JP2006230722A - Biomaterial for artificial cartilage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biomaterial for an artificial cartilage, which is soft, has deformation characteristics close to the ones of the cartilage of a living body, is surely connected with a living body bone with strong fixing force and does not cause fine powder due to friction. <P>SOLUTION: The biomaterial for the artificial cartilage is provided with the deformation characteristics close to the ones of the cartilage of the living body by making an organic fiber into a composite tissue of a multi-axis three dimensional woven composition or braided composition with three or more axes or complex composition as a core material 1. On one surface or both surfaces of the core material 1, plates 2 composed of a biodegradably absorbable polymer including bioactive bioceramic powder with many through-holes 2a and 2b formed in a thickness direction are laminated. By filling a biodegradable and absorbable material 5 having osteoconductivity and/or osteoinductivity to be biodegraded faster than the plates in the through-holes of the plates 2, connection with the living body bone is ensured, the fixing force is increased and the generation of fine powder is eliminated as well. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a biomaterial for artificial cartilage that is expected to be used as an artificial intervertebral disc, an artificial meniscus, or various articular cartilages.

  One of the promising biomaterials for artificial cartilage is an ultra-high-molecular-weight polyethylene sphere that serves as a ball bearing between upper and lower metal plates such as titanium alloy, making it movable as an intervertebral disc. There is an artificial intervertebral disc with a sandwich structure. This artificial intervertebral disc allows the movement of the upper and lower vertebral bodies, but its dynamic behavior is very different from that of living body intervertebral discs. There are also all-metal artificial discs with springs inside, but their dynamic behavior is also far away from the living intervertebral disc, and it is difficult to think that the intervertebral disc can be replaced.

  Therefore, the applicant of the present invention has continuous pores on both surfaces of a core material made of a fiber structure in which organic fibers are multiaxial three-dimensional woven or knitted structures of three or more axes or a composite structure thereof, and is bioactive. A biomaterial for artificial cartilage, which is used as a self-supporting artificial intervertebral disc, in which spacers made of a porous body of biodegradable absorbable polymer containing bioceramics powder are laminated, has already been proposed (Patent Document 1). ).

  When such a biomaterial for artificial cartilage is inserted between the upper and lower vertebral bodies as an artificial intervertebral disc, the core material made of a fiber structure has the same mechanical flexibility (movability) as the intervertebral intervertebral disc. Is very biomimetic, and the laminated spacers directly connect with the upper and lower vertebral bodies, and replace the bone tissue over time to fix the core material surface and the upper and lower vertebral bodies, so the function of the intervertebral disc in the living body Can be effectively substituted.

However, although the biomaterial for artificial cartilage described above is extremely effective for the connection with the vertebral body because the spacer has a strong osteoconductivity or osteoinductivity, it is accompanied by the penetration and growth of the bone tissue into the spacer. Therefore, the replacement of the spacer with bone tissue and the incomplete connection between the vertebral body and the biomaterial for artificial cartilage will weaken the bonding and fixing force between the upper and lower vertebral bodies. I was worried. Moreover, since the spacer which consists of porous bodies is weak, there also existed a possibility that the peripheral part of a spacer might wear and fine powder might generate | occur | produce.
Japanese Patent Laid-Open No. 2003-230583

  The present invention has been made in view of the above circumstances, and has a flexible deformation property similar to that of living body cartilage using a tissue structure of organic fibers as a core material, and is firmly connected to living bones and has a large fixing force. An object of the present invention is to provide a biomaterial for artificial cartilage that does not generate fine powder due to wear.

  In order to solve the above-mentioned problems, the biomaterial for artificial cartilage according to the present invention is a core material composed of a tissue structure in which organic fibers are multiaxial three-dimensional or three-dimensional woven tissue or knitted tissue or a composite structure thereof. A plate made of biodegradable and absorbent polymer containing bioactive bioceramic powder and laminated with a plate with many through holes in the thickness direction is laminated on one or both sides of A hole or a part of the through hole is filled with a biodegradable and absorbable material having osteoconductivity and / or osteoinductivity and faster in vivo degradation than the plate. .

  In the biomaterial for artificial cartilage of the present invention, a biodegradable and absorbable material having osteoconductivity and / or osteoinductivity and faster in vivo degradation than the plate is formed on the surface or both surfaces of the plate. It is preferable to laminate | stack the coating layer which becomes. Biodegradable / absorbable materials include biodegradable / absorbable polymer porous bodies having continuous pores therein, bioceramics powder having osteoconductivity, and / or cytokines having osteoinductivity, bone A drug containing at least one of an inductive agent, an osteoinductive factor, a bioceramic powder having osteoconductivity in collagen, and / or a cytokine having osteoinductive ability, an osteoinductive ability Those containing at least one of a drug possessed and an osteoinductive factor are preferred.

