Pharmacokinetics and Impact of Magnesium Sulfate on Neuromonitoring in Spinal Surgery

What this Trial Is About

Researchers are evaluating how magnesium affects neuromonitoring during complex spinal surgeries. The study focuses on Transcranial Motor Evoked Potentials (TcMEPs), a common tool used to monitor the motor pathways and neural integrity in real time during surgery. Because inhaled anesthetics can interfere with TcMEPs, anesthesiologists typically use intravenous propofol and opioids. Magnesium, an opioid-sparing adjunct, is widely used to reduce pain after spinal surgery, but its impact on TcMEPs is not well understood, with only one case report available so far. Participants will receive a single intravenous dose of magnesium sulfate at 30 mg/kg over 10 minutes during spinal fusion surgery. The anesthetic protocol uses propofol and remifentanil to maintain sedation and avoid interference with TcMEPs. Blood samples will be collected at multiple time points up to 12 hours after dosing to measure plasma magnesium levels and study its pharmacokinetics. The study will use standard neuromonitoring equipment already part of the surgery without adding extra procedures. During the surgery, baseline motor-evoked potentials will be recorded before magnesium administration, followed by continuous neuromonitoring. Researchers will assess how magnesium levels influence TcMEP amplitude, latency, and stimulation voltage. The primary outcomes include magnesium serum levels and pharmacokinetic parameters. Safety and effectiveness of neuromonitoring will be monitored throughout, with data collection continuing for about one year. Participation involves no extension of anesthesia time or additional invasive procedures beyond standard care.

Effect of Magnesium on Neuromonitoring