The Circulatory Disturbance of Spinal Cord Injury and Its Response to Local Cooling Therapy

Abstract

Thirty adult dogs were subjected to immobilization of the spinal cord under nembutal anesthesia to produce spinal cord injury of two different degrees of severity by means of an impact of 500 G.cm or more and 300 G.cm or less respectively. In one group of animals an assessment was made of the resultant disturbance of spinal cord circulation at its acute stage while registering the serotonin content of the injured segment of the spinal cord as well as the evoked spinal cord potentials in response to peripheral nerve stimulation. The other group underwent local spinal cord cooling (1000 ml/hr.) for a comparison with the nontreated group of the ensuing changes in the circulatory disturbance of the spinal cord. As a result, it was found that the impact on the spinal cord, because of the anatomical constitution of the spinal arteries and veins as well as the specific features of spinal cord circulation, gave rise to rupture of microvessels in the central gray substance along with petechial hemorrhage, which in turn led to elevated serotonin level in the injured area, and that these two phenomena were responsible for the subsequent deterioration of spinal cord circulation with increased central necrosis. It was shown that the local cooling method is effective in ameliorating microcirculation and correcting the metabolic acidosis due to the impact and also in inhibiting the formation of serotonin which acts adversely in these respects.