|Publication number||US3905047 A|
|Publication date||Sep 16, 1975|
|Filing date||Jun 27, 1973|
|Priority date||Jun 27, 1973|
|Publication number||US 3905047 A, US 3905047A, US-A-3905047, US3905047 A, US3905047A|
|Inventors||Roger A Long|
|Original Assignee||Posta Jr John J|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (141), Classifications (15)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent [1 1 Long [451 Sept. 16, 1975 IMPLANTABLE CERAlVIIC BONE PROSTHESIS  Inventor: Roger A. Long, Escondido, Calif.
 Assignee: John J. Posta, Jr., Northridge, Calif.
 Filed: June 27, 1973  Appl. No.: 373,959
 US. Cl 3/1.9; 128/92 C; 106/395; 106/55; 264/43  Int. Cl. A61F 1/24  Field of Search 3/1, 1.9-1.913; 128/92 C, 92 CA, 92 R, 92 G; 32/10 A; 106/395, 55
 References Cited UNITED STATES PATENTS 3,314,420 4/1967 Smith et al 128/92 C 3,662,405 5/1972 Bortz et al. 3,787,900 l/1974 McGee 3/1 FOREIGN PATENTS OR APPLICATIONS 2,008,010 8/1971 Germany 3/1 Primary Examiner-Ronald L. Frinks Attorney, Agent, or FirmJohn J. Posta, Jr., Esq.
 ABSTRACT The improved bone prosthesis of the invention comprises a unitary body containing an eutectic of metal pyrophosphate and refractory oxide. Preferably, the body also contains discrete particles of refractory oxide bonded together by the eutectic which serves as a matrix bonder. Moreover, the particles are preferably of the same refractory oxide, such as alumina, as is present in the eutectic and are of extended surface area for improved strength. The pyrophosphate preferably is calcium pyrophosphate so that the prosthesis is biodegradable. The prosthesis can be prepared, in accordance with the present method, by forming the eutectic, preferably a pourable mixture of the particles and the molten eutectic, and pouring the mixture into and filling a mold of a bone to be duplicated, solidifying the mold and recovering it from the mold. The surface of the prosthesis can be texturized, as by acid etching it, to increase bond ingrowth and/or tissue attachment when implanted.
10 Claims, 1 Drawing Figure IMPLANTABLE CERAMIC BONE PROSTHESIS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to prostheses and more particularly to implantable bone prostheses and methods of making the same.
2. Description of Prior Art A bone prosthesis is an artificial device to replace a missing bone in the body. For example, a bone may have to be removed surgically because of extensive in jury thereto, e.g., erosion by disease, crushing by mechanical injury, or the bone may be missing due to a congenital defect or as a result of an explosion or the like. An artificial bone or bone portion (prosthesis) can be implanted in the body to restore the function of the affected body portion and to provide the necessary. cosmetic effect.
Various types of bone prostheses have been employed. In most instances, an attempt is made to simulate the appearance, i.e., size and shape of the missing bone or bone portion for cosmetic purposes and also to provide a durable structural support. Metal prostheses have been widely used in the past because of their high strength. However, the metal used must be carefully selected with due regard to the possibility of corrosion of the metal by body fluids and/or a possible foreign body reaction, i.e., rejection of or reaction to the metal by the body because of toxicity or incompatibility thereto.
More recently, ceramic bone prostheses more com patible with the body than metals have been used with some success. However, such prostheses are usually not very durable, being brittleand so are easily chipped and broken. Moreover, they cannot be rapidly or easily fabricated as by melting and casting into exact duplicates of the bone to be replaced, because of very high temperatures required to melt such ceramics. Instead, other procedures must be employed which takes considerable time and raise their cost. For example, the prostheses can be formed by press and sintering techniques, often with grinding and fitting to size required after initial fabrication.
It has been found that a close mechanical fit between a prosthesis replacing all or a portion of a bone and the adjacent living bone portions when the prosthesis is in place is important in order to stimulate ingrowth of living bone to bridge the gap with the prosthesis and bond the prosthesis tightly to the living bone. Such tight mechanical bonding enables the assembly to function at an early date in the manner of the original unimpaired bone. In order to obtain the required fit, the missing bone or bone portion must be exactly duplicated in situ and then made permanent. Continued exposure of the impaired area first for bone duplication and then for prosthesis fitting, normally involves trauma, so that minimizing the exposure time becomes important in many instances. As pointed out above, conventional, standard size ceramic prostheses normally take considerable time to fabricate and do not meet this requirement.
Accordingly, there is a need for a prosthesis which can be made economically, easily and rapidly into the exact duplicate of the bone or bone portion to be replaced and thus reduce exposure time, while providing good body compatibility and high structural strength.
It has also been found that growth of living bone into the prosthesis can be achieved and good mechanical bonding of the prosthesis to adjacent bony parts and to adjacent connecting tissue can be accomplished when the surface porosity of the prosthesis is carefully controlled within certain limits. Metal prostheses normally are smooth and, therefore, are unsuitable from this standpoint without substantial texturizing. Ceramic prosthesis usually also are smooth surfaced and difficult to render porous while retaining their structural integrity.
Certain investigations have been made concerning the possibility of forming ceramic prostheses of material which is resorbable by the body, the prosthesis gradually being replaced by ingrowing bone until the prosthesis is completely or substantially completely substituted by living bone. While such materials can, with some problems, be made porous to stimulate bone ingrowth, they are structually weak and are further weakened during resorption, so that total immobilization of the bony area may be required, even if only minor bone replacement is made, until resorption is complete, a considerable inconvenience. Mechanical working of a structurally weak prosthesis may result in its failure. Moreover, it has been found that movement between the weak prosthesis and adjacent bony parts inhibits the healing process, impairing bone ingrowth.
