Vertebral column implant

Abstract

The invention relates to a vertebral column implant having a cage part and a plate-like part which is attached to one side of the cage part and, in a first state, is held so as to have a variable position in relation to the cage part and, in a second state, is fixed in a defined position, wherein the positional variability involves a pivotability in the lateral direction and a pivotability in the height direction, and the pivot axis Z for the pivotability in the lateral direction and / or the pivot axis X for the pivotability in the height direction run(s), in an orthogonal projection, closer to the side of the plate-like part facing away from the cage part than to the side of the plate-like part facing the cage part and / or a rotation-blocking element is provided which restricts a rotation of the plate-like part relative to the cage part about an axial axis Y extending predominantly, in particular completely, in the direction of the cross product of the Z and X directions of the two pivot axes.

Description

[0001] Linenweavers &

[0002] CARPENTER

[0003]

[0004] PATENT ATTORNEYS EUROPEAN PATENT ATTORNEYS EUROPEAN TRADEMARK ATTORNEYS EUROPEAN DESIGN ATTORNEYS

[0005] Patent Attorney Partnership mbB

[0006] Dipl.-Ing. H. Leinweber (1930-1976) Dipl.-Ing. H. Zimmermann (1962-2002) Dipl.-Phys. Dr. Jürgen Kraus

[0007] Dipl.-Ing. Thomas Busch

[0008] Dipl.-Phys. Dr. Patrick Werner Dipl.-Phys. Dr. Christina Kraus Viktualienmarkt 8

[0009] D-80331 Munich

[0010] TEL. +49-89-231124-0

[0011] FAX +49-89-231124-11 mail@leinweber-zimmermann.com Dat " f S. Feb. 2026

[0012] SIGNUS Medizintechnik GmbH

[0013] Industriestraße 2

[0014] 63755 Alzenau

[0015] SPINE IMPLANT

[0016] The invention relates to a spinal implant with a cage part and a plate-like part attached to one side of the cage part, which is held in a positionally changeable position relative to the cage part in a first state and fixed in a positionally fixed position in a second state, wherein the positional changeability includes pivotability in the lateral direction and pivotability in the vertical direction.

[0017] Implants with cages and plates are well-established in dental technology. Some such implants are based on a three-part structure with a spacer between the cage and the plate, as disclosed, for example, in WO 02 / 080819 A1. There are also one-piece versions in which the cage component and plate are connected in a single layer and are not repositionable relative to each other, as disclosed, for example, in DE 69734977 T2. WO 2012 / 021584 A2, in turn, discloses a three-component system with an additional spacer between the cage and the plate. WO 2011 / 028306 A1 discloses a system in which an anti-backout feature for the bone screws is formed by the head of a fixing element that holds the plate to the cage.

[0018] VAT Reg. No. DE 130758600. However, pivoting in more than one direction (polyaxial pivoting) between the plate and cage is often considered disadvantageous, and designs are instead implemented in which pivoting is limited to pivoting in only one plane, as taught, for example, in US 8,496,708 B2 or EP 2361 573 B1. The latter document discloses a movable connection in the form of a hinge joint. The pivot axis of such hinge joints lies between the plate and the cage.

[0019] All these spinal implants have their advantages and disadvantages. The invention is based on the objective of further developing a spinal implant of the type mentioned above in such a way as to achieve a satisfactory combination of simple implant design, moderate freedom of movement between its parts, and good handling during implantation.

[0020] The invention already presents a further development of a spinal implant of the type mentioned at the outset, which is essentially characterized in that a pivot axis Z for pivoting in the lateral direction and / or a pivot axis X for pivoting in the vertical direction runs in orthogonal projection closer to the side of the plate-like part facing away from the cage part than to the side of the plate-like part facing the cage part, and / or that a rotation lock is provided which restricts a rotation of the plate-like part relative to the cage part about an axial axis Y extending predominantly, in particular completely, in the direction of the cross product of the directions Z, X of the two pivot axes.

