JP2018000548A - Vertebral body spacer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve bondability with a bone tissue in an initial arrangement in a vertebral body spacer and improve long-term stability of a location of the vertebral body spacer.SOLUTION: A vertebral body spacer includes first projection parts and second projection parts. Each first projection part includes: a first crown part forming an angle; and a first plane part located at a first surface side with respect to the first crown part and extending in a direction along the first surface. Each second projection part includes: a second crown part forming an angle; and a second plane part located at a second surface side with respect to the second crown part and extending in the direction along the second surface. The first projection parts and the second projection parts include respectively, porous layers on the surfaces.SELECTED DRAWING: Figure 3

Description

  The present invention relates to vertebral body spacer technology.

  Conventionally, when an intervertebral disc located between two adjacent vertebral bodies is damaged and its original function is impaired, for example, a vertebral body spacer disposed between the two adjacent vertebral bodies is used instead of the intervertebral disc. Known (for example, Patent Document 1).

Japanese Patent No. 3557432 Japanese Patent No. 5404165 International Publication No. 2007/105600

  In the conventional technique, the vertebral body spacer has a concavo-convex structure on the surface so as to bite into the vertebral bodies when being arranged between the vertebral bodies (for example, Patent Document 1). In addition, there is a biological implant having a porous layer formed on the surface in order to bond with bone (for example, Patent Documents 2 and 3). However, in these conventional techniques, further improvement of the connectivity with the vertebral body in the initial stage (initial stage of placement) of the vertebral body spacer and the long-term stability of the placement position of the vertebral body spacer Further improvement of the vertebral body spacer, such as improvement of the vertebral body, is desired. The following various problems can be reduced by improving the connectivity with the vertebral body at the initial stage of placement and improving the long-term stability of the vertebral body spacer. For example, it is possible to reduce the possibility of dislocation, which is a phenomenon in which the vertebral body spacer is detached from the vertebral body, or dislocation, which is a phenomenon that deviates from the original arrangement position.

  The present invention has been made to solve the above-described problems, and can be realized as the following forms or application examples.

(1) According to one aspect of the present invention, a vertebral body spacer for disposing between adjacent vertebral bodies having a first surface and a second surface located on the opposite side of the first surface. Is provided. The vertebral body spacer includes a first protrusion protruding from the first surface and a second protrusion protruding from the second surface, and the first protrusion includes a first apex that forms a corner; A first flat surface portion located on the first surface side of the first top portion and extending in a direction along the first surface, wherein the second protrusion portion forms a corner. And a second flat surface portion that is located on the second surface side of the second top portion and extends in a direction along the second surface, and the first protrusion and the second protrusion are Each has a porous layer on the surface.
According to this aspect, the first protrusion has the first plane part, and the second protrusion has the second plane part. Moreover, the 1st protrusion part containing a 1st plane part and the 2nd protrusion part containing a 2nd plane part each have a porous layer on the surface. Thereby, compared with the case where the first protrusion and the second protrusion do not have a flat surface, a predetermined interval (for example, a cell size interval that contributes to bone formation) is provided with respect to the vertebral bodies facing each other. More porous layers can be placed at different positions. Thereby, when the vertebral body spacer is arranged between the two vertebral bodies, more of the bone tissue of the vertebral body can be received in the porous layer earlier after the arrangement. Therefore, the connectivity between the vertebral body and the vertebral body spacer can be improved. Moreover, since the connectivity between the vertebral body and the vertebral body spacer can be improved earlier, the possibility that the vertebral body spacer is displaced from the original arrangement position can be reduced. That is, the stability of the long-term position of the vertebral body spacer can be improved.

(2) In the above aspect, the first protrusion extends in one direction along the first surface, the second protrusion extends in one direction along the second surface, and the first protrusion The protrusion further includes a first recess formed at a position different from the first top in one direction along the first surface, and the second protrusion is further formed on the second surface. A second concave portion formed at a position different from the second top portion in one direction along the first flat portion, the first flat portion being formed by a bottom surface of the first concave portion, and the second flat portion being It may be formed by the bottom surface of the second recess. According to this aspect, the first plane portion and the second plane portion can be easily formed by the bottom surfaces of the first recess and the second recess.

(3) It is the said form, Comprising: You may have the 1st through-hole penetrated over the said 1st surface and the said 2nd surface. According to this aspect, when the bone tissue of the vertebral body facing the first surface or the second surface grows, the grown bone tissue can be received by the first through hole. The bondability can be further improved.

(4) It is the said form, Comprising: Even if it has the 2nd through-hole which further connects the side surface which connects the said 1st surface and the said 2nd surface, and the said side surface and the said 1st through-hole Good. According to this aspect, when the bone tissue of the vertebral body grows to a position facing the side surface, the grown bone tissue can be received by the second through-hole, so that the connectivity between the vertebral body and the vertebral body spacer is improved. It can be further improved.

(5) It is the said form, Comprising: The said 1st protrusion part is a height position different from a said 1st plane part on the basis of the said 1st surface, and the said 1st surface rather than the said 1st top part. It may be a first sub-plane portion formed at a position on the side and extending in a direction along the first surface. Here, the vertebral body spacer receives a load from the vertebral bodies when arranged between the vertebral bodies. This load varies for each patient using the vertebral body spacer. Due to this load, a part of the first protrusion (first apex) of the vertebral body spacer is crushed or a part of the vertebral body is buried in the vertebral body. The distance of changes. According to the said form, in addition to a 1st plane part, a 1st protrusion part has a 1st subplane part arrange | positioned in a different height position, By corresponding to said distance which changes for every patient, A plane part (first plane part or first sub-plane part) having a predetermined interval with respect to the vertebral body can be provided.

(6) It is the said form, Comprising: The said 2nd protrusion part is a said 2nd surface rather than the said 2nd surface from the height position different from a said 2nd plane part on the basis of the said 2nd surface. It may be a second sub-plane portion formed at a position on the side and extends in a direction along the second surface. Here, the vertebral body spacer receives a load from the vertebral bodies when arranged between the vertebral bodies. This load varies for each patient using the vertebral body spacer. Due to this load, a part of the second protrusion (second apex) of the vertebral body spacer is crushed or a part is buried in the vertebral body, so that the vertebral body facing the second surface and the second surface The distance of changes. According to the said form, in addition to a 2nd plane part, a 2nd protrusion part has the 2nd sub plane part arrange | positioned in a different height position, By corresponding to said distance which changes for every patient, A plane part (second plane part or second sub-plane part) having a predetermined interval with respect to the vertebral body can be provided.

