Spinal Cord Evoked and Cortical Evoked Potentials Under Experimental Compression and Distraction of Spinal Cord

The purpose of this study is to compare spinal cord evoked potentials （SCEP） and cortical evoked potentials （CEP） under experimental compression and distraction of the spinal cord in cats, to know which could detect earlier the impending spinal cord injury. The compression was performed at L1 level with stepwise increments of 375 μm in 10 cats. The distraction was performed at L 1／2 level with increments of 2 mm in 10cats. SCEP and CEP were recorded at each step. In compression models, SCEP reached to the critical point earlier than CEP in all 10 cats. In distraction models, SCEP and CEP reached the point almost at the same time. These results suggested that SCEP could be more reliable than CEP on recent scoliosis surgery, in which combined force of distraction and compression may be added to the spinal cord during surgical maneuver