FR2552659A3 - BONE MATRIX COMPRISING A PLURALITY OF ARTIFICIAL PERFORATIONS AND METHOD OF PREPARATION - Google Patents

Abstract

THE PRESENT INVENTION CONCERNS A BONE MATRIX INCLUDING A PLURALITY OF ARTIFICIAL PERFORATIONS AND A MANUFACTURING PROCESS. THE INVENTION CONSISTS OF FORMING A PLURALITY OF PERFORATIONS 4 IN A BONE OR BONE MATRIX 2 BEFORE IMPLEMENTATION OF THE SAME. THESE PERFORATIONS 4 FACILITATE THE GROWTH OF CELLS AND BLOOD VESSELS AFTER IMPLEMENTATION OF THE BONE 2 MATRIX AND PRODUCE A SIGNIFICANT INCREASE IN THE CAPACITY OF THE BONE 2 MATRIX TO INDUCE BONE FORMATION AND STIMULATE REGENERATION OF BONE. THE INVENTION MAY FOR EXAMPLE BE USED IN THE MEDICAL FIELD.

Description

The present invention relates to a bone matrix comprising

  This matrix can further stimulate and promote the reformation, regeneration and growth of the bone, the tooth and the cartilage material. A process for the preparation of an bone matrix by forming artificial perforations therein, which bone matrix is usable in surgery and dentistry and is similar in structure and composition to natural bone and teeth bone matrix allows orthopedic reformation The method involves forming multiple artificial perforations in the bone or bone matrix prior to its surgical implantation in order to facilitate penetration of cells and blood vessels after i-implantation and to produce a significant increase of the capacity of the material

  implanted to induce bone and cartilage formation and to stimulate bone regeneration.

  As is well known, the bones and teeth are composed of a matrix of organic material consisting of collagenous fibrils and a binding substance of mucopolysaccharides as well as inorganic constituents, especially calcium phosphate in the form of hydroxyapatite. organic matrix is formed of

  filiform molecules arranged in parallel with each other.

  In addition, the tissue is traversed by many capillaries

  microscopic which are oriented in various directions towards these filliform molecules.

  It is known that if the inorganic constituent is partially or completely removed from the bone or

  Tooth, the remaining organic bone material called bone matrix, can be transplanted to bodies of other animals or living humans without substantial detrimental effect.

  As a result, the bone matrix is used in modern medical procedures by virtue of its ability to stimulate and promote the reformation, regeneration and

  growth in bone tissue after transplantation into a body site.

  While the state of the art has admitted the need for methods and materials to stimulate and promote bone reformation, regeneration and growth, no one has described the unique method described in the present invention. In US Pat. No. 3,458,397 there is disclosed a method for producing an osteogenic material from

  animal bone tissue The osteogenic material is injected into an animal for the purpose of inducing bone formation.

  In this process, the bone is fragmented with pepsin in an acid solution and then digested, extracted and precipitated. There is no suggestion in this publication, however, to make artificial perforations in the bone matrix as described. in the present invention. US Pat. No. 4,294,753 discloses a bone protein morphogenetic method for separating proteins from bone tissue. As in the prior publication, this publication requires bone fragmentation and demineralization of the tissue. The demineralized bone tissues are then treated in an aqueous solution with a neutral salt soluble in water and a solubilizing agent. The neutral salt and the solubilizing agent are then separated, and the morphogenetic protein of the bone is hurried Again, no mention is made

  to produce perforations in the substance.

