WO2012056119A1

WO2012056119A1 - Cervical cage and plate system

Info

Publication number: WO2012056119A1
Application number: PCT/FR2011/000540
Authority: WO
Inventors: Nicolas Guena; Alain Lerch; Jacques Flageollet; Gilles Dubois
Original assignee: Kasios
Priority date: 2010-10-29
Filing date: 2011-10-04
Publication date: 2012-05-03
Also published as: FR2966720A1; BR112013010019A2; FR2966720B1; EP2632391A1

Abstract

System for support and intersomatic fusion of the vertebrae, consisting of an intersomatic cage (1) with a continuous hole extending through it in a vertical direction and opening out at the upper and lower faces (7, 8) of the cage, and of a plate (27), which is fixed to the cage and protrudes from both the lower and upper sides of the cage, the plate being designed to be anchored to an upper vertebra and to a lower vertebra, characterized in that the plate is fixed to the cage while at the same time being able to slide relative to the cage between at least two different positions of anchoring of the plate to lower and upper vertebrae.

Description

Cervical cage and plate system.

The present invention relates to a cervical cage and plate system that can be positioned on two cervical vertebrae, in particular successive, and intended to promote the fusion of these vertebrae together (so-called interbody fusion). Several such systems may in particular be superimposed on several levels of cervical vertebrae, including adjacent.

Known systems of this kind comprise an intersomatic cage and a plate disposed substantially perpendicularly to the general plane of the cage and provided at these two free ends which project from the upper side and the lower side of the cage of respective fastening means to the one of the vertebrae, including fixing means in the form of a hole and a screw.

The intersomatic cage is pierced centrally by opening on its upper face and on its lower face by two upper and lower openings. It is intended to receive cancellous bone and to be interposed between two vertebrae to allow the establishment of a bone graft or a material promoting fusion between the two vertebrae, the bone graft passing through the cage and merging with the two vertebrae on either side of the cage.

These systems of the prior art have the disadvantage that it is difficult to fix two systems of this kind, on either side of the same vertebra respectively between the following vertebra (upwards in the direction of the column). vertebrae from bottom to top) and the previous vertebra (downwards in the direction of the spine from low to top) of said vertebra. Indeed, in such a case, there appears an interference between the upper end of the plate of the lower system and the lower free end of the plate of the upper system and it is difficult, if not impossible, to fix these two free ends, namely respectively the lower end of the plate associated with the upper cage and the upper end of the plate associated with the lower cage, except to accept that these two ends share the same anchoring points on the vertebra, which poses a problem, in particular tends to decrease the robustness of this vertebra.

It has already been thought in the prior art to solve this problem by producing a plate that can be pivoted with respect to the anteroposterior axis of the cage so as to allow two successive plates to be arranged in the height direction along the spine. in a staggered arrangement. These staggered sloping plate systems in the lengthwise direction of the spine, however, also have disadvantages. On the one hand, the mutual maintenance of the vertebrae is not as good as when the plates are arranged vertically. On the other hand, the system for fixing and pivoting the plate relative to the cage to ensure rotation of the plate relative to the anteroposterior axis of the cage is of complex structure. In addition, although offering more possibility than the fixed plates mounted perpendicularly to the cage, these staggered assemblies do not however allow to choose between many mounting positions of each plate vertebrae, independently of each other , the inclined position of the bottom cage plate largely determining the inclined position of the plate of the next upper cage.

In documents FR 2747034, WO 2005/077039, US 2008/0312742, US 2010/0057206 and EP 1103236, the plate can be anchored to two upper and lower neighboring vertebrae only in a single relative position of the cage and the plate. Document US 2008/0051890 describes a cage-plate system in which the plate can be fixed to the cage in several relative positions. However, the plate can not slide relative to the cage between the positions while remaining attached to the cage.

The present invention aims at overcoming the disadvantages of the devices of the prior art by proposing a system of the kind mentioned above with associated cage and plate which, although of very simple structure, also makes it possible to have a large number of possible positions of two successive plates without these being interfering with each other with respect to their anchoring to the same vertebra, this large number of anchoring positions of each plate vertebrae to choose a positioning of these anchors such as the maintenance of vertebrae relative to each other is made as stable as possible and in particular is much more stable than in the case of systems of the prior art. In addition, the present invention is a cage-plate system with several relative positions of the plate and the cage which is very easy to use, in particular to move from one relative position to another.

