KR100426012B1 - fusion cage - Google Patents

Abstract

PURPOSE: The present invention aims to provide a fusion cage that facilitates fusion of the lumbar spine and maintains the normal lumbar spine curve of patients with lumbar disc disease, thereby reducing the patient's feeling of turbulence.

Composition: The fusion cage is the upper body (1), the lower body (3) provided on the opposite side of the upper body, the connecting member (5) for pivotally connecting the upper body and one side of the lower body with a pin, and One side of the connecting member is screwed forward and backward as the other side is composed of a support (7) to open the opposite end of the connecting member of the upper body and the lower body.

Effect: This fusion cage is folded when the upper body and the lower body are inserted between the vertebrae and spreads out after insertion, thereby being less disturbed by the incision when inserted into the incision for fusion of the lumbar spine. Even small incisions allow insertion of the lumbar spinal fusion without damaging nerves, blood vessels or other lethal structures, while also maintaining the normal curve of the lumbar spine, reducing patient discomfort. .

Description

Fusion cage

The present invention relates to a spinal fusion mechanism, and more particularly, to a fusion cage for fusion of the lumbar vertebral body.

The fusion cage provides an insertion space for fusion between the vertebrae and the vertebrae. The vertebrae and the vertebrae merge into one another, through which the bone, which is implanted through or around the fusion cage, grows into a reticular structure.

Currently used fusion cages are variously treated for spinal disorders. The fusion cage is inserted into the intervertebral disc space between the two bodies to bring the bodies together. The fusion cage extends into the collapsed disk space between the two vertebrae to stabilize the vertebrae.

Typical fusion cages are cylindrical, hollow and screwed. Other fusion cages may be threadless, tapered, elliptical, or rectangular in shape. These fusion cages are formed from various materials such as titanium alloys, porous tantalum, and other metals, tagged bones, or ceramics.

Fusion cages may be used to connect adjacent portions of the vertebrae, but primarily for the connection of the lumbar vertebrae. Fusion cages may also be used for cervical or chest vertebrae.

Fusion cages can be used for insertion in anterior, posterior, and lateral lumbar fusion. This insertion is usually made through an incision in the lumbar region, and other implants may be used.

Screwed fusion cages use wedges or other instruments on one side of the spine to open the disk space between the two vertebrae of the lumbar spine, drill a hole, and insert it into the hole. The tapered plug is embedded with the disk space open.

There is a problem with the approach for insertion of the fusion cage. In posterior lumbar fusion, the neural structure of the spinal cord and small holes requires proper retraction before the plug is lodged between the disc intervertebral discs.

The retracting of the nerve structure during the insertion of the fusion cage is crucial. Inappropriate retracting of this neural structure implies a possible nerve paralysis of the lower extremities due to severe nerve damage during insertion.

In posterior or lateral approach, blood vessels or other lethal structures need to be retracted and protected to reduce or prevent bleeding.

The fusion cage needs to correspond appropriately to the difference in distance between the anterior and posterior side in order to maintain the normal spine curve formed between the vertebra and the vertebra in the lumbar spine fusion bent from the anterior to the posterior. Here, the anterior side and the posterior side mean the abdominal direction with respect to the back and the back direction with respect to the abdomen, respectively.

The present invention is to meet the needs as described above, when inserted into the incision for fusion of the lumbar spine, less interrupted by the incision, it is possible to insert into a smaller incision, neural structure, vascular structure or It eliminates the need for other critical retracts, while providing a wider coalescing area than other cages of the same size, as well as maintaining the normal lumbar curve in response to the difference in distance between the anterior and posterior sides formed between the vertebrae. The purpose is to provide a fusion cage that can reduce the patient's feeling of discomfort.

The fusion cage that realizes this includes: an upper body, a lower body provided on an opposite side of the upper body, a connecting member for pivotally connecting the upper body and one side of the lower body, and one side of which is screwed to the connecting member. It is configured to include a support for opening the opposite side of the connecting member of the upper body and the lower body as the other side forward and backward coupled.

Here, the upper body and the lower body to engage the engaging portion provided on the opposite end of the connecting member, thereby limiting the range in which the upper body and the lower body spread.

The upper body and the lower body are formed into curves having a constant radius of curvature so as to resemble the transverse curves of the respective bodies when inserted between the bodies. The upper body and the lower body are formed in pairs of left and right symmetry having a constant curve so as to be similar to the transverse curve of the vertebral body.

In addition, the upper body and the lower body have opposite inclined surfaces each having a shape spaced apart from each other toward the connecting member side on the opposite inner surface thereof. This opposite slope is provided with one side of the support, which is shaped like a hemispherical shape, allowing the upper and lower bodies to naturally 'open and fold' as they move forward and backward.