  In U.S. Patent No. 2,621,145, bone compositions are disclosed and include bone particles that are enclosed in a fibrin network. This produces a matrix that is supported on a carrier sheet that is said to be a material. Flexible Plastic The method described in this publication produces a flexible sheet for use in orthopedic surgery and promoting bone regrowth and includes what is called a plurality of complete bristled bone particles embedded in a fibrin network. This publication does not suggest to perforate the bone matrix or fibrin network composition as described in the present invention. US Pat. No. 2,968,593 discloses a process for preparing inorganic bone material by heating animal bone material in a liquid at a temperature of about 80 ° C to about 100 ° C, by drying the material heated bone, substantially degreasing it with a grease remover solvent, and removing the organic matrix from the defatted bone material, for example, by extraction with ethylene diamine to obtain an inorganic matrix. Inorganic bone which is free of any organic material is used for / transplanting from one animal of one species to another species without deleterious effect. However, no suggestion is made in this publication for

  perforate the inorganic bone material thus obtained.

  US Pat. No. 4,172,123 describes a method for degrading / regenerating bone and tooth material. This publication describes a method of manufacturing the bone material which is implanted in an area where it is desired to stimulate the growth of bone. In this publication the bone material is first milled and then the organic matrix of the bone is demineralized. A colloidal solution of the organic matrix is formed and ions are allowed to diffuse into the colloidal solution for the purpose. Although the substance created by this method appears to be used for osteogenesis, this publication does not describe the perforation of this substance as

  described in the present invention.

  It is an object of the invention to provide a novel method of producing artificially perforated bone matrix for promoting bone formation and bone stimulation and regeneration when the perforated bone matrix is implanted during of an orthopedic reconstruction procedure by forming a plurality of artificial perforations in the bone matrix, the artificially perforated bone matrix being readily accepted by the body and corresponding in composition and structure to bones and

natural teeth.

  Another object of the invention is to realize

  such a new and valid artificial bone matrix 40 usable for reconstruction and regeneration.

ration of bones and natural teeth.

  Yet another object of the invention is a novel method of orthopedic reconstruction of the gullet structure using the artificial bone matrix.

  perforated by the novel process of the invention.

  Other objects of the present invention will be

  obvious from the following description.

  In principle, in a process for the preparation of

  bone matrix for surgical implantation, the improvement of the present invention is to add a step of forming a plurality of artificial perforations in the bone matrix prior to surgical implantation thereof by a surgeon.

  Another object of the invention is the artificially perforated bone matrix obtained according to the method of the invention. Yet another embodiment of the invention is a novel method of using the perforated bone matrix artificially to promote the formation and stimulation of bone regeneration by surgically implanting the bone matrix artificially.

  perforated during an orthopedic reconstruction process.

  In order that the invention may be better understood, reference is made to the accompanying Figures: Figure 1 is a side elevational view of a bone matrix having a plurality of artificial perforations; Figure 1a is a side elevational view of another embodiment of formed bone matrix comprising a plurality of artificial perforations; Fig. 1b is a side elevational view of yet another embodiment of formed bone matrix comprising a plurality of artificial perforations of varying size and shape; FIG. 2 is a side elevational view of an artificially perforated bone matrix and a bone having a cavity-like defect, showing how the artificially perforated bone matrix can be used by tamponade or closure. the defect of the bone or cavity; FIG. 3 is a side view of a bone having a defect with a missing portion for an artificially perforated bone matrix was positioned to be ranned to replace the part / bone; and Fig. 4 is a side elevational view showing a bone comprising a fracture, with an artificially perforated bone matrix positioned for

  induce regeneration of the bone and close the fracture.

  Referring to the drawing figures in which like reference symbols designate like elements, the present invention relates to an improvement in the method of preparing bone matrix for use in surgical methods which comprises: adding a step of forming a plurality of artificial perforations in

  this bone, bone material or bone matrix prior to implantation thereof.

  The bone matrix can be produced using any of the methods known in the art

  which may include any combination of the following steps.

  Bone or bone material is taken from any vertebrate. It can then be preserved according to any of the well-known preservation methods. Partial or complete demineralization of the bone or bone material. is carried out to obtain the decalcification by subjecting the bone or bone material to treatment with different acids, chelating agents, electrolysis or any combination of the foregoing procedures. Finally, either before or after demineralization of the bone, bone material or bone matrix, fixation and various physical and chemical methods are performed. The bone material or bone matrix to be prepared, shown in FIG. treated to form a plurality

artificial perforations 4.

