JP2009195313A - Intervertebral spacer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intervertebral spacer capable of sufficiently absorbing loads and impact applied to the intervertebral region, having mechanical strength strong enough to suppress damage or chipping. <P>SOLUTION: The intervertebral spacer is made of metal to be inserted into and disposed in the intervertebral region. A single or a plurality of spaces are formed within the wall thickness in the direction of thickness, and the elasticity is applied by the spaces to loads on the intervertebral region. Preferably, the space is at least either a hollow part formed from one surface to the other surface to be opened on both surfaces, or a recessed slit formed on either surface. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an intervertebral spacer.

In the vertebrae constituting the cervical vertebra and the lumbar vertebra, a predetermined interval is provided to each vertebra by an intervertebral disc.
Therefore, for example, when a problem occurs in the intervertebral disc, the interval between the vertebrae may not be maintained in a normal state.
Conventionally, in order to correct a narrowed intervertebral space to a normal state, it has been practiced to correct the narrowed intervertebral space using an artificial intervertebral spacer such as an artificial intervertebral disc.

Japanese Patent Laid-Open No. 8-10275 discloses a screw-type intervertebral spacer (see Patent Document 1).
Japanese Laid-Open Patent Publication No. 9-122160 discloses an artificial intervertebral spacer having a substantially arc shape in plan view and having fixing spikes 5 formed on upper and lower surfaces (see Patent Document 2).
Japanese Patent Laid-Open No. 2002-956885 discloses an artificial intervertebral spacer in which protrusions are provided on both upper and lower surfaces, and the thickness is increased on the insertion distal end side (see Patent Document 3).
Japanese Patent Application Laid-Open No. 2004-73547 discloses an intervertebral spacer in which both upper and lower surfaces are formed into a curved surface having an apex in the middle in the front-rear direction, and a plurality of nail-shaped claw-shaped portions are provided on the upper and lower surfaces. (See Patent Document 4).
On the other hand, Japanese Patent Laid-Open No. 10-248861 discloses a fusion implant having a body portion that can contract and expand around a longitudinal axis (see Patent Document 5).
Japanese Patent Application Laid-Open No. 2005-287611 discloses a cylindrical spacer in which an elastic body is provided between a pair of hard members, the outer periphery of which is configured as a screw (see Patent Document 6). .
JP-A-8-10275 JP-A-9-122160 Japanese Patent Laid-Open No. 2002-956885 JP 2004-73547 A Japanese Patent Laid-Open No. 10-248861 JP 2005-287611 A

The intervertebral spacers shown in Patent Documents 1 to 4 are inserted and arranged between vertebrae and can secure a gap between vertebrae. However, they are hard and apply a load applied between upper and lower vertebrae. There was a problem that it could not be absorbed by the spacer. For this reason, when these intervertebral spacers are used, there is a concern that a new problem is caused in a portion adjacent to the intervertebral spacer.
In the case of the fusion implant shown in Patent Document 5, the load applied between the upper and lower vertebrae cannot be sufficiently absorbed although it can contract and expand around the longitudinal axis. .
In addition, in the case of the spacer described in Patent Document 6, although the load applied between the upper and lower vertebrae can be absorbed well, partial damage from the material aspect, and the overall strength surface There are also problems.

  Accordingly, the present invention provides an intervertebral spacer that solves the above-mentioned problems of the prior art, can sufficiently absorb the load and impact applied between the vertebrae, and has good mechanical strength and is less likely to be damaged or chipped. Is an issue.

  In order to achieve the above object, the intervertebral spacer of the present invention is a metal intervertebral spacer that is inserted and disposed between the vertebrae, and one or a plurality of voids are formed in the thickness in the thickness direction. The first feature is that elasticity is applied to the load applied between the vertebrae by the gap.

  In the intervertebral spacer of the present invention, the gap is at least one of a hollow portion of a double-sided opening formed from one surface to the other surface, and a concave slit portion formed on either surface. It is preferable. As the gap portion, a hollow portion having a double-sided opening formed from the distal end surface to the proximal end surface in the insertion direction, a concave slit portion formed in the distal end surface or the proximal end surface in the insertion direction, and the left-right direction perpendicular to the insertion direction It is most suitable that it is at least one kind of gap portion selected from concave slit portions formed on any one of the side surfaces.

  In addition to the first feature, the intervertebral spacer of the present invention includes an upper surface in contact with the upper vertebra, a lower surface in contact with the lower vertebra, a distal end surface and a proximal end surface in the insertion direction, an upper vertebra and a lower vertebra. The second feature is that it has a substantially rectangular parallelepiped shape including left and right lateral surfaces located between vertebrae.

  As this intervertebral spacer, a horizontal hollow portion having a shape penetrating from the distal end surface to the proximal end surface is formed at a position located at a substantially central position in the thickness direction, and approximately in the middle between the horizontal hollow portion and the upper surface. A horizontal slit portion having a certain depth is formed from each of the left and right side surfaces from the front end surface to the base end surface, respectively, at the position that is positioned and at a position that is positioned approximately in the middle between the horizontal hollow portion and the lower surface. Is preferred. The horizontal hollow portion preferably has a flat cross-sectional shape, and the end portions on the left and right side surfaces of the horizontal hollow portion are from the bottoms of the horizontal slit portions formed on the left and right side surfaces, respectively. It is preferable to be located on the left and right side surfaces.

  In addition to the first feature, the intervertebral spacer of the present invention may have a substantially cylindrical shape in which a screw for screwing is formed on the side periphery. Specifically, in addition to the first feature, the intervertebral spacer of the present invention has a substantially cylindrical shape in which a screw for screwing is formed on the side periphery, and the distal end surface and the proximal end surface in the insertion direction A horizontal slit portion having a constant depth is formed at a portion located in the approximate center on one of the end surfaces, and a portion located at the approximate center where the horizontal slit portion is formed on the other end surface and the upper end. A horizontal slit portion having a fixed depth is formed in a portion corresponding to a substantially middle position, a portion located substantially in the middle of the horizontal slit portion where the horizontal slit portion is formed, and a portion corresponding to a substantially middle position between the lower ends. This is a third feature.

  As this intervertebral spacer, the bottom of the concave portion of the horizontal slit portion formed on one surface of the distal end surface and the base end surface is on the other surface side than the bottom of the concave portion of the horizontal slit portion formed on the other surface. It is preferable that it is located in.

