FR2930426A1 - Intersomatic cage for use between vertebrae, has coupling unit coupling strips so that strips takes position between two positions in which strips are entirely held in through bore and each of strips emerges from bore, respectively - Google Patents

Abstract

The cage has a body (10) in the form of a cylinder (11), comprising a through bore (20) formed along an axle (21). A blocking unit of the body has strips (31, 32) whose overall width and length are equal to and greater than a height of the bore. A coupling unit (34) rotatively couples the strips so that the strips are respectively supported on opposed portions (36, 37) of an inner wall (38) of the bore and takes a position between two positions. The strips are entirely held in the bore in one of the positions and a portion of each of the strips emerges from the bore in another position.

Description

/ 04/2008 15:22 0160831607 ABRITT POrr R1 INTERSOMATIC CAGE

The present invention relates to intersomatic cages adapted to be interposed between two vertebrae in replacement of an intervertebral disk, of the type comprising a body of generally cylindrical general shape and means for blocking the body with at least one of the two vertebrae by means of of a blade. Indeed, it is known cages which comprise a body of generally cylindrical general shape and means for locking the body with at least one of the two vertebrae between which the body has been put in place, by means of a blade which is able to pivot relative to the body so that its ends are planted in the bone of the vertebrae. Such an embodiment is for example described and illustrated in EP-A-1567097 in the name of the Applicant.

This achievement gives good results, but technicians have constantly tried to improve. In this context, the present invention aims to achieve an interbody cage that gives even better results than those of the prior art, including allowing a better anchoring in the vertebrae and more secure, while facilitating the work of practitioners. More specifically, the present invention relates to an intersomatic cage adapted to be interposed between two vertebrae in replacement of an intervertebral disc, said intersomatic cage comprising a generally cylindrical body of generally having a substantially central through-hole formed along a substantially parallel axis the generatrix of the cylindrical shape, and locking means of said body with at least one of the two vertebrae, characterized in that the locking means are constituted by at least: • two first and second blades whose overall width is at most equal to the height of said through-hole and the overall length is greater than the height of this through-hole; means for rotatably coupling the first and second blades so that they are respectively resting on two first and second opposite portions of the inner wall of said pierced e through and able to take any position between two first and second positions, the first position being one in which the two blades are entirely contained in said through-hole and the second position being that in which at least a portion of each blade emerges from said through breakthrough. Other features and advantages of the invention will become apparent from the following description given with reference to the accompanying drawings, which are illustrative but in no way limiting, in which: FIG. 1 represents a schematic sectional view of an embodiment of FIG. the intersomatic cage according to the invention, and FIGS. 2 and 3 respectively represent two alternative embodiments of a part of the intersomatic cage according to the invention in accordance with the embodiment according to FIG. 1. It is all of firstly, 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. Likewise, if elements are not specifically referenced in one of the figures, their references can be easily found by referring to another figure. It is also pointed out that the figures essentially represent three embodiments of the object according to the invention, but that there may be other embodiments that meet the definition of this invention. It is furthermore 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 embodiment described may comprise several of these elements. Conversely, if the embodiment of the object according to the invention as illustrated has several elements of identical function and if, in the description, it is not specified that the object according to this invention must obligatorily comprise a number particular of these elements, the object

of the invention may be defined as comprising "at least one" of these elements. Lastly, it is specified that when, in the present description, an expression defines, by itself, without a specific particular mention concerning it, a set of structural characteristics, these characteristics may be taken, for the definition of the object of the protection requested, when technically possible, either separately, or in full and / or partial combination. The intervertebral cage according to the invention is able to be interposed between two vertebrae to replace an intervertebral disc for any reason whatsoever, following an accident, a disease, etc. The intervertebral cage, more particularly with reference to FIG. 1, comprises a body 10, for example but not exclusively made of PEEK (in English "PolyEthylEtherKetone" - in French "poly (ether-ether-ketone)"), of general shape substantially cylindrical 11 or similar in the form of a disk or the like and having a substantially central through-hole 20 formed along an axis 21 advantageously substantially parallel to the generatrix of the cylindrical shape, and means for locking the body 10 with at least 1 one of the two vertebrae, of course and advantageously with both. According to an essential characteristic of the invention, the locking means are constituted by at least two first and second blades 31, 32 whose overall width, taken parallel to the direction of the axis 21 in the configuration of FIG. is at most equal to the height of the through-hole 20, that is to say to the thickness of the body 10, and the overall length is greater than the height of this same through-hole, for the purpose which will be defined below and that is the same as for cages that have only one blade. These means for blocking the body 10 with at least one of the vertebrae further comprise means 34 for coupling in rotation the first and second blades 31, 32 so that they respectively bear, directly or indirectly, on two first and second opposite portions 36, 37, preferably planar as illustrated in the three figures, of the inner wall 38 of the through-hole 20, and furthermore they are able to take any position between two first and second positions. The first position is that in which the two blades are entirely contained in the through-hole, which is the position shown in FIG. 1, and the second position is that in which at least a portion of each blade emerges from the through-hole, and advantageously both ends of the two blades, to obtain an anchoring in the two bony bodies of the two vertebrae between which the cage must be interposed.