Accordingly, there is a need for a biodegradable resorbable type of prosthesis which provides improved structural integrity during resorption, which can be made with a surface porosity easily and without weakening the same and which can easily be fabricated to exact dimensions for best initial fit of the part to be replaced.
SUMMARY OF THE INVENTION The improved bone prosthesis of the present inven tion and the novel method of making the same satisfy the foregoing needs. The prosthesis and method are substantially as set forth in the Abstract above. Such prosthesis can be made either permanent or resorbable (biodegradable). Both versions exhibit high structural strength, good impact resistance, controlled surface porosity and compatibility with body fluids, and are capable of economically, rapidly and easily being fabricated by the present method into exact duplicates of the bones and bone portions to be replaced. They stimulate rapid bone ingrowth and can provide a source of material used in formation of living bone. Other advantages are set forth in the following detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS The single FIGURE of the drawings schematically depicts in enlarged cross section one embodiment of a portion of a prosthesis in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT As depicted schematically in cross section in the single FIGURE, a portion of a preferred embodiment of the bone prosthesis of the invention is shown. Thus, prosthesis It) is a unitary ceramic body comprising a matrix 12 of an eutectic within which a plurality of discrete particles I4 of refractory oxide are embedded and bonded together. The eutectic is of metal pyrophosphate and refractory oxide.
The metal pyrophosphate, due to its atomic bonding structure, imparts great strength to the ceramic material. It is preferred that calcium pyrophosphate be utilized as the metal pyrophosphate because it has controlled biodegradability and is completely compatible with the body. Calcium pyrophosphate has the general chemical formula Ca P O with a melting point of l356 Ci 2 C. and a stoichiometric composition of 44.1% CaO and 55.9% P It has a density of 3.09 g./cc. in the beta or low temperature (=1140 C.) form. An inversion occurs on heating or cooling of this material and it has been noted that molten calcium pyrophosphate has a tendency to supercool and then freeze rapidly to the beta form, which is more dense than the alpha form.
Calcium pyrophosphate can be made by established chemical procedures. However, in order to obtain the most pure form for use in body implants and the like, it is preferred to calcine dicalcium phosphate at about 900 C. to calcium pyrophosphate as per the following:
Calcium pyrophosphate can be hydrolyzed slowly to the ortho monomolecular form, the rate being dependent on pH and temperature, increasing with acidity and temperature. Calcium pyrophosphate is biodegradable to the ortho monomolecular form in body fluids, assisted by P-O--P splitting body enzymes, so that calcium and phosphate are supplied to the body sera. In turn, the body sera supply calcium and phosphate back to the implant in the formation of normal body bone tissue as a replacement for the absorbed calcium pyrophosphate. It is believed that the living bone building mineral crystalline apatite is supplied in the body through hydrolysis of a less basic calcium phosphate salt. Moreover, residual phosphate salts are known to nucleate apatite. Current theory indicates that in bone, the apatite crystals are small and comprise only a part of the total mineral present, a second mineral being present in the form of a non-crystalline (amorphous) calcium phosphate. Whatever the exact mechanism for the building of living bone involved, it is believed that the availability of a ready supply of calcium and phosphate adjacent to the replacement site stimulates bone ingrowth and rapid replacement of a biodegradable bone implant. Calcium pyrophosphate serves as such a source of supply.
Magnesium pyrophosphate, sodium pyrophosphate and potassium pyrophosphate can also be used a biodegradable metal pyrophosphates, but are less preferred separately since they do not supply calcium for bone building. These pyrophosphates are slowly soluble in water or acidic media and therefore should only be used with a biodegradable or non-biodegradable metal pyrophosphate which is essentially water insoluble, so as to control the rate of degrading of the prosthesis. Their use in combination with the calcium pyrophosphate assists in controlling the hydrolysis reaction.
In the event that it is desired to make the implant non-biodegradable, then an inert metal pyrophosphate such as manganese pyrophosphate, titanium pyrophosphate, iron pyrophosphate, ziconium pyrophosphate or similar inert pyrophosphate, such as is set forth in US. Pat. No. 3,131,073 issued Apr. 28, 1964, can be employed in the present eutectic.
The refractory oxide component of the eutectic preferably comprises any suitable refractory metal oxide such as alumina, zirconia, titania, magnesia, chromia or the like which is insoluble in water and non-toxic to the body. Of the above, it is preferred to use alumina, since it is very inexpensive, readily available, totally inert and non-biodegradable, and it is known, from long term testing, to be completely non-toxic and compatible with the body and its fluids.
A eutectic of the metal pyrophosphate and refractory oxide is formed by any suitable procedure, such as by blending the pyrophosphate with the refractory oxide, both in fine particulate form, e.g., 200 to 300 mesh, and in the proper proportions. The mixture is then melted.
The proper proportion of ingredients for the eutectic is that which just begins to melt and flow at the processing temperature. This can be determined experimentally by utilizing various pyrophosphate-refractory oxide mixtures, varying the concentration of the refractory oxide from mixture to mixture, compacting each mixture, as by pressing up to 10,000 psi, and then heating the mixtures, observing which of the samples just begins to flow, as by rounding of the corners of the sample at the lowest temperature. The test temperature is then lowered while minor Changes are made in the concentration of refractory oxide in new pressed samples containing the pyrophosphate. The lowest temperature at which corner rounding occurs gives a reliable indication of the proper eutectic composition. Such a procedure is set forth in detail in US. Pat. No. 3,131,073, described above.
In the case of a mixture of, by weight 92.5% manganese pyrophosphate (Mn P O and 7.5% alumina (Al- 0 the eutectic temperature is 1,987 F., well below the melting point of the oxide, 3,720 F. It is a characteristic of the eutectic that it melts well below the melting point of its refractory oxide component, so that it can be used to form at lower temperature high strength ceramics. In the case of an eutectic employing calcium pyrophosphate (87.5% by weight) and alumina (12.5% by weight), the eutectic temperature is about2275 F. Such temperature is sufficiently low to permit melting of the eutectic and casting of the same in high temperature resistant molds such as graphite, ceramic, or the like, while the free particles of refractory oxide, e.g., alumina, are maintained.
