Spinal implant and method of manufacturing a spinal implant

Abstract

A spinal implant has a base and a coating disposed on the base and including a calcium phosphate material and an antibacterial agent, the surface of the base having a first region in which the coating is disposed and a second region in which the coating is exposed.

Description

Technical Field

[0001] This invention relates to a spinal implant that is inserted between adjacent vertebrae to repair the intervertebral disc. Background Technology

[0002] Previously, there was a known spinal implant for repairing intervertebral discs removed during surgery to improve degenerative or diseased conditions such as hernias. For example, Patent Document 1 describes a vertebral implant having grooves and ridges on the upper and lower surfaces of the main body.

[0003] Furthermore, Patent Document 2 describes a coating used in medical implants, which contains a bone-binding agent in a portion and an antibacterial metal agent containing silver. Patent Documents 3 and 4 describe biological implants having a coating formed of a calcium phosphate-based material.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 2003-526458

[0007] Patent Document 2: Japanese Patent Publication No. 2011-512959

[0008] Patent Document 3: Japanese Patent Application Publication No. 2008-73098

[0009] Patent Document 4: International Publication No. 2013 / 114947 Summary of the Invention

[0010] A spinal implant according to one aspect of the present invention comprises: a substrate; and a membrane disposed on the substrate and comprising a calcium phosphate-based material and an antibacterial agent, wherein the surface of the substrate has a first region on which the membrane is disposed and a second region exposed from the membrane.

[0011] One aspect of the present invention provides a spinal implant comprising: a substrate; and a covering disposed on the substrate and comprising a calcium phosphate-based material and an antibacterial agent, the covering having a first region and a sixth region having a thickness smaller than the first region.

[0012] One aspect of the present invention provides a method for manufacturing a spinal implant, comprising a coating forming step of locally forming a coating comprising a calcium phosphate-based material and an antibacterial agent on a substrate.

[0013] A method for manufacturing a spinal implant according to one aspect of the present invention includes: a step of preparing a substrate; and a step of forming a coating on the substrate, the coating comprising a calcium phosphate-based material and an antibacterial agent, and having a first region and a sixth region with a thickness smaller than the first region. Attached Figure Description

[0014] Figure 1 This is a diagram illustrating an example of how a spinal implant according to an embodiment of the present invention is used.

[0015] Figure 2 This is a 3D diagram of a spinal implant.

[0016] Figure 3 This is a top view of a spinal implant.

[0017] Figure 4 This is a side view of a spinal implant.

[0018] Figure 5 This demonstrates the use of implants in the spine. Figure 4 A diagram of the cut surface when the line AA is cut off.

[0019] Figure 6 This is a three-dimensional diagram of a retention device for spinal implants.

[0020] Figure 7 This diagram shows the state after the spinal implant is connected to the retainer. Detailed Implementation

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0022] Previously, there was no specific mention of reducing the amount of antimicrobial metal in the coating of spinal implants inserted into the body. However, when applying coatings containing antimicrobial metal to spinal implants inserted into the body, it is sometimes desirable to reduce the amount of antimicrobial metal on various surfaces.

[0023] Therefore, in one aspect of the present invention, the amount of antibacterial metal agent can be reduced in a spinal implant having a coating with an antibacterial metal agent. Specific details are described below.

[0024] [Implementation Method 1]

[0025] The following describes in detail one embodiment of the present invention. The spinal implant of this embodiment is inserted between adjacent vertebrae to replace or repair an intervertebral disc, and is used to replace, correct, or repair the height of the spinal structure. It should be noted that the spinal implant inserted between adjacent vertebrae is also referred to, for example, as an intervertebral spacer, intervertebral segment, or intervertebral cage.

[0026] [How to use]

[0027] First, refer to Figure 1 Instructions on how to use spinal implant 1. Figure 1This diagram illustrates an example of how the spinal implant 1 is used. For ease of explanation, the direction indicated by the forward arrow will be referred to as the anterior or frontal side. The direction indicated by the backward arrow will be referred to as the posterior or rearward side. The direction indicated by the upward arrow will be referred to as the upper or upper side. The direction indicated by the downward arrow will be referred to as the lower or lower side. The direction indicated by the right arrow will be referred to as the right side. The direction indicated by the left arrow will be referred to as the left side. Figure 1 The front side of the body is the abdominal side. Figure 1 The back side of the spine is the side of the human body.

[0028] The spinal implant 1 of this embodiment is used in PLIF (Posterior Lumbar Interbody Fusion), one of the interbody fixation techniques used in surgeries such as those for disc herniation. In this PLIF, after decompression by removing bone that is compressing the nerve, the spinous process and facet joint are removed or partially removed, and the intervertebral disc and cartilaginous endplate are removed. Then, the spinal implant 1 is inserted between adjacent vertebrae 50 to repair the portion of the removed intervertebral disc.

[0029] Spinal implant 1 in a retainer 100 having a rod-shaped portion (see reference) Figure 6 While maintaining this position, insert it from the back, that is, along the spine in the front-to-back direction of the body, into the intervertebral space. Typically, as... Figure 1 As shown, two spinal implants 1 are inserted between two adjacent vertebrae 50 in a left-right arrangement. Then, a metal rod (not shown) is erected and fixed to each vertebra 50 across the two vertebrae 50 to which the spinal implants 1 are inserted, thereby fixing the two vertebrae 50 to each other.

[0030] It should be noted that the spinal implant 1 in this embodiment is not limited to PLIF, and can also be used in other surgical procedures, such as TLIF (Transforaminal Lumbar Interbody Fusion). In this case, the spinal implant 1 is inserted from either side in the left-right direction between the vertebrae.

[0031] [Structure of spinal implant 1]

[0032] Next, refer to Figures 2-5 The structure of spinal implant 1 is described. Figures 2-5 This is a diagram showing the structure of the spinal implant 1. Figure 2 This is a 3D view of spinal implant 1. Figure 3 This is a top view of spinal implant 1. Figure 4 This is a side view of spinal implant 1. Figure 5 It is shown in Figure 4 The diagram shows the cut surface when cut at line AA.

[0033] like Figure 2 As shown, the spinal implant 1 of this embodiment is formed from a generally cuboid-shaped base 2 extending in the front-back direction, and includes a front surface 3, a rear surface 4, a right side surface 5, a left side surface 6, an upper surface 8, and a lower surface 9. Furthermore, a cavity 7, which is elliptical in shape when viewed from the upper surface 8 and the lower surface 9, is provided from the upper surface 8 to the lower surface 9, and one or more holes 5a and 6a are provided on the right side surface 5 and the left side surface 6. The multiple holes 5a and 6a are circular in shape when viewed from the right side surface 5 and the left side surface 6.