  In addition to the first feature, the intervertebral spacer of the present invention has a substantially columnar shape in which a screw for screwing is formed on the side periphery, and penetrates from the distal end surface to the proximal end surface in the insertion direction. A fourth feature is that a hollow portion having a substantially elliptical cross section is formed.

  As the intervertebral spacer, it is preferable that the hollow portion having a substantially elliptical cross section is formed in a form in which the major axis of the substantially elliptical cross section is positioned in the vertical direction and the minor axis is positioned in the horizontal direction.

  According to the intervertebral spacer of the present invention, the intervertebral spacer is a metal intervertebral spacer that is inserted and disposed between the vertebrae, wherein one or a plurality of voids are formed in the thickness in the thickness direction. Elasticity is applied to the load applied between the vertebrae by the part, so that the impact load applied between the upper and lower vertebrae while securing an appropriate gap between the upper and lower vertebrae while being a metal intervertebral spacer Such a load can be absorbed by elastic deformation. Therefore, it is possible to eliminate the fact that the intervertebral space adjacent to the intervertebral space having the intervertebral spacer is easily damaged by impact.

  In addition, since the properties of the metal are exhibited, it is possible to sufficiently prevent chipping or breakage that is likely to occur at the end or corner of a resin or inorganic material spacer. Therefore, the problem that the broken pieces are scattered in the vicinity of the intervertebral portion does not occur. Of course, the flexibility can be sufficiently exhibited in response to the spine to bend according to the movement of the person.

  The intervertebral spacer can be easily inserted and arranged by forming a gap having a shape corresponding to the intervertebral spacer at a predetermined intervertebral position.

  Further, according to the intervertebral spacer of the present invention, the upper surface is in contact with the upper vertebra, the lower surface is in contact with the lower vertebra, the distal end surface and the proximal end surface in the insertion direction, and is positioned between the upper vertebra and the lower vertebra. The upper vertebrae can receive the upper vertebra with a sufficient area by the upper surface of the substantially rectangular parallelepiped shape, and the lower surface of the substantially rectangular parallelepiped shape has a sufficient area. Can touch the vertebrae. Of course, since the voids (such as hollow portions and slits) are formed within the thickness in the thickness direction, no voids are formed on the upper and lower surfaces. Therefore, the upper and lower surfaces can be brought into contact with the vertebra as sufficiently wide and flat surfaces, and a load can be stably received.

  Further, in the intervertebral spacer, the horizontal hollow portion is formed in a form penetrating from the distal end surface to the proximal end surface at a portion located substantially in the center in the thickness direction, and the horizontal slit portion is formed between the horizontal hollow portion and the upper surface. Are formed at a certain depth from each of the left and right lateral surfaces from the distal end surface to the proximal end surface, respectively, at a portion located approximately in the middle of the horizontal hollow portion and a portion located substantially midway between the horizontal hollow portion and the lower surface. It is possible to make the ratio of the space due to the gap portion in the thickness direction sufficiently uniform throughout the entire area while maintaining the strength of the spacer. Therefore, it is possible to maintain the strength at a predetermined level while maintaining appropriate and uniform elasticity in the intervertebral spacer.

  Further, in this intervertebral spacer, by forming a horizontal slit portion from the distal end surface to the proximal end surface at a certain depth from the left and right side surfaces at a position located approximately in the middle between the horizontal hollow portion and the upper and lower surfaces, The spine can be easily bent in the left-right direction.

  Further, according to the intervertebral spacer of the present invention, the intervertebral spacer has a substantially columnar shape in which a screw for screwing is formed on the side periphery, and is substantially on the end surface of either the distal end surface or the proximal end surface in the insertion direction. A horizontal slit portion having a certain depth is formed in a portion located in the center, and on the other end surface, a portion at a position substantially corresponding to the middle between the portion located at the substantially center where the horizontal slit portion is formed, and the upper end; When having a configuration in which a horizontal slit portion of a certain depth is formed in a portion corresponding to a position substantially in the middle between a portion located at the approximate center where the horizontal slit portion is formed, and a lower end, By forming screw holes for the intervertebral spacer between the upper and lower vertebrae, the intervertebral spacer can be easily inserted and placed by screwing between the vertebrae. And when inserting, the elasticity of the intervertebral spacer is added to the load between the upper and lower vertebrae by inserting and placing the intervertebral spacer so that the horizontal slit of the intervertebral spacer is perpendicular to the spine. In contrast, it can be sufficiently exerted.

  In addition, a horizontal slit portion having a constant depth is formed at a substantially central position on either one of the distal end surface and the proximal end surface in the insertion direction, and the other end surface is substantially intermediate between the approximately central position and the upper end. By forming a horizontal slit portion having a fixed depth at each position and a substantially intermediate position between the central position and the lower end, the ratio of the space by the slit in the thickness direction of the intervertebral spacer is sufficiently uniform throughout the entire area. In addition, the strength of the intervertebral spacer can be maintained. Therefore, it is possible to maintain the strength at a predetermined level while maintaining appropriate and uniform elasticity in the intervertebral spacer.

  Further, in this intervertebral spacer, a horizontal slit having a fixed depth is formed at a substantially central position on one of the distal end surface and the proximal end surface in the insertion direction, and the substantially central position is formed on the other end surface. Since a horizontal slit portion having a fixed depth is formed at a substantially intermediate position between the upper end and the upper end and a substantially intermediate position between the substantially central position and the lower end, bending of the spine in the front-rear direction is facilitated.

  Further, according to the intervertebral spacer of the present invention, the intervertebral spacer has a substantially cylindrical shape in which a screw for screwing is formed on the side periphery, and the cross section penetrates from the distal end surface to the proximal end surface in the insertion direction and has a substantially elliptical cross section. Since the hollow portion is formed, by forming a screw hole for the intervertebral spacer between the upper and lower vertebrae, the intervertebral spacer can be easily screwed between the vertebrae and easily inserted and arranged. And when inserting, the elliptical long axis of the intervertebral spacer is inserted and arranged so that it is in the same direction with respect to the spine, and the elasticity of the intervertebral spacer is exhibited in the upper and lower vertebrae be able to.

  By forming an elliptical cavity through the proximal end surface from the distal end surface of the intervertebral spacer, the thickness of the intervertebral spacer in the vertical direction is reduced, and the thickness of the intervertebral spacer is increased in the horizontal direction, thereby increasing the vertical vertebrae. With respect to the load applied between them, the impact can be absorbed by elastically compressing in the vertical direction while maintaining the strength of the intervertebral spacer.

