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

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.