The eutectic used in the improved bone prosthesis of the invention is highly desirable since it imparts great strength to the prosthesis, acts as a binder for solid particles of refractory oxide when they are dispersed therein and permits melting and casting of exact bone duplicates at temperatures sufficiently low such that conventional molding materials can be used.
Moreover, of considerable importance is the fact that when free particles of refractory oxide are present in the prosthesis and are of the same refractory oxide as that in the eutectic, no substantial degradation of those particles by the eutectic occurs. In other words, the eutectic represents a saturated solution in which the free refractory oxide particles are not dissolved during processing. Accordingly, the concentration and physical structure of such free particles is preserved in processing, leading to a precise prediction of the prosthesis strength, and the size and arrangement of particles, as well as the biodegradability of the prosthesis.
It will be understood that the free refractory oxide particles can be eliminated from the prosthesis, but it usually is much preferred that they be present, since they increase the strength, reduce the brittleness and decrease the shrinkage of the prosthesis. Accordingly, in the preferred embodiment of the invention, the particles are present.
In order to provide proper melting and total bonding of the free refractory oxide particles together by the eutectic, it is preferred to use an initial concentration of the refractory oxide in the eutectic mixture which is very slightly less than that necessary for complete saturation of the eutectic. Accordingly, when the liquid eutectic is formed and the free particles of the refractory oxide are added, a slight melting or dissolving of the outer surface of the particles occurs, assuring their proper bonding together in and with the binder-matric of the eutectic.
The particles of refractory oxide filler particles bonded together by the eutectic usually are of extended surface area, such as high modulus fibers, flakes, or the like, to improve bending strength or stiffness of the prosthesis. Preferably, the particles are of chemically inert refractory metal oxide, such as alumina, zirconia, titania, magnesia or the like. Most preferably, those particles are of the same refractory oxide as is present in the eutectic. Thus, the novel casting method of the invention is impractical to employ when it is desired to use fibers of lengths in excess of about /8 inch. In such instances, either the press and sinter, hot press technique, or similar fabrication can be used or the fibers can be formed into bundles, placed in a mold and then eutectic can be vacuum cast around them.
The novel prosthesis can be fabricated by any suitable method such as conventional slip casting and cold pressing followed by sintering or hot pressing. However, it is preferred to employ the novel method of the present invention, since precisely shaped and sized prostheses can be made rapidly and economically by the novel method. Such method is, however, limited to specific compositions and particle shapes.
ln forming the novel prosthesis in accordance with the present novel method, the eutectic preferably is rendered molten and, preferably, refractory oxide particles are mixed therewith to form a pourable mixture, which is then cast into a mold and solidified therein, as by cooling, after which the mold is separated therefrom and the finished prosthesis recovered.
The pourable mixture usually contains less than by weight of oxide filler particles, with the minimum filler oxide concentration being only that necessary to make a good casting ceramic.
However, when the cold press, slip cast and sintering or hot press technique is employed, the refractory oxide filler particles may be present in a substantially greater concentration by weight, for example, in excess of that of the eutectic binder-matric. Thus, the filler particles in such instances may be present, for example, in a concentration of between about 20 and about 75 percent, by weight of the prosthesis, the eutectic comprising the remainder.
It will be understood that other substances can be added to the prosthesis for certain purposes, i.e., struc tural supports, such as metal sponge or the like, texturizing or pore-forming agents, eutectic temperaturelowering agents, such as sodium phosphate, etc. Such substances usually are present in minor concentrations. In addition, the prosthesis can be made in several parts, e.g., can be provided with a shell or core of the same or different material.
It will also be understood that since the novel prosthesis of the present invention preferably incorporates at least two distinctive components, that is, the eutectic binder-matric of metal pyrophosphate and refractory oxide, plus the filler of refractory oxide particles, it is readily subject to control of the nature, size and extent of its surface pores. Such pores can facilitate live bone ingrowth and locking to or replacement of the prosthesis, and further facilitate the mechanical attachment of adjacent tissue to the prosthesis.
Surface texturizing of the prosthesis can be accomplished by selectively surface etching or leaching out, as by acid or the like, one of the components of the prosthesis, an advantage over single component ceramics. As shown in the single figure, surface pores 16 are present in prosthesis 10, the size and extent depending on the size and shape of filler particles 14 and the nature of any texturizing treatment applied to exterior of prosthesis 10. The nature of the filler and binder-matrix is such that the biodegradability, if any, of the prosthesis 10, as well as its structural strength, impact resistance, and other factors, can easily be controlled by careful selection of the pyrophosphate(s) and the refractory oxide(s) and their relative concentrations, as well as the size and shape of the filler particles. Accordingly, the prosthesis has far greater flexibility in physical and chemical characteristics than conventional ceramic prostheses. Certain further features of the prosthesis of the present invention and the present method are illustrated in the following specific examples:
EXAMPLE I A missing central portion of a human femur is replaced by a bone prosthesis implanted between the two existing end portions of the femur, with a gap therebetween of not in excess of five thousandths of an inch. The prosthesis almost exactly duplicates the missing portion of the femur and is prepared by the following procedure:
A wax impression is made of the missing central portion of the femur by filling in the gap between the two existing femur portions and checking the impression against the cavity defined by the surrounding leg tissue. The wax impression is then removed, a high temperature resistant ceramic mold is formed there around from a dip slurry from which the slurry liquid medium is then removed. The ceramic cast is baked and the wax is then melted, removed from the mold and the mold is then further hardened by firing.
