Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis – Bone
Patent
1997-01-21
1998-10-20
Prebilic, Paul B.
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
Bone
606 94, 606100, 604264, A61F 228
Patent
active
058240870
DESCRIPTION:
BRIEF SUMMARY
This application is a national stage 35 USC 371 application of PCT/GB95/00815 filed Apr. 10, 1995.
The present invention relates to a method, apparatus and composition for bone regeneration including the treatment of osteoporosis. Osteoporosis affects an increasing number of an aging population, particularly the female elderly. It is mediated at least in part by genetic defects and a fall in circulating oestrogen levels. Although calcium replacement therapy can have some beneficial effects, the larger doses of calcium involved have other less helpful consequences and accordingly, the prognosis for those with bone demineralisation is not particularly good.
Bone formation in old age is a significant problem since not only does bone regrow more slowly in the elderly, but complications are likely to set in. For this reason, a fracture of for example a femur, tibia, etc, in the elderly is serious and can lead to morbidity.
Currently, no direct means exist to increase bone density of for example, the femur neck, trochanter, etc. There exists, therefore, a need for a facile means of increasing bone density particularly in important skeletal areas without significant surgery.
The invention has its genesis in the discovery that an intraosseous composition may be injected into a desired site, which composition then acts to increase density without rejection problems; being swiftly incorporated into the osseous matrix.
Animal studies, particularly in the rat and rabbit, have shown that hydroxyapatite (HA) is a potent osteoconductive material. When surgically reconstructing the skull, zygoma and mandible, HA has been used as a bone graft substitute acting as scaffolding to support new bone growth. It has also been used to fill cavities after excision of bone cysts, as a graft to restore depressed tibial fractures, in cervical interbody fusion, and as a coating on prostheses. Implanted into canine long bones, HA increases the compressive strength of the cancellous bone and increases the bending strength of cortical bone.
We have now however found that HA may be injected in a liquid form and that there is an advantage of a combining HA, and calcium sulphate (CS) with distilled water. Such a liquid composition sets rapidly, somewhat like Plaster of Paris, and the CS is gradually resorbed in-vivo leaving the porous HA with a large surface area for osteoconduction. CS alone is a known osteoconductive medium being slowly absorbed by an advancing front of new bone and indeed, Najjar, et al. in Oral surgery, Oral medicine, Oral pathology, 1991; 1971(1): 9-15have demonstrated that the additional of CS to HA improved its working properties without adversely affecting its osteointegration and said composite showed a higher rate of bone ingrowth than HA alone.
This indeed has been shown in U.S. Pat. No. 4,619,655 (Hanker) which reveals the use of calcium sulfate with hydroxyl apatite as a repair composition for damaged bone. Further in U.S. Pat. No. 5,147,403, free-flowing calcium sulfate has been described for the conjunction of a prosthesis to host bone.
It has also been shown in the rabbit, that certain proteins, in that case bovine osteogenic factor, are osteoinductive which when added to osteoconductive material, lead to an enhancement of bone ingrowth. (Damien, et al., Journal of Biomedical Materials Research, 1990, 24(6): 369-54.)
Bone is an essential requirement for several different surgical procedures such as spinal fusion, hip arthroplasties, the treatment of some types of fractures and in the management of tumour surgery.
Presently bone is usually obtained from the patient as an autogenous graft. The iliac crest is a common site for harvesting of such bone but there are several problems with this procedure. In the first place, the length of the surgical procedure is significantly increased if bone has to be harvested and indeed damage to the sacroiliac joint can occur thereby. There is a risk of damage to neural and vascular structures in that area and there is a significant risk of long term pain along the scar line
REFERENCES:
patent: 4274163 (1981-06-01), Malcom et al.
patent: 4619655 (1986-10-01), Hanker et al.
patent: 5147403 (1992-09-01), Gitelis
patent: 5306303 (1994-04-01), Lynch
patent: 5431639 (1995-07-01), Shaw
patent: 5702446 (1997-12-01), Schenck et al.
Damien et al., "Investigation of a hydroxyapatite and calcium sulfate composite supplemente with an osteoinductive factro", Journal of Biomedical Materials Research , 1990, 24(6): 369-354.
Najjar et al., "Enhanced osseointegration of hydroxylapatite implant material", Oral Surg Oral Med Oral Pathol , 1991; 71(1); 9-15.
Aspden Richard Malcom
Murali Srimathi Rajagopalan
Porter Richard William
Aberdeen University and Plasma Biotal Limited
Prebilic Paul B.
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