Intervertebral implant
The intervertebral implant with a double wedge design addresses the issues of complexity and vulnerability in existing implants by enabling controlled, time-delayed movements, ensuring reliable and efficient integration with vertebrae.
Patent Information
- Application Number
- JP2022541933
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2020-01-21
- Filing Date
- 2021-01-15
- Publication Date
- 2025-09-29
- Estimated Expiration
- 2041-01-15
AI Technical Summary
Existing intervertebral implants are cumbersome and prone to failure due to the presence of additional movable members, such as an intermediate body, leading to potential bends and pinches during installation and operation.
The intervertebral implant features a double wedge with two inclined bodies having differently oriented surfaces, allowing for lateral and vertical movements of the support with a time delay, eliminating the need for an intermediate body and reducing the risk of damage by ensuring reliable function.
The solution provides a more reliable and efficient installation process by allowing controlled, time-delayed movements of the support, minimizing the risk of damage to the vertebrae during expansion and ensuring stable integration with the vertebrae.
Smart Images
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Abstract
Description
[Technical Field]
[0001] The present invention relates to an intervertebral implant having at least two upper and two lower contact bodies with contact surfaces, an actuator having a screw body with opposite threads arranged side by side and having an extension axis, and a wedge axially movably seated on the screw body and capable of running along the screw body by rotation of the screw body, the wedge having inclined surfaces of at least one inclined body of the wedge engaging at least opposing surfaces of at least a portion of the contact bodies and extending at a finite angle of less than 90° relative to each other. [Background technology]
[0002] Patent document 1 discloses an intervertebral implant according to a general concept, in which the individual contact bodies of the intervertebral implant can move laterally apart and vertically apart, with the lateral movement being achieved by an actuator having a threaded rod with opposing threads via a sliding body that is inclined on the opposing threads and axially slidable, and the sliding body engages with the corresponding opposing surfaces of the contact bodies.
[0003] The vertical movement of the contact bodies away from each other is effected indirectly via an intermediate body arranged between the wedge and the support, the intermediate body being slidable within an obliquely extending groove in the lower support.
[0004] This type of arrangement is on the one hand cumbersome and on the other hand vulnerable to failure, since in addition to the wedge and the support there is an intermediate body provided as an additional movable member, since this can result in bends and pinches. [Prior art documents] [Patent documents]
[0005] [Patent Document 1] US Patent Application Publication No. 2019 / 0269521 [Patent Document 2] International Publication No. 2014 / 146797 Summary of the Invention [Problem to be solved by the invention]
[0006] The object of the present invention is therefore to create an intervertebral implant that avoids the above-mentioned drawbacks, is easy to install, allows the support to move in different directions with a time delay, and yet ensures reliable function. [Means for solving the problem]
[0007] According to the present invention, the above problem is solved by a related intervertebral implant, which is characterized in that the wedge is configured as a double wedge with two inclined bodies arranged side by side in the direction of the extension axis, the inclined surface of one inclined body having a different orientation relative to the inclined surface of the other inclined body, the inclined surface of the first inclined body directly engaging the contact body laterally, while the inclined surface of the second inclined body directly engaging the contact body vertically.
[0008] The present invention therefore contemplates the presence of two axially arranged side-by-side ramps with differently oriented ramps in the same double wedge, the first ramp being used for lateral or sideways movement of the support away from each other, and the second ramp being used for vertical or craniocaudal movement of the support away from each other.
[0009] In particular here, the differently oriented inclined surfaces are arranged on different inclined bodies of a double wedge.
[0010] In a highly preferred configuration of the invention, the inclined surface of the first tilter is oriented perpendicular to the horizontal plane normal, and the plane normal of the inclined surface of the second tilter is oriented differently and forms a finite angle with the vertical that is not 90°. In a further development, the opposing surfaces of the contact bodies cooperating with the differently oriented inclined surfaces have a different spacing in the extension direction of the axis of the screw body of the actuator compared to the spacing of the differently oriented inclined surfaces, in particular the spacing of the differently oriented inclined surfaces is such that, when the screw body is rotated, the contact bodies move at least laterally apart and only then lift up relative to each other.
