Evaluation of Analgesia for Spine Fusion Elective Surgery in Children

Inclusion Criteria: 1. Age 10 - \< 18 years 2. American Society of Anesthesiologists (ASA) Physical Status 1 or 2 3. Undergoing PSF for idiopathic scoliosis 4. Participant or legal guardian can speak and read English or Spanish Exclusion Criteria: 1. Pregnant patients 2. Methadone allergy 3. Preoperative prolonged QTc more than 460 msec (-30 days to 0 day) 4. Subjects undergoing concomitant treatment with known cytochrome P450 inhibitors included in methadone labeling (i.e. macrolides (e.g. erythromycin), azole-antifungal agents (e.g. ketoconazole, voriconazole), protease inhibitors (e.g. ritonavir), fluconazole, SSRIs (e.g. sertraline, fluvoxamine) 5. Preoperative opioid use within 30 days before surgery 6. History of severe sleep apnea, defined as a prior sleep study demonstrating an apnea-hypopnea index (AHI) greater than 10. 7. Significant liver, kidney, neurological disease, developmental delay, or any other co-existing medical condition per discretion of the clinical investigator