(7) In the above embodiment, the vertebral body spacer may be made of a material mainly composed of a polymer material. According to this embodiment, the vertebral body spacer can be produced using a material mainly composed of a polymer material.

(8) In the above embodiment, the polymer material may be a material selected from the group consisting of polyether ether ketone, a resin including carbon fiber and polyether ether ketone. In general, polyetheretherketone is biocompatible and has mechanical properties similar to bone. According to this embodiment, the polymer material is a material selected from the group consisting of polyether ether ketone and a resin including carbon fiber and polyether ether ketone, so that the connectivity between the vertebral body and the vertebral body spacer Can be further improved.

(9) It is the said form, Comprising: The said porous layer may be formed in the whole surface of the said vertebral body spacer. According to this embodiment, when the bone tissue of the vertebral body grows, more bone tissue can be received in the porous layer, so that the connectivity between the vertebral body and the vertebral body spacer can be further improved.

(10) It is the said form, Comprising: The said porous layer may have a bioactive substance. According to this embodiment, when a vertebral body spacer is arranged between vertebral bodies, a chemical reaction between the bioactive substance and the bone tissue starts, and new bone can be rapidly formed. Thereby, a vertebral body and a vertebral body spacer can be combined at an earlier stage.

(11) In the above form, the bioactive substance may be calcium phosphate. According to this embodiment, calcium phosphate can be used as the bioactive substance.

(12) It is the said form, Comprising: Hydroxyapatite may be sufficient as the said calcium phosphate. According to this embodiment, hydroxyapatite can be used as calcium phosphate.

  It should be noted that the present invention can be realized in various forms, and in addition to the vertebral body spacer, for example, can be realized in an aspect such as a vertebral body spacer manufacturing method.

It is a 1st figure for demonstrating the usage example of the vertebral body spacer as 1st Embodiment. It is the figure which looked at the figure shown in FIG. 1 from the paper surface upper side. It is a 1st perspective view of a vertebral body spacer. It is a 2nd perspective view of a vertebral body spacer. It is a perspective view which shows a part of 1st surface side of a vertebral body spacer. It is F5A-F5A sectional drawing of FIG. It is F5B-F5B sectional drawing of FIG. It is a perspective view which shows a part of 2nd surface side of a vertebral body spacer. It is a processing flow which shows the manufacturing process of a vertebral body spacer. It is the figure which looked at the vertebral body spacer as 2nd Embodiment from the 1st surface side. It is F10-F10 sectional drawing of FIG. It is a figure for demonstrating the vertebral body spacer of a 1st modification.

A. First embodiment:
FIG. 1 is a first diagram for explaining an example of use of a vertebral body spacer 20 as a first embodiment of the present invention. FIG. 2 is a view of the view shown in FIG. 1 as viewed from the upper side of the drawing. The vertebral body spacer 20 is an instrument (biological implant) that is placed between the adjacent first vertebral body 10A and the second vertebral body 10B and is implanted in the body. For example, the vertebral body spacer 20 is disposed between the first vertebral body 10A and the second vertebral body 10B instead of the damaged intervertebral disc. In the present embodiment, as shown in FIG. 2, two vertebral body spacers 20 are arranged side by side between the first vertebral body 10A and the second vertebral body 10B. When the first vertebral body 10A and the second vertebral body 10B are used without distinction, the vertebral body 10 is used.

  FIG. 3 is a first perspective view of the vertebral body spacer 20. FIG. 4 is a second perspective view of the vertebral body spacer 20. 1 and 2, the boundary between the first surface 21 and the first protrusion 30 and the boundary between the second surface 22 and the second protrusion 40 are indicated by broken lines for easy understanding. Yes.

  The vertebral body spacer 20 (FIG. 3) is a substantially rectangular parallelepiped member. The vertebral body spacer 20 has a length LS in the short direction SD, a length LL in the longitudinal direction LD, and a thickness direction (direction in which the two vertebral bodies 10A and 10B face each other) TL. The length is the length LT. The lengths LS, LL, and LT can be arbitrarily set according to the shape of the first vertebral body 10A and the second vertebral body 10B, the patient to be used, the surgical method, and the like. For example, the length LS can be set in the range of 5 to 12 mm, the length LL in the range of 18 to 26 mm, and the length LT in the range of 7 to 13 mm. The vertebral body spacer 20 includes a first surface 21, a second surface 22, first to fourth side surfaces 23, 24, 25, 26 as side surfaces, a first protrusion 30, a second protrusion 40, Have

  The first surface 21 is a plane that faces the first vertebral body 10A (FIG. 1). The second surface 22 is a flat surface facing the second vertebral body 10B (FIG. 1), and is located on the opposite side to the first surface 21. The direction in which the first surface 21 and the second surface 22 face each other is the thickness direction TL of the vertebral body spacer 20. The first to fourth side surfaces 23, 24, 25, and 26 are planes that connect the first surface 21 and the second surface 22, respectively. The first side surface 23 and the third side surface 25 are opposed to the longitudinal direction LD of the vertebral body spacer 20. The second side surface 24 and the fourth side surface 26 oppose each other in the short direction SD of the vertebral body spacer 20. The thickness direction TL, the longitudinal direction LD, and the lateral direction SD are orthogonal to each other.

  The vertebral body spacer 20 further includes a first protrusion 30, a second protrusion 40, a first through hole 27, and a second through hole 28.

  The first through hole 27 is a single hole that penetrates the vertebral body spacer 20 in the thickness direction TL, and penetrates the first surface 21 and the second surface 22. The second through hole 28 is a hole that allows the first through fourth side surfaces 23, 24, 25, 26 and the first through hole 27 to communicate with each other. Eight second through holes 28 are formed. Specifically, the vertebral body spacer 20 includes one second through hole 28 (FIG. 3) that connects the first side surface 23 and the first through hole 27, and the second side surface 24 and the first through hole 27. Three second through holes 28 (FIG. 3) to be communicated, one second through hole 28 (FIG. 4) to communicate the third side surface 25 and the first through hole 27, the fourth side surface 26 and the first through hole. There are three second through holes 28 (FIG. 4) that communicate with the holes 27. Note that the second through hole 28 may be used to connect an insertion jig used when the vertebral body spacer 20 is inserted between the vertebral bodies 10.

