WO2010037926A1

WO2010037926A1 - Intervertebral disc

Info

Publication number: WO2010037926A1
Application number: PCT/FR2009/001153
Authority: WO
Inventors: Hassan Razian
Original assignee: Hassan Razian
Priority date: 2008-10-02
Filing date: 2009-09-29
Publication date: 2010-04-08
Also published as: FR2936703A1; FR2936703B1

Abstract

The invention relates to intervertebral discs that can be placed between two vertebral bodies Cv1, Cv2. The disc of the invention is essentially characterised in that it comprises a plate (10) comprising a surface (11) contacting the vertebral body (Cv1) and an opposite surface (12), a blade (13) capable of assuming at least two positions (15, 16), a second plate (20) comprising a surface (21) contacting the vertebral body (Cv2) and an opposite surface (22), a blade (23) capable of assuming at least two positions (25, 26), and a means (30) mounted so as to engage with the two plates (10, 20) so that said two plates can pivot relative to each other about three different axes. The invention can be used in the field of intervertebral discs for replacing a damaged intervertebral disc.

Description

INTERVERTEBRAL DISC

The present invention relates to intervertebral discs adapted to be interposed between two consecutive vertebral bodies to replace a damaged intervertebral disc.

Numerous intervertebral disks implantable in the human body or the like are known, replacing the disc located between the two vertebral bodies of an intervertebral joint and damaged, for example, following an accident or an illness. These prostheses are, for the most part, essentially made of two parts respectively secured to the two vertebral bodies of the joint and movably mounted relative to each other, for example in the manner of a patellar movement, like those for example described and illustrated in WO 2007/127771 and WO 2007/113807. The problem that arises with this kind of prosthesis is the attachment of the two parts on the two vertebral bodies, mainly because of the very small dimensions of these prosthetic parts and the little free space between the two consecutive vertebral bodies between which must be implanted the replacement intervertebral disk. Thus, the present invention aims to provide an intervertebral disc which, while being of a simple embodiment, largely overcomes the aforementioned disadvantages of the discs of the prior art, allowing implantation much easier and more secure.

More specifically, the subject of the present invention is an intervertebral disk that can be interposed between two first and second consecutive vertebral bodies in replacement of a damaged intervertebral disk, as defined in claim 1 appended hereto.

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

Figure 1 is a block diagram of the structure of the intervertebral disc according to the invention, interposed between two vertebral bodies; Figure 2 is a schematic representation of a first embodiment of the intervertebral disc according to the invention in accordance with the block diagram of Figure 1;

FIGS. 3 and 4 show two orthogonal views of a second embodiment of the intervertebral disc according to the invention, FIG. 3 being a cross-sectional view of the disc interposed between two vertebral bodies, this section being referenced III-III on the Figure 4, and Figure 4 is a top view with the two vertebral bodies not shown.

It is first of all specified that, in the figures, the same references designate the same elements, whatever the figure on which they appear and whatever the form of representation of these elements.

The present invention relates to an intervertebral disk adapted to be interposed between two first and second consecutive vertebral bodies Cv1, Cv2, replacing an intervertebral disc damaged for any reason whatsoever.

More particularly with reference to FIG. 1, the intervertebral disk comprises a first plate 10 comprising a first face 11 adapted to come into contact with the first vertebral body Cv1 and a second face 12 opposite to the first face, a first blade 13 mounted in cooperation with this first plate, a second plate 20 having a first face 21 adapted to come into contact with the second vertebral body Cv2 and a second face 22 opposite to the first face, and a second blade 23 mounted in cooperation with the second plate.

The first blade 13 is mounted in cooperation with the first plate 10 so that it is able to take at least two first and second positions 15, 16.

The first position referenced 15 is that in which the first blade 13 is completely contained in the first half-space delimited by the plane passing substantially through the first face 11 of the first plate 10 and which contains the first plate 10. As for the second position 16 of the first blade 13, it is the one in which a first end 17 of this first blade emerges in the second half-space delimited by the plane passing substantially through the first face of the first plate and which does not contain this first plate.

The second blade 23 is mounted in cooperation with the second plate 20 so that it is able to take at least two first and second positions 25, 26.

The first referenced position 25 of this second blade 23 is that in which the second blade is entirely contained in the first half-space delimited by the plane passing substantially through the first face 21 of the second plate 20 and which contains the second plate. As for the second position 26, it is the one in which a first end 27 of the second blade 23 emerges in the second half-space delimited by the plane passing substantially through the first face of the second plate and which does not contain the second plate.

