How reliable are TcMEPs?
Given the right anesthetic conditions, a large majority of patients will have monitorable TcMEPs. Occasionally, a patient will not have evocable lower extremity or upper extremity TcMEPs. This may be due to technical factors (such as stimulus shunting through a thick scalp) or may be caused by poor spinal cord physiology. Once TcMEPs are obtained, however, the responses are very sensitive to changes in motor tract function.