  The first protrusion 30 (FIG. 3) protrudes from the first surface 21. A plurality of first protrusions 30 are provided adjacent to the longitudinal direction LD. Each of the first protrusions 30 extends in one direction along the first surface 21. In the present embodiment, each of the first protrusions 30 extends in a direction parallel to the short direction SD. That is, an uneven structure is formed on the first surface 21 by the first protrusion 30. The 1st protrusion part 30 has the edge part side 1st protrusion part 32 and the center side 1st protrusion part 31 from which a structure differs. The end portion side first protrusion 32 continuously extends from the end portion on the second side surface 24 side of the first surface 21 to the end portion on the fourth side surface 26 side. The middle first protrusion 31 is divided by the first through hole 27 in the middle. One side of the center side first protrusion 31 extends from the end of the first surface 21 on the second side surface 24 side to a portion where the first through hole 27 is located. The other side of the center side first protrusion 31 extends from the end of the first surface 21 on the fourth side surface 26 side to a portion where the first through hole 27 is located. The detailed configuration of the first protrusion 30 will be described later.

  The second protrusion 40 (FIG. 4) protrudes from the second surface 22. A plurality of second protrusions 40 are provided adjacent to the longitudinal direction LD. Each of the second protrusions 40 extends in one direction along the second surface 22. In the present embodiment, each of the second protrusions 40 extends in a direction parallel to the short direction SD. That is, an uneven structure is formed on the first surface 21 by the second protrusion 40. The 2nd protrusion part 40 has the edge part side 2nd protrusion part 42 and the center side 2nd protrusion part 41 from which a structure differs. The end-side second protrusion 42 continuously extends from the end on the second side surface 24 side of the second surface 22 to the end on the fourth side surface 26 side. The middle second protrusion 41 is divided by the first through hole 27 in the middle. One side of the center-side second protrusion 41 extends from the end of the first surface 21 on the second side surface 24 side to a portion where the first through hole 27 is located. The other side of the center-side second protrusion 41 extends from the end of the first surface 21 on the fourth side surface 26 side to a portion where the first through hole 27 is located. The detailed configuration of the second protrusion 40 will be described later.

  The vertebral body spacer 20 is made of a material mainly composed of a polymer material (50% by mass or more). Here, when the vertebral body spacer 20 is formed of a material having a metal material as a main component, it has high strength, but may have a high elastic modulus and lack toughness, and a portion where a large load is continuously applied. If it is placed in the position, there is a problem that stress shielding occurs due to a difference in mechanical properties with surrounding bones, and there is a problem that it is not directly coupled to bones. In addition, when bioceramics such as hydroxyapatite are selected as the material for the artificial bone, the bioceramics usually have good biocompatibility, high bioactivity, and excellent bone binding properties, but external Since it is vulnerable to impact, there is a problem that it cannot be used for a part where a large load is applied instantaneously. By forming the vertebral body spacer 20 from a material mainly composed of a polymer material, the possibility of the above-described problems occurring can be reduced.

  In the present embodiment, the vertebral body spacer 20 has a dense spacer body made of a polymer material and a porous layer formed on the entire surface of the spacer body. As the polymer material, for example, polyether ether ketone (PEEK) can be used. The polymer material may be a resin containing carbon fiber. For example, the vertebral body spacer 20 may have a composition of 70 to 90% by mass of PEEK and 10 to 30% by mass of carbon fiber.

PEEK is biocompatible and has mechanical properties similar to bone. Therefore, when PEEK is adopted as a material for forming the vertebral body spacer 20, the connectivity with the vertebral body 10 can be improved. For example, when the vertebral body spacer 20 is disposed at a site where a large load is continuously applied for a long period of time, it is possible to suppress a decrease in bone density and a decrease in bone density that may occur due to stress shielding, that is, shielding of stress applied to the bone. . The porous layer has an opening on the surface and a hole communicating to the inner side. The porous layer is formed by performing various treatments to be described later on the base material that is the basis of the vertebral body spacer 20 formed by PEEK. The porous layer may have a bioactive substance on the inner wall surface or surface of the hole. Thereby, after the vertebral body spacer 20 is disposed between the first vertebral body 10A and the second vertebral body 10B, a chemical reaction between the bioactive substance and the bone tissue of the living body starts, and formation of new bone is started. Promptly. Therefore, the bone (vertebral body 10) and the vertebral body spacer 20 can be joined at an early stage. The bioactive substance is not particularly limited as long as it has high affinity with a living body and has a property of chemically reacting with bone tissue. For example, calcium phosphate-based material, bioglass, crystallized glass (also called glass ceramics) ), Calcium carbonate and the like. Examples of calcium phosphate materials include calcium hydrogen phosphate, calcium hydrogen phosphate hydrate, calcium dihydrogen phosphate, calcium dihydrogen phosphate hydrate, α-type tricalcium phosphate, β-type tricalcium phosphate, Examples thereof include dolomite, tetracalcium phosphate, octacalcium phosphate, hydroxyapatite, fluorapatite, carbonate apatite, and chlorapatite. Examples of the bioglass include SiO ₂ —CaO—Na ₂ O—P ₂ O ₅ glass, SiO ₂ —CaO—Na ₂ O—P ₂ O ₅ —K ₂ O—MgO glass, and SiO ₂ —. Examples include CaO—Al ₂ O ₃ —P ₂ O ₅ glass. Examples of the crystallized glass include SiO ₂ —CaO—MgO—P ₂ O ₅ glass (also referred to as apatite wollastonite crystallized glass), CaO—Al ₂ O ₃ —P ₂ O ₅ glass, and the like. Is mentioned. These calcium phosphate materials, bioglass, and crystallized glass are, for example, “Chemical Handbook Applied Chemistry 6th Edition” (The Chemical Society of Japan, published on January 30, 2003, Maruzen Co., Ltd.), “Development of Bioceramics” And Clinical "(edited by Hideki Aoki et al., Published on April 10, 1987, Quintessence Publishing Co., Ltd.).

