Implant for engagement between vertebrae, and implant kit

Abstract

To provide an implant for engagement between vertebrae.SOLUTION: An implant includes: a monolithic body (10) having a first edge at a first end (10a), a second edge at a second end (10b) opposite to the first end (10a), and an outer surface extending between the first edge and the second edge, the body defining a central axis extending through the first end (10a) and the second end (10b); a plurality of teeth (6) forming the first edge; and an abutment surface (7a) provided at a distance from the first or second edge and extending substantially transversely to the teeth (6). The abutment surface (7a) is configured to engage a portion of a vertebra or an endplate that serves for engagement with a vertebra.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an implant for intervertebral engagement and to an implant kit including such an implant. In particular, the present invention relates to an implant of the spacer type to be inserted between vertebrae. [Background technology]

[0002] A space holder for vertebrae, in particular for intervertebral discs, is known from US Pat. No. 5,702,451. The space holder comprises a jacket having an opening and first and second edges. The edges have circumferentially adjacent recesses each extending in a direction towards the other edge and a stopper provided on at least one of the edges, the stopper being spaced apart from the outer edge. The stopper is formed by a member having an outer contour corresponding to the inner contour of the jacket and a nose-like projection for engaging in the recess. The jacket may be cut to length.

[0003] U.S. Patent No. 7,547,325 describes a space keeper for insertion between two vertebrae having a variable axial length, the space keeper having a sleeve-like first member and a second member guided within the first member and axially movable relative to the first member to adjust the overall length. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 5,702,451 [Patent Document 2] U.S. Patent No. 7,547,325 Summary of the Invention [Problem to be solved by the invention]

[0005] The above types of space holders or keepers, also called spacers, may be used for a variety of purposes, such as spacers for one or more removed vertebrae or spacers for intervertebral discs, etc. Due to the variety of possible clinical applications, patient-specific conditions, and the different locations on the spine where such spacers are used, a large inventory of spacers of different sizes and with different characteristics is usually required to select the appropriate implant.

[0006] It is therefore an object of the present invention to provide an implant for intervertebral engagement and an implant kit that allows a reduction in the inventory of implants provided for surgery. [Means for solving the problem]

[0007] This object is solved by an implant according to claim 1 and a kit according to claim 15. Further developments of the implant are specified in the dependent claims.

[0008] According to one aspect of the invention, an implant for engagement between vertebrae includes a monolithic body with a first edge at a first end, a second edge at a second end opposite the first end, and an outer surface extending between the first and second edges, the body defining a central axis extending through the first and second ends, a number of teeth forming the first edge, and an abutment surface arranged at a distance from the first edge and extending substantially transversely of the teeth, preferably in a direction towards the central axis. The abutment surface is adapted to engage with a vertebra or a portion of an end plate serving for engagement with the vertebra. In a further development, a number of intermediate abutment surfaces are arranged axially along the length of the body.

[0009] The implant can be easily cut to a desired length. Thus, an implant with a desired length can be made available preoperatively to adapt the implant to the size of the intervertebral space in which the implant is intended to be placed. Optionally, the implant can be combined with a suitable end plate at one or both ends, for example after cutting, configured to engage with the vertebrae. Such an end plate can have suitable characteristics, such as a specific size, engagement structure, or lordosis angle. Preferably, the end plates at both ends can be removably connected to the implant body.

[0010] The mesh structure of the implant may promote tissue and vascular ingrowth. According to a further aspect, the implant is a length-adjustable implant, comprising a first tubular member, a second tubular member movably positionable within the first tubular member, and a length adjustment structure for adjusting an axial position of the second tubular member relative to the first tubular member. At least the second tubular member is a monolithic body comprising a first edge at a first end, a second edge at a second end opposite the first end, and an outer surface extending between the first and second edges, the body defining a central axis extending through the first and second ends, a plurality of teeth forming the first edge, and an abutment surface spaced from the first edge and extending substantially transversely of the teeth toward the central longitudinal axis.

[0011] With length-adjustable implants, the length of the implant can be adjusted in small steps or semi-infinitely. The end plates can be selected according to the requirements of the actual clinical application. In a further development, the second tubular member may be cut further in length so that even greater variability is provided.

