WO2008018412A1 - Bone fastening hollow cable - Google Patents

Abstract

A bone fastening cable capable of bone fastening with a width satisfactory for wiping out the fear of bone depression or severance, which bone fastening hollow cable is improved so as to be capable of preventing any torsion at the time of fastening and so as to be easily passed through the interstice between the vertebral arch and the spinal cord in spinal surgery. The cable is a bone fastening hollow cable formed into a tubular configuration of roughly circular cross section by fiber knitting, which can be crushed by fastening of a fastening object to thereby be deformed into a belt configuration.

Description

 Specification

 Hollow cable for bone fastening

 Technical field

 [0001] The present invention relates to a cable for fastening bones used in various bone operations, and more specifically, bone transplantation for fixing and fixing a plurality of adjacent vertebrae in damaged bones, particularly in spinal surgery. This is related to the cable used to fasten the vertebrae in the body directly or with a metal fixation device in order to acquire the immobility of the spinal column.

 Background art

[0002] For bone fixation (referring to uniting bones by fusion), for example, for fixing broken bone parts, and for fixing damaged bone and bone graft fragments in bone grafting These bones must be firmly attached to each other in the correct positional relationship, and must be held firmly to each other so that the bones do not shift until the fusion is completed. For this holding, bones are typically fastened with a metal wire (wire) such as stainless steel or titanium, and various metal rods, hooks, bolts (pedicles) are used depending on the situation. Screw or pedicle screw) and other instruments. However, due to its rigidity, the wire is inadvertently pressed against the spinal cord when it is passed under the vertebral arch (where the spinal cord passes), for example, during spinal surgery, causing serious damage. The surgeon needs to be very careful not to give it. Even after surgery, the wire may be severed if a large force is repeatedly applied to the bone, and there is a risk that the resulting stump may seriously damage the spinal cord. For this reason, in order to avoid these problems and to enable safer spinal procedures, recently, instead of wires, for example, synthetic fibers (such as ultra-high molecular weight polyethylene (also called “ultra-high-strength polyethylene”) are used. High-strength synthetic fibers) and cables made of metal fibers have become widely known. As a bone fastening cable made of synthetic fiber, a Nespron (registered trademark) cable system (non-woven) made of braided ultrahigh molecular weight polyethylene fiber and having a thin tape shape with a width of 3 mm or 5 mm Patent Document 1) is widely used in clinical practice. In addition, as a cable for bone fastening made of fiber, a cross section made of braided fiber is generally used. A solid cable having a substantially circular shape, that is, a non-directional cross section is known (see Patent Document 1).

 [0003] The spinal column is composed of vertebrae (consisting of vertebral bodies and vertebral vertebrae) connected in series via a cartilage disc (intervertebral disc). providing. In spinal surgery, a cable was wrapped around the vertebra underneath the vertebra to hold it, and the cable tension was maintained with the vertebra adjacent to it or with a metal fixation device placed adjacent to it. By tightening in a state, the technique of holding the vertebra in question in place is frequently performed. The spinal cord runs under the vertebral arch, and the cable is passed through the gap between the vertebral arch and the spinal cord. At this time, a solid cable with a circular cross-section can be made narrower than a tape-shaped cable, so it is easy to pass through the gap between the vertebral arch and spinal cord. Therefore, there is an advantage that it is easy to avoid the cable coming into contact with the spinal cord! However, on the other hand, solid cables with a circular cross section are prone to bone depressions and cuts when fastened. This is because a solid cable with a circular cross-section has a narrow width and force, but the entire surface is round (ie, not flat), so that the contact area between the bone and the cable is small, and pressure is concentrated on the contact area when fastened. This is because the bones can not withstand the burden and are cut. This is especially true when the affected bone is brittle due to rheumatoid arthritis or osteoporosis. If bone depressions or incisions occur during surgery, the surgical plan must be changed, and if it occurs after surgery, if the surgery is necessary, the fastening site is not the force, the glue, and the spine. In the case of a vertebra, there is a risk of causing spinal cord injury before reoperation.

[0004] On the other hand, the tape-shaped cable makes contact with the bone surface across the flat surface that is wider than the circular cross-section cable when the bone is fastened. Since the pressure drops per unit area when dispersed, it has the great advantage of being less prone to recesses and cuts. On the other hand, this type of cable is wider than a solid cable with a circular cross-section, so that when the cable is passed through the gap between the spinal cord and the vertebral arch, the edge tends to come into contact with the spinal cord. Requires appropriate skills. Furthermore, when a tape-shaped cable is wound around a bone, it is likely to be inadvertently twisted at the site behind the bone that is not visible to the operator (that is, the front and back are reversed halfway). There is a possibility that the fastening operation is completed without recognizing this and returning it. Twisted part is tape-shaped The cable was folded and overlapped in part, and the thickness doubled and the width locally decreased in the overlapped part. Therefore, if it is not noticed to be twisted and fastened without untwisting it, the bone surface in contact with the twisted part is undesirably subjected to pressure, and the stress distribution in the cable is disturbed at the twisted part. Adversely affects the strength of the cable.