  When the biomaterial for artificial cartilage of the present invention is inserted between the vertebral bodies of the cervical vertebra or the spine (particularly the lumbar vertebra) as an artificial intervertebral disc, for example, organic fibers are combined with a multiaxial three-dimensional woven tissue or knitted tissue or a composite tissue thereof. Since the core material made of the tissue structure has the same mechanical strength and flexibility as the intervertebral disc of cartilage, and its deformation is extremely biomimetic, it sufficiently serves as an intervertebral disc. And the biodegradable and absorbable material filled in the through-hole of the plate laminated on the core material decomposes faster than the plate by contact with body fluid, and due to its vigorous osteoconductivity and / or osteoinductivity Immediately, the bone tissue is formed by conduction and / or induction, and replaces the bone tissue at an early stage to directly connect with the vertebral body. On the other hand, the plate is much stronger than the biodegradable and absorbable material in the through hole, and the rate of decomposition and absorption is substantially balanced with the speed of bone tissue growth, so Decomposition progresses later than the degradable and absorbable material, so there is enough time for the biodegradable and absorbable material in the through hole to be replaced with bone tissue to some extent by being present at the interface between the vertebral body and the core material. Maintain strength. For this reason, even if the core material of the artificial cartilage biomaterial repeatedly undergoes biomimetic deformation under a large clamping force between the upper and lower vertebral bodies, fine powder is generated from the plate, and the biodegradable absorbability in the through hole Fine powder is not generated from the material. Then, the bone tissue grows in parallel with the gradual destruction of the plate with the subsequent decomposition and absorption of the plate, and the connection between the plate and the bone tissue proceeds. Finally, the plate is completely separated from the bone tissue. Since the core material and the vertebral body are directly coupled by the replacement, a sufficient fixing force for coupling with the vertebral body is obtained.

  Further, a living body for artificial cartilage in which a coating layer made of a biodegradable and absorbable material having osteoconductivity and / or osteoinductivity and faster in vivo degradation than the plate is laminated on the surface or both sides of the plate. When the material is inserted between the upper and lower vertebral bodies, for example, as an artificial intervertebral disc, there is an advantage that bone tissue is formed almost uniformly on the surface of the plate at an early stage. In particular, the covering layer is made of the biodegradable absorbable polymer described above. In the case where the porous material contains at least one of bioceramics powder having osteoconductivity and / or cytokine having osteoinductive ability, drug having osteoinductive ability, and osteoinductive factor, This coating layer acts as a cushioning material and is in close contact with the vertebral body by compressive deformation, facilitating the penetration of osteoblasts into the porous body, so that the conduction formation and / or induction formation of the bone tissue is further accelerated. Te, so that the bone tissue is formed on the plate surface within a short period of time.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  1 is a perspective view of a biomaterial for artificial cartilage according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 3 is an explanatory view of an example of use of the biomaterial for artificial cartilage. FIG. 4 is a cross-sectional view of the artificial cartilage biomaterial plate.

  The artificial cartilage biomaterial 11 is a block-shaped biomaterial having a substantially front-rear circular planar shape in which the first half is formed in a rectangular shape and the second half is formed in a semicircular shape. As shown in FIG. The replacement type intervertebral disc is used by being inserted from the front (left side in FIG. 3) between the upper and lower vertebral bodies 20 and 20 of the spine (particularly the lumbar vertebra) and the cervical vertebra. The size of the biomaterial 11 for artificial cartilage differs depending on whether it is used as an artificial disc for cervical vertebrae or an artificial disc for lumbar vertebrae, and is different for adults and children. For example, the standard size when used as an artificial vertebral disc for adult cervical vertebrae has a width dimension of about 18 mm, a front-rear dimension of about 15 mm, and a thickness dimension of about 7 mm. When used, the standard size is about 40 mm in width, about 30 mm in front and back, and about 15 mm in thickness.

  As shown in FIGS. 1 and 2, the biomaterial 11 for artificial cartilage is formed by laminating plates 2 and 2 having large and small through holes 2 a and 2 b on both upper and lower surfaces of a core material 1. 2a and 2b are filled with the biodegradable absorbent material 5. And three biodegradable and absorbable pins 3 are penetrated by the core material 1 and the plate 2 using the through holes 2a and 2b, and the sharp ends of each pin 3 are from the surface of the plates 2 and 2. It protrudes a little.

  The core material 1 is composed of a tissue structure in which an organic fiber is a three-dimensional woven or knitted structure or a composite structure thereof, and has mechanical strength and flexibility similar to those of cartilage such as a living intervertebral disc. And is a core material that is extremely biomimetic (biomimetic) in deformation. The tissue structure of the core material 1 is the same as the tissue structure described in Japanese Patent Application No. 6-254515 (Japanese Patent Laid-Open No. 7-148243) already filed by the present applicant, and its geometrical structure. When the target shape is represented by the number of dimensions and the number of orientations of the fiber array is represented by the number of axes, a structure composed of a multi-axis-three-dimensional structure having three or more axes is preferably employed.

  The three-axis-three-dimensional structure is a three-dimensional structure of fibers in three vertical, horizontal, and vertical directions. A typical shape of the structure is a thick bulk like the core material 1 described above. The shape (plate shape or block shape) may be a cylindrical shape or a honeycomb shape. This three-axis-three-dimensional structure is classified into an orthogonal structure, a non-orthogonal structure, an entangled structure, a cylindrical structure, and the like depending on the structure. In addition, a multi-axis-three-dimensional structure having four or more axes has a strength isotropy of the structure by arranging multi-axis orientations such as 4, 5, 6, 7, 9, and 11 axes. It can be improved. And by these selections, the more biomimetic core material 1 more closely resembling a living cartilage tissue can be obtained.

  The internal porosity of the core material 1 made of the above-described structural structure is preferably in the range of 20 to 90%, and when it is less than 20%, the core material 1 becomes dense and the flexibility and deformability are impaired. Therefore, the core material of the biomaterial for artificial cartilage is unsatisfactory. On the other hand, if it exceeds 90%, the compressive strength and shape retention of the core material 1 are lowered, so that it is also unsuitable as a core material for biomaterials for artificial cartilage.

