![]() ![]() ![]() Mechanical stability is the final requirement for fusion. The newly formed bone ultimately undergoes remodeling according to Wolff’s law, such that reorganization is based on the imposed load. Following differentiation, the osteoblasts produce osteoid matrix, which calcifies into bone. Investigators have hypothesized that an abundant blood supply leads to a higher oxygen tension level, which favors osteoblastic differentiation rather than chondrogenic differentiation. The oxygen tension in the fusion bed also depends on blood supply. These cells can then differentiate into osteoblasts. The factors ultimately attract progenitor cell migration into the fusion bed. Adequate vascularity allows a hematoma, rich with various activated growth factors, to accumulate at the fusion bed. These cells can be provided by cellular grafting to the fusion site, as well as through vascularity to the fusion bed.Ī sufficient vascular supply to the fusion bed is required to complete the various phases of fusion biology. Progenitor cells, which respond to the local environment to produce bone, are the ultimate throughput allowing fusion to occur. A key component of the fusion cascade begins at the cellular level. Without these components, the rate of nonunion is markedly increased. This chapter reviews the key basic science principles, preclinical studies, and clinical studies that guide the surgeon in the appropriate use of biologics in the cervical spine.įor successful spinal fusion to occur, sufficient bone graft, adequate vascularity to the fusion bed, and mechanical stability of the fusion levels are required. Each of these biologics has different characteristics and different degrees of osteoconductivity, osteoinductivity, and ostegenicity. The biologics include demineralized bone matrix (DBM), ceramics, allografts containing mesenchymal stem cells, and growth factors. Historically, allograft and autograft bone have been the mainstays of cervical fusion however, in more recent years, surgeons have begun using a class of bone graft substitutes known as biologics. Surgical fusion of the cervical spine is a common procedure with a myriad of indications. Specifically, the use of recombinant human BMP-2 (rhBMP-2) in the cervical spine remains debated the optimal concentration, carrier system, and associated complications continue to be investigated. Knowledge and understanding of the use of BMP in the cervical continue to evolve BMPs should be used carefully because potential complications remain unknown. The quantity and quality of mesenchymal cells available in allograft containing mesenchymal stem cells are unknown. In single-level anterior cervical diskectomy and fusion, allograft bone is highly effective with similar fusion rates as compared to autograft boneĭBM allows for natural bone morphogenetic proteins (BMPs) to become available to induce bone formation.Ĭeramics are synthetic bone grafts consisting of calcium phosphate biomaterials fused into an osteoconductive structure.īMPs are multifunctional growth factors that belong to the transforming growth factor-β superfamily and have variable osteoinductive properties.ĭBM has no structural support and must be used with a cage or as a graft enhancer.Ĭeramics are brittle and have low impact and fracture resistance. The most common traditional bone graft is autograft, typically harvested from the iliac crest. ![]() Graft materials can also be classified based on their ability to serve as graft extenders, enhancers, or bone graft substitutes. Unlike posterior cervical spine surgery, bone graft requirements for anterior cervical surgery include the ability for the graft structurally to resist axial compression.Įach graft material differs in properties providing a supply of osteogenic cells, an osteoconductive matrix, and an osteoinductive signal. This chapter reviews the key basic science principles, preclinical studies, and clinical studies that guide the surgeon in the appropriate use of biologics in the cervical spine.Ī successful spinal fusion requires sufficient bone graft, adequate vascularity to the fusion bed, and mechanical stability at the fusion level. Biologics in cervical spine surgery include demineralized bone matrix (DBM), ceramics, allografts containing mesenchymal stem cells, and growth factors. ![]()
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