Rod for spinal fixator and spinal fixator having the same

Abstract

Provided is a rod for a fixator that has excellent adhesion strength between a core material and a reinforcing fiber layer, is high in rigidity, and is also high in durability against deformation load. A rod for a fixator according to one embodiment is configured to include: a core member including a resin; and a reinforcing fiber layer provided on the core member, the resin of the core member and the resin of the reinforcing fiber layer being the same resin, or the resin of the core member and the resin of the reinforcing fiber layer being different resins and the critical surface tension of the resin of the core member and the resin of the reinforcing fiber layer each being 20 mN / m or greater.

Description

Technical Field

[0001] The present invention relates to a fixation rod used in a fixation device for fixing the spine, and a spinal fixation device having the fixation rod. Background Technology

[0002] Previously, it was known that metal was used as the rod in a fixation device for fixing the spine.

[0003] Furthermore, as a type of fixation rod, Patent Document 1 discloses, for example, a spinal pedicle rod having an internally reinforced polymer core that is at least partially inserted into a polymer coating. Prior Art Documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Publication No. 2011-508623 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Metal-based fixation rods typically offer excellent fixing force and strength. However, during imaging such as MRI, the magnetic field is affected by the magnetization of the metal, causing image distortion and hindering diagnostics based on the captured images. On the other hand, while the rod disclosed in Patent Document 1 does not have this problem, even when using adhesives to bond the polymer core material to its coating layer, it is difficult to achieve uniform and reliable bonding, resulting in a lack of stable bond strength.

[0008] One object of the present invention is to provide an immobilizer rod with excellent bonding strength between the core material and the reinforcing fiber layer, high rigidity, and high durability based on deformation load, and a spinal immobilizer having the immobilizer rod. Other objects of the present invention become apparent from reference to this specification in its entirety.

[0009] Methods for solving problems

[0010] One embodiment of the present invention provides a retainer rod comprising: a core component comprising resin; and a reinforcing fiber layer disposed on the core component, wherein the resin of the core component and the resin of the reinforcing fiber layer are the same resin, or the resin of the core component and the resin of the reinforcing fiber layer are different resins and the critical surface tensions of the resin of the core component and the resin of the reinforcing fiber layer are both 20 mN / m or more.

[0011] In a retainer rod according to one embodiment of the present invention, one or more recesses are formed on the outer surface of the core component.

[0012] In a retainer rod according to one embodiment of the present invention, the recess is formed along the circumference of the core component.

[0013] In a retainer rod according to one embodiment of the present invention, the recess is formed along the axial length direction of the core component.

[0014] In a retainer rod according to one embodiment of the present invention, the recess is formed in a direction inclined relative to the circumferential direction of the core component.

[0015] In a fixing rod according to one embodiment of the present invention, the recess includes two or more recesses formed in different directions.

[0016] In a retainer rod according to one embodiment of the present invention, the depth of the recess is in the range of 3 μm to 200 μm.

[0017] In a retainer rod according to one embodiment of the present invention, the core component is formed of a resin containing fibers.

[0018] In a retainer rod according to one embodiment of the present invention, a portion of the fibers of the core component is exposed from the core component.

[0019] In one embodiment of the fastener rod of the present invention, the fibers of the core component are long fibers. Alternatively, in another embodiment of the fastener rod of the present invention, the fibers of the core component are short fibers.

[0020] In a retainer rod according to one embodiment of the present invention, the resin of the core component is composed of any material selected from epoxy resin, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK, or PEEK.

[0021] One embodiment of the spinal fixation device of the present invention has a fixation rod of any of the above-mentioned types.

[0022] Invention Effects

[0023] According to the above embodiments of the present invention, it is possible to provide a fixation rod with excellent bonding strength between the core material and the reinforcing fiber layer, high rigidity, and high durability based on deformation load, as well as a spinal fixation device having the fixation rod. Attached Figure Description

[0024] Figure 1 This is a diagram showing a spinal fixator 10 with a fixation rod according to one embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram showing a cross-section of a retainer rod according to one embodiment of the present invention cut with a plane perpendicular to its central axis.

