Injectable Calcium Phosphate Cement

Ryan Calouro

Problem Being Solved

• An important aspect of bone tissue repair is that its clinical application is quite diverse.

• Due to this, there is not a specific method or approach that applies to all clinical examples.

• The focus of this technology is applied when a bone grafting procedure is used, or in other words, when the structural damage outweighs the body’s capacity to heal the bone on its own.

• Most patients requiring this technology have experienced great trauma or require reconstructive dental surgery.

Problem Being Solved

• Examples of application include:• Non-union fractures• Craniofacial reconstruction• Segmental defect due to tumor removal• Augmentation of bone- specifically hip

replacement• Damaged articulation sites• Spinal fusion

Bone Grafting• This surgical procedure and the new technology being

studied is very interrelated.• $2.5 billion spent on bone grafting procedures annually

as 2.2 million operations occur worldwide during that timespan

• Grafts are possible because bone tissue has the ability to regenerate completely if there is enough space to grow.

• In most instances the grafting material is replaced completely with a full section of regenerated tissue.

• Missing bone is replaced in one of three ways:• Autograft: bone harvested from one’s own body (iliac crest)• Allograft: cadaveric bone (bone bank)• Synthetically-biocompatible substances

Biological Mechanism

• Four major mechanisms necessary to make bone grafting most effective:

1. Osteoconduction- occurs when the grafting material serves as a scaffold (integrated porous structure) for new bone growth allowing osteoblasts to spread and generate new tissue in the damaged area

2. Osteoinduction- the stimulation of osteoprogenitor cells to differentiate into osteoblasts allowing faster integration of the grafting material. (BMP most studied and effective)

3. Osteopromotion- the enhancement of osteoinduction4. Osteogenesis- occurs when osteoblasts from the grafting material

itself contribute to new bone growth.

It is widely understood that an ideal bone graft includes an osteoconductive matrix, osteogenic cells, and osteoinductive proteins.

Autografts

• Advantages:• Autografting is the only

mechanism that contains all properties naturally

• No immune reaction

• Disadvantages:• Requires additional surgery to

acquire grafting material• Very limited quantity• Increased morbidity

• Infection• Chronic Pain• Cosmetic

Allografts

• Advantages:• Eliminates the morbidity of patient’s donor site • Helps solve supply issue

• Disadvantages:• Immune reaction• Greater risk of infection• Disease transmission• Reduction in osteogenic & osteoinductive properties• Ethical & religious concerns

Injectable Cement

• Advantages:• Biodegradable/Biocompatible• No risk of transfer disease or infection• Non immunogenic• Limitless supply• Eliminates morbidity of patient’s donor

site• Can be used to “fill” large fractures

• Disadvantages:• Not much osteogenic or osteoinductive

property without added growth factors

How does it work?

• Mixture of biocemet and water or other aqueous solution

• Dual-chamber syringe allows for accurate and noninvasive placement while also leaving little residue

• Biocement is composed of several derivations of the compound calcium phosphate

• Calcium phosphate is a naturally occurring compound in bone tissue, giving it osteoinductive characteristics

• Due to these characteristics the development of bone fragment in the surrounding soft tissue area is avoided

How does it work?

• Hard-setting paste provides mechanical strength comparable to traditional bone grafting

• Provides a porous scaffold that resorbs overtime• Osteoclast cells begin recycling the material at the junction

between bone and cement almost immediately• Growth factors and antibiotics can be added to the paste in

order to compliment the natural regeneration process

• After healing, all of the cement is replaced with natural new bone tissue

Limitations

• Can only be used in small operations, primarily spinal fusion

• Cannot be used to fully reconstruct areas of deformation• Doesn’t yet replace the use of implantable screws and

plates, often serves as a compliment• Has received FDA approval, but the recipe for the

calcium phosphate cement is still being studied and perfected.

• Healing times may vary depending on patient

Future Direction

• Perfect recipe to allow for quicker healing times• Develop a more workable substance that can be

used to build bone “mold”• Replace the current use of screws and plates/bone

bank materials in general

References

• "Basic Healthcare - What Is Bone." Basic Healthcare - What Is Bone. N.p., n.d. Web.

• Burger, E. L. "Calcium Phosphates as Bone Graft Extenders." Orthopedics 30.11 (2007): n. pag. Healio.

• Ginebra M.P., Calcium Phosphate Cements as Bone Drug Delivery Systems: A Review. Journal of Controlled Release 113: 102-110, 2006.

• Horstmann W.G., An Injectable Calcium Phosphate Cement as a Bone-Graft Substitute. PubMed, pp. 141-4, 2003.

• Ibrahim, Rashid., Kaveh, Kamran., 2010. Bone Grafting and Bone Graft Substitutes. Journal of Animal and Veterinary Advances, 9(6), pp. 1055-1067.

• Nguyen Ngoc Hung., 2012. Basic Knowledge of Bone Grafting. Bone Grafting, Dr Alessandro Zorzi (Ed.), InTech.

• Vorndran, E. "Ready-to-use Injectable Calcium Phosphate Bone Cement as Drug Carrier." Acta Biomaterialia 9.12 (2013): 9558-567. ScienceDirect. Elsevier. Web.