  The organic fiber constituting the core material 1 is a bioinert synthetic resin fiber, for example, a fiber such as polyethylene, polypropylene, polytetrafluoroethylene, or an organic core fiber covered with the above bioinert resin. For example, coated fibers that are bioinactive are preferably used. In particular, a coated fiber having a diameter of about 0.2 to 0.5 mm obtained by coating a core fiber of ultrahigh molecular weight polyethylene with a linear low density polyethylene film has strength, hardness, elasticity, and ease of knitting. It is the most suitable fiber in terms of size. In addition to this, a fiber having bioactivity (for example, having a bone conduction ability or an osteoinductive ability) can be selected.

  The structure of the core material 1 is disclosed in detail in the aforementioned Japanese Patent Application No. 6-254515 (Japanese Patent Application Laid-Open No. 7-148243), and will not be described further.

  The plates 2 and 2 laminated on the upper and lower surfaces of the core material 1 are perforated with large and small through holes 2a and 2b in a nonporous plate made of a biodegradable absorbent polymer containing bioactive bioceramic powder. In this case, a plate obtained by melt molding the above-mentioned polymer and through-holes are drilled, or a melt-molded product is further forged in the cold (temperature range above the glass transition temperature of the polymer and below the melting temperature). A plate obtained by drilling through holes is used.

  The latter forged plate may be a forged one-time or a plurality of times of forging, but in particular, a plate that has been forged once again with the machine direction changed once more. A structure in which molecular chains or crystals of a polymer are oriented along a number of randomly different reference axes in the axial direction, or a structure in which a large number of clusters having a number of these randomly different reference axes are assembled, or a molecular chain Since crystals and clusters have a structure oriented in a three-dimensional direction, there is an advantage that mechanical deterioration and destruction are hardly caused even when deformation is repeated by receiving external force. Therefore, the biomaterial 11 for artificial cartilage in which the through-holes 2a and 2b are drilled in such a forged plate 2 and laminated on both surfaces of the core material 1 is used as an artificial intervertebral disc between the vertebral bodies 20 and 20. When inserted, even if the plate 2 is repeatedly deformed together with the core material 1 due to the clamping force between the upper and lower vertebral bodies 20, 20, no mechanical deterioration or destruction occurs until most of the plate 2 is decomposed and absorbed. Also, even if a through-hole is drilled in a once forged plate, it is compressed and becomes dense, and the polymer molecular chains and crystals are oriented obliquely toward one reference axis or reference plane, or as described above Therefore, the mechanical strength is improved and it is difficult to break as compared with a plate formed only by melt molding.

  Examples of the biodegradable absorbable polymer used as a raw material for the plate 2 include polylactic acid such as poly-L-lactic acid, poly-D-lactic acid, poly-D, and L-lactic acid, or L-lactide, D-lactide, Any one of DL-lactide, a copolymer by glycolide, a copolymer by caprolactone, a copolymer by dioxanone, a copolymer by ethylene oxide, a copolymer by propylene oxide, etc. are suitable, and these may be used alone or in combination. Used. Among these polymers, polylactic acid is 50,000 in view of the speed and period of decomposition and absorption of the plate 2 in balance with the growth of bone tissue, the mechanical strength that can withstand the clamping force of the vertebral body, etc. Those having a viscosity average molecular weight of about ˜500,000 are preferable.

  The bioceramic powder to be contained in the above-mentioned biodegradable and absorbable polymer plate 2 is bioactive, has good bone conductivity and good biocompatibility, and has not been calcined or calcined hydroxyapatite. , Powders such as dicalcium phosphate, tricalcium phosphate, tetracalcium phosphate, octacalcium phosphate, calcite, serabital, diopsite, and smallpox are used. And what adhered the alkaline inorganic compound and the basic organic substance to the surface of these powders can also be used. Among these, bioresorbable bioceramic powders that are totally resorbed in vivo and completely replaced with bone tissue are preferable. In particular, uncalcined and unfired hydroxyapatite, tricalcium phosphate, octacalcium Phosphate is optimal because it has extremely high activity, excellent osteoconductivity, low toxicity, and is absorbed by the living body in a short period of time. As these bioceramic powders, those having an average particle size of 10 μm or less, preferably those having a particle size of about 0.2 to 5 μm are used.

  The content of the bioceramic powder is preferably 25 to 60% by mass, and if it exceeds 60% by mass, the plate 2 becomes brittle and is easily broken by the clamping pressure of the vertebral body. In addition, since the conduction formation of the bone tissue is delayed, there is a disadvantage that it takes a long time for the plate 2 to replace the bone tissue. A more preferable content of bioceramics is 30 to 50% by weight.

  In addition to the bioceramic powder described above, this plate 2 may contain appropriate amounts of various cytokines having osteoinductive ability and drugs having osteoinductive ability. There is an advantage that the core material 1 and the vertebral body 20 are directly coupled to each other at an early stage because the growth and replacement of the tissue is remarkably promoted. In addition, an osteoinductive factor (Bone Morphogenetic Protein) may be included in the plate 2, and in that case, osteoinduction is expressed, which is more effective for binding integration. If necessary, drugs having various medicinal effects (such as therapeutic drugs) may be included in the plate 2. Furthermore, both surfaces of the plate 2 may be subjected to oxidation treatment such as corona discharge, plasma treatment, hydrogen peroxide treatment, etc. In this case, the wet characteristics of the bioceramic powder exposed on the surface are improved and bone cells to be proliferated Invasion and growth become effective.