  In terms of shape, it is a simple shape in which an elliptical hole is provided through a cylindrical shaft core that is threaded on its side, making it easy to manufacture and process, and durable in terms of strength. It can be sexually superior.

An intervertebral spacer according to an embodiment of the present invention will be described with reference to the following drawings.
FIG. 1 shows an example of a state in which an intervertebral spacer according to the present invention is inserted and arranged between vertebrae of a spine, wherein (A) is a front view and (B) is a longitudinal sectional view. FIG. 2 is a perspective view of the intervertebral spacer according to FIG. 3 shows the intervertebral spacer according to FIG. 1, wherein (A) is a front view, (B) is a side view, and (C) is a plan view.

  FIG. 4 is a perspective view showing an example of an intervertebral spacer according to another embodiment of the present invention. FIG. 5 shows the intervertebral spacer according to FIG. 4, wherein (A) is a front view and (B) is a side view.

  FIG. 6 is a perspective view showing an example of an intervertebral spacer according to another embodiment of the present invention. 7 shows the intervertebral spacer according to FIG. 6, wherein (A) is a front view and (B) is a side view.

  The intervertebral spacer of the present invention is a metal intervertebral spacer that is inserted and arranged between the vertebrae, and one or a plurality of voids are formed in the thickness in the thickness direction. The intervertebral spacer is provided with elasticity against the load applied between the vertebrae. Thus, even if it is a metal intervertebral spacer, by forming one or more voids that can give elasticity to the load applied between the vertebrae within the thickness in the thickness direction, In addition, while securing an appropriate gap between the upper and lower vertebrae, a load such as an impact load applied between the upper and lower vertebrae (a load due to a load or an impact) can be absorbed by elastic deformation. Moreover, since it is made of metal, it is possible to effectively prevent the occurrence of chipping or breakage at the end or corner of the intervertebral spacer. Therefore, the intervertebral spacer of the present invention can sufficiently absorb the load and impact applied between the vertebrae and has good mechanical strength and is less likely to be damaged or chipped.

  In the intervertebral spacer of the present invention, as the gap portion, at least one of a hollow portion of a double-sided opening formed from one surface to the other surface and a concave slit portion formed on either surface. In particular, a hollow portion having a double-sided opening formed from the distal end surface to the proximal end surface in the insertion direction, a concave slit formed on the distal end surface or the proximal end surface in the insertion direction, and right and left perpendicular to the insertion direction It is preferable that it is at least one kind of gap portion selected from concave slit portions formed on any side surface in the direction. By setting it as such a space | gap part, it becomes possible to absorb loads, such as an impact load applied between the upper and lower vertebrae (a load by a load, an impact, etc.) by elastic deformation.

  The intervertebral spacer 10 according to the present invention will be described with reference to FIGS. The intervertebral spacer 10 is inserted and arranged at the position of the intervertebral disc 1b between the vertebrae 1a and 1a constituting the spine 1. That is, the spine 1 includes the lumbar vertebrae and the cervical vertebrae, and is composed of an alternating arrangement of the vertebrae 1a and the intervertebral disc 1b therebetween, but when the intervertebral disc 1b does not fulfill its role sufficiently, a predetermined interval is provided between the vertebrae 1a. An intervertebral spacer 10 is secured and inserted.

  FIG. 1A is a front view of the intervertebral disc 1b of the spine 1 and the upper and lower vertebrae 1a as seen from the front. The central portion of the intervertebral disc 1b is excised to secure a space, and the intervertebral spacer 10 is removed. Insert and place.

  The intervertebral spacer 10 includes an upper surface 10a in contact with the upper vertebra, a lower surface 10b in contact with the lower vertebra, a left side 10c positioned on the left side between the upper vertebra and the lower vertebra, an upper vertebra and a lower vertebra. It is configured in a substantially rectangular parallelepiped shape including a right side surface 10d positioned on the right side, a distal end surface 10e in the insertion direction, and a proximal end surface 10f in the insertion direction. In the intervertebral spacer 10, the shape of the substantially rectangular parallelepiped is a slightly flat shape in which the thickness dimension in the vertical direction is shorter than the width dimension in the horizontal direction. Of course, it is important that the thickness dimension in the vertical direction of the intervertebral spacer 10 is adjusted in advance to a dimension corresponding to the vertical dimension of the intervertebral disc space to be actually inserted. Similarly, an appropriate dimension is selected for the width dimension in the left-right direction of the intervertebral spacer 10 according to the left-right dimension of the intervertebral disc space to be inserted.

  When the intervertebral spacer 10 is inserted and arranged between the vertebrae 1a, the upper surface 10a is in contact with the upper vertebra 1a, and the lower surface 10b is in contact with the lower vertebra 1a.

  The intervertebral spacer 10 is made of metal. As described above, the metal for forming the intervertebral spacer is not particularly limited, but it is important to use a metal that is stable in vivo. Examples of such metals include titanium (pure titanium), titanium alloys, stainless steel, cobalt chromium alloys, zirconium, zirconium alloys, niobium, niobium alloys, tantalum, tantalum alloys, and the like, and simple metals and alloys. Among these, titanium and a titanium alloy are preferable, and a titanium alloy is particularly preferable. That is, the metal intervertebral spacer 10 is optimally made of a titanium alloy.

  In the intervertebral spacer of the present invention (in addition to the intervertebral spacer 10 described above, the intervertebral spacer 20 and the intervertebral spacer 30 described below), the titanium alloy contains titanium element as a main component, and other metal elements. As long as it is an alloy containing one or more of these. In a titanium alloy, the titanium element as a main component should just be a main component, for example, when the total amount of titanium alloys is 100 mass%, it may be 50 mass% or more. The crystal structure of the titanium alloy is not particularly limited, and examples include a hexagonal close-packed structure (α-type titanium alloy), a body-centered cubic structure (β-type titanium alloy), and an α-β-type titanium alloy. it can.

  In the titanium alloy, the metal element other than the titanium element is not particularly limited, and may be any metal element of a typical metal element, a semimetal element, and a transition metal element. For example, in the periodic table of elements, the group 3A Elements contained in (such as scandium), elements included in group 4A (such as zirconium and hafnium), elements included in group 5A (such as vanadium, niobium, tantalum), elements included in group 6A (such as chromium and molybdenum), Elements included in Group 7A (such as manganese), elements included in Group 8 (iron, cobalt, nickel, palladium, platinum, etc.), elements included in Group 1B, elements included in Group 2B, elements included in Group 3B (Aluminum, etc.) Elements included in Group 4B (tin, etc.) can be mentioned.

