JPH10165412A - Spacer for atlas and axis fixing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to fix the atlas and the axis in both vertical and rotational directions with simple operation, by constituting a spacer for atlas fixing by a screw member to be horizontally inserted in between the atlas and the axis from the rear side and fixing the screw member with the atlas and the axis by screwing. SOLUTION: In a condition a spacer 1 is inserted between vertebras 55, a screw part 12 is screwed with an atlas 5 and an axis 6 to fix the atlas 5 and the axis 6 so as not be moved in the front-back direction and relatively rotate between the vertebras 55. At that time, the spacer 1 is used together with a clamp 3 which vertically clamps and holds the atlas and the axis, hook- shaped hooks 31, 32 are oppositely placed, the interval is adjusted by an adjusting screw part 33, hooks 31, 32 are hooked on arches of vertebra 52, 62, the interval between hooks 31, 32 is narrowed by the adjusting screw part 33, and the atlas 5 and the axis 6 are clamped in the vertical direction to be fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer for fixation of atlanto-axial vertebrae, which is inserted between vertebrae to fix the atlantic and axial vertebras displaced by subluxation or the like.

[0002]

2. Description of the Related Art Conventionally, as a fixation method when the atlas (first cervical vertebra) and the axial vertebra (second cervical vertebra) are displaced due to subluxation or the like, a wire grafted between the atlantic vertebra and the axial vertebra is inserted. There is known a bone grafting method in which the screw is fastened and fixed, and a Margel method in which a screw is penetrated obliquely from below the axial vertebra toward the atlas to screw and fix the two. However, in the bone transplantation method, it is necessary to perform a separate operation for collecting the transplanted bone, and in the Margel method,
Since it is necessary to screw the screw so as not to touch the blood vessels and nerves around the atlas and axial vertebra, there is a problem that the operation is difficult and the operation time is long.

Therefore, in recent years, a method has been proposed in which the atlas and the axial vertebra are fixed in a vertical direction by using a metal clamp (so-called hook method). The clamp is provided with a pair of key-shaped hooks, and the hooks are configured to be hooked on the arcuate portions of the atlas and the axial vertebra (the vertebral arch) and fastened.

[0004]

Here, the atlas and axial vertebrae are parts that rotate relative to each other as the human body turns, but in a procedure such as subluxation, it is necessary to fix them so that they do not rotate. However, the clamps tightened in the vertical direction as described above have a problem that a force for fixing the atlas and the axial vertebra in the rotational direction is weak.

The present invention has been made in view of the above circumstances, and has as its object to enable the atlas and the axial vertebra to be fixed in the vertical and rotational directions by a simple operation.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a spacer for fixation of atlanto-axial vertebrae by means of a screw member which is horizontally inserted from the back between the atlas and the axial vertebra. By screwing the screw member with the atlas and axial vertebra,
The structure is such that the atlas and the axial vertebra are fixed so as not to move relatively in the longitudinal direction.

Since the vertebrae are located on the left and right with respect to the axis of relative rotation between the atlas and the axial vertebra, if the atlas and the axial vertebra are fixed so as not to move in the anteroposterior direction between the intervertebral vertebrae as described above, the The vertebra and the axial vertebra can be fixed so as not to rotate relative to each other.
Therefore, when used together with a clamp for clamping and fixing the atlas and the axial vertebra from above and below, the atlas and the axial vertebra can be more reliably fixed in the rotational direction and the vertical direction.

When the length of the screw member is set to 4 mm or more and 12 mm or less, the screw member does not horizontally project in a state where the screw member is fitted between the atlanto-vertebrae.
When the outer diameter of the screw member is 4 mm or more and 7 mm or less, and the diameter of the valley is 3 mm or more and 5 mm or less, the screw member is securely inserted in the state of the interaxial vertebrae. It can be screwed into the atlas and axial vertebra.

The screw member has no head and a hexagonal hole at the rear end (so-called set screw with hexagonal hole).
It can also be configured as Since the screw member does not have a head, there is no portion that protrudes backward with the screw member inserted between the atlas and the axial vertebra. Also, because it has a hexagonal hole,
When the screw member is inserted between the intervertebral vertebrae, the screw member can be rotated using a thin hexagonal wrench.