[0011] In a specific configuration, this can be achieved by the fact that the spacing of the inclined surfaces is such that, relative to the spacing of the opposing surfaces, the contact body first engages laterally with the opposing surface of the contact body via the inclined surface of the first inclined body, so that they move apart laterally, and only upon further rotation does the inclined surface of the second inclined body engage with the opposing surface of the contact body so as to lift it up, thereby specifically realizing a time-delayed movement of the support.
[0012] According to the invention, the distance between the differently oriented inclined surfaces of a double wedge having two inclined members can be smaller than the distance between the associated opposing surfaces.
[0013] In a further preferred configuration of the invention, the actuator has a radial disk or a radial wheel firmly connected to the threaded body, the wheel engaging in a slit in the contact body oriented radially relative to the axis of the threaded body to guide it perpendicular to the axis, and / or a guide rod in sliding engagement with at least the upper contact body is provided to guide the contact bodies relative to one another.
[0014] The lateral contact surfaces of the upper and lower contact bodies typically do not extend parallel to one another; rather, the lateral contact surface of the upper and lower contact bodies preferably forms an angle of 5° to 15°, preferably 9° to 11°, with respect to the lateral contact surface of the lower contact body, thereby achieving a natural lordosis with respect to the lumbar vertebrae. The proximal region of the contact surface of each individual contact body begins with a linearly ascending surface at half this angle relative to the horizontal central plane, then transitions to an opposite curvature in the distal region, forming a radius that also facilitates insertion into the intervertebral foramen.
[0015] In a preferred configuration, the ramp is integral with the double wedge.
[0016] In a highly preferred configuration, the overlapping and / or side-by-side contact bodies are movably connected to one another via linear guides, in particular at least one of which is a groove spring guide, preferably a dovetail guide, by means of which the forces occurring in the event of shear stress are guided through the contact bodies and do not, or at least only slightly, load the internal (functional) structure, as in the case of a double-screw sliding mechanism.
[0017] Further advantages and features of the invention emerge from the claims and the following description in which preferred embodiments of the invention are explained in detail with reference to the drawings. [Brief explanation of the drawings]
[0018] [Figure 1] 1 is an exploded view of a first intervertebral implant according to the present invention. [Figure 2] 2 is a perspective view of the drive mechanism of the implant according to the invention of FIG. 1 in a compressed state. [Figure 2a] FIG. 3 is a side view of the drive mechanism of FIG. 2. [Figure 3] FIG. 2 is a perspective view of the drive mechanism of the embodiment of FIG. 1 in an expanded state. [Figure 3a] FIG. 4 is a side view of the drive mechanism corresponding to FIG. 3. [Figure 4]2 is a perspective view of the double wedge of the implant according to the invention of FIG. 1; FIG. [Figure 4a] FIG. 5 is a plan view of the double wedge of FIG. 4. [Figure 4b] FIG. 5 is a side view of the double wedge of FIG. 4. [Figure 5] FIG. 1 shows a complete implant in a compressed state. [Figure 5a] FIG. 10 is a view of the implant in a compressed state with the upper anterior contact removed. [Figure 6] FIG. 1 shows the implant according to the first step in a lateral only expanded state. [Figure 6a] FIG. 7 is a view of the implant according to FIG. 6 according to the first step, only laterally in the expanded state and with the upper anterior contactor removed. [Figure 7] FIG. 10 is a view of an implant of the present invention in a laterally and vertically expanded state after a second expansion step. [Figure 7a] FIG. 8 shows an implant according to the invention in a laterally and vertically expanded state after the second expansion step according to FIG. 7 and with the upper anterior support removed. [Figure 8] FIG. 10 is an exploded view of another embodiment of an intervertebral implant according to the present invention. [Figure 9] FIG. 9 is a perspective view of another double wedge according to the configuration of FIG. 8. [Figure 10] FIG. 9 is a perspective view of the implant of FIG. 8 in a compressed state. [Figure 10a] FIG. 11 is a side view of the implant of FIGS. 8 and 10 in a compressed state. [Figure 11] FIG. 9 is an exploded view of the implant of FIG. 8 in a fully expanded state. [Figure 11a] FIG. 9 is a side view of the implant of FIG. 8 in a fully expanded state. [Figure 12] 10A and 10B show a variant embodiment of an intervertebral implant according to the invention in a compressed state and with a linear guide; [Figure 13] 13A and 13B are views of the embodiment of FIG. 12 in laterally and horizontally expanded states. [Figure 14]13 is a side view of the intervertebral implant according to the invention of FIG. 12 in the region of the upper right and lower contact bodies as seen from the engagement side. [Figure 15] FIG. 10 is a perspective view of the inside of the upper left contact body as viewed from the engagement side. [Figure 16] FIG. 10 is a bottom view of the lower contact bodies arranged side by side. DETAILED DESCRIPTION OF THE INVENTION
[0019] A first embodiment of an intervertebral implant according to the invention is shown in Figures 1 to 7a. The implant 1 has two upper contact bodies 2.1 and 2.2 (2.2 has been removed in Figures 5a, 6a and 7a) and two opposing lower contact bodies 2.3 and 2.4. An actuator or drive mechanism 3 is centrally located between them (see in particular Figures 3 and 3a).
