Rod for fixing spine

Abstract

To provide a rod for a fixture in which a damage at the time of screw fixation is reduced, the rod having high rigidity and high durability against a deformation load and having significantly improved safety even at the time of breaking.SOLUTION: In a rod for a fixture 1, when a cross section thereof is viewed, a reinforcement fiber layer 2, a resin layer 3, and either a reinforcement fiber layer different from a fiber of the reinforcement fiber layer or a reinforcement fiber layer having a fiber skewed with respect to a fiber direction of the reinforcement fiber layer are alternately formed and each formed in plural layers.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rod for a fixation device used in a fixation device for fixing the spine. [Background technology]

[0002] 2. Description of the Related Art Metal rods for fixation devices are known as fixation devices for fixing the spine.

[0003] As an example of such a rod for a fixation device, for example, Patent Document 1 discloses a spinal pedicle rod having an internally reinforced polymer core at least partially enclosed in a polymer coating. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2011-508623 Summary of the Invention [Problem to be solved by the invention]

[0005] Although metal-based rods for fixation devices generally have excellent fixation power and strength, there is a problem that, during imaging by MRI or the like, the metal is magnetized in the magnetic field, which affects the magnetic field, causing image distortion and making it difficult to make a diagnosis using the captured image. On the other hand, the rod disclosed in Patent Document 1 does not have such a problem, but it is difficult to impart the desired rigidity due to the low fiber density, and it is known that it has problems with strength and durability, as well as a safety problem because the thorny fibers are exposed when broken.

[0006] One of the objects of the present invention is to provide a rod for a fastener which reduces breakage during screw fixation, has high rigidity and high durability against deformation load, and has significantly improved safety even in the event of breakage. Other objects of the present invention will become apparent by referring to the entire specification. [Means for solving the problem]

[0007] A rod for a fastener according to one embodiment of the present invention has, in cross section, a plurality of alternating layers of reinforcing fiber layers and either a resin layer, a reinforcing fiber layer whose fibers are different from those of the reinforcing fiber layer, or a reinforcing fiber layer whose fibers are oblique to the fiber direction of the reinforcing fiber layer.

[0008] In a rod for a fastener according to one embodiment of the present invention, the reinforcing fiber layer is a fiber reinforced resin, and carbon, glass, boron, SiC or aramid is used as the fiber, and epoxy, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK or PEEK is used as the resin.

[0009] In one embodiment of the present invention, the resin of the resin layer is epoxy, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK, or PEEK.

[0010] In a rod for a fastener according to one embodiment of the present invention, the reinforcing fiber layer different from the fibers of the reinforcing fiber layer is a fiber reinforced resin, and carbon, glass, boron, SiC or aramid is used as the fiber, and epoxy, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK or PEEK is used as the resin.

[0011] In the rod for a fastener according to one embodiment of the present invention, the reinforcing fiber layer or a reinforcing fiber layer different from the fibers of the reinforcing fiber layer has fibers aligned in one direction, formed in a woven fabric, or oriented randomly. Also, in the rod for a fastener according to one embodiment of the present invention, the fiber direction of the reinforcing fiber layer having fibers oblique to the fiber direction of the reinforcing fiber layer is oblique in the range of 10° to 90°.

[0012] In the rod for a fastener according to one embodiment of the present invention, when a plurality of layers are provided, either a resin layer, a reinforcing fiber layer having fibers different from those of the reinforcing fiber layer, or a reinforcing fiber layer having fibers oblique to the fiber direction of the reinforcing fiber layer, each layer is the same layer or a different layer.

[0013] In the rod for a fastener according to one embodiment of the present invention, the fibers of the reinforcing fiber layer are long fibers.

[0014] In the fastener rod according to one embodiment of the present invention, the reinforcing fiber layer has a fiber content of 60% by weight or more.