 [0005] Thus, both types of cables have conflicting advantages and disadvantages. In spinal surgery, the use of cable fastening alone or in combination with metal fixation devices such as bolts and hooks is becoming more widespread and is used by more physicians. There is a potential need for a bone fastening cable that maintains the advantages of both types of cables while improving the shortcomings, making it easier to handle, safer and more secure to fit.

 [0006] Patent Document 1: Japanese Patent Laid-Open No. 7-163583

 Non-Patent Document 1: "Nespron Cable System" pamphlet, Alfresa Pharma Corporation, October 2004

 Disclosure of the invention

 Problems to be solved by the invention

[0007] In the above background, the present invention is a bone fastening cable capable of fastening a bone with a sufficient width to eliminate the fear of bone depression or cutting. It is an object of the present invention to provide an improved cable for bone fastening, which can be prevented, and has the advantage of being easily passed through the gap between the vertebral arch and spinal cord in spinal surgery.

 Means for solving the problem

 [0008] As a result of repeated investigations in line with the above-mentioned purpose, the present inventor has obtained a cylindrical shape, which is produced by braiding fibers and has a substantially circular cross section and a lumen having a sufficient inner diameter compared to the outer diameter. This hollow cape is easy to pass through the gap between the vertebral arch and spinal cord, so it has the same advantages as a conventional cable, and twisting occurs, and it is pressed against the bone surface during fastening and collapses. Since it has a tape shape, it has been found that the advantages of the conventional tape that it is less likely to cause dents and cuts in the bone are obtained, and based on this, the present invention has been completed.

That is, the present invention provides the following. 1. A hollow cable for fastening bones, which can be crushed and deformed into a belt by fastening the fastening object, and is formed by braiding fibers into a tubular shape with a roughly circular cross section.

 2. The bone fastening hollow cable of 1 above, wherein the ratio of the outer diameter to the inner diameter is 1.;! ~ 2.0.

Yes

 3. The hollow cable for fastening bone according to 1 or 2 above, which has an inner diameter of 1.0 to 10. Omm.

 4. The hollow cable for fastening bone according to any one of 1 to 3 above, wherein the fiber is an organic fiber and / or an inorganic fiber.

 5. The organic fiber is one or more fibers selected from the group consisting of polyolefin, polyamide, polyacrylonitrile and silk, and the inorganic fibers are selected from the group consisting of titanium, titanium alloy and stainless steel. The bone fastening hollow cable according to 4 above, wherein the hollow cable is one or more fibers.

 6. The bone fastening hollow cable according to any one of 1 to 5 above, which is formed by plain weaving or oblique weaving of fibers.

 The invention's effect

 [0010] Since the present invention configured as described above is in the form of a cylindrical cable before the bone is fastened, the operation of passing through the gap between the vertebral arch and the spinal cord is easy. In addition, since it has a circular cross-section, it is extremely unlikely to be twisted in the middle like a tape-shaped cable, so that it can be prevented from being tightened without noticing the fact that it is twisted behind the bone. In addition, it is strongly pressed against the bone surface by the tensile force applied to the cable during fastening, and it collapses and deforms into a flat tape shape. Therefore, unlike a solid cable with a circular cross-section, the contact surface with the bone is wide, and the bone As a result of the dispersal of the tightening force, it has the advantage that it is less prone to bone depressions and cuts than conventional cables with a circular cross section. Thus, according to the present invention, the advantages of the conventional circular cross-section cable for bone fixation and the advantages of the tape-shaped cable are combined, and the bone depression and The ability to eliminate both the ease of incision and the difficulty of passing through the gap between the vertebral arch and spinal cord, which was a drawback of conventional tape-shaped cables, can be solved.

 Brief Description of Drawings

[0011] FIG. 1 is a schematic diagram of fastening by a double loop. [Fig. 2] Fig. 2 is a schematic diagram of plain weave.

 [Fig. 3] Fig. 3 is a schematic diagram of twill weave.

 [Fig. 4] Fig. 4 is an enlarged photograph of the vicinity of the stump of the hollow cable of Example lb.