[0026] Figure 3 This is a diagram illustrating the core component of a fixing rod according to one embodiment of the present invention.

[0027] Figure 4 This is a diagram illustrating the core component of a fixing rod according to one embodiment of the present invention.

[0028] Figure 5 This is a diagram illustrating the core component of a fixing rod according to one embodiment of the present invention.

[0029] Figure 6 This is a diagram illustrating the core component of a fixing rod according to one embodiment of the present invention.

[0030] Figure 7 This is a diagram illustrating the core component of a fixing rod according to one embodiment of the present invention.

[0031] Figure 8 This is a diagram illustrating the core component of a fixing rod according to one embodiment of the present invention.

[0032] Figure 9 This is a diagram illustrating a method for forming a fixing rod according to one embodiment of the present invention. Detailed Implementation

[0033] Hereinafter, embodiments of the fixing rod of the present invention will be specifically described with reference to the accompanying drawings. Common structural elements are labeled with the same reference numerals in the various drawings. It should be noted that, for ease of explanation, the drawings are not necessarily shown at an exact scale. Figure 1 This is a diagram illustrating a spinal fixator 10 incorporating a fixator rod 1 according to one embodiment of the present invention. As shown, the spinal fixator 10 includes: a plurality of screw components 18 (two screw components 18 in the illustrated example) fixed to the vertebrae; a plurality of rod fixing components 20 (two rod fixing components 20 in the illustrated example) mounted on the screw components 18, having a recess 21 for receiving the fixator rod and a pressing member 22; and a fixator rod 1 inserted into the recess 21 of the plurality of rod fixing components 20 and fixed by the pressing member 22.

[0034] Next, refer to Figure 2 The following describes a fixation rod 1 of one embodiment of the present invention used in a spinal fixation device 10. Figure 2 Yes, yes Figure 1 The image shows the rod 1 of the fixing device as observed at the XX section shown in the figure.

[0035] As shown in the figure, in one embodiment of the present invention, the fixing rod 1 is configured to include a core component 2 containing resin and a reinforcing fiber layer 3 disposed on the core component 2. The resin of the core component 2 and the resin of the reinforcing fiber layer 3 are the same resin, or the resin of the core component and the resin of the reinforcing fiber layer are different resins and the critical surface tensions of the resin of the core component and the resin of the reinforcing fiber layer are 20 mN / m or more, respectively.

[0036] According to one embodiment of the present invention, a fastener rod 1 provides a fastener rod with excellent bonding strength between the core material and the reinforcing fiber layer, high rigidity, and high durability based on deformation load. More specifically, by using the same resin, or even different resins but with critical surface tensions of 20 mN / m or more for both the core component resin and the reinforcing fiber layer resin, the affinity between the core material and the reinforcing fiber layer is improved, resulting in excellent bonding strength between them. Furthermore, by employing a solid double structure, and as described later, using a material with a high average flexural modulus of elasticity in the outer layer, a fastener rod with excellent overall flexural rigidity and crush strength can be provided. Here, the average flexural modulus of elasticity is a value calculated by dividing the overall flexural rigidity of the portion by the second moment of force applied to that portion.