[0015] In a rod for a fastener according to one embodiment of the present invention, the fiber direction of the reinforcing fiber layer is aligned, and the thickness of the layer is in the range of 0.02 mm to 0.25 mm. Effect of the Invention

[0016] According to each of the above-described embodiments of the present invention, it is possible to provide a rod for a fastener which reduces breakage during screw fixation, has high rigidity and high durability against deformation load, and has significantly improved safety even in the event of breakage. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 shows a spinal fixation device 10 including a fixation rod according to one embodiment of the present invention. [Diagram 2] 1 is a schematic diagram showing a cross section of a rod for a fastener according to an embodiment of the present invention, cut along a plane perpendicular to its central axis. FIG. [Diagram 3] 1 is a schematic diagram showing a cross section of a rod for a fastener according to an embodiment of the present invention, cut along a plane perpendicular to its central axis. FIG. [Figure 4] 1 is a schematic diagram showing a cross section of a rod for a fastener according to an embodiment of the present invention, cut along a plane perpendicular to its central axis. FIG. [Diagram 5] 1 is a schematic diagram showing a cross section of a rod for a fastener according to an embodiment of the present invention, cut along a plane perpendicular to its central axis. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of a rod for a fastener according to the present invention will be described in detail with reference to the accompanying drawings. Elements common to multiple drawings are designated by the same reference numerals throughout the multiple drawings. Please note that the drawings are not necessarily drawn to scale for the sake of convenience.

[0019] 1 is a diagram showing a spinal fixation device 10 including a fixation device rod 1 according to an embodiment of the present invention. As shown in the figure, the spinal fixation device 10 includes a plurality of screw members 18 (two screw members 18 in the illustrated example) fixed to the bones of the spine, a plurality of rod fixing members 20 (two rod fixing members 20 in the illustrated example) attached to the screw members 18 and provided with a recess 21 for receiving the fixation device rod and a pressing member 22, and the fixation device rod 1 inserted into the recess 21 of the plurality of rod fixing members 20 and fixed by the pressing member 22.

[0020] Next, referring to Figs. 2, 3, and 4, a rod for a fixation device 1 according to one embodiment of the present invention used for a spinal fixation device 10 will be described. Figs. 2, 3, and 4 are views of the rod for a fixation device 1 shown in Fig. 1 taken along the line XX in the same figures. In the rod for a fixation device 1 according to one embodiment of the present invention, a reinforcing fiber layer 2 and any of the layers of a resin layer 3 (example shown in Fig. 2), a reinforcing fiber layer 4 (example shown in Fig. 3) different from the fiber of the reinforcing fiber layer, or a reinforcing fiber layer 5 (example shown in Fig. 4) having fibers oblique to the fiber direction of the reinforcing fiber layer are alternately formed in a plurality of layers. Here, the reinforcing fiber layer 2 and any of the layers of the resin layer 3 (example shown in Fig. 2), a reinforcing fiber layer 4 (example shown in Fig. 3) different from the fiber of the reinforcing fiber layer, or a reinforcing fiber layer 5 (example shown in Fig. 4) having fibers oblique to the fiber direction of the reinforcing fiber layer are formed to have a thickness of 0.01 mm to 0.25 mm, but the thickness of the layer may be different depending on the location of the layer (i.e., the layer may be formed so that there are thin parts and thick parts). Furthermore, the layer may be formed discontinuously (i.e., the layer may have thin and thick parts, or may have intervening parts where the layer thickness is zero).

[0021] According to the rod 1 for a fastener according to one embodiment of the present invention, it is possible to provide a rod for a fastener which reduces breakage during screw fixing, has high rigidity and high durability against deformation load, and is significantly safer even when broken. In particular, it has been found that when the rod 1 for a fastener according to one embodiment of the present invention breaks, stress is concentrated in any one of the resin layer sandwiched between the reinforcing fiber layers, the reinforcing fiber layer different from the fiber of the reinforcing fiber layer, or the reinforcing fiber layer having fibers oblique to the fiber direction of the reinforcing fiber layer, thereby reducing the reinforcing fiber layer from becoming thorny when the rod breaks, and as a result, it is possible to significantly improve safety to the human body.

[0022] In the rod 1 for a fastener according to one embodiment of the present invention, the reinforcing fiber layer 2 is a fiber-reinforced resin, and the fibers are made of carbon, glass, boron, SiC, or aramid, and the resin is made of epoxy, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK, or PEEK. In this way, it is possible to increase the bending rigidity and strength of the rod 1 for a fastener.

[0023] In the rod 1 for fastener according to one embodiment of the present invention, the resin of the resin layer 3 is epoxy, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK or PEEK.

