Motor and somatosensory evoked potentials are continuously monitored in the setting of scoliosis surgery to evaluate the integrity of spinal cord pathways. Detection of neural irritation or injury using motor or somatosensory evoked potentials allows the surgeon to modify technique to reverse the insult and proceed without spinal cord compromise. To facilitate evoked potential monitoring, anesthetic agents that attenuate the evoked responses must be avoided.Several different agents have been studied to try to diminish the acute opioid tolerance and/or hyperalgesia seen with remifentanil.~Two studies investigated the effect of magnesium sulfate on intraoperative remifentanil-induced hyperalgesia. In both studies, post-operative pain scores and opioid consumption were decreased in those patients who received magnesium.~Our aim is to establish that magnesium sulfate does not adversely affect somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) in patients undergoing correction of idiopathic scoliosis. Future clinical trials can then be performed investigating the effect of magnesium sulfate on remifentanil-induced hyperalgesia in the same population.
The primary objective of this study is to determine whether magnesium sulfate has a clinically important effect on the amplitude and latency of somatosensory and motor evoked potentials in patients undergoing surgical correction of idiopathic scoliosis.