PEEK / Titanium composite spinal cage and its manufacturing method

Abstract

To provide a spinal cage made of a composite of PEEK and titanium, in which a titanium thin plate and a PEEK main body are not separated when implanted in a living body. [Solution] The spine cage is composed of a PEEK main body and a thin titanium plate attached to the upper and lower surfaces of the PEEK main body using a biocompatible adhesive. The upper and lower surfaces of the PEEK main body have been modified by a surface activation treatment, and the surface of the thin titanium plate that comes into contact with the PEEK main body has been roughened to form a fine uneven structure. The biocompatible adhesive applied between the upper and lower surfaces of the PEEK main body and the thin titanium plate penetrates into the recesses of the fine uneven structure and hardens, thereby joining the thin titanium plate to the PEEK main body by physical engagement via the layer of adhesive.

Description

[Technical field]

[0001] The present invention relates to a spinal cage made of a composite of PEEK and titanium and a method for manufacturing the same. [Background technology]

[0002] As the aging society progresses, the number of patients with age-related spinal diseases is increasing. A device called a spinal cage is used to treat spinal diseases such as herniated discs, spinal canal stenosis, and spinal compression fractures. By inserting the spinal cage between vertebrae, it is possible to promote bone regeneration and fusion while maintaining the intervertebral height, and fix the intervertebral discs located above and below the spinal cage.

[0003] Figure 3 shows the state in which the spinal cage is inserted into the intervertebral disc space between the vertebrae. Titanium, which is used in the spinal cage, is an excellent material that has excellent biocompatibility and the property of directly and firmly bonding with bone. However, because titanium is harder than bone, it has been pointed out that when the cage is inserted between the vertebrae and subjected to stress according to the movement of the patient's body, a gap occurs between the cage and the surrounding bones.

[0004] To solve this problem, PEEK (polyether ether ketone resin) is used as the material that makes up the cage. PEEK is biocompatible and has a hardness closer to that of bone than titanium, so it can deform in response to the stress it receives from the surrounding bone when implanted. However, unlike titanium, PEEK does not bond with bone, which makes it problematic as a material that makes up the cage. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Publication of JP2007-512874 Summary of the Invention [Problem to be solved by the invention]

[0006] To solve these two conflicting problems, a cage made of a composite of PEEK and titanium has been proposed. By constructing a cage from a composite of PEEK and titanium, the body has the hardness of PEEK and titanium bonds with bone, so it is expected that the above problems will be solved. However, PEEK resin has poor adhesion, and it is difficult to bond the PEEK surface to other materials using adhesives. In addition, titanium is a metal, and it is difficult to firmly bond metal and resin using adhesives. Therefore, there is an unavoidable risk that the adhesion will peel off from the titanium surface after the cage is implanted in the body, resulting in the separation of the titanium from the PEEK body.

[0007] To solve this problem, it has been proposed to coat the PEEK cage with titanium by plasma irradiation. There is little risk of the titanium plasma-coated PEEK cage peeling off from the PEEK. However, the bonding strength between the surface coated with titanium by plasma irradiation and the bone is inferior to that of a titanium cage, and it cannot be expected to achieve the same level of bonding with the bone as a titanium cage. Under these circumstances, a new spinal cage that has the hardness of PEEK but has excellent bonding strength with the bone was required. [Means for solving the problem]

[0008] In order to solve the above problems, the inventors of the present invention have intensively studied and have come up with the idea of ​​a method for bonding the resin surface of the PEEK body and the metal surface of the titanium plate using an adhesive without the risk of separation, which involves subjecting the resin surface of the PEEK body to a surface activation treatment to make it adhesive, and subjecting the metal surface of the titanium plate to a roughening treatment to form a fine uneven structure, and then applying a biocompatible adhesive to attach the titanium plate to the surface of the PEEK body. By firmly bonding the titanium thin plate to the PEEK body using this method, the stress received by the cage from the vertebrae can be directly transmitted to the PEEK body through the thin plate, and the stress received by the PEEK body, which has a hardness close to that of bone, can be absorbed.