The intervertebral disk further comprises means, schematically illustrated at 30 in FIG. 1, mounted in cooperation with the first and second plates 10, 20 to allow these two plates to pivot relative to each other around three unmistakable axes, for example the three orthogonal traditional axes of space well known in physics. FIG. 2 schematically represents a first embodiment of these means 30 defined functionally above.

According to this embodiment, these means 30 are constituted by the fact that the two second faces 12, 22 of the two first and second plates 10, 20 are configured in respectively concave and convex spherical surfaces 31, 32 that are substantially congruent and pivotally mounted one to the other. in the other.

In this embodiment, the two blades 13, 23 are for example mounted in rotation independently of each other with respect to each plate 10, 20, respectively, about an axis which can be located on an edge of these plates. . However, this axis is advantageously located in housings opening on the respective first faces 11, 21 of the two plates, so that the first ends 17, 27 respectively of the two blades when they are in their second position 16, 26 are planted by cutting in the two vertebral bodies Cv1, Cv2.

The embodiment according to FIG. 2 in accordance with the block diagram according to FIG. 1, makes it possible to replace a damaged intervertebral disk and to restore the original relative movement between them of the two vertebral bodies. However, even if this embodiment achieves the goals set forth in the preamble of the present disclosure and has advantages over prior art disks, it does not yet provide all the benefits that practitioners can expect from such a disk. The second embodiment of the intervertebral disk according to the invention as illustrated in FIGS. 3 and 4, in agreement with the block diagram according to FIG. 1, has advantages over the first embodiment according to FIG.

In this second embodiment, the means 30 defined previously functionally, are constituted by the fact that the first and second blades 13, 23 are rotated relative to each other by their respective second ends 18, 28 opposite. at the first ends 17, 27, and that these two second ends are shaped respectively concave and convex spherical surfaces 41, 42 substantially congruent and mounted one in the other pivotally, the two blades 13, 23 being rotated substantially in their plane, between the second faces 12, 22 of the two plates 10, 20 and passing respectively through through-holes 45, 46 respectively formed in these two said plates. These means 30 further comprise, according to this second embodiment, means 50 for mounting the two plates 10, 20 in cooperation respectively with the two blades 13, 23 to, firstly support these two plates, and other away from each other when the two blades 13, 23 move from their first position 15, 25 to their second position 16, 26.

In Figure 3, the first position 15, 25 of the two blades is shown in broken lines, while the second position 16, 26 is shown in solid lines. In contrast, Figure 4 which is a view of above the disc in the same second embodiment, but without the vertebral bodies CvI ₁ Cv2, represents in continuous lines the two blades 13, 23 in their first position, and this, in order to better understand the structure of the disc in this second embodiment. In a particularly advantageous embodiment, the means 50 defined above for mounting the two plates 10, 20 in cooperation respectively with the two blades 13, 23, are constituted by two bearing surfaces 51, 52 integral respectively with the two blades and revolution about an axis substantially perpendicular to the plane of rotation of the two blades, and two complementary portions 53, 54 of the two bearing surfaces 51, 52 and made respectively on the two second faces 12, 22 respectively of the two plates 10, 20, the two blades being mounted in cooperation with the two plates so that the two bearing surfaces 51, 52 slide in rotation respectively on the two complementary parts 53, 54 when the two blades pass from their first position 15, 25 to their second position 16, 26, and vice versa.

The bearing surfaces 51, 52 may be of any kind, for example spherical. But, preferably, as illustrated, they will be cylindrical of revolution and convex. In addition, the means 50 for mounting the two plates 10, 20 in cooperation respectively with the two blades 13, 23 to support these two trays and away from one another when the two blades pass from their first position to their second position, are constituted so that the overall thickness Eβ of the bearing surfaces 51, 52 integral with the two blades, defined on a straight line perpendicular to the axis of rotation of the blades and to the straight line passing through the first ends 17, 27 of the two blades when the latter are substantially aligned, is less than the overall distance (D) between the two bearing surfaces 51, 52 defined on a straight line substantially parallel to the straight line passing through the first ends 17, 27 of the two blades when the latter are substantially aligned.

It is specified that, in the figures, each bearing surface 51, 52, associated with each blade consists of two half-bearing surfaces, a on each side of each blade. This embodiment being preferred so that the intervertebral disk is perfectly balanced, the realization with a single half-bearing surface is however technically possible.