  As the bioactive substance, a calcium phosphate-based material is particularly preferable in terms of excellent bioactivity. More preferably, hydroxyapatite is used. This is because hydroxyapatite is similar in composition, structure, and properties to actual bones, and thus has excellent stability in the body environment and does not exhibit remarkable solubility in the body.

  FIG. 5 is a perspective view showing a part of the vertebral body spacer 20 on the first surface 21 side. 6 is a cross-sectional view taken along line F5A-F5A in FIG. 7 is a cross-sectional view taken along line F5B-F5B in FIG. The detailed structure of the 1st protrusion part 30 is demonstrated using FIGS. 6 and 7, the single hatched portion indicates a dense spacer body 29A, and the cross-hatched portion indicates a porous layer 29B.

  The end-side first protrusion 32 (FIG. 5) of the first protrusion 30 has a triangular prism shape, and the two bottom surfaces face each other in the short direction SD. The end-side first protrusion 32 forms a first side surface 326 that forms one of the side surfaces of the triangular prism and extends from the first surface 21, and the other one of the side surfaces of the triangular prism forms the first surface 21. And a second forming side surface 327 extending. Further, the end-side first protrusion 32 has a first top 321 and a first recess 36.

  The first top portion 321 forms an angle (for example, an angle having an inner angle of 30 degrees to 60 degrees) by the first forming side surface 326 and the second forming side surface 327 intersecting each other. The first apex 321 is a portion that bites into the opposing first vertebral body 10A when the vertebral body spacer 20 is disposed between the first vertebral body 10A and the second vertebral body 10B. The first recess 36 is formed at a position different from the first top portion 321 in the lateral direction SD that is one direction along the first surface 21. The first recessed portion 36 is a portion that does not have the first top portion 321 in the end side first projecting portion 32. The first recess 36 has a first plane part 323 and a first sub-plane part 324 arranged at different height positions with respect to the first surface 21. The first plane portion 323 and the first sub-plane portion 324 are surfaces parallel to the first surface 21 and constitute the bottom surface of the first recess 36. The first plane portion 323 and the first sub-plane portion 324 are surfaces that connect the first formation side surface 326 and the second formation side surface 327. Moreover, the 1st plane part 323 and the 1st subplane part 324 (FIG. 7) are the both ends connected to the 1st surface 21 among the edge part side 1st protrusion parts 32 in the cross section orthogonal to the transversal direction SD. It is a plane parallel to an imaginary line (the first surface 21 in the present embodiment) connecting 32E1 and 32E2. Note that the imaginary line and the first surface 21 do not have to coincide with each other, and the first surface 21 may be a curved surface. The first plane portion 323 and the first sub-plane portion 324 are not limited to surfaces parallel to the first surface 21, and may be surfaces extending in a direction along the first surface 21. The “direction along the first surface 21” includes not only a direction parallel to the first surface 21 but also a direction inclined at an angle of 10 degrees or less with respect to the first surface 21.

  It is preferable that the first flat surface portion 323 and the first sub flat surface portion 324 face each other (facing) with a slight gap from the first vertebral body 10A in the initial stage of the arrangement state. Thereby, the growth of the bone tissue in the initial stage of the arrangement state can be accepted by this gap. The first sub-plane portion 324 is located closer to the first surface 21 than the first top portion 321. The first plane portion 323 is located closer to the first surface 21 than the first top portion 321 and the first sub-plane portion 324. The first flat surface portion 323 forms the bottom surface located closest to the first surface 21 among the bottom surfaces of the first recesses 36.

  The center-side first protrusion 31 (FIG. 5) of the first protrusion 30 is different from the end-side first protrusion 32 in that the portion that becomes the first flat portion 323 is hollow by the first through hole 27. Different. The center side first protrusion 31 has a triangular prism shape, and two bottom surfaces face each other in the short direction SD. The center side first projecting portion 31 forms one of the side surfaces of the triangular prism and extends from the first surface 21, and the other one of the side surfaces of the triangular prism extends from the first surface 21. A second forming side surface 317. The center-side first protrusion 31 includes a first top 311 and a first recess 35.

  The first top portion 311 has the same configuration as the first top portion 321. For example, the first apex 311 forms a corner by the intersection of the first forming side 326 and the second forming side 327, and bites into the first vertebral body 10A facing each other in the arrangement state. The first recess 35 is formed at a position different from the first apex 311 in the short direction SD that is one direction along the first surface 21. The first recess 35 is a portion that does not have the first top portion 311 in the central first protrusion 31. The first concave portion 35 has a first flat surface portion 313 that is located closer to the first surface 21 than the first top portion 311. The first plane portion 313 is a surface corresponding to the first sub plane portion 324 of the end side first protrusion 32. The first plane part 313 constitutes the bottom surface of the first recess 35.

  The protrusion height of the first protrusion 30 (FIG. 7) is the height H1, and the width in the cross section orthogonal to the short direction SD is the width W1. The height H1 and the width W1 can be arbitrarily set according to the shape of the first vertebral body 10A and the second vertebral body 10B. For example, the height H1 can be set to a range of 0.6 to 1.4 mm, and the width W1 can be set to a range of 1.5 to 2.5 mm. In addition, each of the first plane portion 323, the first sub-plane portion 324, and the first plane portion 313 draws a perpendicular from the thickness direction TL (from the first top portions 321 and 311 to the first surface 21 forming the virtual line. In the direction), the first top portions 321 and 311 are preferably arranged at a distance of 5% to 50% of the height H1 of the first top portions 321 and 311. For example, each of the first plane portion 323, the first sub-plane portion 324, and the first plane portion 313 is preferably disposed at a position separated from the corresponding first top portions 321 and 311 by a range of 50 to 500 μm. . By arranging the first plane portion 323, the first sub-plane portion 324, and the first plane portion 313 in this range, the following effects can be obtained. That is, when the first apex 321 and 311 receive a load (for example, 5000 N) from the first vertebral body 10A in the arrangement state, the first protrusion 30 (the first apex 321 and 311 is applied to the first vertebral body 10A). ) Or the first protrusion 30 (the first apex 321, 311) is crushed by the first vertebral body 10 </ b> A. For example, about 8 to 10% of the height H1 by the vertebral body 10 is reduced when the first projecting portion 30 is crushed or bites into the first vertebral body 10A, so that the height H1 is reduced in the arrangement state. To do. Therefore, by designing the first protrusion 30 in consideration of the decrease in the height H1, the space between the first vertebral body 10A and the first plane portion 323, the first sub plane portion 324, and the first plane portion 313 is determined. In addition, it is possible to satisfactorily form a predetermined interval (for example, about 30 μm) about the size of a cell contributing to bone formation.