  In the present invention, in the titanium alloy, as the metal element other than the titanium element, scandium (Sc), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr ), Molybdenum (Mo), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), palladium (Pd) and aluminum (Al) are preferred. .

  In addition to the titanium alloy, the metal element constituting the alloy can be appropriately selected from the metal elements exemplified for the titanium alloy.

  In addition, for metals such as titanium alloys, carbon element (atom) (C), silicon element (Si), boron element (B), oxygen element (O), nitrogen element (N), hydrogen element as necessary (H) etc. may be included.

  In the present invention, as the titanium alloy, specifically, for example, a so-called “Ti-6Al-4V” titanium alloy (a titanium alloy containing 6% by weight of aluminum and 4% by weight of vanadium and basically the balance being titanium). Ti-Al-V titanium alloy, Ti-Al-Sn titanium alloy, Ti-Al-Nb titanium alloy, Ti-Al-Fe titanium alloy, Ti-Sn-Zr-Al titanium Alloy, Ti-V-Cr-Al series titanium alloy, Ti-Mo-Zr series titanium alloy, Ti-Al-Mo-V series titanium alloy, Ti-Al-Sn-Zr-Mo series titanium alloy, Ti-V- Fe-Al system titanium alloy, Ti-V-Al-Sn system titanium alloy, Ti-Zr-Nb-Ta-Pd system titanium alloy, Ti-Zr-Nb-Ta system titanium alloy, Ti-Al-Mo-Zr system Chita Alloy, Ti-Sn-Nb-Pd titanium alloy, Ti-Nb-Zr titanium alloy, Ti-Mo-Zr-Fe titanium alloy, Ti-Mo-Nb titanium alloy, Ti-Mo titanium alloy, Ti -Ta system titanium alloy, Ti-Ni system alloy, Ti-Pd system titanium alloy, Ti-Al system titanium alloy etc. are mentioned.

  In the present invention, a Ti-Al-V titanium alloy (particularly, Ti-6Al-4V) can be suitably used as the titanium alloy.

  In the intervertebral spacer 10, a horizontal hollow portion 11 and a horizontal slit portion 12 are formed in the vertical thickness of the intervertebral spacer 10. That is, the horizontal hollow portion 11 is a hollow portion having a double-sided opening formed from one surface to the other surface (specifically, a hollow portion having a double-sided opening formed from the distal end surface to the proximal end surface in the insertion direction). The horizontal slit portion 12 is a concave slit portion formed on any surface (specifically, a concave slit formed on any side surface in the left-right direction perpendicular to the insertion direction). Part).

  Specifically, the horizontal hollow portion 11 penetrates from the distal end surface 10e to the proximal end surface 10f in a portion (substantially central position) located in the approximate center of the intervertebral spacer 10 in the vertical direction (that is, the thickness direction). Is formed. In short, the horizontal hollow portion 11 is a through hole having a flat cross section having a constant width W1 and a thickness T1, and is generally symmetrical in the left-right direction of the intervertebral spacer 10.

  In addition, the horizontal slit portion 12 is located on the left side at a position (substantially intermediate position) between the horizontal hollow portion 11 and the upper surface 10a and a substantially intermediate position between the horizontal hollow portion 11 and the lower surface 10b. A slit portion having a constant depth W2 and a thickness T2 is formed from the surface 10c and the right side surface 10d.

  Each of the four horizontal slit portions 12 is formed from the distal end surface 10e to the proximal end surface 10f. The four horizontal slit portions 12 are generally formed symmetrically with respect to the intervertebral spacer 10 together with the horizontal hollow portion 11.

  In the present invention, it is preferable that the horizontal slit portions 12 from the left and right side surfaces 10c and 10d have such a depth that a portion thereof overlaps with a portion of the horizontal hollow portion 11. That is, each end on the left and right side surfaces (10c, 10d) side of the horizontal hollow portion 11 is located on the left and right side surfaces from the bottom (inner side end portion) of the horizontal slit portion 12 formed on each left and right side surface (10c, 10d). It is preferably located on the (10c, 10d) side. Specifically, the end portion of the horizontal hollow portion 11 on the left side surface 10c side is positioned on the left side surface 10c side from the bottom portion (end portion on the inner side) of the horizontal slit portion 12 formed on the left side surface 10c. The end portion of the horizontal hollow portion 11 on the right side surface 10d side is preferably positioned on the right side surface 10d side from the bottom portion (end portion on the inner side) of the horizontal slit portion 12 formed on the right side surface 10d. In other words, the bottom (inner side end) of the horizontal slit portion 12 formed in the left side surface 10c is located on the inner side from the end portion on the left side surface 10c side of the horizontal hollow portion 11, and the right side It is preferable that the bottom (inner side end) of the horizontal slit portion 12 formed on the surface 10 d is located on the inner side of the right side surface 10 d side end of the horizontal hollow portion 11. In this way, when the horizontal slit portion is formed so as to overlap with the horizontal hollow portion in a part in the left-right direction when viewed from the upper surface or the lower surface, the intervertebral spacer is subjected to a load applied between the vertebrae. On the other hand, elasticity can be more effectively imparted. In addition, as FIG. 1-3 shows, the horizontal slit part 12 and the horizontal hollow part 11 are independently formed, and are not integrated. That is, the overlap in this case means that there is an overlapping portion in the width direction of the horizontal hollow portion or the depth direction of the horizontal slit portion (that is, the left-right direction) when viewed from the upper surface or the lower surface. The horizontal slit portion and the horizontal hollow portion are not continuously formed (integrated) by overlapping.

  1 to 3, the overlapping dimension of each horizontal slit portion 12 and the horizontal hollow portion 11 (that is, in the left-right direction between the bottom portion of the horizontal slit portion 12 and the left side or right side end of the horizontal hollow portion 11. The horizontal distance of the horizontal hollow portion 11 is about 1/3 of the left side of the width W1 of the horizontal hollow portion 11 overlapping the two horizontal slit portions 12 and 12 from the left side surface 10c, and the width W1 of the horizontal hollow portion 11 is About 1/3 of the right side of the right side of the right side surface 10d overlaps the two horizontal slit portions 12 and 12. Moreover, in FIGS. 1-3, the overlap dimension with the horizontal hollow part 11 of each horizontal slit part 12 is about 1/2 of the depth W2 of the horizontal slit part 12. FIG.

  In the present invention, the overlapping dimension of each horizontal slit portion 12 and the horizontal hollow portion 11 is 1/5 to 4/5 (preferably 1/4 to 2/3) on the left or right side of the width W1 of the horizontal hollow portion 11. More preferably, it can be appropriately selected from a range of dimensions corresponding to 1/4 to 1/2, particularly preferably 1/3.