[0034] It should be noted that the spinal implant 1 is not limited to a roughly rectangular shape; for example, it can also be roughly cubic. Furthermore, the shape of the cavity 7 when viewed from the upper surface 8 and lower surface 9 is not limited to an ellipse; for example, it can also be a circle or a quadrilateral. Additionally, the shape of the plurality of holes 5a and 6a observed from the right side 5 and left side 6 is not limited to a circle; for example, it can also be a quadrilateral.

[0035] Furthermore, the area of ​​the opening surface (elliptical) of the cavity 7 is larger than the area of ​​the opening surface (approximately circular) of the side holes 5a and 6a. The cavity 7 can also be provided on the rear surface 4 of the base 2. That is, the distance from the cavity 7 to the front surface 3 can also be smaller than the distance from the cavity 7 to the rear surface 4.

[0036] Alternatively, the side holes 5a and 6a can also be located on the rear surface 4 of the base 2. That is, the distance from the side holes 5a and 6a to the front surface 3 can be smaller than the distance from the side holes 5a and 6a to the rear surface 4. Furthermore, the side holes 5a and 6a extend into the cavity 7, and the area of ​​the opening on the right side surface 5 or the left side surface 6 is larger than the area of ​​the opening on the inner surface of the cavity 7. Additionally, the side holes 5a and 6a can also be conical.

[0037] Furthermore, a screw hole 4a (thread not shown) and a recess 4b are provided on the rear surface 4. The recess 4b is configured to form a groove (notch) from the rear surface 4 to the right side surface 5 or the left side surface 6 near the center in the vertical direction of the rear surface 4.

[0038] In this specification, for example, the vertical direction of the spinal implant 1 is defined as the first direction, the cavity 7 can be referred to as the first through part through which the base 2 passes in the first direction, and the spinal implant 1 can have the first through part through which the base 2 passes in the first direction.

[0039] Furthermore, if the left-right direction of the spinal implant 1 is defined as the second direction, the holes 5a and 6a through which the base 2 passes in the left-right direction can be referred to as second through portions through which the base 2 passes in the second direction intersecting the first direction. Moreover, the spinal implant 1 may have a second through portion through which the base 2 passes in the second direction intersecting the first direction.

[0040] In this embodiment, the substrate 2 can be made of metal, ceramic, or plastic. As a metal, stainless steel alloys, cobalt-chromium alloys, titanium, titanium alloys, etc., can be used. As a titanium alloy, alloys containing at least one of aluminum, tin, zirconium, molybdenum, nickel, palladium, tantalum, niobium, vanadium, platinum, etc., can be used. As a ceramic, alumina, zirconium oxide, alumina-zirconia composite ceramics, etc., can be used. As a plastic, polyethylene, fluoropolymers, epoxy resins, polyetheretherketone (PEEK) resins, phenolic resins, etc., can be used.

[0041] The anterior surface 3 is formed as a slightly thickened wall in the anteroposterior direction, with the central portion bulging forward (at the anterior end) to form a convex curved surface. In addition, the anterior surface 3 is formed into a cone shape in which the width decreases towards the anterior end. With this shape, the anterior surface 3 is formed into a cone shape, which facilitates the insertion of the spinal implant 1 into the intervertebral space.

[0042] The rear surface 4 is formed by a flat surface. For example... Figure 2 As shown, a screw hole 4a is formed in the central portion of the rear surface 4, extending from the rear surface 4 to the cavity portion 7 in the front-rear direction. This screw hole 4a engages with a threaded portion 101 formed at the front end of the rod portion of the retaining device 100 for retaining the spinal implant 1. That is, the retaining device 100, as an embodiment, also functions as a locking device, and the threaded portion 101 can also engage with the screw hole 4a, which functions as a locking portion.

[0043] In addition, such as Figure 2 As shown, a recess 4b is formed in the central portion of the rear surface 4 in the vertical direction. The front end of the rod of the retaining device 100 abuts against this recess 4b (see reference). Figure 7 It should be noted that as long as the threaded portion 101 can be engaged, the threaded hole 4a may not be through. Furthermore, the threaded portion 101 of the retaining device 100 can be rotated independently of the front end of the rod. By rotating only the threaded portion 101, the retaining device 100 can be attached to or detached from the spinal implant 1 while the front end of the rod of the retaining device 100 is abutting against the recess 4b.

[0044] It should be noted that the spinal implant 1 may also be held in the retaining device 100 without the aid of the screw hole 4a. For example, the retaining device 100 may also have a mechanism for holding the spinal implant 1, and hold the spinal implant 1 by holding it.

[0045] Furthermore, the base 2 is formed to decrease in size from the front surface 3 to the rear surface 4; in other words, the cross-sectional area of ​​the surface perpendicular to the front-rear direction (the area of ​​the region surrounded by the outer edge) increases from the rear surface 4 towards the front surface 3. Moreover, as the base 2 moves from the front surface 3 to the rear surface 4, the change in width in the left-right direction is smaller than the change in height in the up-down direction. It should be noted that, more specifically, in this embodiment, when comparing the rear surface 4 and the front surface 3, the maximum value of the length along the left-right direction is constant, while the maximum value of the length along the up-down direction increases. By adopting this shape, it is possible to adapt to the shape of the human vertebral body.

[0046] The right side 5 and the left side 6 are respectively formed to extend in the front-to-back direction and are positioned opposite each other in the left-to-right direction. For example... Figure 2 As shown, through holes 5a and 6a are formed in the central portion of the right side 5 and left side 6, respectively. These holes 5a and 6a facilitate blood flow near the spinal implant 1 when it is inserted and fixed between the vertebrae.

[0047] like Figure 2 , Figure 3 , Figure 5 As shown, a cavity 7 is formed in the spinal implant 1, extending vertically from the upper surface 8 to the lower surface 9. This cavity 7 is filled with bone-forming material.

[0048] like Figures 2 to 4 As shown, a plurality of protruding teeth 10 are formed on the upper surface 8, protruding upward from the upper surface 8 and extending in the left-right direction within the surface of the upper surface 8. Similarly, a plurality of protruding teeth 10 are formed on the lower surface 9, protruding downward from the lower surface 9 and extending in the left-right direction within the surface of the lower surface 9. That is, the plurality of protruding teeth 10 are configured as teeth protruding from each of the surfaces 8 and 9.