A pourable mixture of a molten eutectic of calcium pyrophosphate and alumina with added solid particles of alumina is then formed. The eutectic has the composition of about 87.5 percent by weight of calcium pyrophosphate and about 12.5 percent by weight of alumina. The eutectic comprises percent by weight of the eutectic mixture with the alumina particles constituting the remainder.
The pourable mixture while at about 2300 F. is poured into the mold to fill the mold and is then allowed to solidify, after which the mold is released and the prosthesis recovered. The total time for forming the impression, manufacture of the mold, and fabrication of the prosthesis is about 60 minutes. The ceramic prosthesis is then inserted into the femur gap and fits substantially perfectly. The surgical opening is then closed and the femur is immobilized, since the two ends of the femur adjacent the prosthesis will need time to solidly fuse with the prosthesis. The prosthesis is biodegradable, its resorption and replacement by living bone occurring over a time period. The prosthesis is economical, hard, durable, of controlled biodegradability, functions very well, cosmetically and structurally knits tightly with the remainder of the femur and stimulates bone ingrowth and bone replacement.
In a parallel test, the eutectic alone is used (without filler oxide) as the pourable mixture and the results are essentially the same. However, it is noted that the ceramic cast body is slightly more brittle and shrinkage is slightly greater.
In a parallel test, titania is substituted for the alumina in the eutectic and as the filler. The eutectic contains about 14 percent by weight of titania and has a melting point of about 2275 F. Comparable results are obtained, since the major eutectic component is biodegradable, while the titania is not, the relative proportions of each determining the rate of biodegradation. The product is strong, of controlled surface porosity, and easy and rapid to make and use.
In an additional parallel test, calcium pyrophosphate eutectic of the first run is used. It is blended with alumina in a ratio of 40 weight percent eutectic to 60 weight percent alumina, to form a dry mixture. This mixture is then pressed into a body at 10,000 psi, and then fired at about 2300 F. for 30 minutes, resulting in a dense ceramic body which is then ground to the desired size and shape to provide a hard, biodegradable prosthesis.
EXAMPLE II The procedure of Example I is followed, except that a non-biodegradable inert prosthesis is fabricated from a molten eutectic of 92.5 percent by weight of manganese pyrophosphate and 7.5 percent by weight of alumina in which alumina particles in a concentration of about percent by weight of the prosthesis are dispersed. The eutectic has a melting point of about 1987 F. and comprises the remainder of the prosthesis. A hard, high structural strength, high impact resistance, chemically inert prosthesis compatible with the body is provided by the economical and rapid casting and molding procedure of Example I. Total time of obtaining the wax impression, making the mold, casting, cool ing and recovering the prosthesis is only about 60 minutes, so that the procedure permits customized fabrica tion of bony parts for substantially immediate emplacement.
In a second parallel run, an eutectic of 87.5 percent by weight of manganese pyrophosphate and 12.5 percent by weight of titania is melted at 1910 F. and mixed with titania flakes in a weight ratio of about 4:1. The molding and casting procedure of Example I is fol lowed, utilizing a casting temperature of about 1950 to 2000 F followed by solidification and recovery of the desired prosthesis. The prosthesis exhibits the improved properties described above for the aluminamanganese pyrophosphate product, including great strength, impact resistance, durability and total inertness to body fluids.
In a third parallel run, a prosthesis is fabricated using the components of the second run except the filler, titania flakes, are added in a weight percentage of about 80 percent to the eutectic mixture and blended to-' gether in a rubber-lined ball mill. The mixture is then shape pressed into a body at 10,000 psi, and sintered for 30 minutes at above 1910 F. The body when cooled is then ground to the desired size and shape to provide a hard, durable inert prosthesis. The overall processing time is considerably longer than in the first two runs of this Example, nor are the dimensions of the prosthesis as accurate as those of the first two runs, and the cost is higher.
EXAMPLE III Prostheses identical to those of Example I (first and parallel second and third runs) are surface texturized by contacting the prosthesis in each instance with dilute hydrochloric acid at elevated temperature (about F.) for about 3 minutes, until the calcium pyrophosphate eutectic at the surface of the prosthesis has been eroded to an average depth of about 44 microns, thereby increasing the porosity of that surface and facilitating live bone growth and/or other tissue thereinto. Accordingly, secure attachment of the prosthesis to adjacent femur bone portions is accomplished rapidly and full functioning of the femur is restored at an early date.
The preceding Examples clearly establish that the bone prosthesis of the present invention can be controllably biodegradable or made totally inert to body fluids. It is non-toxic, very strong and durable with good to high impact strength and can be made very easily and rapidly by the present method. The prosthesis can be surface texturized to control its porosity and can be formed in an exact size and shape for substitution for a missing bone or bone portion. The type of bones for which the described prosthesis can be substituted is not limited to the bones described herein, but are applicable to any desired bone in the body. Likewise, the prosthesis can be substituted for either part or all of any particular bone in the body. Likewise, the prosthesis can be substituted for either part or all of any particular bone in the body. Constituents of the prosthesis can stimulate bone ingrowth, due to the calcium and phosphate supplied by the prosthesis to the body sera. Other advantages are as set forth in the foregoing.
Various modifications and changes can be made in the present prosthesis and the components and in the present method, its steps, constituents and parameters. All such changes and modifications as are within the scope of the appended claims form part of the present invention.
What is claimed and desired to be secured by Letters Patent is:
1. An improved implantable bone prosthesis, said prosthesis comprising a unitary ceramic body containing a eutectic of metal pyrophosphate and refractory oxide, wherein said body includes discrete particles of refractory oxide bonded together by said eutectic, whereby said eutectic bonds together the discrete particles of refractory oxide in such a manner that no substantial degradation of said discrete particles by the eutectic occurs.