[0037] Here, even if the resin of the core component and the resin of the reinforcing fiber layer are different resins, if the critical surface tensions of the resin of the core component and the resin of the reinforcing fiber layer are both above 20 mN / m, it is confirmed that the critical surface tension of the resin exceeds the expected adhesive performance in bonding dissimilar materials, and it is determined that special processes such as chemical treatment or plasma treatment for bonding are not required. More specifically, for example, the critical surface tensions of PP (polypropylene), PE (polyethylene), PS (polystyrene), POM (polyoxymethylene), PET (polyethylene terephthalate), and Nylon 66 are 22-29 mN / m, 31 mN / m, 33 mN / m, 36-38 mN / m, 43 mN / m, and 46 mN / m, respectively. It can be seen that even if the resin of the core component and the resin of the reinforcing fiber layer are different resins, good adhesive performance is exhibited due to the critical surface tension of the resin. On the other hand, PTFE (polytetrafluoroethylene paraffin) has a critical surface tension of 18.5 mN / m. Since the critical surface tension of the resin is lower than the desired bonding performance in bonding dissimilar materials, special processes such as chemical treatment or plasma treatment are required for bonding. However, this is not a limitation if the resin in the core component and the resin in the reinforcing fiber layer are the same resin.

[0038] In the retainer rod 1 of one embodiment of the present invention, the resin of the core component 2 is a thermosetting resin (e.g., epoxy resin, phenol, unsaturated polyester, etc.) or a thermoplastic resin (e.g., PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK, or PEEK, etc.).

[0039] In one embodiment of the fastener rod 1 of the present invention, the core component 2 can be formed from a resin containing fibers. In this case, the fibers are any of carbon, glass, aramid, boron, or SiC, and the resin is configured as a thermosetting resin (e.g., epoxy resin, phenol, unsaturated polyester, etc.) or a thermoplastic resin (e.g., PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK, or PEEK, etc.). This allows for increased bending stiffness and higher strength of the core component.

[0040] In a fastener rod 1 according to one embodiment of the present invention, the reinforcing fiber layer 3 is a fiber-reinforced resin. The fiber used is carbon, glass, boron, SiC, or aromatic polyamide, and the resin used is a thermosetting resin (e.g., epoxy resin, phenol, unsaturated polyester, etc.) or a thermoplastic resin (e.g., PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK, or PEEK, etc.). This increases the bending stiffness and strength of the reinforcing fiber layer. The fastener rod 1 according to one embodiment of the present invention is configured to include a cover layer disposed on the reinforcing fiber layer 3. This cover layer can be formed, for example, from epoxy resin, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK, or PEEK, but is not limited thereto.

[0041] Next, refer to Figures 3-8 The core component 2 of the fixation rod 1 of one embodiment of the present invention for use in a spinal fixation device 10 will be described. In the fixation rod 1 of one embodiment of the present invention, one or more recesses are formed on the outer surface of the core component 2. In this way, during molding, the contact surface area between the core component 2 and the reinforcing fiber layer 3 is increased, thereby significantly improving the bonding strength between the core material and the reinforcing fiber layer. This will be described in more detail below.

[0042] like Figure 3As shown, in a fastener rod 1 according to one embodiment of the present invention, the recess (circumferential recess) 11 is formed in the circumferential direction of the core member 2. In the illustrated example, seven recesses 11 are formed, but the desired number can be set and is not limited to a specific number. Furthermore, the recesses can be formed in all or part of the circumferential direction of the core member 2. Alternatively, the recesses 11 can be formed intermittently in all or part of the circumferential direction of the core member 2. Thus, by providing recesses in the circumferential direction of the core member, the bonding area is increased, and axial displacement between the core member 2 and the reinforcing fiber layer 3 can be suppressed.

[0043] Next, as Figure 4 As shown, in a fastener rod 1 according to one embodiment of the present invention, the recess (axial recess) 12 is formed along the axial length direction of the core member 2. In the illustrated example, eight recesses 12 are formed, but the desired number can be set and is not limited to a specific number. Furthermore, the recesses can be formed along all or part of the axial direction of the core member 2. Alternatively, the recesses 12 can be formed intermittently along all or part of the axial direction of the core member 2. Thus, by providing recesses along the axial direction of the core member, the bonding area is increased, and the offset of the rotational direction between the core member 2 and the reinforcing fiber layer 3 can be suppressed.

