Bone grafting is a surgical procedure performed for missing bone due to a variety of causes, including accident and disease, by which the doctor determines various patient needs, such as the site and size of the missing bone, selects the appropriate graft material, and restores the bone’s original shape and physiological function, helping the animal stay healthy.
Necessity of bone grafting
- Periodontal
- Because animal teeth have much longer roots than human teeth, missing teeth leave much deeper voids behind. If exposed roots are left untreated, the animal will chew food using its gums, causing bacterial infection and inflammation, which can lead to more severe diseases. It is crucial to rebuild a healthy gum by filling the voids left by tooth extractions through bone grafting.
- Orthopedic
- On many occasions, bone loss occurs in various regions due to accidents or diseases. If such surgical procedures as TTA and TPLO are necessary for fractures, lost bone, or broken joints caused by accidents, or if a variety of forms of lost bone occurs, such as inflammation and bone cysts, bone grafts suitable for the locations in question can save the lives of animals and keep them healthy.
Autogenic bone graft |
- • Definition : Harvesting of bone from one site of the patient’s body and placing it in another site
- • Advantages : Relatively good healing since it causes no antigen-antibody reaction.
- • Disadvantages : Harvesting bone requires additional surgery and involves pain.
It allows only limited amounts of bone to be harvested and requires a lot of time
and cost.
|
Allogenic bone graft |
- • Definition : Grafting of bone tissue harvested from an animal of the same species
- • Advantages : Excellent healing effect since the bone is harvested from a donor of the same species. Relatively ufficient amounts of bone graft material available compared with autogenic bone grafting.
It’s possible to reduce time and costs without requiring additional surgery for harvesting bone. Allows for various types of bone grafting.
- • Disadvantages : Despite graft products being processed by sterilization, refrigeration, and/or chemical treatment, it is still possible for the animal’s immune system to reject the product or develop an infection.
|
Xenogenic bone graft |
- • Definition : Grafting of bone harvested from an animal of another species that allows for easy harvesting
- • Advantages : Bone graft material is readily available.
- • Disadvantages : Inherited transplantation antigens between animals due to difference of species.
|
Synthetic bone graft |
- • Definition : Grafting of calcium, etc. derived from chemical treatment
- • Advantages : Relatively inexpensive.
- • Disadvantages : Since it is not bio-friendly, it makes it more difficult to expect a good prognosis than bone grafting of the same species.
|
4. Mechanisms of Bone Formation
- Osteogenesis
- The process by which new bone is produced by the direct involvement of osteoblasts and osteoprogenitor necessary for bone formation.
- Osteoinduction
- The process by which bone formation is induced by stimulating the differentiation into osteoblasts of the neighboring stem cells in which there are such growth factors as bone morphogenetic protein (BMP), among the organic components of bone.
- Osteoconduction
- The process by which bone cells produced through osteoinduction and the blood vessels that assist in the growth of those cells are proliferated and serve as a scaffold to create an environment for bone formation.
Characteristics of Allogenic Bone Grafts by Type
- Cortical Bone
- The cortical bone is the outer surface of bone. It is very hard and has high strength and density, which provides the ability to maintain its volume and withstand great loads. These properties allow the bone to serve as a support during the formation of new bone.
- Cancellous Bone
- The cancellous bone makes up the interior of bone and, unlike the cortical bone, has a spongy appearance in the highly porous, three-dimensional form of spicules crisscrossing the bone. Therefore, it serves as a scaffold that helps new bone cells attach, proliferate, and differentiate when new bone is being formed and provides exceptional osteoconductive properties that help create an ideal environment for revascularization
- Demineralized Bone
- The bone consists of approximately 70% inorganic matter and 30% organic matter. The organic matter surrounded by this inorganic matter contains such growth factors as bone morphogenetic proteins (BMP). Through the demineralization process by which inorganic compounds are removed, growth factors such as BMP, which assist in bone repair, are quickly released and promote osteoinduction, contributing to the quality of bone repair.