According to a preferred embodiment, the coupling means 34 defined above for rotatingly coupling the first and second blades 31, 32 are constituted, as in the illustrated embodiment, by a shaft 40, for example made of metal or the like, which is substantially perpendicular to the axis 21 of the through-hole 20. This shaft comprises two first and second ends 48, 49, advantageously of cylindrical shape of rotation, respectively rotatably mounted in two first and second bearings 41, 42 made in the body 10 respectively opening on the first and second opposite wall portions 36, 37 of the inner wall 38 of the through-hole 20. These bearings will generally be simply through orifices each having a section complementary to that of the end of the tree with which he will have to cooperate. These means 34 for coupling in rotation of the first and second blades 31, 32 further comprise means for respectively mounting the two blades on the shaft 40 so that they are locked in rotation and in translation relative to this shaft when they bear respectively on the first and second opposite wall portions 36, 37 of the inner wall 38 of the through-hole. Advantageously, these means for mounting the two blades 31, 32 on the shaft 40 are formed by two first and second orifices 43, 44 respectively formed in the first and second blades 31, 32, the shaft 40 having two first and second sections. 45, 46 able to cooperate by plugging with respectively these first and second orifices and a shoulder 50 of an overall cross section greater than the overall section of the second orifice 44 and at most equal to the overall section of the first port 43, this shoulder being formed on the shaft 40 so that when the second end 49 of the shaft is rotatably mounted in the second bearing 42 and the second blade 32 is mounted on the second section 46 of the 40 and bears against the second portion 37 of the inner wall of the through-hole 20, this shoulder 50 is in contact with the second blade 32, the latter being located between the shoulder 50 and the second xtremity 49 of the shaft 40.

In addition, these blade mounting means also comprise means 60 for locking the first blade 31 so that, when this first blade 31 is mounted on the first section 45 of the shaft and the two ends 48, 49 of the shaft 40 are respectively rotatably mounted in the first and second bearings 41, 42, the first blade bears against the first portion 36 of the inner wall 38 of the through-hole 20. According to possibilities that are advantageous, these means 60 for block the first blade 31 are constituted by at least one of the three means described below.

According to a first embodiment illustrated in Figure 1, these locking means 60 of the first blade 31 are constituted by a hole 63 formed transversely in the shaft 40 and a pin adapted to cooperate with the hole 63, to take the first blade 31 sandwiched between it and the first portion 36 of the inner wall 38 of the through-hole.

According to a second embodiment illustrated in FIG. 2, these locking means 60 of the first blade 31 are constituted by a length of the first section 45 of the shaft 40 greater than the thickness of the first blade 31, and a thread 61 made on the first section 45 of the shaft 40 and a nut 62 adapted to be screwed on this first section 45 to take the first blade 31 sandwiched between it 62 and the first portion 36 of the inner wall 38 of the through-hole. In the case of the two embodiments described above, it is advantageous for the orifices 43, 44 to be of polygonal shape, and

the same is therefore true for the first and second corresponding sections 45, 46 of the shaft 40. In the case of the third possible embodiment illustrated in FIG. 3, the blocking means 60 are constituted by a length of the first section 45 of the shaft 40 greater than the shoulder of the first blade 31, a thread 61 formed on the first section 45 of the shaft 40 and a tapping of the first hole 43 made in the first blade 31, this thread being complementary to the thread carried by the first section 45 of the shaft so as to allow the first blade 31 to come into contact with the first portion 36 of the inner wall 38 of the through-hole when it is screwed onto this first section 45. illustrated in Figure 1, the cage may advantageously further comprise at least one auxiliary blade, preferably two 71, 72 as illustrated. This auxiliary blade 71, 72 is advantageously mounted in rotation relative to the body 10 in the through hole 20 in a plane substantially perpendicular to the planes passing through the first and second blades 31, 32, so that it is able to take any position between two positions, one being the one in which it is entirely contained in the through-breakthrough and the other being the one in which it emerges from the through breakthrough. Of course, the cage then comprises means for controlling the rotation of the auxiliary blade 71, 72. In an advantageous embodiment to facilitate the work of practitioners during the implantation of the intervertebral cage, the means for controlling the rotation of the blade 71, 72 are constituted by one of the first and second blades 31, 32 which is arranged so that when it is controlled in rotation by means of the shaft 40, it rotates the auxiliary blade 71, 72 Such an embodiment is for example as illustrated (Figure 1), where the ends of the first blade 31, when in its first position, are respectively above and below an end respectively of the two auxiliary blades 71 , 72. Thus, when the blade 31 is rotated by means of the shaft 40, it causes in its movement the rotation of the two auxiliary blades, respectively in direction 7

