JP2010051651A - Intervertebral spacer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intervertebral spacer which increases the fixation strength with an intervertebral body to prevent it from deviating from the right position. <P>SOLUTION: The intervertebral spacer 1 includes a cylindrical cage 2 and a blade 3, wherein the cylindrical cage 2 holds an artificial bone or an autoplastic bone B and is inserted into a disk space A to be sandwiched toward the thickness direction; and the blade 3 is rotatably supported around a rotation axis 2a line along the insertion direction in the outer surface positioned backside of the insertion direction of the cage 2, and has a short axis 3a which has a length of equal to or less than the length in the thickness direction of the outer surface, and a long axis 3b which crosses the short axis 3a and is longer than the length, and further is made to gnaw into an intervertebral body C sandwiching the cage 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an intervertebral spacer.

  As a treatment method for spinal cord diseases such as cervical spondylosis and intervertebral disc herniation that develops when the spinal cord is compressed, the intervertebral disc is removed at the location where compression is applied, the spinal cord is decompressed, and a spacer is inserted between the vertebrae from which the intervertebral disc has been removed Thus, a method of fixing the upper and lower vertebral bodies is used. As a spacer used in this case, an intervertebral spacer that inserts a cage containing an S-shaped blade between the vertebrae, rotates the blade 90 degrees, and bites part of the blade into the upper and lower vertebral bodies to fix it. Is known (for example, see Patent Document 1). Further, there is known a columnar spacer in which a spiral groove is carved on a side surface, and is inserted and fixed between vertebrae in the manner of a screw (for example, see Non-Patent Document 1).

US Pat. No. 6,777,0096 Titanium cage for anterior cervical fixation, product information, [online], Amtec Co., Ltd. [Search August 5, 2008], Internet <URL: http://www.ammtec.co.jp/seihin/m- cage.html>

  However, in the case of Patent Document 1, since the S-shaped blade tends to be wide, the cage becomes large and insertion is difficult, or the length direction of the blade is limited by the size of the cage. There is a problem that it cannot be secured and the fixing force cannot be increased. In addition, in the case of Non-Patent Document 1, there is a problem that the position of the spacer gradually shifts in the depth direction due to the movement of the spine after the operation, and is depressed.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide an intervertebral spacer that can enhance a fixing force with a vertebral body and prevent a positional shift in advance.

In order to achieve the above object, the present invention provides the following means.
The present invention includes a cylindrical cage that accommodates an artificial bone or autologous bone inside and is sandwiched in the thickness direction and inserted between the vertebrae, and an outer surface located on the rear side in the insertion direction of the cage in the insertion direction. A short axis that is not more than a length in the thickness direction of the outer surface and a long axis that is orthogonal to the short axis and that is longer than the length, and sandwiches the cage An intervertebral spacer comprising a blade for biting into vertebral bones is provided.

  According to the present invention, the short axis of the blade is placed along the thickness direction of the cage, and the intervertebral spacer is inserted between the vertebrae while expanding the gap between adjacent vertebral bodies. When the blade is rotated, both ends in the minor axis direction of the blade protrude from the end face of the cage, and the end of the blade bites into the end plate of the adjacent vertebral body, thereby fixing the intervertebral spacer in the insertion direction. Can do.

  In this case, since the blade is disposed outside the cage, the dimension in the longitudinal direction of the blade can be increased without being limited by the dimension of the cage. As a result, the length of the blade in the long axis direction can be sufficiently secured to increase the amount of biting into the vertebral body, and the fixation force in the insertion direction of the intervertebral spacer with the vertebral body can be enhanced. The displacement of the position of the subsequent intervertebral spacer can be prevented.

  It is also possible to fill the entire cage with autologous bone or artificial bone and increase the amount of these inserted between the vertebrae. In addition, since the contact area between the autologous bone or artificial bone in the cage and the vertebral body is ensured, it is possible to accelerate the bone fusion.

  In the above invention, the blade has the same rotation axis as the blade, and one end surface of the opposite side of the cage includes a columnar portion fixed to the blade, and a protrusion extending in the circumferential direction on the outer peripheral surface of the columnar portion. It may be provided.

If the blade bites into the vertebral body at a position where the depth of the intervertebral depth is shallow, the strength of the vertebral body may be reduced. According to the present invention, the columnar portion is disposed behind the blade in the insertion direction, and the intervertebral spacer is arranged. By inserting the whole between the vertebrae, the blade can be easily and reliably inserted to an appropriate depth.
Further, by providing a protrusion on the outer peripheral surface of the columnar part, when the columnar part is rotated, the protrusion bites into the end plate of the vertebral body in the rotation direction, and the fixing force in the insertion direction of the intervertebral spacer can be further enhanced. .