1 is a plan view of a fusion cage according to the present invention;

FIG. 2 is a cross-sectional view of the fusion cage in a folded state along line A-A in FIG. 1; FIG.

3 is a cross-sectional view taken along the line B-B of FIG.

4 is a perspective view of another embodiment of the support;

5 is a cross-sectional view of an open state of a fusion cage taken along the line A-A of FIG.

6 is a cross-sectional view of a state in which the fusion cage is inserted by folding between the vertebral bodies;

Figure 7 is a cross-sectional view of the state opened by inserting the fusion cage between the vertebral body.

8 is a plan view of a state in which a fusion cage is inserted between vertebral bodies;

9 is another plan view of the fusion cage inserted between the vertebral bodies;

10 is a perspective view of a second embodiment of the fusion cage according to the present invention.

FIG. 11 is a front view of FIG. 10; FIG.

12 is a plan view of FIG. 10.

Figure 13 is a perspective view of a third embodiment of the fusion cage according to the present invention.

14 is a front view of FIG. 13;

FIG. 15 is a cross-sectional view of the fusion cage of FIG. 13 inserted between vertebral bodies; FIG.

* Description of the symbols for the main parts of the drawings *

1: upper body 3: lower body

5: connecting member 7: support

17,19: engaging portion 21,23: opposite slope

27: hemisphere shape

Advantages and advantages of the present invention will be more apparent from the following detailed description based on the accompanying drawings.

1 is a plan view of a fusion cage according to the present invention, Figure 2 is a cross-sectional view taken along the line AA of Figure 1, Figure 3 is a cross-sectional view taken along the line BB of Figure 2, the upper body 1, the lower body 3 The connection member 5 and the support 7 constitute a fusion cage FC for lumbar fusion.

The upper body 1 and the lower body 3 are the most important parts of the fusion cage FC, which are formed and provided in opposing postures. The hole 9 is provided so as to fuse the vertebral body while growing and penetrating or surrounding the fusion cage FC.

In addition, the surface of the upper body (1) and the lower body (3) is formed with an unevenness (11) for improving the union with the vertebrae, the sides of the combined upper body (1) and the lower body (3) is open It keeps being in a state.

The upper body 1 and the lower body 3 are coupled to each other so that one side thereof can be pivoted to the connecting member 5 by the pins 13. Accordingly, the ends of the upper body 1 and the lower body 3 opposite to the connecting member 5 form a structure that can be 'opened and folded' to face each other.

At this time, the upper body 1 and the lower body 3 so that the upper body 1 and the lower body 3 on the opposite side of the connecting member 5 so as to be opened only within a predetermined range, each engaging portion 17 19).

The locking portions 17 and 19 have an upper body 1 and a lower body 3 on the locking portions 17 and 19 side when the fusion cage FC is inserted and opened between the vertebrae and the front side between the vertebral bodies. Position so that the fusion cage FC can properly support between the lumbar vertebrae. In other words, in the lumbar vertebrae, the front side is far from each other and the rear side maintains a close distance to each other.

In addition, the upper body 1 and the lower body 3 are formed in a curve having a constant radius of curvature R as shown in the plan view of FIG. 1. This curve increases the union area when the fusion cage FC is inserted between the vertebral bodies as compared to the straight line, and is formed similarly to the lateral curve of each vertebral body. Accordingly, the upper body 1 and the lower body 3 are formed in pairs in consideration of being inserted into the left and right sides of the vertebral body in consideration of the fact that the vertebral body has a constant curve on a plane. That is, the left upper body 1 and the lower body 3 are formed in the right upper body 1 and the lower body 3 in symmetrical directions, respectively. Here, the left side and the right side mean the left side and the right side when looking at the abdomen side from the back side.

The upper body 1 and the lower body 3 are provided with opposing inclined surfaces 21 and 23 on the external appearance and the opposite inner surface thereof, respectively. The opposing inclined surfaces 21 and 23 are formed such that the distance from each other gradually increases toward the connecting member 5 from the engaging portions 17 and 19. Accordingly, the opposing inclined surfaces 21 and 23 allow mutual adjustment of the separation distance between the upper body 1 and the lower body 3 when one side of the support 7 is inserted therebetween.

One side of the support 7 is screwed to the connecting member 5, and constitutes a trench groove 25 so that the support member 7 can move forward and backward on the connecting member 5. The other side of the support 7 is formed in a hemispherical shape 27.

One side of the support (7) of the hemispherical shape (27) is located on the opposite inclined surfaces (21, 23) of the upper body (1) and the lower body (3), the upper body (1) and the lower body in accordance with the forward and backward (3) can open the opposite side of the connecting member (5). At this time, the hemispherical shape 27 is a shape that allows the upper body 1 and the lower body 3 to be operated by natural contact with the opposing inclined surfaces 21 and 23, and the vector component force with respect to the advancing direction of the support 7. If the shape can generate a conical shape, conical column shape and the like can also be applied.

