Monitoring spinal-cord injury intraoperatively and attempting prognosis by cortical somatosensory evoked potentials: experimental study.

Abstract

In order to monitor spinal-cord injury intraoperatively and to evaluate prognosis by cortical somatosensory evoked potentials (CSEP), the spinal-cord function of 42 dogs, whose cords were injured by air-sac pressure or various striking trauma, was monitored by CSEP intraoperatively and 1 to 3 months postoperatively. Although amplitude declined by 100 percent, compared with preoperative readings, spinal-cord injury by air-sac pressure had no lasting effects. If the pressure was removed in a timely fashion, the function of the spinal cord recovered after 1 to 3 months postoperatively. As for the effect of various striking traumas, safe limits, according to intraoperative CSEP monitoring, were that the prolonged P1 wave latency was less than 1.5 times, and that the declining P1-N1 wave amplitude was less than 50 percent. The change in amplitude was quite sensitive and its recovery was earlier than morphologic changes and functional recovery. Results indicated that CSEP monitoring of spinal-cord injury intraoperatively is accurate and reliable and that it can also predict an accurate prognosis for the injured spinal cord in this canine model.