[0049] It should be noted that, in this case, as mentioned above, "the base 2 is formed to shrink from the front surface 3 to the rear surface 4" means that the height of the apex of the protruding tooth portion 10 along the vertical direction tends to decrease towards the rear.

[0050] Furthermore, the plurality of protruding teeth 10 disposed on the upper surface 8 and the plurality of protruding teeth 10 disposed on the lower surface 9 can also be positioned corresponding to each other in the vertical direction. That is, a particular protruding tooth 10 disposed on the lower surface 9 can also be located in the downward direction of a particular protruding tooth 10 disposed on the upper surface 8.

[0051] The protruding teeth 10 are formed such that the slope in the forward direction is gentler (smaller) than the slope in the backward direction. When the upper surface 8 and lower surface 9 of the spinal implant 1 are in contact with the vertebra 50, the spinal implant 1 is easy to move forward and difficult to move backward.

[0052] Thus, by having the toothed portion 10, the positional displacement of the spinal implant 1 can be suppressed, and back out can also be suppressed (described later).

[0053] In addition, the vertical height of the front surface 3 is smaller than the vertical height of the protruding tooth portion 10, and the rear surface 4 exists inside the extension line of the imaginary line connecting the vertices of the protruding tooth portion 10.

[0054] Furthermore, the imaginary line connecting the vertices of the multiple protruding teeth 10 can also be a curve. Additionally, when the imaginary line connecting the vertices of the multiple protruding teeth 10 is a curve, the vertex of the curve (imaginary curve) can also be located on the front surface 3 side. That is, the distance between the vertex of the imaginary curve and the front surface 3 can be smaller than the distance between the vertex of the imaginary curve and the rear surface 4.

[0055] Furthermore, in the spinal implant 1 of this embodiment, there is no coating that includes calcium phosphate-based material and antibacterial agent in the overall configuration of the spinal implant 1, but rather a first region with a coating and a second region exposed from the coating.

[0056] The identification of the first region, which is coated with a film containing calcium phosphate-based materials and an antibacterial agent, and the second region exposed from the film can be performed by elemental analysis of the surface of each region. Elemental analysis methods can be performed, for example, by surface element mapping using an energy-dispersive X-ray diffraction (EDX) apparatus, which is a common accessory to a scanning electron microscope (SEM). Alternatively, surface analysis methods such as X-ray photoelectron spectroscopy, Auger electron spectroscopy, and secondary ion mass analysis can also be used. Furthermore, chemical analysis can be performed on the sample obtained by mechanically removing the surface of each region to identify the elements. On the surface of the first region, phosphorus, calcium, and antibacterial components were detected. On the surface of the second region, elements constituting the substrate were detected, but phosphorus, calcium, antibacterial components, etc., were either undetectable or below noise levels.

[0057] For example, the area of ​​the screw hole 4a (second region) on the surface of the spinal implant 1 is not covered, and the covering is only provided in the area outside the screw hole 4a (first region). In this case, the area of ​​the screw hole 4a is directly exposed to the substrate surface of the spinal implant 1. The second region can be the entire screw hole 4a or a part of the screw hole 4a. In addition, the second region is not limited to the screw hole 4a and can also be other parts of the spinal implant 1. It should be noted that the part of the substrate surface exposed from the covering (second region) can be exposed only from the covering, or it can be formed with a membrane or layer different from the covering.

[0058] Therefore, the spinal implant 1 can enjoy the advantages of the covered membrane while reducing the risk of the membrane peeling off and being introduced into the body.

[0059] Furthermore, regarding the membrane covering the spinal implant 1, the membrane thickness at the boundary between the upper surface 8 and the right side surface 5 or the left side surface 6, or at the boundary between the lower surface 9 and the right side surface 5 or the left side surface 6, can be thicker than the membrane thickness in other areas. That is, it is possible to form a thicker membrane covering at the corners of the substrate.

[0060] Furthermore, regarding the membrane covering the cavity portion 7 of the spinal implant 1, the membrane thickness at the edge of the opening of the cavity portion 7 may be greater than the membrane thickness on the inner surface of the cavity portion 7. Alternatively, the membrane may be formed in such a way that the membrane thickness decreases from the opening of the cavity portion 7 towards the inner side.

[0061] [Matrix Preparation]

[0062] The manufacturing method of the spinal implant 1 will be described. First, a substrate 2 is prepared for manufacturing the spinal implant 1. The substrate 2 can be formed, for example, by machining a block such as a round bar made of metal. Through machining, a substrate having various constituent elements such as a front surface 3, a rear surface 4, an upper surface 8, a lower surface 9, a right side surface 5, a left side surface 6, a cavity 7, and holes 5a and 6a can be prepared. That is, in the substrate that becomes the spinal implant 1, a cavity 7 extending through the vertical direction is provided, holes 5a and 6a are provided on the left and right sides, and a screw hole 4a is provided on the rear surface (the process of forming the engaging part, the hole forming process). It should be noted that the substrate 2 can also be formed by machining a block of ceramic or resin, or it can be formed by a method different from machining.

[0063] [Lamination Method]

[0064] Next, the coating method for the spinal implant 1 will be described. In this embodiment, the spinal implant 1 is coated by spraying a material containing a calcium phosphate-based material and an antibacterial agent onto a substrate. The antibacterial agent is, for example, silver, and the silver concentration in the sprayed coating is, for example, 0.05% to 3.00% by weight. As the calcium phosphate-based material, one or more mixtures selected from the group consisting of hydroxyapatite, α-calcium triphosphate, β-calcium triphosphate, and calcium tetraphosphate can be used.

[0065] Examples of spray coating methods for forming coatings containing calcium phosphate-based materials include flame spraying, high-speed flame spraying, plasma spraying, and cold spraying. For instance, in flame spraying, a gaseous flame of oxygen and a combustible gas is used as a heat source to molten or near-molten the spraying material, which is then blown onto the surface of the base material to form a coating. In typical flame spraying, the spraying temperature is approximately 2700°C, and the spraying speed is Mach 0.6. Spraying conditions can be, for example, introducing the spraying powder into a gas torch containing 50 psi of oxygen and 43 psi of acetylene gas using 100 psi of dry air, and performing spraying at a distance of 60–100 mm.

[0066] The thickness of the spray-coated film is 5 to 100 μm, preferably 20 to 40 μm. This is because if it is 5 μm or more, it can cover the entire area of ​​the spray-coated part. In addition, if it is less than 100 μm, the adhesion strength of the film will not decrease due to residual stress during spraying.

