Comparison of Three Approaches of Electrode Placement to Detect Changes in Motor Evoked Potentials During Spine Surgery

Comparison of Three Approaches of Motor Evoked Potential Recording to Detect a More Reliable Measure to Predict and Prevent Nerve Damage During Spine Surgery

Motor Evoked Potentials are an aspect of intraoperative neuromonitoring, a tool used by neurophysiologists during surgery to prevent irreversible damage to the spinal cord during procedures. This study investigates the utility of three separate quadriceps MEP recording approaches over a total of 40 limbs (20 participants).

The long-term objective of this research is to understand how differing recording techniques may enhance the ability to accurately identify clinically relevant changes in Motor Evoked Potentials (MEPs) during a variety of surgeries where the central motor tracts or lumbar spinal roots are at risk.The specific aims of the proposed research are:

1. Using transcranial magnetic stimulation, evaluate the effects on compound muscle action potentials utilizing intramuscular bipolar recording vs subdermal referential recordings vs subdermal bipolar recordings.
2. Evaluated the variability of amplitude and area between the intramuscular and subdermal recording techniques.

The initial focus will be on recording techniques to obtain stable MEPs in a proximal lower limb muscle, specifically the quadriceps. Continuation research may focus on stimulation techniques to facilitate proximal MEPs and ultimately to improved specificity of MEP changes.

Inclusion Criteria:

• Patients must be ≥18 years of age
• Patients must be undergoing thoracic or lumbar spine surgery where quadriceps MEP recording would be the standard of care
• Patients should have normal preoperative quadriceps strength
• Patients are capable of understanding the informed consent and have signed the informed consent document prior to any study-specific screening procedures or evaluations being performed

Exclusion Criteria:

• Patients with ongoing psychiatric concerns would be excluded.
• Patients who are non-English speakers.