  FIG. 8 is a perspective view showing a part of the vertebral body spacer 20 on the second surface 22 side. The detailed structure of the 2nd protrusion part 40 is demonstrated using FIG. The second protrusion 40 is different from the first protrusion 30 only in that the formed surface is the second surface 22 instead of the first surface 21. The 2nd protrusion part 40 has the edge part side 2nd protrusion part 42 and the center side 2nd protrusion part 41 from which a structure differs.

  The end-side second protrusion 42 has the same configuration as the end-side first protrusion 32, and includes a first forming side 426, a second forming side 427, first and second forming side surfaces 426, 427, and the like. And a second top part 421 that forms a corner, and a second concave part 46 that is formed at a position different from the second top part 421 in the lateral direction SD (one direction along the second surface 22). The second recess 46 has the same configuration as the first recess 36, and has a second plane part 423 and a second sub plane part 424 that are arranged at different height positions with the second surface 22 as a reference. The second plane part 423 has the same configuration as the first plane part 323, and the second sub plane part 424 has the same configuration as the first sub plane part 324. The second plane portion 423 and the second sub-plane portion 424 are located closer to the second surface 22 than the second top portion 421. The second plane part 423 and the second sub plane part 424 are surfaces parallel to the second surface 22. The second plane portion 423 and the second sub-plane portion 424 are not limited to surfaces parallel to the second surface 22, and may be surfaces extending in a direction along the second surface 22. The “direction along the second surface 22” includes not only a direction parallel to the second surface 22 but also a direction inclined at an angle of 10 degrees or less with respect to the second surface 22.

  The center-side second projecting portion 41 has the same configuration as the center-side first projecting portion 31, and the first forming side surface 416, the second forming side surface 417, and the first and second forming side surfaces 416, 417 intersect. Thus, the second top portion 411 that forms a corner and the second concave portion 45 formed at a position different from the second top portion 411 in the short-side direction SD are included. The second recess 45 has the same configuration as that of the first recess 35 and has a second flat surface portion 413 that is located on the second surface 22 side with respect to the second top portion 411.

  FIG. 9 is a process flow showing the manufacturing process of the vertebral body spacer 20. First, a base material from which the vertebral body spacer 20 is based is prepared (step S10). Specifically, the base material is produced by cutting a plastic material (for example, PEEK) so as to have the shape of the vertebral body spacer 20. This base material has the external shape shown in FIG. 3 and FIG. In addition, it may replace with cutting and may produce a base material by injection molding using a metal mold | die.

  Next, many micropores are formed on the substrate surface (step S20). A well-known method can be employ | adopted as a method of forming a micropore on the base-material surface. For example, a method in which a plastic substrate is immersed in a corrosive solution such as concentrated sulfuric acid, concentrated nitric acid, or chromic acid for a predetermined time, and then the substrate is immersed in a cleaning solution that does not elute the plastic, such as pure water. Can be mentioned. When, for example, polyether ether ketone (PEEK) is used as the plastic, micropores can be formed by immersing PEEK in concentrated sulfuric acid for a predetermined time and then immersing it in pure water. A large number of microporous layers formed on the surface of the base material become the porous layer 29B.

  Next, a foaming agent holding base material is produced in which the foaming agent is held on the surface of the base material having a large number of micropores (step S30). The foaming agent may be any substance that can form a desired porous structure on the surface of a plastic substrate, and as such a foaming agent, an inorganic foaming agent such as carbonate or aluminum powder, Examples thereof include organic foaming agents such as azo compounds and isocyanate compounds. The foaming agent is preferably a substance that does not adversely affect the living body, and as such a foaming agent, carbonates are preferable, and examples thereof include sodium hydrogen carbonate, sodium carbonate, and potassium carbonate.

  Next, a foaming base material is produced from the foaming agent holding base material (step S40). Specifically, the foaming agent holding substrate is immersed for a predetermined time in a foaming solution that swells the plastic and foams the foaming agent, so that the swelling of the plastic and the foaming of the foaming agent proceed simultaneously. Thereafter, the foamed substrate is produced by immersing it in a coagulation solution that coagulates the swollen plastic. Examples of the foaming solution include acidic solutions such as concentrated sulfuric acid, hydrochloric acid, and nitric acid. When the material for forming the foaming agent holding substrate is PEEK and the foaming agent is carbonate, the sulfuric acid is preferably concentrated sulfuric acid having a concentration of 90% or more as the foaming solution. Examples of the coagulation solution, that is, a solution from which the plastic does not elute, include aqueous solutions such as water, acetone, and ethanol. When the material for forming the foamed substrate is PEEK, in addition to the above, there are aqueous solutions of inorganic acids such as sulfuric acid, nitric acid, phosphoric acid, hydrochloric acid and the like, water-soluble organic solvents having a concentration of less than 90%. Examples of the water-soluble organic solvent include N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, ethylene glycol, diethylene glycol, trietylene glycol, propylene glycol, diester. Alcohols such as propylene glycol, glycerol ethanol, propanol, butanol, pentanol, hexanol and the like and their aqueous solutions, polyethylene glycol, polypropylene glycol, polyvinyl pyrrolidone, etc. Mention may be made of molecules or their aqueous solutions and mixtures thereof.

  Next, hydroxyapatite particles are immobilized on the surface of the foamed substrate (step S50). Thereby, the hydroxyapatite particles are immobilized on the inner wall surface and the surface of the porous layer 29B. As the immobilization method, for example, the following method can be used. First, a dispersion solution in which hydroxyapatite particles are dispersed in an ethanol solution is prepared. Next, the foamed base material is immersed in the dispersion solution, and ultrasonic waves are applied to the dispersion solution in the immersed state. Thereby, the hydroxyapatite particles adhere uniformly to the surface of the foamed substrate. Next, the foamed substrate is taken out of the dispersion solution and dried under predetermined conditions (for example, at a temperature of about 230 ° C. for 20 minutes) to immobilize the hydroxyapatite particles. The vertebral body spacer 20 is produced by performing Step S10 to Step S50.

