JP2019180797A - Vertebral body spacer - Google Patents

Abstract

To provide a vertebral body spacer capable of improving binding performance with organism bones, and surely performing insertion into between vertebral bodies.SOLUTION: A vertebral body spacer 10 is inserted in a prescribed insertion direction F1 into between a first vertebral body and a second vertebral body. The vertebral body spacer 10 comprises a body part 21 having a high polymer material as the main constituent. A hollow part 31 opening on an external surface of the body part 21 is formed in the body part 21, and an inside surface 34 of the hollow part 31 is covered with a porous layer 51. The body part 21 has a tip part 22 positioned at a tip side in the insertion direction F1, a base end part 23 positioned on an opposite side to the tip part 22, and a hole part 71 opening in the base end part 23 and having an inside surface 72 uncovered with the porous layer 51.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a vertebral body spacer that can be replaced with an intervertebral disc in spinal surgery.

  Conventionally, in the treatment of intervertebral disc herniation and spinal canal stenosis, etc., after removing the intervertebral disc of the spine (vertebral column), inserting a vertebral body spacer, which is an implant, into the removed portion, surgical operation to replace the intervertebral disc with a vertebral body spacer has been performed. (For example, refer to Patent Document 1). By performing this operation, it is possible to fix vertebral bodies adjacent to each other via the vertebral body spacers or to improve the wobble of the spinal column. As the polymer material constituting the vertebral body spacer, polyether ether ketone (PEEK) having mechanical properties equivalent to those of cortical bone (living bone) is usually used. Since PEEK has high chemical stability, PEEK does not melt even when embedded in the body.

  However, while the vertebral body spacer is made of the above-described polymer material, the living bone is made of a ceramic material such as hydroxyapatite, so there is no chemical bond between them. In this case, even if the vertebral body spacer is inserted between adjacent vertebral bodies, the weight (load) applied to the vertebral body acts in the direction of pushing out the vertebral body spacer, and the vertebral body spacer is pushed out between the vertebral bodies (so-called phenomenon) May occur.

  Therefore, for example, it is conceivable to form a porous layer as shown in Patent Document 2 on the surface of the vertebral body spacer. In this way, the bone tissue of the living bone (vertebral body, etc.) enters into the open pores of the porous layer after the operation, so that the living bone and the vertebral body spacer can be obtained by the anchor effect obtained by the open pores. It is possible to improve the connectivity.

JP-A-2006-135243 (FIG. 1 etc.) JP 2014-132944 A (FIGS. 2 to 4 etc.)

  By the way, the base end portion of the vertebral body spacer is provided with a hole to which an insertion instrument used for insertion of the vertebral body spacer between the vertebral bodies can be attached. The vertebral body spacer is inserted between the vertebral bodies by pressing the insertion instrument with the insertion instrument attached to the hole, and the vertebral body spacer is inserted between the vertebral bodies by removing the insertion instrument after the vertebral body spacer is inserted. Only comes to be placed.

  However, since the porous layer described in Patent Document 2 is formed by immersing the vertebral body spacer in concentrated sulfuric acid or the like, not only the outer surface of the vertebral body spacer but also the inner surface of the hole is porous. It will be covered with layers. Since the porous layer has open pores and is relatively low in strength, even if an insertion device is attached to the hole whose inner surface is covered with the porous layer, there is a possibility that sufficient attachment strength cannot be ensured. is there. In this case, when the vertebral body spacer is inserted, wobbling or loosening of the insertion instrument is likely to occur, and there is a problem that the vertebral body spacer cannot be inserted well between the vertebral bodies. In some cases, the insertion tool may come off.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a vertebral body spacer that can improve the connectivity with living bones and can be reliably inserted between vertebral bodies. Is to provide.