[0009] Based on the above idea, the inventor of the present invention has proposed a spinal cage for use in interbody fusion surgery, which is made of a composite of PEEK and titanium, The spinal cage is configured by attaching titanium thin plates to the upper and lower surfaces of a roughly bullet-shaped PEEK body, The upper and lower surfaces of the PEEK body are modified by surface activation treatment, The surface of the titanium thin plate that comes into contact with the PEEK body is roughened to form a fine uneven structure, The PEEK body and the titanium thin plate are firmly joined to each other via a layer of biocompatible adhesive applied between them, which adheres to the surface of the PEEK body that has been subjected to the surface activation treatment, and the biocompatible adhesive penetrates into the recesses of the fine uneven structure formed on the surface of the titanium thin plate and hardens to form a physical fit, thereby firmly joining the titanium thin plate to the PEEK body via the layer of biocompatible adhesive; When the spinal cage is inserted between the vertebral bodies of a patient and implanted, the titanium thin plate attached to the PEEK body comes into contact with the surrounding vertebrae, and is bonded to the vertebrae without being separated from the PEEK body while receiving stress from the vertebrae as the patient moves. The inventors have now arrived at the invention of a spinal cage made of a composite of PEEK and titanium for use in the interbody fusion procedure.

[0010] The present inventors further disclose a method for manufacturing a PEEK / titanium composite spinal cage for use in an interbody fusion procedure, comprising the steps of: Prepare a roughly bullet-shaped PEEK body and two thin titanium plates to be attached to the top and bottom surfaces of the PEEK body. The upper and lower surfaces of the PEEK body are modified by surface activation treatment; The surfaces of the two titanium thin plates in contact with the PEEK body are roughened to form a fine uneven structure; The titanium thin plate is attached to the upper and lower surfaces of the PEEK body using a biocompatible adhesive, so that the layer of the biocompatible adhesive adheres to the upper and lower surfaces of the PEEK body that have been subjected to the surface activation treatment, and the biocompatible adhesive penetrates into the recesses of the fine uneven structure formed on the surface of the titanium thin plate and hardens, thereby forming a physical fit between the layer of the biocompatible adhesive and the surface of the titanium thin plate. The inventors have arrived at an invention of a method for manufacturing a spinal cage made of a composite of PEEK and titanium for use in the interbody fusion procedure.

[0011] The titanium thin plate preferably has a thickness of 0.5 to 5 mm, more preferably 1 to 3 mm.

[0012] Preferably, the biocompatible adhesive is an epoxy resin adhesive having excellent strength and rigidity.

[0013] Preferably, the titanium comprises titanium alloy 64 (Ti-6Al-4V).

[0014] Preferably, the surface activation treatment is an ozone treatment, an ultraviolet irradiation treatment, various discharge treatments, or a surface roughening treatment.

[0015] Preferably, the surface roughening treatment includes a chemical or physical treatment for forming a fine uneven structure on the surface of the titanium thin plate. The chemical treatment can be a method of immersing the plate in a caustic soda solution after degreasing, then in a nitric acid solution, followed by washing and drying, or anodizing, while the physical treatment can be the formation of an uneven structure by laser scanning.

[0016] Preferably, the upper and / or lower surface of the spine cage to which the titanium thin plate is attached is formed with an uneven shape, and the uneven shape of the upper and / or lower surface prevents the spine cage from moving back in the opposite direction to the insertion direction after the spine cage is inserted between the vertebral bodies. Effect of the Invention

[0017] The spine cage of the present invention has titanium thin plates attached to the upper and lower surfaces of the PEEK main body, so when the spine cage is inserted between the vertebrae of a patient and fixed, the vertebrae located above and below the cage come into contact with the titanium thin plates, and the stress received from the vertebrae is transmitted to the PEEK main body through the titanium thin plates, causing the PEEK main body to deform in response to the received stress. As a result, the composite spine cage of the present invention has a much smaller gap between the movement of the surrounding bones than when a titanium spine cage is used.

[0018] The spine cage of the present invention has a thin titanium plate firmly bonded to the surface of the PEEK body, so even if the spine cage inserted and implanted in the intervertebral disc space is subjected to stress from the surrounding vertebrae as the patient moves, the thin titanium plate will not peel off from the surface of the PEEK body.

[0019] The spine cage of the present invention has a thin titanium plate surface that contacts and bonds with the vertebrae, so that a superior bond can be obtained between the spine cage and the bone compared to a case where a PEEK body is coated with titanium.