Advantageously, when at least one of the plates 10, 20 is of a material having a non-zero creep coefficient, for example PEEK or the like, this plate further comprises reinforcing means 70, for example a lamella metal or the like, on at least the complementary portion 53, 54 made on its second face 12, 22. Only one of these lamellae has been shown, but it is obvious that each plate may comprise several of these lamellae. Similarly, although only one plate is shown with a reinforcement, both trays may both include such reinforcements.

Advantageously, for a safe purpose, the intervertebral disk may also comprise means 60 for limiting the rotation of the two blades 13, 23 relative to each other within defined limits, as well as means, represented schematically at 90, to limit the rotation and the distance of the two plates 10, 20 within specified limits.

These movement amplitude limitation means 60 and 90 are well known in themselves and will not be further described here for the sole purpose of simplifying the present description. As regards the means 60, one of their possible embodiments is illustrated in FIG. 4. As for the means 90, they may simply consist of a very loose interlocking between the two plates allowing both the rotations of the trays. and their distance from each other. These latter means are also in the field of those skilled in the art.

To facilitate its implantation, the intervertebral disk may also include means 80 for controlling simultaneously the passage, by rotation, of the two blades, one of its two positions 15-25, 16-26 to the other and vice versa . These means 80 are constituted by at least one of these three embodiments: at least one lug on each blade, at least one notch 81, 82 formed in each blade 13, 23, at least one notch in a blade and at least one ergot on the other. In addition, so Advantageously, the blades 13, 23 are configured to be able to cooperate with a fork with two teeth capable of pinching laterally the two blades at their second end 18, 28 and then having, in the bottom defined between its two teeth, a Complementary embodiment of that 81, 82 which is performed on the two blades 13, 23.

This second embodiment of the intervertebral disc according to the invention illustrated in FIGS. 3 and 4 is used and operates as follows:

When a Practitioner wants to implant a disc according to this second embodiment, in a known manner, prior to this implantation, it proceeds to the elimination of all the damaged disc, taking care to maintain the spacing between the two vertebral bodies by means of wedges arranged laterally.

It prepares a disc according to the invention, taking care to position the two blades so that they are both in their first position 15, 25, namely that shown in phantom in FIG. 3 and in continuous lines on the In this configuration, knowing that the thickness Ep is smaller than the distance D (FIG. 3), the two plates 10, 20 are in proximity to each other and the distance separating their first faces 11, 21 is minimal. In this way, the disc can easily be inserted between the two vertebral bodies Cv1, Cv2.

Then, by means for example of the fork defined above, it encloses the two blades 13, 23 so that the two lugs carried by the fork are respectively located in the notches 81, 82 made respectively in the two blades. It then makes this fork rotate 90 ° so that the first two ends 17, 27 of the two blades respectively traverse the through-holes 45, 46 made in the two plates 10, 20.

During this rotation, because of the structure of the disc defined above, on the one hand the two plates deviate from one another by a distance substantially equal to D - Ep, and secondly the first ends 17, 27 of the two blades are planted, by cutting, in the two vertebral bodies Cv1, Cv2. The first two faces 11, 21 of the two trays are then well pressed against the opposite faces of the two vertebral bodies, with more if necessary a distraction between the two vertebral bodies which relieves the patient optimally.

When the intervertebral disk is implanted between the two intervertebral bodies, that is to say in its configuration illustrated in FIG. 3, the two plates 10, 20 can pivot with respect to one another around the three axes. of the space defined above, as well as the two vertebral bodies Cv1 and Cv2 with respect to each other which regain their original relative mobility, essentially by the fact that: β the two blades 13, 23 are integral respectively of these two vertebral bodies, that

• the trays rest respectively on both the bearing surfaces of revolution 51, 52 and on the vertebral bodies, thereby forming two plate-blade pairs (10-13) and (20-23) integral, and that • the two blades can pivot by their second ends 18,

28 rotatably mounted by the respectively concave and convex spherical surfaces 41, 42.

In fact, the two vertebral bodies Cv1 and Cv2 pivot relative to each other by means of the respectively concave and convex spherical surfaces 41, 42 of the second ends of the blades, via the plates 10, 20 and the blades 13, 23 .

In the description above, it is clear that the disk according to the invention makes it possible to achieve all the goals defined in the preamble of this description.

