Electrophysiological Monitoring Techniques For Spinal Cord Function In A Canine Model

Electrophysiology recording has been utilized in a wide variety of spinal procedures. Until recently, electrophysiological techniques for assessing a canine model of spinal cord injuries have not been described in detail. The purpose of this study was to describe the technique of evoked potential in the canine species for evaluating spinal cord function. The dogs underwent either vertebrectomy with the spinal cord shortened or laminectomy without spinal cord shortening. The function of the spinal cord was evaluated by electromyography to detect somatosensory evoked potential, transcranial electric motor evoked potential, and spinal cord evoked potential at designated time points. Anesthetics, stimulation site, and stimulus intensity affected motor and somatosensory evoked potentials. Adequate analgesia easily abolished the elicited motor evoked potential. A lower amplitude stimulus (5-10 mA) was adequate to elicit spinal cord evoked potential in dogs and there was no advantage to using higher stimulation intensity. This study provides reference data of evoked potentials for evaluation of the function of the spinal cord. The combination of somatosensory evoked potential and spinal cord evoked potentials in intraoperative neurophysiologic monitoring is a reproducible and reliable modality.