[0012] The length adjustment structure allows for locking the position of the second tubular member relative to the first tubular member using friction between mating ramps, so that the axial position can be easily secured and released with an instrument.

[0013] Further, according to another aspect, a kit is provided that includes a first implant configured to be cut to length and a second implant, the length of which is preferably reversibly adjustable and which may be an endplate configured for removably attachment to the first implant or the second implant. Additional endplates for various purposes may be provided.

[0014] The kit thus provides a modular system that allows the construction of a large number of implants with different characteristics from a small selection of components, which contributes to reducing costs for hospitals.

[0015] According to further aspects, the implant is manufactured using additive manufacturing techniques such as laser sintering, laser melting, electron beam melting, fused deposition molding (FDM), etc. Such techniques allow the production of any three-dimensional shape from CAD data, especially complex shapes that are not or hardly capable of being produced by subtractive methods. The manufacturing can be tailored to the requirements of a particular patient application.

[0016] Further features and advantages will become apparent from the following detailed description of the embodiments with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 shows a perspective view of an implant according to a first embodiment. [Diagram 2] 2 shows a perspective view of the implant of FIG. 1 cut to a desired length and further cutting options. [Diagram 3] FIG. 3 shows a perspective exploded view of the implant of FIG. 1 or 2 having an endplate that can be removably attached to the implant. [Figure 4] 4 shows the implant of FIG. 3 in an assembled state. [Diagram 5] FIG. 2 shows a perspective view from above of the implant of FIG. 1. [Figure 6] FIG. 6 shows a bottom perspective view of the implant of FIG. 5. [Figure 7] FIG. 7 shows a side view of the implant of FIGS. 5 and 6. [Figure 8] FIG. 8 shows a top view of the implant of FIG. 5 to FIG. [Figure 9] FIG. 5 shows a perspective view from above of a first endplate of the implant of FIGS. 3 and 4 configured to be connected to a first end of the implant. [Figure 10] FIG. 10 shows a bottom perspective view of the end plate of FIG. 9. [Figure 11] FIG. 11 shows a top view of the end plate of FIGS. 9 and 10. [Figure 12] FIG. 12 shows a side view of the end plate of FIGS. [Figure 13] FIG. 5 illustrates a top perspective view of the second endplate shown in FIGS. 3 and 4 configured to be connected to a second end of an implant. [Figure 14] FIG. 14 illustrates a bottom perspective view of the second end plate of FIG. 13. [Figure 15] FIG. 15 shows a top view of the second end plate of FIGS. 13 and 14. [Figure 16] FIG. 16 shows a side view of the second end plate of FIGS. 13 to 15. [Figure 17] FIG. 2 shows a perspective exploded view of an implant according to a second embodiment. [Figure 18] FIG. 18 shows a perspective view of the implant of FIG. 17 in an assembled state. [Figure 19] FIG. 19 is a cross-sectional view of the implant of FIGS. 17 and 18, the cross-section being taken on a plane that includes the longitudinal axis of the implant and extends circumferentially through the center of the length adjustment mechanism. [Figure 20] FIG. 20 shows a front perspective view of a drive member of the length adjustment mechanism of the implant according to FIGS. 17 to 19. [Figure 21] 21 shows a rear view of the drive member of FIG. 20. [Figure 22] FIG. 22 shows a side view of the drive member of FIGS. 20 and 21. [Diagram 23] FIG. 20 shows a front perspective view of a locking member of the length adjustment mechanism of the implant according to FIGS. 17 to 19. [Figure 24] 24 shows a rear perspective view of the locking member of FIG. 23. [Diagram 25] 25 shows a cross-sectional view of the locking member of FIGS. 23 and 24. FIG. [Figure 26] FIG. 20 shows a bottom perspective view of an alternative end plate of the implant shown in FIGS. 17-19. [Figure 27] 27 shows a perspective view from above of the end plate of FIG. 26. [Figure 28] FIG. 28 shows a top view of the end plate of FIGS. 26 and 27. [Figure 29] FIG. 29 shows a side view of the end plate shown in FIGS. 26 to 28. [Diagram 30] 20 shows a perspective view of a tubular member of the implant of FIGS. 17-19 according to a further embodiment. FIG. [Diagram 31] 31 shows a perspective view of the tubular member of FIG. 30 cut in length. [Diagram 32] FIG. 1 shows a perspective view of a kit including an implant according to a first embodiment and a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] With reference to Figures 1 to 8, an implant 1 according to a first embodiment comprises a monolithic implant body 10 and, optionally, a first end plate 20 and a second end plate 30. The implant body 10 may be formed as a tubular mesh. The implant body has a first end 10a and an opposite second end 10b and defines a central axis L extending through the first end 10a and the second end 10b. In the illustrated embodiment, the central axis L is also the longitudinal axis of the elongated body. The outer envelope perpendicular to the central axis L of the implant body 10 may be cylindrical, elliptical or kidney-shaped, or may have any other shape suitable for placement between vertebrae. The mesh comprises openings 2 formed circumferentially at regular distances between the outer surface 3a and the inner surface 3b (Figure 8). The openings 2 may be rhombic and may have a longitudinal diagonal extending parallel to the central axis L of the implant body 10. Each opening 2 is mirror symmetrical with respect to the longitudinal diagonal of the rhombus. Axially adjacent rows 2a, 2b of openings 2 may be offset from each other by half the axial height of the openings 2. In this way, a grid is formed with webs 4a, 4b that intersect at an acute angle and form an equal angle with the longitudinal diagonal of the openings 2. In the circumferential direction, there may be an equal number of openings 2 in each row. The size of the openings 2 and the webs 4a, 4b is such that there is an integer number of openings 2 in one row.