  As a means (means 1) for solving the above-mentioned problem, an intervertebral disk between a first vertebral body and a second vertebral body adjacent to the first vertebral body is inserted and arranged in a predetermined insertion direction. The vertebral body spacer includes a main body portion mainly composed of a polymer material, and a hollow portion that opens at an outer surface of the main body portion is formed in the main body portion, and the hollow portion An inner surface of the main body is covered with a porous layer, and the main body includes a distal end located on the distal end side in the insertion direction, a proximal end located on the opposite side of the distal end, and the proximal end There is a vertebral body spacer characterized by having a hole portion that is open and has an inner surface that is not covered with the porous layer.

  Therefore, in the invention described in the means 1, the inner surface of the hollow portion formed in the main body is covered with the porous layer. In this case, after the operation, a living tissue such as a bone tissue of a living bone (first vertebral body, second vertebral body, etc.) enters the hollow portion and enters a porous layer covering the inner surface of the hollow portion. As a result, the connectivity between the living bone and the vertebral body spacer can be improved. On the other hand, the inner surface of the hole opening at the base end of the main body is not covered with the porous layer. Since the porous layer has open pores and is relatively low in strength, it is not covered by the porous layer, and the dense and relatively strong main body is exposed on the inner surface. When the insertion tool is attached to the hole portion, sufficient attachment strength can be ensured. As a result, since the wobbling and loosening of the insertion instrument is prevented, the vertebral body spacer can be reliably inserted between the first vertebral body and the second vertebral body.

  The vertebral body spacer includes a main body mainly composed of a polymer material. The polymer material constituting the main body may be a known biocompatible material, specifically, a material that can be adapted to the first vertebral body and the second vertebral body. For example, as a polymer material constituting the main body, polyamide (PA), polyacetal (POM), polycarbonate (PC), polyphenylene ether (PPE), modified polyphenylene ether (m-PPE), polyphenylene oxide (PPO), poly Butylene terephthalate (PBT), polyethylene terephthalate (PET), polysulfone (PSU), syndiotactic polystyrene (SPS), polyethersulfone (PES), polyphenylene sulfide (PPS), polyarylate (PAR), polyetherimide (PEI) , Polyetheretherketone (PEEK), polyamideimide (PAI), polyimide (PI), polytetrafluoroethylene (PTFE), ethylene vinyl alcohol copolymer resin (EVO) ), Polymethylpentene (PMP), and engineering plastics such as diallyl phthalate resin (DAP) and the like. The polymer material is preferably a polyether ether ketone having mechanical properties equivalent to those of living bones and high biocompatibility.

  The polymer material may include, for example, carbon fibers including carbon nanotubes, glass fibers, ceramic fibers, metal fibers, organic fibers, and the like. In this way, the strength of the main body can be improved. Examples of the glass fiber include a fibrous material of borosilicate glass (E glass), a fibrous material of high strength glass (S glass), and a fibrous material of high elasticity glass (YM-31A). Ceramic fibers include silicon carbide fiber, silicon nitride fiber, alumina fiber, potassium titanate fiber, boron carbide fiber, magnesium oxide fiber, oxide Examples include zinc fibrous materials, aluminum borate fibrous materials, and boron fibrous materials. Further, examples of the metal fiber include tungsten fiber, molybdenum fiber, stainless steel fiber, steel fiber, and tantalum fiber. Examples of the organic fiber include a polyvinyl alcohol fiber, a polyamide fiber, a polyethylene terephthalate fiber, a polyester fiber, and an aramid fiber.

  In addition, when the polymer material includes the above fiber, the polymer material includes polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), and ethylene-vinyl acetate copolymer in addition to the engineering plastic described above. Resin (EVA), ethylene-ethyl acrylate copolymer resin (EEA), 4-methylpentene-1 resin, ABS resin, AS resin, ACS resin, ethylene vinyl chloride copolymer resin, propylene vinyl chloride copolymer resin, vinylidene chloride ( VDC), polyvinyl alcohol (PVA), polyvinyl formal, polyvinyl acetoacetal, polyfluorinated ethylene propylene (PFEP), poly (trifluoroethylene chloride) (PTFCCE), polymethyl methacrylate (PMMA), polyallyl ether ketone (PAEK), Polyketo Sulfide, polystyrene (PS), isophthalic acid-based resin, polyurethane (PUR), may be mentioned alkylbenzenes, poly ether and the like.

