A bladed cage suitable for implantation between two vertebrae

Abstract

The present invention relates to cages suitable for implantation between two vertebrae. The cage essentially comprises: an element 10 having two faces 11, 12, a lateral wall 13 and a cavity 20; locking means comprising two blades 31, 32; means for rotating the two blades and making them assume any position between a first position P1 and a second position, the first position P1 being that in which the blades are entirely contained within the space defined between the two planes passing through the faces 11, 12 and the second position being that in which one end of the blades emerges from this space, the two blades having a through-hole 41, 42 which also passes through the element 10, the hole 41 having an overall cross-section larger than the cross-section of the hole 42.

Description

Title of the invention: A blade cage suitable for implantation between two vertebrae Scope of the invention

[0001] The present invention relates to cages suitable for being interposed between two vertebrae in place of the intervertebral disc originally located between these two vertebrae.

[0002] Cages suitable for being interposed between two consecutive vertebrae in place of the intervertebral disc originally located between these two vertebrae are known, comprising: an element having the general shape of a disc, the element having two substantially parallel opposite faces suitable for coming into contact respectively with the two vertebral bodies, a lateral wall connecting the two opposite faces and a through cavity opening onto at least one of the two opposite faces, the cage further comprising means for locking said element with at least one of the two vertebral bodies, these locking means comprising at least a first blade and a second blade, and means for rotating the two blades so that they are suitable for assuming any position between a first position and a second position,The first position being that in which the blades are entirely contained within the cavity, and the second position being that in which at least one end of the blades emerges from this cavity to anchor itself in the bony portions.

[0003] The means for driving the two blades in rotation are generally made up of portions of rotation shaft which are respectively attached to the two blades and which are linked together, and means for driving one blade in rotation which drives the rotation of the other because the two portions of shaft are linked together.

[0004] As a result, the two tree portions linked together which pass through the cavity at least partially obstruct it, which can contribute to impairing the quality of the osteosynthesis between the two bone portions and thus weakening it.

[0005] In addition, these cages, which can give good results, nevertheless have a relatively complex structure, both when the planes in which the blades are mounted to rotate are parallel and when these planes make a non-zero angle between them, for example as in the cage described in FR2955483, and even more complex in this case.

[0006] Therefore, the present invention aims to provide an interbody cage whose structure is an improvement on the structure of the cage as defined above, and which finds a particularly advantageous, but not exclusive, application in the case of the cage according to this FR2955483 in which the two blades they form a non-zero angle with each other.

[0007] More specifically, the present invention relates to a cage suitable for interposing between two consecutive vertebrae in place of the intervertebral disc originally located between these two vertebrae, comprising: an element having the general shape of a disc, said element having two substantially parallel opposite faces, a lateral wall connecting the two said opposite faces, the two opposite faces being suitable for coming into contact respectively with the two vertebral bodies, and a through cavity opening onto at least one of the two opposite faces, said cage further comprising means for locking said element with at least one of the two vertebral bodies,these locking means comprising at least a first blade and a second blade whose overall width measured in a first plane perpendicular to the two said opposite faces is at most equal to the distance separating the two second parallel planes substantially coinciding respectively with these two said opposite faces and whose overall length measured in the first plane is greater than this distance, said cage further comprising means for rotating the two blades so that they are able to assume any position between a first position and a second position, the first position being that in which the blades are entirely contained within the space defined between the two second planes and the second position being that in which at least one end of the blades emerges from said space, characterized by the fact that said two blades have a through-hole also at least partially passing through said element,said openings being defined along a direction, the opening made in one of the two blades having an overall cross-section larger than the cross-section of the opening made in the other blade.

[0008] Other features and advantages of the invention will become apparent from the following description given opposite the drawing attached by way of illustration but in no way limiting, in which:

[0009] [Fig.1] The single figure represents a very schematic cross-sectional view of an embodiment of the interbody cage according to the invention.

[0010] It is first specified that the figure illustrates one embodiment of the object according to the invention, but that there may be other embodiments which meet the definition of this invention.

[0011] It is further 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 can be defined as comprising “at least one” of these elements.

[0012] It is also 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.

[0013] 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.

[0014] The present invention relates to an "interbody" cage and therefore includes certain means which are known in themselves. Thus, the description given below may be supplemented, if necessary, by the content of the description, for example, of FR2955483 or similar documents.

[0015] With reference to the single figure, the cage adapted to be interposed between two consecutive vertebrae in place of the intervertebral disc originally located between these two vertebrae comprises an element 10 made of a biologically compatible material such as titanium or PEEK, which has the general shape substantially of a disc. This element therefore has two substantially parallel (or similar) opposite faces 11, 12 adapted to come into contact respectively with the two vertebral bodies and a lateral wall 13 connecting the two opposite faces.

[0016] A through cavity 20 is made in this element 10 and opens onto at least one of the two opposite faces, very advantageously onto both faces.