[0019] The webs 4a, 4b form a first edge 5a at a first end and a second edge 5b at a second end 10b. Due to the intersecting webs 4a, 4b, the edge 5a is provided with teeth 6 arranged in a ring around the central axis L. The free ends of the teeth 6 may lie in a plane perpendicular to the central axis L. The free ends of the teeth 6 thus form the first end 10a and the second end 10b, respectively, of the body. It should be noted that the ring of teeth 6 in the illustrated embodiment is circular, since the body 10 has a cylindrical outer shape. However, the ring may have any other shape adapted to the outer shape of the body. In a variant embodiment, the free ends of the teeth may be arranged in a plane that includes an angle with the longitudinal axis L of the body.

[0020] At a position away from the first end 10a, a first abutment surface 7a or stopper is formed. The first abutment surface 7a serves as a support for the connection of the end plate 20 to the implant body at the first end 10a. More specifically, the first abutment surface 7a extends in a plane substantially perpendicular to the central axis L and may be substantially flat. The teeth 6 protrude axially from the first abutment surface 7a. The first abutment surface 7a comprises a plurality of radially extending webs 8 extending from the inner coaxial ring 9 to the teeth 6. Thus, the width of the webs 8 increases from the inner ring 9 radially outward. The webs 8 are arranged alternately with respect to the teeth 6. That is, the radially outer ends of the webs 8 terminate on the inner surface 3b in the gaps between successive teeth 6. The number of webs 8 therefore corresponds to the number of openings 2. In the circumferential direction, there are gaps 8a between the webs 8. The rings 9 and the webs 8 have a certain thickness in the axial direction, which may be about one-quarter of the height of the openings 2.

[0021] Finally, on each web 8 adjacent to a ring 9 there is a spike 800 pointing in both directions, i.e. to a first end 10a and to a second end 10b. The height of the spike 800 may be less than the height of the tooth 6.

[0022] The second end 10b has a second abutment surface 7b which is identical to the first abutment surface 7a and which is spaced apart from the free ends of the teeth 6.

[0023] At equidistant axial positions in the body 10, preferably at a distance of half the axial height of the rows of the mesh structure, a number of intermediate abutment surfaces 7 are formed, which are identical to the first abutment surface 7a and the second abutment surface 7b. More specifically, the further abutment surfaces 7 are provided in such a position that by cutting the implant body 10 in a plane perpendicular to the central axis L and at the center of the openings 2 in the axial direction to the desired length, an implant body is provided which is shortened by a multiple of half the axial length of one mesh row including half the openings 2. This defines cut segments, as shown in FIG. 2. Each intermediate abutment surface 7 may form a first abutment surface 7a after cutting, or a second abutment surface 7b if the implant body is shortened from the second end 10b. Also, the implant body has the same shape when turned upside down. Before cutting, the positions of the teeth 6 are offset in the circumferential direction from the positions of the teeth 6 of the adjacent segments.