  In the vertebral body spacer, the inner surface of the hollow portion opened on the outer surface of the main body is covered with the porous layer. Here, the porous layer is preferably formed using a polymer material constituting the main body. In this case, since the main body portion and the porous layer are integrally formed of the same polymer material, the strength of the vertebral body spacer is improved and it is difficult to break.

  Furthermore, the porous layer preferably has open pores that open on its surface. In such a case, since the living tissue such as the bone tissue of the living bone enters the open pores of the porous layer after the operation, the living bone and the vertebral body spacer are caused by the anchor effect obtained by the open pores. It is possible to improve the connectivity. The porous layer preferably has a bioactive substance on at least one of the inner surface of the open pores and the surface of the porous layer. In this case, after the vertebral body spacer is inserted between the first vertebral body and the second vertebral body, a chemical reaction between the bioactive substance and the bone tissue of the living bone begins, and a new living bone Will be formed promptly. As a result, the physical coupling force between the living bone and the vertebral body spacer can be exhibited at an early stage.

Here, the bioactive substance is not particularly limited as long as it has a high affinity with a living body and chemically reacts with a living tissue such as bone tissue, and examples thereof include calcium phosphate compounds, bioactive glass, and calcium carbonate. Can be mentioned. Examples of calcium phosphate compounds include calcium hydrogen phosphate, calcium hydrogen phosphate hydrate, calcium dihydrogen phosphate, calcium dihydrogen phosphate hydrate, α-type tricalcium phosphate, β-type tricalcium phosphate, and dolomite. , Tetracalcium phosphate, octacalcium phosphate, hydroxyapatite, fluorapatite, carbonate apatite, chlorapatite and the like. Examples of the bioactive glass include bioglass and crystallized glass (also referred to as “glass ceramic”). Examples of bioglass include SiO ₂ —CaO—N ₂ O—P ₂ O ₅ glass, SiO ₂ —CaO—Na ₂ O—P ₂ O ₅ —K ₂ O—MgO glass, SiO ₂ —CaO—Al _2. Examples thereof include O ₃ —P ₂ O ₅ glass, and examples of the crystallized glass include SiO ₂ —CaO—MgO—P ₂ O ₅ glass (also referred to as “apatite wollastonite crystallized glass”) and CaO—. Examples include Al ₂ O ₃ —P ₂ O ₅ glass.

  In addition, it is preferable that a bioactive substance is at least 1 sort (s) of a calcium phosphate compound and bioactive glass at the point that it is excellent in bioactivity. In addition, calcium phosphate compounds are hydroxyapatite or tricalcium phosphate in that they are similar in composition, structure and properties to living bones, have excellent stability in the body environment and do not show significant solubility in the body. It is preferable.

In this embodiment, explanatory drawing which shows the state by which the vertebral body spacer was inserted between the 1st vertebral body and the 2nd vertebral body. The perspective view which shows the vertebral body spacer when it sees from the front-end | tip part side. The perspective view which shows the vertebral body spacer when it sees from the base end part side. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. The principal part sectional view showing a porous layer.

  Hereinafter, an embodiment embodying the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the vertebral body spacer 10 according to the present embodiment is an implant that substitutes for the removed intervertebral disc when the intervertebral disc to be affected is removed from the spinal column and then inserted into the removed portion. Specifically, the vertebral body spacer 10 is inserted along the predetermined insertion direction F1 with respect to the removal portion between the adjacent first vertebral body 11 and the second vertebral body 12, thereby removing the removal portion. Is to be arranged.