reverse in relation to each other, so that they emerge from the piercing breakthrough and become anchored in vertebral bodies. Preferably, the cage further comprises specific means 80 for controlling the rotation of the shaft 40 to pass the first and second blades 31, 32 from one of their first and second positions to the other. These means 80 for controlling the rotation of the shaft 40 consist for example of an open recess housing 81 made in one of the ends 48, 49 of the shaft 40, for example a six-sided housing or the like, in which is capable of cooperating an ancillary such as a screwdriver or the like of the same type, that is to say the six-sided type. In order to be able to maintain the cage more easily, for example when it is implanted between two vertebrae, the cage advantageously comprises, in addition, a threaded cavity made in the shaft and able to cooperate with an ancillary end bearing a thread complementary to that of the cavity. According to possible embodiments, this threaded cavity is at least one of the following forms: (i) made (90) in the bottom of the recessed housing 81 (FIG. 1), (ii) constituted by the hollow recess -Even 81 which in this case will bear, on its side wall, the tapping of the cavity.

With the embodiment according to FIG. 1, the cage comprises four anchoring points perfectly distributed at the periphery of the body 10, which gives it perfect anchoring safety, since it is held along two perpendicular axes defined by the rotation axes respectively of the first and second blades 31, 32 and the two auxiliary blades 71, 72, thereby eliminating any risk of sliding of the cage between the two vertebral bodies. Another important advantage of the structure of the cage as described above is the fact that the through-hole 20 has a large volume which makes it possible to receive a large quantity of bone grafts, which favors a better osteosynthesis between the two vertebral bodies. . An interbody cage according to the invention can be easily mounted as follows:

The two blades 31, 32 are introduced into the through-hole 20 so that their orifices 43, 44 are substantially aligned with the bearings 41, 42. Then the shaft 40 is introduced into the body by passing its second end 49 in the first bearing. 41 and, successively, in the orifices 43, 44 of the two blades until its second end 49 is positioned in the second bearing 42. Due to the shoulder 50, the second blade is pressed against the second wall portion 37. The first blade 31 is then slid on the shaft 40 until it is pressed against the first wall portion 36. In the case of the structure according to FIG. 1, a pin is then inserted into the hole 63 to block the first blade and, consequently, all the elements in the body 10. When they exist, the two auxiliary blades 71, 72 are implemented in a conventional manner on the body 10 advantageously before the assembly of the other él ments as described above. The assembly of the cage according to FIG. 2 is carried out in the same manner as described above, except that the nut 62 is introduced beforehand between the two blades and that, after the positioning of the first blade 31 against the first portion wall 36, the nut is screwed onto the thread 61 to block the first blade on the first wall portion 36, and consequently all the elements. The assembly of the cage according to FIG. 3 is carried out in the same manner as described above, except that, to press the first blade 41 against the first wall portion 36, the blade is screwed onto the threading 61.

Claims (11)

