Spinal fusion requires the use of bone graft. That bone may be
from the patient's own body (called
autograft), from a cadaver (called allograft),
or from an animal (called
xenograft). Other than bone grafts, there are
materials which promotes spinal fusion. Main examples are bone
morphogenetic proteins (BMPs) and demineralized bone matrix (DBM).
There are three ways the biology of bone works: osteoinduction, osteoconduction and osseointegration. Osteoinduction refers to primitive, undifferentiated and pluripotent cells are somehow stimulated to develop into the bone-forming cell lineage. That cause new bone to form where bone doesn't already exist. Autograft bone and BMPs fall into this category. Osteoconduction refers to the way bone graft material builds a scaffold, the framework for bone to fill inside. An osteoconductive material permits bone growth on its surface or down into pores, channels or pipes. Allografts (cadaver bone), coral, and ceramics are examples of materials which their osteoconductive properties are very good. Osteointegration is the structural and functional connection between growing bone and the surface of a spinal artificial implant. Choice of the material for spinal fusion depends on many factors. Use of autograft remains the gold standard for spinal fusions.
Autograft has all properties of an ideal fusion material, namely; osteoinduction, osteoconduction and osseointegration. However, use of allografts and BMPs have certain advantages. There is less blood loss, shorter surgery time, and no pain or other problems at the graft site.
Below, you will find main categories of materials for spinal fusion.
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