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

To compare the postoperative analgesic efficacy of ultrasound-guided Quadratus Lumborum Block (anterior approach) versus Erector Spinae Plane Block (T10-T12 level), both performed bilaterally with 0.25% bupivacaine (0.5 mL/kg per side), in the first 24 hours postoperatively in children undergoing elective open lower abdominal surgery under general anesthesia.

Inclusion Criteria: * Age: 2 to 7 years. * ASA Physical Status Classification I or II . * Scheduled for elective minor open lower abdominal surgery (bilateral inguinal hernia repair, orchiopexy, circumcision, bilateral hydrocele repair), pyeloplasty and ureteric reimplantation. * Weight between 10 and 25 kg. Exclusion Criteria * Known allergy or hypersensitivity to local anesthetics (amide class). * Contraindications to regional anesthesia: coagulopathy (INR \> 1.5, platelets \< 80,000/mm³), local infection at the injection site, or raised intracranial pressure. * Pre-existing neurological, neuromuscular, or spinal disorders. * Significant hepatic dysfunction (Child-Pugh Class B or C) or severe renal impairment (eGFR \< 30 mL/min/1.73 m²). * Previous abdominal or retroperitoneal surgery which likely to distort fascial planes at the injection site. * Emergency or redo surgical procedures. * Inability to assess postoperative pain due to pre-existing developmental or cognitive impairment preventing validated pain scale use. * Intraoperative conversion from open to laparoscopic approach (post-randomization exclusion criterion).