Pediatrics · Medical Literature
Ultrasound-guided sacral multifidus plane block versus caudal epidural block for postoperative analgesia in pediatric hypospadias surgery: A randomized double-blind controlled trial.
Abstract
Hypospadias repair is associated with moderate to severe postoperative pain in children. Caudal epidural block is traditionally considered the standard regional anesthetic technique for sub-umbilical pediatric surgeries; however, its duration of analgesia and potential adverse effects may be limited. The sacral multifidus plane block (SMPB) is a novel ultrasound-guided fascial plane technique that may provide prolonged analgesia with fewer complications. The aim of this study is to compare the analgesic efficacy and safety of ultrasound-guided sacral multifidus plane block versus caudal epidural block in children undergoing hypospadias repair. This prospective, randomized, double-blind controlled trial included 30 children aged 1-5 years (ASA I-II) scheduled for hypospadias repair. Patients were randomly allocated to receive either SMPB (n = 15) or caudal block (n = 15), using 1 mL/kg of 0.25% bupivacaine. The primary outcome was time to first rescue analgesia. Secondary outcomes included postoperative FLACC pain scores, total rescue analgesic consumption, intraoperative fentanyl requirements, hemodynamic variables, and block-related complications. Pain was assessed for 24 hours postoperatively. Demographic and intraoperative characteristics were comparable between groups. Time to first rescue analgesia was significantly longer in the SMPB group compared with the caudal group (14.8 ± 3.6 vs 9.3 ± 4.2 hours, p = 0.004). FLACC scores were significantly lower in the SMPB group at 6 and 12 hours postoperatively (p = 0.019 and p = 0.001, respectively). Total diclofenac consumption was lower in the SMPB group (0.40 ± 0.20 mg/kg vs 0.70 ± 0.24 mg/kg, p = 0.010). Intraoperative fentanyl requirements and hemodynamic parameters were similar. No major complications were observed. Ultrasound-guided sacral multifidus plane block provides longer-lasting postoperative analgesia and reduces rescue analgesic requirements compared with caudal epidural block in pediatric hypospadias surgery, with a comparable safety profile. SMPB may represent a reliable alternative to caudal block for postoperative pain management in this population.
Clinical relevance
Hypospadias repair is one of the most common pediatric urologic procedures and is associated with moderate-to-severe postoperative pain; optimal regional analgesia remains a clinical priority. While caudal epidural block has long been the standard technique for sub-umbilical surgeries in children, its relatively limited duration of action and potential adverse effects (e.g., motor blockade, urinary retention, risk of dural puncture) necessitate exploration of alternatives. The sacral multifidus plane block (SMPB) is a novel ultrasound-guided fascial plane block that has emerged as a potentially superior option, and this RCT provides the first direct comparative evidence in a pediatric surgical population.
Key findings
1. Time to first rescue analgesia was significantly prolonged in the SMPB group versus the caudal block group (14.8 ± 3.6 hours vs. 9.3 ± 4.2 hours; p = 0.004), representing an approximate 59% extension in analgesic duration. 2. FLACC pain scores were significantly lower in the SMPB group at 6 hours postoperatively (p = 0.019) and at 12 hours postoperatively (p = 0.001), indicating superior pain control during the critical early recovery period. 3. Total postoperative diclofenac consumption was significantly reduced in the SMPB group compared with the caudal group (0.40 ± 0.20 mg/kg vs. 0.70 ± 0.24 mg/kg; p = 0.010), reflecting a clinically meaningful opioid-sparing and NSAID-sparing effect. 4. Intraoperative fentanyl requirements were similar between the two groups, suggesting equivalent intraoperative analgesic efficacy for both techniques. 5. Hemodynamic parameters were comparable between groups throughout the perioperative period, indicating no clinically significant cardiovascular difference between the two blocks. 6. No major block-related complications were observed in either group (n = 15 per arm), supporting a comparable safety profile; however, the small sample size limits definitive conclusions about rare adverse events.
Practice implications
For children aged 1–5 years (ASA I–II) undergoing hypospadias repair, anesthesiologists should consider ultrasound-guided SMPB as a viable and potentially superior alternative to caudal epidural block, particularly when prolonged postoperative analgesia beyond the standard 6–10-hour caudal window is desirable. Both techniques utilized 1 mL/kg of 0.25% bupivacaine, making SMPB directly substitutable at the same dose and concentration without additional pharmacologic complexity. Given the small sample size (n = 30) of this pilot RCT, clinicians should interpret these findings as hypothesis-generating; larger multicenter trials are warranted before SMPB is adopted as the new standard of care, and practitioners should ensure adequate ultrasound-guided training before transitioning from the more established caudal technique.