  In the present invention, the overlapping dimension between each horizontal slit portion 12 and the horizontal hollow portion 11 is 1/4 to 3/4 (preferably 1/3 to 2/3) of the depth W2 of the horizontal slit portion 12. More preferably, it can be appropriately selected from a range of dimensions corresponding to 2/5 to 3/5, particularly preferably 1/2).

  The width W1 of the horizontal hollow portion 11 and the depth W2 of each horizontal slit portion 12 are not particularly limited. The width W1 of the horizontal hollow portion 11 is, for example, 2/5 to 3/4 (preferably 1/2 to 2/3, more preferably 3/5) with respect to the width in the left-right direction of the intervertebral spacer 10. It can select suitably from the range. Further, the depth W2 of each horizontal slit portion 12 is, for example, 1/4 to 2/3 (preferably 1/3 to 1/2, more preferably 2/2) with respect to the lateral width of the intervertebral spacer 10. It can be appropriately selected from the range of 5).

  Moreover, in FIGS. 1-3, the thickness T1 of the horizontal hollow part 11 and the sum total of thickness T2, T2 of the two horizontal slits 12 and 12 of the left side surface 10c are the same grade, The total of the thickness T1 and the thicknesses T2 and T2 of the two horizontal slits 12 and 12 on the right side surface 10d are approximately the same.

  The thickness T1 of the horizontal hollow portion 11 and the thickness T2 of each horizontal slit portion 12 are not particularly limited. As thickness T1 of the horizontal hollow part 11, it is suitably from the range of 1/6-1/2 (preferably 1/5-1/3, more preferably 1/4) with respect to the thickness of the intervertebral spacer 10, for example. You can choose. Further, the thickness T2 of each horizontal slit portion 12 is, for example, in the range of 1/12 to 1/4 (preferably 1/10 to 1/6, more preferably 1/8) with respect to the thickness of the intervertebral spacer 10. It can be selected more appropriately. Furthermore, the thickness T1 of the horizontal hollow portion 11 is, for example, 80% to 120% (preferably 90% to 110%) with respect to the sum of the thicknesses T2 and T2 of the horizontal slit portions 12 and 12 of the left side surface 10c or the right side surface 10d. Furthermore, it can be appropriately selected from a range corresponding to 100%.

  As a specific example, when the intervertebral spacer 10 has a horizontal width of 10 mm and a vertical dimension (ie, thickness) of 4 mm, the horizontal hollow portion 11 has a width W1 of 6 mm, a thickness T1 of 1 mm, and each horizontal slit portion. 12 has a depth W2 of 4 mm, a thickness T2 of 0.5 mm, and an overlapping dimension of the horizontal slit portion 12 and the horizontal hollow portion 11 of 2 mm (the left and right portions of the horizontal hollow portion 11 overlapping the horizontal slit portion 12 are 2 mm each horizontal. The intervertebral spacer 10 is configured such that the dimension of the overlapping portion of the horizontal slit portion 12 that overlaps the hollow portion 11 is 2 mm).

  As described above, by introducing the horizontal hollow portion 11 and the horizontal slit portion 12 within the thickness of the intervertebral spacer 10, the intervertebral spacer 10 is adjusted to a predetermined intervertebral thickness while the intervertebral spacer 10 is adjusted. By introducing a gap (space) within the thickness of the spacer 10, it is possible to impart appropriate elasticity to the intervertebral spacer 10 made of metal (particularly titanium alloy) instead of the intervertebral disc 1 b. Further, considering the thickness T1 of the horizontal hollow portion 11 and the thickness T2 of the horizontal slit portion 12, and when the horizontal hollow portion 11 and each horizontal slit portion 12 from both sides are viewed from the upper surface or the lower surface, they are equal in the left-right direction. By forming the overlapping portions, it is possible to provide more preferable uniform elasticity over the entire region of the intervertebral spacer 10 in the vertical direction.

  Of course, due to the presence of the horizontal slit portion 12 from the left and right side surfaces 10c, 10d, it is possible to follow the bending of the spine 1 in the left-right direction.

  In FIGS. 1 to 3, the upper surface 10 a and the lower surface 10 b of the intervertebral spacer 10 are each configured as an uneven surface (a jagged surface). In this way, by making the upper surface 10a and the lower surface 10b of the intervertebral spacer 10 into a jagged surface, the intervertebral spacer 10 is once inserted, and after the placement is determined, the intervertebral spacer 10 moves. It can prevent more reliably. The shape of the uneven surface formed on the upper surface or the lower surface is not particularly limited as long as it is a shape that can prevent the movement of the intervertebral spacer after being inserted and arranged between predetermined vertebrae. For example, the uneven surface formed on the upper surface or the lower surface may be an uneven portion with a jagged shape as shown in FIGS. 1 to 3, and the cross section is a wave shape (the convex portion and the concave portion are formed with curves. Shape).

  In the intervertebral spacer 10 of the present embodiment, one horizontal hollow portion 11 and two horizontal slit portions 12 are formed on the left and right sides, but the number of horizontal hollow portions 11 and the horizontal slit portions 12 The number is not particularly limited to this number. It is also possible to provide the horizontal hollow portions 11 and the horizontal slit portions 12 alternately in the thickness direction of the intervertebral spacer 10. Moreover, the horizontal hollow part 11 may be provided in the form disperse | distributed to the left-right direction instead of one in the same position of the thickness direction.

  An intervertebral spacer 20 according to another embodiment of the present invention will be described with reference to FIGS. 4 and 5. The intervertebral spacer 20 is inserted into the position of the intervertebral disc 1b between the vertebrae 1a and 1a constituting the spine 1 by screwing and is arranged. In this case, the intervertebral spacer 20 is inserted and arranged between the vertebrae 1a by opening a screw hole by excising the central portion of the intervertebral disc 1b and screwing the intervertebral spacer 20. This intervertebral spacer 20 is also made of metal. As a metal for forming the intervertebral spacer 20, for example, titanium, titanium alloy, stainless steel, cobalt chromium alloy, zirconium, zirconium alloy, niobium, niobium alloy, tantalum, tantalum alloy, etc. These are simple metals and alloys, and are most preferably made of a titanium alloy.