[0021] With the pivot axis positioned closer to the side of the plate-like part facing away from the cage component, even relatively small pivot angles are sufficient for a change in position. Furthermore, in the first state, there is an additional degree of freedom compared to hinge joint designs. The anti-rotation mechanism, on the other hand, ensures that while the positional change has two degrees of freedom, it occurs along defined directions that are essentially fixed in space and cannot change their position, as would be the case, for example, with a ball joint. In this respect, the spinal implant has a pivoting mechanism based on the principle of a universal joint.It is understood that, in order to realize the two position-changing parts in the first state, a certain amount of play must exist between a fixing element used to attach the plate-like part to the cage part and its guide within the plate-like part. This is the anti-rotation device.

[0022] Cylox18112024 should therefore be understood as no longer realizing the function of an (intended) additional degree of freedom of movement of a ball joint, but rather allowing the pivot axes of the two pivoting mechanisms to remain essentially fixed in space (i.e., except for marginal positional changes due to the aforementioned play) with respect to the cage part. In the first state, the parts are immobile with respect to translational movement.

[0023] The pivot axis can also be located beyond the side of the plate-like part facing away from the cage section. A preferred axial displacement factor is defined as the quotient of the difference in axial distance between the pivot axis and the axial position of the axial plate center and half the axial plate thickness, greater than 0.2, preferably greater than 0.4, and particularly greater than 0.6. However, this factor should not exceed 3.2, and particularly not greater than 2.6. This facilitates a satisfactory compromise between functional pivotability and the stability of the structures enabling this pivoting, as well as their ease of manufacture.

[0024] The plate-like part is preferably attached directly to the cage part, without the need for an intervening component. This reduces the complexity of the implant. In this context, it is preferably provided that the cage part and the plate-like part have complementary contact surfaces on their sides facing the other part. In the initial state, these surfaces can already be in contact with each other.

[0025] In another preferred embodiment, these contact surfaces are spherically shaped. The functional joint design, as a universal joint, thus exhibits a structural element of a ball joint, but without exhibiting a true ball joint action within the implant due to the anti-rotation feature. The pivot axes pass through the center of the sphericity.

[0026] In a further preferred embodiment, the contact surfaces are penetrated by an opening through which a fixing element, in particular a fixing screw, passes, holding the plate-like part to the cage part. Tightening this screw causes a transition from the first state to the second state. For this purpose, radial play is also provided between the fixing element and the rim of the opening in the plate-like part.

[0027] Regarding the implementation of the anti-rotation device, it is preferably provided that (at least) one of the parts has a projection extending into a recess of the other part. It is particularly preferred that the anti-rotation device

[0028] Cylox18112024 is arranged laterally on the outside and, in particular, is provided on both sides. This reduces translational forces in the event of stress on the anti-rotation device. Furthermore, torques can be introduced in the form of minimal forces when the anti-rotation device is stressed.

[0029] In this context, it is further preferred that the recess(es) be / are open laterally to the outside, and in particular be / are formed in a transverse groove-like manner (i.e., in the form of grooves extending in the lateral direction), especially in the cage part. This simplifies manufacturing and avoids a restriction of lateral pivoting at this point (the outside).

[0030] In a further preferred embodiment, a dimension of the projection extending in the vertical direction and / or its height tapers laterally from the inside out (taper angle α). This ensures a radial localization of the physical limit of the anti-rotation device and a stop to prevent pivoting.

[0031] In a preferred embodiment, the spinal implant is provided with a plurality of openings (22) for the passage of fastening screws, in particular two or four such openings, especially arranged in the four corner regions of the plate-like part.

[0032] In particular for a spinal implant with four screw holes, it is preferably provided that the plate-like part has a butterfly shape with respect to the lateral axis, in particular with a convex lateral curvature on its inner and / or outer side when viewed in the direction away from the cage part.

[0033] In particular, for a spinal implant with two such screw holes, the spinal implant preferably also has two passages in the cage part for the passage of fastening screws, one passage having a direction of passage towards the top of the cage and another passage having a direction of passage towards the bottom of the cage.