2. The improved bone prothesis of claim 1 wherein said particles are in the form of fibers.
3. The improved bone prosthesis of claim 1 wherein said particles are in the form of flakes.
4. The improved bone prosthesis of claim 1 wherein said refractory oxide comprises refractory metal oxide.
5. The improved bone prosthesis of claim 1 wherein said particles are of the same refractory oxide as that of said eutectic.
phate and alumina and wherein said particles consist essentially of alumina.
10. The improved bone prosthesis of claim 9 wherein said particles are of extended surface area for improved structural strength, and wherein said eutectic is present in a concentration in excess of about percent, by
weight, of said prosthesis.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3314420 *||Oct 23, 1961||Apr 18, 1967||Haeger Potteries Inc||Prosthetic parts and methods of making the same|
|US3662405 *||Mar 12, 1969||May 16, 1972||Iit Res Inst||Reinforced porous ceramic bone prosthesis|
|US3787900 *||Jun 9, 1971||Jan 29, 1974||Univ Iowa Res Found||Artificial bone or tooth prosthesis material|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4113500 *||Jun 2, 1977||Sep 12, 1978||Asahi Kogaku Kogyo Kabushiki Kaisha||Sintered apatite body|
|US4135935 *||Jan 31, 1977||Jan 23, 1979||Ernst Leitz Wetzlar Gmbh||Sintered composite material, a process of making same, and a method of using same|
|US4177524 *||May 10, 1977||Dec 11, 1979||Pfaudler-Werke A.G.||Medical securement element with abrasive grains on thread surface|
|US4178686 *||Jan 6, 1978||Dec 18, 1979||Guido Reiss||Artificial tooth with implantable tooth root|
|US4355428 *||Nov 5, 1979||Oct 26, 1982||S.A. Benoist Girard & Cie||Surgical prosthesis with grainy surface|
|US4366253 *||Aug 11, 1980||Dec 28, 1982||Fuji Photo Film Co., Ltd.||Phosphate glass compositions, and glass-ceramic materials, and methods of making the same|
|US4553272 *||Feb 26, 1981||Nov 19, 1985||University Of Pittsburgh||Regeneration of living tissues by growth of isolated cells in porous implant and product thereof|
|US4769349 *||Dec 3, 1986||Sep 6, 1988||General Electric Company||Ceramic fiber casting|
|US4781721 *||May 19, 1986||Nov 1, 1988||S+G Implants||Bone-graft material and method of manufacture|
|US4793809 *||May 21, 1987||Dec 27, 1988||Myron International, Inc.||Fiber filled dental porcelain|
|US4813965 *||Feb 29, 1988||Mar 21, 1989||Nuclear Metals, Inc.||Brazed porous coating and improved method of joining metal with silver material|
|US5204106 *||Apr 19, 1990||Apr 20, 1993||Fbfc International S.A.||Process for restoring an osseous defect or deficiency by filling with osseous tissue|
|US5217496 *||Sep 30, 1992||Jun 8, 1993||Ab Idea||Implant and method of making it|
|US5658332 *||Jun 30, 1994||Aug 19, 1997||Orthovita, Inc.||Bioactive granules for bone tissue formation|
|US5741253 *||Oct 29, 1992||Apr 21, 1998||Michelson; Gary Karlin||Method for inserting spinal implants|
|US5772661 *||Feb 27, 1995||Jun 30, 1998||Michelson; Gary Karlin||Methods and instrumentation for the surgical correction of human thoracic and lumbar spinal disease from the antero-lateral aspect of the spine|
|US5782832 *||Oct 1, 1996||Jul 21, 1998||Surgical Dynamics, Inc.||Spinal fusion implant and method of insertion thereof|
|US5797909 *||Jun 7, 1995||Aug 25, 1998||Michelson; Gary Karlin||Apparatus for inserting spinal implants|
|US5860973 *||Oct 30, 1996||Jan 19, 1999||Michelson; Gary Karlin||Translateral spinal implant|
|US5885299 *||Mar 14, 1996||Mar 23, 1999||Surgical Dynamics, Inc.||Apparatus and method for implant insertion|
|US5965076 *||Sep 22, 1997||Oct 12, 1999||The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration||Method for fabricating soft tissue implants with microscopic surface roughness|
|US5968098 *||Oct 22, 1996||Oct 19, 1999||Surgical Dynamics, Inc.||Apparatus for fusing adjacent bone structures|
|US6063088 *||Mar 24, 1997||May 16, 2000||United States Surgical Corporation||Method and instrumentation for implant insertion|
|US6096038 *||Jun 7, 1995||Aug 1, 2000||Michelson; Gary Karlin||Apparatus for inserting spinal implants|
|US6102948 *||Aug 20, 1997||Aug 15, 2000||Surgical Dynamics Inc.||Spinal fusion device|
|US6120502 *||May 27, 1994||Sep 19, 2000||Michelson; Gary Karlin||Apparatus and method for the delivery of electrical current for interbody spinal arthrodesis|
|US6123705 *||Oct 1, 1996||Sep 26, 2000||Sdgi Holdings, Inc.||Interbody spinal fusion implants|
|US6123912 *||Jan 19, 1999||Sep 26, 2000||National Science Council||Process for producing alumina material for artificial skeleton with high strength|
|US6149650 *||May 8, 1998||Nov 21, 2000||Michelson; Gary Karlin||Threaded spinal implant|
|US6190414||Oct 31, 1996||Feb 20, 2001||Surgical Dynamics Inc.||Apparatus for fusion of adjacent bone structures|
