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.