JP4242855B2 - Implant for fixation - Google Patents

Description

  The present invention mainly aims at embedding into a skeleton in the treatment of the skeleton such as fracture treatment, spinal fixation / correction treatment, treatment of osteoporosis / spine tumor / spondylitis, etc., and a cleaning agent such as water or physiological saline in the bone The present invention relates to a fixing implant (hereinafter sometimes simply referred to as “implant”) that is convenient for injecting a filling material such as a drug, a prosthetic agent, and a biological tissue regeneration treatment substance.

  Conventionally, in order to inject a filler into a bone, for example, first, a predetermined hole is drilled in the bone, the filler is injected into the hole, and then a screw-like implant is screwed into the hole and fixed. Was adopted. In addition, in the screw-like implant, there is also proposed an implant in which a hollow hole extending to the distal end portion thereof is formed and a lateral hole extending from the hollow hole to the outer side portion of the implant is provided, and a filling material is injected from the hollow hole. It was.

  However, in the conventional filling method described above, as the screw-like implant is screwed in, the injected filling material appears, and the filling amount becomes less than expected or spreads to an undesired site. There was an inconvenience. In addition, due to such inconveniences, the conventional fixing method using screw-like implants for osteoporosis has a problem that the implants may be loosened.

  Further, regarding the implant provided with the hollow hole, when the implant is used as a transpedicle implant for posterior spinal fixation, depending on the shape of the tip and the position of the extraction hole, the following adverse effects are exerted on the human body. There is a risk that

  That is, when the hollow portion penetrates from the head to the tip of the implant, if the implant is screwed by piercing the anterior vertebral body cortex due to a mistake in the procedure, the filler injected from the head Can be pumped through the hollow and anterior to the vertebral body, which can adversely affect organs such as the respiratory, large blood vessels, and digestive organs in the thoracic or abdominal cavity.

  In addition, when the extraction hole formed on the side surface of the implant shaft is formed to the vicinity of the implant head, if the implant is pierced through the pedicle medial bone cortex due to a mistake in the procedure, the head is The filler injected from the inside is poured into the spinal canal through the outlet hole and may adversely affect the spinal cord, cauda equina, nerve root, and the like.

  Therefore, as a result of intensive research, the present inventor can inject a predetermined amount of filling material into a desired site even when both a fixation implant and filling material injection are used together. We have developed an implant for fixation in which the shape of the tip and the position of the extraction hole that can avoid these are identified.

The fixation implant according to the present invention is an axial fixation implant having a head portion and a tip portion, and an injection hole is formed in the head portion, and a hollow portion communicating from the injection hole in the tip direction from the head portion, It is formed so as not to penetrate the distal end portion of the fixing implant, and the distal end portion of the fixing implant is made a blind end, and only in the range of 5 to 20 mm in the head direction from the distal end portion of the fixing implant, The present invention is characterized in that a filling hole formed by forming one or a plurality of extraction holes communicating with the hollow portion is provided.

  The fixing implant may have a tapered shaft shape from the head side toward the tip, and may be a screw having a surface threaded, or a tapered wedge shape from the head side toward the tip. None, the surface may be non-slip processed.

  By constructing the implant for fixation as described above, after the implant is screwed or driven into a predetermined place, the filling material is injected from the injection hole of the head, and the filling material leads the hollow portion of the implant from the head. It moves in the direction, and the filling material is pushed out from the side surface of the shaft portion of the implant and filled into the bone.

  Moreover, since the hollow portion formed from the implant head is not penetrated to the tip and is made a blind end, it is possible to avoid the filling material being poured out to the front of the vertebral body even when the implant pierces the front of the vertebral body.

  Furthermore, since the position of the extraction hole on the side surface of the shaft portion is within 20 mm in the head direction from 5 mm to the tip of the implant, the extraction hole is limited within the vertebral bone marrow by forming the extraction hole within this range. However, since it is not formed at a position corresponding to the pedicle portion, it is possible to avoid a risk that the filling material is poured into the spinal canal even when the implant pierces the pedicle inner bone cortex.

  Further, as the fixation implant according to the present invention, the extraction hole may be provided in a direction orthogonal to the long axis direction of the fixation implant, and the extraction hole is a long axis of the fixation implant. You may make it provide in the some direction orthogonal to a direction. In particular, in the latter case, since the filler is poured out in a plurality of directions, it can be expected that the strength is increased with respect to the compression force from multiple directions.

