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.

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Key information

Conditions

Scoliosis Bone Diseases Musculoskeletal Diseases Spinal Curvatures Spinal Diseases

Age range

12 year–18 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

The Hospital for Sick Children

Toronto, Ontario, M5G 1X8, Canada

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Magnesium

Drug

Magnesium will be administered intravenously at a dose of 50 mg/kg bolus followed by an infusion of 10 mg/kg/hr.

Primary outcomes

Somatosensory and motor evoked potentials

Time frame: Baseline

Cortical SEPs will be measured from Cz-Fpz or Ci-Cc (10-20 system of head measurement) and the amplitudes will be taken from the first positive deflection to first negative deflection (P1-N1) after supramaximal stimulation of the posterior tibial nerves at the medial malleolus. The MEP peak-to-peak amplitudes will be measured from left and right tibialis anterior and abductor hallucis muscles. Stimulation parameters will be varied in order to achieve the maximum amplitude values. Evoked potentials will be measured before and at 10 and 30 minutes after the start of the magnesium infusion.
Somatosensory and motor evoked potentials

Time frame: 10 and 30 minutes after the start of the magnesium infusion

Cortical SEPs will be measured from Cz-Fpz or Ci-Cc (10-20 system of head measurement) and the amplitudes will be taken from the first positive deflection to first negative deflection (P1-N1) after supramaximal stimulation of the posterior tibial nerves at the medial malleolus. The MEP peak-to-peak amplitudes will be measured from left and right tibialis anterior and abductor hallucis muscles. Stimulation parameters will be varied in order to achieve the maximum amplitude values. Evoked potentials will be measured before and at 10 and 30 minutes after the start of the magnesium infusion.

Sponsors and collaborators

Lead sponsor

The Hospital for Sick Children

Other

Registry information

Important dates

Study start: 2010
Primary completion: 2012
Study completion: 2012
First posted: Jun 22, 2010
Registry last updated: Nov 19, 2014

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed