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Bone Grafts
November 9, 2015
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November 13, 2015

Bone Graft Substitutes

Demineralized Bone Matrix (DBM) is a product of allograft bone, it has had the inorganic mineral removed, leaving behind the organic collagen components. DBM contains the full array of naturally occurring growth factors that signal host to form new bone. Its osteoinductivity can be attributed to a small concentration of growth factors. It is manufactured in powder, fiber, pellet, gel, putty, and sheet forms. Its advantages include its excellent handling characteristics and lack of donor morbidity. Much like allograft it is meticulously screened and process to prevent disease communication. It is also relatively inexpensive and unlimited in quantity compared to other bone graft substitute.

Ceramics are bone graft substitute. They have the desired properties of being non-immunogenic, unlimited in supply, easily sterilized, and readily stored. It allows bone growth on their surface and then they are reabsorbed by the host body with the patient’s own bone remaining in place. Ceramic-based products do not present a risk for disease transfer. However, ceramics has brittle structure and low tensile strength. Ceramics must be protected from excessive loading forces until a solid fusion has taken place. Earlier generations of ceramics were criticized for their extremely slow resorption times. Also, they may occasionally cause inflammation.

Coral graft substitutes are derived from the exoskeleton of marine corals. The structure of the commonly used coral, Porites, resembles similar to that of cancellous bone and its initial mechanical properties those of bone. It has high content calcium carbonate scaffolds that are shown to be biocompatible, osteoconductive, and biodegradable at variable rates. Coral grafts act as an adequate carrier for growth factors and allow cell attachment, growth, spreading and differentiation. When applied appropriately and when selected to match the resorption rate with the bone formation rate of the implantation site, natural coral exoskeletons have been found to be impressive bone graft substitutes.

Graft composites are new generation bone graft substitute, it consists of other bone graft materials and growth factors to achieve the benefits of a variety of substances. Some combinations may include: collagen/ceramic composite, which closely resembles the composition of natural bone, DBM combined with bone marrow cells, which aid in the growth of new bone, or a collagen/ceramic/autograft composite.

 

Bone Morphogenetic Proteins (BMP) are proteins naturally produced in the body that regulate and promote bone growth and healing. It is an isolated protein that induces cells in our body to form new cartilage and bone. During surgery, the BMP is soaked into and binds with a collagen sponge. The sponge is then designed to reabsorb, or disappear, over time. As the sponge dissolves, the bone morphogenic protein stimulates the cells to produce new bone. The BMP also goes away once it has completed its task of jump starting the normal bone healing process. Since there is no need to harvest bone from the patient’s hip for BMP, recipients were spared donor site pain. Complications from the graft harvest site are also eliminated with the use of bone morphogenic. However, There is little debate or controversy about the effectiveness of BMP to grow bone to achieve spinal fusion.

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