Effect of Magnesium Sulfate Bolus on Intraoperative Neuromonitoring

This study is investigating whether giving a dose of magnesium sulfate during surgery affects the accuracy of intraoperative neuromonitoring — the real-time tracking of nerve signals used to protect the brain and spinal cord during spine or brain surgery. Magnesium is sometimes used to reduce pain, but its effect on nerve signal monitoring is not fully understood. You may be eligible if... - You are between 18 and 80 years old - You are scheduled for an elective (planned, non-emergency) spine or brain surgery - Nerve signal monitoring (including SSEP and MEP) is planned during your surgery - You are classified as ASA physical status I or II (generally healthy to mildly ill) You may NOT be eligible if... - You have taken magnesium supplements (oral or IV) within the past 2 days - You have known electrolyte imbalances - You have a serious heart condition or heart rhythm disorder - You have severe lung disease - You have significant nerve or muscle disorders (beyond mild arm or neck issues) - You have severe kidney disease - You are pregnant or breastfeeding - Your nerve signals cannot be adequately recorded at baseline Talk to your doctor to see if this trial is right for you.