecutively from eligible children scheduled for primary hypospadias repair. A computer-generated randomization sequence was utilized to allocate patients into two equal groups receiving one of two regional anesthesia techniques. All procedures were performed by anesthesiologists with extensive experience in pediatric regional anesthesia, ensuring consistency and proficiency across techniques. A standardized perioperative protocol was applied to all cases to avoid confounding variables. General anesthesia was induced and maintained using identical agents, ventilation strategies, and monitoring parameters. The regional blocks were administered after induction but before surgical incision. Hemodynamic stability, adequacy of analgesia, and possible complications were monitored meticulously throughout the intraoperative and postoperative periods. Data collection continued for the first 24 hours after surgery, with measurements obtained at fixed postoperative intervals. Pain scores, hemodynamic variables, time to ambulation, and need for rescue analgesia were recorded using objective and validated tools. All study staff responsible for postoperative evaluation were blinded to group allocation to minimize assessment bias.

ANESTHETIC MANAGEMENT PROTOCOL A unified anesthetic protocol was implemented for all participants to ensure consistency. Upon arrival in the operating room, each child underwent inhalational induction using 8% sevoflurane in 100% oxygen. Intravenous access was then secured with an appropriately sized cannula (22-24G). Routine monitoring included electrocardiography, non-invasive blood pressure, oxygen saturation, and end-tidal CO₂. Once anesthetized, participants were intubated without the use of neuromuscular blocking agents to prevent interference with motor-based postoperative assessments.