[0020] The contact bodies 2.1-2.4 have upwardly or downwardly oriented contact surfaces, the central regions of which, e.g. 2.1.1, 2.2.1, 2.3.1, 2.4.1, are oriented substantially horizontally or form or define a horizontal region, while the contact surfaces are downwardly or curved at their ends in the longitudinal direction, with the opposing upper and lower contact surfaces extending opposite each other.
[0021] The drive mechanism 3 has a central screw body 4 with an axis A, which also determines the longitudinal direction of the implant. The screw body 4 has two oppositely directed threads 4.1, 4.2 arranged side by side. The thread 4.1 is a distal thread, and the thread 4.2 is a proximal thread. At its proximal end, the screw body 4 is formed with an engagement contour 4.4 for engagement with a tool (not shown), which can rotate the screw body 4. A guide wheel 4.3 is arranged in the center of the screw body 4 and is non-rotatably connected to it. The guide wheel engages in a radially oriented transverse slit 2.5 of the contact bodies 2.1-2.4, and determines and sets the relative axial positions of the contact bodies 2.1-2.4 and the screw body 4, regardless of the lateral and vertical movements of the contact bodies 2.1-2.4 relative to each other.
[0022] The threaded body 4 is fitted with a double wedge 5, 5a provided with an internal thread 5.3 that fits onto the threads 4.1, 4.2, and which comprises two tilting members that are mirror-symmetrically arranged on either side of the wheel.
[0023] Each double wedge 5, 5a has a first and a second inclined body 5.1, 5a.1, 5.2, 5a.2, which are arranged side by side in the direction of the axis A and point outward away from the wheel 4.3. The inclined surfaces 5.1.1 and 5.1.2 of the inclined body 5.1 extend outward away from each other and away from the wheel 4 as follows (Fig. 2): the inclined body 5.1 has inclined surfaces 5.1.1 and 5.1.2 as upper and lower inclined planes, respectively, which have a plane normal F5 that is at a finite angle other than 90° with respect to the normal V to the axis A (Figs. 2, 2a). The same applies to the other inclined surfaces of the inclined bodies.
[0024] The contact body 2.1 (and similarly the contact body 2.2) has an opposing surface 2.6 with approximately the same or exactly the same inclination relative to the inclined surface 5.1.1 as the inclined surfaces 5.1.1 and 5.1.2, and acts against the inclined surfaces 5.1.1 to 5.1.2 when the screw body 4 rotates and the double wedge 5 and the inclined body 5.1, and thus the inclined surfaces 5.1.1 and 5.1.2, move away from the wheel 4.3 and outward (to the left in the figure) along the axis A.
[0025] The same basically applies to the inclined body 5a.1 and the inclined surfaces 5a.1.1, 5a.1.2 present thereon, and a corresponding counter surface 2.1.3 is formed on the inside of the contact body 2.1. The same applies correspondingly to the corresponding inclined surface of the contact body 2.2 and to the lower inclined surface 5a.1.2 and the corresponding counter surfaces of the lower contact bodies 2.3 and 2.4.
[0026] The double wedge 5 has a ramp 5.2 offset inwards in the axial direction A relative to the ramp 5.1 and, as already mentioned, with ramps 5.2.1 and 5.2.2. These ramps are vertically oriented (also in FIG. 3) and also extend obliquely from one another outwards from the wheel 4.3, each having a surface normal F5.2 which is oriented horizontally, i.e. perpendicular to the vertical line V, and which, together with the axis A, form a horizontal plane (FIG. 3).
