Background: Lower-limb peripheral nerve blocks in pediatrics have gained much more popularity in the last few decades. Our purpose of this study was to compare the postoperative analgesic effects between psoas compartment block (PCB) and caudal block in small children undergoing open hip reduction/osteotomies.

Methods: Forty American Society of Anesthesiologists physical status I-II children aged 1 to 6 years planned to undergo open hip reduction/osteotomies were administered general anesthesia and then randomly assigned to receive 1 of 2 regional anesthetics: caudal block (group C, n = 20) or PCB (group P, n = 20). Ropivacaine 0.25% with epinephrine (5 μg/mL) was used in both blocks. The primary outcome of the study was the total consumption of morphine in the first 24 postoperative hrs. Secondary outcomes included dose of intraoperative fentanyl, occurrence of intraoperative hypotension or bradycardia, postoperative pain scores, time to first morphine analgesia, and occurrence of postoperative vomiting or urine retention.

Results: The cumulative dose of morphine administered in the ward in the first postoperative 24 hrs and the time to first rescue morphine dose were higher in group C than in group P (P < 0.001). There were no differences between the 2 groups regarding intraoperative and postoperative complications except for the incidence of urine retention, which was higher in group C than in group P (P = 0.037).

Conclusions: Use of single-shot PCB is superior to single-shot caudal block regarding length of postoperative analgesia and cumulative dose of morphine in small children undergoing open hip reduction/osteotomies.