  According to the first embodiment, as shown in FIGS. 5 and 8, the first protrusion 30 has the first flat surfaces 323 and 313, and the second protrusion 40 has the second flat portions 423 and 413. Have. Moreover, the 1st protrusion part 30 containing the 1st plane parts 323 and 313 and the 2nd protrusion part 40 containing the 2nd plane parts 423 and 413 have the porous layer 29B on the surface, respectively. Thereby, compared with the case where the 1st protrusion part 30 and the 2nd protrusion part 40 do not have a plane part, it is a predetermined space | interval (for example, the space | interval of the magnitude | size of the cell which contributes to bone formation) with respect to the opposite vertebral body 10. More porous layers 29B can be arranged at positions where the Thereby, when the vertebral body spacer 20 is disposed between the two vertebral bodies 10, more of the bone tissue of the vertebral body 10 can be received in the porous layer 29B earlier after the placement. Therefore, the connectivity between the vertebral body 10 and the vertebral body spacer 20 can be improved. In addition, since the connectivity between the vertebral body 10 and the vertebral body spacer 20 can be improved earlier, the possibility that the vertebral body spacer 20 is displaced from the original arrangement position can be reduced. That is, the stability of the long-term position of the vertebral body spacer 20 can be improved. Moreover, according to the said embodiment, the 1st plane part 323,313 and the 2nd plane part 423,413 can be easily formed with the bottom face of the 1st recessed parts 36 and 35 and the 2nd recessed parts 46 and 45. FIG.

  Here, the vertebral body spacer 20 receives a load from the vertebral body 10 when it is disposed between the vertebral bodies 10. This load takes various values for each patient using the vertebral body spacer 20. Due to this load, the first protrusion 30 (first apex 321, 311) and the second protrusion 40 (second apex 421, 411) of the vertebral body spacer 20 are partially crushed or partially vertebral body 10. Or buried inside. As a result, the distance (gap distance) between the first surface 21 and the second surface 22 and the vertebral body 10 facing the first surface 21 and the second surface 22 changes. According to the above embodiment, as shown in FIG. 5, the first recess 36 has the first sub-plane portion 324 arranged at a height position different from the first plane portion 323 in addition to the first plane portion 323. . Further, according to the embodiment, as shown in FIG. 8, the second recess 46 has the second sub-plane portion 424 in addition to the second plane portion 423. Thereby, the plane part (the first plane part 323, the second plane part 423, or the plane part having a predetermined interval with respect to the vertebral body 10 corresponding to the gap distance that changes for each patient using the vertebral body spacer 20 A first sub-plane portion 324 and a second sub-plane portion 424) can be provided.

  Further, according to the first embodiment, the vertebral body spacer 20 has the first through hole 27 (FIG. 3). Thereby, when the bone tissue of the vertebral body 10 facing the first surface 21 or the second surface 22 grows, the grown bone tissue can be received by the first through-hole 27, so that the vertebral body 10 and the vertebral body spacer The bondability with 20 can be further improved. Furthermore, according to the above embodiment, the vertebral body spacer 20 has the second through hole 28 (FIGS. 3 and 4). Thereby, when the bone tissue of the vertebral body 10 grows to a position facing the first to fourth side surfaces 23, 24, 25, 26, the bone tissue grown by the second through hole 28 can be received. Therefore, the connectivity between the vertebral body 10 and the vertebral body spacer 20 can be further improved.

B. Second embodiment:
FIG. 10 is a view of a vertebral body spacer 20a as a second embodiment of the present invention viewed from the first surface 21 side. 11 is a cross-sectional view taken along line F10-F10 in FIG. In FIG. 11, a broken line is attached to the boundary between the first surface 21 and the first protrusion 30a and the boundary between the second surface 22 and the second protrusion 40a for easy understanding.

  The vertebral body spacer 20 (FIG. 3) and the vertebral body spacer 20 a of the first embodiment are different from each other in the configuration of the first protrusion 30 a and the second protrusion 40 a, and the vertebral body spacer 20 a is the first through hole 27. In addition, the second through hole 28 is not provided. Since other configurations are the same in the vertebral body spacer 20 and the vertebral body spacer 20a, the same components are denoted by the same reference numerals and description thereof is omitted. Like the vertebral body spacer 20 (FIG. 6), the vertebral body spacer 20a (FIG. 11) has a spacer body 29A and a porous layer 29B formed on the surface of the spacer body 29A. The vertebral body spacer 20a is manufactured by the same manufacturing process (steps S10 to S50 in FIG. 9) as the vertebral body spacer 20 of the first embodiment.

  The vertebral body spacer 20a is a substantially rectangular parallelepiped member. The vertebral body spacer 20 a has a first protrusion 30 a that protrudes from the first surface 21. In addition, the vertebral body spacer 20 a includes a second projecting portion 40 a that projects from the second surface 22. Since the structure of the 1st protrusion part 30a and the 2nd protrusion part 40a is the same, description of the 2nd protrusion part 40a is abbreviate | omitted suitably.

  A plurality of first protrusions 30 a are provided on the first surface 21. In the present embodiment, four first protrusions 30a are provided along the longitudinal direction LD and two along the short direction SD. Adjacent first protrusions 30a are arranged adjacent to each other. The first protrusion 30 a is connected to the first surface 21, and includes a base portion 391 protruding from the first surface 21 and a corner forming portion 392 protruding from the upper surface of the base portion 391.

  The base portion 391 has a frustum shape. In the present embodiment, the base portion 391 has a quadrangular pyramid shape. The base portion 391 has a first flat surface portion 383 that forms the upper base, and four side surface portions 396a, 396b, 396c, and 396d that connect the first flat surface portion 383 and the first surface 21 that forms the lower base. The 1st plane part 383 is located in the 1st surface 21 side rather than the 1st top part 399 of the angle | corner formation part 392 mentioned later. The first plane portion 383 is a surface parallel to the first surface 21. The first plane portion 383 is slightly spaced from the first vertebral body 10A (FIG. 1) at the initial stage of the arrangement state, like the first plane portions 323 and 313 and the first sub-plane portion 324 of the first embodiment. It is preferable to open and face each other. Thereby, the growth of the bone tissue in the initial stage of the arrangement state can be accepted by this gap. The first flat surface portion 383 is not limited to a surface parallel to the first surface 21, and may be a surface extending in a direction along the first surface 21. The “direction along the first surface 21” includes a direction inclined at an angle of 10 degrees or less with respect to the first surface 21 in addition to a direction parallel to the first surface 21 as in the first embodiment.