[0027] The inclined surface 5.2.1 cooperates with the similarly vertically oriented and obliquely extending opposing surface 2.4.2 on the contact body 2.4 and the corresponding opposing surface on the upper front contact body 2.3, so that when the double wedge 5 moves outward away from the wheel 4.3 due to rotation of the threaded body 4, the contact body 2.4 (and also the contact body 2.3) can move outward until it disengages from the opposing surface 2.4.2 of the inclined surface 5.2.1 (and the corresponding opposing surface of the contact body 2.3). Then, as the threaded body 4 continues to screw, the double wedge 5 can move along the contact bodies 2.4 and 2.3.
[0028] The same applies to the inclined surface 5.2.2 and the corresponding counter surfaces on the contact bodies 2.1 and 2.2, as well as to the corresponding inclined surfaces 5a.2.1, 5a.2.2 of the inclined body 5a.2 on the double wedge 5a (FIGS. 3, 3a). In that respect, reference is made to the above explanation regarding the cooperation of the inclined surface 5.2.1 and the counter surface 2.4.2.
[0029] In the first configuration of Fig. 1-7a, the ramp 5.2 has upper and lower projections 5.2. which extend laterally away from it and beyond the ramp surface 5.2.1. 1 . 2 (FIG. 2), which engages in the slot 2.1.4 of the contact body 2.1 and, due to the contact surface of the ramp 5.2, guides the contact body horizontally relative to one another when the contact body moves laterally away from the other. The same applies to the second projections of the ramps 5.2 and 5a.2 and the associated slots 2.3.4 of the ramps 2.1-2.4.
[0030] The slots 2.1.4 have a bend in their area facing the end face, which ensures the above-mentioned guidance when the contact bodies 2.1 and 2.3 or 2.2 and 2.4 move vertically away from each other under the action of the ramps 5.1, 5a.1.
[0031] The same applies to the illustrated protrusions in the region of the tilting body 5a.2 and the associated slits, e.g. 2.3.4a, and in this respect reference is made to the above explanations as well as to the corresponding protrusions on the opposite sides of the two tilting bodies and the corresponding slits in the contact bodies 2.1 and 2.2.
[0032] Finally, for example, between the contact bodies 2.1 and 2.2, there are further guide rods 6.1, 6.2 which can slide in the two tilt bodies 2.1, 2.2 and which are contact body guide each other during their lateral movement away from each other and their vertical stroke movement.
[0033] Corresponding guide rods are provided on the lower contact bodies 2.3 and 2.4, which guide these contact bodies relative to one another during the lateral and downward movements.
[0034] 1, it can be seen that the distance from the inclined body 5.2, and thus its inclined surface 5.2.1, to the inclined body 5.1 or its inclined surface 5.1.1 (and the corresponding inclined surface not visible) is smaller than the distance between the counter surface 2.4.2 and the counter surface 2.6 or the corresponding counter surface of the same contact body. The same also applies to the distance between the inclined bodies 5a.2 and 5a.1 or their inclined surfaces compared to the corresponding counter surfaces on the contact body.
[0035] As a result, in a first step, the upper contact bodies 2.1 and 2.2 as well as the lower contact bodies 2.3 and 2.4 are first moved away from each other in a lateral direction by the inclined bodies 5.2 and 5a.2 or their inclined surfaces, and only subsequently, i.e., at a time offset from the above step, the contact bodies 2.1 and 2.3 as well as the contact bodies 2.2 and 2.4 are moved away from each other in a perpendicular or vertical direction by the inclined bodies 5.1 and 5a.1 or their inclined surfaces, so that only in a laterally spread state can the contact bodies 2.1-2.4 be moved toward the upper and lower vertebrae, thereby reducing the risk of damage to the vertebrae.
