Interbody cage suitable for lateral implantation

Abstract

The present invention relates to interbody cages suitable for lateral implantation between two vertebral bodies. The cage comprises an element 10 having two faces 11, 12 and a lateral wall 13 connecting these two faces; means for locking the element 10 to the two vertebral bodies consisting of a blade 23, a rotation shaft 20 capable of pivoting within the element 10 about an axis 21, means for mounting the blade 23 onto the shaft 20, a rotator 26, a gripper 27, means for cooperatively mounting the gripper 27 with the element 10 about an axis 28, this axis 28 forming a non-zero angle with the axis 21, and means for coupling the rotator 26 to the shaft 20 such that the rotation of the rotator 26 causes the rotation of the shaft 20. Figure 2

Description

Title of the invention: Interbody cage suitable for lateral implantation. Technical field

[0001] The present invention relates to interbody cages suitable for being interposed between two vertebrae in place of the intervertebral disc originally located between these two vertebrae, with the particular aim, according to the terminology commonly used by those skilled in the art, of performing arthrodesis with an interbody cage placed via an anterolateral or posterolateral approach.

[0002] More specifically, the present invention aims to produce an interbody cage suitable for lateral implantation which, compared to cages of the prior art, greatly facilitates the operative work of Practitioners and reduces the duration of the operation, while presenting a relatively simple and secure structure.

[0003] More specifically, the present invention relates to an interbody cage suitable for lateral implantation to be interposed between a first vertebral body and a second vertebral body in replacement of the intervertebral disc initially present between these two vertebral bodies, said cage comprising an element having the general shape substantially of a disc and having two substantially parallel opposite faces and a lateral wall connecting these two opposite faces, the two said opposite faces being suitable for coming into contact respectively with the two vertebral bodies, means for locking said element with the two vertebral bodies, these locking means being constituted by at least a first blade, a rotation shaft suitable for pivoting relative to said element along a first axis of rotation and means for mounting said blade on said rotation shaft,characterized in that the locking means further comprise a rotator having a substantially axial central channel along a second axis, said second axis making a non-zero angle with the first axis, a gripper, means for linking the gripper with said element, said gripper being mounted in cooperation with the rotator by passing through said central channel so that said rotator is able to pivot about the gripper, and coupling means between said rotator and said rotation shaft so that the rotation of the rotator correlatively causes the rotation of the rotation shaft and thereby the rotation of the blade.

[0004] Other features and advantages of the invention will become apparent from the following description given with reference to the accompanying drawings, which are by way of illustration but in no way limiting, in which:

[0005] Figure 1 shows an overview of an embodiment of the interbody cage according to the invention suitable for lateral implantation, and

[0006] [Fig.2] represents, in a transparent form, an embodiment of the part of the framed cage referenced Enc on [Fig.1].

[0007] It is specified that, when, according to the definition of the invention, the object of the invention comprises “at least one” element having a given function, the described embodiment may comprise several of these elements. Conversely, if the embodiment of the object according to the invention as illustrated comprises several elements with identical functions and if, in the description, it is not specified that the object according to this invention must necessarily comprise a particular number of these elements, the object of the invention may be defined as comprising “at least one” of these elements.

[0008] It is specified that when, in the present description, an expression defines by itself, without any particular specific mention concerning it, a set of structural characteristics, these characteristics may be taken, for the definition of the object of the protection sought, when this is technically possible, either separately, or in total and / or partial combination.

[0009] It is further specified that, in the present description, if the adverb "sensiblement" is associated with a qualifier of a given means, this qualifier must be understood in the strict or approximate sense.

[0010] With regard to the attached figures, the present invention relates to an interbody cage suitable for being interposed between two vertebral bodies in replacement of the intervertebral disc originally located between these two vertebral bodies.

[0011] The cage comprising an element 10 having the general shape substantially of a disc and having two substantially parallel opposite faces 11, 12 and a lateral wall 13 connecting the two opposite faces, these two opposite faces being able to come into contact respectively with the two vertebral bodies,

[0012] It includes means for locking the element 10 with the two vertebral bodies, these locking means comprising at least a first blade 23, a rotation shaft 20 capable of pivoting relative to the element 10 along a first axis of rotation 21 and means for mounting the blade 23 on the rotation shaft 20.

[0013] The means for mounting the blade 23 on the rotation shaft 20 are well known in themselves and a description of these can be found in FR2955483 and FR3136959.