In the above invention, a rotation stop member may be provided which is fixed to the cage or the blade while being inserted between the vertebrae and rotating the blade to fix the rotation of the blade.
By doing so, it is possible to prevent a decrease in fixing force and a shift in the position of the intervertebral spacer due to the rotation of the blade after the operation.

  According to the present invention, there is an effect that it is possible to enhance the fixing force with the autologous bone and prevent the displacement of the position.

An intervertebral spacer 1 according to an embodiment of the present invention will be described below with reference to FIGS. 1 and 2.
As shown in FIG. 1, the intervertebral spacer 1 according to this embodiment includes an intervertebral spacer main body 5 including a cage 2, a blade 3, and a columnar portion 4 in order from the front side to the rear side in the insertion direction of the intervertebral A. And a rotation stop member 6 for fixing the rotation of the blade 3 after the spacer body 5 is inserted into the intervertebral space A.

The cage 2 has a cylindrical shape, and is made of, for example, metal or resin. An autogenous bone collected from a human body or an artificial bone mainly composed of calcium phosphate is filled into the cage 2 as a grafted bone B.
The blade 3 has a short axis 3 a and a long axis 3 b that are orthogonal to each other. The short axis 3 a has a length equal to or less than the dimension in the thickness direction of the cage 2, and the long axis 3 b is smaller than the dimension in the thickness direction of the cage 2. Is also getting longer.

  One end face of the columnar portion 4 is fixed near the center of the blade 3, and the other end face is provided with a key hole 7 and a screw hole 8 deeper than the key hole 7 at the center of the key hole 7. Similarly to the blade 3, the columnar portion 4 also has a minor axis that is not more than the dimension in the thickness direction of the cage 2 and a major axis that is longer than the dimension, and the minor axes of the blade 3 and the columnar section 4 are the same. It is arranged along the direction. In addition, a protrusion 4 a extending in the circumferential direction is provided on the outer peripheral surface of the columnar portion 4 in the minor axis direction.

The blade 3 and the columnar part 4 are supported so as to be rotatable around an axis (rotating axis) 2a fixed perpendicularly to an outer surface located rearward in the insertion direction of the cage 2.
When the intervertebral spacer main body 5 is inserted into the intervertebral A, the blade 3 and the short axis 3a of the columnar portion 4 are arranged in the direction along the thickness direction of the cage 2, and the blade 3 and the The columnar portion 4 is accommodated.

  As shown in FIG. 2, when a tool 9 having the same shape as the keyhole 7 at the tip is inserted into the keyhole 7 and rotated about the axis in the insertion direction, the columnar portion 4 and the blade 3 are integrated with the shaft 2a. The side surfaces of the blade 3 and the columnar part 4 in the direction of the minor axis 3a protrude from both end surfaces of the cage 2.

  The anti-rotation member 6 is provided with a groove 6a in the thickness direction having a width substantially the same as the length in the minor axis 3a direction of the blade 3 on the side surface of the rectangular parallelepiped block having the thickness dimension substantially the same as that of the cage 2. Thus, the columnar portion 4 is fitted in the groove 6a. Further, a through hole 6b is provided in the bottom surface of the groove 6a, and the columnar part 4 is fitted into the groove 6a of the rotation preventing member 6 in a state where the blade 3 and the columnar part 4 are rotated in the intervertebral space A. When the screw 8a is inserted into the screw hole 8 and tightened, the rotation of the blade 3 is fixed.

The operation of the intervertebral spacer 1 configured as described above will be described below with reference to FIGS. 3 and 4.
In order to fix the intervertebral spacer 1 according to the present embodiment to the intervertebral A, the cage 2 in which the adjacent vertebral body C of the intervertebral A from which the intervertebral disc has been removed is expanded and the transplanted bone B is filled therein is formed. The intervertebral spacer body 5 is inserted in the direction of being sandwiched between the end plates D of the vertebral body C in the thickness direction.