[0034] In a preferred embodiment, the outer edge of the spherical contact surface of the plate-like part, expressed as a percentage of 4TT, has a solid angle (with respect to the center of sphericity) of the area enclosed by its connection with the center greater than 3, preferably greater than 5.

[0035] Cylox18112024, in particular larger than 7 and / or smaller than 18, preferably smaller than 15, in particular smaller than 12. This favors a satisfactory compromise between functional pivotability and stability of the structures that effect this and their ease of manufacture.

[0036] In a further preferred embodiment, the ratio of the width (lateral dimension) of the cage part on its first side to the radius of sphericity of the contact surfaces is greater than 2, preferably greater than 2.4, particularly greater than 2.8, and / or less than 6, preferably less than 5.4, particularly less than 4.8. This also facilitates a satisfactory compromise between functional pivotability and stability of the structures that enable this pivoting, and their ease of manufacture.

[0037] In a further preferred embodiment, particularly for a spinal implant with four screw holes, the ratio of the product of the width of the cage part on its first side and the arithmetic mean of the two diagonal extensions of the plate-like part to the spherical surface area of ​​a sphere with the radius corresponding to the sphericity of the contact surfaces is greater than 3.6, preferably greater than 4.2, particularly greater than 4.8 and / or less than 8.4, preferably less than 7.8, particularly less than 7.2. This also facilitates a satisfactory compromise between functional pivotability and stability of the structures that enable this pivoting, and their ease of manufacture.For a spinal implant with two screw holes, it is provided that the ratio of the product of the width of the cage part on its first side and the arithmetic mean of the two diagonal extensions of the plate-like part to the spherical surface of a sphere with the radius of the sphericity of the contact surfaces is greater than 2.7, preferably greater than 3.1, in particular greater than 3.6 and / or less than 6.3, preferably less than 5.8, in particular less than 5.4.

[0038] In a further preferred embodiment, the pivotability in the lateral direction, measured as a swivel angle in degrees in both directions, is greater than 1.5, preferably greater than 2.5, and particularly greater than 3.5. This facilitates flexibility during implantation. Excessively large swivel angles for this axis are not necessary; 12 degrees on both sides or less is sufficient.

[0039] In a further preferred embodiment, the pivotability in the vertical direction, measured as a pivot angle in degrees in both directions, is greater than 2, preferably greater than 3.5, and particularly greater than 5. This facilitates flexibility during implantation. Excessively large pivot angles for this axis are not necessary; 18 degrees on both sides or less is sufficient.

[0040] Further features, details and advantages of the invention will become apparent from the following description with reference to the figures, of which

[0041] Fig. 1 shows a spinal implant in a perspective view,

[0042] Fig. 2 shows the plate-like part of the implant from Fig. 1 in a perspective rear view,

[0043] Fig. 3 shows the plate-like part of the implant from Fig. 1 in a top view of the back,

[0044] Fig. 4 shows the cage part of the implant shown in Fig. 1 in a longitudinal section view,

[0045] Fig. 5 shows the plate-like part in a diagonal sectional view,

[0046] Fig. 6 shows a cage part of a second embodiment in a front view, and

[0047] Fig. 7 shows a plate-like part of the second embodiment that matches the cage part from Fig. 6.

[0048] The spinal implant 100 shown in Fig. 1 is of the cage type and has a cage part 10. As is customary, the cage part 10 can have a structured surface on its upper and lower sides to adhere between two vertebrae in a known manner. The cage part 10 can have a non-zero lordosis angle L, preferably not greater than 16°, particularly not greater than 14°, and especially tending to be higher for larger nominal heights, down to zero for smaller nominal heights. The nominal height H of the cage part is preferably greater than 3 mm and not greater than 15 mm.

[0049] Furthermore, the spinal implant 100 has a plate-like part 20, hereinafter also referred to as plate 20, which has a central through-opening 27. The opening 27 is aligned

[0050] Cylox18112024 with a threaded opening 17 in the cage part 10, or hereinafter also referred to simply as cage 10, such that a (not shown) fixing screw can fix the plate 20 to the cage 10. The state in which the plate 20 is fixed to the cage 10 is referred to in this application as the second state. As long as the fixed state has not yet been reached because the fixing screw has not yet been tightened, the plate 20 can move relative to the cage 10 and is held in a positionally adjustable position relative to it. This state is referred to in the application as the first state.