Claims

An intervertebral disk adapted to be interposed between two first and second consecutive vertebral bodies (Cv1, Cv2) to replace a damaged intervertebral disc, comprising:

A first plate (10) comprising a first face (11) adapted to come into contact with the first vertebral body (Cv1) and a second face (12) opposite to the first face, • a first blade (13) mounted in cooperation with the first plate (10) so that said first blade is adapted to take at least two first and second positions (15, 16), said first position (15) being that in which said first blade (13) is entirely contained in the first half-space delimited by the plane passing substantially through the first face (11) of the first plate (10) and which contains the first plate (10), said second position (16) being that in which a first end (17) of said first blade (13) emerges in the second half-space delimited by the plane passing substantially through the first face (11) of the first plate (10) and which does not contain this first plate, • a second plate (20) comprising a first side (21) apt e to come into contact with the second vertebral body (Cv2) and a second face (22) opposite the first face,

A second blade (23) mounted in cooperation with the second plate so that said second blade is capable of taking at least two first and second positions (25, 26), said first position (25) being that in which said second blade (23) is entirely contained in the first half-space delimited by the plane passing substantially through the first face (21) of the second plate (20) and which contains this second plate, said second position (26) being that in which a first end (27) of said second blade (23) emerges in the second half-space delimited by the plane passing substantially through the first face (21) of the second plate (20) and which does not contain this second plate, and Means (30) mounted in cooperation with said two first and second plates (10, 20) to enable said two plates to pivot relative to one another about three non-coinciding axes, characterized by the that the means (30) mounted in cooperation with the first and second plates (10 ₁ 20) to enable said two plates to pivot relative to one another are constituted by the fact that the first and second blades (13, 23) are rotated relative to each other by their respective second ends (18, 28) opposite the first ends (17, 27), these two second ends being shaped respectively concave spherical surfaces and convex (41, 42) substantially congruent and mounted one in the other pivotally, the two blades (13, 23) being rotated substantially in their plane, between the second faces (12, 22) of the two trays ( 10, 20) and passing respectively years of through holes (45, 46) respectively formed in these two said plates, and they comprise means (50) for mounting the two plates (10, 20) in cooperation respectively with the two blades (13, 23) for supporting both said trays and moving away from each other when the two blades (13, 23) pass from their first position (15-25) to their second position (16-26).

2. Disk according to claim 1, characterized in that the means (50) for mounting the two plates (10, 20) in cooperation respectively with the two blades (13, 23) for supporting said two plates and move them away. one of the other when the two blades (13, 23) pass from their first position (15-25) to their second position (16-26) are constituted by two bearing surfaces (51, 52) respectively integral with the two blades (13, 23) and of revolution about an axis substantially perpendicular to the plane of rotation of the two blades, and two complementary parts (53, 54) of the two bearing surfaces (51, 52) made respectively on the two second faces (12, 22) respectively of the two plates (10, 20), the two blades being mounted in cooperation with the two plates so that the two bearing surfaces (51, 52) rotate respectively on the two additional parts (53, 54) when the two blades move from their first position (15-25) to their second position (16-26), and vice versa, the overall thickness (Ep) of the bearing surfaces (51, 52) defined on a straight line perpendicular to the axis of rotation of the blades and to the straight line passing through the first ends (17, 27) of the two blades when the latter are substantially aligned, being less than the overall distance (D) between the two surfaces of support (51, 52) defined on a line substantially parallel to the straight line passing through the first ends (17, 27) of the two blades when the latter are substantially aligned.

3. Disc according to claim 2, characterized in that, at least one of the trays being of a material having a non-zero creep coefficient, this plate comprises reinforcement means (70) on at least the complementary part ( 53, 54) made on its second face (12, 22).

4. Disc according to one of claims 1 to 3, characterized in that it comprises means (60) for limiting the rotation of the two blades (13, 23) relative to each other within limits determined.

5. Disc according to one of claims 1 to 4, characterized in that it comprises means (80) for simultaneously controlling the passage in rotation of said two blades, one of its two positions (15-25 16-26) to the other.

6. Disc according to claim 5, characterized in that the means (80) for simultaneously controlling the passage in rotation of said two blades (13, 23), from one of its two positions to the other, are constituted by at least one of these three embodiments: at least one lug on each blade, at least one notch (81, 82) formed in each blade (13, 23), at least one notch in a blade and at least one lug on the other.

7. Disc according to claim 6, characterized in that said blades (13, 23) are configured to be adapted to cooperate with a fork with two teeth capable of laterally gripping the two blades at their second end (18, 28), said fork having, in the bottom defined between its two teeth, an embodiment complementary to that (81, 82) which is formed on both said blades (13, 23).

8. Disc according to one of the preceding claims, characterized in that it comprises means (90) for limiting the rotation and removal of the two trays (10, 20) within specified limits.