Since the fixing implant according to the present invention is provided with a filling hole that leads from the head to the side surface through the hollow portion as described above, a filling material of a predetermined filling amount can be injected into a desired site. This solves the conventional inconvenience. In addition, the fixing implant specifies the shape of its distal end , and the position of the dispensing hole is specified only in the range of 5 to 20 mm in the head direction from the distal end of the fixing implant. All the dangers predicted by the are avoided, so that high safety is ensured. As a result, the possibility of loosening of the implant in the fixation method using a screw-like implant for osteoporosis was solved. It has also become possible to inject therapeutic drugs directly into the lesion for spinal tumors and spondylitis.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, although an Example demonstrates the screw-type screw-shaped fixing implant, it is applicable also to a drive-in wedge-shaped fixing implant.

  FIG. 1 is a perspective view showing a first embodiment of an implant screw as a fixation implant according to the present invention, FIG. 2 is a partially cutaway perspective view of FIG. 1, and FIG. 3 is screwed into the spine. FIG. 4 is a schematic diagram showing a state in which the filler is injected, and FIG. 4 is a schematic diagram showing a state in which the filler is connected after the filler is injected.

  In FIG. 1 and FIG. 2, A is an implant screw and includes a head 10 and a screw shaft portion 20. The head 10 is threaded at its inner periphery, and is formed with a U-shaped groove 11 through which the rod B is passed. The screw shaft portion 20 has a tapered shaft shape from the head side toward the tip, and a screw thread 21 is threaded on the surface of the screw shaft portion 20. The shape can be screwed. Note that the screw for implant is not limited to the one shown in the figure, and the present invention is of any type as long as it is an axial implant having a head and a tip for insertion into a bone. However, it is possible to adopt, for example, a screw-like surface threaded as in this embodiment, not to be tapered, and the surface is not threaded, from the head side to the tip. It may be formed in a tapered wedge shape and its surface is anti-slip processed.

  The screw A is provided with a filling hole 30 penetrating the screw A. The filling hole 30 is composed of an injection hole 31, a hollow part 32, and a pouring hole 33. The injection hole 31 is formed at the axial center position of the head portion 10, the hollow portion 32 communicates with the injection hole 31, and is formed in the screw shaft portion 20 from the head portion 10 toward the distal end. The hollow portion 32 is formed on the screw shaft. It is formed so as not to reach the distal end portion 22 of the portion 20 and to continue to the extraction hole 33 that communicates from the hollow portion 32 to the outside of the side surface of the screw shaft portion 20. The dispensing hole 33 is a direction orthogonal to the major axis direction of the screw A and a direction orthogonal to the groove direction of the U groove 11, and is between 10 mm and 15 mm in the head direction from the tip of the screw A. It has a long hole shape with a length of 5 mm. Accordingly, the filling hole 30 is configured such that the filling material injected from the injection hole 31 of the head 10 passes through the hollow portion 32 and is poured out of the side surface of the screw shaft portion 20 from the extraction hole 33. Yes. In the present embodiment, the extraction holes 33 are provided at two locations on the side of the side surface of the screw shaft portion 20, but the position of the extraction hole is within 5 mm from the tip of the screw A in the head direction of 5 mm or more. As long as it is provided in the range, the number and shape thereof are not limited to this, and the design can be changed as appropriate.

  As shown in FIG. 3, the screw A having the above configuration is screwed into a spine C into a guide hole formed by a surgical drilling instrument such as a drill, an owl, or a probe, and then the filler is screwed into the screw A by an injector. The filling material is injected from the injection hole 31 of the head 10 and the filling material is discharged through the hollow portion 32 of the screw A to the outside of the side surface of the screw shaft portion 20 from the extraction hole 33. Therefore, if this screw A for implants is used, it can fully inject | pour the filling of the filling amount which is due to be inject | poured into a desired site | part without shortage.

  At this time, the hollow portion 32 formed from the head 10 of the screw A is blinded without penetrating to the tip, so that the filling material is forward of the vertebral body even when the tip of the screw A pierces the vertebral body forward. Being dispensed is avoided.

  Furthermore, since the extraction hole 33 on the side surface of the shaft portion 20 is a 5 mm long hole between the tip of the screw A and the head direction of 10 mm to 15 mm, the extraction hole 33 is limited in the vertebral body bone marrow, and the vertebral arch Since it is not formed at a position corresponding to the root portion, the risk that the filler is poured into the spinal canal is avoided even when the screw A pierces the pedicle medial bone cortex.

  Further, the dispensing hole 33 in the screw A in the present embodiment is provided in a direction orthogonal to the groove direction of the U groove 11, and the rod B is linearly formed in the U groove 11 of each screw A as described below. Since the groove direction of the U-groove 11 needs to be aligned and screwed in the vertical direction, the filling hole 33 of each screw A is in the horizontal direction, so that the filling is horizontal in the vertebral body (as viewed from the human body). (Inside and outside direction). Therefore, in this case, since the rotation of the screw A in the vertebral body can be suppressed, there is an advantage that the skeleton can be reliably fixed by the connected screw A.