[0051] As can best be seen by comparing Figures 2 and 4, the plate 20 has a spherically curved contact surface 28 on its rear side facing the cage, with a radius of curvature R (Fig. 5), which in this embodiment is 4.5 mm. This contact surface 28 rests against a complementary contact surface 18 (Fig. 4) of the cage 10. In the fixed position, the contact surfaces 28 and 18 are pressed together so tightly that the fixed position is ensured. In the first position, however, the contact surfaces 28 and 18, although already in contact, functionally form a ball joint due to their complementary shape and sphericity with the same radius R. Furthermore, the play of the fixing screw in the opening 27 is sufficiently large to avoid restricting a positionally adjustable mounting with respect to the three degrees of freedom of the ball joint.

[0052] Due to the projections 24, best seen in Fig. 2, arranged on both sides in a lateral direction and engaging in grooves 14 arranged on the front of the cage 10, the degree of rotational freedom of the ball joint 18, 28 for rotation about the axial axis Y is restricted and the functionality of the ball joint is reduced to that of a universal joint, which in the position-changeable first state allows the plate 20 to pivot relative to the cage 10 about a lateral pivot axis X, which passes through the center for the radius R of the ball joint 18, 28 and is perpendicular to the plane of the paper in Fig. 4, as well as pivotability about a vertical axis Z, which also passes through this center. In colloquial terms, the plate 20 can therefore tilt relative to the cage 10 in the up-down direction and in the left-right direction, but the positional relationship seen in projection orthogonal to the axial axis Y is maintained by the anti-rotation device 14, 24.

[0053] As can be seen from the diagonal section view in Fig. 5, the center for the ball joint 18, 28, relative to the axial direction Y, lies approximately at the level of the side of the plate 20 facing away from the cage 10, in any case significantly closer to this side than to the rear side of the plate 20 facing the cage 10. The first state with positional changeability is

[0054] Cylox18112024 is thus achieved without the hinge joints commonly used in engineering and has, in contrast to the hinge joint, the additional second degree of freedom of a universal joint.

[0055] The openings 23 visible to the left and right of the contact surface 28 in Fig. 3 serve to pivotally receive anti-backout parts 25 for securing (not shown) fixing screws, which, passing through openings 22, fasten the spinal implant 100 to the vertebral bodies in a known manner. The lateral distance XB from opposite sections of the outer edge U of the contact surface 28 is the same as the vertical distance of the same.

[0056] Figures 6 and 7 show a further embodiment of the invention. In this embodiment, the plate 20 no longer has four but only two fastening holes 22 for receiving the screws that secure the implant to the vertebrae. These fastening screws also penetrate the cage 10, which is provided for this purpose (Fig.

[0057] 6) also has two through holes 12, one of which is inclined downwards and the other inclined upwards. The central axis of the bore is inclined relative to the YZ plane, preferably with an angle of inclination in the range of 5° to 15°, in particular 8' to 12°, and also inclined relative to the XY plane, preferably with angles of inclination in the range of 32° to 56°, in particular 38° to 50°.

[0058] However, as can be seen by comparing Figures 3 and 7, the functionality of a ball joint provided by the contact surfaces 18, 28, which is reduced to a universal joint due to the anti-rotation device 14, 24, is the same as in the first embodiment shown in Figures 1 to 5.

[0059] In particular, the shape of the laterally external projections 24, which taper outwards, is the same in both embodiments, with a taper angle of 20° in this embodiment.

[0060] Furthermore, the invention is not limited to details of the examples shown. Rather, the individual features of the preceding description and the following claims can be essential, individually and in combination, for the realization of the invention in its various embodiments.

