JP2001231797A - Modularized artificial bone - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modularized artificial bone which makes it possible to easily obtain shapes and dimensions desired to be complemented, does not exert burden to the living body and may be easily integrated with the osteostructure of the living body. SOLUTION: The artificial bone to be replaced in the defective part of the hard tissue or soft tissue of the living body is formed by bundling plural rod-like modules 3 and integrally fixing the bundles. The modules 3 are recommended to have >=1 annular grooves on the circumferences and to be formed with tubular spaces (corresponding to Haversian canals) in a direction orthogonal with an axial direction. The sectional shapes of the modules 3 are preferably polygonal shapes having rounded corners and tubular spaces (corresponding to Volkmann's vessels) are preferably formed between the modules 3 and the modules 3. The module defective part for at least one piece exists and this part is preferably the tubular space 2 (corresponding to the spinal fluid vessel) in the axial direction. The modules 3 are preferably made from metals for the living body, bioactive ceramics, bioinert ceramics, high-polymer materials or >=2 kinds of the composites selected from the groups consisting thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modular artificial bone for supplementing a missing part in a living body due to a bone abnormality or breakage.

[0002]

2. Description of the Related Art In the case of abnormal bones or broken bones, generally, the bones in the abnormal part are removed, and the lost part is replaced with, for example, ceramics, stainless steel, which is said to be compatible with a living body. A titanium alloy or titanium alloy coated with apatite is embedded and complemented. These are called artificial bones.

[0003] Since these materials are difficult to process, they are produced in a machining factory by assuming a shape for each part in advance. Therefore, the conventional artificial bone can hardly be used for other parts than the assumed part.

[0004] Further, since it is difficult to shape the shape at the operating site, the manufacturer estimates the demand trend and selects an appropriate artificial bone according to the size from standard products produced in advance. Then, the artificial bone is embedded, the surroundings are complemented with the same kind of substance, and fixed with screws, cement, or the like.

[0005] That is, conventionally, the artificial bone is a ready-made artificial bone whose size can only be selected, and has a dense interior and rigidity such as metal and ceramics, which are originally difficult to make necessary corrections. Insert a higher artificial bone into the body,
The mainstream is to keep using it.

[0006]

The problem to be solved by the present invention is that these conventional artificial bones are materials with poor workability,
It is difficult to change to the appropriate size and shape. Moreover, at the operating site, it is impossible to correct a defect portion of a conventional artificial bone. Therefore, even if the selected artificial bone is considered inappropriate after the incision of the living body, it may be necessary to use the artificial bone as it is.

[0007] In addition, conventional artificial bones sometimes cause problems with the living body over time. There are several possible causes, but these can be broadly divided into two.

First, there is a difference in strength and flexibility between a living bone and an artificial bone. When a force is applied to the vicinity of the bone from the outside, an unnatural mechanical concentrated stress is applied, and a load is imposed on the living body. May cause irritation or pain. Furthermore, if the artificial bone has an inappropriate size or shape, there is an increased risk of generating unnecessary mechanical concentrated stress.

Second, as a problem of the conventional artificial bone, there is a problem of familiarity with a living body. Since the inside of the conventional artificial bone is uniform and dense, no vital activity is performed. That is, since blood vessels or various cells cannot enter the inside of the artificial bone, various problems occur at the interface between the living tissue and the artificial bone. As a countermeasure, a method has been adopted in which apatite having properties similar to actual living bone is coated on the surface of the artificial bone to increase affinity with the living body. However, since the coating layer is thin and blood vessels and living tissue do not enter the inside of the coating layer, integration with the bone tissue of the living body has been difficult even if the affinity is improved.

An object of the present invention is to provide an artificial bone member which is easy to obtain a shape and a size to be complemented, does not burden the living body, and is easily integrated with the bone tissue of the living body.

[0011]

SUMMARY OF THE INVENTION The modularized artificial bone of the present invention is an artificial bone for replacing a defective portion of a hard tissue or a cartilage tissue in a living body, and a plurality of rod-shaped modules are bundled and fixed integrally.

[0012] The module may include one or more annular grooves around the periphery, and a tubular space perpendicular to the axial direction may be formed.

It is preferable that the module has a polygonal cross section with rounded corners, and an axial tubular space is formed between the modules.

It is preferable that there is at least one module missing portion, and the missing portion is an axial tubular space.

[0015] The module may be a metal for living body, a bioactive ceramic, a bioinert ceramic, a polymer material,
Alternatively, it is desirably made of two or more composites selected from the group consisting of them.

The metals for living body include non-corrosive metals such as titanium, stainless steel and titanium alloy.

[0017] Bioactive ceramics include phosphoric materials such as HAP (hydrogen apatite) and TCP (tricalcium phosphate); Glass, Bio. Glass
And other silica-based materials.