  The above-mentioned bioceramic powder, cytokine, drug, osteoinductive factor, etc. may be sprayed on the surface of the core material 1, in which case the surface of the core material 1 is bioactivated and the bone tissue formed by conduction is this Since it is bonded to the activated surface, there is an advantage that the vertebral body 20 and the core material 1 are directly bonded in a short time and the strength is maintained.

  The plate 2 is preferably perforated with a large number of large and small through-holes 2a and 2b so as to have an aperture ratio of 15 to 60%. Thus, the aperture ratio is 15 to 60%. The perforated plate 2 is strong enough to withstand the clamping force of the upper and lower vertebral bodies 20 and 20, and the entire plate has a moderate rate of decomposition and resorption and is balanced with the bone tissue growth rate. It has the advantage that it can be firmly connected to the vertebral body 20 by being replaced with bone tissue. When the aperture ratio is higher than 60%, the strength of the plate 2 is reduced, and when the aperture ratio is lower than 15%, the period required for the decomposition and absorption of the plate 2 becomes longer. Is not preferable because replacement with bone tissue tends to be delayed.

  The diameters of the large and small through holes 2a and 2b are not particularly limited, but it is preferable to set the diameters of the large and small through holes 2a and 2b within a range of 0.5 to 5 mm. If the diameter of the large through-hole 2a exceeds 5 mm, the through-hole 2a is not completely buried by the growing bone tissue, and it may be difficult to grow and form the bone tissue on the entire surface of the core material 1. It is not preferable.

  The plate 2 may be perforated by dispersing through holes having the same diameter without distinguishing between large and small through holes. Further, the shape of the through holes 2a and 2b is not limited to a true circle as in this embodiment, but may be any hole shape such as an ellipse, an oval, a rectangle, other polygons, and an indefinite shape. Can do. Therefore, for example, the plate 2 can be configured in a net shape by arranging through-holes having the same square size vertically and horizontally.

  The thickness of the plate 2 is suitably in the range of 0.3 to 1.2 mm, particularly preferably about 1 mm. Thus, the plate 2 having a limited thickness has a strength capable of withstanding the clamping pressure between the upper and lower vertebral bodies 20, 20, and is decomposed and absorbed in about one year at a speed balanced with the growth of the bone tissue. There is an advantage that it can be completely replaced and firmly connected to the vertebral body 20. If the thickness of the plate 2 is less than 0.3 mm, the strength is insufficient and the plate 2 may be broken by the clamping force of the vertebral bodies 20 and 20. If the thickness is greater than 1.2 mm, the period required for the decomposition and absorption of the plate 2. As a result, the inconvenience occurs that the replacement with the bone tissue is delayed.

  The biodegradable / absorbable material 5 filled in the through holes 2a and 2b of the plate 2 has osteoconductivity and / or osteoinductivity, is excellent in bioactivity, and is decomposed in vivo in the plate 2. Faster material. The biodegradable and absorbable material 5 does not necessarily need to be filled in all the through holes 2a and 2b, and may be filled in only some of the through holes, for example, only in the large through holes 2a. .

  The biodegradable / absorbable material 5 is a biodegradable / absorbable polymer porous body having continuous pores therein, and has the above-described bioceramic powder having osteoconductivity and / or osteoinductivity. Those containing at least one of various cytokines, drugs having osteoinductive ability, and osteoinductive factor (BMF) are preferably used. In addition, a porous body containing at least one of bioactive bioceramics powder in collagen and / or various cytokines having osteoinductive ability, drugs having osteoinductive ability, and osteoinductive factor (BMF) Nonporous materials are also preferably used. And the nonporous body which made biobiodegradable polymer contain more bioceramics powder than the plate 2 is also used. The content of the bioceramic powder in these porous or nonporous materials is preferably 60 to 90% by mass. The content of cytokine having osteoinductive ability, drug having osteoinductive ability, and osteoinductive factor may be appropriate. If necessary, the porous body or collagen may contain drugs having various medicinal effects (such as therapeutic drugs).

  The porous body of the biodegradable / absorbable material 5 is not required to have a high strength, and needs to be quickly decomposed and replaced with bone tissue that is conductively formed and / or induced and formed faster than the plate 2. Therefore, the biodegradable and absorbable polymer used as a raw material thereof is safe, relatively quick to decompose, not very brittle, amorphous or a mixture of crystalline and amorphous poly-D, L-lactic acid, L-lactic acid. And D, L-lactic acid copolymer, lactic acid and glycolic acid copolymer, lactic acid and caprolactone copolymer, lactic acid and ethylene glycol copolymer, lactic acid and para-dioxanone copolymer, etc. are suitable. These may be used alone or in combination of two or more. Among these polymers, those having a viscosity average molecular weight of about 50,000 to 1,000,000 are preferably used in consideration of the ease of forming a porous body and the period of decomposition and absorption in vivo.