Further, when the screw member is formed as a self-tapping screw having a tapered portion at the distal end and a notch at the distal end, the screw member is inserted into the intervertebral vertebrae by rotating the screw member while rotating. It becomes possible to screw into the female screw while working the female screw between vertebrae.

Further, if a through hole is formed at the radial center of the screw member so as to penetrate the screw member in the axial direction, a guide between the vertebrae can be inserted when the spacer is inserted between the atlas and the axial vertebra. Since the wire can be inserted in advance and the spacer can be fitted in a state where the guide wire is passed, the spacer can be easily and reliably guided to the destination. In addition, if it is comprised so that the space between adjacent screw threads may become circular, the bite with respect to the atlas and axial vertebra will improve, and it becomes possible to form a female screw easily between vertebrae. Also,
If the spacer is made of a titanium alloy, the compatibility with the living body is good.

[0012]

Next, an embodiment of the present invention will be described. 1 and 2 are perspective views showing the atlas 5 (first cervical vertebra) and the axial vertebra 6 (second cervical vertebra) and the atlas for fixation 1 of the embodiment. As shown in FIG.
The intervertebral space 55, which is the joint surface between the vertebrae 6 and the shaft vertebra 6, is located on the left and right with respect to the rotation axis O accompanying the turning of the human body (only the left intervertebral space 55 is shown in FIG. 1). The spacer 1 for fixation of the atlantoaxial vertebrae of the embodiment is configured as a screw member which is horizontally fitted into the left and right vertebrae 55 from behind.

FIG. 2 is a perspective view of the spacer 1, and FIG.
4 and FIG. 4 are a side view and a front view of the spacer 1. The spacer 1 is a screw member having a hexagonal hole 11 that engages with a hexagonal bar wrench (not shown) at the rear end in the axial direction, and has no head. That is, the spacer 1
This is a so-called hexagon socket set screw that is completely housed in the internal thread without projecting the head when screwed into a predetermined internal thread.

As shown in FIGS. 3 and 4, a tapered portion 13 is provided at the axial end of the spacer 1. In addition, two notches 14 such as groove taps are formed at the tip portion including the tapered portion 13. That is, when the spacer 1 is screwed into a predetermined pilot hole, the notch 14 bites into the inner surface of the pilot hole and is screwed together with the screw portion 12 while screwing the inner surface. That is, the spacer 1 is a so-called self-tapping screw.

Further, a through hole 15 is formed at the radial center of the spacer 1 to penetrate the spacer 1 in the axial direction. The through-hole 15 is used for inserting a guide wire, which will be described later, during the work of inserting the guide wire into the intervertebra 55 (FIG. 1). The spacer 1 is made of a titanium alloy having a good affinity with a living body.

Next, the dimensions of the spacer 1 will be described. FIG. 5 shows the spacer 1 between the atlas 5 and the axial vertebra 6.
It is a sectional side view showing the state where it was fitted in. The width H of the vertebra 55 in the front-rear direction is generally about 20 mm. for that reason,
The overall length L (FIG. 3) of the spacer 1 is set to be not less than 4 mm and not more than 12 mm so that the spacer 1 completely fits inside the intervertebral disc 55 and does not protrude backward from the intervertebral disc 55.

The interval D between the vertebrae 55 shown in FIG. 5 is generally about 2 mm. Therefore, the screw portion 12 of the spacer 1 is screwed into the atlas 5 and the axial vertebra 6.
Has an outer diameter A (FIG. 3) of not less than 4 mm and not more than 7 mm,
The diameter B (FIG. 3) of the valley of the screw portion 12 is set to be 3 mm or more and 5 mm or less.

Since there are individual differences in the dimensions of the intervertebra 55, a plurality of types of dimensions of the spacer 1 are set. Table 1 below shows examples of combinations of the overall length L of the spacer 1 of the present embodiment, the outer diameter A of the threaded portion, and the root diameter B of the threaded portion. Note that L,
As long as A and B are within the above ranges, combinations other than Table 1 are also possible.