  The corner forming portion 392 is disposed at the center of the first plane portion 383. The corner forming portion 392 has a cone shape. In the present embodiment, the corner forming part 392 has a quadrangular pyramid shape. The angle forming portion 392 includes a first apex portion 399 that constitutes the apex of the quadrangular pyramid shape, and four side surface portions 398a, 398b, 398c, and 398d having the quadrangular pyramid shape. The first top portion 399 forms a corner by the intersection of the four side surface portions 398a, 398b, 398c, and 398d. The first apex 399 is a portion that bites into the opposing first vertebral body 10A when the vertebral body spacer 20 is disposed between the first vertebral body 10A and the second vertebral body 10B.

  The second protrusion 40 a (FIG. 11) is connected to the second surface 22, and includes a base portion 491 protruding from the second surface 21 and a corner forming portion 492 protruding from the upper surface of the base portion 491. The base portion 491 has the same configuration as the first projecting portion 30a, and four side surface portions that connect the second plane portion 483 that forms the upper base and the second plane 22 that forms the second plane portion 483 and the lower base. 496a and 496c (only two side portions are shown in the figure). The second flat surface portion 483 is a surface parallel to the second surface 22. The second flat surface portion 483 is not limited to a surface parallel to the second surface 22, and may be a surface extending in a direction along the second surface 22. The “direction along the second surface 22” includes not only a direction parallel to the second surface 22 but also a direction inclined at an angle of 10 degrees or less with respect to the second surface 22 as in the first embodiment. The angle forming portion 492 has the same configuration as that of the first embodiment, and includes a second apex portion 499 constituting the apex of the quadrangular pyramid shape, and four side surface portions 498a and 498c having the quadrangular pyramid shape (only two side surface portions in the drawing). As shown). The second top portion 499 forms a corner by intersecting the four side surface portions 498a and 498c. The second apex 499 is a portion that bites into the second vertebral body 10B facing each other when the vertebral body spacer 20 is disposed between the first vertebral body 10A and the second vertebral body 10B.

  According to the said 2nd Embodiment, there exists the same effect in the point which has the structure similar to 1st Embodiment. For example, the first protrusion 30 a has a first plane part 383, and the second protrusion 40 a has a second plane part 483. The first protrusion 30a including the first plane part 383 and the second protrusion 40a including the second plane part 483 each have a porous layer 29B on the surface. Thereby, compared with the case where the 1st protrusion part 30a and the 2nd protrusion part 40a do not have a plane part, it is a predetermined space | interval (for example, the space | interval of the magnitude | size of the cell which contributes to bone formation) with respect to the opposite vertebral body 10. More porous layers 29B can be arranged at positions where the Thereby, when the vertebral body spacer 20a is arranged between the two vertebral bodies 10, more of the bone tissue of the vertebral body 10 can be received in the porous layer 29B earlier after the arrangement. Therefore, the connectivity between the vertebral body 10 and the vertebral body spacer 20a can be improved. In addition, since the connectivity between the vertebral body 10 and the vertebral body spacer 20a can be improved earlier, the possibility that the vertebral body spacer 20a is displaced from the original arrangement position can be reduced. That is, the stability of the long-term position of the vertebral body spacer 20a can be improved.

  In the second embodiment, the vertebral body spacer 20 a may have the first through hole 27 and the second through hole 28, similarly to the vertebral body spacer 20. In addition, the vertebral body spacer 20 a may have a first sub-plane portion or a second sub-plane portion, similarly to the vertebral body spacer 20. The first sub-plane portion is formed at a height position different from that of the first plane portion 383 with respect to the first surface 21 and on the first surface 21 side with respect to the first top portion 399. The second sub-plane portion is formed at a height position different from that of the second plane portion 483 with respect to the second surface 22 and closer to the second surface 22 than the second top portion 499. The vertebral body spacer 20a may have a plurality of first sub-plane portions and a plurality of second sub-plane portions arranged at different height positions.

C. Variations:
In addition, this invention is not restricted to said embodiment, In the range which does not deviate from the summary, it can implement in a various aspect.

C-1. First modification:
In the above embodiment, the vertebral body spacers 20 and 20a are substantially rectangular parallelepiped members, and the surfaces 21, 22, 23, 24, 25, and 26 are flat surfaces. The shape is not limited to the above, and any shape that can be arranged between the vertebral bodies 10 is acceptable. A modification of the shape of the vertebral body spacer will be described below. FIG. 12 is a view for explaining a vertebral body spacer 20b of the first modification. The difference between the vertebral body spacer 20b and the vertebral body spacer 20 of the first embodiment is that the first surface 21b and the second surface 22b are curved surfaces. The 1st surface 21b and the 2nd surface 22b are circular arc shape in the side view seen from the transversal direction SD. The first plane portion 323 and the first sub-plane portion 324 are planes parallel to a virtual line VP connecting both end portions 32E1 and 32E2 in the cross section orthogonal to the short direction SD, as in the first embodiment. Similarly, for the second plane portion 423 and the second sub-plane portion 424, a plane parallel to an imaginary line connecting both ends connected to the second surface 22 of the end-side second protruding portion 42 formed with itself. It is.

C-2. Second modification:
In the first embodiment, the vertebral body spacer 20 has the first and second sub-plane portions 324 and 424 (FIGS. 5 and 8), but may not be provided. A plurality of first and second sub-plane portions 324 and 424 may be provided at different height positions from the first and second plane portions 323 and 423. The plurality of first and second sub-plane portions 324 and 424 are disposed at different height positions with respect to the first surface 21 and the second surface 22, respectively.