[0044] Next, as Figure 5 As shown, in the retainer rod 1 of one embodiment of the present invention, the recess (inclined direction recess) 13 is formed to be circumferentially inclined relative to the core member 2. In the illustrated example, seven recesses 13 are formed, but the desired number can be set, and it is not limited to a specific number. In addition, it can be formed on the entire circumference or a part thereof of the core member 2. Alternatively, the recesses 13 can be formed intermittently on the entire circumference or a part thereof of the core member 2. In this way, by setting the recesses in a direction inclined relative to the circumferential direction of the core member, the bonding area is increased, and the axial and rotational offset between the core member 2 and the reinforcing fiber layer 3 can be suppressed.

[0045] Next, as Figure 6 As shown, in a retainer rod 1 according to one embodiment of the present invention, the recesses (recesses in different directions) 14 are formed on the surface of the core member 2 in such a manner that they include two or more recesses formed in different directions respectively. In the illustrated example, a plurality of recesses 14 are formed, but the desired number can be set and is not limited to a specific number. In addition, when there are three or more recesses 14, two or more of the recesses 14 may also be formed in the same direction. In addition, they can be formed on the entire surface of the core member 2 or a part thereof. Alternatively, the recesses 11 may be formed intermittently on the entire surface of the core member 2 or a part thereof. In this way, by providing the recesses in different directions, it is possible to suppress offsets in multiple different directions.

[0046] In a retainer rod according to one embodiment of the present invention, the depth of the recess is in the range of 3 μm to 200 μm. This allows for setting a suitable range to suppress changes in rigidity and deviations caused by the recess, and to suppress misalignment between the core component 2 and the reinforcing fiber layer 3.

[0047] In a fastener rod 1 according to one embodiment of the present invention, the core component 2 can be formed from a resin containing fibers, but the fibers of the core component are short fibers. By using short fibers, the fiber orientation can be randomized, and reinforcement can be achieved in all directions.

[0048] In a fastener rod 1 according to one embodiment of the present invention, the core component 2 can be formed from a resin containing fibers, but the fibers of the core component are long fibers. In this way, bending stiffness can be effectively improved.

[0049] Next, in the retainer rod 1 of one embodiment of the present invention, as described above, the core component 2 can be formed from a resin containing fibers. In such a case, as... Figure 7 As shown, in the retainer rod 1 of one embodiment of the present invention, a portion of the fiber (short fiber) 15 of the core component 2 is exposed from the surface of the core component. In this way, by exposing the short fiber 15, minute irregularities can be created on the surface of the core component 2, suppressing the misalignment between the core component 2 and the reinforcing fiber layer 3.

[0050] Next, in the retainer rod 1 of one embodiment of the present invention, as described above, the core component 2 can be formed from a resin containing fibers. In such a case, as... Figure 8 As shown, in the retainer rod 1 of one embodiment of the present invention, a portion of the fiber (long fiber) 16 of the core component 2 is exposed from the surface of the core component 2. In this way, by exposing the long fiber 16, minute irregularities are created on the surface of the core component 2, which can suppress the misalignment between the core component 2 and the reinforcing fiber layer 3.

[0051] In the retainer rod 1 of one embodiment of the present invention, the reinforcing fiber layer 3 is composed of long fibers. By using long fibers in the reinforcing fiber layer 3, it is possible to further increase the bending rigidity and achieve high strength.

[0052] Furthermore, in one embodiment of the fastener rod 1 of the present invention, the fiber content of one or more layers comprising the reinforcing fiber layer 3 is 60% by weight or more. Thus, by using a fiber layer with long fibers and high density, a fastener rod 1 with high rigidity and excellent durability can be formed.

[0053] Next, refer to Figure 9The following describes a method for manufacturing a fastener rod 1 according to one embodiment of the present invention. First, as step 1, a core component (core material) (including the above-described...) is prepared. Figures 3-8 (various methods) Figure 9 (a)). Next, as step 2, fiber-reinforced resin material is prepared ( Figure 9 (b)). Next, as step 3, fiber-reinforced resin material is wound onto the core material to form an integral fiber-reinforced material component. Figure 9 (c)).