[0067] In this embodiment, the spray-coating of a calcium phosphate-based material containing antibacterial material is formed by blowing powdered coating material onto a base material (substrate) in a molten (or semi-molten) state, followed by cooling, solidification, and deposition. Therefore, the spray-coated film can also be referred to as a spray layer or coating.

[0068] The resulting sprayed coating can also be heat-treated. This is because, in this case, the increased crystallinity of the calcium phosphate-based material improves the stability of the coating. The heat treatment is performed at 10... -2 The test is conducted at a reduced pressure below Pa for 0.5 to 7 hours within a temperature range of 400 to 1000°C. Preferably, the test is conducted at a temperature range of 550 to 850°C for 1 to 5 hours.

[0069] Alternatively, the sprayed coating can be hydrated after heat treatment. Hydration transforms oxyapatite into hydroxyapatite, stabilizing the leaching properties of silver ions. Hydration is a process of adding water molecules to the substance, which can be performed, for example, by immersing the substance in water at 60–100°C for 10–60 minutes.

[0070] The silver concentration in the spray-coated film can be adjusted by varying the amount of silver raw material mixed with the calcium phosphate-based material used as the spray coating material. The silver concentration in the spray-coated film is 0.05 wt% to 3.00 wt%, preferably 0.05 wt% to 2.50 wt%, more preferably 0.05 wt% to 1.00 wt%, and even more preferably 0.1 wt% to 1.00 wt%. This is because if it is 0.05 wt% or more, the antibacterial properties become sufficient. Furthermore, if it is 3.00 wt% or less, the burden on biological tissues can be suppressed.

[0071] The coating process for the spinal implant 1 is as follows: A coating comprising a calcium phosphate-based material and an antibacterial agent is locally formed on the substrate (coating formation process). It should be noted that the area on the substrate where the coating comprising the calcium phosphate-based material and the antibacterial agent is locally formed is the first region, and the area of ​​the substrate without a coating is the second region. In this coating formation process, the coating is formed with a screw inserted into the screw hole 4a, and then the screw is removed. Thus, a coating can be formed except for the screw hole 4a. When the second region is configured as a whole of the screw hole 4a, the screw hole 4a can be completely filled with the screw used in the coating formation process. The screw used in the coating formation process is, for example, configured to penetrate the screw hole 4a. It should be noted that, in the case of roughening, roughening can be performed before forming the coating (roughening process).

[0072] The methods for forming the coating are not limited to spraying methods such as flame spraying, high-speed flame spraying, and plasma spraying. Physical vapor deposition methods such as sputtering, ion plating, ion beam evaporation, and ion stirring, or wet coating methods such as sol-gel methods can also be selected.

[0073] Alternatively, the coating can be directly applied to the substrate 2 using the methods described above, or it can be applied via an intermediate layer as follows. That is, the coating can be formed on the substrate surface by methods such as coating, plating, spraying, or vapor deposition, and this coating can be used as an intermediate layer to further form the aforementioned calcium phosphate-based material coating. Furthermore, additive manufacturing can also be used as a method for forming the intermediate layer.

[0074] The intermediate layer can also be metal, polymer, or ceramic. For example, after using PEEK resin as a matrix and forming a titanium intermediate layer on the desired surface of the matrix, a coating containing calcium phosphate-based materials and an antibacterial agent can be formed on the surface of the intermediate layer.

[0075] [Insertion method for intervertebral insertion]

[0076] Next, the steps for inserting the spinal implant 1 of this embodiment into the intervertebral space will be described.

[0077] First, when the surgeon inserts the spinal implant 1 into the intervertebral space, the spinal implant 1 is fitted into a retainer 100 for holding the spinal implant 1. Specifically, with the rod of the retainer 100 clamped into the recess 4b of the spinal implant 1, the threaded portion of the retainer 100 is screwed into the threaded hole 4a of the spinal implant 1. Thus, the spinal implant 1 is positioned relative to the retainer 100, and the spinal implant 1 is held. It should be noted that the cavity 7 of the spinal implant 1 is filled with bone-forming material.

[0078] Next, the surgeon inserts the spinal implant 1 into the intervertebral space. Specifically, the surgeon inserts the anterior surface 3 sides of the spinal implant 1 from the dorsal side of the spine, relative to the intervertebral space where the bone and intervertebral discs that were compressing the nerves have been removed. Then, after positioning the spinal implant 1 on one side (e.g., the right side) of the adjacent vertebra 50, the retaining device 100 is removed from the spinal implant 1, thereby positioning the spinal implant 1 on the right side of the intervertebral space. If the placement of the spinal implant 1 is shallower than the preoperatively intended position, the implant 1 is driven in using an insertion device (impactor) to adjust the placement. Similarly, the surgeon positions the spinal implant 1 on the left side of the adjacent intervertebral space.

[0079] The surgeon then places a metal rod (not shown) between adjacent vertebrae and fixes it to each vertebra 50. This allows adjacent vertebrae 50 to be fixed together. After surgery, the adjacent vertebrae 50 are securely fixed by fusing the bone-forming material filling the cavity 7 with the bones of the upper and lower vertebrae 50.

[0080] However, problems sometimes arise, such as in the initial state where the spinal cage is fixed between the vertebrae, or when the bone-forming material filling the cavity has not fully fused with the vertebrae. Disengagement refers to the spinal implant 1, positioned at a predetermined location between the vertebrae, shifting towards the patient's dorsal (posterior) side.

[0081] In the spinal implant 1 of this embodiment, the posterior surface is steeper than the anterior surface in terms of the inclination of the protruding teeth 10 provided on the upper surface 8 and the lower surface 9. As a result, the spinal implant 1 is difficult to move posteriorly, and withdrawal of the spinal implant 1 can be prevented.

[0082] [Roughening]

[0083] A portion of the surface of the spinal implant 1 can also be roughened to create a roughened surface. For example, the upper surface 8 and lower surface 9 of the spinal implant 1 can be roughened. Roughening can be performed, for example, by using at least one of spraying and shot peening. As the spraying material, materials exemplified as the material of the substrate 2 can be used. As the shot peening treatment, sandblasting and the like can be used. Alternatively, roughening can be performed by using a 3D printer or similar process to form a porous structure on the surface of the spinal implant 1. By roughening the upper surface 8 and lower surface 9, the roughened portion comes into contact with the spine, thereby improving the fixation of the spinal implant 1 to the spine.

[0084] It should be noted that for the formation of a rough surface, roughening can be performed before forming the coating. Then, the coating can be formed on the rough surface afterward.

