JPH09122160A - Artificial intervertebral spacer - Google Patents

Abstract

(57) [Abstract] [Problem] When performing prosthesis between bones in which a part of the spine is resected, there is no loss of reduction diameter and pain due to non-union,
In addition, bone fusion is good, infection is not caused, and it is safe.
Make it easy to determine bone union using radiographic images. An intervertebral spacer 1 is installed in front of the intervertebral space,
In addition, in order to use the autogenous bone with a large mother bed so that it can be used in combination with the autogenous bone, its shape was made substantially arcuate in plan view.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prosthesis member used in the field of orthopedic surgery, in which a portion of the spine destroyed by a disease such as a bone tumor, a herniated disc, or a traffic accident or disaster is excised. The present invention relates to an artificial intervertebral spacer adapted to be fitted with a self-collected autogenous bone for prosthesis.

[0002]

2. Description of the Related Art The spine of a human body has a structure in which cancellous bone is covered by cortical bone and intervertebral discs made of soft bone are alternately stacked.

In the treatment of diseases such as herniated intervertebral discs in the spine of the human body, the intervertebral discs are removed, and the vertebral bodies are connected and fixed to each other so as to maintain the space between them. Have been used in combination.

As such a spacer, for example, a spacer made of alumina ceramic as described in Japanese Utility Model Publication No. 63-30057, or JP-A-64-76851.
Some of them are made of a metal material as described in JP-A-6-285099, and some of which are made of an ultra-high molecular material as described in JP-A-6-285099.

[0005]

Problems to be Solved by the Invention When autologous bone is used among the above-mentioned conventional techniques, collapse of autologous bone occurs, which often results in loss of reduction diameter and pain due to pseudo-joint, which cannot be performed in elderly patients with osteoporosis. It was

On the other hand, in the case of replacing the intervertebral disc with a spacer alone as the spacer and prosthesis, when an elastic material such as ultra-high polymer material or metal is used, the vertebral bodies above and below the intervertebral body are relatively large. Since it is relatively movable with a large degree of freedom, there is a risk that bacteria may enter the microspace generated by such movement and become infected.

As a technique of using the autologous bone and the spacer together, for lumbar intervertebral disc disease and the like, an elongated spacer is installed in the central portion of the intervertebral space by a posterior approach interbody fusion technique, so-called PLIF-Croward method. , There was a method of implanting autologous bones on the left and right sides, but the shape of the vertebral body is not necessarily symmetrical, and instability due to the difference between the vertebral bodies (wobble etc.)
Therefore, bone union may be hindered, and there is a problem that it is difficult for the spacer to determine bone union in a side X-ray image.

[0008]

Therefore, the present invention is safe because it does not cause the reduction of the reduction diameter and the pain caused by pseudo-joint, and the bone fusion is good and the infection does not occur, and it is easy to judge the bone fusion on the lateral radiographic image. It is an object to provide an intervertebral spacer.

[0009]

In order to solve the above-mentioned conventional techniques, the present invention installs an intervertebral spacer in front of the intervertebral space and takes a large bed of the autologous bone for use with the autologous bone.
The shape was made substantially arcuate in plan view, and a through hole was provided to connect the upper and lower surfaces in contact with the upper and lower vertebral bodies.

[0010]

The vertebral body spacer of the present invention, which has a substantially arcuate shape in plan view, is installed in the anterior intervertebral space as described above, and a space for inserting the autologous bone is surely secured in the central part and posterior part of the intervertebral space. Then, the autogenous bone is packed in this space to replace the natural intervertebral disc. For instability due to anterior-posterior flexion motion, a spinous process plate is also used to limit the relative motion of the vertebral bodies above and below the intervertebral space.

Since the vertebral body spacer of the present invention has a substantially arcuate shape in plan view, it can cover substantially the entire left and right width between the vertebrae and can also cover the front and rear width by about half. It is possible to avoid instability (wobble, etc.) due to the left-right difference. Therefore, bone union occurs early and bacterial infection does not occur.

Further, since only the autologous bone is embedded in the posterior part of the intervertebral space, it is easy to judge the bone union from the lateral radiographic image.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an artificial intervertebral spacer (hereinafter abbreviated as spacer) 1 according to the present embodiment. As shown in the drawing, the spacer 1 has a substantially arc shape in a plan view. Here, the substantially arc shape means a curved arc shape in which the ratio of the major axis l to the minor axis s is 2 or more.

As a material for forming the spacer 1,
A ceramic material such as alumina or zirconia, an ultra-polymer material such as high-molecular polyethylene, a metal material such as a titanium mesh block, or a combination thereof may be used. In particular, from the viewpoint of fixation with bone, a surface layer made of a calcium phosphate-based material such as apatite or an osteophilic material such as collagen is provided on the joint surface with bone, or the titanium mesh block is arranged on the side in contact with bone. It may be one.