C-3. Third modification:
In the said 1st Embodiment, although the 1st protrusion part 30 and the 2nd protrusion part 40 were triangular prism shape, if the 1st top part 321,311 and the 2nd top part 421,411 are formed, the 1st protrusion part The shape of 30 and the 2nd protrusion part 40 is not limited to this. For example, the cross-sectional shape orthogonal to the direction in which it extends (the short direction SD) may be a polygon such as a pentagon, or a combination of a curve and a straight line. Similarly, in the second embodiment, if the first flat portion 383, the first top portion 399, the second flat portion 483, and the second top portion 499 are provided, the first protruding portion 30a and the second protruding portion 40a. The shape is not limited to the second embodiment. For example, the first projecting portion 30a includes a columnar base portion 391 that forms the first flat surface portion 383 on the upper surface, and a corner forming portion 392 that has a sharp upper portion that protrudes from the first flat surface portion 383 of the base portion 391. It may be. The bottom of the corner forming part 392 has a smaller area than the first flat part 383. The same applies to the configuration of the second protrusion 40a. Specifically, for example, the base portion 391 of the first projecting portion 30a and the base portion 491 of the second projecting portion 40a may have a truncated cone shape, and the corner forming portions 392 and 492 may have a conical shape. Good.

C-4. Fourth modification:
In the first and second embodiments, the porous layer 29B is formed on the entire surface of the vertebral body spacer 20, but is formed on at least the surfaces of the first protrusions 30 and 30a and the second protrusions 40 and 40a. Just do it.

C-5. Fifth modification:
In the first embodiment, the first through hole 27 is a single hole and the second through hole 28 is eight holes. However, the number of the first through hole 27 and the second through hole 28 is not limited to these. It is not limited. For example, a plurality of (for example, two) first through holes 27 may be formed. In addition, the second through hole 28 may be formed in plural (for example, six) other than eight, or only one may be formed.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Vertebral body 10A ... 1st vertebral body 10B ... 2nd vertebral body 20, 20a, 20b ... Vertebral body spacer 21,21a ... 1st surface 22, 22a ... 2nd surface 23 ... 1st side surface 24 ... 2nd side surface 25 ... 3rd side surface 26 ... 4th side surface 27 ... 1st through-hole 28 ... 2nd through-hole 29A ... Spacer main body 29B ... Porous layer 30, 30a ... 1st protrusion part 31 ... Center side 1st protrusion part 32 ... End part side 1st protrusion part 35, 36 ... 1st recessed part 40, 40a ... 2nd protrusion part 41 ... 2nd protrusion part 42 in the center side 2nd protrusion part 45, 46 ... 2nd recessed part 311 ... 1st top part 313 ... 1st plane part 316 ... 1st formation side surface 317 ... 2nd formation side surface 32E1 ... End part 321 ... 1st top part 323 ... 1st plane part 324 ... 1st subplane part 326 ... 1st formation side surface 327 ... 2nd formation side surface 383: First plane portion 391: Base portion 392 ... Corner forming portion 396a, 396b, 396c, 396d ... side surface portion 398a, 398b, 398c, 398d ... side surface portion 399 ... first top portion 411 ... second top portion 413 ... second flat surface portion 416 ... first forming side surface 417 ... second forming side surface 421 ... Second top portion 423 ... second plane portion 424 ... second sub-plane portion 426 ... first formation side surface 427 ... second formation side surface 483 ... second plane portion 491 ... base portion 492 ... corner formation portions 496a, 496c ... side portion 498a , 498c ... side face part 499 ... second top part LD ... longitudinal direction SD ... short direction TL ... thickness direction VP ... virtual line W1 ... width

Claims (12)

A vertebral body spacer having a first surface and a second surface located on the opposite side of the first surface, the vertebral body spacer being disposed between adjacent vertebral bodies,
A first protrusion protruding from the first surface;
A second projecting portion projecting from the second surface,
The first projecting portion includes a first top portion that forms a corner, and a first flat portion that is located on the first surface side of the first top portion and extends in a direction along the first surface. ,
The second projecting portion includes a second top portion that forms a corner, and a second flat portion that is positioned on the second surface side of the second top portion and extends in a direction along the second surface. ,
Each of the first protrusion and the second protrusion has a porous layer on the surface thereof, and the vertebral body spacer is characterized in that The vertebral body spacer according to claim 1,
The first protrusion extends in one direction along the first surface,
The second protrusion extends in one direction along the second surface,
The first protrusion further includes a first recess formed at a position different from the first top in one direction along the first surface,
The second protrusion further includes a second recess formed at a position different from the second top in one direction along the second surface,
The first plane portion is formed by a bottom surface of the first recess,
The vertebral body spacer, wherein the second flat portion is formed by a bottom surface of the second recess. The vertebral body spacer according to claim 1 or 2, further comprising:
A vertebral body spacer having a first through hole penetrating over the first surface and the second surface. The vertebral body spacer according to claim 3, further comprising:
A side surface connecting the first surface and the second surface;
A vertebral body spacer comprising: a second through hole that communicates the side surface with the first through hole. The vertebral body spacer according to any one of claims 1 to 4,
The first protrusion further includes
A first sub-plane portion formed at a height position different from the first plane portion with respect to the first surface and at a position closer to the first surface than the first top portion; A vertebral body spacer having a first sub-plane portion extending in a direction along one surface. The vertebral body spacer according to claim 5,
The second protrusion further includes
A second sub-plane portion formed at a height position different from the second plane portion with respect to the second surface and at a position closer to the second surface than the second top portion, A vertebral body spacer having a second sub-plane portion extending in a direction along two surfaces. The vertebral body spacer according to any one of claims 1 to 6,
The vertebral body spacer is made of a material mainly composed of a polymer material. The vertebral body spacer according to claim 7,
The vertebral body spacer is characterized in that the polymer material is a material selected from the group consisting of polyetheretherketone and a resin containing carbon fiber and polyetheretherketone. The vertebral body spacer according to any one of claims 1 to 8,
The vertebral body spacer is characterized in that the porous layer is formed on the entire surface of the vertebral body spacer. The vertebral body spacer according to any one of claims 1 to 9,
The vertebral body spacer, wherein the porous layer has a bioactive substance. The vertebral body spacer according to claim 10,
The vertebral body spacer, wherein the bioactive substance is calcium phosphate. The vertebral body spacer according to claim 11,
The vertebral body spacer, wherein the calcium phosphate is hydroxyapatite.

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