JP2011078745A - Bone prosthetic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a percutaneous vertebroplasty capable of introducing in a vertebral bone by using a formed insertion hole, relieving a throbbing pain of the patient by adhering to the inside space and filling, and distributing an improvement of QOL in patients by providing a material which can induce a new bone formation promptly. <P>SOLUTION: A spherical or elliptical material is composed of elastic metal materials, having an outer diameter capable of introducing to an insertion hole formed on a vertebral bone, and the vertebral body is filled with a lot of materials, and then they are deformed and adhered according to the shape in the vertebral body. The surface of the spherical or elliptical material is operated with a biocompatible treatment in order to induce a new bone formation on the surface and the inside promptly. Furthermore, the mechanical strength is improved as a bone reinforcement material by binding caused from the new bone formation between the adhered spherical or elliptical materials. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a bone grafting material.

  As a conventional treatment method for compression fractures in which the vertebral body is collapsed due to trauma, osteoporosis, bone tumor, etc., a method of filling a ceramic material in the vertebral bone (see, for example, Patent Document 1), or mainly PMMA resin ( A method of filling bone cement made of polymethyl methacrylate) is known (for example, see Patent Document 2). Recently, a bone grafting material in which a wire is wound in a coil shape and a calcium phosphate inorganic compound is filled in the central space thereof has been reported (for example, see Patent Document 3).

JP 2004-16289 A JP 2004-313738 A JP 2007-289551 A

  However, the prosthetic materials of Patent Documents 1 and 2 do not have elasticity, are less flexible than the adjacent vertebral bones, and have a problem that an excessive load is applied to cause a fracture. In particular, in bone cement therapy, the resin leaks into the blood and may cause shock symptoms due to blood drop and pulmonary embolism. Because of the need to do so, a reduction in patient quality of life has been reported. Furthermore, in the coil-shaped filling material of Patent Document 3, there is a possibility that the pressure is applied only in a specific direction, and the calcium phosphate inorganic compound arranged in the center of the coil does not necessarily function effectively for improving biocompatibility. Conceivable.

  The solution of such a problem is achieved by the present inventions (1) to (15) below.

  (1) Bone prosthesis used for percutaneous vertebroplasty, which has a spherical or ellipsoidal shape with at least one wire irregularly entangled, and passes through an introduction hole made in the vertebral bone Bone prosthesis characterized by having possible outer dimensions. Thereby, while relieving a patient's pain, the problem of the fracture of the said subject can be avoided and a new bone formation can be induced at an early stage.

  (2) The bone prosthetic material according to (1) above, wherein many irregular gaps are formed on the inside and inside of the spherical or ellipsoidal shape. As a result, bone-related cells such as osteoblasts can enter the voids of the bone filling material, and the generation of new bone can be induced at an early stage.

  (3) The bone grafting material according to any one of (1) and (2), wherein the spherical or ellipsoidal shape is provided with multi-directional elasticity. As a result, it can be smoothly introduced into the vertebral bone using the introduction hole, a plurality of bone prosthetic materials can be intimately filled in the internal space, and the elasticity of the patient in the multi-direction allows the patient to Pain can be reduced.

  (4) The bone grafting material according to any one of (1), (2), and (3) above, wherein the wire is made of titanium or an alloy thereof. As a result, a bone prosthetic material having high anti-corrosion properties and strong mechanical strength can be provided.

  (5) The shape of the sphere or ellipsoid is subjected to a physical, chemical, or electrical biocompatibility improving process, as described in any one of (1) to (4) above Bone filling material. Thereby, biocompatibility can be improved and a new bone production | generation can be induced at an early stage.

  (6) The bone grafting material according to any one of (1) to (5) above, wherein the electrical biocompatibility improving treatment is an anodizing treatment. Thereby, the oxide film which has many micropores on the metal surface is formed, and it can be used as a scaffold for new bone formation.

  (7) The electrical biocompatibility improving treatment is an anodic oxidation treatment in an electrolyte solution containing a calcium phosphate inorganic compound such as HAp. The bone filling material described. Thereby, the calcium phosphate inorganic compound adheres to the surface and inside of the oxide film layer of the titanium wire, biocompatibility can be improved, and new bone formation can be induced at an early stage.

  (8) The bone grafting material according to any one of (1) to (7) above, wherein a porosity of the bone grafting material is 60 to 90% in terms of weight. As a result, osteoblasts can enter the inside of the bone grafting material.

  (9) The bone grafting material according to any one of (1) to (8) above, wherein the wire has a diameter of 0.1 mm to 0.5 mm. Thereby, the porosity of a filling material can be 60-90%.