[0061] Cylox18112024

Claims

Claims 1. Spinal implant (100) with a cage part (10) and a plate-like part (20) attached to one side of the cage part, which is held in a positionally changeable position relative to the cage part in a first state and fixed in a positionally fixed position in a second state, wherein the positional changeability includes pivotability in the lateral direction and pivotability in the vertical direction, characterized by the fact that a pivot axis (Z) for pivoting in the lateral direction and / or pivot axis (X) for pivoting in the vertical direction in orthogonal projection runs closer to the side of the plate-like part facing away from the cage part than to the side of the plate-like part facing the cage part and / or that a rotation lock (14, 24) is provided which restricts a rotation of the plate-like part relative to the cage part about an axial axis (Y) running predominantly, in particular completely, in the direction of the cross product of the directions (Z, X) of the two pivot axes.

2. Spinal implant according to claim 1, wherein the cage part and the plate-like part have complementary contact surfaces (18, 28) on their side facing the other part.

3. Spinal implant according to claim 2, wherein the contact surfaces (18, 28) are spherically shaped.

4. Spinal implant according to claim 2 or 3, wherein the contact surfaces (18, 28) are penetrated by an opening (17, 27) through which a fixing element holding the plate-like part on the cage part passes, in particular a fixing screw, the tightening of which causes a transition from the first state to the second state.

5. Spinal implant according to one of the preceding claims, wherein the anti-rotation device has a projection (24) of one of the parts projecting into a recess (14) of the other of the parts. Cylox181120246. Spinal implant according to one of the preceding claims, wherein the anti-rotation device is arranged externally in a lateral direction, and in particular is provided on both sides.

7. Spinal implant according to claim 5 or 6, wherein the recess(s) (14) is / are open laterally outwards, and in particular is / are formed in a transverse groove shape, especially in the cage part (10).

8. Spinal implant according to one of claims 5 to 7, wherein a dimension of the projection extending in the vertical direction and / or its projection height tapers in the axial direction in a lateral direction from the inside to the outside.

9. Spinal implant according to one of the preceding claims, wherein the plate-like part has a butterfly-shaped form, in particular with a convex lateral curvature on its inner and / or outer side when viewed in the direction away from the cage part.

10. Spinal implant according to one of the preceding claims, comprising a plurality of openings (22) for the passage of fastening screws, in particular two or four such openings, in particular arranged in the four corner regions of the plate-like part.

11. Spinal implant according to one of the preceding claims, with at least two passages in the cage part serving for the passage of fastening screws, at least one passage having a direction of passage towards the top of the cage and at least one passage having a direction of passage towards the bottom of the cage.

12. Spinal implant according to one of claims 3 to 11, wherein the outer edge (U) of the spherical contact surface of the plate-like part, expressed as a percentage of 4TT, with respect to the center of sphericity of the area enclosed by its connection with the center, has a value greater than 3, preferably greater than 5, in particular greater than 7 and / or less than 18, preferably less than 15, in particular less than 12.

13. Spinal implant according to one of the preceding claims, wherein a ratio of the width (B) of the cage part at its first side to the radius of the Cylox18112024Sphericity of the contact surfaces is greater than 2, preferably greater than 2.4, in particular greater than 2.8 and / or less than 6, preferably less than 5.4, in particular less than 4.

8.

14. Spinal implant according to one of claims 3 to 13, wherein a ratio of the product of the width (B) of the cage part at its first side and the arithmetic mean of the two diagonal extensions of the plate-like part to the spherical surface of a sphere with the radius of the sphericity of the contact surfaces is greater than 3.6, preferably greater than 4.2, in particular greater than 4.8 and / or less than 8.4, preferably less than 7.8, in particular less than 7.

2.

15. Spinal implant according to one of the preceding claims, wherein the pivotability in the lateral direction as a pivot angle measured in degrees in both directions is greater than 1.5, preferably greater than 2.5, in particular greater than 3.

5.

16. Spinal implant according to one of the preceding claims, wherein the pivotability in the vertical direction as a pivot angle measured in degrees in both directions is greater than 2, preferably greater than 3.5, in particular greater than 5. Cylox18112024

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