CATEGORIES OF BONE GRAFT
Bone graft selection is critical to the outcome of any bone healing procedure. There are currently over 200 different bone grafts available to surgeons today, each with substantial differences in technology, materials, mechanisms of action, indications, and clinical evidence.
Bone grafts can be categorized based on:
- Composition
- Mechanism of action (MOA)
- Approved indication
- Performance data
Recombinant Proteins
Recombinant proteins are naturally occurring proteins that play an active role in bone formation and maintenance. The human sequence of these proteins can be synthetically manufactured in a consistent, controlled process — commonly referred to as "human recombinant" technology, or recombinant human bone morphogenetic protein (rhBMP).
- Composition: rhBMP
- MOA: Highly osteoinductive and provides a strong signal for bone formation
- Authorization: Health Canada Class IV medical device.
Allograft Bone Graft
There are many different allograft products or forms available for use. Some allograft tissue functions through osteoconduction and mild osteoinduction when demineralized, and include mineralized tissue, demineralized tissue, and allograft tissue plus cells.
These products are also regulated differently based on how they are processed. For example, manipulated tissue based products have a specific designation and are regulated as a medical device and require submission to Health Canada for authorization. Tissue based products that fall into the minimally manipulated category are regulated as CTO (cells, tissues, and organs) and do not require a medical device license issued by Health Canada. They are instead regulated on a CTO Establishment License.
- Composition: Donor bone and tissue
- Demineralized MOA: osteoconductive and osteoinductive.
- Authorization : Health Canada Class 4 medical device
- Composition: Donor bone and tissue
- Mineralized tissue MOA: osteoconductive
- Minimally manipulated Demineralized tissue MOA: osteoconductive & Osteoinductive
- CTO
Synthetic Bone Graft
An osteoconductor, synthetic autograft extender bulks up the supply of available autograft bone.
- Composition: Synthetically produced minerals and ceramics
- MOA: Provides an osteoconductive passive scaffold for bone formation
- Authorization : Health Canada Class III medical device.
Xenograft
Xenograft is bone taken from an animal source and transplanted into the body. It is treated at high temperatures (600 C to 100 C) to eliminate contamination.
- Composition: bovine (cow) bone
- MOA: Osteoconductive
Key Questions to Ask When Categorizing Bone Graft Fusion Material
1. What is bone graft technology’s composition?
- Mineral (synthetic)
- Donor bone and tissue (allograft)
- Recombinant protein (rhBMP)
2. What is the technology’s MOA?
- Osteogenesis: Living cells, such as osteoblasts, that form new bone
- Osteoconduction: Passive scaffold to maintain space and allow for bone formation
- Osteoinduction: Active recruitment and stimulation of stem cells, which differentiate into osteoblasts and form bone
3. How was the technology authorized?
- Health Canada Class III Medical Device
- Health Canada Class IV medical Device
- CTO