JPH0698162B2 - Cervical artificial disc - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention inserts between cervical vertebrae in order to repair the cervical vertebrae of a human body,
The present invention relates to an artificial intervertebral disc for fixation.

[Prior art and its problems]

With the advancing age of society, cervical spine aging, pressure disorders of the cervical spinal cord due to degeneration, cervical spondylotic myelopathy and radiculopathy, and cervical spondylitis are increasing every day.

Many of these are very common diseases, as they appear as so-called severe cervical shoulder and arm pain or chronic paralysis of the upper and lower limbs, and most of them occur in the middle-aged and older people over the age of 50 and one or more cervical discs. Based on aging degeneration, subtotal vertebral body resection and transplantation with autologous bone are performed as basic principles of surgical treatment for this.

However, in view of the etiology thereof, extensive cervical spinal fusion surgery is inevitably performed across multiple vertebrae.

In this case, it is not uncommon for the intervertebral discs adjacent to each other in the fixed site to promote the same aging degeneration over time and to have a pathological significance again.

In such a case, it is a serious problem to add the fixing operation to the cervical spine again. Needless to say, cervical spine motility is markedly impaired, resulting in a major obstacle to daily life.

For such a special case, it is naturally required that the cervical spine retains the mobility and the reliable therapeutic effect is enhanced.

[Means for solving problems]

To sandwich the transplanted bone so as not to cause dehiscence of the transplanted bone in cervical intervertebral fusion to repair the cervical spine disorder as described above,
The problem is solved by inserting an artificial intervertebral disc made of a ceramic material that is permanently embedded between the vertebral bodies adjacent to the upper and lower cervical vertebrae.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

1 (a), (b), and (c) are front views of an artificial intervertebral disc for cervical vertebrae (hereinafter simply referred to as an artificial intervertebral disc) 1 as an example, a cross-sectional view taken along line YY in FIG. The figure is shown. This artificial intervertebral disc 1 is made of alumina, zirconia, which has in vivo stability such as biocompatibility, mechanical strength, and corrosion resistance.
Made of ceramic material such as apatite, width W = 10-12mm, depth D = 10 to fit the size of the cervical spine to be inserted.
Approximately 18 mm and a height H = 4 to 10 mm, forming a substantially columnar body.

In addition, a plurality of protrusions 2 are integrally formed on the lower surface of the artificial intervertebral disc 1, and the front surface has a hole for improving the gripping property by the instrument when inserting it between the cervical vertebrae and for ensuring the positioning. 3 and a recess 4 are formed.

Further, a saddle-shaped curved surface 5 having a groove is formed on the upper surface. The hole 3 may be penetrating, and the projection 2 may be conical or triangular.
Alternatively, a combination of these various shaped protrusions or a plurality of ridges having sharp pointed ends may be formed.
Further, the overall shape of the artificial intervertebral disc 1 is not limited to the square columnar body described above, and may be a columnar body.

Next, an example of use of the above-described artificial disc 1 of the present invention will be described with reference to the drawings. FIG. 3 shows a side view of the cervical vertebrae of the human body.
It consists of C ₁ , C ₂ , ... C ₇ , and the spinal cord S exists in these cervical vertebrae.

Now, if the intervertebral disc E between the vertebral bodies C ₄ and C ₅ is deformed or moved, and the tip of the intervertebral disc presses the nerve in the spinal cord S, that is, if a symptom such as a herniated disc or a shivering occurs, the position of the disc E is corrected. It has been performed as a general surgical procedure to remove the protruding portion.

However, for this kind of surgical procedure, there is a high probability that exactly the same condition will recur, and it will be necessary to perform the same operation again, and not only the patient's pain burden will be very large, but also Since then, there has been a guarantee that similar diseases will not occur.

Therefore, as a surgical treatment for the first disease, after removing the intervertebral disc E, the vertebral bodies C ₄ and C ₅ are directly connected to each other, and the vertebral bodies C ₃ and C ₄ or the adjacent vertebral bodies C ₆ and C ₇ are connected. Artificial disc 1
Put on.

Alternatively, the artificial intervertebral disc 1 may be attached to a portion where the intervertebral disc E is removed, for example, between the vertebral bodies C ₄ and C ₅ as shown in FIG.

In this case, a plurality of protrusions 2 are formed below the artificial intervertebral disc 1 and can be stably placed on the facing vertebral body C ₅ without moving. Further, since the saddle-shaped curved surface 5 having a groove is formed on the upper surface of the artificial intervertebral disc 1, the vertebral body C ₄ can be moved in the anteroposterior direction as guided by the circular groove 5.

The artificial intervertebral disc 1 of the present invention is made of the above-mentioned ceramic material such as alumina or apatite, or a metal material such as titanium or tantalum, or a surface-treated material having biocompatibility on the surface of the metal material. It may be one.

Further, the size of the artificial intervertebral disc 1 varies depending on the size of the vertebral body or skeleton to be applied, and may be appropriately selected according to the size and shape thereof, or the vertebral body to be mounted may have a predetermined size. It can also be fitted by cutting.

By the way, according to the average clinical results using the artificial intervertebral disc of the present invention as described above, it is possible to sit up after 3 days with a simple cervical brace attached after surgery, and to stand up and walk in 1 week. It was possible.

〔The invention's effect〕

As described above, according to the present invention, it is possible to bring about a reliable therapeutic effect while preserving the cervical spine mobility, to ensure a normal intervertebral space semipermanently, and to ensure the normal mobility of the cervical spine motor unit. It is extremely beneficial to the social welfare of humankind, such as being able to secure it.

[Brief description of drawings]

FIG. 1 shows an artificial intervertebral disc according to the present invention, wherein (a) is a front view, (b) is a cross-sectional view taken along line YY in (a),
(C) The figure is a bottom view. FIG. 2 is a front view showing a state in which the artificial intervertebral disc of the present invention is mounted between the cervical vertebrae, and FIG. 3 is a side view of a cervical vertebra for explaining an application example in which the artificial intervertebral disc of the present invention is mounted. 1 ... Artificial intervertebral disc, 2 ... Protrusion 5 ... Saddle-shaped curved surface

Claims (1)

[Claims] 1. A material having biocompatibility such as ceramic, biocompatibility, mechanical strength, corrosion resistance, etc.,
An artificial intervertebral disc for cervical spine, which has a saddle-shaped curved surface on its upper surface and has a plurality of projections on its lower surface.