FIG. 2 shows a state in which the spacer 1 is used. The spacer 1 having a substantially arcuate shape in plan view is installed in front of the intervertebral space J as described above, and the autologous bone T is located in the central portion and posterior of the intervertebral space J.
After securing a space for inserting the bone, the autogenous bone T is packed in this space. In this way the natural disc is replaced. Further, for instability due to anteroposterior flexion motion, the spinous process plate B is also used to limit the relative motion of the vertebral body F located above and below the intervertebral space J.

Since the spacer 1 of the present invention has a substantially arcuate shape in a plan view, it can cover substantially the entire left and right width between the vertebrae and can also cover the anteroposterior width by about half. By using it together with the autologous bone T,
The vertebral body F has such a size and shape as to avoid instability (wobble or the like) due to the left-right difference. Therefore, bone union occurs immediately and bacterial infection does not occur.

Further, since only the autologous bone T is embedded in the posterior part of the intervertebral space J, the side face X can be seen from FIG.
It is easy to judge the bone union from the radiographic image.

Next, as shown in FIG. 2 (b), the spacer 1 communicates between the upper surface 2 and the lower surface 3 and has a through hole 4 having a size sufficient for filling a small piece of autogenous bone. Have
Bone fusion between the upper and lower vertebral bodies F and the autologous bone T is supplementarily strengthened. Although FIG. 1 shows the through-hole 4 having a planar shape similar to the outer shape of the spacer 1,
When such a through hole 4 is provided, its shape is arbitrary as long as it has a size sufficient to fill the small piece of autogenous bone T as described above. In addition, such a through hole 4
Whether or not to provide is also optional.

A plurality of spikes 5 are provided on each of the upper and lower surfaces of the spacer 1 so that the spacer 1 will not be displaced in the initial stage after the spacer 1 is installed and the autologous bone T is transplanted. It is devised to be. As shown in FIG. 3, the spike 5 has a truncated quadrangular pyramid shape in which the tip is tapered with respect to the base portion, and the size thereof is 0.5 to 1 mm in height and one side length of the base portion 1 .5-2.
About 5 mm is suitable.

The shape of the spike 5 is not limited to the truncated quadrangular pyramid shape, and may be a conical shape with a rounded tip as shown in FIG. 4, a pyramid shape, or any other shape. . As in the above case, the size in these cases is preferably 0.5 to 1 mm in height, and the length or diameter of one side of the base portion, the major axis, etc. is about 1.5 to 2.5 mm.

[0021]

As described above, the artificial intervertebral spacer of the present invention is installed in front of the intervertebral space and its shape is seen in a plan view in order to make the mother bed of the autogenous bone large so as to be used together with the autogenous bone. It is a substantially arcuate shape, and with such a configuration it can cover almost the entire left and right width between the vertebrae and can also cover about half of the anterior and posterior width.In combination with autologous bone, instability due to the difference in the vertebral body left and right (Wobble etc.) can be avoided. Therefore, it has an excellent effect that bone union occurs immediately and bacterial infection does not occur.

Further, according to the spacer of the present invention, since only the autologous bone is embedded in the posterior part of the intervertebral space, it is possible to easily determine the bone fusion in the lateral radiographic image.

[Brief description of the drawings]

FIG. 1 shows an artificial intervertebral spacer according to an embodiment of the present invention, in which (a) is a top view and (b) is a side view.

FIG. 2 shows a state of use of the artificial intervertebral spacer of FIG.
(A) is a side view of an installation place, (b) is a sectional view taken along the line AA.

3 shows spikes provided on the artificial intervertebral spacer of FIG. 1, (a) being a top view and (b) being a side view.

FIG. 4 is a perspective view showing another example of the shape of the spike shown in FIG. 3, where (a) is a spike having a conical shape with a rounded tip;
Is a pyramid-shaped spike.

[Explanation of symbols]

 J Intervertebral T Autogenous bone B Spinous process plate F Vertebral body s Short diameter 1 Long diameter 1 (Artificial intervertebral space) Spacer 2 Upper surface 3 Lower surface 4 Through hole 5 Spike

Claims (2)

[Claims] 1. A spacer, which is inserted between bones from which a part of the spine has been resected to be inserted together with autologous bones for prosthesis, has a substantially arc shape in plan view, and is in contact with upper and lower vertebral bodies. An artificial intervertebral spacer having a through hole communicating between lower surfaces. 2. The artificial intervertebral spacer according to claim 1, wherein a plurality of fixing spikes are formed on the upper and lower surfaces in contact with the upper and lower vertebral bodies.