The hemispherical shape 27 is also responsible for pushing the implanted bone from the right side to the left side (in Fig. 5) to push it out of the fusion cage FC through the hole 9. Of course, the implanted bone (not shown) is located in the space (s) between the hemispherical shape 27 and the locking portion (17, 19). This space s enables insertion of a bone graft (not shown) into the interior of the fusion cage FC.

In addition, the support 7 of the trapezoid shape 27a is illustrated in FIG. That is, since the trapezoidal shape 27a in contact with the opposite inclined surfaces 21 and 23 of the upper body 1 and the lower body 3 is the same as the effect of the hemispherical shape 27, description thereof will be omitted. However, the hemispherical shape 27 is formed integrally with the support 7, whereas the trapezoidal shape 27a is connected to the support 7 and the ball joint 7a.

As shown in FIG. 5, the fusion cage configured as described above opens one end of the upper body 1 and the lower body 3 as shown in FIG. 5.

In more detail, when a wrench (not shown) is inserted into the trench groove 25 and rotated in the direction of the arrow a, the support 7 moves toward the engaging portions 17 and 19 (b).

Accordingly, the opposing inclined surfaces 21 and 23 located at one end of the hemispherical shape 27 of the support 7 receive a vector component force, and the upper body 1 and the lower body 3 are opened to each other (c). At this time, the separation distance between the upper body 1 and the lower body 3 is limited to a predetermined range by the locking parts 17 and 19.

Then, when a wrench (not shown) is inserted into the trench groove 25 and rotated in the direction of the arrow d, the support 7 proceeds in a direction away from the locking portions 17 and 19 (e).

Accordingly, the upper body 1 and the lower body 3 are folded (f) while the vector component force acting on the opposite inclined surfaces 21 and 23 is removed by the hemispherical shape 27 of one end of the support 7 (f). At this time, the vector component acting on the locking parts 17 and 19 is removed.

Fusion cage FC 'opened and folded' as described above is inserted between the vertebral body 29 and the adjacent vertebral body 31 perforated by the lumbar fusion instrument as shown in FIG. 6. Since various things can be applied to the fusion mechanism for drilling between the vertebral body 29 and the vertebral body 31, description thereof will be omitted.

At this time, the fusion cage FC is inserted with the upper body 1 and the lower body 3 folded.

Therefore, it is inserted smoothly without causing interference with neural tissue and the like exposed to portions cut around the vertebrae 29 and 31 forming the lumbar vertebrae. This in turn necessitates the retraction of neural tissue.

When the support 7 is operated in this state, as shown in Fig. 7, the engaging portions 17 and 19 of the upper body 1 and the lower body 3 are opened. As such, the gap between the upper body 1 and the lower body 3 is already mentioned in FIG. 5 and thus is omitted here. Therefore, the outer surfaces of the upper body 1 and the lower body 3 are in close contact with the support body 29 and the support body 31.

The upper body 1 and the lower body 3 thus opened overcome the difference in curvature formed by the front side g and the rear side h of the lumbar spine. That is, although the distance between the vertebrae 29 and the vertebrae 31 is formed farther from the front side g than the rear side h, the vertebrae 29 and the vertebral body 31 are interposed between the fusion cage FC. Supported in a stable state.

In addition, the fusion cage FC inserted between the vertebrae 29 and the vertebral body 31 through the processes of FIGS. 6 and 7 is left and right on the vertebral body 31 as shown in FIG. Are arranged in pairs.

At this time, the upper body 1 and the lower body 3 of each fusion cage FC are inserted and supported in a curved shape similar to the curve i on the plane of the vertebral body 31. In other words, the left fusion cage FC forms the symmetrical shape of the left curve i and the right fusion cage FC of the vertebrae 31, like the right curve of the vertebrae 31, thereby making the vertebrae 29 and 31 more stable. I support it.

FIG. 9 illustrates another embodiment in which the fusion cage FC may be inserted. The pair of fusion cages FC is inserted and supported in the plane of the vertebrae 31 in the opposite direction to that of FIG. 8.

FIG. 10 is a perspective view of a second embodiment of a fusion cage FCa according to the present invention, FIG. 11 is a front view of FIG. 10, and FIG. 12 is a plan view of FIG. 10. The description will be omitted, and only the other parts will be described in comparison with the above embodiment.

First, the embodiment is inserted into the vertebral body 31 in a folded state, and configured to open in the vertebral body 31, but when the second embodiment is inserted into the vertebral body 31, the normal spinal vertebral bone is normal. It is configured to maintain the curve.