[0085] The rough surface is formed by roughening each surface of the substrate. Specifically, the upper surface 8 and the lower surface 9 can be roughened in a first direction to form a rough surface, and the right side surface 5 and the left side surface 6 can be roughened in a second direction to form a rough surface. Furthermore, the front surface 3 can then be roughened in a third direction (front-back direction) that intersects with the first and second directions to form a rough surface.

[0086] It should be noted that, depending on the shape of the front surface 3, sometimes a sufficiently rough surface can also be formed on the front surface 3 by roughening the upper surface 8, lower surface 9, right side surface 5, and left side surface 6. In this case, the roughening treatment of the front surface 3 can be omitted.

[0087] Alternatively, rough surfaces can be formed on the inner surfaces of the cavity 7 and the holes 5a and 6a respectively.

[0088] It should be noted that, depending on the shape of the cavity 7, the hole 5a, and 6a and the direction of spraying or sandblasting, while spraying the outer surface (upper surface 8, lower surface 9, right side 5, and left side 6) of the coating, spraying can also be performed on the inner surface of the cavity 7, the hole 5a, and 6a to form a coating including the first region and the second region.

[0089] [Variation Example]

[0090] In addition, in this embodiment, the retaining device 100 is screwed onto the spinal implant 1 using threads, and the retaining device 100 retains the spinal implant 1, but the retention of the spinal implant 1 by the retaining device 100 is not limited to threads.

[0091] For example, the spinal implant 1 can be held in place by providing a locking mechanism including a recess or a protrusion in the base 2 of the spinal implant 1, and by engaging a portion of the locking and holding device 100 with the locking mechanism. Specifically, the mechanism could be as follows: a hole with an internal diameter larger than the opening diameter is provided in the base; a mechanism for variable outer diameter is provided at the front end of the holding device; the device is inserted into the hole in the base with the outer diameter of the front end reduced; and then the outer diameter is increased inside the hole to achieve locking. That is, the holding device 100 can also function as a locking device, and the hole (locking portion) engaging with the holding device has a locking mechanism that locks the holding device 100 to the base 2. It should be noted that the spinal implant can also be held in place by using a holding device that clamps a portion of the base.

[0092] In this embodiment, the area where the second region exposed from the covering is defined as the area of ​​the screw hole 4a. Here, the entire area of ​​the screw hole 4a along the depth direction can be defined as the second region, but only a portion of the area can be defined as the second region. However, it is preferable to define the area on the side where the retaining device 100 is inserted as the second region. Furthermore, the second region is not limited to the area of ​​the screw hole 4a; it can also be the area of ​​the aforementioned locking mechanism or engaging portion. Moreover, it is not limited to these areas; the area that contacts a portion of the retaining device 100 when the spinal implant 1 is held using the retaining device 100, or the area that slides with a portion of the retaining device 100, can also be defined as the second region. It is preferable to define the area other than the areas described above as the first region where the covering is disposed, but it is also possible to provide a second region exposed from the covering outside the areas described above.

[0093] In this embodiment, a spinal implant 1 inserted between adjacent vertebrae is exemplified as the spinal implant of the present invention. However, the spinal implant of the present invention is not limited to the spinal implant 1 described above. For example, spinal rods (components for fixing the spine to a certain shape) and spinal screws (components for screwing the spinal rod into the vertebrae to fix the spinal implant 1 to the spine) for fixing the spinal implant 1 between the vertebrae are also included in the spinal implant of the present invention. In this case, it is preferable to set the second area exposed from the diaphragm as an area where the components are in contact with each other (e.g., the spinal rod and the spinal screw) or slide.

[0094] [Implementation Method 2]

[0095] Other embodiments of the present invention will be described below. It should be noted that, for ease of explanation, components having the same function as those described in the above embodiments are marked with the same reference numerals, and their descriptions are not repeated. That is, structures not mentioned in this embodiment are the same as those in Embodiment 1 described above.

[0096] [Structure of spinal implant 1]

[0097] In the spinal implant 1 of this embodiment, the entire spinal implant 1 may not be configured with a membrane containing calcium phosphate material and antibacterial agent, but may include a first region with a membrane and a sixth region with a membrane thickness smaller than that of the first region.

[0098] In this embodiment, for example, the anterior surface 3, a portion of the posterior surface 4 (excluding the screw hole 4a and the recess 4b), the upper surface 5, the lower surface 9, the right side surface 5, and the left side surface 6 of the spinal implant 1 are a first region where a membrane is disposed. Additionally, the inner surfaces of the holes 5a and 6a, the inner surface of the cavity 7, and the recess 4b are a sixth region where a membrane with a thickness smaller than that of the first region is disposed.

[0099] Thus, the first region can be the outer peripheral surface of the substrate 2, and the sixth region can be the inner surface of the cavity 7 and the inner surfaces of the holes 5a and 6a. As a result, the spinal implant 1 can enjoy the advantages of being covered with a membrane while reducing the total amount of membrane compared to a case where the entire spinal implant 1 is covered with a membrane.

[0100] Furthermore, by having a sixth region with a membrane thickness smaller than that of the first region, the membrane of the sixth region can be formed more easily than that of the first region, thereby improving the manufacturing efficiency of the spinal implant 1.

[0101] In addition, the spinal implant 1 also includes a third region where the membrane thickness of the covering is smaller than that of the sixth region, or where it is not covered (exposed from the covering). It should be noted that the third region corresponds to the second region in Embodiment 1 described above. In this embodiment, the screw hole 4a is the third region without a covering. In this case, the area of ​​the screw hole 4a is directly exposed to the substrate surface of the spinal implant 1. The third region can be the entire screw hole 4a or a part of the screw hole 4a. Furthermore, the third region is not limited to the screw hole 4a and can also be other parts of the spinal implant 1. It should be noted that the portion of the substrate surface exposed from the covering (the third region) can be exposed from the covering, or it can have a membrane or layer different from the covering.

[0102] [Lamination Method]

[0103] The coating process for the spinal implant 1 is as follows. The coating is formed in a manner with different film thicknesses (coating formation process). Thus, with respect to the coating, a first region and a sixth region with different film thicknesses can be formed. The coating can be formed by spray coating on each surface of the substrate 2. When formed by spray coating, the thickness of the coating on the substrate 2 can be changed, for example, by adjusting the spray coating time, spray coating direction, structure of the spray coating material, spray coating temperature, and other spray coating conditions. For example, increasing the thickness of the coating on the substrate 2 can be achieved by extending the spray coating time, and decreasing the thickness of the coating on the substrate 2 can be achieved by shortening the spray coating time.