  (10) The bone grafting material according to any one of (1) to (9) above, wherein the length of the wire is 10 cm or more and 150 cm or less. As a result, it is possible to produce a bone prosthetic material having an outer dimension that can be introduced from an introduction hole provided in a vertebral body bone and having a porosity of 60 to 90%.

  (11) The bone grafting material according to any one of (1) to (10) above, wherein the maximum direction of the outer dimension of the bone grafting material is 2 mm or more and 5 mm or less. Thereby, the bone grafting material which has the outer dimension which can be introduce | transduced from the introduction hole given to the vertebral body bone can be produced.

(12) The bone prosthetic material according to any one of (1) to (11) above, wherein the volume per piece is 4 mm ³ or more and 70 mm ³ or less. Thereby, the bone grafting material which has the outer dimension which can be introduce | transduced from the introduction hole given to the vertebral body bone can be produced.

  (13) The bone grafting material according to any one of (1) to (12) above, wherein a plurality of bone grafting materials are filled in a single vertebral body. As a result, the bone prosthetic materials can be bonded to each other via the new bone.

  (14) The bone grafting material according to any one of (1) to (13) above, which has elasticity similar to that of vertebral cancellous bone. As a result, it is possible to solve the problem that an excessive load is applied to the adjacent vertebral bones to cause a fracture.

  (15) The bone grafting material according to any one of (1) to (14) above, wherein both ends of the wire rod of the bone grafting material are embedded in the bone grafting material. As a result, it is possible to prevent the both end portions of the material from piercing or catching on the in vivo tissue.

  (16) Without being limited to the percutaneous vertebroplasty described in (1) above, at least one kind selected from the group of the head bone, trunk bone, upper limb bone or lower limb bone The bone prosthetic material according to any one of (1) to (15) above, which is filled in any of a bone defect, a cartilage defect, or an intervertebral disc injury. Thereby, while a patient's pain is relieved, the production | generation of a new bone or a cartilage can be induced at an early stage.

  (17) With reference to FIG. 1 or FIG. 2 of the accompanying drawings, a bone prosthetic material substantially having the appearance described in claims 1 to 3. Thereby, it can be set as the bone grafting material which can induce new bone formation at an early stage.

  According to the present invention, the patient's pain can be suppressed and vertebral fractures can be prevented by filling and closely contacting the elastic sphere or ellipsoidal filling material into the vertebral body.

FIG. 4 is a view showing a spherical filling material before anodization. FIG. 5 is a view showing a spherical filling material after anodization. FIG. 4 is a view showing a surface SEM photograph of a spherical filling material after anodization. (A), (b) is the surface SEM photograph of the titanium wire outside the spherical filler, and (c), (d) are the SEM photographs inside the spherical filler. ... It is the figure which showed the EDX measurement result of the spherical filling material after anodization. (A) is a SEM photograph of the surface of a spherical filler, (b) is the detection result of oxygen, titanium, phosphorus and calcium in the region (a), (c) is titanium, (d) is oxygen, (e) is calcium , (F) represent the detection results of phosphorus, respectively. In addition, the vertical axis of the graphs (b) to (f) is the count number, and the horizontal axis represents the distance. FIG. 6 is a view showing a cross-sectional SEM photograph of a spherical filler after anodization. (A), (b) is the cross-sectional SEM photograph of the spherical filler before anodization, (c), (d) represents the cross-sectional SEM photograph of the spherical filler after anodization. ... is a diagram showing the elastic modulus of the spherical filler after anodization. Two weeks after the implantation of the rabbit tibia: The osteoid tissue by osteoblasts invades between the titanium wire rod (black part) of the spherical filler material, and the osteoid tissue reaches the central part of the spherical filler material. The periphery shows a photo that has already been ossified. 4 weeks after implantation of rabbit tibia: Represents a photograph filled with completely ossified bone tissue up to the deep part of the spherical filler. This represents a photograph in which the proliferation of chondrocyte-like cells (arrows) is observed toward the spherical filling material partially in contact with the growing cartilage zone. ... As a result of stress-strain curve, it is a figure showing that the elastic modulus of the spherical filling material approximates that of cancellous bone. FIG. 6 is a diagram showing that the spherical filling material has sufficient elastic force and restoring force even after applying periodic load 10,000 times as a result of the cyclic load-unloading test.

  (1) A titanium wire rod having a diameter of 0.1 mm and a length of 73 cm is irregularly entangled to produce a spherical filling material (FIG. 1) having an outer diameter of 4 mm.

  (2) The porosity of the spherical filler is 83%.

  (3) The spherical filler is anodized in the HAp-containing electrolyte as in (Example 1).