 BEST MODE FOR CARRYING OUT THE INVENTION

[0012] The cable of the present invention is a hollow cable having a substantially circular cross section, and the cross-sectional state is maintained until it is wrapped around a hard fastening object such as a bone and tightened, that is, until used for fastening the fastening object. It is produced so as to have a hardness as high as possible. This can be easily achieved simply by using, for example, a resin-made long wire or tube with a circular cross section as the core material and braiding the fibers closely around it. In other words, the hollow cable produced in this way is still strongly pressed against the bone surface when it is wound around the bone, for example, inside the vertebral arch and passed through the gap with the spinal cord after the core material is removed. As a result, a substantially circular cross-sectional shape can be maintained. Even if it has such hardness, when the cable is tightened by squeezing both ends of the cable after it is wrapped around the bone, the side of the cable is strongly pressed against the bone surface. It deforms into a shape and comes into contact with the bone on its flat surface. The braiding method is not particularly limited, and for example, plain weaving (Fig. 2), oblique weaving (Twill weaving) (Fig. 3), etc. may be used as appropriate.

 [0013] As the fibers constituting the cable of the present invention, it is possible to use both organic fibers and inorganic fibers. Organic fibers are preferable to metal fibers because of their excellent flexibility.

 [0014] Examples of organic fibers include polyolefins such as polyethylene and polypropylene, polyethylene terephthalate, polylactic acid, polydarlicolic acid, polydaricholic acid 'lactic acid, polyesters such as polydioxanone, polyamides such as nylon 6, nylon 66, and other polyacrylonitriles. Natural fibers such as synthetic fibers and silk can be used. When biodegradable fibers such as polylactic acid, polydaricholic acid, polydalicholic acid 'lactic acid, polydioxanone, etc. are not long enough to fasten bones, it is preferable that they are decomposed, absorbed and disappear after that. Can be used. In addition, these fibers are highly compatible with living organisms, so that they can be used in addition to other fibers (for example, by twisting) to increase the biocompatibility of cables mainly composed of other fibers. It can also be used.

[0015] These various organic fibers may be used alone or in combination of two or more. For example, high-strength fibers for obtaining high strength and fastening strength are mainly used, and other fibers may be braided together. In addition, since organic fibers are X-ray transparent, X-ray diagnosis cannot be performed on the condition of the cable after bone fastening, but X-ray opaque material (for example, a barium compound) is mixed with the raw resin. A spun fiber can also be used in the present invention. A cable made using such X-ray-impermeable fibers in at least one part can be captured as an X-ray image. If this is used for bone fastening, the cable tightened state in the patient after bone fastening This is useful in that it is easy to test. In particular, as a high-strength fiber, an ultra-high molecular weight polyethylene fiber (molecular weight of 400,000 or more), which is a kind of polyethylene fiber, is particularly suitable as a fiber used in the present invention because of its high tensile strength and tensile modulus. Yes.

 [0016] As the inorganic fibers, materials conventionally used as bone fastening cables, such as titanium, titanium alloys and alloys thereof, and stainless steel, can be used.

 [0017] If desired, a cable can also be produced using a combination of organic fibers and inorganic fibers. For example, a hollow cable made by incorporating a part of inorganic fiber into an X-ray permeable organic fiber can be captured in the X-ray image, enabling X-ray inspection of the cable in the patient.

 [0018] The hollow cable for bone fastening of the present invention has an inner diameter (that is, a diameter of the lumen) that is sufficiently large compared to the outer diameter so as to become a flat tape shape when the fastening object is crushed by fastening. ) Is preferable. For this purpose, the ratio of the outer diameter to the inner diameter is preferably 1.;! ~ 2.0, and more preferably 1.;! ~ 1.5.

 [0019] The preferred inner diameter of the bone fastening hollow cable of the present invention varies depending on the part to be fastened and the fastening force required, but is usually preferably 1.0 to 10 mm, more preferably 1. 5 ~ lOmm "C¾.

 [0020] The bone fastening hollow cable of the present invention can be used particularly advantageously in conventional spinal surgery compared to conventional cables, but is also handled when fastening bones in other parts of the body. It can be used for an IJ because it is easy to prevent, prevents bone depressions and cuts, and avoids twisting.

[0021] The bone fastening hollow cable of the present invention is supplied while including the core material at the time of manufacture, and the operating room. The core material may be pulled out at the same time, and when it is supplied in a box or the like so that it is not subject to inadvertent pressure during transportation and storage, it may be supplied with only the hollow cable with the core material pulled out. Good.

 Example

 Hereinafter, the present invention will be described more specifically with reference to typical examples. However, it is not intended that the present invention be limited to these examples.