  As shown in FIGS. 1 to 4, the vertebral body spacer 10 includes a main body 21 mainly composed of a polymer material (polyetheretherketone (PEEK) in the present embodiment). The main body 21 has a distal end portion 22 located on the distal end side in the insertion direction F1 and a proximal end portion 23 located on the proximal end side in the insertion direction F1 (that is, opposite to the distal end portion 22). Yes. Furthermore, the outer surface of the main body 21 includes a first surface 24 that contacts the first vertebral body 11, a second surface 25 that contacts the second vertebral body 12, and a pair of side surfaces 26. The core member 20 may be embedded in the main body 21. The core member 20 is formed in a rod shape using a material reflected in an X-ray image when X-rays are irradiated, and extends in a direction F2 (see FIGS. 2 and 3) orthogonal to the insertion direction F1. The core member 20 is for confirming the position of the vertebral body spacer 10 when inserted between the vertebral bodies 11 and 12 by an X-ray image. In addition, as a forming material of the core material 20, metals, such as stainless steel, titanium, a titanium alloy, and a tantalum, barium sulfate, a zirconium dioxide, etc. are mentioned. Moreover, although the core material 20 shown by FIGS. 1-4 is embed | buried under the front-end | tip part 22 of the main-body part 21, it may be embed | buried under the base end part 23 side. Further, the core member 20 has a rod shape, but may have another shape such as a spherical shape.

  As shown in FIGS. 1 to 4, a hollow portion 31 that opens on the outer surface of the main body portion 21 is formed in the main body portion 21. Specifically, as shown in FIG. 4, the hollow portion 31 has a first opening portion 32 (in FIGS. 2 and 3) that opens at the central portion of the first surface 24 and the central portion of the second surface 25. (Not shown). Moreover, as FIG. 1-4 shows, the hollow part 31 is provided with the 2nd opening part 33 opened in the area | region near the front-end | tip part 22 in a pair of side surface 26. As shown in FIG. The 1st opening part 32 and the 2nd opening part 33 have comprised the ellipse shape long in the insertion direction F1.

  Concavities and convexities 41 are respectively formed on the first surface 24 and the second surface 25 of the main body 21. The unevenness 41 is configured by arranging a plurality of convex portions 42 extending in the direction F2 (see FIGS. 2 and 3) perpendicular to the insertion direction F1 along the insertion direction F1. The convex portion 42 constituting the unevenness 41 on the first surface 24 side is a portion that becomes a contact portion with the first vertebral body 11 when the vertebral body spacer 10 is inserted between the vertebral bodies 11 and 12, and is on the second surface 25 side. The convex portion 42 constituting the concave and convex portion 41 is a portion that becomes a contact portion with the second vertebral body 12 when the vertebral body spacer 10 is inserted between the vertebral bodies 11 and 12.

  As shown in FIG. 4, the entire outer surface of the main body 21 including the first surface 24, the second surface 25, and the side surface 26 is covered with a porous layer 51. Specifically, the porous layer 51 covering the first surface 24 includes a surface of the unevenness 41 (convex portion 42) formed on the first surface 24 and a region where the unevenness 41 is not formed on the first surface 24. Covering. Similarly, the porous layer 51 covering the second surface 25 covers the surface of the unevenness 41 (convex portion 42) formed on the second surface 25 and the region where the unevenness 41 is not formed on the second surface 25. ing. In the present embodiment, the entire inner side surface 34 of the hollow portion 31 is also covered with the porous layer 51. In addition, the porous layer 51 of this embodiment is a layer formed integrally with the main body portion 21 using a polymer material (PEEK) constituting the main body portion 21.

  The thickness of the porous layer 51 is preferably 10 μm or more and 500 μm or less, more preferably 20 μm or more and 300 μm or less, and particularly preferably 30 μm or more and 200 μm or less. In addition, the thickness of the porous layer 51 can be measured by burying the main body portion 21 provided with the porous layer 51 in an epoxy resin and curing it, and performing cross-sectional observation after polishing.