[0024] Due to the structure of the abutment surfaces 7a, 7, 7b, longitudinal channels are formed by the gaps 8a between the webs 8 as well as the circumferential channels between the rings 9. This may increase the stability of the implant body 10.

[0025] The implant body 10 is preferably manufactured using additive manufacturing methods. In additive manufacturing, the implant body is built up layer by layer on the basis of three-dimensional data characterizing the shape and size of the implant body. As an example, powder-bed-based layer manufacturing techniques such as selective laser-melting (SLM) include applying layers of a building material, such as a powder, in particular a metal or plastic powder, onto a support surface and selectively solidifying or melting the powder at locations corresponding to the cross-section of the implant body in the respective layer. The application and melting of further layers of the implant body are then repeated until the implant body is completed. Data of the cross-section of the implant body in the respective layer and data for controlling the layer manufacturing machine are obtained from CAD or CAM data of the implant body and the corresponding slice data. In particular, undercuts and complex shapes can be built up. The manufactured implant body may show characteristics of the manufacturing process, such as a slightly rough surface or laser marks, in the elaborately prepared cut-off parts. This allows the manufacturing process to be identified. Other additive manufacturing processes such as electron beam melting, FDM (fused deposition molding) can also be considered.

[0026] With further reference to Figures 9-12, the first endplate 20 or upper endplate is configured to be connected to the first end 10a of the implant body 10. The first endplate 20 is a substantially flat tubular plate-like member having an outer surface 20a configured to engage the vertebrae, in particular the vertebral body, and an opposing inner surface 20b configured to engage the implant body 10. The outer contour of the endplate 20 may be substantially rectangular in top view with a width greater than the maximum outer width of the implant body 10, as shown in Figure 11. However, the shape of the endplate 10 may be any shape and / or size suitable for engagement with the vertebrae. The inner surface of the tube of the endplate 20 forms a ring 21, which may have a slightly smaller diameter than the ring 9 of the implant body. A projection 22 extends axially from the ring 21. The projection may be offset by 180° and is configured to slide along the inner surface of the ring 9 of the implant body 10. The projection 22 may have the shape of a portion of a cylindrical wall. The projections may serve to center the end plate 20 when it is attached to the implant body 10. A plurality of radially extending webs 23 are provided, extending radially outward from the ring 21. Between the webs 23, gaps 24 or openings are formed which serve to receive the ends of the teeth 6 of the implant body 10. The number of webs 23 thus corresponds to the number of teeth 6 of the implant body. Each gap 24 has a radially outer end 25 which corresponds to the position of the tooth 6. More particularly, the shape of the end 25 may be adapted to the shape of the end of the tooth 6, so that the tooth 6 can be snugly received therein. In particular, the side walls of the end 25 may be inclined at an angle at which the webs 4a, 4b of the mesh intersect.

[0027] When the end plate 20 is attached to the first end 10a of the implant body 10, the webs 23 of the end plate 20 abut against the webs 8 forming the first abutment surface 7a of the implant body 10. The projections 22 abut radially against the inner surface of the ring 9 of the implant body 10. The teeth 6 extend into the ends 25 of the gaps 24 between the webs 23.

[0028] The first end plate 20 may have a wedge shape to provide a lordotic angle. As can be seen particularly in FIG. 12, the end plate 20 is thicker on the first side 26a relative to the central axis L compared to the opposite side 26b. Various end plates 20 with different angles may be provided to provide a modular system. Furthermore, the outer surfaces 20a at the radially outer portion of the web 23 and radially outward from the end 25 of the gap 24 may each be provided with spikes 27 forming a ring around the central axis L. The spikes 27 may serve to engage the vertebrae. The spikes may have approximately the same width or may have a width slightly smaller than the web 23.

[0029] 13-16, the second endplate 30, or bottom endplate, is also a substantially flat tubular plate member having an outer surface 30a configured to engage a vertebral bone and an opposing inner surface 30b configured to connect to the implant body 10. The outer contour of the second endplate 30 may be the same as the outer contour of the first endplate 20, or may be different.