  The intervertebral spacer 20 has a substantially cylindrical shape, and a screw (screw) 21 for screwing is formed on the side periphery thereof. In the intervertebral spacer 20, a horizontal slit portion 22 having a constant depth is formed on a distal end surface 20 a in the insertion direction into the intervertebral disc space at a portion (substantially central position) located at the approximate center thereof. Further, the base end surface 20b of the intervertebral spacer 20 is fixed at a position (substantially intermediate position) corresponding to a position approximately in the middle between the approximate center position and the upper end, and an approximately intermediate position between the approximately center position and the lower end. Depth horizontal slit portions 23, 23 are formed. The horizontal slit portion 22 and the horizontal slit portion 23 are formed as concave slit portions formed on either surface (specifically, concave slit portions formed on the distal end surface or the base end surface in the insertion direction). Yes.

  4 and 5, the vertical dimension (that is, thickness) T3 of the horizontal slit portion 22 of the distal end surface 20a is the vertical dimension (that is, thickness) T4 of the two horizontal slit portions 23 and 23 of the base end surface 20b. , The same as the total of T4 (substantially the same). The thickness T3 of the horizontal slit portion 22 and the thickness T4 of each horizontal slit portion 23 are not particularly limited. The thickness T3 of the horizontal slit portion 22 is, for example, 1/12 to 1/6 (preferably 1/10 to 1/8, more preferably 1/9) with respect to the vertical dimension (that is, thickness) of the intervertebral spacer 20. ) Can be selected as appropriate. Further, the thickness T4 of each horizontal slit portion 23 is, for example, in the range of 1/24 to 1/12 (preferably 1/20 to 1/16, more preferably 1/18) with respect to the thickness of the intervertebral spacer 20. It can be selected more appropriately. Furthermore, the thickness T3 of the horizontal slit portion 22 is, for example, 80% to 120% (preferably 90% to 110%, more preferably 100%) with respect to the sum of the thicknesses T4 and T4 of the horizontal slit portions 23 and 23. It can select suitably from the corresponding range.

  In FIGS. 4 and 5, the horizontal slit portion 22 of the distal end surface 20a and the two horizontal slit portions 23, 23 of the proximal end surface 20b are identical to each other at a substantially intermediate position between the distal end surface 20a and the proximal end surface 20b. The depth is overlapping. That is, the bottom of the concave portion of the horizontal slit portion formed on one surface of the distal end surface 20a and the base end surface 20b is positioned on the other surface side than the bottom portion of the concave portion of the horizontal slit portion formed on the other surface. ing. Specifically, the bottom (inner side end) of the horizontal slit portion 22 formed on the distal end surface 20a side is the bottom portion (inner side end portion) of each horizontal slit portion 23 formed on the proximal end surface 20b side. Therefore, it is located on the base end face 20b side. In other words, the bottom portion (inner end portion) of each horizontal slit portion 23 formed on the base end face 20b side is more than the bottom portion (inner end portion) of the horizontal slit portion 22 formed on the distal end face 20a side. It is located on the front end face 20a side. 4 and 5, the horizontal slit portion 22 and the horizontal slit portions 23 and 23 are overlapped with each other, for example, about 1/2 of the depth W3 of the horizontal slit portion 22 overlaps with the horizontal slit portion 23 and is horizontal. About 1/2 of the depth W 4 of the slit portion 23 is a dimension that overlaps with the horizontal slit portion 22. Note that “overlap” in this case also has the same meaning as in the case of the horizontal slit portion 12 and the horizontal hollow portion 11 shown in FIGS. That is, the horizontal slit portion 22 and the horizontal slit portion 23 are independently formed (not integrated), and the depth of the horizontal slit portion 22 or the horizontal slit portion 23 when viewed from the upper surface or the lower surface. This means that there are overlapping portions in the vertical direction (that is, the insertion direction), and the horizontal slit portion 22 and the horizontal slit portion 23 are continuously formed (integrated) by overlapping. Absent.

  In the present invention, the overlapping dimension between the horizontal slit portion 22 and each horizontal slit portion 23 is 1/4 to 3/4 (preferably 1/3 to 2/3, more preferably, the depth W3 of the horizontal slit portion 22. It can be appropriately selected from a range of dimensions corresponding to 2/5 to 3/5, particularly preferably 1/2). In the present invention, the overlapping dimension between the horizontal slit portion 22 and each horizontal slit portion 23 is ¼ to ¾ of the depth W4 of each horizontal slit portion 23 (preferably １ ／ to 2/3, More preferably, it can be appropriately selected from a range of dimensions corresponding to 2/5 to 3/5, particularly preferably 1/2).

  In addition, the depth W3 of the horizontal slit part 22 and the depth W4 of each horizontal slit part 23 are not restrict | limited in particular. The depth W3 of the horizontal slit portion 22 is, for example, 1/2 to 4/5 (preferably 3/5 to 3/4, more preferably 2/3) with respect to the length of the intervertebral spacer 20 in the insertion direction. ) Can be selected as appropriate. Moreover, the depth W4 of each horizontal slit part 23 is 1 / 2-4 / 5 (preferably 3 / 5-3 / 4, more preferably with respect to the length of the insertion left-right direction of the intervertebral spacer 20, for example. 2/3) can be selected as appropriate.

  As a specific example, when the intervertebral spacer 20 is a size corresponding to a M9 screw (screw having a diameter (outer dimension) of 9 mm) and the length is 12 mm, the depth W3 of the horizontal slit portion 22 of the distal end surface 20a. 8 mm, thickness T 3 is 1 mm, depth W 4 of each horizontal slit 23, 23 of the base end face 20 b is 8 mm, thickness T 4 is 0.5 mm, and the dimension of the overlapping portion of the horizontal slit 22 and horizontal slit 23 is 4 mm. The intervertebral spacer 20 is configured.

  It is also possible to form the horizontal slit portion 22 of the intervertebral spacer 20 on the proximal end surface 20b and form the horizontal slit portions 23, 23 on the distal end surface 20a. Thus, in the present invention, the number of horizontal slit portions on the distal end surface side and the number of horizontal slit portions on the proximal end surface side are not particularly limited, and the number of horizontal slit portions on the distal end surface side or the proximal end surface side is , Respectively, can usually be selected from the range of 1 to 3, preferably, as shown in FIGS. 4 to 5, the number of horizontal slits on one side is 1, and the number of horizontal slits on the other side is 2.