|US6210412||Jun 7, 1995||Apr 3, 2001||Gary Karlin Michelson||Method for inserting frusto-conical interbody spinal fusion implants|
|US6224595||Apr 20, 1998||May 1, 2001||Sofamor Danek Holdings, Inc.||Method for inserting a spinal implant|
|US6228386||Apr 23, 1999||May 8, 2001||Unicare Biomedical, Inc.||Compositions and methods to repair osseous defects|
|US6241770||Mar 5, 1999||Jun 5, 2001||Gary K. Michelson||Interbody spinal fusion implant having an anatomically conformed trailing end|
|US6264656||May 8, 1998||Jul 24, 2001||Gary Karlin Michelson||Threaded spinal implant|
|US6270498||Jun 7, 1995||Aug 7, 2001||Gary Karlin Michelson||Apparatus for inserting spinal implants|
|US6350283||Apr 19, 2000||Feb 26, 2002||Gary K. Michelson||Bone hemi-lumbar interbody spinal implant having an asymmetrical leading end and method of installation thereof|
|US6482427||Mar 15, 2001||Nov 19, 2002||Unicare Biomedical, Inc.||Compositions and methods for repair of osseous defects and accelerated wound healing|
|US6527810||Dec 21, 2000||Mar 4, 2003||Wright Medical Technology, Inc.||Bone substitutes|
|US6540784 *||Jan 19, 2001||Apr 1, 2003||Board Of Regents, The University Of Texas System||Artificial bone implants|
|US6582432||Feb 2, 2000||Jun 24, 2003||Karlin Technology Inc.||Cap for use with artificial spinal fusion implant|
|US6605089||Sep 23, 1999||Aug 12, 2003||Gary Karlin Michelson||Apparatus and method for the delivery of electrical current for interbody spinal arthrodesis|
|US6635086||May 30, 2001||Oct 21, 2003||Blacksheep Technologies Incorporated||Implant for placement between cervical vertebrae|
|US6666890||Aug 28, 2001||Dec 23, 2003||Gary K. Michelson||Bone hemi-lumbar interbody spinal implant having an asymmetrical leading end and method of installation thereof|
|US6749636||Apr 2, 2002||Jun 15, 2004||Gary K. Michelson||Contoured spinal fusion implants made of bone or a bone composite material|
|US6758849||Aug 18, 2000||Jul 6, 2004||Sdgi Holdings, Inc.||Interbody spinal fusion implants|
|US6770074||Nov 17, 2001||Aug 3, 2004||Gary Karlin Michelson||Apparatus for use in inserting spinal implants|
|US6875213||Feb 21, 2003||Apr 5, 2005||Sdgi Holdings, Inc.||Method of inserting spinal implants with the use of imaging|
|US6890355||Apr 2, 2002||May 10, 2005||Gary K. Michelson||Artificial contoured spinal fusion implants made of a material other than bone|
|US6899734||Mar 23, 2001||May 31, 2005||Howmedica Osteonics Corp.||Modular implant for fusing adjacent bone structure|
|US6923810||Jun 7, 1995||Aug 2, 2005||Gary Karlin Michelson||Frusto-conical interbody spinal fusion implants|
|US6977095||Nov 15, 1999||Dec 20, 2005||Wright Medical Technology Inc.||Process for producing rigid reticulated articles|
|US6989031||Apr 2, 2002||Jan 24, 2006||Sdgi Holdings, Inc.||Hemi-interbody spinal implant manufactured from a major long bone ring or a bone composite|
|US7022137||Dec 16, 2003||Apr 4, 2006||Sdgi Holdings, Inc.||Bone hemi-lumbar interbody spinal fusion implant having an asymmetrical leading end and method of installation thereof|
|US7115128||Oct 15, 2003||Oct 3, 2006||Sdgi Holdings, Inc.||Method for forming through a guard an implantation space in the human spine|
|US7156875||Nov 7, 2003||Jan 2, 2007||Warsaw Orthopedic, Inc.||Arcuate artificial hemi-lumbar interbody spinal fusion implant having an asymmetrical leading end|
|US7207991||Mar 18, 2002||Apr 24, 2007||Warsaw Orthopedic, Inc.||Method for the endoscopic correction of spinal disease|
|US7250550||Oct 22, 2004||Jul 31, 2007||Wright Medical Technology, Inc.||Synthetic bone substitute material|
|US7255698||Aug 11, 2003||Aug 14, 2007||Warsaw Orthopedic, Inc.||Apparatus and method for anterior spinal stabilization|
|US7264622||Oct 24, 2003||Sep 4, 2007||Warsaw Orthopedic, Inc.||System for radial bone displacement|
|US7288093||Nov 8, 2002||Oct 30, 2007||Warsaw Orthopedic, Inc.||Spinal fusion implant having a curved end|
|US7291149||Oct 4, 1999||Nov 6, 2007||Warsaw Orthopedic, Inc.||Method for inserting interbody spinal fusion implants|
|US7303584||Apr 22, 2005||Dec 4, 2007||Howmedica Osteonics Corp.||Modular implant for fusing adjacent bone structure|
|US7326214||Aug 9, 2003||Feb 5, 2008||Warsaw Orthopedic, Inc.||Bone cutting device having a cutting edge with a non-extending center|
|US7387643||Nov 7, 2003||Jun 17, 2008||Warsaw Orthopedic, Inc.||Method for installation of artificial hemi-lumbar interbody spinal fusion implant having an asymmetrical leading end|
|US7399303||Aug 20, 2002||Jul 15, 2008||Warsaw Orthopedic, Inc.||Bone cutting device and method for use thereof|
|US7431722||Jun 6, 2000||Oct 7, 2008||Warsaw Orthopedic, Inc.||Apparatus including a guard member having a passage with a non-circular cross section for providing protected access to the spine|
|US7435262||Jun 15, 2004||Oct 14, 2008||Warsaw Orthopedic, Inc.||Contoured cortical bone implants|