[0023] [Example 1]

 Hollow fibers were made by plain weaving with 24 spindles using two layers of 100 denier yarn made of ultra high molecular weight polyethylene fibers (denier: mass per 9000m (g)). A polytetrafluoroethylene resin tube with an outer diameter of 2 mm is used as the core material, and the gear ratio between the winding side gear and the spindle side gear is set around it using a No. 101 (medium) round string machine manufactured by KOKUBUN LIMITED. By changing (100/45, 100/40, or 100/32), three types of hollow cables with different braid densities were produced (Example la, lb, and 1c, respectively). All of the fabricated hollow cables maintained a circular cross-section until they were pressed by fastening the object to be fastened, even if the core material was pulled out. The inner diameter of these hollow cables was 2 mm. Table 1 shows the number of yarns wound per unit length of these hollow cables and the outer diameter of the cables. Figure 4 shows a photograph of the cut end of the hollow cable of Example lb.

 [0024] Example Each of the la and lc hollow cables, a loop formed by doubling as shown schematically in Fig. 1 is formed and wound around two round pipes of a tensile tester. The maximum traction force (hereinafter referred to as “maximum fixing strength”) was also measured by pulling the directional force and maintaining the loop fixed. The results are shown in Table 2.

 [0025] In addition, as shown schematically in Fig. 1, each of the lb and lc hollow cables in Example 1 was formed by wrapping and fastening two round pipes in a double loop. Thus, the width and thickness of the cable part in contact with the round pipe (referred to as “width at fastening” and “thickness at fastening”, respectively) were measured. The results are shown in Table 3.

 [Example 2]

250 denier made of ultra high molecular weight polyethylene fiber instead of the yarn used in Example 1 Three types of hollow cables were produced in the same manner as in Example 1 using a single thread without overlapping them (Examples 2a, 2b, and 2c, respectively). The fabricated hollow cable maintained a circular cross-section until it was compressed by fastening the object to be fastened, even if the core material was pulled out. The inner diameter of these hollow cables was 2 mm. Table 1 shows the outer diameter of these hollow cables and the number of yarn windings per unit length.

 [0027] The maximum fixing strength was measured in the same manner as in Example 1 for each of the hollow cables of Examples 2a and 2c. The results are shown in Table 2. For Examples 2b and 2c, the width at fastening and the thickness at fastening were measured in the same manner as in Example 1. The results are shown in Table 3.

 [Example 3]

 Two hollow cables were produced in the same manner as in Example 1 (with gear ratios of 100/45 and 100/40) using two 250 denier yarns used in Example 2 in a stack. (Examples 3a and 3b, respectively). The fabricated hollow cable maintained a circular cross-section until it was compressed by fastening the object to be fastened, even if the core material was pulled out. The inner diameter of these hollow cables was 2 mm. Table 1 shows the number of yarns wound per unit length of these hollow cables and the outer diameter of the cables.

 [0029] For each of the hollow cables of Examples 3a and 3b, the maximum fixing strength was measured in the same manner as in Example 1. The results are shown in Table 2. For these, the fastening width and fastening thickness were measured in the same manner as in Example 1. The results are shown in Table 3.

[0030] [Table 1]

Table 1. Number of yarn turns and cable outer diameter

 d: Denier

 [0031] [Table 2]

 Table 2. Maximum fixed strength (unit: N)

 [0032] [Table 3]

 Table 3. Width at fastening and thickness at fastening (Unit: mm)

[0033] From Tables 2 and 3, the hollow cables of Examples;! To 3 show sufficient maximum fixing strength in the state of doubled loops widely used in bone fastening, and are tensioned after fastening. And in the state of being crushed, it is deformed into a tape shape and the entire pipe has a round pipe for a tensile tester. It can be seen that it touches the surface of the bone (and therefore the bone surface when the bone is fastened).

Industrial applicability

 The hollow cable for bone fastening according to the present invention is easy to handle in bone fastening, has a low risk of causing bone depression or cutting, can be prevented from twisting, is easy to prevent contact with the spinal cord during spinal surgery, and is excellent. It can be used as a bone fastening cable.

Claims

The scope of the claims  [1] A bone fastening hollow cable formed by braiding fibers into a tube having a substantially circular cross section, which can be crushed and deformed into a belt shape by fastening an object to be fastened.  [2] The hollow cable for fastening bone according to claim 1, wherein the ratio of the outer diameter to the inner diameter is 1.;! ~ 2.0. Yes  [3] The hollow cable for fastening bone according to claim 1 or 2, wherein the inner diameter is 1.0 to 10. Omm. 4. The bone fastening hollow cable according to claim 1, wherein the fiber is an organic fiber and / or an inorganic fiber.  [5] The organic fiber is one or more fibers selected from the group consisting of polyolefin, polyamide, polyacrylonitrile, and silk, and the inorganic fibers are selected from the group consisting of titanium, a titanium alloy, and stainless steel. The bone fastening hollow cable according to claim 4, wherein the hollow cable is one or more fibers.  [6] The bone fastening hollow cable according to any one of claims 1 to 5, wherein the hollow cable is formed by plain weaving or oblique weaving of fibers.