The bioinert ceramics include alumina,
Examples include zirconia and carbon.

Examples of the polymer material include non-degradable materials such as high-molecular polyethylene, and biodegradable materials such as polylactic acid, polyglycolic acid, and collagen.

Examples of the complex include a complex composed of a combination of two or more of the above materials, such as a complex of apatite and collagen.

The module is fixed by a surgical thread, a metal band, a screw, or the like.

Further, as a connecting member to the living bone, a surgical thread, a titanium material, various ceramics and the like can be considered.
In particular, when using a bioabsorbable member for the module,
Preferably, a bioabsorbable yarn is used.

Each module has an appropriate cross-sectional shape and dimensions represented by a hexagon, and has a curved surface, holes, and wrinkles in addition to the annular groove. It may be used alone.

[0024] Therefore, an artificial bone into which blood vessels and cells easily enter or settle when bundled and fixed, or when used alone.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of one embodiment of the modular artificial bone of the present invention. FIG. 2 is a partially enlarged side view in which two modules constituting a modularized artificial bone are arranged. FIG. 3 is a sectional view taken along line III-III of FIG.

The modular artificial bone of the present invention bundles rod-shaped modules 3 having one or more annular grooves 3a and fixes them together.

As described above, a relatively small module 3 is prepared, and in an emergency operation site, the module 3 is bundled into a preferable shape and dimensions without preparing special devices, instruments and materials, and integrated. To create a modular artificial bone. By adjusting the number of modules 3,
The shape and dimensions can be changed to the optimum for the affected area to be treated.

It is necessary that the side surfaces of the module 3 contact each other as widely as possible and support each other, and the cross section of each module is preferably hexagonal so that the cross section has a honeycomb structure. Further, a polygon having a larger number of corners than a hexagon and closer to a circle, a star with a depression, or the like may be used.

Furthermore, by pulling out one central part of the module 3 bundled together, the cerebrospinal fluid hole 2 through which the bone marrow fluid originally passes can be obtained.
Can be shaped.

At the same time, as shown in the cross-sectional view of FIG. 3, in the section perpendicular to the axial direction of the module 3, by taking a corner, when the modules 3 are bundled, a thin tubular hole parallel to the axial direction is obtained. 5 (see FIG. 1). A similar hole exists in living bone and is called the Harvard's canal, which plays an important role mainly in supplying nutrients.

As shown in the enlarged side view of FIG. 2, the annular groove 3 is perpendicular to the module 3 in the axial direction.
By providing a, a tubular or fine gap 4 can be formed in a net shape in a direction perpendicular to the axis. A similar tube exists in living bone, and is called a Volkman tube, which is a gap mainly through blood vessels. The Volkman canal, which is a necessary organ inherent in living bone, can be freely formed by the present invention, and bone marrow fluid, nutrients, and blood are supplied abundantly, which hinders free growth of bone cells. Without artificial healing, the purpose of artificial bone can be fulfilled.

According to the present invention, when the size of each module is reduced, a complicated pipe-shaped space preferred by a living body or a cross-sectional shape having an axial hole is formed between the modules which are bundled and fixed integrally. Therefore, blood vessels and cells of the living body can actively grow and enter, and a favorable phenomenon as a module-to-module binder can be induced. Therefore, a living cell, such as a bone cell, wraps around each module, so that a situation close to natural healing can be brought about with time. In particular, unlike metals, modules made of a material with affinity for the living body, such as apatite, which is a part of the material that is inherent in the body, are almost taken into newly generated and grown living bones, It is possible to have a function equivalent to that of a conventional living body.

Furthermore, when a composite material of collagen and apatite, which has been receiving attention in recent years, is applied to the modules of the present invention, blood vessels and cells actively enter the gaps between the modules, so that each cell is activated. A large area can be taken. Therefore, at the same time, the composite material dissolves by the action of osteoclasts, and the activity of normal osteoblasts is promoted therein. With time, the living body itself becomes a missing part as its own regenerated bone. The effect of promptly complementing can be expected.

Such a composite material of collagen and apatite is modularized as in the present invention, and has a size and shape preferred by a living body, as compared with the conventional case where the composite material is inserted alone.
By bundling, fixing and embedding together, more spaces for blood vessels and cells to be activated can be provided, so that the healing efficiency is high and a result completely equivalent to natural healing can be obtained quickly.

(Embodiment) An embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a side view showing a state where the modular artificial bone of the present invention is complemented between living bones. FIG. 5 is a sectional view taken along line VV of FIG.