  (4) In the anodic oxidation, by adding ethanol to the electrolytic bath, uniform fixation of HAp and maintenance formation of communication holes are observed (FIG. 2).

  Examples will be given to describe the present invention in more detail, but the present invention is not limited to these examples.

10 vol. Hydroxyapatite fine particles of 2.5 g / L are added to and dispersed in an electrolytic bath containing 0.5% ethanol (0.5 mol / L sodium hydroxide, 0.05 mol / L trisodium phosphate, 0.05 mol / L hydrogen peroxide). It was. Next, the spherical filler was immersed in the bath and pulsed anodized. Electrolysis conditions at this time were a frequency of 300 Hz, a current density of 5 A / dm ² , an electrolysis time of 5 minutes, a waveform of a rectangular wave, a pure titanium plate as a counter electrode, and an interelectrode distance of 5 cm. The electrolysis was carried out with the current value during anodic oxidation being only positive (with offset). After electrolysis, washing with water, ultrasonic washing and drying were performed.

(Appearance photo)
FIGS. 1 and 2 show photographs of the appearance of the spherical filler and the spherical filler obtained by the anodic oxidation.

(SEM observation on the surface)
FIG. 3 shows a surface SEM photograph of the spherical filler obtained by the anodic oxidation. (a) and (b) show the surface SEM photograph of the titanium wire outside the spherical filler, and (c) and (d) show the SEM photograph inside the spherical filler. Thus, an oxide film is formed on the surface of the titanium wire by the anodic oxidation, and HAp sticking can be confirmed.

(EDX measurement)
The EDX measurement result of the spherical filling material obtained by the above anodic oxidation is shown in FIG. From the graphs of (b) and (c) to (f), detection peaks of oxygen, calcium and phosphorus are observed in the portion corresponding to the white fine particles in the SEM photograph of (a). HAp sticking can be confirmed on the surface of the wire.

(Cross section SEM observation)
FIG. 5 shows a cross-sectional SEM photograph of the spherical filler and the spherical filler obtained by the anodic oxidation. (A) represents the cross section of the spherical filling material before anodization and (b) after the anodization. From the cross-sectional SEM photograph of (d), it can be seen that an oxide film of about 5-15 μm is formed by the anodic oxidation.

(Compressive strength test)
FIG. 6 shows the results of compressive strength tests of three types of spherical fillers A, B, and C having different titanium wire amounts obtained by the anodic oxidation. A, B, and C are spherical fillers having a diameter of 0.1 mm and 4 mm in diameter made from titanium wires having a length of 110 cm, 73 cm, and 55 cm, respectively. The three curves are stress-strain curves obtained by performing an average of five compression strength tests on three types of spherical fillers. The elastic moduli of the spherical fillers A, B, and C obtained from the slope of the straight line portion of this curve were 553 MPa, 239 MPa, and 120 MPa, respectively. Since the elastic modulus of cancellous bone has been reported to be 50-500 MPa (J Mater Sci: Mater Med. 19 (2008) 451-457), spherical fillers B and C have the same elasticity as cancellous bone, respectively. It was shown to have strength. In the above embodiment, the titanium wire is used. However, it is also possible to use a wire made of a polymer other than the titanium wire.

  Effect of filling bone filling material of the present invention into rabbit bone

(Histological search)
The tissue was embedded in the femur and tibia bones of adult Japanese rabbits and sacrificed 1, 2, and 4 weeks after implantation, and the bone tissue containing the material was collected. Furthermore, a hard tissue specimen was prepared, stained with Villa Neva Goldner, and observed with an optical microscope.

(Entry of bone tissue into bone filling material and confirmation of its existence)
As early as one week after implantation, the osteoid tissue by osteoblasts invaded between the titanium wire rods (black part) of the spherical filling material from the surrounding trabeculae, and a part of the tissue was already calcified. Two weeks after implantation, the osteoid tissue reached the central part of the spherical filler, and the peripheral part was already ossified (FIG. 7, a map-like part between the wires). After 4 weeks of implantation, the bone filling material was completely filled up to the deep part of the spherical filling material. (FIG. 8) Further, proliferation of chondrocyte-like cells (arrows) was observed toward the spherical filling material partially in contact with the growing cartilage band. (FIG. 9) This is a finding that the spherical filler has a strong affinity not only with bone but also with cartilage tissue.

