Surgery – Instruments – Orthopedic instrumentation
Patent
1988-08-24
1992-01-28
Green, Randall L.
Surgery
Instruments
Orthopedic instrumentation
606 76, 623 13, 623 16, 428688, A61F 200
Patent
active
050840517
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Technical Field
This invention describes a biocomposite material, which is especially suitable for bone surgical applications.
2. Background Art
It has been found that many ceramic materials have properties, which allow their use as bone graft materials. Ceramic materials (bioceramics), which are tissue compatible and/or which form chemical bonds with bone tissue and/or which promote the growth of bone tissue, are e.g. calcium phosphate: apatites such as hydroxyapatite, HA, Ca.sub.10 (PO.sub.4).sub.6 (OH).sub.2 (R. E. Luedemann et al., Second World Congress on Biomaterials (SWCB), Washington, D.C., 1984, p. 224), trade names such as Durapatite, Calcitite, Alveograf and Permagraft; fluoroapatites; tricalciumphosphates (TCP) (e.g. trade name Synthograft) and dicalciumphosphates (DCP); magnesium calcium phosphates, .beta.-TCMP (A. Ruggeri et al., Europ. Congr. on Biomaterials (ECB), Bologna, Italy, 1986, Abstracts, p. 86); mixtures of HA and TCP (E. Gruendel et al., ECB, Bologna, Italy, 1986, Abstracts, p. 5, p. 32); aluminum oxide ceramics; bioglasses such as SiO.sub.2 -CaO-Na.sub.2 O-P.sub.2 O.sub.5, e.g. Bioglass 45S (structure: SiO.sub.2 45 wt %. CaO 24.5%, Na.sub.2 O 24,5% and P.sub.2 O.sub.5 6%) (C. S. Kucheria et al., SWBC, Washington, D.C., 1984, p. 214) and glass ceramics with apatites, e.g. MgO 4,6 wt %, CaO 44,9%, SiO.sub.2 34,2%, P.sub.2 O.sub.5 16,3% and CaF 0,5% (T. Kokubo et al., SWBC, Washington, D.C., 1984, p. 351) and calcium carbonate (F. Souyris et al., EBC, Bologna, Italy, 1986, Abstracts, p. 41).
The applications of the above ceramic materials as synthetic bone grafts have been studies by different means by using them for example both as porous and dense powder materials and as porous and dense macroscopical samples as bone grafts. Also ceramic powder-polymer composites have been studied in this way (e.g. W. Bonfield et al.. SWBC, Washington, D.C., 1984, p. 77).
Some bioceramics are resorbable like for example tricalciumphosphate (see e.g. P. S. Eggli et al., ECB, Bologna, Italy, 1986, p. 4) and calcium carbonate (F. Souyris et al., ibid, p. 41). The most known of the nonresorbable bioceramics is aluminum oxide. In literature it has been reported that some bioceramics, like hydroxyapatite, are both resorbable (W. Wagner et al., ECB, Bologna, Italy, 1986, Abstracts, p. 48) and nonresorbable (biostable) (e.g. G. Muratori, ibid, p. 64). Resorbable bioceramics dissolve in tissues slowly and/or they are replaced by the minerals of bone tissue. On the other hand, the biostable bioceramics remain in the tissues in an unchanged state, in such a way that the bone tissue grows into contact with the bioceramic.
Porosity of the bioceramic is advantageous, because the bone tissue can grow into the open porosity, if the pores have a suitable size. On the other hand, a problem of macroscopic bioceramic samples and especially of porous samples is their brittleness. It has been tried to compensate for the brittleness of bioceramics by manufacturing of ceramic powders and of biostable or of resorbable polymers composites, where the ceramic powder particles have been bound together by means of a polymer. This has been achieved e.g. by pressing the mixture of bioceramic powder and polymer powder by means of heat and pressure into a composite piece or by binding bioceramic powder by means of a reactive polymer to a composite piece. Such composites are tough when suitable polymers are applied. Composites of a bioceramic powder and resorbable polymer have been described e.g. in Finnish patent application 863573.
The ceramic powder-polymer composites have a disadvantage that the presence of binding polymeric material prevents the direct contact of bioceramic powder particles and bone tissue to each other, and therefore delays and prevents the growth of the bone tissue on the surface of composite material and inside of it, because the bone tissue does not have such an affinity to grow on the surface of biostable or resorbable organic polymers as it has to grow on the surface of bi
REFERENCES:
patent: 4356572 (1982-11-01), Guillemin et al.
patent: 4457028 (1984-07-01), Draenert
patent: 4842604 (1989-06-01), Dorman et al.
Higashi et al., "Polymer-hydroxy-apatite composites for biodegradable bone fillers", Biomaterials 1986, vol. 7, pp. 183-187, May 1986.
Helevirta Pertti
Pellinen Marja
Rokkanen Pentti
Tormala Pertti
Vainionpaa Seppo
Green Randall L.
Prebilic Paul
LandOfFree
Layered surgical biocomposite material does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Layered surgical biocomposite material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Layered surgical biocomposite material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1858168