  The plurality of perforations 4 can be made in a bone matrix 2 by laser drilling, by puncture or other similar methods. The perforations 4 can have various shapes, and the invention is not limited thereto. , circular, triangular, multi-angular, irregular shapes, in

  cracks or any combinations of these forms.

  The number of perforations 4 in the bone matrix 2 may vary. Multiple perforations, however, produce a substantial increase in the capacity of the bone matrix to induce bone formation or stimulate bone regeneration. appears to be, within specified limits proportional to the number, to the individual desperforation dimension and position in the bone matrix Punctures should be neither dimension nor uniform shape in the bone matrix Figure 1b shows a matrix of bone 6 comprising other shapes having a plurality of perforations 8 of varying shapes and sizes It has been noted, however, that perforations having a maximum cross-sectional area of 0.25 mm to 1.0 mm are optimum size perforations. to induce an increase

  Substantial capacity of the artificially perforated bone matrix to induce bone formation or stimulate bone regeneration.

  Similarly, the perforations should not be uniformly concentrated on a surface area of the bone matrix. In fact, a higher concentration of perforations in a given area of bone matrix will cause greater stimulation of bone growth. This result is particularly useful in orthopedic procedures where the artificially perforated bone matrix abuts against existing bone as in the case of tamponade or when closing any defect or bone cavity or in

  methods for replacing missing parts of bones.

  More specifically, FIG. 2 shows a tamponade situation where a bone matrix 10 comprises a plurality of artificial perforations 12 which are concentrated on the sides 14,16 and 18 of the bone matrix 10 against the bone. the intermediate sides 14 and 16 of the bone matrix, there is a concentration

less perforation 12.

  Similarly, in surgical procedures involving separate bone bridging, shown in Figure 3, a bone matrix 22 is shown comprising a plurality of artflex perforations 24 concentrated on and adjacent to the sides 26 and 28 while at the sides. intermediate 26 and 28 the perforations are less

  Concentrates Bone 30 is also shown.

  Figure 4 shows a portion of a perforated bone matrix 40 used in treatment situations

  having a fracture 42 in the bone 44.

  In such cases or other similar cases, a higher perforatior concentration adjacent to or in the sides of the bone matrix against the existing bone structure will cause greater bone formation, growth, and regeneration in these tissues. More perforated areas of the bone matrix than in other less perforated areas. Thus, when more bone growth or regeneration formation occurs in these areas against the bone structure, the perforated bone matrix will accelerate. faster to the existing bone structure to close the bone defect, cavity or replace the

missing part of a sure way.

  The perforated bone matrix produced as described in the present invention can be used in surgery for the treatment of complicated fractures.

  and old bone fractures that do not heal.

  The perforated bone matrix can also be used

  to dab or close any defect or bone cavity.

  The following specific examples serve to illustrate the

  present invention without however limiting it.

Example 1

  A laboratory control test was performed to examine the induction of bone formation by perforated bone matrix implantation into laboratory test animals. A perforated bone matrix was prepared. according to the present invention and was implanted subcutaneously laterally at the edges of each laboratory rat selected to form a test group. Four days after implantation, a laboratory rat sample from the test group was prepared and samples were taken from the implantation site. On microscopic examination it was found that within perforations of the implanted bone matrix there was an accumulation of new, non-differentiated cells formed with high phosphatase activity

alkaline in their cytoplasm.

  Seven days after implantation, another sample of laboratory rats from the test group was prepared and samples were taken from the implantation sites. On microscopic examination it was found that there was a small number of chondro Ides cells

  differentiated and fibroblasts among the new non-differentiated cells filling the perforations.

  It has been noted that alkaline phosphatase activity has been increased compared to the previous observation made

at four days.

