NEUROGENIC MOTOR EVOKED-POTENTIALS - A PROSPECTIVE COMPARISON OF STIMULATION METHODS IN SPINAL DEFORMITY SURGERY

Neurogenic motor evoked potentials (NMEPs) elicited by spinal cord sti mulation via the spinous processes (SP-NMEP) have been widely accepted as a sensitive method of monitoring motor tract function. SP-NMEP req uires additional surgical dissection as well as electrodes within the wound, making the method somewhat inconvenient. A less invasive percut aneous method of spinal cord stimulation (PERC-NMEP) has more recently been described. We prospectively compared the SP-NMEP and PERC-NMEP m ethods in 184 patients undergoing 225 surgical procedures. Although SP -NMEP responses were more readily obtainable than PERC-NMEP, the relia bility of the two methods was not significantly different. Both method s were found to be sensitive to neurologic deficit. The present study suggests that when responses are obtained, the percutaneous method is reliable enough to obviate the spinous process method of monitoring th e motor function of the spinal cord.