Experimental Studies on the Spinal Cord Evoked Potentials in Compression Injury of the Cervical Spinal Cord

The waveform changes and their recovery processes were analyzed by recording the spinal cord evoked potential (SEP) before, during the after graded cervical ventral compression of the cat spinal cord. The SEP was recorded at three levels: compression site, and rostral and caudal sites, in response to single electric shocks at the level of the 8th thoracic vertebra. In the series of graded compression, the most significant changes were observed in the first negative component (Ncl) of the SEP. The magnitude of injury was classified into three groups according to the amplitude decrement of Nc1 component. After release of compression, the SEP showed no recovery in the group whose amplitude decrement was more than 50%.