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A conceptual picture of the mandible or lower jaw |
Even in modern medicine the reconstruction of bone defects remains a challenging procedure. Finding a replacement synthetic bone material that will be as effective as a patient's own bone tissue is a quest in which the CSIR has made great strides.
Together with the Medical Research Council's Bone Research Laboratory at WITS University, CSIR researchers are looking at the development of a bioceramic material with attached bone morphogenic proteins (BMPs) for craniofacial applications focusing on larger deficiencies such as those caused by tumour resections.
The CSIR's Lara Kotzè explains: "Currently, the 'gold standard' in bone reconstruction is autogeneous bone filling, where bone is removed from the patient at a healthy site (such as the iliac crest in the hip), and used to reconstruct the bone at the defect site. However, this procedure has major shortcomings such as insufficient availability and additional associated pain caused by the harvesting operation. It often results in more complications at the donor site compared to the implant site."
The most common alternative to using a patient's own bone tissue is to harvest the tissue from a donor. If a suitable donor can be found, the risk of potential transhuman infections with diseases such as HIV, hepatitis and more still exists. In addition to infection there is also the possibility of immunologic rejection, which could in some cases be fatal.
A big need therefore exists to find a replacement synthetic bone material that will be as effective as a patient's own bone tissue, yet without the complications and shortcomings.
"An ideal bone substitute should be osteogenic, where the cells in the bonegraft synthesise new bone at the implantation site; osteoinductive, i.e. new bone is formed through the active recruitment of host stem cells from the surrounding tissue, which then differentiate into bone-forming osteoblasts; osteoconductive, where vascularisation and the formation of new bone takes place in the transplant; and also highly biocompatible," says Kotzè.
The CSIR-developed bioceramic material that has specifically been developed to display the above-mentioned characteristics were recently used in a mandible (lower jaw) reconstruction of a nine year old patient.
"The child suffered a large tumour in his lower jaw and the abnormal cell growth infiltrated and destroyed the surrounding bony tissues. He needed extensive surgical excision to remove the tumour, which resulted in significant jaw bone loss. As a result, he required extensive reconstructive surgery. Especially in children there is not enough bone to harvest from the iliac crest and an alternative to harvesting bone from the hip/iliac crest was sought," she explains.
"Our product aims to negate the need for a second surgery to harvest bone by providing a synthetic material (calcium phosphate bioceramics) in combination with recombinant BMPs that is sterile and can be easily implanted together with the metal implant. Our product should produce rapid bone healing at the affected site."
The operation, says Kotzè, has proven to be successful.
Enquiries: CSIR Communication
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