  FIG. 4 shows a state in which the screws A are connected to each other by passing the rod B through the U-groove 11 after the screw A is screwed into the spine C and the filling material is injected as described above. Even if it uses the screw A which concerns on an example, it can carry out without changing the conventional connection method at all.

  As described above, the implant screw A according to the present embodiment can be obtained by injecting a filler from the injection hole 31 of the head 10 after the screw A is screwed into a predetermined position. The hollow portion 32 of the screw for use is moved in the distal direction, and the filler is pushed out from the side surface of the screw shaft portion 20 of the screw A to be filled in the bone. Therefore, in the implant screw A, by providing the filling hole 30 that leads from the injection hole 31 of the head portion 10 to the side extraction hole 33 through the hollow portion 32, a filling amount of a planned filling amount can be obtained. The filling can be injected safely and the conventional disadvantages are eliminated.

  FIG. 5 is a perspective view showing a second embodiment of an implant screw as a fixation implant according to the present invention, and FIG. 6 is a schematic view showing a state in which the screw is screwed into the spine and a filling material is injected. is there.

  The screw for implant in the present embodiment is different only in the formation direction of the extraction hole 33 of the screw A in the first embodiment, and the rest of the configuration is the same as in the first embodiment, so only the difference will be described below. And the description of Example 1 is used for common points.

  In FIG. 5, A ′ is an implant screw, and includes a head portion 10 and a screw shaft portion 20. The head 10 is threaded at its inner periphery, and is formed with a U-shaped groove 11 for passing a rod.

  The screw A 'is provided with a filling hole 30 that passes through the screw A'. The filling hole 30 includes an injection hole 31, a hollow part 32, and a dispensing hole 33 '. The dispensing hole 33 ′ is a direction orthogonal to the major axis direction of the screw A ′ and is the same direction as the groove direction of the U groove 11 and is 10 mm to 15 mm in the head direction from the tip of the screw A ′. It is in the shape of a long hole having a length of 5 mm formed therebetween.

  Therefore, since the rod direction of the U groove 11 needs to be aligned and screwed in the vertical direction in order to pass the rod through the U groove 11 of each screw A ′, the dispensing hole 33 ′ of each screw A ′ is in the horizontal direction. Therefore, as shown in FIG. 6, the filling material is dispensed in the vertical direction (the cranial and caudal direction as viewed from the human body) in the vertebral body. Therefore, in this case, since the rotation of the screw A ′ in the vertebral body can be suppressed, there is an advantage that the skeleton can be securely fixed by the connected screw A ′, and the screw A ′ can dispense the filling material. Due to the direction, an increase in strength can be expected with respect to the compression force in the vertical direction against the vertebral body, and by using the screw A ′ in which the extraction hole 33 ′ in the cranial and caudal direction is formed, the treatment of the compression fracture Effective and preventive effect can be expected.

It is a perspective view which shows Example 1 of the implant for fixation which concerns on this invention. FIG. 2 is a partially cutaway perspective view of FIG. 1. It is the schematic which shows the state which screwed the screw which concerns on Example 1 into the spine, and inject | pours a filler. It is the schematic which shows the state connected after inject | pouring a filler into the screw which concerns on Example 1. FIG. It is a perspective view which shows the 2nd Example of the screw for implants as a fixed implant which concerns on this invention. It is the schematic which shows the state which screwed the screw which concerns on Example 2 into the spine, and inject | pours a filler.

Explanation of symbols

A ... Screw for implant B ... Rod C ... Spine 10 ... Head of screw 11 ... U groove on head 20 ... Screw shaft 21 ... Screw shaft Thread on the surface 22 ... Screw tip 30 ... Filling hole 31 ... Injection hole 32 ... Hollow part 33 ... Injection hole A '... Implant screw 33' ..Pouring holes

Claims (5)

In an axial fixation implant having a head and a tip,
An injection hole is formed in the head, and a hollow portion passing from the injection hole in the distal direction from the head is formed so as not to penetrate the distal end portion of the fixation implant, and the distal end portion of the fixation implant is made a blind end. ,
A filling hole formed by forming one or a plurality of extraction holes communicating with the hollow portion on the side surface of the shaft portion is provided only in a range of 5 to 20 mm in the head direction from the distal end portion of the fixing implant. Implant for fixation.   2. The fixation implant according to claim 1, wherein the fixation implant is a screw having a tapered shaft shape from the head side toward the tip, and having a surface threaded.   2. The fixing implant according to claim 1, wherein the fixing implant has a tapered wedge shape from the head side toward the tip, and the surface is anti-slip processed.   4. The fixation implant according to any one of claims 1 to 3, wherein the extraction hole is provided in a direction orthogonal to the major axis direction of the fixation implant.   5. The fixation implant according to any one of claims 1 to 4, wherein the dispensing holes are provided in a plurality of directions orthogonal to the major axis direction of the fixation implant.

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