  As shown in FIG. 5, the porous layer 51 has a plurality of open pores 53 that open at its surface 52. The average value of the pore diameter of each open pore 53 is 3 μm or more and 300 μm or less. Further, the porous layer 51 has a bioactive substance 61 on the inner surface 54 of the open pores 53 and the surface 52 of the porous layer 51. In addition, the bioactive substance 61 of this embodiment is a hydroxyapatite (calcium phosphate compound).

  Here, the state of the bioactive substance 61 is preferably a state that can be supported on the inner surface 54 of the open pores 53 and the surface 52 of the porous layer 51, and specifically, granular, granular, powdery, etc. Can be mentioned. In addition, examples of the shape of the bioactive substance 61 include a spherical shape, an elliptical shape, a needle shape, a rod shape, a plate shape, and a polygonal shape. The particle size of the bioactive substance 61 is 0.001 μm or more and 10 μm or less.

  As shown in FIGS. 3 and 4, the main body 21 has a screw hole 71 that extends along the insertion direction F <b> 1 and opens at the proximal end 23. The insertion device 81 is attached to the vertebral body spacer 10 by screwing the screw portion 82 (see FIG. 4) of the insertion device 81 used for the insertion of the vertebral body spacer 10 into the screw hole portion 71. Become. The inner side surface 72 of the screw hole portion 71 is not covered with the porous layer 51 described above, and the main body portion 21 that is dense and has a relatively high strength is exposed.

  Further, as shown in FIG. 1 to FIG. 3, groove portions 91 that open at the side surface 26 are provided in regions near the base end portion 23 of the pair of side surfaces 26 of the main body portion 21. Both the groove portions 91 are extended along the insertion direction F <b> 1, the proximal end side opens at the proximal end surface 27 of the main body portion 21, and the distal end side communicates with the second opening portion 33. The width of the groove 91 is equal to the width of the second opening 33 (that is, the length in the thickness direction of the vertebral body spacer 10). Then, when the insertion instrument 81 is attached to the vertebral body spacer 10, a pair of arms 83 (see FIG. 3) provided in the insertion instrument 81 is inserted into the groove 91.

  Next, a method for using the vertebral body spacer 10 will be described.

  First, a surgical operation is performed to remove an intervertebral disc as an affected part from the spinal column, and a vertebral body spacer 10 is inserted into the resulting removed part (see FIG. 1). Specifically, first, the screw portion 82 of the insertion instrument 81 is screwed into the screw hole portion 71 provided in the base end portion 23 of the main body portion 21 (see FIG. 4). Next, the pair of arm portions 83 provided in the insertion instrument 81 are inserted into the pair of groove portions 91 formed in the main body portion 21 (see FIG. 3). As a result, the insertion instrument 81 is attached to the vertebral body spacer 10.

  Next, the vertebral body spacer 10 is inserted between the first vertebral body 11 and the second vertebral body 12 by moving the insertion instrument 81 in the insertion direction F1. At this time, the vertebral body spacer 10 is inserted so that the pair of side surfaces 26 of the main body 24 face the vertebral bodies 11 and 12. Then, by rotating the insertion instrument 81 (and the vertebral body spacer 10) clockwise or counterclockwise, the unevenness 41 formed on the first surface 24 is brought into contact with the first vertebral body 11, and the first The irregularities 41 formed on the two surfaces 25 are brought into contact with the second vertebral body 12. Then, after removing the arm portion 83 of the insertion instrument 81 from the groove 91 and then removing the screw portion 82 of the insertion instrument 81 from the screw hole 71, only the vertebral body spacer 10 remains between the vertebral bodies 11 and 12. .