[0020] In one embodiment of the spine cage of the present invention, a biocompatible epoxy resin adhesive is used to bond the PEEK body and the titanium thin plate, so that the cage can be used as a safe spine cage that can be implanted in the body.

[0021] The spine cage of the present invention has less gaps when implanted and moves with the surrounding bones, and the top and bottom surfaces of the spine cage come into contact with and fuse to the vertebrae via the thin titanium plates attached to the PEEK body, so it can achieve a better bond with the bone than conventional titanium spine cages. [Brief description of the drawings]

[0022] [Figure 1] Fig. 1(A) shows a perspective view of one embodiment of the spinal cage of the present invention. Fig. 1(B) shows the state before the titanium thin plate of one embodiment of the spinal cage of the present invention is attached to the PEEK body. [Diagram 2] Fig. 2(A) shows a state in which the titanium thin plate and the PEEK body of one embodiment of the spinal cage of the present invention are bonded together via an adhesive. Fig. 2(B) shows a state in which the hardened adhesive physically fits into the fine uneven structure formed on the titanium thin plate of one embodiment of the spinal cage of the present invention. [Diagram 3] FIG. 3 shows the spinal cage of the present invention inserted between the vertebrae of a patient. [Figure 4] FIG. 4 shows a flow chart of a method for manufacturing the spine cage of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0024] <Terminology> (1) Surface activation treatment In the present invention, surface activation treatment refers to a surface modification treatment applied to the resin surface of PEEK to give it adhesiveness. PEEK resin has poor adhesiveness, so in order to bond it with an adhesive, it is necessary to modify the resin surface by surface treatment. Surface activation treatments include chemical treatments (chemical treatment, solvent treatment, monomer or polymer coating treatment, coupling agent treatment, surface grafting, steam treatment, etc.) and physical treatments (ultraviolet irradiation treatment, plasma treatment, sputter etching treatment, surface roughening treatment). (2) Biocompatible adhesives In the present invention, a biocompatible adhesive refers to an adhesive of a grade that can be used for medical purposes without adversely affecting the human body. Biocompatible adhesives are used to bond parts of medical devices. Epoxy adhesives are biocompatible and have excellent strength and rigidity, so they are widely used in medical devices and can be suitably used in the embodiments of the present invention.

[0025] Figures 1(A) and (B) show oblique views of a spine cage according to one embodiment of the present invention, Figure 2(A) shows a state in which a titanium thin plate and a PEEK body of one embodiment of the spine cage of the present invention are joined via an adhesive, and Figure 2(B) shows a state in which hardened adhesive physically fits into a fine uneven structure formed on a titanium thin plate of one embodiment of the spine cage of the present invention.

[0026] Referring to Fig. 1(A), a spine cage 100 according to one embodiment of the present invention is approximately bullet-shaped, and the upper and lower surfaces are each formed with a concave and convex shape to prevent the cage inserted between the vertebrae from easily falling out. Referring to Fig. 1(B), the spine cage 100 of the present invention is composed of a PEEK body 10, a titanium thin plate 20 attached to the upper surface of the PEEK body, and a titanium thin plate 30 attached to the lower surface of the PEEK body.

[0027] Referring to FIG. 2(A), a titanium thin plate 20 is attached to the upper surface of a PEEK main body 10 by an adhesive. The adhesive is biocompatible and can be cured to obtain strong adhesion, and an epoxy adhesive can be preferably used. The upper surface of the PEEK main body 10 is surface-activated to enable the PEEK surface to be firmly bonded to the adhesive layer. The lower surface of the titanium thin plate 20 is roughened, and the adhesive penetrates into the recesses of the uneven structure of the roughened surface and hardens, so that the titanium thin plate 20 and the adhesive layer are physically fitted together (see FIG. 2(B)). The upper surface of the PEEK main body is made adhesive by chemical surface treatment such as plasma treatment, but it is also possible to perform a roughening treatment as a surface activation treatment, and in that case, the adhesive layer and the upper surface of the PEEK main body form a physical fit by the adhesive penetrating into the recesses of the uneven structure of the upper surface of the PEEK main body and hardening. Although Figures 2(A) and (B) show a case in which a titanium thin plate 20 is attached to the upper surface of a PEEK body 10 with an adhesive, the same applies when a titanium thin plate 30 is attached to the lower surface of a PEEK body 10 with an adhesive.