[0030] The second end plate 30 comprises an inner ring 31. Two projections 32, preferably located opposite each other, protrude from the inner surface 30b so as to be able to engage with and slide along the inner ring 9 of the second abutment surface 7b at the second end 10b of the implant body 10. The inner surface of the inner ring 32 therefore has an inner diameter somewhat smaller than the inner diameter of the ring 9. A number of webs 33 extend radially outward from the inner ring 32. The circumferential width of the webs 33 is therefore smaller adjacent to the inner ring 32 and increases radially outward. The number and position of the webs 33 correspond to the number and position of the webs 8 at the second abutment surface 7b of the implant body 10. Between the webs 33, gaps 34 or openings are provided, each of which has at its radially outer end a circumferentially enlarged portion 35 for receiving a tooth 6 of the second edge 7b of the implant body 10, respectively. The opposing side 35 a of the enlarged portion 35 may have a slope corresponding to the slope of the teeth 6 so that the ends of the teeth 6 can be matingly received in the enlarged portion 35 .

[0031] The outer surface 30a at the radially outer position of the web 33 is provided with spikes 37 similar to the spikes 27 of the first endplate 20 to aid in engagement with the vertebrae. The spikes 37 are thus arranged on a ring and may have a width less than the radially outer width of the web 33.

[0032] As seen particularly in FIG. 16, the second endplate 30 may also include a lordotic angle such that the thickness of the second endplate 30 is greater on one side 36a from the central axis L compared to the opposite side 36b. Different second endplates may be provided with different lordotic angles and / or different sizes and / or different engagement mechanisms for engaging the vertebrae. This may provide a modular system including only one implant body and several first and second endplates that can be combined with the implant body into an implant for engaging between two vertebral bodies.

[0033] The first end plate 20 and the second end plate 30 are also preferably manufactured by additive manufacturing methods as described above.

[0034] The implant body and the first and second end plates may be made of any biocompatible material, preferably titanium or stainless steel, or any other biocompatible metal or metal alloy or plastic material. As a biocompatible alloy, NiTi alloys, for example Nitinol, may be used. Other materials may also be magnesium or magnesium alloys. Biocompatible plastic materials for use may be, for example, polyether ether ketone (PEEK) or poly-L-lactide acid (PLLA). The end plates and the implant body may be made of the same material or different materials.

[0035] In use, first, the implant body 10 is used in its originally provided length and combined with any suitable first end plate 20 and / or second end plate 30. Alternatively, the implant body 10 may be cut to the desired length at a predetermined location so that an implant body having the same shape as the original implant body but a different length is provided. The shortened implant body is then combined with any suitable end plate to provide an implant to be placed between the vertebrae. The end plates 20, 30 are plugged into the first end 10a and second end 10b of the implant body, respectively. The shortened implant body may have teeth offset from the teeth of the cut segment, but can rotate due to its symmetry for connecting with the first end plate 20. The first end plate 20 receives the teeth 6 of the first end 10a in the enlarged portion 25. The second end plate 30 receives the teeth 6 of the second end 10b in the enlarged portion 35a of the hole 35. This rotatably fixes the end plates relative to the implant body. When the implant 1 is inserted between two vertebrae, the pressure of the vertebrae against the endplates keeps them firmly fixed to the implant body.

[0036] As shown in Figs. 17-19, a second embodiment of an implant 100 for engagement between two vertebrae includes a monolithic first tubular body 40 and a monolithic second tubular body 50 that is positionable within the first tubular body 40 and axially movable relative to the first tubular body. The first tubular body 40 and the second tubular body 50 are connected to each other via a length adjustment structure 60. The length adjustment structure 60 includes an advancement structure 70 provided on the second tubular member 50 and a drive member 80 provided on the first tubular member 40. Note that the first tubular member 40 and the second tubular member as well as parts of the length adjustment structure are preferably manufactured by additive manufacturing methods as described above. The length adjustment structure can be easily integrated into a monolithic part. Also, a locking member 85 is provided to lock the axial position of the second tubular member 50 relative to the first tubular member 40. The second end plate 30 is similar to the first embodiment and is configured to be connected to a first tubular member 40. Additionally, a modified first end plate 20' is provided which is configured to be connected to a second tubular member 50.