[0014] According to one feature of the invention, the locking means further comprise: a rotator 26 having a substantially axial central channel about a second axis 28 making a non-zero angle with the first axis 21; a gripper 27 mounted in cooperation with the rotator by passing through the central channel 29 so that the rotator is able to pivot about the gripper; means for linking the gripper with element 10; and coupling means between the rotator 26 and the rotation shaft 20 so that the rotation of the rotator 26 causes corresponding rotation of the rotation shaft 20 and thereby the rotation of the blade 23.

[0015] The gripper 27 and the element 10 are thus perfectly joined to each other and the rotator 26 is well guided and supported in relation to the element 10, which makes it easier to operate as explained below for implanting the element 10 between two vertebrae.

[0016] Advantageously, [Fig.2], the means for linking the gripper 27 with the element 10 are constituted by the fact that an end 27-1 of the gripper is mounted by screwing 30 into the side wall 13 of the element 10.

[0017] According to a preferred embodiment, the coupling means between the rotator 26 and the rotation shaft 20 comprise a first gear 41 mounted axially on one end of the rotator 26, and more particularly ([Fig.2]) its axial part 26-1 at its end closest to the element 10, the axis of this first gear 41 being mounted coaxially with the second axis 28, a second gear 42 mounted coaxially with the first axis 21, and means for linking these first and second gears 41, 42 in rotation.

[0018] More specifically and advantageously, the means for linking the first and second gears 41, 42 in rotation comprise a third gear 43 mounted in rotation on a pivot shaft 45, and means for mounting this third gear in cooperation with the element 10 via the pivot shaft 45 along a third axis 44, this third gear being arranged to mesh with these first and second gears 41, 42.

[0019] This pivoting shaft 45 can advantageously have a crescent shape, or more generally a polygonal shape, for example a triangular one.

[0020] In an industrially advantageous way, the first and third axes 21, 44 are substantially parallel.

[0021] According to a preferred embodiment, the rotator 26 includes a guard cap 50 arranged to cover at least the first and third gears 41, 43 by defining a substantially bell-shaped volume 51 whose edge is substantially in contact with the side wall 13 of the element 10.

[0022] For example, this guard cap 50 is linked to the axial part 26-1 of the rotator 26, the one which supports the first gear 41, by means of a sleeve 26-2 which is screwed securely onto this axial part 26-1 with locking means at the end of travel such as a groove or similar illustrated schematically on [Fig.2].

[0023] Preferably, the cage comprises a safety screw 47 mounted in cooperation with the pivot shaft 45 such that the rotation of this pivot shaft causes the translation of this screw. Furthermore, this safety screw 47 is mounted in cooperation with the shaft 45 so that, at the end of the shaft's rotation, it is released from this shaft by partially plunging into the cavity 60 for the purpose which will be explained below.

[0024] Also, it is understood that, for the purposes of the present invention, by screw 47, it is understood that any oblong body capable of undergoing at least one translation along the axis 44 as a function of the rotation of the shaft 45, in particular via means which transform a rotational movement into a translational movement.

[0025] According to a preferred embodiment, the element 10 has a substantially central cavity 60 opening onto the two opposite faces 11, 12, the rotation shaft 20 being located at least partly in this cavity by passing through it and emerging from it on the lateral wall 13, the second gear 42 being fixed to this rotation shaft 20 by being substantially supported on the lateral wall 13. The first 41 and third 43 gears are also, for example, mounted substantially supported on this lateral wall 13.

[0026] According to another preferred embodiment, the cage includes a second blade ([Fig.2]) and means for mounting this second blade on the rotation shaft 20, the first and second blades being mounted on the part of the rotation shaft located in the cavity 60, these two blades also making a non-zero angle between them, very advantageously.

[0027] The cage according to the invention described above can be used in the following manner.

[0028] Initially, the cage has a configuration like the one illustrated on the [Fig.2], namely with the blade 23 (the two blades) entirely contained in the cavity 60, the end 27-1 of the gripper 27 screwed in 30 into the wall of the element 10, the guard cap 50 of the rotator 26 covering the gears 41 and 43, the gear 43 being meshed with the other two gears 41 and 42.

[0029] The cage is then introduced between the two vertebral bodies, in a known manner via the lateral route, using the gripper 27 to implant the element 10 between the two vertebral bodies, making it take the final position determined by the Practitioner.

[0030] When the Practitioner has judged that the element 10 is correctly positioned between the two vertebral bodies, he turns the rotator 26, which causes the rotation of the gear 41 without causing a rotation of the gripper 27, then the rotation of the gear 43 which in turn causes the gear 42 which is fixed to the shaft 20 to undergo the same rotation.