According to the invention, a system for the compression and interbody fusion of the vertebrae is as defined in Claim 1. Improvements are defined in the subclaims.

According to a preferred embodiment of the invention, the plate is slidably mounted relative to the cage in the mediolateral direction.

Preferably, the plate is an oblong piece, in particular of rectangular shape and the longitudinal axis of the plate is perpendicular to the plane of the upper and / or lower faces of the cage.

In particular, according to a preferred embodiment, the plate is an oblong piece, in particular of rectangular shape and the longitudinal axis of the plate is inclined with respect to the plane of the upper and / or lower faces of the cage while being in the plane defined by the vertical axis and the medio-lateral axis.

According to a preferred embodiment of the invention, at each free end of the plate there are ^provided means for anchoring the plate to a respective vertebra of the two vertebrae between which is intended to be arranged the cage, including a hole intended to cooperate with an associated screw.

According to a preferred embodiment of the invention, the plate is slidably mounted relative to the cage so that the two elements, the cage and the plate, are not detachable from one another.

According to a preferred embodiment of the invention, the cage comprises at least one hollow guide groove in an upper and / or lower face of the cage, preferably two guide grooves respectively formed in the upper face of the cage and the lower face of the cage, and in which a guide pin respectively engages to allow the sliding of the plate relative to the cage.

Thus, in particular, according to a particularly preferred embodiment, the cage comprises two lower and upper grooves which each extend between two end walls and the plate comprises a C-shaped hook each of which. free end is trapped in a respective groove, the sliding of the plate relative to the cage thus being between two extreme left and right positions without the plate can be detached from the cage.

According to a preferred embodiment, the cage comprises at least one groove in which is received a rib from the plate, the rib being slidably guided by the groove, in particular the cage has two upper and lower grooves and the plate has two ribs having a tenon-shaped end which are each received in one of the grooves.

Preferably, in section the two ribs, the two tenons and the part of the plate between the two ribs have the shape of a C-shaped clamp which clings to the cage by the two pins which penetrate into a respective groove and slide there.

Preferably, the system comprises an instrument shaft for placing it. In particular, according to an improvement, the instrument stem comprises a cylindrical body at an upper or distal end which extend a complementary shaped stud of a through hole formed in the plate and at least one lug, preferably two pins arranged ( s) on either side of the stud, at a distance from it, protruding from the body of the rod of a greater height than the stud.

The height of the lugs is greater than the height of the stud, so that the stud does not protrude from the plate and does not penetrate into the hole of the cage, while the lugs themselves penetrate between the two head plates, for thus prevent a rotation but allow however a mediolateral sliding.

According to a preferred embodiment of the invention, a flat head is formed at the upper end of the rod, the stud protruding from a central portion of the lateral surface of the head while the at least one pin, of preferably the two lugs, is projecting from a lateral portion of the lateral surface of the head, in particular the left and right lateral edges of the lateral surface of the head.

According to a preferred embodiment of the invention, two left and right rungs are formed on the upper surface of the head, so as to form a central open channel having a width corresponding substantially to the width of the plate, to thereby allow to the plate to be blocked in this channel when the stud has penetrated into the corresponding hole formed in the plate. Preferably, at least the end of the stud comprises a thread and the associated through hole formed in the stud comprises a corresponding thread, so that by screwing the end of the stud into the hole of the plate, it ensures a bonding of the plate to the stem.

Preferably, the stud consists of a sub-rod which is received in a through shaft formed in the cylindrical body of the rod, the relative displacement of the sub-rod relative to the rod being done by screwing, in particular the inner wall. well being threaded and the sub-rod having an associated thread.

The present invention also relates to an instrument rod for installing a cage-plate system according to the invention.

By way of example, a preferred embodiment of the invention will now be described relating to the drawings in which:

Figure 1 is a perspective view of an intersomatic cage of a system according to the invention;

Figure 2 is a top view of the cage of Figure 1;

Figure 3 is a sectional view along the line III-III of Figure 2;

Figure 4 is a perspective view of a plate of a cage system and plate according to the invention for cooperating with a cage as shown in Figures 1 to 3; Figure 5 is a top view of the plate of Figure 4;

Figure 6 is a sectional view along the line VI-VI of Figure 5;

Figure 7 is a perspective view of a cage and plate system, the plate being slidably mounted relative to the cage in a non-detachable manner;