The typical sectional shape of the module 3 is hexagonal, and the facing size is about 3 mm for easy use. The length is adjusted to the missing portion, but a practical length is between 10 mm and 30 mm. In order to obtain a modular artificial bone having a required thickness, an appropriate number of modules 3 are bundled. For example, by bundling 18 modules 3 as shown in FIG. 5, a modular artificial bone having a diameter of about 14.2 mm on the opposite side is created. Alternatively, as shown in FIG. 1, by bundling the same 30 modules 3 as described above,
A modular artificial bone having a thickness of about 20 mm on the opposite side can be produced. In particular, by pulling out one center, a cerebrospinal fluid hole 2 through which bone marrow fluid originally passes is formed.

At the same time, by taking the corner of the cross section perpendicular to the axial direction of the module 3, a thin tubular hole 5 parallel to the axial direction can be formed when the modules 3 are bundled. Further, as shown in FIG. 2, by forming a curved surface on the side surface or providing a wrinkle, a tubular gap or a fine mesh-shaped gap 4 can be formed in a direction perpendicular to the axis.

The assembled modular artificial bone is embedded between living bones 8. Immediately after the installation of the modularized artificial bone, since there is naturally a gap between the living bone 8 and the separated state, the support 6 is temporarily provided. In the embodiment shown, it is sandwiched between two supports 6 and fixed. Support 6
A plate member made of, for example, titanium, which is slightly longer than the module 3 and has screw holes at both ends, is used. The fixing method is to fix to the living bone 8 with the screws 7 passed through the screw holes at both ends.

With time, an X-ray examination is performed from about three months after the intended effect, that is, about three months, which is the elapsed days when it can be determined that the patient has been cured. By X-ray examination,
If it is determined that the calcification around the modular artificial bone has progressed, the support 6 is loosened stepwise so as to adjust so that a stress is applied to a part to be treated. Finally, at the stage where the strength is secured, the support 6 can be removed.

Actually, in an experiment with a beagle dog, a remarkable healing effect was confirmed by a modular artificial bone in which modules made of apatite and collagen were bundled and fixed.

[0041]

According to the present invention, it is possible to provide a modular artificial bone which is easy to obtain the shape and dimensions to be complemented, does not burden the living body, and is easy to integrate with the bone tissue of the living body.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a modular artificial bone according to the present invention.

FIG. 2 is an enlarged side view in which two modules constituting a modularized artificial bone are arranged.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a side view showing a state where the modular artificial bone of the present invention is complemented between living bones.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thread 2 Cerebrospinal fluid hole 3 Module 3a Annular groove 4 Volkman tube 5 Harbors tube 6 Support 7 Screw 8 Living bone

 ──────────────────────────────────────────────────続 き Continuation of the front page (71) Applicant 500077904 E-com Co., Ltd. 5-11-3 Higashioi, Shinagawa-ku, Tokyo (72) Inventor Junzo Tanaka 3-15-6 Kashimadai, Tsukuba City, Ibaraki Prefecture (72) Inventor Masaki Kikuchi 3-15-15 Takezono, Tsukuba, Ibaraki Prefecture 109-202 (72) Inventor Toshiyuki Ikoma 670-82 Shimohirooka, Tsukuba City, Ibaraki Prefecture (72) Inventor Kunihiro Ota 4-10 Minamioi, Shinagawa-ku, Tokyo No. 2 Inside Tamachi Kogyo Co., Ltd. (72) No. Yokoyama, Inventor 5-11-3 Minamioi, Shinagawa-ku, Tokyo E-com Co., Ltd. F-term (reference) 4C081 AB03 AB04 BA13 BB08 CA021 CA171 CB011 CD121 CF021 CF031 CF061 CG02 CG03 CG05 DA03 DB08 DC15 4C097 AA01 BB01 BB09 CC01 CC05 CC12 CC15 CC20 DD02 DD05 DD06 DD07 DD08 DD09 DD10 EE02 EE08 EE19 MM02 SC01 SC04 SC10 4G030 AA17 AA36 AA60 AA61 AA67 BA35 CA07 GA36

Claims (5)

[Claims] 1. An artificial bone for replacing a defective portion of a hard tissue or a cartilage tissue in a living body, wherein a plurality of rod-shaped modules are bundled and fixed integrally. 2. The modular artificial bone according to claim 1, wherein the module has one or more annular grooves around the circumference, and a tubular space perpendicular to the axial direction is formed. 3. The module according to claim 1, wherein a cross-sectional shape of the module is a polygon with rounded corners, and an axial tubular space is formed between the modules. Modular artificial bone. 4. The modular artificial bone according to claim 1, wherein there is at least one module defect portion, and the defect portion becomes an axial tubular space. 5. The module according to claim 1, wherein the module is made of a biometal, a bioactive ceramic, a bioinert ceramic, a polymer material, or a composite of two or more kinds selected from the group consisting of these. The modular artificial bone according to any one of claims 1 to 4.