Ultrasound-guided Quadratus Lumborum Block Versus Erector Spinae Plane Block for Postoperative Analgesia in Children Undergoing Elective Open Lower Abdominal Surgeries

A high-frequency linear probe will be used to visualize the structures and a 22G, 80-mm echogenic needle will be inserted to deposit the drug. The probe will be placed above the iliac crest, and Petit's triangle will be identified. The three abdominal muscles (i.e., the external oblique, internal oblique, and transversus abdominus muscles) will be identified and will follow posteriorly until the layers of the Thoracolumbar Fascia (TLF) appeared as a bright hyper-echogenic line. The needle will be inserted in-plane along the posterior edge of the probe in anteromedial direction targeting the plane between the quadratus lumborum and psoas major muscle. After confirming the correct needle tip position and negative aspiration for blood, 0.5 mL/kg of 0.25% bupivacaine will be injected incrementally under real-time ultrasound guidance. The procedure will be repeated on the contralateral side.

The patient will be placed in the prone or lateral decubitus position. The ultrasound probe will be positioned para-sagittally approximately 2-3 cm lateral to the midline at the T10-T12 vertebral level. The T11 transverse process will be identified deep to the erector spinae muscle complex. Using an in-plane caudal-to-cranial approach, a 22-gauge echogenic needle will be advanced until the tip contacts the transverse process. Following confirmation of correct plane by injection of 0.5-1 mL saline creating hydrodissection between the erector spinae and transverse process, 0.5 mL/kg of 0.25% bupivacaine will be injected incrementally. The procedure will be repeated contralaterally \].