Autotransplantation of immobilized stromal bone marrow cells during lumbar spondylosyndesis in an experiment

Abstract

Aim. To assess the ability of immobilized autologous bone marrow stromal cells to provide an effective repair with the formation of a robust bone block in the area of the interbody defect of the spinal motor segment after total removal of the intervertebral disc. Methods. Studied were the effects of autotransplantation of different cell fractions isolated from the bone marrow (mononuclear, stromal cells and stromal stem cells) on the formation of the anterior bone block during interbody spondylosyndesis in an experiment on 24 mongrel dogs of different sexes (mean weight 18.3 kg, the mean diameter of the lumbar vertebral bodies according to radiographic study 18.6 mm). All animals underwent the crest puncture the right wing of the ilium, with aspiration of 10 ml of bone marrow, conducted was a total diskectomy at the level of the bodies of the VII and VIII lumbar vertebras with replacement of the interbody defect with a porous metal cylinder of the Nickel titanium of an appropriate shape and size. All animals were randomly divided into four groups, 6 in each. In the first group the interbody defect was filled with a porous metal cylinder only, in the second group - with the fraction of bone marrow mononuclear cells, in the third - with the fraction of stromal cells, in the fourth - with the fraction of culture-grown stromal cells. Results. In the first (control) group established were the signs of delayed formation of the anterior bone block, formation of the hypertrophic interbody pseudarthrosis. Noted was the formation of coarse fibrous capsule in the zone of «implant-bone» contact, an excess of cartilage tissue, the small size and low proliferative activity of osteoblasts, hypoplasia of the blood vessels. In the second group determined was the forming artificial bone block with paravertebral hyperostosis, radiologically - microdislocation of the implant with protrusion into the body of the adjacent vertebra and partial osteointegration with the porous structure of the fixer in the contact «implant-bone» zone. Bone formation occurred by the type of secondary osteogenesis with an excess of cartilage tissue. In the third and fourth groups formed was a robust artificial bone block, no signs of implant dislocation were observed. Determined was the full osteointegration of the porous structure of the fixer in the contact «implant-bone» zone. The newly formed bone tissue surrounded the implant in a muft-like fashion and grew into its porous structure, grew into the periosteal zone of adjacent vertebral bodies, well adhering with their surface. Conclusion. The proposed method of correction of osteoreparation disorders can be considered as an alternative to osteoplastic operations with the transplantation of massive bone grafts, as well as in conditions of systemic disorders of the ostepoetic function with a critical shortage of endogenous progenitors of bone cells.