Clinical and pathomorphological features of penetrating spinal cord injury model with prolonged persistence of a foreign body in the vertebral canal

Abstract

Background. Penetrating spinal cord injury with a foreign body in the spinal canal is one of the most common spinal cord injuries during wartime; the experimental reproduction of particular elements of complex interaction between a foreign body and the spinal cord is complicated.Objective. To examine clinical and pathomorphological features of the model of this type of spinal cord injury.Materials and methods. Animals: albino male rats (5.5 months, 300 grams, inbred line, the original strain is Wistar); experimental groups: basic (spinal cord injury + immediate homotopical implantation of a fragment of the microporous hydrogel – a foreign body [n=10]); comparison groups (spinal cord injury [n=16], spinal cord injury + immediate homotopical implantation of chemically identical macroporous hydrogel NeuroGel™ [n=20]). Model of injury: left-side spinal cord hemisection at ТXI level; monitoring the function of hind legs — the BBB scale; pathomorphological study: conventional histological techniques, transmission electronic microscopy.Results. Compression of the spinal cord by biologically compatible foreign body significantly worsens the course of the regeneration process; during the first 8 weeks the hind ipsilateral leg function indicator (HI LFI) in animals was the lowest one — (1.30±0.94) points by BBB scale; during the 3rd–4th month HI LFI increases to 2.35±0.95 points by BBB scale, which is likely due to the change in the form of a foreign body and its utilization, decrease of the pressure on the spinal cord. On the 24th week of the follow-up HI LFI was (8.45±0.92) points (in NeuroGelTM group) compared with (2.35±0.95) points by BBB scale (in the group with a foreign body). During the experiment a foreign body, unlike the fragments of the NeuroGelTM, was not integrated into the tissue of the spinal cord, was surrounded by a thick fibrous capsule, hardly infiltrated by tissue component. Morphological picture in the contra-lateral part of the spinal cord at the level of injury did not change.Conclusion. The model satisfactorily a mechanical component of a foreign body effect on the spinal cord tissue, presents the picture of post-traumatic syndrome of spasticity; reducing the spinal cord compression even at the late period of injury significantly improves the regeneration process.