21 may be positioned on an electrified distal end of the cannula or alternatively the entire surface of the electrified cannula may function as the electrode nerve detection is accomplished as follows a stimulus pulse is passed between electrode 21 disposed on the distal end of a probe 20 and patient return electrode 30 in instances where a second probe 22 is also used a stimulus pulse is passed between electrode 23 disposed on the distal end of a probe 22 and patient return electrode 30 in one aspect electrodes 21 or 23 operate as cathodes and patient return electrode 30 is an anode in this case probes 20 and 22 are monopolar preferably when simultaneously using two probes 20 and 22 the stimulus pulse emitted by each of electrodes 21 and 23 is multiplexed so as to distinguish between their signals it should be understood that electrodes 21 and 23 could be replaced by any combination of multiple electrodes operating either in monopolar or bipolar mode in the case where a single probe has multiple electrodes replacing a single electrode such as electrode 21 probe 20 could instead be bi polar with patient return electrode 30 no longer being required subsequent to the emission of a stimulus pulse from either of electrodes 21 or 23 each of myotome locations ml1 through mr3 are monitored to determine if they exhibit an emg response in a preferred aspect as shown in fig3 the intensity of the stimulus pulse passing between electrodes 21 and 30 or between 22 and 30 is preferably varied over time most preferably the current intensity level of the stimulus pulse is incrementally increased step by step in a u201c staircase u201d fashion as.