|US7452359||Jun 7, 1995||Nov 18, 2008||Warsaw Orthopedic, Inc.||Apparatus for inserting spinal implants|
|US7455672||Jul 31, 2003||Nov 25, 2008||Gary Karlin Michelson||Method for the delivery of electrical current to promote bone growth between adjacent bone masses|
|US7455692||Mar 24, 2005||Nov 25, 2008||Warsaw Orthopedic, Inc.||Hemi-artificial contoured spinal fusion implants made of a material other than bone|
|US7462195||Apr 19, 2000||Dec 9, 2008||Warsaw Orthopedic, Inc.||Artificial lumbar interbody spinal implant having an asymmetrical leading end|
|US7491205||Jun 7, 1995||Feb 17, 2009||Warsaw Orthopedic, Inc.||Instrumentation for the surgical correction of human thoracic and lumbar spinal disease from the lateral aspect of the spine|
|US7534254||Jun 7, 1995||May 19, 2009||Warsaw Orthopedic, Inc.||Threaded frusto-conical interbody spinal fusion implants|
|US7540882||Mar 24, 2005||Jun 2, 2009||Warsaw Orthopedic, Inc.||Artificial spinal fusion implant with asymmetrical leading end|
|US7569054||Nov 8, 2005||Aug 4, 2009||Warsaw Orthopedic, Inc.||Tubular member having a passage and opposed bone contacting extensions|
|US7608105||Jul 20, 2005||Oct 27, 2009||Howmedica Osteonics Corp.||Methods of inserting conically-shaped fusion cages|
|US7611536||Jan 24, 2006||Nov 3, 2009||Warsaw Orthopedic, Inc.||Hemi-interbody spinal fusion implants manufactured from a major long bone ring|
|US7686805||Jul 1, 2004||Mar 30, 2010||Warsaw Orthopedic, Inc.||Methods for distraction of a disc space|
|US7691148||Mar 19, 2005||Apr 6, 2010||Warsaw Orthopedic, Inc.||Frusto-conical spinal implant|
|US7722619||Apr 25, 2006||May 25, 2010||Warsaw Orthopedic, Inc.||Method of maintaining distraction of a spinal disc space|
|US7740897||Oct 6, 2005||Jun 22, 2010||Wright Medical Technology, Inc.||Process for producing rigid reticulated articles|
|US7754246||Sep 8, 2006||Jul 13, 2010||Wright Medical Technology, Inc.||Composite bone graft substitute cement and articles produced therefrom|
|US7758896 *||Apr 15, 2005||Jul 20, 2010||University Of Massachusetts||Porous calcium phosphate networks for synthetic bone material|
|US7766972||Jul 2, 2007||Aug 3, 2010||Wright Medical Technology, Inc.||Synthetic, malleable bone graft substitute material|
|US7789914||Aug 26, 2004||Sep 7, 2010||Warsaw Orthopedic, Inc.||Implant having arcuate upper and lower bearing surfaces along a longitudinal axis|
|US7828800||May 18, 2009||Nov 9, 2010||Warsaw Orthopedic, Inc.||Threaded frusto-conical interbody spinal fusion implants|
|US7879367 *||Jul 17, 1998||Feb 1, 2011||Alfons Fischer||Metallic implant which is degradable in vivo|
|US7887565||Feb 18, 2006||Feb 15, 2011||Warsaw Orthopedic, Inc.||Apparatus and method for sequential distraction|
|US7914530||Apr 25, 2006||Mar 29, 2011||Warsaw Orthopedic, Inc.||Tissue dilator and method for performing a spinal procedure|
|US7914554||Mar 15, 2002||Mar 29, 2011||Warsaw Orthopedic, Inc.||Spinal implant containing multiple bone growth promoting materials|
|US7935116||Nov 25, 2008||May 3, 2011||Gary Karlin Michelson||Implant for the delivery of electrical current to promote bone growth between adjacent bone masses|
|US7935149||Jun 2, 2009||May 3, 2011||Warsaw Orthopedic, Inc.||Spinal fusion implant with bone screws|
|US7942933||Apr 3, 2010||May 17, 2011||Warsaw Orthopedic, Inc.||Frusto-conical spinal implant|
|US7976566||Mar 25, 2002||Jul 12, 2011||Warsaw Orthopedic, Inc.||Apparatus for insertion into an implantation space|
|US7993347||Jul 27, 2000||Aug 9, 2011||Warsaw Orthopedic, Inc.||Guard for use in performing human interbody spinal surgery|
|US8021430||Sep 7, 2010||Sep 20, 2011||Warsaw Orthopedic, Inc.||Anatomic spinal implant having anatomic bearing surfaces|
|US8025903||Feb 13, 2007||Sep 27, 2011||Wright Medical Technology, Inc.||Composite bone graft substitute cement and articles produced therefrom|
|US8057475||Nov 9, 2010||Nov 15, 2011||Warsaw Orthopedic, Inc.||Threaded interbody spinal fusion implant|
|US8066705||Feb 21, 2003||Nov 29, 2011||Warsaw Orthopedic, Inc.||Instrumentation for the endoscopic correction of spinal disease|
|US8137403||Oct 2, 2009||Mar 20, 2012||Warsaw Orthopedic, Inc.||Hemi-interbody spinal fusion implants manufactured from a major long bone ring|
|US8206387||Apr 21, 2011||Jun 26, 2012||Michelson Gary K||Interbody spinal implant inductively coupled to an external power supply|
|US8226652||Nov 14, 2011||Jul 24, 2012||Warsaw Orthopedic, Inc.||Threaded frusto-conical spinal implants|
|US8251997||Nov 29, 2011||Aug 28, 2012||Warsaw Orthopedic, Inc.||Method for inserting an artificial implant between two adjacent vertebrae along a coronal plane|
|US8292957||Apr 3, 2006||Oct 23, 2012||Warsaw Orthopedic, Inc.||Bone hemi-lumbar arcuate interbody spinal fusion implant having an asymmetrical leading end|