REVENDICATIONS1. An intersomatic cage adapted to be interposed between two vertebrae in replacement of an intervertebral disk, said intersomatic cage comprising a substantially cylindrical body (10) of generally cylindrical shape (11) comprising a substantially central through-hole (20) made substantially along axis (21). parallel to the generatrix of the cylindrical shape, locking means of said body (10) with at least one of the two vertebrae, characterized in that the locking means are constituted by at least: • first and second blades (31, 32) whose overall width is at most equal to the height of said through-hole (20) and the overall length is greater than the height of this through-hole, • means (34) for coupling in rotating the first and second blades (31, 32) so that the latter are respectively in abutment on two first and second opposite portions (36, 37) of the inner wall (38) of lad passing hole (20) and that they are able to take any position between two first and second positions, the first position being one in which the two blades are entirely contained in said through-hole and the second position being that in which at least a portion of each blade emerges from said through-hole. 2. Cage according to claim 1, characterized in that the means (34) for coupling in rotation the first and second blades (31, 32) consist of: • a shaft (40) substantially perpendicular to the axis (21). ) of the through-hole (20), said shaft having two first and second ends (48, 49) rotatably mounted respectively in two first and second bearings (41, 42) formed in said body (10), respectively leading to the first and second opposite wall portions (36,37) of the inner wall (38) of the through-hole (20), and means for respectively mounting the first and second blades (31,32) on said shaft (40) so that they are locked in rotation and in translation relative to this shaft when they bear respectively on the first and second opposite wall portions (36, 37) of the inner wall (38) of the through-hole. 3. Cage according to claim 2, characterized in that said means for mounting respectively the first and second blades (31, 32) on said shaft (40) consist of: • two first and second holes (43, 44) made respectively in the first and second blades (31, 32), said shaft (40) having two first and second sections (45, 46) engageable by plugging respectively with these first and second orifices, • a shoulder (50) of an overall cross section greater than the overall section of the second port (44) and at most equal to the overall section of the first port (43), said shoulder being provided on said shaft (40) so that, when the second end (49) of the shaft is rotatably mounted in the second bearing (42) and said second blade (32) is mounted on the second section (46) of the shaft (40) and bears against the second portion (37) of the inner wall of the through-hole e (20), said shoulder (50) is in contact with said second blade (32), the latter being located between said shoulder (50) and the second end (49) of the shaft (40), and • means (60) for locking the first blade (31) so that when said first blade (31) is mounted on the first section (45) of the shaft and both ends (48, 49) of the shaft ( 40) are respectively mounted in rotation in the first and second bearings (41, 42), said first blade bears against the first portion (36) of the inner wall (38) of the through-hole (20). 4. Cage according to claim 3, characterized in that the means (60) for locking said first blade (31) consist of at least one of the following means: • a hole (63) made transversely to the shaft ( 40) and a pin adapted to cooperate with said hole (63), to take the first blade (31) sandwiched between it and the first portion (36) of the inner wall (38) of the through-hole (FIG 1) ; A length of the first section (45) of the shaft (40) greater than the thickness of the first blade (31), a thread (61) formed on the first section (45) of the shaft (40) and a nut (62) adapted to be screwed on this first section (45) to take the first blade (31) sandwiched between it (62) and the first portion (36) of the inner wall (38) of the through-hole ( Fig. 2); A length of the first section (45) of the shaft (40) greater than the thickness of the first blade (31), a thread (61) formed on the first section (45) of the shaft (40) and tapping the first orifice (43) formed in the first blade (31), said tapping being complementary to said threading so as to allow the first blade (31) to come into contact with the first portion (36) of the wall inside (38) of the transverse piercing when screwed onto the first section (45) (Fig. 3). 5. Cage according to one of claims 1 to 4, characterized in that it comprises at least one auxiliary blade (71, 72), said auxiliary blade (71, 72) being rotatably mounted relative to the body (10). ) in said through-hole (20) in a plane substantially perpendicular to the planes passing through the first and second blades (31, 32), so that it is able to assume any position between two positions, one being that in which it is entirely contained in the through-hole and the other being the one in which it emerges from the through-hole, and means for controlling the rotation of said auxiliary blade (71, 72). 6. Cage according to claim 5, characterized in that the means for controlling the rotation of said auxiliary blade (71, 72) consist of one of the first and second blades (31, 32) which is arranged so that when rotated by means of said shaft (40), it rotates said auxiliary larva (71, 72). 12 7. Cage according to one of the preceding claims, characterized in that at least one of the two orifices (43, 44) is of polygonal shape. 8. Cage according to one of the preceding claims, characterized in that it comprises means (80) for controlling the rotation of said shaft (40) to pass the first and second blades (31, 32) of the one of their first and second positions to another. 9. Cage according to claim 8, characterized in that the means (80) for controlling the rotation of said shaft (40) consist of an open hollow recess (81) made in one end (48, 49). ) of said shaft (40). 10. Cage according to one of the preceding claims, characterized in that it further comprises a threaded cavity formed in said shaft, said threaded cavity being adapted to cooperate with an ancillary end bearing a thread complementary to that of said cavity. 11. Cage according to claim 10 when it depends on claim 9, characterized in that said threaded cavity is at least one of the following forms: (i) made in the bottom of said recessed housing, (ii) ) constituted by the hollow housing itself.