Ultrasound-Guided Quadratus Lumborum Block Versus Caudal Block for Pain Relief in Children Undergoing Lower Abdominal Surgeries: A Randomized, Double-Blind Comparative Study.

Background: The quadratus lumborum (QL) block, also known as the abdominal truncal block, was developed to provide visceral and somatic analgesia during abdominal procedures. Objectives: This study aimed to assess pain alleviation, the incidence of complications in lower abdominal procedures, and hemodynamic stability between the caudal block and ultrasound-guided QL block. Methods: Fifty-two patients aged 1 to 7 years old from both genders scheduled for unilateral lower abdominal surgery were randomly assigned to 2 study groups: group QL, unilateral QL block (n = 26), and group C, caudal block (n = 26). In group C, children received caudal block. In group QL, an ultrasound-guided QL block was performed. The time to first rescue analgesia was evaluated as a primary outcome. The quality of analgesia was determined using the face, legs, activity, cry, consolability scale (FLACC scale), hemodynamic parameters, and incidence of complications because hemodynamic instability was recorded under ultrasound guidance. Signs of local anesthetics toxicity and the parents' satisfaction were secondary outcomes. Results: The time until the first demand for analgesia postoperatively was statistically longer in group QL compared to group C. A non-significant difference was observed between the 2 groups (P > 0.05) regarding age, weight, gender, duration of surgery, type of surgery, FLACC scale, and hemodynamics (SBP, systolic blood pressure), except at 30 minutes, which was significant in QL block. Also, a non-significant difference was observed in the severity of postoperative pain up to 1 day postoperatively. Group QL showed more satisfaction than group C. No intraoperative complications were detected. Conclusions: Compared to caudal block, QL block produced sustained and adequate analgesia time postoperatively, with higher satisfaction.