[0024] In the rod for fastener according to one embodiment of the present invention, the reinforcing fiber layer 4 different from the fiber of the reinforcing fiber layer 2 is a fiber-reinforced resin, and the fiber is carbon, glass, boron, SiC or aramid, and the resin is epoxy, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK or PEEK. In this way, it is possible to increase the bending rigidity and increase the strength of the rod for fastener. The reason for using a reinforcing fiber layer different from the fiber of the reinforcing fiber layer is that by using different materials, different properties such as flexibility and vibration absorption other than rigidity and strength can be imparted.

[0025] In the rod for fastener according to one embodiment of the present invention, the reinforcing fiber layer or a reinforcing fiber layer different from the fibers of the reinforcing fiber layer may have fibers aligned in one direction, formed in a woven fabric, or oriented randomly. In the rod for fastener 1 according to one embodiment of the present invention, the fiber direction of the reinforcing fiber layer 5 having fibers oblique to the fiber direction of the reinforcing fiber layer 2 may be oblique in the range of 10° to 90°. In this way, by arranging an appropriate layered structure, it is possible to achieve the target strength and rigidity.

[0026] In the rod 1 for fastener according to one embodiment of the present invention, when any of the resin layer 3, the reinforcing fiber layer 4 having fibers different from those of the reinforcing fiber layer, or the reinforcing fiber layer 5 having fibers oblique to the fiber direction of the reinforcing fiber layer is provided in a plurality of layers, each layer is the same layer or a different layer (same below). For example, when two layers are provided, the resin layer 3 may be two layers (in this case, each layer is the same), or two different layers such as the resin layer 3 and the reinforcing fiber layer 4 having fibers different from those of the reinforcing fiber layer may be provided. When three or more layers are provided, a desired combination may be selected from the above layers. In this way, the target strength and rigidity can be achieved by arranging an appropriate stacking configuration.

[0027] In the fastener rod 1 according to one embodiment of the present invention, the fibers of the reinforcing fiber layer 3 are long fibers. In this way, the fibers of the reinforcing fiber layer 3 are long fibers, which makes it possible to further increase the bending rigidity and increase the strength.

[0028] In addition, in the rod for fastener 1 according to one embodiment of the present invention, the fiber content of the reinforcing fiber layer 3 is set to be 60% by weight or more. In this way, the fiber layer in which long fibers are concentrated at a high density makes it possible to form a rod for fastener 1 having high rigidity and excellent durability.

[0029] In the rod for fastener 1 according to one embodiment of the present invention, the fiber direction of the reinforcing fiber layer is aligned, and the thickness of the layer is, for example, in the range of 0.02 mm to 0.25 mm. In this way, the density of the resin is made uniform, and it is possible to reduce the variation in strength depending on the part.

[0030] Next, a method for manufacturing the rod for fastener 1 according to one embodiment of the present invention will be described. First, in step 1, any of the reinforcing fiber layer 2, the resin layer 3, the reinforcing fiber layer 4 having fibers different from those of the reinforcing fiber layer, or the reinforcing fiber layer 5 having fibers oblique to the fiber direction of the reinforcing fiber layer is cut to a predetermined size (layer cutting step). Then, in step 2, each layer is laminated in a predetermined arrangement (layer lamination step). In step 3, the layers are set in a predetermined mold and molded under predetermined conditions (for example, a temperature of 140°C and a pressure of 0.1 to 0.5 MPa) (molding step). Next, in step 4, the rod for fastener 1 according to one embodiment of the present invention is processed to a final shape and size (processing step). In this manner, the rod for fastener 1 according to one embodiment of the present invention is formed.

[0031] According to the rod for fastener 1 according to one embodiment of the present invention formed in this manner, it is possible to provide a rod for fastener which reduces breakage during screw fixing, has high rigidity and high durability against deformation load, and has significantly improved safety even when broken. In particular, it has been found that when the rod for fastener 1 according to one embodiment of the present invention breaks, by concentrating stress on any one of the resin layer sandwiched between the reinforcing fiber layers, the reinforcing fiber layer different from the fiber of the reinforcing fiber layer, or the reinforcing fiber layer having fibers oblique to the fiber direction of the reinforcing fiber layer, it is possible to reduce the reinforcing fiber layer from becoming thorny when the rod breaks, and as a result, it is possible to significantly improve safety to the human body.

