A 65-year-old woman who develops the abrupt onset of lower-extremity weakness due to spinal cord compression is taken to the O.R. for emergency T5 to T8 decompressive laminectomy. Monitoring of motor-evoked potentials (MEPs) is planned. Which of the following is likely to provide the best conditions for monitoring MEPs in this situation?
Whenever the spinal cord is at risk of injury, in all procedures above L1, both the motor and sensory function are commonly monitored due to their segregation to anterior or posterior spinal cord locations. Thus, MEPs will also be performed. Unlike somatosensory evoked potentials, where the response to a peripheral nerve stimulus is measured by waveform response in the cerebral cortex using scalp electrodes, the MEP response, created by an electrical stimulus to the motor cortex, is most often measured by an electromyographic response in the hand, leg, and foot muscles.
Total intravenous anesthesia is advocated in all...