  In consideration of physical strength, osteoblast invasion and stabilization, the porous body made of the above polymer has a porosity of 50 to 90%, and continuous pores account for 50 to 90% of the total pores. The pore diameter is preferably about 100 to about 400 μm. When the porosity exceeds 90% and the pore diameter is more than 400 μm, the physical strength of the porous body is lowered and becomes brittle. On the other hand, when the porosity is less than 50%, the continuous pores are less than 50% of the total pores, and the pore diameter is smaller than 100 μm, it is difficult for the body fluid and osteoblasts to enter, and the porous body is hydrolyzed and the bone tissue is grown. And the time required for the porous body to replace the bone tissue becomes longer. A more preferable porous body has a porosity of 60 to 80%, continuous pores occupying 70 to 90% of the total pores, and continuous pores having a pore diameter of about 150 to about 350 μm.

  The method for producing the porous body is not particularly limited, and any method may be used. For example, the above biodegradable absorbent polymer is dissolved in a volatile solvent and a bioceramic powder is mixed to prepare a suspension. The suspension is made into a fiber by means of spraying or the like, and the fibers are entangled. The above fiber aggregates are packed into the through holes 2a and 2b of the plate 2 before lamination, and heated to a temperature at which the fibers can be fused, so that the fibers are partially fused. It can be produced by a method of forming a porous fiber fusion aggregate and immersing the fiber fusion aggregate in a volatile solvent together with the plate 2 to change the shape into a porous body.

  The pin 3 that penetrates the core material 1 and the plates 2 and 2 on both sides in the vertical direction is made of the above-described lactic acid-based polymer similar to the plate 2, and polymer molecules or A pin whose crystal is oriented to increase the strength is preferably used. Both ends of the pin 3 protruding from the plates 2 and 2 are formed in a conical shape having a height of about 0.3 to 2 mm. The artificial cartilage biomaterial 11 is used as an artificial intervertebral disc between the vertebral bodies 20 and 20. When inserted, both ends of the pin 3 bite into the end plates of the vertebral bodies 20 and 20 so that the displacement / reversion of the artificial cartilage biomaterial 11 is reliably prevented. The thickness of the pin 3 is about 0.5 to 3 mm, preferably about 1 mm, so that the pin 3 is not broken by the clamping force of the vertebral bodies 20 and 20.

  The number of pins 3 may be one, but in the case of one, there is a disadvantage that even if the lateral displacement of the artificial cartilage biomaterial 11 can be prevented, the rotation of the artificial cartilage biomaterial 11 cannot be prevented. Therefore, two or more, preferably three may be penetrated in a symmetrical arrangement as shown in FIGS. If the three pins 3 are penetrated in this way, there is an advantage that the biomaterial 11 for artificial cartilage can be stably mounted between the upper and lower vertebral bodies 20 and 20 by supporting three points. However, in the case of a small size biomaterial 11 for artificial cartilage used as a total replacement type artificial disc for cervical vertebrae, it is only necessary to penetrate two pins 3 on the left and right.

  The pin 3 preferably contains an appropriate amount of the above-mentioned bioceramic powder, various cytokines, drugs, osteoinductive factors, and the like. In some cases, the pin 3 and the plates 2 and 2 may be integrated by adhesion or fusion. Furthermore, the pin 3 may be divided into upper and lower portions, and the upper end portion of the upper pin and the lower end portion of the lower pin may protrude from the surfaces of the upper and lower plates 2 and 2.

  When the artificial cartilage biomaterial 11 configured as described above is inserted from the front between the vertebral bodies 20 and 20 of the cervical vertebra or spine (particularly the lumbar spine) as an artificial intervertebral disc, for example, as shown in FIG. The sharp ends of the pin 3 projecting from the surfaces of the plates 2 and 2 bite into the end plates of the vertebral bodies 20 and 20, and are pinched between the vertebral bodies 20 and 20 without causing displacement or dislocation. The core material 1 made of an organic fiber tissue structure having the same mechanical strength and flexibility as that of the intervertebral disc is transformed into biomimetic and sufficiently fulfills the role as an intervertebral disc. And the biodegradable and absorbable material 5 filled in the through holes 2a and 2b of the plates 2 and 2 is decomposed faster than the plates 2 and 2 by contact with the body fluid, and its vigorous bone conductivity and / or Due to the osteoinductivity, the bone tissue is promptly formed and / or induced, and is replaced with the bone tissue at an early stage and directly connected to the vertebral bodies 20 and 20. On the other hand, the plates 2 and 2 are much stronger than the biodegradable and absorbable material 5 in the through holes 2a and 2b, and the speed of decomposition and absorption is substantially balanced with the speed of bone tissue growth. Therefore, the decomposition proceeds later than the biodegradable absorbable material 5, so that the biodegradable absorbable material 5 in the through-hole existing at the interface between the vertebral bodies 20, 20 and the core material 1 has a certain degree of bone tissue. Maintain sufficient strength until replaced. For this reason, even if the core material 1 of the biomaterial 11 for artificial cartilage repeats biomimetic deformation under a large clamping force between the upper and lower vertebral bodies 20, 20, fine powder is generated from the plates 2, 2 or penetrated Fine powder is not generated from the biodegradable absorbent material 5 in the pores. Then, the bone tissue grows in parallel with the gradual destruction of the plates 2 and 2 with the subsequent decomposition and absorption of the plates 2 and 2, and the connection between the plates 2 and 2 and the bone tissue proceeds. In particular, the plates 2 and 2 are completely replaced with the bone tissue, and the core material 1 and the vertebral bodies 20 and 20 are directly coupled to each other.