[0037] As shown in particular in Figures 17 and 18, the first tubular member 40 is a mesh cage with a first end 40a, an opposite second end 40b and a grid or mesh formed by a number of openings 2, preferably diamond-shaped openings 2. At the second end 40b, the edge is provided with a number of teeth 6. At a distance from the free ends of the teeth 6, an abutment surface 41 is formed, the abutment surface including an inner ring 42 and a number of webs 43 extending radially from the inner ring 42 to the teeth 6. The webs 43 may have a flat surface towards the first end 40a, may have a V-shaped groove extending radially towards the second end 40b, but may be flat towards the second end 40b. The teeth 6 are configured to be received in the enlarged portion 35 of the opening 34 of the second end plate 30. The web 33 of the second end plate 30 is configured to abut the web 43 of the first tubular member 40 when the second end plate 30 is attached to the first tubular member 40 .

[0038] The first tubular member 40 above the second end 40b is provided with a tubular portion 44, and the tubular axis t of the tubular portion 44 is substantially perpendicular to the central axis L. The tubular portion 44 includes an internal thread 45 configured to cooperate with a locking member 85. The axial extension of the tubular portion 44 may reach the first end 40a.

[0039] The second tubular member 50 comprises a mesh cage having a first end 50a, an opposite second end 50b and a mesh or grid formed by a plurality of preferably diamond-shaped openings 2 similar to the first tubular member 40 and teeth 6 forming an edge at the first end 50a. A first abutment surface 51 is provided at a distance from the free ends of the teeth 6 at the first end 50a. As with the implant body of the first embodiment, the abutment surface 51 comprises an inner ring 52 and radially extending webs 53 arranged at positions corresponding to the teeth 6. Between the radially extending webs 53, gaps 54 are provided.

[0040] The generally U-shaped portion 56 extends from the second end 50b to the gap between the teeth 6 on the abutment surface 52. The U-shaped portion 56 is open toward the second end 50b. In a direction perpendicular to the central axis L, the U-shaped portion 56 extends into the internal hollow space of the second tubular member 50, and an advancement structure 70 configured to engage with the drive member 80 is formed on one side of the U-shaped portion 56. The advancement structure 70 may be, for example, a ratchet structure or a toothed rack. The teeth 71 of the toothed rack are arranged one after the other in the axial direction. When the second tubular member 50 is inserted into the first tubular member 40 and the U-shaped portion 56 is aligned with the tubular portion 44 of the first tubular member 40, the U-shaped portion 56 abuts against the rear side of the tubular portion 44.

[0041] As can be further seen from Figures 20-25, the length adjustment structure 60 further comprises a drive member 80 and a locking member 85. The drive member 80 comprises, at its rear side, a pinion portion 81 configured to be inserted into the first tubular member 40. The pinion portion comprises teeth 81a configured to engage with a toothed rack of the advancement structure 70 in the second tubular member 40. Adjacent to the pinion portion 81, a conical portion 82 is formed, the conical portion 82 tapering in a direction away from the pinion portion 81. A recess 83 is formed at a front end of the drive member 80 for engaging a tool (not shown) for rotating the drive member 80.

[0042] The locking member 85 is a threaded member having an external thread 87 configured to cooperate with the internal thread 45 of the tubular portion 44 of the first tubular member 40. In the assembled state, a rear side 85a of the locking member 85 faces the second tubular member 50, and a front side 85b of the locking member 85 faces the outside of the first tubular member 40. The locking member 85 further comprises a conical through-hole 86 extending coaxially with the thread so as to taper conically from the rear side 85a to the front side 85b. The conical through-hole 86 is configured to receive the conical portion 82 of the drive member 80. The locking member 85 further comprises a radially extending recess 88 on its front side for engaging with a tool for threading the locking member 85 back and forth into the tubular portion 44.