  After the surgical operation is completed, bone tissue of living bones (vertebral bodies 11, 12, etc.) gradually grows, and the grown bone tissue is an open pore of the porous layer 51 that covers the outer surface of the main body 21. Enter 53. A part of the grown bone tissue enters the hollow portion 31 from the first opening portion 32 and the second opening portion 33 and enters the open pores 53 of the porous layer 51 covering the inner side surface 34 of the hollow portion 31. enter in. As a result, the connectivity between the living bone and the vertebral body spacer 10 is improved.

  Next, a method for manufacturing the vertebral body spacer 10 will be described.

  First, a 1st process is performed and the molded object used as the vertebral body spacer 10 (main-body part 21) is formed using a polymer material (PEEK in this embodiment). In addition, although the formation method of a molded object is not necessarily limited, For example, the method of forming a molded object by cutting the cylindrical body etc. which were obtained by extrusion molding etc., and the metal mold | die were used. The method etc. which form a molded object by injection molding can be mentioned.

  In the subsequent second step, the porous layer 51 having a large number of open pores 53 is formed on the surface of the molded body (specifically, the outer surface of the main body 21 and the inner surface 34 of the hollow portion 31). Form. Here, as a method of forming the open pores 53, for example, the molded body is immersed in a corrosive liquid such as concentrated sulfuric acid, concentrated nitric acid, chromic acid, and then molded into a cleaning liquid (for example, pure water) from which the polymer material does not elute. The method of immersing a body can be mentioned. In the present embodiment in which the polymer material constituting the molded body is polyetheretherketone (PEEK), the molded body is immersed in concentrated sulfuric acid, and then the molded body is immersed in pure water, whereby open pores 53 are obtained. Can be formed.

  In the subsequent third step, the obtained porous layer 51 is loaded with a bioactive substance 61 (calcium phosphate compound). As a result, the vertebral body spacer 10 in which the bioactive substance 61 is supported on the inner surface 54 of the open pore 53 and the surface 52 of the porous layer 51 can be obtained (see FIG. 5). In addition, as a method of supporting the bioactive substance 61, a liquid phase method in which the molded body in which the porous layer 51 is formed is immersed in both a solution containing calcium ions and a solution containing phosphate ions, Examples of the method include a dipping method in which the molded body on which the porous layer 51 is formed is dipped in a suspension containing a large amount of the bioactive substance 61 and then dried. The medium in which the bioactive substance 61 is suspended is not particularly limited as long as it does not dissolve the polymer material. For example, alcohol such as methanol, ethanol, propanol, water, acetone, hexane, etc. Can be mentioned.

  In addition, the 2nd process and 3rd process of this embodiment have the shape and magnitude | size similar to the screw part which has the shape and magnitude | size similar to the screw part 82 of the insertion instrument 81, and the arm part 83 of the insertion instrument 81. A jig (not shown) having an arm portion is prepared, and the screw portion of the jig is inserted into the screw hole portion 71. As a result, after the formation of the porous layer 51, the inner side surface 72 of the screw hole portion 71 is not covered with the porous layer 51.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) In the vertebral body spacer 10 of the present embodiment, the inner surface 34 of the hollow portion 31 formed in the main body portion 21 is covered with the porous layer 51. In this case, after surgery, bone tissue of a living bone (vertebral bodies 11, 12, etc.) enters the hollow portion 31 and enters the open pores 53 of the porous layer 51 covering the inner side surface 34 of the hollow portion 31. Therefore, the connectivity between the living bone and the vertebral body spacer 10 can be improved. On the other hand, the inner side surface 72 of the screw hole portion 71 opened at the base end portion 23 of the main body portion 21 is not covered with the porous layer 51. Since the porous layer 51 has the open pores 53, it has a relatively low strength. For this reason, in the present embodiment in which the screw portion 82 of the insertion instrument 81 is screwed into the screw hole portion 71 where the main body 21 having a relatively high strength is exposed without being covered with the porous layer 51, A sufficient mounting strength can be secured. As a result, since the wobbling and loosening of the insertion instrument 81 are prevented, the vertebral body spacer 10 can be reliably inserted between the vertebral bodies 11 and 12. When the inner surface 72 of the screw hole 71 is covered with the porous layer 51, the porous layer 51 is peeled off as the screw portion 82 is screwed, and the peeled porous layer 51 is removed from the main body 21. There is a risk of being released to the outside. However, in the present embodiment in which the inner surface 72 is not covered with the porous layer 51, the porous layer 51 will not be peeled even if the screw portion 82 is screwed. The problem of release itself does not occur.

