[Posttraumatic changes in the cranial part of the lumbar spinal cord segment in the unstable spinal column].

In experiment performed in 9 dogs the combined lesions of posterior supporting structures of the lumbar part of the vertebral column and of the spinal cord were modeled by partial laminectomy and left LV segment hemisection, respectively. The material was obtained at 14 days, 1 and 2-3 months following the operation. In longitudinal paraffin sections, stained with hematoxylin-eosin and according to Nissl's, Masson's and van Gieson's methods, as well as in silver nitrate-impregnated sections, the morpho-functional characteristics of the injured spinal cord segment were studied. The total surface area of cavities which were formed as a result of nervous tissue destruction were measured. During 2.5 months of the experiment the total surface area of intraspinal cavities in the injury zone was found to increase more than 4 times. The total surface area of the microcavities adjacent to the injury zone in the region of left lateral cord during this period increased from 10% to 34%, while in the intermediate zone this increase was from 6% to 58%. It is concluded that the condition of spinal instability has a negative influence on the viability of the neural structures in the damaged segment of the spinal cord.