[0104] Specifically, a coating can be formed by spraying on the upper surface 8 and the lower surface 9 from a first direction, and a coating can be formed on the right side surface 5 and the left side surface 6 from a second direction. Furthermore, a coating can then be formed on the front surface 3 by spraying on a third direction (front-back direction) intersecting with the first and second directions. In this way, a first region with a coating can be formed on each surface of the substrate 2.

[0105] It should be noted that, depending on the shape of the front surface 3, sometimes a coating of sufficient thickness can also be formed on the front surface 3 by spraying the upper surface 8, lower surface 9, right side surface 5, and left side surface 6. In this case, the spraying of the front surface 3 can be omitted.

[0106] Furthermore, a coating is formed on the inner surfaces of the cavity portion 7 and the holes 5a and 6a. For the spraying of the cavity portion 7 and the holes 5a and 6a, by shortening the irradiation time compared to the case where a coating is formed in the first region, a sixth region with a smaller film thickness than the first region can be formed. Additionally, the formation of the sixth region can also be achieved, for example, by reducing the amount of sprayed material compared to the case where a first region is formed.

[0107] It should be noted that, depending on the shape of the cavity portion 7, the holes 5a and 6a, and the spraying direction, spraying can be performed on the outer surface of the coating (upper surface 8, lower surface 9, right side surface 5, and left side surface 6) while simultaneously spraying onto the inner surface of the cavity portion 7, the holes 5a and 6a, thus forming a coating including a first region and a sixth region. That is, by considering the shape of the substrate 2 and the amount of rewinding of the spraying material, the film thickness of the first region and the film thickness of the sixth region can be formed by spraying the substrate 2.

[0108] Furthermore, a coating is formed on the inner surface of the recess 4b of the rear surface 4. For the spraying of the recess 4b, by shortening the irradiation time compared to the case where the coating is formed in region 2, a coating in a third region with a smaller film thickness than the sixth region can be formed. Additionally, the formation of the third region can also be achieved, for example, by reducing the amount of sprayed material compared to the case where the sixth region is formed. It should be noted that the third region can also be formed simultaneously with the first and sixth regions depending on the spraying conditions. Furthermore, the rear surface 4, excluding the recess 4b, can be either the first or sixth region of the coating.

[0109] It should be noted that in the coating formation process, the coating is formed with the screw for the coating formation process inserted into the screw hole 4a, and then the screw is removed. This allows the coating to be formed in all areas except for the screw hole 4a. When the sixth region is configured as a whole with the screw hole 4a, the screw hole 4a can be completely filled with the screw for the coating formation process. For example, the screw for the coating formation process can be configured to pass through the screw hole 4a. This also allows the formation of a third region of coating. It should be noted that in the case of roughening, roughening can be performed before forming the coating (roughening process).

[0110] [Roughening]

[0111] The rough surface is formed by roughening each surface of the substrate. Specifically, the upper surface 8 and lower surface 9 can be roughened in a first direction to form a rough surface, and the right side surface 5 and left side surface 6 can be roughened in a second direction to form a rough surface. Furthermore, the front surface 3 can then be roughened in a third direction (front-back direction) intersecting the first and second directions to form a rough surface. In this way, a fourth roughened region can be formed on each surface of the substrate 2.

[0112] It should be noted that, depending on the shape of the front surface 3, sometimes a sufficiently rough surface can also be formed on the front surface 3 by roughening the upper surface 8, lower surface 9, right side surface 5, and left side surface 6. In this case, the roughening treatment of the front surface 3 can be omitted.

[0113] Furthermore, the inner surfaces of the cavity portion 7 and the holes 5a and 6a are roughened. By shortening the processing time compared to the case where a roughened fourth region is formed, the roughening process of the cavity portion 7 and the holes 5a and 6a can create a roughened fifth region with a smaller roughness than the fourth region. Additionally, the formation of the roughened fifth region can also be achieved, for example, by reducing the amount of plating material or sandblasting compared to the case where a fourth region is formed.

[0114] It should be noted that, depending on the shape of the cavity 7, the hole 5a, and 6a and the direction of spraying or sandblasting, while spraying the outer surface (upper surface 8, lower surface 9, right side 5, and left side 6) of the coating, spraying can also be performed on the inner surface of the cavity 7, the hole 5a, and 6a to form a coating including the first region and the sixth region.

[0115] It should be noted that the aforementioned first region comprises the anterior surface 3, posterior surface 4, upper surface 8, lower surface 9, right side surface 5, and left side surface 6 of the spinal implant 1, and therefore can overlap with the fourth region. Furthermore, the sixth region comprises the inner surface of the cavity portion 7 and the inner surfaces of the holes 5a and 6a, and therefore can overlap with the fifth region.

[0116] [Variation Example]

[0117] In this embodiment, the third region exposed from the covering is described as the region of the screw hole 4a. Here, the entire region of the screw hole 4a along the depth direction can be designated as the third region, but only a portion of the region can be designated as the third region. However, it is preferable to designate the region on the side where the retaining device 100 is inserted as the third region. Furthermore, the third region is not limited to the region of the screw hole 4a; it can also be the region of the aforementioned locking mechanism or engaging portion. Moreover, it is not limited to these regions; the region that contacts a portion of the retaining device 100 when the spinal implant 1 is held using the retaining device 100, or the region that slides with a portion of the retaining device 100, can also be designated as the third region. Preferably, the region other than those described above is designated as the first or sixth region where the covering is disposed, but it is also possible to provide a third region exposed from the covering outside of the regions described above.

[0118] In this embodiment, the inner surfaces of the holes 5a and 6a, the inner surface of the cavity 7, and the recess 4b are designated as the sixth region, but the recess 4b could also be the first region. Alternatively, the surface other than the screw hole 4a that does not face outwards could be designated as the sixth region.

[0119] In this embodiment, a spinal implant 1 inserted between adjacent vertebrae is exemplified as the spinal implant of the present invention. However, the spinal implant of the present invention is not limited to the spinal implant 1 described above. For example, spinal rods (components for fixing the spine to a certain shape) and spinal screws (components for screwing the spinal rods into the vertebrae to fix them to the spine) are also included in the spinal implant of the present invention. In this case, it is preferable that the third region exposed from the diaphragm is set as a region where the components (e.g., the spinal rods and spinal screws) are in contact with or slide against each other.