[0017] The cage further comprises means for locking the element with the two vertebral bodies. These locking means comprise at least a first blade 31 and a second blade 32. The overall width of each blade, measured in a first plane perpendicular to the two opposite faces 11, 12, is at most equal to the distance separating the two parallel second planes substantially coinciding with these two opposite faces respectively, and the overall length of each blade, measured in the first plane, is greater than this distance.

[0018] The cage further includes means for rotating the two blades so that they are able to assume any position between a first position PI and a second position P2. In the first position PI, that illustrated in the single figure, the blades are entirely contained within the space defined between the two second planes defined above. As for the second position, it is that in which at least one end of the blades emerges from this space.

[0019] According to one feature of the invention, each blade 31, 32 has a through-hole 41, 42 also passing at least partially through the element 10. The two The cutouts 41, 42 are defined along a direction Dr and, in addition, the cutout 41 made in one 31 of the two blades has an overall section larger than the section of the cutout 42 made in the other blade 32.

[0020] Advantageously, the sections of the two openings 41, 42 are polygonal in shape. Even more advantageously, this polygonal shape is a hexagonal polygon, which is the most common shape for tools that allow the rotation of bodies of any kind, such as screws or the like.

[0021] Furthermore, according to a preferred embodiment, the means for rotating the two blades comprise at least one shaft 50 suitable for being inserted into the through bore having the largest cross-section, this shaft comprising two parts: a first part 51 called "distal" (the one furthest from the part of the shaft which is manipulated to introduce it into the bore) of a cross-section complementary to the cross-section of the bore having the smallest cross-section, and a second part 52 called "proximal" of a cross-section complementary to the cross-section of the bore having the largest cross-section.

[0022] The shaft 50 will therefore be introduced, according to the representation of the single figure, by first passing through the bore 41 made in the blade 31 so that the first part of shaft 51 then reaches the bore 42 in the blade 32.

[0023] According to another feature of the invention, the first distal part 51 of the shaft is slidably mounted in the second proximal part 52.

[0024] According to another feature of the invention, the first distal part 51 of the shaft 50 comprises ball joint means 53.

[0025] Advantageously, these ball joint means 53 are located on the portion of the first distal part 51 of the shaft which is able to cooperate with the opening 42 having the smallest cross-section.

[0026] In the case of a polygonal bore 42 of the "six-sided" type, the ball joint means 53 are constituted by the fact that the end of the shaft 50 plunging into this bore is shaped substantially into a hemisphere.

Claims

Claims

1. Intersomatic cage capable of being interposed between two consecutive vertebrae to replace the intervertebral disc originally located between these two vertebrae, comprising: an element (10) having the general shape of a disc, said element comprising two opposite faces (11, 12) substantially parallel, a lateral wall (13) connecting the two said opposite faces, the two opposite faces being capable of coming into contact respectively with the two vertebral bodies and a through cavity (20) opening onto at least one of the two opposite faces, said cage further comprising means for locking said element with at least one of the two vertebral bodies, these locking means comprising at least a first blade and a second blade (31,32) whose overall width measured in a first plane perpendicular to the two said opposite faces is at most equal to the distance separating the two second parallel planes substantially merged respectively with these two said opposite faces (11, 12) and whose overall length measured in the first plane is greater than this distance, said cage further comprising means for rotating the two blades so that they are able to take any position between a first position and a second position, the first position being that in which the blades are entirely contained in the space defined between the two second planes and the second position being that in which at least one end of the blades emerges from said space, characterized in that said two blades comprise a through-hole (41, 42) also at least partially passing through said element (10), said holes being defined in a direction (Dr),the opening (41) made in one of the two blades (31) having an overall section larger than the section of the opening (42) made in the other blade (32).,

2. Cage according to claim 1, characterized in that the sections of the two openings (41, 42) are of polygonal shape.

3. Cage according to claim 2, characterized in that the polygonal shape is a six-sided polygonal shape.

4. Cage according to one of claims 1 to 3, characterized in that the means for rotating the two blades comprise at least one shaft (50) which is inserted into the through-hole having the largest section, said shaft comprising two parts: a first part distal (51) of a section complementary to the section of the breakthrough having the smallest section, and a second proximal part (52) of a section complementary to the section of the breakthrough having the largest section.

5. Cage according to claim 4, characterized in that the first distal part (51) of said shaft is slidably mounted in the second proximal part (52).

6. Cage according to one of claims 4 and 5, characterized in that the first distal part (51) of said shaft (50) comprises ball joint means (53).

7. Cage according to claim 6, characterized in that said ball joint means (53) are located on the portion of the first distal part (51) of the shaft which is capable of cooperating with the opening (42) having the smallest section.

8. Cage according to one of the preceding claims, characterized in that the two blades (31, 32) are pivotally mounted respectively in two planes forming a non-zero angle between them.

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