  (2) In the present embodiment, the screw portion 82 of the insertion instrument 81 is screwed into the screw hole portion 71 extending along the insertion direction F1 in the main body portion 21 to be inserted into the vertebral body spacer 10. An instrument 81 is attached. However, if the screw portion 82 is simply screwed into the screw hole portion 71, there is a problem that the insertion instrument 81 is wobbled in a direction orthogonal to the insertion direction F1. Therefore, in the present embodiment, the arm portion 83 of the insertion instrument 81 is inserted into the groove portion 91 extending along the insertion direction F1 in the main body portion 21. In this case, since the side end surface of the arm part 83 contacts the inner side surface of the groove part 91, the wobbling of the insertion instrument 81 is surely prevented, so that sufficient mounting strength can be ensured.

  (3) In the vertebral body spacer 10 of this embodiment, since the main body portion 21 (and the porous layer 51) is formed of a polymer material, metal allergy can be avoided.

  In addition, you may change the said embodiment as follows.

  In the main body portion 21 of the above-described embodiment, the screw hole portion 71 into which the screw portion 82 of the insertion instrument 81 is screwed is used as the “hole portion”. It may be used as For example, a concave portion into which a convex portion provided in the insertion instrument is fitted may be used as the “hole portion”. The convex portion has a cylindrical shape. The recess has a circular cross section and is provided in the main body. In this case, the insertion device can be attached to the vertebral body spacer by pressing the convex portion into the concave portion.

  In the above embodiment, the entire outer surface of the main body portion 21 and the entire inner side surface 34 of the hollow portion 31 are covered with the porous layer 51. However, only the inner surface 34 of the hollow portion 31 may be covered with the porous layer 51.

  -Although the porous layer 51 of the said embodiment was integrally formed with the main-body part 21 using the polymeric material (PEEK) which comprises the main-body part 21, it is formed separately from the main-body part 21. Also good. For example, a sheet-like porous layer may be attached to the main body portion 21. When the porous layer is formed separately from the main body portion 21, the porous layer may be formed using a material different from the material constituting the main body portion 21.

  -The hollow part 31 of the said embodiment is provided with the 1st opening part 32 opened in the center part of the 1st surface 24 and the 2nd surface 25, and the 2nd opening part 33 opened in a pair of side surface 26. It was. However, the hollow portion 31 may include only the second opening 33 or may include only the first opening 32. Moreover, although the 1st opening part 32 and the 2nd opening part 33 of the said embodiment comprised oval shape, they comprised other shapes, such as circular shape, an ellipse shape, a rectangular shape, and a hexagon shape. Also good.

  The porous layer 51 of the above embodiment has the bioactive substance 61 on both the inner surface 54 of the open pores 53 and the surface 52 of the porous layer 51. However, the porous layer 51 may have the bioactive substance 61 on only one of the inner surface 54 of the open pores 53 and the surface 52 of the porous layer 51, or the bioactive substance 61 itself. It does not have to be.

  In the above embodiment, the unevenness 41 is formed on both the first surface 24 and the second surface 25 of the main body 21. However, the unevenness 41 may be formed on only one of the first surface 24 and the second surface 25 or may not be formed on either the first surface 24 or the second surface 25. Further, the shape of the irregularities 41 (substantially square shape, substantially semicircular shape, etc.), size (height, width), and arrangement mode (the convex portions 42 are arranged along the direction F2 orthogonal to the insertion direction F1) Etc. may be appropriately changed.

