Intervertebral cage

Abstract

The present invention relates to intersomatic cages. The intersomatic cage, capable of being positioned between two vertebrae V1, V2, comprises an element (10) having the general shape of a disk that defines two opposite faces (11, 12) capable of coming respectively into contact with the two vertebrae, means serving to block the element on a single vertebra V1 and consisting of a first half-blade (31) and a second half-blade (32), each defined in a plane, means for rotating these two half-blades with respect to the element via a rotation shaft (48) with axis of rotation (100), and means for fixing each half-blade on a same side of the rotation shaft (48) opposite each other and so that their planes form between them an angle different from a zero angle.

Description

Intervertebral cage

[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.

[0002] The design of known interbody cages incorporates mechanisms that lock them in place immediately upon implantation between two vertebrae. However, this design sometimes presents drawbacks for the successful resolution of the patient's problem, particularly for the proper creation of the osteosynthesis between the two vertebrae.

[0003] The present invention therefore aims to produce a new interbody cage which makes it possible to overcome at least in part these disadvantages of the anterior interbody cages, to improve the quality of the osteosynthesis between the two vertebrae, while having a very simple structure, not posing any difficulties for its implantation and even facilitating the work of the practicing surgeon.

[0004] More specifically, the present invention aims to provide an interbody cage suitable for interposing between two vertebral bodies in place of the intervertebral disc originally located between the two vertebrae, comprising an element having the general shape of a disc defining two opposite faces suitable for coming into contact with the two vertebrae respectively, characterized in that it further comprises means for locking said element with a single vertebra, these means being constituted by a first half-blade and a second half-blade, each being defined substantially in a plane, means for rotating said two half-blades relative to said element via a rotation shaft which is defined along an axis of rotation, and means for fixing each half-blade on the same side of said rotation shaft substantially opposite each other and in such a way that their planes make an angle other than zero.

[0005] Other features and advantages of the invention will become apparent from the following description given in relation to the accompanying drawings, which are by way of illustration but in no way limiting, in which:

[0006] Figure 1 represents a top view of a preferred embodiment of the interbody cage according to the invention, in which the two half-blades are in a "retracted" position, and

[0007] Figure 1 represents a side view along arrow Fl, of the embodiment of the interbody cage according to the invention according to the figure, in which the two half-blades are in the "exit / emergent" position.

[0008] 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 the description does not specify 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.

[0009] It is specified that when, in this 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.

[0010] 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.

[0011] It is further specified that, for the purposes of the invention, the term "half-blade" used in the present description is defined, for greater understanding, in relation to the well-known blades of prior art cages which are one-piece blades linked to a rotation shaft by having two portions located respectively on either side of this rotation shaft, so that these two portions are able to be implanted respectively in the two vertebral bodies of two consecutive V1 and V2 vertebrae.

[0012] The term "half-blade" used in this description refers to only one of these portions so that it is implanted in only one of the two vertebrae.

[0013] The structure of such a half-blade, as defined, is perfectly apparent from the drawings attached to this description.

[0014] Figures 1 and 2 represent a preferred embodiment of the interbody cage according to the invention.

[0015] This intersomatic cage is suitable for being interposed between two vertebrae V1, V2 in replacement of the intervertebral disc originally located between them, comprising an element 10 having the general shape of a disc defining two opposite faces 11, 12 suitable for coming into contact with the two vertebrae respectively.

[0016] The cage according to the invention further includes means for locking the element 10 with a single V1 of the two vertebrae V1, V2.

[0017] These locking means comprise a first half-blade 31 and a second half-blade 32, each being defined substantially in a plane, means for driving these two half-blades in rotation relative to the element 10 via a rotation shaft 48 defined along a rotation axis 100, and means for fixing each half-blade 31, 32 on the same side of this rotation shaft 48, namely offset from it, so that these two half-blades are substantially opposite each other and that their planes make an angle with each other other than zero, the value of this non-zero angle being, for example, advantageously substantially on the order of twenty degrees.

[0018] Thus the two half-blades 31, 32 are in one of the following two positions: divergent position (as illustrated in the figures) namely with their free ends far apart from each other; convergent position (not illustrated), namely with their free ends close together.

[0019] Advantageously, at least one of the half-blades has a substantially spoon-like shape, for example slightly concave.

[0020] More preferably, the element 10 has a substantially central opening to form a cavity 14 open on opposite faces 11, 12. In this case, the half-blades 31, 32 are arranged according to one of the following three possibilities: both in the cavity, both outside the cavity, one in the cavity and the other outside the cavity.

[0021] As for the means mentioned above for fixing the half-blades 31, 32 to the shaft 48, they are known in themselves. Very schematically, for example: the half-blades have, at one end, axial bores with a cylindrical polygonal cross-section and are positioned on the shaft, which has a complementary cross-section, to be inserted into these bores. The blades are then secured to the shaft by any means, for example by a pin, a nut, etc.

[0022] Element 10 can be made of titanium or PEEK (i.e., polyetheretherketone) or a similar material. As for the half-blades and the shaft, they are, for example, made of titanium or stainless steel or a similar material.

[0023] From the description given above, it is readily apparent that the cage according to the invention fulfills the purpose of the present invention as defined in the preamble.

[0024] In particular: referring more specifically to the, we observe that the two half-blades 31 and 32 make a non-zero angle with each other (divergent position as illustrated) and that, as a result, when they are implanted in the bony body of a vertebra, preferably a superior vertebra V1, they ensure, by wedge effect known in itself, a firm connection of solidarity of the disc 10 with this vertebra V1.

[0025] On the other hand, the vertebral body of vertebra V2 is simply in contact with face 12 of element 10, which allows a slight spatial translation in 3D, mainly in 2D, of this element 10 relative to vertebra V2, allowing it to automatically take a position that is the least traumatic possible for the patient.

Claims

An interbody cage suitable for interposition between two vertebrae (V1, V2) in place of the intervertebral disc originally located between the two vertebrae, comprising an element (10) having the general shape of a disc defining two opposite faces (11, 12) suitable for coming into contact with the two vertebrae respectively, characterized in that it further comprises means for locking said element (10) with a single vertebra (V1), these means being constituted by: • a first half-blade (31) and a second half-blade (32), each being defined substantially in a plane, • means for rotating said two half-blades relative to said element via a rotation shaft (48) defined along an axis of rotation (100), and • means for fixing each half-blade (31, 32) on the same side of said rotation shaft (48), namely offset from it.positioned approximately opposite each other, and such that their planes form an angle other than zero. Cage according to claim 1, characterized in that the value of said non-zero angle is substantially on the order of twenty degrees of angle. Cage according to one of the preceding claims, characterized in that the two half-blades (31, 32) are in one of the following two positions: convergent position, divergent position. Cage according to one of the preceding claims, characterized in that at least one of the two half-blades has substantially a spoon shape. Cage according to any one of the preceding claims, said element having a substantially central opening to form a cavity (14) open on said opposite faces (11, 12), characterized in that the first and second half-blades (31, 32) are arranged according to one of the following three possibilities: both in the cavity, both outside the cavity, one in the cavity and the other outside the cavity.

Images