  Experiments with resilience similar to vertebral cancellous bone

  The result of the compressive strength test of three types of spherical fillers D, E, and F having different amounts of titanium wire is shown in FIG. D, E, and F are spherical fillers having a diameter of 0.1 mm and 4 mm in diameter made from titanium wires having a length of 110 cm, 73 cm, and 55 cm, respectively. The three curves are stress-strain curves obtained by performing an average of five compression strength tests on three types of spherical fillers. The elastic modulus of the spherical fillers D, E, and F obtained from the slope of the straight line portion of this curve was 192 MPa, 153 MPa, and 88 MPa, respectively. Since the elastic modulus of cancellous bone is reported to be 50-500 MPa (J Mater Sci: Mater Med. 19 (2008) 451-457), these three types of spherical fillers are similar to cancellous bone, respectively. It was shown to have elastic strength. Together with the results in FIG. 6, it was revealed that the spherical filling material has almost the same elastic strength as cancellous bone regardless of the presence or absence of anodizing treatment.

  Reproduction test of load on vertebral bones in daily life

  FIG. 11 shows the results of a cyclic load-unloading test in which a 10-MPa load-unload was repeatedly applied to a 4-mm diameter spherical filler made from a titanium wire having a diameter of 0.1 mm and a length of 73 cm. The four curves are stress-strain curves in the first period, the 100th period, the 1000th period, and the 10000th period, respectively. As shown in the first cycle curve, a strain of about 15% was generated when a load of 10 MPa was applied, but about 90% of the strain was eliminated when the load of 10 MPa was removed. Furthermore, it became clear that the behavior of the curve at the 10,000th cycle is similar to the behavior of the curve at the first cycle. From these results, the spherical filling material is sufficient in the daily life that is periodically loaded because the elastic force and the restoring force are maintained even if the load of 10,000 times is periodically added to the spherical filling material. It became clear that it had elastic force and restoring force.

  Currently, percutaneous vertebroplasty with bone cement is mainly performed as a treatment for vertebral body compression fractures, but it is known that there are problems such as fracture due to excessive load and pulmonary embolism due to leakage. By using the spherical or ellipsoidal material developed as described above, it is possible to provide a new treatment method that overcomes these problems.

Claims (17)

  Bone prosthesis used in percutaneous vertebroplasty. It has a spherical or ellipsoidal shape with at least one wire irregularly entangled, and can pass through an introduction hole made in the vertebral bone. Bone prosthetic material characterized by having dimensions.   2. The bone grafting material according to claim 1, wherein a number of irregular gaps are provided on the surface and the inside of the spherical or ellipsoidal shape.   The bone prosthetic material according to claim 1 or 2, wherein multi-directional elasticity is applied to the shape of the sphere or ellipsoid.   The bone prosthetic material according to any one of claims 1 to 3, wherein the wire is made of titanium or an alloy thereof.   The bone grafting material according to any one of claims 1 to 4, wherein the spherical or ellipsoidal wire is subjected to physical, chemical or electrical biocompatibility treatment.   The bone grafting material according to any one of claims 1 to 5, wherein the electrical biocompatibility improving treatment is an anodic oxidation treatment.   The bone grafting material according to any one of claims 1 to 6, wherein the electrical biocompatibility improving treatment is an anodizing treatment in an electrolyte solution containing a calcium phosphate inorganic compound such as HAp. .   The bone grafting material according to any one of claims 1 to 7, wherein a porosity of the bone grafting material is 60 to 90% in terms of weight.   The bone grafting material according to any one of claims 1 to 8, wherein a diameter of the wire is 0.1 mm or more and 0.5 mm or less.   The length of the said wire is 10 cm or more and 150 cm or less, The bone grafting material in any one of Claims 1-9 characterized by the above-mentioned.   The bone grafting material according to any one of claims 1 to 10, wherein a maximum direction of an outer dimension of the bone grafting material is 2 mm or more and 5 mm or less. The bone prosthetic material according to any one of claims 1 to 11, wherein the volume per piece is 4 mm ³ or more and 70 mm ³ or less.   The bone grafting material according to any one of claims 1 to 12, wherein a plurality of the bone grafting materials are filled and used in a single vertebral body.   The bone grafting material according to any one of claims 1 to 13, wherein the bone grafting material has elasticity similar to that of vertebral body cancellous bone.   The bone grafting material according to any one of claims 1 to 14, wherein both ends of the wire rod of the bone grafting material are embedded in the bone grafting material.   Without being limited to the percutaneous vertebroplasty according to claim 1, at least one bone defect selected from each group of head bone, trunk bone, upper limb bone or lower limb bone, The bone filling material according to any one of claims 1 to 15, which is filled into a cartilage defect portion or an intervertebral disc injury portion.   Bone prosthesis substantially as described above with reference to FIG. 1 or 2 of the accompanying drawings.