Active_comparator: Quadratus lumborum block

After induction of anesthesia and securement of appropriate airway device, the patient will be placed in position for the QL block. Using ultrasound guidance, the pediatric anesthesiology attending will perform unilateral QL block on the side of the anterior iliac bone graft harvest. The dose will be 0.2% ropivacaine, 1 mL per kilogram to a max of 20 mL with an additive of dexamethasone 4 mg. Ultrasonography will be used to identify external oblique, internal oblique, transverse abdominus and quadratus lumborum muscles. A 50 mm-150 mm block needle will be advanced under ultrasound guidance. Ropivacaine will be injected slowly with frequent aspiration to rule out incorrect needle placement. The anesthetic is deposited at the lateral edge of the QL after penetrating the transversus abdominus aponeurosis. Injection will continue to be observed with real time US guidance.

Active_comparator: Local anesthetic infiltration

Patient will undergo induction of anesthesia as deemed appropriate by the attending pediatric anesthesiologist assigned to the case. After induction of anesthesia and securement of appropriate airway device the patient will be turned over to the surgical team to proceed with the operation. The surgeon will proceed with usual injection of local anesthetic as their standard of care; this medication will be charted by the circulating nurse in the Medication Administration Record with local anesthetic type and amount. At the conclusion of the procedure, to maintain the blind, the patient will have a bandage placed where the QL block would have been performed.