Figure 8 is a perspective view of the system of Figure 7, when it has been turned 180 ° to see its lower part which is here facing upwards;

Figure 9 is a sectional perspective view of the cage and plate system of Figures 7 and 8, the sectional plane being the vertical anteroposterior plane;

Figure 10 shows, seen from the posterior side, three cages and three plates arranged on the spine, four vertebrae are represented, a stack on three levels;

Figure 11 shows in perspective the cage-plate assembly in which the plate has been shifted to the left by sliding relative to its central position shown in Figures 7 to 9;

Figure 12 shows in perspective the cage-plate assembly in which the plate has been shifted to the right by sliding relative to its central position shown in Figures 7 to 9; Figure 13 shows the cage-plate assembly in perspective with the plate in its central position in which the holes 60 and 24 are in concordance;

Figure 14 is a perspective view of an instrument rod for positioning the cage-plate assembly between two vertebrae;

Figure 15 is a front view of the instrument shaft of Figure 14;

Figure 16 is a side view of the instrument shaft of Figures 14 and 15;

Figure 17 is an enlarged view of an upper portion of the _. Figure 16;

Figure 18 is a sectional view ^following the line AA of Figure 17;

Figure 19 is a side view substantially identical to Figure 15, but on a larger scale of an upper portion of the rod instrument;

FIG. 20 is a view of a cage-plate assembly according to the invention and of an instrument rod in the position in which the cage-plate assembly can be inserted between two vertebrae using the instrument stem, the view being in perspective substantially from above; and

Figure 21 is a perspective view of the assembly and the rod of Figure 20 according to another axis of view. In FIG. 1, the cage 1 is generally parallelepipedal in shape having an anterior lateral external face 2, a posterior lateral external face 3, two lateral external faces 4 and 5 right and left, an upper outer face 7 and a lower outer face. 8. The cage is pierced centrally with a hole 9 of substantially circular section which opens to the upper and lower faces by two upper and lower openings. The cage thus defines around the hole 9 an annular shape consisting of an anterior section 10, a rear section 11 and two sections 12 and 13 right and left.

Bone material or bone substitute can thus pass through the cage through the hole 9 to promote fusion between the two vertebrae between which the cage has been inserted.

From the posterior face 3, two plates 14 and 15 forming promontories, respectively upper and lower, project from the posterior face 3. These two plates are spaced from each other in the vertical direction (the direction of the spine). They are furthermore also each slightly recessed with respect to the upper and lower faces, respectively.

In the upper face of the upper plate 14, a longitudinal groove 16 is formed in the mediolateral direction and in the lower face of the lower plate 15, a longitudinal groove 17 is formed in the mediolateral direction. Each of these grooves is delimited by a longitudinal wall 18, by the rear face 3 of the cage and two walls 19 and 20 left and right end.

The system also comprises a plate 27 shown in isolation in FIGS. 4 to 6. This plate 27 has an elongated, substantially rectangular shape having a width dimension (in the direction perpendicular to the plane of FIG. 6) and a length dimension (in the vertical direction in Figure 6). The plate has at its two free ends holes 28 for allowing the passage of screws (not shown in the figures), for screwing. from each end of the plate to an associated vertebra. The hole at the upper end in FIGS. 5 or 6 is intended to assist in anchoring the plate to a vertebra lying above the cage 1, while the hole 28 in the lower end in FIG. 6 is intended to allow anchoring of the plate to the lower vertebra which is below the cage 1.

From one of the faces of the plate (the anterior face), project two ribs 30 and 31 which extend over the entire width of the plate. These two ribs 30 and 31 are spaced from each other and have at their respective free end two pins 40, 41 which project laterally ribs. The two pins 40 and 41 are directed towards each other, so that the distance from which they are separated is less than the greatest distance (measured in the direction perpendicular to the ribs) between the ribs.

In longitudinal section, as shown in FIG. 6, the two ribs and the portion of the plate that extends between them have the shape of a C (reversed in Figure 6).

The distance between the two plates 14 and 15 promontories (from the lower face of the lower plate to the upper face of the upper plate) is substantially equal (while being however slightly lower) to the distance between the two inner faces of the two ribs 30 and 31. The two ribs 30 and 31 thus surround the two plates and the two end tenons 40 and 41 of the ribs are received in the respective grooves 16 and 17 and thus prevent the detachment of the plate from the cage. At the same time, however, the two pins can slide in the grooves to thereby allow sliding of the plate relative to the cage in the mediolateral direction. This sliding is limited to left and right by the two end walls 19 and 20.

