Intraoperative stimulation of the spinal cord for prevention of spinal cord injury

There are several spinal cord stimulation methods available for eliciting an MEP. As with any procedure, there are strengths and weaknesses associated with each method that the examiner needs to become familiar with. Because each testing situation is different, a specific elicitation or recording technique may not be appropriate for all surgeries. For example, if tumor removal of the spinal cord is being performed, the examiner may wish to avoid using an EMG in order to eliminate the possibility of patient movement. Therefore, before initiating the use of any method for eliciting an MEP, it is the examiner's responsibility to become thoroughly familiar with the technique under consideration. Regarding the NMEP procedure, we feel very confident with this method for monitoring motor tract function. Although a "true" myogenic MEP is the preferred type of response to record, we believe that this response is too unreliable and insensitive for our use. We also believe that any weaknesses associated with the NMEP are more than offset by its strengths. In conclusion, the results from studies described in this chapter indicate that spinal cord stimulation does elicit an MEP. Based on the testing situation, either a myogenic or NMEP can be recorded and can provide the surgeon with information regarding motor tract function. However, it does not appear that information regarding total spinal cord function can be obtained by using only SEPs. In order to provide the surgeon with this information, an SEP and MEP method must be administered.