[0043] In the assembled state, the locking member 85 is within the tubular portion 44 of the first tubular member 40, and the drive member 80 is disposed with its conical portion 82 in the conical through hole 86 of the locking member 85, with the pinion portion 81 engaged with the toothed rack of the second tubular member 50. The second tubular member 50 may be inserted within the first tubular member 40 such that the pinion portion 81 of the drive member 80 is in its uppermost position, i.e., adjacent the bottom of the inverted U-shaped portion 56. Rotating the drive member 80 by engagement with a tool moves the second tubular member 50 out of the first tubular member 40 to a desired extent. The relative position of the second tubular member 50 to the first tubular member 40 can be locked by threading the locking member 85 deep into the tubular portion 44 such that the conical surface of the conical portion 82 of the drive member 80 and the conical surface of the conical through hole 86 of the locking member 85 engage to frictionally lock the drive member 80 against further rotation. The lock can be released by rotating the locking member 85 in the opposite direction.

[0044] The third end plate 20' is configured to engage with the first end 50a of the second tubular member. As shown in Figs. 26-29, the third end plate 20' is similar to the first end plate 20, and the same or highly similar parts are given the same reference numerals and will not be described. The third end plate 20' may have a through hole 25 between the outer surface 20a and the inner surface 20b, which is located at the radially outer end of the web 23 adjacent to the spike 27. The through hole 25 serves to receive a part of the tooth 6 of the second tubular member 50, since the web 53 of the abutment surface 51 of the second tubular member 50 is at the same circumferential position as the tooth 6. At the inner surface 20b, a circular step 28 may be formed at a position radially outward from the through hole 25. The third end plate 20' is attachable to the second tubular member 50 such that the tooth 6 extends into the through hole 25.

[0045] The second end plate 30 is similar to the second end plate 30 of the first embodiment.

[0046] With reference to Figures 30 and 31, in a variation of the second embodiment, the second tubular member 50' can be cut to a desired length. For this purpose, an intermediate abutment surface 90 is formed at a distance from the first end 50a in such a position that when the second tubular member 50' is cut in a plane including the maximum width of the opening 2, the intermediate abutment surface 90 becomes the first abutment surface, as can be seen in detail in Figure 31. For this purpose, a portion of the second tubular member 50' can be cut out as shown, so that the intermediate abutment surface 90 becomes the first abutment surface. If the second tubular member is long enough, several intermediate abutment surfaces 90 can be provided. The second tubular member 50' can be used with a third end plate 20'. When the upper segment is cut out, the teeth 6 of the remaining second tubular member 50' are offset from the teeth 6 before cutting. Thus, similar to the first embodiment, the teeth 6 of the intermediate abutment surface 90 can engage in the gaps 24 between the webs 23 of the third end plate 20'.

[0047] FIG. 32 shows an implant and endplate kit comprising an implant 10 according to a first embodiment and an implant 100 according to a second embodiment, which can be used interchangeably with the same second or bottom endplate 30 .

[0048] Variations on the above described embodiment are contemplated. For example, the openings may have shapes other than diamond-shaped. The end plates may have other shapes, for example circular, oval, kidney-shaped, etc.

Claims

1. An implant for engagement between vertebrae, said implant comprising: a monolithic body (10, 40, 50, 50') having a first edge at a first end (10a, 40a, 50a), a second edge at a second end (10b, 40b, 50b) opposite said first end (10a, 40a, 50a), and an outer surface (3a) extending between said first edge and said second edge, said body defining a central axis (L) extending through said first end (10a, 40a, 50a) and said second end (10b, 40b, 50b); A plurality of teeth (6) forming said first edge; an abutment surface (7a, 41, 51) spaced axially from the first edge or the second edge such that the teeth (6) project above the abutment surface, the abutment surface extending substantially transversely to the teeth (6); Including, The implant, wherein the abutment surface (7a, 41, 51) is configured to engage with a vertebra or a part of an endplate (20, 20') serving for engagement with a vertebra.

2. 2. The implant according to claim 1, wherein the abutment surface (7a, 51) comprises a plurality of webs (8, 43, 53) extending radially relative to the central axis (L) and spaced apart from one another in the circumferential direction.