[0120] This invention is not limited to the embodiments described above, and various modifications can be made within the scope of the technical solutions shown. Embodiments obtained by appropriately combining the technical solutions disclosed in different embodiments are also included within the technical scope of this invention. Furthermore, by combining the technical solutions disclosed in the embodiments, new technical features can be formed.

[0121] 〔Summarize〕

[0122] A spinal implant according to one aspect of the present invention comprises: a substrate; and a membrane disposed on the substrate and comprising a calcium phosphate-based material and an antibacterial agent, wherein the surface of the substrate has a first region on which the membrane is disposed and a second region exposed from the membrane.

[0123] The calcium phosphate-based material in the coating improves osteoconductivity and bone fixation. The antibacterial agent in the coating reduces bacterial adhesion and proliferation.

[0124] Furthermore, according to the aforementioned structure, the second area of ​​the substrate exposed from the cover can be maintained while the spinal implant is inserted into the body during surgery. Therefore, the cover is less likely to peel off from the holding portion when the spinal implant is inserted or when the retaining device is removed. Consequently, compared to covering the entire surface of the substrate, the risk of the cover peeling off and being introduced into the body can be reduced.

[0125] In one embodiment of the spinal implant of the present invention, the spinal implant may also include a locking portion disposed in the second region and capable of locking with a locking device.

[0126] According to the structure described, the second region has a locking portion that can engage with the locking device, thus preventing the coating from peeling off during engagement.

[0127] In one embodiment of the spinal implant of the present invention, the engaging portion may have a engaging mechanism including a recess or a protrusion that engages the engaging device with the base.

[0128] According to the structure described, the locking device can be locked to the substrate without the use of adhesives, magnetism, etc., by a locking mechanism including recesses or protrusions.

[0129] In one embodiment of the spinal implant of the present invention, the engaging portion may have a screw hole.

[0130] According to the structure described, spinal implants can be easily installed into the retainer by using screw holes, and can also be easily removed.

[0131] In one embodiment of the present invention, the spinal implant may have a roughened surface portion, and the covering membrane may cover at least a portion of this roughened surface portion.

[0132] According to the structure described, by bringing the rough surface into contact with the spine, the fixation of the spinal implant to the spine can be improved.

[0133] In a spinal implant according to one aspect of the present invention, it is preferred that the covering is disposed directly on the substrate.

[0134] According to the described structure, the structure of spinal implants becomes simple, thus enabling the reduction of manufacturing costs.

[0135] One aspect of the present invention provides a method for manufacturing a spinal implant, comprising a coating forming step of locally forming a coating comprising a calcium phosphate-based material and an antibacterial agent on a substrate.

[0136] In one embodiment of the present invention, the method for manufacturing a spinal implant may include a step of forming a locking portion on the substrate that can engage with a locking device before the film forming step, wherein the film is formed in addition to the locking portion in the film forming step.

[0137] In one embodiment of the present invention, the method for manufacturing a spinal implant may include a hole forming step that forms a screw hole in the substrate before the coating forming step, wherein the coating is formed in the substrate in addition to the screw hole during the coating forming step.

[0138] In one embodiment of the present invention, the method for manufacturing a spinal implant may include a roughening step of roughening a portion of the substrate to form a roughened surface before the coating formation step, wherein the coating is formed in such a way that it covers at least a portion of the roughened surface.

[0139] In one aspect of the manufacturing method of a spinal implant according to the present invention, the roughening process may be performed by at least one of spraying and shot peening.

[0140] One aspect of the present invention provides a spinal implant comprising: a substrate; and a covering disposed on the substrate and comprising a calcium phosphate-based material and an antibacterial agent, the covering having a first region and a sixth region having a thickness smaller than the first region.

[0141] The calcium phosphate-based material in the coating improves osteoconductivity and bone fixation. Additionally, the antibacterial agent in the coating reduces bacterial adhesion and proliferation. On the other hand, antibacterial metal agents are costly, so their quantity is preferred to be as low as possible. Furthermore, according to the structure described, the coating thickness is thinner in a portion of the area than in other areas, thus reducing the total amount of antibacterial metal agent compared to not thinning it. This, for example, enables cost reduction.

[0142] In one embodiment of the present invention, the spinal implant may further include a first through portion extending through the base in a first direction.

[0143] According to the structure described, bone-forming material can be filled into the first through portion, thereby facilitating the connection between the spinal implant and the vertebra.

[0144] In one embodiment of the present invention, the spinal implant may have the first region located on the outer peripheral surface of the substrate, and the sixth region located on the inner surface of the first through portion.

[0145] According to the structure described above, the film thickness of the coating on the inner surface of the first through portion is smaller than the film thickness of the coating on the outer peripheral surface, thus maintaining the antibacterial properties of the area that is likely to be in direct contact with the vertebra and reducing the total amount of silver contained in the antibacterial agent.

[0146] In one embodiment of the present invention, the spinal implant may have a third region with a thickness smaller than that of the sixth region, and the first region and the third region are located on the outer peripheral surface of the substrate.

[0147] In the described structure, if the third region is designated as a retaining portion for holding the spinal implant, it is possible to suppress the peeling of the covering that occurs while holding the spinal implant. Therefore, according to the described structure, it is possible to suppress the peeling of the covering that occurs while holding the spinal implant and the subsequent re-entry into the body.

[0148] In one embodiment of the present invention, the spinal implant may have a fourth region on its surface and a fifth region with a surface roughness smaller than that of the fourth region.

[0149] According to the structure described, the surface roughness of a specified area of ​​the substrate can be reduced as needed.

[0150] In one embodiment of the spinal implant of the present invention, the first region may overlap with the fourth region.

[0151] Based on the structure described above, regions belonging to both the first and fourth regions can be set.

[0152] In one embodiment of the present invention, the sixth region may overlap with the fifth region.

[0153] Based on the structure described, regions belonging to both the sixth and fifth regions can be set.

[0154] In one embodiment of the present invention, the spinal implant may further include a second through portion that penetrates the base in a second direction that intersects the first direction.

[0155] According to the structure described, blood flow can be promoted by means of the second through section.

[0156] In one embodiment of the spinal implant of the present invention, the second through portion may have a plurality of through holes arranged separately from each other.

[0157] According to the structure described, blood flow can be promoted by means of multiple through holes.

[0158] In one embodiment of the spinal implant of the present invention, the sixth region may be located on the inner surface of the second through portion.

[0159] According to the structure described above, the thickness of the membrane covering the inner surface of the second through section, which is less likely to come into direct contact with the vertebra, can be reduced.