That is, in this fusion cage FCa, the front part 33 is formed higher than the rear part 35, and the upper and lower surfaces of the fusion cage FCa are inclined by a predetermined angle j. It has a shape that converges from the front portion 33 toward the rear portion 35. This angle (j) may be variously formed according to the body of the patient, but usually 4 to 8 degrees is preferred.

In the above embodiment, the holes 9 are formed only in the up and down direction (in Fig. 4) of the fusion cage FC. In the second embodiment, the holes 9 and 9a are arranged in the up and down and front and rear directions (in Fig. 10). Formed. Therefore, the implanted bone (not shown) is configured to protrude in the vertical and front directions (in FIG. 10) of the fusion cage FCa.

FIG. 13 is a perspective view of a third embodiment of a fusion cage according to the present invention, and FIG. 14 is a front view of FIG. 13, and the overall configuration thereof is similar to that of the second embodiment, and thus, the overall description thereof is omitted and only the second embodiment is omitted. Explain while comparing with an example.

While the fusion cage FCa of the second embodiment is formed to be inclined at a constant angle j with its upper and lower surfaces flat, the fusion cage FCb of the third embodiment has a difference in which the upper and lower surfaces are convex. have. In addition, the inner circumferential surface of the hole 9a of the second embodiment is formed up and down (in Fig. 11) in parallel, whereas the inner circumferential surface of the hole 9b of the third embodiment is vertically up (in Fig. 14) (Fig. 14). Is convex.

As shown in FIG. 15, the fusion cage FCb formed convexly in the vertical direction is formed in a concave shape in the lumbar spine so that it does not fall out between the vertebrae 29 and 31. The vertebrae 29 and 31 allow for better union.

Like the fusion cages FC of the second and third embodiments, the fusion cages FCa and FCb are inserted into the vertebral bodies 29 and 31 as shown in FIGS. 8 and 9.

As such, the fusion cage of the present invention is formed to be 'opened and folded' by connecting the upper body and the lower body with a connecting member, so that the upper body and the lower body are folded with each other during insertion, and the upper body and the lower body are inserted between the vertebral bodies. By opening the lower body, it is less obstructed by the incision when inserted into the incision for fusion of the lumbar vertebrae, allowing insertion into even smaller incisions, retracting nerves, blood vessels or other lethal structures. In this case, the patient's uncomfortable feeling can be reduced by appropriately coping with the distance difference between the front side and the rear side formed between the vertebrae.

In addition, since the fusion cage of the present invention is formed in a curved shape unlike the straight fusion cage that has been released to date, it is possible to considerably increase the area between the vertebrae to be fused up and down than other fusion cages of the same size.

Existing fusion cages were all operated at the anterior or posterior end, but did not provide a space for implanting the spongy bone required for bone union, but the fusion cage of the present invention can insert the graft bone inside the cage, and In addition, a large amount of bone can be placed in the vicinity of the fusion to maximize the surgical effect.

Claims (8)

Upper Body (1), A lower body 3 provided on an opposite side of the upper body, A connecting member 5 connecting the upper body and one side of the lower body with a pin so as to be pivotable; and One side of the connection member is screwed to the connection member forward and backward as the other side of the fusion cage including a support (7) to open the opposite end of the connection member of the upper body and the lower body. 2. The fusion cage according to claim 1, wherein the upper body (1) and the lower body (3) comprise catching portions (17, 19) provided to be connected to opposite ends of the connecting member. The method of claim 1, wherein the upper body (1) and the lower body (3) is formed as a curve having a constant radius of curvature (R) so as to resemble the transverse curve (i) of each vertebra when inserted between the vertebral bodies. The fusion cage characterized by the above. The fusion cage according to claim 1, wherein the upper body (1) and the lower body (3) are each formed symmetrically with a constant curvature so as to be similar to the transverse curve of the vertebral body. 2. The fusion cage according to claim 1, wherein the upper body (1) and the lower body (3) include opposite inclined surfaces (21, 23) formed on the opposite inner surface of the upper body (1) toward the connecting member. The fusion cage according to claim 1, wherein the support (7) is formed in a hemispherical shape (27) on one side of the upper body and the opposite inclined surface formed on the inner side of the lower body of the lower body. The anterior part when inserted between the vertebrae is formed higher than the rear part, and the upper and lower surfaces are formed in a plane having a constant angle so as to converge from the front part to the rear part, and the hole from which the bone graft grows is the upper and lower directions And a further hole is formed in the front-rear direction at the center of the height direction of the hole. 8. The fusion cage according to claim 7, wherein the upper and lower surfaces are formed at the same height as the front part and the rear part, and are formed convexly in the upper and lower directions when the middle part is inserted between the vertebral bodies.