Somatosensory spinal cord evoked potentials in the evaluation of the effect of dexamethasone in experimental spinal cord injury

We studied the effects of high-dose dexamethasone on amplitude and latency values of spinal cord evoked potentials. Thirty-three rabbits were divided into three equal groups. The first group served as the control group, the o thers received high-dose (2.5 mg/kg) dexamenthasone, the second group I hou r prior to and the third group immediately after the induction of a spinal cord trauma in segment T12. The spinal cord evoked potentials were recorded epidurally from T12 segment 5 min before and 5, 30, 60, 90, 120 and 150 mi n after trauma. Pretreatment with dexamethasone (group II) prevented the la tency delay, and later treatment with dexemethasone (group III) prevented t he latency delay partially. Our results suggest that when dexamethasone is given prophylactially it pre vents latency alteration, while treatment with dexamethasone after lesionin g prevents latency alteration partially. From our results we conclude that pretreatment with dexamethasone may involve different mechanisms than were activated in the posttreatment group.