[0036] An embodiment of the intervertebral implant according to the invention is shown in Figures 8 to 11a. This embodiment has essentially the same configuration as the first embodiment of Figures 1 to 7a. In this respect, the same elements are designated by the same reference numerals, and reference is made to the previous description of the first embodiment. The key difference with the slightly different configuration of the ramps 5.2 and 5.2a is the double wedge 5, 5a. This difference is that these double wedges exhibit lateral projections 5.2.5 and 5.2.6 on the ramp 5.2 and 5a.2.6 on the ramp 5a.2 on each side, instead of the two lateral projections of the corresponding ramps of the configuration of Figures 1 to 7a (the projection on the other side of the ramp 5a.2 is not visible in the figures). The projections 5.2.5, 5.2.6, and 5a.2.6 are arranged at half the height of the ramps 5.2 and 5a.2. The projections engage in the horizontally and then obliquely extending slits 2.1.5, 2.1.6, 2.2.5, 2.2.6, 2.3.5, 2.3.6, 2.4.5, 2.4.6, with the outwardly inclined portions of the slits 2.1.5, 2.1.6, 2.2.5, 2.2.6 of the upper contact bodies 2.1, 2.2 extending outwardly downwards, while the outwardly inclined portions of the slits 2.3.5, 2.3.6, 2.4.5, 2.4.6 of the lower contact bodies 2.3, 2.4 extending outwardly upwards.
[0037] This means that when the protrusions 5.2.5 and 5.2.6 (and the corresponding protrusions of the inclined body 5a) enter the inclined portions of the slits, the lower contact bodies 2.3 and 2.4 are pressed downward and the upper contact bodies 2.1 and 2.2 are pressed upward, thereby causing a vertical expansion of the contact bodies 2.1 and 2.2 relative to each other and to 2.3 and 2. 4 The mutual preceding horizontal spread is performed in the same way as described in connection with the first embodiment.
[0038] This allows the projections 5.2.5 and 5.2.6, as well as 5a.2.6 (and the corresponding projections of the ramp 5a.2) to simultaneously engage with the slits of the lower and upper contact bodies, respectively, and thus move vertically apart accordingly. For example, projection 5.2.5 moves into slit 2.3.5 of contact body 2.3 and into slit 2.1.5 of contact body 2.1, so that in the compressed basic configuration (FIGS. 10 and 10a), the slits must overlap. Therefore, the regions 2.1.7 and 2.2.7 with slits 2.1.5, 2.1.6, and 2.2.5, 2.2.6 engage vertically within the side walls of the corresponding contact bodies 2.3 and 2.4, so that the slits overlap in their horizontal regions. This can be easily understood by conceptually superimposing the contact bodies 2.1 and 2.3 on the one hand and 2.2 and 2.4 on the other hand in FIG. 8.
[0039] Figures 12 to 16 show further variations of the intervertebral implants of the preceding figures. Like elements are designated by like reference numerals. The intervertebral implants of Figures 12 to 16 similarly have upper contact bodies 2.1, 2.2 and lower contact bodies 2.3, 2.4. In Figure 12, the intervertebral implant 1 is shown in a compressed state, while in Figure 13 it is shown in a state in which it is only laterally or horizontally expanded.
[0040] The implant 1 first has linear guides 7.1 and 7.2 for the two upper contact bodies 2.1 and 2.2 (Figs. 12 and 13). It also has linear guides 7.3 and 7.4 for the two lower contact bodies 2.3 and 2.4 (Figs. 12, 13, 14 and 16). The linear guides 7.1-7.4 serve to guide the upper contact bodies 2.1 and 2.2 and the lower contact bodies 2.3 and 2.4 laterally or horizontally relative to each other. Corresponding vertical linear guides are also provided for the directly overlapping contact bodies 2.1 and 2.3 and 2.2 and 2.4. Only the vertical linear guide 7.5 for the contact bodies 2.2 and 2.4 is shown in the drawings, specifically Fig. 13, and will be described below.
[0041] Each linear guide 7.1-7.2 consists of a groove spring guide, in particular a dovetail guide with undercuts, as shown and understood for guide 7.3 in Figures 12, 13 and 16 and for guides 7.1 and 7.2 in Figures 13 and 15. The same applies to guide 7.5 in Figure 13.
