Surgical treatment of the painful motion segment: matching technology with indications.

Methods: Literature review of current bone graft technology and bone graft substitutes used in spinal fusion applications. Objective: We reviewed current bone graft technologies and identified the range of bioactive properties that each possesses, such as osteoconductivity, osteoinductivity, and structural, load-bearing capabilities that can be used to either augment or replace autogenous bone graft in spinal fusions.

Background: Bioactive materials are used in spinal fusion applications to encourage bone formation across an intervertebral motion segment. To be an effective replacement for autogenous bone grafts, a bioactive material must possess the properties of osteoinduction and osteoconduction.

Methods: Literature review.

Results: Platelet gel concentrates deliver nonspecific cytokines that influence local cells at the implantation site. Demineralized bone matrix acts as a bone graft enhancer that excludes fibrous tissue of muscle interposition in a fusion mass and is a mildly osteoinductive material. Bone morphogenetic proteins are an integral part of natural bone formation response. They function as differentiation factors that act on mesenchymal stem cells to induce bone formation.

Conclusions: Patient-derived therapies such as platelet gel concentrates contain cytokines that play a role in bone formation; however, none of them is capable of inducing the entire bone formation cascade. Clinical use of these concentrates could possibly interfere with new bone formation. The use of bone marrow aspiration and concentration techniques has not been convincingly studied in spinal fusions in lower order animal or human clinical studies. Demineralized bone matrix contains small and variable amounts of naturally occurring bone morphogenetic proteins. These products can only function as bone graft extenders. Recombinant bone morphogenetic protein products contain much more highly concentrated and focused amounts of bone morphogenetic proteins, and some have been shown to be clinically effective bone graft replacements.