[0019]

[Table 1] L (mm) A (mm) B (mm) 8.0 5.0 3.5 8.0 5.5 3.5 10.0 6.0 4.0 10.0 6.5 4.5

In the spacer 1 thus constructed, the screw portion 12 is inserted into the intervertebra 55 so that the screw portion 12 has the atlas 5 and the axial vertebra 6.
Therefore, the atlas 5 and the axial vertebra 6 in the intervertebral space 55 are fixed so as not to relatively move in the front-rear direction. for that reason,
As shown as a rear view in FIG. 6, the spacer 1 is fitted into the left and right vertebrae 55, and the atlas 5 and the axial
Can be fixed so that the atlas 5 and the axial vertebra 6 do not rotate relative to each other (indicated by the arrow R).

Here, as shown in FIGS. 5 and 6, the spacer 1 is used together with a clamp 3 for holding the atlas 5 and the axial vertebra 6 with scissors from above and below. The clamp 3 includes two key-shaped hooks 31 and 32. The two hooks 31 and 32 are arranged to face each other, and the distance between them can be adjusted by an adjusting screw 33.

The hooks 31 and 32 are connected to the atlas 5 and the shaft 6.
The atlas 5 and the axial vertebra 6 can be fastened and fixed in the vertical direction by being hooked on the vertebral arches 52, 62, which are the arcuate portions of the above, and narrowing the distance between the hooks 31, 32 by the adjusting screw portion 33. it can. That is, the atlas 5 and the axial vertebra 6 are fixed in the up-down direction by the clamp 3 and fixed.
By fixing the atlas 5 and the axial vertebra 6 by the spacer 1 so as not to rotate relative to each other, the atlas 5 and the axial vertebra 6 can be more reliably fixed.

Next, a method of fitting the spacer 1 into the intervertebral space 55 will be described with reference to FIG. As shown in FIG. 7A, a guide wire 4 for guiding the spacer 1
1 is inserted into the intervertebral space 55. The guide wire 41 is inserted through the through-hole 15 of the spacer 1 shown in FIG. 3 and reliably guides the spacer 1 to the vertebra 55. The tools used for the work of inserting the spacer 1 are formed with through holes similar to the through holes 15 of the spacer 1 so that the tools can be easily and reliably guided to the intervertebra 55.

After the guide wire 41 is inserted, FIG.
Drill 4 along guide wire 41 as shown in FIG.
2 is inserted and a pilot hole is machined in the intervertebral space 55. Then, FIG.
As shown in (c), the spacer 1 is fitted into the prepared hole 58 formed by the drill 42. The spacer 1 has a hexagonal bar wrench 45 fitted in the hexagonal hole 11 (FIG. 2) at the rear end.
Is rotated. Since the spacer 1 is a self-tapping screw, the spacer 1 is fitted into the pilot hole 58 while being rotated by a hexagonal bar wrench 45 so that the pilot hole 5 is formed.
An internal thread is machined into 8, and the spacer 1 is screwed into the internal thread.

Here, since the notch 14 (FIG. 3) is formed at the tip of the spacer 1, the inner surface of the pilot hole 58 is easily bitten. In addition, the screw portion 12 is formed with the adjacent screw thread 1.
2 is formed so as to have a semi-circular cross section (indicated by r in FIG. 3), and the threads are formed at an acute angle, so that the threads can easily bite into the inner surface of the pilot hole 58, and are simple. A female screw can be formed in the pilot hole 58. In addition, before the spacer 1 is fitted into the prepared hole 58, it is also possible to perform preliminary screw processing on the prepared hole 58.

When the spacer 1 is fitted almost to the center of the intervertebral space and the spacer 1 is completely accommodated in the intervertebral space 55 without protruding backward, the guide wire 41 is inserted into the intervertebral space 5.
5 and the work of inserting the spacer 1 into the intervertebral space 55 is completed. After the work of inserting the spacer 1 is completed, the work of tightening and fixing the atlas 5 and the axial vertebra 6 by the clamp 3 is performed, but the description thereof will be omitted.