[0042] Each linear guideway therefore has a groove and an engaging protrusion or projection, usually designated as a "spring." In linear guideway 7.1, this is groove 7.1.1 and spring 7.1.2; in linear guideway 7.2, this is groove 7.2.1 and spring or protrusion 7.2.2 (respectively Fig. 13); in linear guideway 7.3, this is groove 7.3.1 and spring 7.3.2; and in linear guideway 7.4, this is groove 7.4.1 and spring 7.4.2 (respectively Fig. 16).
[0043] In the vertical linear guide 7.5 shown in Fig. 13, a groove is formed between the two downwardly guiding guide projections 7.5.1 and 7.5.1a, and the corresponding spring or projection of the guide 7.5 is formed by the side wall 7.5.2 of the support body at the lower right when viewed from the engagement side. Here, the projection or spring 7.5.2 and the interacting side walls of the guide projections 7.5.1, 7.5.1a are likewise configured in a dovetail shape with undercuts, as can be seen from Fig. 13.
[0044] The vertical linear guides of the overlapping supports 2.1, 2.3 are also constructed in the same way as the linear guide 7.5.
[0045] By means of these linear guides, it is achieved that the lateral forces which occur are absorbed by them, and in particular that the double screw 4 and the threads of the wedge body which cooperate with it are relieved from such forces, or at least relieved.
[0046] The intervertebral implant 1 according to the invention is introduced and positioned in all embodiments essentially as follows.
[0047] First, access to the intervertebral body space is established as described in US Pat. No. 6,233,999.
[0048] The intervertebral implant 1 is then introduced through the access sleeve in its compressed state, corresponding to the configuration shown in FIG. 5. This then leads to the intermediate configuration shown in FIGS. 6 and 6a. Once the intervertebral implant 1 is positioned between two vertebrae, i.e., between the vertebra above and the vertebra below, a tool is inserted through the guide sleeve into the operating section to engage the proximal end of the intervertebral implant 1 and rotate the screw body 4 via the tool. Since the two double wedges 5, 5a cannot rotate together, they move away from each other in opposite directions from their starting position due to the threaded connection between them and the opposing external threads of the screw body. This can be seen in the transition from FIG. 2 to FIG. 3.
[0049] Here, the inclined bodies 5.2 and 5a.2 first engage with the corresponding opposing surfaces of the contact bodies 2.1-2.4, which then move laterally away from each other until the opposing surfaces of the contact bodies, e.g., 2.4.2, release the corresponding inclined surfaces, so that they can move along the support as the threaded body 4 rotates further. At the same time, i.e., after the support has completely moved laterally away, the inclined surface of the inclined body 5.1 engages with the corresponding opposing surface of the contact body, e.g., 2.6, so that as the threaded body rotates further, they are raised by these two surfaces until they reach the configuration shown in Figs. 7 and 7a.
[0050] In this last method step, the outer side of the contact body is run towards the vertebra, so that at least tension between the vertebra and the intervertebral implant is achieved. By having the contact body travel towards the vertebrae in an initially laterally expanded state, the risk of such damage can be significantly reduced or eliminated.
Claims
1. at least two upper and two lower contact bodies (2.1-2.4) with contact surfaces (2.1.1-2.4.1); a drive mechanism (3) comprising a screw body (4) provided with opposing threads (4.1, 4.2) arranged in series and having an extension axis (A); a wedge axially movably seated on the screw body (4) and movable along the screw body by rotation of the screw body, the wedge engaging at least opposing surfaces of at least a portion of the contact body and comprising inclined surfaces of an inclined body extending at a finite angle less than 90° to each other, The wedge is configured as a double wedge having a first inclined body and a second inclined body arranged side by side in the direction of the extension axis (A), the inclined surfaces (5.2.1, 5.2.2; 5a.2.1, 5a.2.2) of the first inclined body (5.2, 5a.2) and the inclined surfaces (5.1.1, 5.1.2; 5a.1.1, 5a.1.2) of the second inclined body (5.1, 5a.1) have different orientations, 1. An intervertebral implant, characterized in that the inclined surfaces (5.2.1, 5.2.2; 5a.2.1, 5a.2.2) of the first inclined body (5.2, 5a.2) directly engage with the contact body (2.1-2.4) laterally, while the inclined surfaces (5.1.1, 5.1.2; 5a.1.1, 5a.1.2) of the second inclined body (5.1, 5a.1) directly engage with the contact body (2.1-2.4) in the vertical direction.
