VOL: 102, ISSUE: 40, PAGE NO: 23
Terry Hainsworth, BSc, RGN, is clinical editor, Nursing Times
The Medicines and Healthcare products Regulatory Agency has informed hospitals in England and Wales that bone graft…
The Medicines and Healthcare products Regulatory Agency has informed hospitals in England and Wales that bone graft material, which may include bone obtained illegally without consent, may have been implanted into a small number of UK patients (MHRA, 2006).
The problem was identified last year when a US company was found to have failed in ensuring correct documentation of human tissue donors. The implicated products were recalled but some had already been used in bone grafting procedures in patients in both the US and UK (MHRA, 2006).
What is bone grafting?
Bone is transplanted to aid in healing, strengthening or improving function in procedures such as revision hip replacement and spinal fusion. The graft provides a framework for the new bone to grow on and into (North American Spine Society, 2006).
The process of bone transplantation is not new. It originated in the mid-19th century when the osteogenic properties of bone was first studied. As early as 1881 a Glasgow surgeon described the use of bone grafts in reconstructing a child’s humerus and the first reported use of preserved bone in orthopaedic surgery was in 1942 (Carter, 1999).
The materials used in bone graft techniques today may be transplanted from the patient’s own bones (autograft) or come from a donor (allograft) (North American Spine Society, 2006).
Table 1 (p24) highlights some of the considerations that may influence the choice of bone graft source.
Autogenous bone is generally considered the best graft material, although it may only be available in limited amounts. Bone for autograft can be harvested from the patient in the following sites (North American Spine Society, 2006):
- Iliac crest;
- Proximal tibia;
- Distal radius.
The iliac crest is the most commonly used site but it is also associated with significant morbidity (North American Spine Society, 2006).
Following autograft, patients will have two wound sites, one from the original surgical intervention and another from the donor site. This adds considerably to postoperative pain and discomfort as well as making the surgical procedure longer and more complex (North American Spine Society, 2006).
Autograft bone is regarded as one of the safest to use due to the low risk of disease transmission as well as a better chance of acceptance and effectiveness in the transplant site. This is because it contains the greatest amount of the patient’s own bone-growing cells and proteins. Therefore autograft bone provides a strong framework for the new bone to grow into (North American Spine Society, 2006).
However, limitations in quantities of autograft bone that an individual patient can supply and the demands of a second surgical site have resulted in the use of allograft products.
Bone grafting using allograft bone has become a common procedure. Methods of screening donors, bone preparation and storage have advanced, which has reduced disease transmission (Carter, 1999).
Bone for allograft is mostly obtained from the donation of femoral heads after primary hip replacement. There are strict guidelines for donation including consent and screening. These result in less than half of donations meeting the standards (Fabian et al, 1997).
This has lead to the now common practice of cadaveric donation, where multiple long bones and sections of pelvis are obtained from a cadaveric donor when procuring other transplantable tissue with consent.
It is preferable for cadaveric bone to be retrieved in the operating theatre, as this is a sterile environment. But in some centres bone is harvested in a mortuary and so requires irradiation to sterilise it (Humphries, 2005).
The cadaveric bone is not procured until the end of multiorgan retrieval, after the removal of soft tissue viscera. This can give the donor’s body a macabre appearance and therefore, a calm, dignified environment should be created to preserve the dignity of the deceased donor. The cadaver is then reconstructed with appropriately sized rigid structures to prevent disfigurement (Rees and Haddad, 2003).
Screening and processing
There are normally three stages to ensuring safe bone allograft (Regeneration Technologies, 2006):
- Donor history screening - evaluation of the donor’s medical and social history and assessment and approval for donation by a registered medical practitioner;
- Laboratory testing - to exclude infections such as hepatitis, HIV, syphilis and potential contamination;
- Tissue preparation processing - with various methods of sterilisation such as irradiation.
The MHRA (2006) has confirmed that in the cases where bone graft product was recalled, the testing and processing stages had been completed.
For a variety of moral and religious reasons patients have individual concerns about tissue from other humans being part of a product used in their surgery. Therefore there are legal and ethical issues that should be considered when providing patients with information about procedures utilising products that contain human tissue.
In order to gain informed consent, patients should be given information about the procedure and products that will be used. Now that this issue has come to the attention of the media it is likely that patients will be seeking information about whether their procedure will include the use of human tissue and they will need careful counselling about the reasons for the choice of product, the associated moral and ethical issues and the safety of the product.
It is also likely that patients who have recently undergone these procedures will be seeking advice about their own personal situation. The MHRA advises that the processing and sterilisation that takes place in the production of bone graft material make the health risks from these products negligible. They have written to hospitals to confirm this and to enable clinicians to decide what advice they should give patients. The MHRA is monitoring the situation.