[0032] Finally, referring to FIG. 5, a description will be given of a rod for a fixation device 1 according to another embodiment of the present invention used for a spinal fixation device 10. FIG. 5 shows the rod for a fixation device 1 shown in FIG. 1 as viewed in the XX cross section shown in the same figure. In the rod for a fixation device 1 according to one embodiment of the present invention, a reinforced fiber layer 2 and a resin layer 3, a reinforced fiber layer 4 having fibers different from those of the reinforced fiber layer, or a reinforced fiber layer 5 having fibers oblique to the fiber direction of the reinforced fiber layer are alternately formed in multiple layers in cross section, and a covering layer 6 is further formed on the outer surface of the rod for a fixation device 1. The covering layer 6 may be, for example, the same resin as that of the layer used in the rod for a fixation device 1 described above, but is not limited thereto. In this way, it is possible to further reduce the reinforcing fiber layer from becoming thorny when the rod is broken, and as a result, it is possible to further increase safety to the human body.

[0033] The dimensions, materials, and arrangement of each component described in this specification are not limited to those explicitly described in the embodiments, and each component can be modified to have any dimensions, materials, and arrangement that can be included in the scope of the present invention. In addition, components not explicitly described in this specification can be added to the described embodiments, and some of the components described in each embodiment can be omitted. [Explanation of symbols]

[0034] 1 Fixture rod 2 Reinforced fiber layer 3 Resin layer 4 Reinforced fiber layer different from the fiber of the reinforcing fiber layer 5. Reinforced fiber layer having fibers oblique to the fiber direction of the reinforcing fiber layer 6 Covering layer 10 Spinal fixation device 18 Screw member 20 Rod fixing member 21 Recess 22 Pressing member

Claims

1. A fastener rod, comprising:

1. A rod for a fastener, characterized in that, in cross section, reinforcing fiber layers and any one of a resin layer, a reinforcing fiber layer having fibers different from those of the reinforcing fiber layer, and a reinforcing fiber layer having fibers oblique to the fiber direction of the reinforcing fiber layer are alternately formed in a plurality of layers.

2. 2. The rod for fastener according to claim 1, wherein the reinforcing fiber layer is a fiber reinforced resin, and the fiber is carbon, glass, boron, SiC or aramid, and the resin is epoxy, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK or PEEK.

3. 3. The rod for fastener according to claim 1 or 2, wherein the resin of the resin layer is epoxy, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK or PEEK.

4. 4. The rod for fasteners according to claim 1, wherein the reinforcing fiber layer different from the fiber of the reinforcing fiber layer is a fiber-reinforced resin, and the fiber is carbon, glass, boron, SiC or aramid, and the resin is epoxy, phenol, unsaturated polyester, PA, PC, PPSU, POM, PP, PE, ABS, PS, PAEK or PEEK.

5. The rod for fasteners according to any one of claims 1 to 4, wherein the reinforcing fiber layer or a reinforcing fiber layer different from the fibers of the reinforcing fiber layer has fibers aligned in one direction, formed in a woven fabric, or randomly oriented.

6. 5. The rod for a fastener according to claim 1, wherein the fiber direction of the reinforcing fiber layer having fibers oblique to the fiber direction of the reinforcing fiber layer is oblique in a range of 10° to 90°.

7. 7. The rod for a fastener according to claim 1, wherein when a plurality of layers of any of the resin layer, the reinforcing fiber layer having fibers different from those of the reinforcing fiber layer, and the reinforcing fiber layer having fibers oblique to the fiber direction of the reinforcing fiber layer are provided, each layer is the same layer or a different layer.

8. 8. A rod for a fastener according to claim 1, wherein the fibers of the reinforcing fiber layer are long fibers.

9. 9. The rod for a fastener according to claim 1, wherein the fiber content of the reinforcing fiber layer is 60% by weight or more.

10. 10. The rod for a fastener according to claim 1, wherein the fiber direction of the reinforcing fiber layer is aligned, and the thickness of the layer is in the range of 0.02 mm to 0.25 mm.

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