  In the biomaterial 11 for artificial cartilage described above, a perforated plate 2 in which fine irregularities as shown in FIG. 4 are formed on both front and back surfaces may be used as the perforated plate laminated on both surfaces of the core material 1. . The biomaterial for artificial cartilage in which the through-hole 2a (2b) of the perforated plate 2 having such fine irregularities is filled with the biodegradable absorbent material 5 described above and laminated on both surfaces of the core material 1 is artificially made. When inserted between the vertebral bodies 20 and 20 as an intervertebral disc, the convex and concave portions 2c on the surface of the plate 2 can bite into the end plate of the vertebral body 20 and prevent displacement of the biomaterial for artificial cartilage and slippage. There is an advantage that the contact area with the body 20 is remarkably increased and the bonding property is further improved, and the uneven projection 2c on the back surface of the plate 2 bites into the core material 1 so that the relative position between the plate 2 and the core material 1 is increased. There is an advantage that the deviation can be prevented. Therefore, in this case, the pin 3 can be omitted.

  The fine unevenness may have a random uneven shape, but the uneven protrusion 2c may be formed into a small quadrangular pyramid shape (for example, a regular square base having a side of about 0.6 mm and a height of about 0.3 mm). A quadrangular pyramid shape is preferable in which a large number of arrays are formed without gaps in the front, rear, left, and right. When such irregularities are formed, the quadrangular pyramid-shaped convex portions 2 c easily bite into the end plate and the core material 1 of the vertebral body 20. There is an advantage that the relative positional deviation can be prevented more reliably.

  Regarding the thickness of the plate 2 having fine irregularities formed on both the front and back surfaces, the thickness of the minimum thickness portion (the portion between the concave portions on both sides) is 0.3 mm or more, and the maximum thickness portion (the convex portions 2c on both sides) The thickness of the portion between the convex portions 2c is preferably 1.2 mm or less. Thus, the plate 2 having a limited thickness has a strength capable of withstanding the clamping pressure between the upper and lower vertebral bodies 20, 20, and is decomposed and absorbed in about one year at a speed balanced with the growth of the bone tissue. There is an advantage that it can be completely replaced and firmly connected to the vertebral body 20.

  In the biomaterial 11 for artificial cartilage described above, the plates 2 and 2 are laminated on the upper and lower surfaces of the core material 1, and this plate 2 is used for the replacement of the biomaterial for artificial cartilage of the present invention. Corresponding to the type and part, the core material 1 may be laminated only on one side.

  FIG. 5 is a perspective view of a biomaterial for artificial cartilage according to another embodiment of the present invention, and FIG. 6 is a cross section taken along line BB in FIG.

  The biomaterial 12 for artificial cartilage includes the above-described plates 2 and 2 in which the above-described fine irregularities are formed on both the front and back surfaces, and the biodegradable absorbent material 5 is filled in the large and small through holes 2a and 2b. The material 1 is laminated on both upper and lower surfaces of the material 1, and is sewed on the core material 1 so that the peripheral portions of the plates 2 and 2 are put together through the thread 4 through the large and small through holes 2a and 2b located at the peripheral portions of the plates 2 and 2. The pin 3 is omitted.

  When the peripheral portion of the plates 2 and 2 is sewn to the core material 1 with the thread 4 like the biomaterial 12 for artificial cartilage, the core material 1 and the plates 2 and 2 can be omitted even if the pin 3 is omitted. 2 and the plate 2, 2 are not peeled off, and if there are fine irregularities on both the front and back surfaces of the plates 2, 2, Since 2c bites into the end plates of the vertebral bodies 20 and 20, even if the aforementioned pin 3 is omitted, it is possible to prevent the displacement / reversion of the biomaterial 12 for artificial cartilage.

  The yarn 4 is made of a bioinert fiber, a biodegradable fiber, or the like. As the former bioinert, the organic fiber constituting the core material 1 is used, and the latter is biodegradable. As the thread, a fiber made of the above-mentioned lactic acid polymer is used, preferably a thread (monofilament) having a thickness of about 0.2 to 0.3 mm, more preferably a uniaxially stretched thread having a high tensile strength. Is used.

  When such a biomaterial 12 for artificial cartilage is inserted between the upper and lower vertebral bodies as an artificial intervertebral disc, the convex portions 2c on the surfaces of the plates 2 and 2 bite into the end plates of the vertebral bodies 20 and 20 to cause positional deviation / reversion. It is sandwiched between the vertebral bodies 20 and 20 without occurring. As in the case of the biomaterial 11 for artificial cartilage described above, the core material 1 is transformed into a biomimetic and sufficiently functions as an intervertebral disc, and is directly bonded to the upper and lower vertebral bodies without generating fine powder. And sufficient bond fixing force can be obtained.

  In the biomaterial 12 for artificial cartilage, the perforated plate 2 shown in FIG. 7 or the perforated plate 2 shown in FIG. 8 may be used as a plate laminated on both surfaces of the core material 1. The plate 2 shown in FIG. 7 has a plurality of pyramidal or conical protrusions 2d (with a height higher than the fine unevenness on the surface of the perforated plate 2 in which the fine unevenness shown in FIG. Further, the core material 1 is formed by filling the through-hole 2a (2b) of the plate 2 shown in FIG. When the artificial cartilage biomaterial laminated on both sides is inserted between the vertebral bodies, the protrusion 2d deeply bites into the end plate of the vertebral body 20, so that the position of the artificial cartilage biomaterial can be obtained even without the pin 3 described above. There is an advantage that displacement and slippage can be prevented more reliably. Further, the plate 2 shown in FIG. 8 is the same as the perforated plate 2 shown in FIG. 4 except that the surface 2 is formed with unevenness 2e having a sawtooth shape in cross section. The biomaterial for artificial cartilage laminated on both surfaces of the core material 1 so that the slope of the sawtooth-shaped irregularities 2e faces forward (forward in the insertion direction) has little resistance when inserted between the vertebral bodies 20 and 20, and is inserted. Is easy, and has the advantage that it cannot be easily pulled out after insertion. Of course, the plate 2 of FIGS. 7 and 8 may be laminated on both surfaces of the core material 1 of the biomaterial 11 for artificial cartilage described above. In FIG. 7 and FIG. 8, the same reference numerals are given to portions common to the plate 2 of FIG.