  In the above embodiment, the second step of forming the porous layer 51 (open pores 53) and the third step of supporting the bioactive substance 61 on the porous layer 51 include a jig (not shown) in the screw hole portion 71. (Omitted) with the screw part inserted. However, you may perform a 2nd process and a 3rd process in the state which masked the inner surface 72 of the screw hole part 71. FIG. Even in this case, after the formation of the porous layer 51, the inner surface 72 of the screw hole portion 71 is not covered with the porous layer 51. Instead of masking the inner surface 72 of the screw hole portion 71, the second step and the third step are performed with the opening of the screw hole portion 71 (the opening on the base end portion 23 side) closed with a masking tape or the like. Also good. Moreover, you may perform only the 2nd process in the state which attached the jig | tool or masked etc. among the 2nd process and the 3rd process mentioned above.

  -The screw hole part 71 of the said embodiment was a non-through-hole opened only in the base end surface 27 (base end part 23 side). However, the screw hole portion 71 may be a through hole that opens at both the base end surface 27 and the inner side surface 34 of the hollow portion 31.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiment described above are listed below.

  (1) In the means 1, the vertebral body is characterized in that the hollow portion includes a first opening opening on the first surface and the second surface and a second opening opening on the side surface. Spacer.

  (2) In the means 1, the main body portion includes a first surface that contacts the first vertebral body, a second surface that contacts the second vertebral body, and a pair of side surfaces, and the first surface The vertebral body spacer is characterized in that the entire outer surface of the main body including the second surface and the side surface is covered with the porous layer.

  (3) In the technical idea (2), the vertebral body is characterized in that at least one of the first surface and the second surface is uneven, and the surface of the unevenness is covered with the porous layer. Spacer.

  (4) In the above means 1, the vertebral body spacer is inserted between the first vertebral body and the second vertebral body in a state where an insertion device is attached to the main body. Feature vertebral body spacer.

DESCRIPTION OF SYMBOLS 10 ... Vertebral body spacer 11 ... 1st vertebral body 12 ... 2nd vertebral body 21 ... main-body part 22 ... front-end | tip part 23 ... base-end part 26 ... side-surface 31 of main-body part ... hollow part 34 ... inner side surface 51 of hollow part ... porous Surface layer 53 ... Porous layer surface 53 ... Open pores 54 ... Inside surface 61 of the open pores ... Bioactive substance 71 ... Screw hole portion 72 as a hole portion ... Inside surface F1 of the hole portion ... Insertion direction

Claims (7)

A vertebral body spacer inserted and arranged in a predetermined insertion direction at an intervertebral disc between a first vertebral body and a second vertebral body adjacent to the first vertebral body,
The vertebral body spacer includes a main body mainly composed of a polymer material,
In the main body part, a hollow part is formed that opens at the outer surface of the main body part,
The inner surface of the hollow portion is covered with a porous layer;
The main body includes a distal end located on the distal end side in the insertion direction, a proximal end located on the opposite side of the distal end, an opening at the proximal end, and an inner surface in the porous layer. A vertebral body spacer having an uncovered hole.   The vertebral body spacer according to claim 1, wherein the porous layer is formed using the polymer material constituting the main body.   The porous layer has open pores that open on its own surface, and has a bioactive substance on at least one of the inner surface of the open pores and the surface of the porous layer. The vertebral body spacer according to 1 or 2.   The vertebral body spacer according to claim 3, wherein the bioactive substance is a calcium phosphate compound.   The vertebral body spacer according to claim 4, wherein the calcium phosphate compound is hydroxyapatite.   The vertebral body spacer according to claim 1, wherein the polymer material is polyetheretherketone.   The vertebral body spacer according to any one of claims 1 to 6, wherein the polymer material includes carbon fibers.

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