Methadone vs Magnesium in Spinal Fusion

Significant pain may occur following posterior spinal fusion despite the use of conventionally accepted techniques including patient controlled analgesia. If detected, a significant reduction in opioid requirements may lead to improved patient satisfaction and decreased opiate side effects. The current study would use a prospective, randomized trial investigating the efficacy of one of 2 regimens as adjuncts to intraoperative anesthesia and postoperative analgesia, along with a third control group. The patients would be randomized to receive remifentanil plus a single intraoperative dose of methadone; remifentanil plus a bolus followed by an infusion of magnesium; or remifentanil alone. In addition, the two medications being studied might make it easier to determine the efficacy of neurophysiologic monitoring including somatosensory evoked potential (SSEP) (amplitude and latency) and motor evoked potential (MEP) (mA) required to elicit the response. The purpose of this study would be to explore the effects of intraoperative methadone vs magnesium on intraoperative anesthetic requirements, postoperative opioid requirements, the efficacy of neurophysiologic monitoring including SSEP and MEP, inspired concentration of desflurane, remifentanil, and the need for intraoperative supplemental agents to control blood pressure.

This arm will receive the current analgesic remifentanil plus and adjunct dose of methadone hydrochloride.

This drug will be used in conjunction with remifentanil as an adjunct analgesic. Remifentanil + methadone (0.1 mg/kg IV over 15 minutes) just after induction of anesthesia

This drug will be given with remifentanil as an adjunct analgesic. Remifentanil + magnesium (50 mg/kg bolus over 30 minutes followed by 10 mg/kg/hour).

To prospectively compare the effects of intra-operative methadone and magnesium on postoperative opioid requirements. Total amount of hydromorphone administered in OR, recovery room (PACU), and on the inpatient ward 24 hours post-operatively.

Inclusion Criteria: Patients older than 12, and younger than 19 years of age undergoing posterior spinal fusion for idiopathic scoliosis American Society of Anesthesiologist (ASA) physical status I or II Parents/Guardian willing and able to authorize informed consent Patients willing and able to authorize assent Exclusion Criteria: Patients presenting with neuromuscular scoliosis Patients deemed at increased risk of adverse reactions due to the presence of pre-existing severe organ system dysfunction, including debilitating lung disease, severe obstructive sleep apnea, severe congenital or acquired heart disease, and/or severe renal impairment Patients who are both being currently treated for a psychological disorder and have a history of hospitalization for said disorder

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