  FIG. 9 is a sectional view of a biomaterial for artificial cartilage according to still another embodiment of the present invention.

  The artificial cartilage biomaterial 13 is a coating made of the biodegradable absorbable material having the above-described osteoconductivity and / or osteoinductivity on both the front and back surfaces of the artificial cartilage biomaterial 11 described above. The layers 6 and 6 are laminated, and both ends of each pin 3 are slightly protruded from the surface of the coating layers 6 and 6. The coating layer 6 is not necessarily laminated on both the front and back surfaces of the plate 2 and may be laminated only on the surface of the plate 2.

  The thickness of the covering layer 6 is not particularly limited, but the biodegradable and absorbable material constituting the covering layer 6 is made of a bioceramic powder, cytokine, drug, osteoinductive factor, etc. In the case where it is contained, the thickness is preferably about 0.5 to 2 mm. If the covering layer 6 is thinner than 0.5 mm, the adhesion with the vertebral body 20 due to compressive deformation may be reduced. If the covering layer 6 is thicker than 2 mm, the time required for decomposition and resorption and replacement with bone tissue becomes longer. This causes inconvenience.

  When such a biomaterial for artificial cartilage 13 is inserted between the upper and lower vertebral bodies 20 and 20 as an artificial intervertebral disc, in addition to the action and effect of the biomaterial for artificial cartilage 11 described above, it becomes early as the covering layer 6 is decomposed. Bone tissue is formed almost uniformly on the surface of the plate 2 so as to be bonded to the vertebral body 20. In particular, the coating layer 6 is made of the aforementioned biodegradable polymer porous body, bioceramics powder, cytokine or drug. In the case of containing a bone inducing factor or the like, the coating layer 6 serves as a cushioning material and is brought into close contact with the vertebral body 20 by compressive deformation, so that osteoblasts can easily enter the porous body. Therefore, the conduction formation and / or induction formation of the bone tissue is accelerated, and the vertebral body 20 is joined within a short period of time.

  Next, some embodiments of the biomaterial for artificial cartilage used as the partial replacement type artificial disc will be described.

  The biomaterial 14 for artificial cartilage shown in FIG. 10 is used as a partial replacement type artificial disc for replacing half of the intervertebral disc of the spine (particularly the lumbar vertebra). 11 is divided into left and right parts. The structure of the artificial cartilage biomaterial 14 is the same as that of the artificial cartilage biomaterial 11 described above, and includes a bioactive bioceramics powder on both upper and lower surfaces of the core material 1 made of an organic fiber tissue structure. Plates 2 and 2 made of biodegradable absorbable polymers having large and small through holes 2a and 2b formed in the thickness direction are laminated, and the through holes 2a and 2b are provided with the aforementioned osteoconductivity and / or osteoinductivity. A structure in which the biodegradable bioabsorbable material 5 that is rapidly decomposed is filled and two biodegradable / absorbable pins 3 are vertically penetrated so that both ends of the pins 3 protrude slightly from the surfaces of the plates 2 and 2. It has become.

  Such a partial replacement type biomaterial 14 for artificial cartilage can be inserted into one side between the vertebral bodies 20 and 20 from the back of the lumbar vertebrae. Compared to those inserted between the vertebral bodies from the side, surgery can be performed easily. The artificial cartilage biomaterial 14 inserted between the vertebral bodies has no displacement or slippage, the core material 1 is flexible and has deformation characteristics close to that of the intervertebral disc of the living body, and is directly coupled to the vertebral body 20 for fixing force. And fine powder due to wear does not occur, which is extremely suitable as a partial replacement type artificial disc.

  In this partial replacement type artificial cartilage biomaterial 14, the plate 2 is formed as a forged body, fine irregularities are formed on both surfaces of the plate 2, a plurality of protrusions 2 d are formed on the surface of the plate 2, Needless to say, a coating layer made of the biodegradable absorbent material 5 may be provided on the surface 2 or both of the front and back surfaces, or the peripheral edge of the plate 2 may be sewn with a thread and the pin 3 may be omitted.

  A partial replacement type artificial cartilage biomaterial 15 shown in FIG. 11 is an arc-shaped biomaterial, and one end (tip) thereof is rounded, and a pair of left and right is inserted between vertebral bodies of the spine (particularly the lumbar vertebra). Is. When the artificial cartilage biomaterial 15 is used as an artificial disc for an adult lumbar vertebra, for example, the lateral width is about 9 mm, the thickness is about 11 mm, and the radius of curvature of the arc-shaped center line is as follows. Is about 22 to 23 mm, and the length dimension along the arc-shaped center line is about 30 mm.