  Two weeks after implantation, another sample of laboratory rats from the test group was prepared and samples were taken at the implantation sites. On microscopic examination, it was found that some occurred around the edge of the perforations with a replacement of bone matrix material by chondroid cells and osteoblas S The perforations were filled with newly formed bone trabeculae covered with osteoblasis Chondroitoid tissue islands and blood vessels newly formed were distributed in the trabecular bone Also

  the alkaline phosphatase activity in the cells filling the perforations was very high.

  One month after implantation, a sample of laboratory rats from the test group was prepared and samples taken from the implantation site. On microscopic examination it was found that the main portion -9 of the implanted perforated bone matrix had undergone resorption and had been replaced by a new formed trabecular bone in which were scattered 5 tissue islands. trabecular bone formed was not limited to the previously implanted bone matrix, but it was found beyond this

  area and surrounded by a capsule resembling the periosteum.

Example 2

  This trial examined the stimulation of bone regeneration by perforated bone matrix implantation. Various laboratory rabbits were chosen to form a test group. The rabbits each had a cubital bone piece of about 1.5. 2.5 cm removed from the middle of the ulnar bone and a perforated bone matrix fragment prepared according to the method of the present invention was inserted into the defect X-ray examination immediately after the implantation procedure. clearly showed

defect of the bone.

  One week after implantation, X-ray examination of the implantation site still clearly showed the defect in the cubital bone. A rabbit sample from the test group was prepared and samples were taken from the implantation site On microscopic examination it was found that all the perforations of the perforated bone matrix to be implanted were filled with young nondifferentiated cells having a

  high activity of alkaline phosphatase.

  Two weeks after implantation, the examination

  X-ray showed a small amount of mineralization in the area of the perforated bone matrix to be implanted.

  A sample of rabbits from the test group was prepared and samples were taken from the implantation site. Microscopic analysis found that all the perforations were filled with cold cells separated by new trabeculae.

of formed bones.

  One month after implantation, X-ray examination showed that the perforated bone matrix to be implanted had undergone mineralization. A sample of rabbits from the test group was prepared and samples were taken from the test site. Implantation At microscopic examination it was found that the perforated bone matrix to be implanted had a resorption which developed from the established centers around the perforations. It was also found that the implanted bone matrix had been replaced by newly formed trabecular bone that had been connected

  trabecular bone developing at the ends of the bone fragments.

  Two months after implantation, X-ray examination showed that the defect in the cubital bone of laboratory rabbits had been replaced by highly mineralized bone tissue. A final sample of rabbits from the test group was prepared and samples taken at the implantation site At microscopic analysis it was found that the cubital bone defect had now

  been filled with bone undergoing a remodeling.

Example 3

  This test examined the induction of bone formation by the perforated bone matrix comprising perforations of different dimensions. A bone matrix was prepared as in Example 1, according to the method described in the present invention, with perforations. of different diameter: 0.25 mm, 0.35 mm, 0.5 mm, 0.75 mm, 1.0 mm, 1.25 mm, 1.5 mm, and 2.0 mm The perforated bone matrix was implanted by carcinoma into laboratory rats as described in Example 1 At different times after implantation, a sample of laboratory rats from the test group was prepared and samples taken from the implantation sites Microscopic analysis of the implanted bone matrix revealed that the most active method of bone formation was in samples with a perforation diameter of 0.25 to 0.5 mm. samples with perforation diameters from 0.75 to 1.0 mm osteogenic were somewhat less active and in samples with 1.25 to 2.0 mm perforation diameter osteogenesis was even lower than previously observed. EXAMPLE 4 This test examined the induction of bone formation by the perforated bone matrix with different density.

perforations.

  Various groups of tests were carried out each

  comprising a number of laboratory rats.

  Perforated bone matrix was prepared as was

  described here and implanted by the uterine route in each laboratory rat in each respective test group. In the first group of the perforated bone matrix was prepared with 0.25 mm perforations.