  Then, when the tool 9 is inserted into the key hole 7 and the columnar part 4 and the blade 3 are rotated, as shown in FIG. 3, the blade 3 and the protrusion 4a of the columnar part 4 are bitten into the end plate D, The spacer body 5 is fixed in the insertion direction. Subsequently, as shown in FIG. 4, when the rotation preventing member 6 is arranged so that the columnar portion 4 fits into the groove 6a, the screw 8a is inserted into the screw hole 8 from the through hole 6b and the screw 8a is tightened, the spine The interspacer 1 can be fixed to the intervertebral A.

  Thus, according to the present embodiment, the blade 3 is arranged outside the cage 2. As a result, the length of the blade 3 in the major axis 3b direction is not limited to the inner dimension of the cage 2, so that the length of the blade 3 in the major axis 3b direction is sufficiently secured and a position deep from the end plate D of the vertebral body C. There is an advantage that the fixing force between the intervertebral spacer main body 5 and the vertebral body C can be increased by encroaching the blade 3 to increase the amount of biting.

  Further, since the transplanted bone B can be filled in the entire cage 2, a sufficient space for the transplanted bone B is secured, and the amount of the transplanted bone B inserted into the intervertebral A can be increased. Furthermore, since a large contact area between the filled bone B filled in the cage 2 and the vertebral body C is ensured, the bone fusion of the grafted bone B can be accelerated.

  Further, by providing the columnar portion 4 on the rear side in the insertion direction of the blade 3, when the entire intervertebral spacer main body 5 is inserted into the intervertebra A, the blade 3 is inserted to an appropriate depth. Accordingly, the blade 3 can be bitten in an appropriate insertion direction position of the vertebral body C without the blade 3 biting into the vicinity of the end face of the vertebral body C and reducing the strength of the vertebral body C.

  Further, in the case of the intervertebral spacer having only the columnar portion 4, there is an inconvenience that the intervertebral spacer 1 according to the present embodiment gradually shifts in the insertion direction. Further, by fixing the rotation of the blade 3 by the anti-rotation member 6, it is possible to prevent the displacement of the intervertebral spacer 1 after the operation and the reduction of the fixing force.

In the above embodiment, the shape of the blade 3 is a flat plate shape. Instead, for example, an S-shape as shown in FIG. 5 or a curve curved in the insertion direction as shown in FIG. Plate shape may be sufficient.
In this way, the intervertebral spacer 1 can be fixed to the vertebral body C in the direction in which the vertebral body C is separated.

Moreover, in the said embodiment, a space may be provided inside the columnar part 4, and this space may be filled with the transplanted bone.
In this way, bone fusion can be achieved even in front of the intervertebral A.

It is a top view which shows the intervertebral spacer which concerns on one Embodiment of this invention. It is a figure which shows operation | movement of the braid | blade of the intervertebral spacer of FIG. 1, a columnar part, and a rotation stop member. It is a figure which shows the state which fixed the intervertebral spacer main body of FIG. 1 with the vertebral body. It is a figure which shows the operation | movement which fixes an anti-rotation member to the intervertebral spacer main body fixed to the vertebral body. It is a figure which shows the modification of the braid | blade of the intervertebral spacer of FIG. It is a figure which shows the modification of the braid | blade of the intervertebral spacer of FIG.

Explanation of symbols

1 Intervertebral spacer 2 Cage 2a axis (rotating axis)
DESCRIPTION OF SYMBOLS 3 Blade 3a Short axis 3b Long axis 4 Columnar part 4a Protrusion 5 Intervertebral spacer main body 6 Anti-rotation member 6a Groove 6b Through hole 7 Key hole 8 Screw hole 8a Screw 9 Tool A Intervertebral B Transplanted bone (artificial bone or autogenous bone)
C Vertebral body D Endplate

Claims (3)

A cylindrical cage that contains artificial bone or autologous bone inside and is sandwiched between the vertebrae in the thickness direction,
The outer surface located on the rear side in the insertion direction of the cage is supported so as to be rotatable about the rotation axis along the insertion direction, and the minor axis is equal to or less than the length of the outer surface in the thickness direction, and is orthogonal to the minor axis. An intervertebral spacer comprising a long axis longer than the length and a blade that bites a vertebral body sandwiching the cage.   The rotating shaft is the same as that of the blade, and one end surface of the opposite side of the cage is provided with a columnar portion fixed to the blade, and a protrusion extending in the circumferential direction is provided on the outer peripheral surface of the columnar portion. Item 4. The intervertebral spacer according to Item 1.   The intervertebral spacer according to claim 1 or 2, further comprising an anti-rotation member that is inserted between the vertebrae and fixed to the cage or blade in a state where the blade is rotated, and fixes rotation of the blade.

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