  The artificial cartilage biomaterial 15 is different in shape from the total replacement type artificial cartilage biomaterial 11 but has the same structure. That is, a plate made of a biodegradable absorbent polymer containing bioactive bioceramic powder on both upper and lower surfaces of a core material 1 made of an organic fiber tissue structure and having large and small through holes 2a and 2b in the thickness direction. 2 and 2 (a plurality of large through holes 2a on the center line and a plurality of small through holes 2b on the periphery) are stacked, and the osteoconductivity and / or osteoinduction described above is formed in the through holes 2a and 2b. The biodegradable biodegradable absorbent material 5 having the ability to be decomposed is filled, and the three biodegradable absorbable pins 3 are vertically penetrated using the large through-holes 3a on the center line, so that each pin 3 It has a structure in which both ends are slightly protruded from the plates 2 and 2.

  Such a partial replacement type biomaterial for artificial cartilage 15 is inserted from the back of the lumbar vertebrae between the vertebral bodies 20 as shown in FIG. 12, and therefore, compared with a total replacement type biomaterial for artificial cartilage. In addition, since the tip of the artificial cartilage biomaterial 15 is formed in a round shape, the tip can be smoothly inserted without being caught by the vertebral body 20. The biomaterial 15 for artificial cartilage has no displacement or dislocation, the core material 1 is flexible and deforms biomimeticly close to the intervertebral disc of the living body, and is directly coupled to the vertebral body 20 to provide a large fixing force and wear. Since there is no generation of fine powder due to, it can fully serve as an intervertebral disc.

  When the pair of left and right artificial cartilage biomaterials 15 and 15 are inserted between the vertebral bodies 20 as described above, a structure similar to that of the biomaterial 15 is provided in the middle of the left and right artificial cartilage biomaterials 15 and 15. It is preferable to insert a partially-placed slant-shaped artificial cartilage biomaterial 16 comprising

  In the partial replacement type artificial cartilage biomaterials 15 and 16 described above, the plate 2 is formed as a forged body, fine irregularities are formed on both surfaces of the plate 2, and a plurality of protrusions 2 d are formed on the surface of the plate 2. Of course, a coating layer made of the biodegradable absorbent material 5 may be provided on the surface or both front and back surfaces of the plate 2, or the peripheral portion of the plate 2 may be sewn with a thread to omit the pins 3.

  As described above, the present invention has been described with reference to the main embodiments of the biomaterial for artificial cartilage used as the total replacement and partial replacement artificial discs, but the shape and size of the biomaterial for artificial cartilage of the present invention are as follows. Needless to say, it can be appropriately changed according to the insertion site. In addition, if the shape and size of the biomaterial for artificial cartilage of the present invention is changed to a shape similar to a meniscus other than an intervertebral disc or various articular cartilages, it can be used as an artificial meniscus or various articular cartilage. To get.

It is a perspective view of the biomaterial for artificial cartilage which concerns on one Embodiment of this invention. It is the sectional view on the AA line of FIG. It is explanatory drawing of one example of use of the biomaterial for artificial cartilage. It is sectional drawing which shows the other example of the plate used for the biomaterial for artificial cartilage of this invention. It is a perspective view of the biomaterial for artificial cartilage which concerns on other embodiment of this invention. FIG. 6 is a sectional view taken along line B-B in FIG. 5. It is sectional drawing which shows the further another example of the plate used for the biomaterial for artificial cartilage of this invention. It is sectional drawing which shows the further another example of the plate used for the biomaterial for artificial cartilage of this invention. It is sectional drawing of the biomaterial for artificial cartilage which concerns on other embodiment of this invention. It is a perspective view of the biomaterial for artificial cartilage which concerns on other embodiment of this invention. It is a perspective view of the biomaterial for artificial cartilage which concerns on other embodiment of this invention. It is a top view which shows the insertion position of the biomaterial for artificial cartilage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core material 2 Plate 2a, 2b Through-hole 3 Pin 4 Thread 5 Biodegradable absorbable material 6 Coating layer 11, 12, 13, 14, 15, 16 Biomaterial for artificial cartilage 20 Vertebral body

Claims (4)

  A living body containing bioactive bioceramics powder on one or both sides of a core material composed of a multi-axial three-dimensional or three-dimensional woven or comb structure of organic fibers made of organic fibers. A plate made of a degradable and absorbable polymer, which is laminated with a number of through-holes in the thickness direction, and has osteoconductivity and / or osteoinductivity in all or some of the through-holes of this plate. And a biomaterial for artificial cartilage, which is filled with a biodegradable and absorbable material that is faster to decompose in vivo than the plate.   The coating layer made of a biodegradable and absorbable material having osteoconductivity and / or osteoinductivity and faster in vivo degradation than the plate is laminated on the surface or both sides of the plate. The biomaterial for artificial cartilage described.   The biodegradable / absorbable material is a porous body of biodegradable / absorbable polymer having continuous pores therein, bioceramics powder having osteoconductivity, and / or cytokine having osteoinductivity, bone The biomaterial for artificial cartilage according to claim 1 or 2, wherein the biomaterial for artificial cartilage includes at least one of a drug having an inductive ability and an osteoinductive factor.   The biodegradable and absorbable material includes at least one of bioceramics powder having osteoconductivity in collagen and / or cytokine having osteoinductive ability, drug having osteoinductive ability, and osteoinductive factor. The biomaterial for artificial cartilage according to claim 1 or 2, wherein the biomaterial is an artificial cartilage.