|US8323340||Dec 9, 2008||Dec 4, 2012||Warsaw Orthopedic, Inc.||Artificial hemi-lumbar interbody spinal implant having an asymmetrical leading end|
|US8337559||Jun 1, 2010||Dec 25, 2012||Globus Medical, Inc.||Expandable vertebral prosthesis|
|US8343188||Apr 23, 2012||Jan 1, 2013||Warsaw Orthopedic, Inc.||Device and method for locking a screw with a bendable plate portion|
|US8343220||Feb 3, 2010||Jan 1, 2013||Warsaw Orthopedic, Inc.||Nested interbody spinal fusion implants|
|US8353909||Apr 25, 2006||Jan 15, 2013||Warsaw Orthopedic, Inc.||Surgical instrument for distracting a spinal disc space|
|US8409292||May 17, 2011||Apr 2, 2013||Warsaw Orthopedic, Inc.||Spinal fusion implant|
|US8444696||Sep 19, 2011||May 21, 2013||Warsaw Orthopedic, Inc.||Anatomic spinal implant having anatomic bearing surfaces|
|US8673004||Sep 30, 2003||Mar 18, 2014||Warsaw Orthopedic, Inc.||Method for inserting an interbody spinal fusion implant having an anatomically conformed trailing end|
|US8679118||Jul 23, 2012||Mar 25, 2014||Warsaw Orthopedic, Inc.||Spinal implants|
|US8685464||Jan 18, 2007||Apr 1, 2014||Agnovos Healthcare, Llc||Composite bone graft substitute cement and articles produced therefrom|
|US8685465||Aug 29, 2011||Apr 1, 2014||Agnovos Healthcare, Llc||Composite bone graft substitute cement and articles produced therefrom|
|US8721723||Jan 12, 2009||May 13, 2014||Globus Medical, Inc.||Expandable vertebral prosthesis|
|US8734447||Jun 27, 2000||May 27, 2014||Warsaw Orthopedic, Inc.||Apparatus and method of inserting spinal implants|
|US8758344||Aug 28, 2012||Jun 24, 2014||Warsaw Orthopedic, Inc.||Spinal implant and instruments|
|US8834569||Dec 4, 2012||Sep 16, 2014||Warsaw Orthopedic, Inc.||Artificial hemi-lumbar interbody spinal fusion cage having an asymmetrical leading end|
|US8858638||May 20, 2013||Oct 14, 2014||Warsaw Orthopedic, Inc.||Spinal implant|
|US8882835||Feb 22, 2001||Nov 11, 2014||Warsaw Orthopedic, Inc.||Interbody spinal fusion implant having an anatomically conformed trailing end|
|US8926703||May 3, 2011||Jan 6, 2015||Warsaw Orthopedic, Inc.||Spinal fusion implant with bone screws and a bone screw lock|
|US8940203 *||Apr 6, 2011||Jan 27, 2015||Kaohsiung Medical University||Method for preparing composition comprising porous ceramic with thermo-response hydrogel|
|US9078768||May 20, 2005||Jul 14, 2015||Warsaw Orthopedic, Inc.||Arcuate interbody spinal fusion implant having a reduced width and an anatomically conformed trailing end|
|US20020004060 *||Jul 17, 1998||Jan 10, 2002||Bernd Heublein||Metallic implant which is degradable in vivo|
|US20040078039 *||Oct 15, 2003||Apr 22, 2004||Michelson Gary Karlin||Method for forming through a guard an implantation space in the human spine|
|US20040133277 *||Dec 19, 2003||Jul 8, 2004||Michelson Gary Karlin||Spinal implant for insertion between vertebral bodies|
|US20040172131 *||Dec 16, 2003||Sep 2, 2004||Michelson Gary K.||Bone hemi-lumbar interbody spinal fusion implant having an asymmetrical leading end and method of installation thereof|
|US20040230308 *||Jun 15, 2004||Nov 18, 2004||Michelson Gary K.||Contoured cortical bone implants|
|US20050038512 *||Aug 26, 2004||Feb 17, 2005||Michelson Gary Karlin||Implant having arcuate upper and lower bearing surfaces along a longitudinal axis|
|US20050065518 *||Nov 4, 2004||Mar 24, 2005||Karlin Technology, Inc.||Spinal fusion system including spinal fusion device and additional orthopedic hardware|
|US20050071016 *||Jan 5, 2001||Mar 31, 2005||Gerd Hausdorf||Medical metal implants that can be decomposed by corrosion|
|US20050187628 *||Mar 24, 2005||Aug 25, 2005||Michelson Gary K.||Artificial spinal fusion implant with asymmetrical leading end|
|US20050187629 *||Mar 24, 2005||Aug 25, 2005||Michelson Gary K.||Hemi-artificial contoured spinal fusion implants made of a material other than bone|
|US20050187630 *||Apr 22, 2005||Aug 25, 2005||Howmedica Osteonics Corp.||Modular implant for fusing adjacent bone structure|
|US20050255159 *||Apr 15, 2005||Nov 17, 2005||Robert Hyers||Porous calcium phosphate networks for synthetic bone material|
|US20100009103 *||Mar 16, 2007||Jan 14, 2010||Hi-Lex Corporation||Medical material|
|US20110248417 *||Oct 13, 2011||Kaohsiung Medical University||Method for preparing composition comprising porous ceramic with thermo-response hydrogel|
|DE2620907A1 *||May 12, 1976||Nov 17, 1977||Battelle Institut E V||Verankerung fuer hochbelastete endoprothesen|
|EP0116298A1 *||Jan 12, 1984||Aug 22, 1984||Johannes Friedrich Prof. Dr. Osborn||Ceramic bone-substitute material and process for its production|
|U.S. Classification||623/23.56, 501/153, 606/76, 264/43|
|International Classification||A61F2/00, A61F2/30, A61L27/42, A61F2/02|
|Cooperative Classification||A61F2/30767, A61F2210/0004, A61L27/425, A61F2310/00203, A61F2002/30062|
|European Classification||A61L27/42E, A61F2/30L|