The Effect of Magnesium Sulfate on Motor and Somatosensory Evoked Potentials in Children Undergoing Scoliosis Surgery
The Effect of Magnesium Sulfate on Motor and Somatosensory Evoked Potentials in Children Undergoing Scoliosis Surgery
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.
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.
Inclusion Criteria:

 -  American Society of Anesthesiologists (ASA) status I or II

 -  Adolescent children aged 12 to 18 years undergoing surgery for idiopathic scoliosis

 Exclusion Criteria:

 -  Magnesium use within the last two weeks, either intravenous or oral supplements

 -  Patients with known electrolyte imbalances or conduction disorders. (Sodium <135 or
 >143 mmol/L OR Potassium < 3.7 or > 5.0 mmol/L if 12 to 15 yrs; Potassium <3.7 or >4.8
 mmol/L if 16 to 18 yrs)

 -  Renal, cardiac or neuromuscular disorders.(Urea < 2.9 or > 7.1 mmol/L OR Creatinine
 >79 µmol/L if < 13 yrs; Creatinine > 98 µmol/L if >= 14 yrs)