[0028] The titanium thin plate 20 is desirably thin enough to receive stress from the vertebrae, transmit the force to the PEEK body, and allow the PEEK body to deform. On the other hand, it is necessary that the titanium thin plate has a thickness that allows the titanium to be fused to the vertebrae after being subjected to a surface roughening treatment. The thickness of the titanium thin plate that satisfies these two conflicting requirements is preferably 0.5 to 5 mm, more preferably 1 to 3 mm.

[0029] FIG. 4 shows a flow chart of a method for manufacturing the spine cage of the present invention.

[0030] Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to these embodiments, and can be modified and implemented in various ways within the scope of the present invention.

[0031] 100 Spine Cage 10 PEEK body 20 Titanium thin plate (attached to the top surface of the PEEK body) 30 Titanium thin plate (attached to the underside of the PEEK body)

Claims

1. A spinal cage made of a PEEK and titanium composite for use in interbody fusion surgery, The spinal cage is configured by attaching titanium thin plates to the upper and lower surfaces of a roughly bullet-shaped PEEK body, The upper and lower surfaces of the PEEK body are modified by surface activation treatment, The surfaces of the two titanium thin plates attached to the upper and lower surfaces of the PEEK body, respectively, that come into contact with the PEEK body are roughened to form a fine uneven structure, The PEEK body and the two titanium thin plates are firmly joined to the upper and lower surfaces of the PEEK body via a layer of biocompatible adhesive applied between them, which adheres to the surface of the PEEK body that has been subjected to the surface activation treatment, and the biocompatible adhesive penetrates into the recesses of the fine uneven structure formed on the surface of the titanium thin plates and hardens to form a physical fit, thereby firmly joining the two titanium thin plates to the upper and lower surfaces of the PEEK body via the layer of biocompatible adhesive, When the spinal cage is inserted between the vertebral bodies of a patient and implanted, the two titanium thin plates attached to the PEEK body come into contact with the surrounding vertebrae, and are bonded to the vertebrae without being separated from the PEEK body while receiving stress from the vertebrae as the patient moves. A spinal cage made of a composite of PEEK and titanium for use in the interbody fusion surgery.

2. 2. The spine cage according to claim 1, wherein the titanium thin plate has a thickness of 0.5 to 5 mm.

3. The spinal cage according to claim 1 or 2, wherein the biocompatible adhesive is an epoxy adhesive.

4. The spinal cage according to claim 1 or 2, wherein the surface activation treatment includes ozone treatment, ultraviolet light irradiation treatment, various discharge treatments, or surface roughening treatment.

5. 1. A method for manufacturing a PEEK / titanium composite spinal cage for use in interbody fusion surgery, comprising: Prepare a roughly bullet-shaped PEEK body and two thin titanium plates to be attached to the top and bottom surfaces of the PEEK body. The upper and lower surfaces of the PEEK body are modified by surface activation treatment; The surfaces of the two titanium thin plates in contact with the PEEK body are roughened to form a fine uneven structure; The titanium thin plate is attached to the upper and lower surfaces of the PEEK body using a biocompatible adhesive, so that the layer of the biocompatible adhesive adheres to the upper and lower surfaces of the PEEK body that have been subjected to the surface activation treatment, and the biocompatible adhesive penetrates into the recesses of the fine uneven structure formed on the surface of the titanium thin plate and hardens, thereby forming a physical fit between the layer of the biocompatible adhesive and the surface of the titanium thin plate. A method for manufacturing a spinal cage made of a composite of PEEK and titanium for use in the interbody fusion surgery.

6. The method for manufacturing a spine cage according to claim 5, wherein the titanium thin plate has a thickness of 0.5 to 5 mm.

7. The method for manufacturing a spinal cage according to claim 5 or 6, wherein the biocompatible adhesive is an epoxy adhesive.

8. The method for manufacturing a spinal cage according to claim 5 or 6, wherein the surface activation treatment includes ozone treatment, ultraviolet irradiation treatment, and various discharge treatments.

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