3. 3. The implant according to claim 1 or 2, wherein the abutment surface of the first end (10a) is a first abutment surface (7a) and a second abutment surface (7b) extends substantially across the tooth (6) and is spaced apart from the second edge, preferably the second abutment surface (7b) comprises a plurality of webs (8) spaced apart from one another in the circumferential direction and extending radially relative to the central axis (L), the second abutment surface (7b) being configured to engage with a vertebra or a portion of an end plate serving for engagement with a vertebra.

4. An implant according to any one of claims 1 to 3, wherein at least one further intermediate abutment surface (7, 90), preferably a plurality of further abutment surfaces, is provided axially between said first end (10a, 50a) and said second end (10b, 50b), preferably at an equal distance, said intermediate abutment surface (7, 90) being preferably identical to said abutment surface (7a) at said first end (10a, 50a).

5. The implant according to any one of claims 1 to 4, wherein the body (10, 40, 50, 50') comprises a mesh structure having a plurality of openings (2), some of which open at the first end (10a, 40a, 50a) and / or at the second end (10b, 40b, 50b) so that the teeth (6) are formed, preferably the openings (2) are rhomboidal with diagonals extending parallel to the central axis (L).

6. 6. An implant according to claim 4 or 5, wherein the body (10, 50') is configured to be cut in length at an axial position between the intermediate abutment surfaces (7, 90) such that one particular intermediate abutment surface along which the body is cut forms the first abutment surface (7a, 51) at the first end (10a, 50a) after cutting.

7. An implant according to any one of claims 1 to 6, wherein the shape of the body (10, 40, 50, 50') is tubular and the first abutment surface (7a, 41, 51) extends in a radially inward direction from the outer surface (3a).

8. 8. The implant according to claim 1, further comprising at least a first endplate (20, 20') configured to be detachably connectable to the first end (10a, 50a), the first endplate (20, 20') having an inner surface (20b) configured to be connected to the first end of the body and an opposing outer surface (20a) configured to engage a vertebra, the inner surface (20b) configured to abut against the first abutment surface (7a, 51) of the body, and a plurality of openings (25, 25') are provided in the first endplate (20, 20') into which the teeth (6) can engage to connect the first endplate (20, 20') to the body.

9. 9. The implant of claim 8, wherein the inner surface comprises a plurality of radially extending webs (23, 25'), the openings (25') being formed in the webs.

10. 10. The implant according to any one of claims 1 to 9, further comprising at least a second endplate (30) configured to be detachably connectable to the second end (10b, 40b), the second endplate (30) having an inner surface (30b) configured to be connected to the second end (10b, 40b) of the body (10, 40) and an outer surface (30a) configured to engage with a vertebra, the second endplate (30) having a plurality of openings (34, 35, 35a) in which the teeth (6) can engage at the second end (10b, 40b) to connect the second endplate to the body.

11. 11. The implant of claim 10, wherein the second end plate (30) comprises a plurality of radially extending webs (33), preferably the spaces (34) between the webs in the circumferential direction defining the openings.

12. 12. An implant according to any one of claims 1 to 11, wherein the body is formed as a first tubular member (40) and a second tubular member (50) is provided defining a further body and movably positionable within the first tubular member, and a length adjustment structure (60) is provided for adjusting the axial position of the second tubular member (50) relative to the first tubular member (40), preferably configured such that the second tubular member (50') is cut to length.

13. 13. The implant of claim 12, wherein the first tubular member (40) or the second tubular member (50) comprises a drive member (80), and correspondingly, the second tubular member (50) or the first tubular member (40) comprises an advancement structure (70), the drive member (80) being configured to engage within the advancement structure such that, when the drive member (80) is actuated, the second tubular member (50) moves axially relative to the first tubular member (40).

14. The implant of claim 13, wherein the length adjustment structure (60) further comprises a locking member (85) for locking the drive member (80) to fix the axial length of the implant, preferably the locking member (85) and the drive member (80) are configured to engage with each other via an inclined surface to lock the position of the drive member (80) by friction.

15. 1. A kit of implants for intervertebral engagement, comprising: A kit comprising a first implant (10) configured to be cut to length, a second implant (100) whose length is reversibly adjustable, preferably reversibly adjustable, and optionally an endplate (30) configured for removably attaching to said first implant (10) or said second implant (10), preferably said first implant being an implant according to any one of claims 1 to 11 and said second implant being an implant according to claims 12 to 14.

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