  As described above, by introducing the horizontal slit portion 22 and the horizontal slit portion 23 within the thickness of the intervertebral spacer 20, the diameter of the intervertebral spacer 20 is adjusted to a predetermined intervertebral thickness, By introducing a gap (space) within the thickness of the spacer 20, it is possible to impart appropriate elasticity to the intervertebral spacer 20 made of metal (particularly titanium alloy) instead of the intervertebral disc 1 b. Further, when the thickness T3 of the horizontal slit portion 22 and the thickness T4 of the horizontal slit portion 23 are taken into consideration, and the horizontal slit portion 22 of the distal end surface 20a and the horizontal slit portion 23 of the proximal end surface 20b are viewed from the upper surface or the lower surface. By forming a partially overlapping state in the insertion direction, it is possible to impart more preferable uniform elasticity over the entire vertical direction of the intervertebral spacer 20.

  Of course, due to the presence of the horizontal slit portion 22 from the distal end surface 20a and the horizontal slit portions 23, 23 from the proximal end surface 20b, it is possible to follow the bending of the spine 1 in the front-rear direction.

  An intervertebral spacer 30 according to another embodiment of the present invention will be described with reference to FIGS. Similarly to the intervertebral spacer 20, the intervertebral spacer 30 has a substantially cylindrical shape in which a screw for screwing is formed on the side periphery, and is between the vertebrae 1 a and 1 a constituting the spine 1. The intervertebral disc 1b is inserted and arranged by screwing. The intervertebral spacer 30 is inserted and arranged between the vertebrae 1a by making a screw hole in the central portion of the intervertebral disc 1b and screwing the intervertebral spacer 30. This intervertebral spacer 30 is also made of metal. As the metal for forming the intervertebral spacer 30, as in the intervertebral spacer 10 and the intervertebral spacer 20, for example, titanium, titanium alloy, stainless steel, cobalt chromium alloy, zirconium, zirconium alloy, niobium, niobium alloy, Examples thereof include simple metals such as tantalum and tantalum alloys, alloys, and the like.

  The intervertebral spacer 30 has a substantially cylindrical shape, and a screw 31 for screwing is formed on the side periphery thereof. In the intervertebral spacer 30, a hollow portion (elliptical hollow) having a substantially elliptical cross section is formed at a portion (substantially central position) penetrating from the distal end surface 30 a to the proximal end surface 30 b in the insertion direction into the intervertebral disc space. Part) 32 is formed. The oval hollow portion 32 is usually configured such that the major axis of the ellipse is horizontal in the vertical direction and the minor axis is horizontal in the left-right direction with the intervertebral spacer 30 inserted and arranged between the vertebrae 1a.

  By introducing the oval hollow portion 32 through the intervertebral spacer 30, the intervertebral spacer 30 is a metal screw having a diameter corresponding to the gap dimension between the vertebra 1 a, and the elasticity required for the intervertebral space is obtained. It can be held.

  The diameter of the screw of the intervertebral spacer 30 is a dimension corresponding to the gap dimension of the upper and lower vertebrae as a target, depending on the position of the spine 1 to which the intervertebral spacer 30 is to be inserted.

  Further, the major axis dimension and minor axis dimension of the oval hollow portion 32 are determined by the diameter of the intervertebral spacer 30 and how much elasticity and strength the intervertebral spacer 30 has. By making the thickness of the intervertebral spacer 30 in the vertical direction thin and increasing the thickness in the horizontal direction, the intervertebral spacer 30 can sufficiently withstand the load applied between the upper and lower vertebrae 1a and provide appropriate elasticity. It becomes possible. The major axis dimension of the oval hollow part 32 is appropriately selected from the range of 60% to 85% (preferably 65% to 80%, more preferably 70% to 75%) with respect to the diameter of the intervertebral spacer 30, for example. be able to. The ratio of the major axis dimension to the minor axis dimension in the elliptical hollow portion 32 is, for example, minor axis dimension / major axis dimension = 0.5 to 0.70 (preferably 0.52 to 0.68, more preferably 0). .55 to 0.65).

  As a specific example, when the intervertebral spacer 30 has a size corresponding to a M9 screw (screw having a diameter (outer dimension) of 9 mm) and its length is 13 mm, the elliptical hollow portion 32 has a major axis of 6.5 mm. The minor axis can be 4 mm.

  As described above, by forming the elliptical hollow portion 32 through the intervertebral spacer 30, the thickness of the intervertebral spacer in the vertical direction can be reduced and the pressure in the horizontal direction can be increased. As a result, the load applied between the upper and lower vertebrae can absorb the impact by elastically compressing in the vertical direction while maintaining the strength of the intervertebral spacer.

  In addition, the shape is simple, with an elliptical hole penetrating a cylindrical shaft core with a threaded side, making it easy to manufacture and process, and durable in terms of strength. In particular, it can be made excellent.

  In addition, the manufacturing method of the intervertebral spacer of the present invention is not particularly limited. For example, it may be a method of manufacturing using a mold prepared in advance so that a predetermined gap is formed, and an appropriate shape is processed so that the predetermined gap is formed. A manufacturing method may be used. The intervertebral spacer of the present invention can also be manufactured by assembling appropriate parts. In the present invention, as a method of manufacturing the intervertebral spacer, a method of processing and manufacturing so as to form a predetermined gap is suitable.

  The processing method for forming the void is not particularly limited, and can be appropriately selected from void formation processing methods capable of forming a desired void. For example, a mechanical cutting method And laser processing methods. In the present invention, a mechanical cutting method (for example, a cutting method using a cutting machine tool such as a lathe or a milling machine) is suitable as the gap forming method. In addition, the temperature at the time of this process is not restrict | limited in particular, You may process at room temperature and you may process under a heating or cooling.

  Specifically, in the intervertebral spacer of the present invention, for example, a predetermined gap portion (such as a hollow portion with a double-sided opening or a concave slit portion) is formed in a metal member (such as a titanium alloy member) having an appropriate shape. It can manufacture by performing processing (cutting etc.) so that it may be performed.

  The intervertebral spacer of the present invention functions as a spacer having the function of an artificial disc. The intervertebral spacer of the present invention is used by being inserted between vertebrae. Therefore, it is important that the intervertebral spacer of the present invention is formed in a size suitable for the vertebrae at the site of use. In other words, it is important to adjust the size of the intervertebral spacer of the present invention according to the intervertebral space of the site to be used.

  In the intervertebral spacer of the present invention, the number of intervertebral spacers to be inserted between one vertebra can be set as appropriate depending on the location of the intervertebral space, and may be singular or plural. May be. For example, when intervertebral spacers are inserted between lumbar vertebrae, it is possible to increase the strength by inserting a plurality of intervertebral spacers between the vertebrae.