At the level of the junction between the left and right walls and the longitudinal wall 18 of each groove, recesses 50 are formed which enlarge the width dimension of each groove at the ends and which make it possible, by a tilting action in connection with the elasticity of the material (generally thermoplastic or biocompatible metal) forming the ribs, to secure the plate to the cage or remove it.

Two semi-circular cutouts are formed in the upper surface of the lower plate and in the lower surface of the top plate to form a kind of virtual hole in which is received a circular sleeve 60 for receiving a tool for laying the cage. This is a classic feature of interbody cages and is not described in more detail here. The sleeve 60 comprises in particular a tapping or milling.

In addition, the plate 17 has at its center, between the two ribs 30 and 31, a hole 24 intended to correspond with the virtual hole, to allow the passage of a set tool assembly.

In FIG. 9, a sectional view is taken at the level of the plane defined by the anteroposterior axis and the vertical axis and in perspective the assembly consisting of cage 1 and a plate 27 as shown in FIGS. and 8.

As can be seen in this FIG. 9, the upper face 62 of the upper rib 30, when the pin 40 is received in the groove 16, is substantially flush with the upper outer face 7 of the cage, while the face 61 bottom of the lower rib 31, when the pin 41 is received in the groove 17, is substantially flush with the outer face 8 of the lower cage. To facilitate the establishment of the whole cage and plate between two vertebrae, it is important that these two faces 62 and 61 do not exceed, respectively upwardly and downwardly, respectively upper 7 and lower 8 faces of the cage.

When, for example as shown in Figure 10, it is desired to have between four vertebrae VI, V2, V3 and V4 of the spine, three cages, namely a lower linf cage, an intermediate lint cage and an upper Isup cage, secures the plate 27 of the cage lsup both to the upper vertebra VI and to the upper intermediate vertebra V2, the plate 27 of the intermediate cage both at the upper intermediate V2 vertebra and the lower intermediate V3 vertebra and the plate 27 of the lower cage both at the lower intermediate V3 vertebra and the lower V4 vertebra.

As shown in the figure, two plates must be attached to each intermediate vertebra V2 and V3. If we installed the set with the relative positions of the cage _. and the plate as shown in Figures 7 and 8, that is to say with the plate positioned substantially in the middle of the grooves 16 and 17, there would be interference between the two plates to be fixed to the same vertebra. According to the invention, by virtue of the fact that the plate slides relative to the cage, the two plates attached to the same vertebra can be shifted by sliding them each in an opposite direction, respectively left (as also shown in FIG. 11). and right (as also shown in Figure 12), with respect to the central position shown in Figures 7 to 9 and 13 (wherein the two holes 60 and 14 are in concordance), so that they are thus fixed on the vertebra being side by side without interfering with each other.

In addition, thanks to this sliding, which has a large deflection, there are many possible relative positions between the two plates, which allows to choose the position that gives the greatest stability, in particular as shown in Figure 10 in which two plates attached to the same vertebrae are respectively shifted to the left and to the right by the same distance relative to the central position.

Figures 14 to 19, there is shown a rod-shaped laying instrument for coupling to the cage-plate assembly to allow 1 insertion between two vertebrae in particular.

This instrument consists of a main body 100 in the form of a substantially circular cylinder at the upper end of which projects a head 101 of larger dimension in width. The upper surface of the head 101 has a central flat face 102 from which a circular cylindrical stud 103 of smaller dimension than that of the flat surface 102 projects. In addition, two shoulders 104 and 105, right and left, are formed on this surface. 102, the two shoulders 104 and 105 thus forming two steps or side steps on the right and left sides respectively.

Upper faces of the two lateral steps 104 and 105 project two pins 106 and 107.

To install the cage-plate, represented for example in FIGS. 9 and 11 to 13, the instrument rod 100 is taken and the stud 103 is inserted into the hole 24 formed in the plate. The relative dimensions of the hole 24 and the stud 103 are such that the stud 103 can penetrate into the hole 24, preferably having substantially the same dimensions and in complementary form. The extension in length, that is to say in the longitudinal direction of the rod of the stud 103 is however such that it does not penetrate into the hole 60 of the cage so as not to prevent the plate from sliding in the direction of mediolateral sliding. At the same time that the stud 103 enters the hole 24, the two lugs 106 and 107 penetrate them into the groove formed between the two plates 14 and 15 in the form of a promontory of the cage to thereby block any possibility of rotation of the rod. instrument and plate relative to the cage.