[0054] Next, in step 4, a strip is wound around the outer surface of the integral fiber-reinforced resin component as an outer mold. Figure 9 (d)). Next, in step 5, the integral component of fiber-reinforced resin material wound with the tape is fired (molded) ( Figure 9 (e)). Then, as in step 6, remove the fired fiber-reinforced resin integral component and cut off the unwanted parts. Figure 9 (f)). Finally, as step 7, by removing the strip of the integral fiber-reinforced resin material component from which the unwanted portion has been cut off, a retainer rod 1 (of the present invention having a core component and a fiber-reinforced resin layer) according to an embodiment of the present invention can be obtained. Figure 9 (g)

[0055] According to one embodiment of the present invention, the retainer rod 1 formed in this way provides a retainer rod with excellent bonding strength between the core material and the reinforcing fiber layer, high rigidity, and high durability based on deformation load. More specifically, by using the same resin, or even different resins but with critical surface tensions of 20 mN / m or more for both the core component resin and the reinforcing fiber layer resin, the affinity between the core material and the reinforcing fiber layer is improved, resulting in excellent bonding strength between them. Furthermore, by employing a solid double structure, and as described later, using a material with a high average flexural modulus of elasticity in the outer layer, a retainer rod with excellent overall flexural rigidity and crush strength can be provided. Here, the average flexural modulus of elasticity is the value calculated by dividing the overall flexural rigidity of the portion by the second moment of force applied to that portion.

[0056] A spinal fixation device 10 according to one embodiment of the present invention has any of the fixation rods 1 described above.

[0057] The dimensions, materials, and configurations of the structural elements described in this specification are not limited to those explicitly described in the embodiments. These structural elements can be modified to have any dimensions, materials, and configurations that fall within the scope of this invention. Furthermore, structural elements not explicitly described in this specification can be added to the described embodiments, and some structural elements described in each embodiment can be omitted.

[0058] Label Explanation

[0059] 1: Fixation rod; 2: Core component; 3: Reinforcing fiber layer; 10: Spinal fixation device; 11: Recess (circumferential recess); 12: Recess (axial recess); 13: Recess (inclined direction recess); 14: Recess (recess in different directions); 15: Fiber (short fiber); 16: Fiber (long fiber); 18: Screw component; 20: Rod fixing component; 21: Recess; 22: Pressing component.

Claims

1. A rod for a fastener, characterized in that, The retainer rod includes: Core component, comprising resin; and A reinforcing fiber layer is disposed on the core component. The resin of the core component is the same as the resin of the reinforcing fiber layer, or the resin of the core component and the resin of the reinforcing fiber layer are different resins and the critical surface tensions of the resin of the core component and the resin of the reinforcing fiber layer are both 20 mN / m or more. The outer surface of the core component has a plurality of recesses, which are respectively formed to extend along the circumferential direction or in a direction inclined relative to the circumferential direction, either in whole or in part, of the core component. The depth of the recess is in the range of 3μm to 200μm, which suppresses changes in rigidity and deviations caused by the recess and suppresses the offset between the core component and the reinforcing fiber layer.

2. The rod for fixing according to claim 1, wherein, The recess includes two or more recesses formed in different directions.

3. The rod for fixing according to claim 1 or 2, wherein, The core component is formed from a resin containing fibers.

4. The rod for fixing according to claim 3, wherein, A portion of the fibers of the core component is exposed from the core component.

5. The rod for fixing according to claim 3, wherein, The fibers of the core component are long fibers.

6. The rod for fixing according to claim 3, wherein, The fibers in the core component are short fibers.

7. The rod for fixing according to claim 1 or 2, wherein, The resin of the core component is any material selected from epoxy resin, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK, or PEEK.

8. A spinal fixation device having a fixation rod as described in any one of claims 1 to 7.

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