[0031] In the rotation of the shaft 20, the blade 23 (or the two blades) pivot(s) and emerge(s) from the cavity 20 to implant themselves in the bone of the vertebral body of the two vertebrae and thus secure the element 10 with at least one of the two vertebral bodies, generally both vertebral bodies as in the realizations of cages of the prior art.

[0032] In addition, the rotation of the gear 43 causes the pivot shaft 45 to rotate, and therefore the safety screw 47 which is set to partially emerge from the inner wall of the cage 10, after the blades have totally emerged from the space 60. By emerging into the cavity 60, the screw constitutes a safety stop which prevents an unintentional reverse rotation of the blade 23 (or both).

[0033] After the implantation of the blade 23, or both, the gripper 27 and the rotator 26 are removed including the two gears 41 and 43 which are held in the guard cap 50, for example by pinning on a shaft integral with the inner wall of this cap, which prevents these gears from being lost in the operating site.

[0034] From the description given above, the advantages of the cage according to the invention appear compared to the cages of the prior art which can have a similar result, namely implantation by lateral route.

Claims

Demands

1. An interbody cage adapted to be implanted laterally for interposition between a first vertebral body and a second vertebral body in replacement of the intervertebral disc initially present between these two vertebral bodies, said cage comprising: • an element (10) having the general shape substantially of a disc and having two substantially parallel opposite faces (11, 12) and a lateral wall (13) connecting these two opposite faces, the two said opposite faces being adapted to come into contact respectively with the two vertebral bodies, and • means for locking said element (10) with the two vertebral bodies, these locking means being constituted by at least a first blade (23), a rotation shaft (20) adapted to pivot relative to said element (10) about a first axis of rotation (21) and means for mounting said blade (23) on said rotation shaft (20),characterized in that the locking means further comprise a rotator (26) having a substantially axial central channel along a second axis (28), said second axis (28) making a non-zero angle with the first axis (21), a gripper (27), means for linking the gripper with said element (10), said gripper being mounted in cooperation with the rotator by passing through said central channel (29) so that said rotator is able to pivot around the gripper, and coupling means between said rotator (26) and said rotation shaft (20) so that the rotation of the rotator (26) correlatively causes the rotation of the rotation shaft (20) and thereby the rotation of the blade (23).

2. Cage according to claim 1, characterized in that said coupling means between the rotator (26) and the rotation shaft (20) comprise a first gear (41) mounted axially on one end of the rotator (26), the axis of this first gear (41) being mounted coaxially with the second axis (28), a second gear (42) mounted coaxially with said first axis (21), and means for linking in rotation these first and second gears (41, 42).

3. Cage according to claim 2, characterized in that the means for rotationally linking the first and second gears (41, 42) comprise a third gear (43) rotatably mounted on a pivot shaft (45), and means for mounting this third gear in cooperation with said element (10) via the pivot shaft (45) along a third axis (44), this third gear being arranged to mesh with said first and second gears (41, 42).

4. Cage according to claim 3, characterized in that said first and third axes (21, 44) are substantially parallel.

5. Cage according to any one of claims 3 and 4, characterized in that the rotator (26) has a guard cap (50) defining a substantially bell-shaped volume (51) the edge of which is substantially in contact with the side wall (13) of the element (10) covering at least the first and third gears (41, 43).

6. Cage according to any one of claims 3 to 5, characterized in that it comprises a safety screw (47) mounted in cooperation with the pivot shaft (45) so that the rotation of this pivot shaft causes the translation of the screw.

7. Cage according to claim 6, characterized in that the safety screw (47) is mounted in cooperation with the pivot shaft (45) so that, at the end of rotation of the shaft, it is released from this shaft.

8. Cage according to any one of the preceding claims when it depends on claim 3, characterized in that said element comprises a cavity (60) opening onto the two opposite faces (11, 12), said rotation shaft (20) being located at least partly in said cavity and emerging from it on said side wall (13), the second gear (42) being integral with this rotation shaft (20) by being substantially supported on the side wall (13).

9. Cage according to claim 8, characterized in that said cage comprises a second blade and means for mounting said second blade on said rotation shaft (20), the first and second blades being mounted on the part of said rotation shaft located in said cavity (60), these two blades optionally forming a non-zero angle with each other.

10. Cage according to any one of the preceding claims, characterized in that the means for linking the gripper (27) with the element (10) are constituted by the fact that one end (27-1) of said gripper (27) is mounted by screwing (30) into the side wall (13) of said element.