  In addition, when the intervertebral spacer has a screw for screwing on the side circumference, the screw meshes with the calculus, so the intervertebral spacer is inserted between the vertebrae with excellent fixation from the initial stage after surgery (initial stage of insertion). It becomes possible to do.

  In the present invention, the intervertebral spacer may be inserted into the intervertebral space either from the front or from the rear. The insertion direction of the intervertebral spacer can be set as appropriate depending on the position of the intervertebral space to be inserted. Specifically, in the case of cervical vertebrae or thoracic vertebrae, for example, an incision is made in the anterior side of the neck, the carotid artery is outward and the tracheoesophagus is deployed contralaterally (to reach the front of the vertebral body), and the disc is removed. The intervertebral spacer of the present invention can be disposed between the vertebrae by opening a hole in which the intervertebral spacer can be inserted between the vertebrae and inserting the intervertebral spacer into the hole in the predetermined intervertebral space. Thus, in the case of the cervical vertebra and the thoracic vertebra, since there is a spinal cord, it is preferable to insert an intervertebral spacer from the front.

  On the other hand, in the case of the outer cervical vertebra and lumbar vertebra, for example, by performing surgery from the rear, the disc is removed, a hole is inserted into the predetermined vertebra, and an intervertebral spacer can be inserted into the predetermined intervertebral hole. By inserting the spacer, the intervertebral spacer of the present invention can be placed between the vertebrae. Thus, in the case of the outer cervical vertebra and the lumbar vertebra, the intervertebral spacer can be inserted between the vertebrae from the rear.

  When inserting an intervertebral spacer between predetermined vertebrae, the insertion direction of the intervertebral spacer, the arrangement state of the intervertebral spacer in the intervertebral space after insertion, and the like are important. That is, it is important that the intervertebral spacer of the present invention is inserted into a predetermined position between predetermined vertebrae so as to be in a predetermined arrangement state in a predetermined insertion direction.

The example of the state which inserted and arrange | positioned the intervertebral spacer which concerns on this invention between the vertebrae of a spine is shown, (A) is a front view, (B) is a longitudinal cross-sectional view. It is a perspective view of the intervertebral spacer which concerns on FIG. The intervertebral spacer which concerns on FIG. 1 is shown, (A) is a front view, (B) is a side view, (C) is a top view. It is a perspective view which shows the example of the intervertebral spacer which concerns on other embodiment of this invention. The intervertebral spacer which concerns on FIG. 4 is shown, (A) is a front view, (B) is a side view. It is a perspective view which shows the example of the intervertebral spacer which concerns on other embodiment of this invention. The intervertebral spacer which concerns on FIG. 6 is shown, (A) is a front view, (B) is a side view.

Explanation of symbols

1 spine 1a vertebra 1b intervertebral disc 10 intervertebral disc 10a upper surface 10b lower surface 10c left side surface 10d right side surface 10e distal end surface 10f proximal end surface 11 horizontal hollow portion 12 horizontal slit portion 20 intervertebral spacer 20a distal end surface 20b proximal end surface 21 screw 22 horizontal slit portion 23 Horizontal slit part 30 Intervertebral spacer 30a End face 30b Base end face 31 Screw 32 Elliptical hollow part W1 Width W2 Width W3 Depth W4 Depth T1 Thickness T2 Thickness T3 Thickness T4 Thickness

Claims (12)

  It is a metal intervertebral spacer that is inserted and placed between vertebrae, and one or more gaps are formed in the thickness in the thickness direction, and the gaps provide a load against the vertebrae. The intervertebral spacer is characterized by being given elasticity.   2. The intervertebral space according to claim 1, wherein the gap portion is at least one of a hollow portion of a double-sided opening formed from one surface to the other surface and a concave slit portion formed on either surface. Spacer.   The void portion is a hollow portion having a double-sided opening formed from the distal end surface to the proximal end surface in the insertion direction, a concave slit portion formed in the distal end surface or the proximal end surface in the insertion direction, or any of the left and right directions perpendicular to the insertion direction. The intervertebral spacer according to claim 1 or 2, wherein the intervertebral spacer is at least one kind of void selected from a concave slit formed on the side surface.   It has a substantially rectangular parallelepiped shape consisting of an upper surface in contact with the upper vertebra, a lower surface in contact with the lower vertebra, a distal end surface and a proximal end surface in the insertion direction, and left and right lateral surfaces positioned between the upper vertebra and the lower vertebra. The intervertebral spacer according to any one of claims 1 to 3.   A horizontal hollow portion having a shape penetrating from the distal end surface to the proximal end surface is formed at a portion located substantially in the center in the thickness direction, the portion located substantially in the middle between the horizontal hollow portion and the upper surface, and the horizontal The intervertebral spacer according to claim 4, wherein a horizontal slit portion having a constant depth is formed from each of the left and right side surfaces from a distal end surface to a proximal end surface at a portion located approximately in the middle between the hollow portion and the lower surface. .   The intervertebral spacer according to claim 5, wherein the horizontal hollow portion has a flat cross section.   The intervertebral body according to any one of claims 4 to 6, wherein each end portion on the left and right side surfaces of the horizontal hollow portion is located on the left and right side surfaces from the bottom of the horizontal slit portion formed on each left and right side surface. Spacer.   The intervertebral spacer according to any one of claims 1 to 3, wherein the intervertebral spacer has a substantially cylindrical shape in which a screw for screwing is formed on a side periphery.   A substantially central portion in which a horizontal slit portion of a certain depth is formed in a portion located substantially in the center on either one of the distal end surface and the base end surface in the insertion direction, and the horizontal slit portion is formed on the other end surface. A portion at a position substantially corresponding to the middle of the upper end and a portion at a position approximately equivalent to the middle of the horizontal slit portion and a position corresponding to the middle of the lower end. The intervertebral spacer according to claim 8, wherein a horizontal slit portion is formed.   The bottom of the concave portion of the horizontal slit portion formed on one surface of the front end surface and the base end surface is located on the other surface side than the bottom of the concave portion of the horizontal slit portion formed on the other surface. 9. The intervertebral spacer according to 9.   The intervertebral spacer according to claim 8, wherein a hollow portion having a substantially elliptical cross section is formed so as to penetrate from the distal end surface to the proximal end surface in the insertion direction. The intervertebral spacer according to claim 11, wherein the hollow portion having a substantially elliptical cross section is formed such that the major axis of the substantially elliptical cross section is positioned in the vertical direction and the minor axis is positioned in the horizontal direction.

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