USE OF SCIATIC NEUROGENIC MOTOR EVOKED-POTENTIALS VERSUS SPINAL POTENTIALS TO PREDICT EARLY-ONSET NEUROLOGIC DEFICITS WHEN INTERVENTION IS STILL POSSIBLE DURING OVERDISTRACTION

Spinal evoked potentials, sciatic neurogenic motor evoked potentials, and somatosensory evoked potentials were recorded before and after ove rdistraction of the spinal cord, and compared with the clinical status of 14 pigs. The sciatic neurogenic motor evoked potential consisted o f two components: fast and slow. The fast component was more sensitive and associated to a greater degree with motor function in wake-up tes ts than the slow component somatosensory evoked potential and spinal e voked potential. Furthermore, the loss of only the fast component in t he initial status allowed the possibility of improvement of motor acti vity in the final wake-up test. The peripheral neurogenic motor evoked potentials recording yielded more information about spinal cord funct ion: motor and sensory. The current study suggests that a peripheral r esponse is a better index to the onset of overdistraction and to the e fficiency of intervention, when the neurologic deficit after overdistr action of the spine is reversible.