Thus, according to the present embodiment, the intervertebral 5
By screwing the spacer 1 fitted into the 5 to the atlas 5 and the axial vertebra 6, it becomes possible to fix the atrial 5 and the axial vertebra 6 so as not to rotate relative to each other. Therefore, when used together with the clamp 3 for sandwiching and fixing the atlas 5 and the axial vertebra 6 from above and below, the atrial 5 and the axial vertebra 6 can be reliably fixed in the rotational direction and the vertical direction. In addition, since the spacer 1 does not protrude backward from the intervertebral space 55, it does not interfere with other tissues or clamp attachment.

[0028]

As described above, according to the present invention,
The atlas for fixation of the atlas is constituted by a screw member which is horizontally inserted between the atlas and the axial vertebra from behind, and the screw member is screwed into the atlas and the axial vertebra to form the atlas and the axial vertebra. Can be fixed so as not to relatively move in the front-rear direction. Since the vertebrae are located on the left and right with respect to the axis of relative rotation between the atlas and the axial vertebra, if the intervertebral vertebrae and the axial vertebra are fixed in the anteroposterior direction between the intervertebral vertebrae as described above, the relative vertebrae and the axial vertebra can be relatively positioned. Can be fixed so that it does not rotate. Therefore, when used together with a clamp for clamping and fixing the atlas and the axial vertebra from above and below, the atlas and the axial vertebra can be more reliably fixed in the rotational direction and the vertical direction.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a spacer for fixing a collar shaft, a collar vertebra, and a shaft vertebra according to an embodiment.

FIG. 2 is a perspective view of the ring shaft fixing spacer of FIG. 1;

FIG. 3 is a side sectional view of the ring shaft fixing spacer of FIG. 1;

FIG. 4 is a front view of the ring shaft fixing spacer of FIG. 1;

FIG. 5 is a side sectional view showing a state where the spacer for fixation of the collar shaft of FIG. 1 is fixed between the vertebrae of the collar shaft vertebra.

FIG. 6 is a rear view showing a state in which the spacer for fixation of the shaft of FIG. 1 is fixed between the vertebrae of the shaft.

FIG. 7 is a side sectional view showing an operation of fitting the spacer for fixation of the collar shaft of FIG. 1 into the intervertebral region of the collar shaft vertebra.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spacer 11 Hexagon hole 12 Screw part 13 Taper part 14 Notch 15 Through-hole 3 Clamp 31, 32 Hook 33 Adjustment screw part 5 Atlas 55 Intervertebral 6 Axle

Claims (11)

[Claims] 1. A screw member that is horizontally inserted from behind between the atlas and the axial vertebrae, and the screw member is screwed with the atlas and the axial vertebra in the intervertebral space. An atlas for fixation of atlantoaxial vertebrae, wherein the spacer is fixed so as not to move relative to the axial vertebra in the front-rear direction. 2. The length of the screw member is 4 mm or more and 12 mm or more.
2. The spacer for fixation of atlantoaxial vertebrae according to claim 1, wherein the distance is less than millimeter. 3. The spacer for atlas fixation according to claim 1, wherein an outer diameter of the screw member is 4 mm or more and 7 mm or less. 4. The root diameter of the screw member is 3 mm or more and 5 mm or more.
The spacer for atlas fixation according to any one of claims 1 to 3, wherein the distance is equal to or less than millimeter. 5. The ring according to claim 1, wherein the screw member has a hexagonal hole and has a hexagonal hole at a rear end without a head. Spacer for shaft fixation. 6. The spacer for fixating atlantoaxial vertebrae according to claim 1, wherein the screw member has a tapered end portion. 7. The spacer for atlas fixation according to claim 1, wherein the screw member is a self-tapping screw having a notch at a tip end. 8. The ring according to claim 1, wherein a through-hole penetrating the screw member in an axial direction is formed at a radially central portion of the screw member. Spacer for shaft fixation. 9. The screw member according to claim 1, wherein a section between adjacent screw threads is formed in a semicircular shape in a cross section along a central axis of the screw member. A spacer for fixation of atlantoaxial spine according to item 1. 10. The spacer for atlas fixation according to claim 1, wherein the screw member is made of a titanium alloy. 11. The atlantoaxial fixation according to claim 1, wherein the spacer is used in combination with a clamp for holding the atlas and the axial vertebra vertically. Spacer.