[Morphological changes in the spinal cord, its meninges and epidural structures in experimental disorders of blood flow in the venae cavae].

The experiment has been carried out on 72 dogs. The dynamics of morphofunctional changes in the spinal cord, its meninges and in the epidural structures have been investigated when the epidural veins of the spinal canal are involved into the collateral blood stream after ligation of the anterior or posterior venae cavae. During the first 24 h after disturbance of the blood stream in the venae cavae, there appears venous stasis in the vessels of the epidural structures, of the spinal cord and its meninges, in neurons and glial elements hypoxia and acidosis appear. However, in connection with reconstruction of the collateralies, compensating the disturbed blood stream, by the end of the first week the phenomena of the venous stasis disappear. As the result of further reconstruction of the collateral bed, the epidural veins of the spinal canal become the main (short) bypass. During 3-5 months after occlusion of the venae cavae not only the ventral epidural veins of the spinal canal are gradually dilating, but the veins of the roots and meninges of the spinal cord, as well. The spinal cord edema develops, its volume increases by 10-18%, neural cells undergo severe morphological changes up to their death. The phenomena of a chronic venous congestion increase in their severity during 3 years, after that compensatory and restorative changes begin prevailing.