[0160] A method for manufacturing a spinal implant according to one aspect of the present invention includes: a step of preparing a substrate; and a step of forming a coating on the substrate, the coating comprising a calcium phosphate-based material and an antibacterial agent, and having a first region and a sixth region with a thickness smaller than the first region.

[0161] In a method for manufacturing a spinal implant according to one aspect of the present invention, in the step of forming the coating, a third region having a film thickness smaller than that of the sixth region is formed on the outer surface of the substrate.

[0162] In one aspect of the present invention, the method for manufacturing a spinal implant may include a step of forming a rough surface on at least a portion of the surface of the substrate before forming the covering.

[0163] In one aspect of the method for manufacturing a spinal implant according to the present invention, the membrane may be formed in a manner that covers at least a portion of the rough surface during the process of forming the membrane.

[0164] In one embodiment of the present invention, the method for manufacturing a spinal implant may also involve forming the rough surface by at least one of spraying and shot peening during the process of forming the rough surface.

[0165] Explanation of reference numerals in the attached figures

[0166] 1. Spinal implants

[0167] 2. Matrix

[0168] 3 Front Surface

[0169] 4. Back surface

[0170] 4a Screw hole (engaging part, locking mechanism)

[0171] 4b concave part

[0172] 5. Right side

[0173] 5a Hole

[0174] 6. Left side

[0175] 6a Hole

[0176] 7. Cavity

[0177] 8. Top surface

[0178] 9. Lower surface

[0179] 10. Teeth-like protrusions

[0180] 100 Retaining devices (locking devices)

[0181] 101 Threaded section.

Claims

1. A spinal implant, comprising: The matrix, which is composed of metallic materials; and A coating, disposed on the substrate, comprising a calcium phosphate-based material and an antibacterial agent, The surface of the substrate has a first region on which the coating is disposed and a second region exposed from the coating. The spinal implant has a first through portion extending through the base in a first direction. The inner surface of the first through portion is covered with the film. The coating also has a sixth region with a thickness smaller than that of the first region. The first region is located on the outer peripheral surface of the substrate. The sixth region is any one of the following regions: (a) The inner surface of the first through portion; (b) The inner surface of the second through portion penetrating the substrate in a second direction that intersects the first direction; and (c) A recess provided on the rear surface of the substrate.

2. The spinal implant according to claim 1, wherein, The spinal implant also has a locking portion disposed in the second region and capable of engaging with a locking device.

3. The spinal implant according to claim 2, wherein, The engaging portion has a locking mechanism including a recess or a protrusion that engages the engaging device with the base.

4. The spinal implant according to any one of claims 1 to 3, wherein, The second region has a screw hole.

5. The spinal implant according to claim 3, wherein, The locking mechanism includes: a hole with an internal diameter larger than the diameter of the opening in the second region; and a front end portion disposed in the locking device, capable of passing through the hole, and having an outer diameter that can be changed.

6. The spinal implant according to claim 3, wherein, The locking mechanism includes a clamping portion disposed in the locking device and capable of clamping the locking portion.

7. The spinal implant according to any one of claims 1 to 3, wherein, The substrate has a roughened surface area, and the coating covers at least a portion of this roughened surface area.

8. The spinal implant according to claim 7, wherein, The rough surface is disposed in the first region, and the surface roughness of the rough surface is greater than that of the second region.

9. The spinal implant according to any one of claims 1 to 3, wherein, The coating is directly applied to the substrate.

10. The spinal implant according to any one of claims 1 to 3, wherein, The spinal implant also has a second through portion that penetrates the matrix in a second direction that is an intersection with the first direction.

11. The spinal implant according to claim 10, wherein, The second through portion has a plurality of through holes arranged separately from each other.

12. The spinal implant according to any one of claims 1 to 3, wherein, The surface of the substrate has a fourth region and a fifth region with a surface roughness smaller than that of the fourth region.

13. The spinal implant according to claim 12, wherein, The first region overlaps with the fourth region.

14. A spinal implant, comprising: The matrix, which is composed of metallic materials; and A coating, disposed on the substrate, comprising a calcium phosphate-based material and an antibacterial agent, The coating has a first region and a sixth region with a film thickness smaller than the first region. The first region is located on the outer peripheral surface of the substrate. The sixth region is any one of the following regions: (a) The inner surface of the first through portion penetrating the substrate in the first direction; (b) The inner surface of the second through portion penetrating the substrate in a second direction that intersects the first direction; and (c) A recess provided on the rear surface of the substrate.

15. The spinal implant according to claim 14, wherein, The surface of the substrate has a fourth region and a fifth region with a surface roughness smaller than that of the fourth region, and the sixth region overlaps with the fifth region.

16. The spinal implant according to claim 14 or 15, wherein, The sixth region is located on the inner surface of the second through portion that penetrates the substrate in a second direction that is a direction intersecting the first direction.

17. A method for manufacturing a spinal implant, comprising the following steps: Prepare a substrate made of a metallic material, the substrate having a first through portion extending in a first direction; and A coating comprising a calcium phosphate-based material and an antibacterial agent is formed on the substrate. The coating has a first region located on the outer peripheral surface of the substrate and a sixth region with a thickness smaller than the first region. The sixth region is any one of the following regions: (a) The inner surface of the first through portion; (b) The inner surface of the second through portion penetrating the substrate in a second direction that intersects the first direction; and (c) A recess provided on the rear surface of the substrate.

18. The method for manufacturing a spinal implant according to claim 17, wherein, The method for manufacturing the spinal implant includes a step of forming a locking portion on the substrate, capable of engaging with a locking device, prior to forming the covering membrane. In the process of forming the coating, the coating is formed except for the engaging portion.

19. The method for manufacturing a spinal implant according to claim 17 or 18, wherein, The method for manufacturing the spinal implant includes a step of forming screw holes in the substrate prior to forming the overlay. In the process of forming the coating, the coating is formed on the substrate except for the screw holes.

20. The method of manufacturing a spinal implant according to claim 17 or 18, wherein, The method for manufacturing the spinal implant includes a step of forming a rough surface on at least a portion of the surface of the substrate before forming the overcoat.

21. The method for manufacturing a spinal implant according to claim 20, wherein, In the process of forming the coating, the coating is formed in such a way that it covers at least a portion of the rough surface.

22. The method for manufacturing a spinal implant according to claim 20, wherein, In the process of forming the rough surface, the rough surface is formed by at least one of spraying and shot peening.

23. The method for manufacturing a spinal implant according to claim 20, wherein, The process of forming the rough surface includes a process of forming the rough surface by additive manufacturing.

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