  There were 25 perforations per cm 2 The calculated total of the

  Perforated area was 1.23% of the total surface area of the perforated bone matrix. On microscopic analysis, this perforated bone matrix showed high osteogenic activity.

  In the second group of the perforated bone matrix was prepared with 0.35 mm diameter perforations There were approximately 20 perforations per cm 2 The calculated total perforated area was 1.92% of the area. of total area of the perforated bone matrix On microscopic analysis this perforated bone matrix showed

high osteogenic activity.

  In the third group of the bone matrix

  was prepared with perforations of 0.5 mm in diameter.

  There were approximately 16 perforations per cm 2 The calculated total perforated area was 3.14% of the surface area

  Total Perforated Bone Matrix Under microscopic analysis this perforated bone matrix demonstrated high osteogenic activity.

  In the fourth test group, bone matrix was prepared with perforations of 0.75 mm in diameter There were approximately 12 perforations per cm The calculated total of perforated area was 5.3% of the area total area of the perforated bone matrix Under microscopic analysis this perforated bone matrix showed osteogenic activity that was somewhat less than that

  in the three previous test groups.

  In the fifth test group, bone matrix 40 was prepared with 1.0 mm diameter perforations. There were approximately 8 perforations per cm 2. The calculated total perforated area was 6.28%. the total surface area of the perforated bone matrix Under microscopic analysis this perforated bone matrix showed osteogenic activity which was also somewhat lower than in the test groups

one to three.

  In the sixth test group, bone matrix was prepared with 1.25 mm perforations of

  diameter There were about six perforations per cm.

  The calculated total perforated area was 7.36% of the total surface area of the perforated bone matrix. Under microscopic analysis, this bone matrix exhibited osteogenic activity which was considerably lower than

  that found in test groups one to five.

  In the seventh test group bone matrix was prepared with 1.5 mm diameter perforations. There were approximately four perforations per cm 2. The calculated total perforated area was 7.06%.

  the total surface area of the perforated bone matrix.

  Under microscopic analysis, this perforated bone matrix showed osteogenic activity which was considerably

  lower than that found in test groups one to five.

  In the eighth test group, bone matrix was prepared with perforations of 2.0 mm.

  diameter There were about three perforations per cm 2.

  The calculated total perforated area was 9.42% of the total surface area of the perforated bone matrix.

  Under microscopic analysis, this bone matrix showed

  very low osteogenic activity.

  The above-described invention is of course susceptible to various variations and modifications within the skill of one of ordinary skill in the art. It should be understood that all such variations and modifications are within the scope of the invention. of the

  Likewise, it must be understood that he

  is provided that all changes and modifications of the examples of the invention described herein for illustrative purposes

  13 are not outside the scope of the invention.

Claims (5)

claims:   A method of preparing bone matrix for surgical implantation, characterized in that said method comprises the step of forming a plurality of artificial perforations in said bone matrix prior to surgical implantation thereof. Process according to Claim 1, characterized   in that these perforations have a regular cross-sectional area.   Process according to Claim 1, characterized in   these perforations have an irregular cross-sectional area.   4 Process according to claim 1, characterized in that these perforations are uniformly distributed on this bone matrix. Process according to claim   what these perforations are concentrated an area of this bone matrix.   1, characterized in at least 6. in 7. in 8. in 9. in 10. this 30 11. this 12.   13. This process according to the fact that the perforations Process according to the that the perforations Process according to the that the perforations Process according to the fact that these perforations Process according to that these perforations itself Process according to that these perforations process according to the that these perforations sor Process according to that these perforations its claim are of claim form are of claim form are of claim form have a claim form   1, characterized triangular 1, characterized polygonal. 1, characterized irregular. 1, characterized in slit. 1 characterized in   it's circular in shape. claim 1, characterized in that it is carried out by drilling. claim 1, characterized in Lt made by puncture. Claim 1, characterized in that performed using a laser.   Bone matrix comprising a plurality of artificial perforations made by carrying out the method according to any one of claims 1 to 13.