2. 2. The intervertebral implant according to claim 1, characterized in that the inclined surfaces (5.2.1, 5.2.2; 5a.2.1, 5a.2.2) of the first inclined body (5.2, 5a.2) are oriented vertically with a horizontal surface normal (H), and the surface normal (F) of the inclined surfaces (5.1.1, 5.1.2; 5a.1.1, 5a.1.2) of the second inclined body (5.1, 5a.1) forms a finite angle (F) with the vertical (V) which is different from 90°.
3. An intervertebral implant as described in claim 1, characterized in that the opposing surfaces of the contact bodies (2.1-2.4) that cooperate with the inclined surfaces (5.1.1, 5.1.2, 5.2.1, 5.2.2; 5a.1.1, 5a.1.2, 5a.2.1, 5a.2.2) of the different inclined bodies face each of the inclined surfaces of the different inclined bodies and have a different spacing in the extension direction of the extension axis (A) of the screw body (4) of the drive mechanism compared to the spacing between the different inclined bodies (5.1, 5.2, 5a.1, 5a.2).
4. An intervertebral implant as described in claim 1, characterized in that the spacing between the inclined surfaces (5.1.1, 5.1.2, 5.2.1, 5.2.2; 5a.1.1, 5a.1.2, 5a.2.1, 5a.2.2) of the different inclined bodies is such that, relative to the spacing between the opposing surfaces of the contact bodies (2.1-2.4), the contact bodies (2.1-2, 4) move apart at least laterally when the screw body (4) is rotated, and then the upper and lower opposing contact bodies first move apart from each other.
5. The intervals between the inclined surfaces (5.1.1, 5.1.2, 5.2.1, 5.2.2; 5a.1.1, 5a.1.2, 5a.2.1, 5a.2.2) of the different inclined bodies are such that, relative to the intervals between the opposing surfaces, the contact body (2.1-2, 4) is first pressed against the opposing surface of the contact body (2.1-2.4) by the inclined surface (5.2.1, 5.2.2; 5a.2.1, 5a.2.2) of the first inclined body (5.2, 5a.2).
2. The intervertebral implant according to claim 1, characterized in that the inclined surfaces (5.1.1, 5.1.2; 5a.1.1, 5a.1.2) of the second inclined bodies (5.1, 5a.1) engage with the opposing surfaces of the contact bodies (2.1-2.4) in a disengaging manner only upon further rotation of the screw body (4) of the screw.
6. 2. The intervertebral implant according to claim 1, characterized in that the spacing between the inclined surfaces (5.1.1, 5.1.2, 5.2.1, 5.2.2; 5a.1.1, 5a.1.2, 5a.2.1, 5a.2.2) of the different inclined bodies of the double wedge (5 to 5a) is smaller than the spacing between the corresponding opposing surfaces.
7. 2. The intervertebral implant according to claim 1, characterized in that the driving mechanism comprises a radial disk or a radial wheel (4.3) rigidly connected to the screw body, the wheel engaging in slits (2.5) of the contact bodies (2.1-2.4) oriented radially with respect to the extension axis (A) of the screw body (4) for guiding the contact bodies perpendicular to the axis.
8. 2. The intervertebral implant according to claim 1, characterized in that guide rods (6.1, 6.2) which are in sliding engagement with at least the upper contact bodies (2.1, 2.2) are provided for relative guidance of the contact bodies (2.1, 2.2).
9. An intervertebral implant as described in claim 1, characterized in that the outer contact surfaces of the upper contact bodies (2.1, 2.2) form an angle of 5° to 15° with the outer contact surfaces of the lower contact bodies (2.3, 2.4).
10. 2. The intervertebral implant according to claim 1, characterized in that the ramps (5.1, 5.2, 5a.1, 5a.2) are configured in a double wedge and integral therewith.
11. 2. The intervertebral implant according to claim 1, characterized in that the overlapping and / or lateral contact bodies (2.1, 2.3; 2.2, 2.4 to 2.1, 2.2; 2.3, 2.4) are movably connected to one another via linear guides (7.1-7.4).
12. Intervertebral implant according to claim 11, characterized in that at least one linear guide is a tenon and mortise joint guide (7.3).
Citation Information
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