Once the central stud 103 inserted into the hole 60 and the lugs disposed within the groove formed between the two plates 14 and 15, it pushes with the rod the plate and cage together between the two vertebrae. The cooperation between the rod and the plate is such that the rod and the plate are secured in displacement, so that once the cage inserted between two vertebrae, can then by displacement of the rod slide the plate relative to the cage to place it exactly in the position in which one wishes to fix it to the vertebrae. Thus, the width dimension of the central face 102, between the two shoulders 104 and 105, corresponds substantially to the width of the plate or in any case is greater than the width of the plate so that it can be received between the plates. shoulders.

20 and 21, when the instrument stem is placed in cooperation with the cage-plate assembly, that the lugs 106 and 107 penetrate into the groove formed between the two plates 14 and 15 and thus ensure a locking in rotation by relative to the axis of the stem and guide in translation sliding in the mediolateral direction moving the entire plate and rod instrument.

The hole 24 in the plate 27 has a thread.

The stud 103 consists of a sub-rod which can move inside a well 109 formed inside the rod 100.

A distal end portion of the stud 103 is threaded so as to be screwed into the tapping of the hole 24 and thus secure the rod to the plate.

The well 109 is threaded and at least one section of the sub-rod is threaded to allow movement by screwing the sub-rod relative to the rod. This threaded section is different from the threaded distal end portion.

The shapes and dimensions of the stud, plate and cage and their corresponding thread and thread are made so that the free end of the stud 103 does not exceed the face of the plate on the side of the cage and in particular does not penetrate the hole 60 to not prevent the mediolateral sliding of the plate relative to the cage. In particular, the end of the stud 103 is flush with the face of the plate. According to an improvement, it is possible in the hole 24 a flange at the side of the plate on the side of the cage which blocks the rod and prevents it from screwing further. Of course, other locking means can be envisaged and it is also possible, without departing from the scope of the present invention, not to provide such locking means. For example, one can predict that in his distal portion the stud or under rod is threaded only over a distance corresponding to the depth of the hole in the plate, a neighboring section of this distal portion of the sub-rod not being threaded.

In FIG. 10, three cage-plate systems identical to that of FIGS. 7 to 9 are shown.

The cage-plate system of the top of the figure (between Vi and V ₂ ) is anchored to Vi and V ₂ in a first relative position of the cage and the. plate. The cage-plate system of the middle of the figure (between V ₂ and V ₃ ) is anchored to V ₂ and V ₃ in a second relative position of the cage and the plate different from the first position.

The cage-plate system of the bottom of the figure (between V ₃ and V ₄ ) is anchored to V ₃ and V ₄ in a third relative position of the cage and the plate which is here identical to the first position, but could, if desired, be different from the first, for example be more shifted to the left. As can be seen, the plate can be slid relative to the cage between a plurality of different relative positions of the cage and plate in which the cage-plate system can be anchored to two upper and lower neighboring vertebrae by intermediate anchoring means (holes 28 and corresponding screws) carried by the plate.

Claims

REVENDICA IONS

A system for intervertebral compression and fusion of the vertebrae comprising an intersomatic cage (1) pierced by a through hole extending in a vertical direction and opening to the upper and lower faces (7, 8) of the cage and a plate (27) attached to the shaft protruding on both sides ^■ top and bottom of the cage, the plate being intended to be anchored to an upper vertebra and a lower vertebra, characterized in that the plate (27) is attached to the cage while being slidable relative to the cage (1) between at least two different anchor positions of the plate at the lower and upper vertebrae.

System according to Claim 1, characterized in that the plate (27) is slidably mounted relative to the cage (1) in the mediolateral direction.

System according to Claim 1 or 2, characterized in that the plate (27) is an oblong piece, in particular of rectangular shape, and the longitudinal axis of the plate is perpendicular to the plane of the upper and / or lower faces (7, 8). of the

System according to Claim 1 or 2, characterized in that the plate (27) is an oblong piece, in particular of rectangular shape and the longitudinal axis of the plate is inclined relative to the plane of the upper and / or lower faces of the cage while being in the plane defined by the vertical axis and the medio-lateral axis.

System according to one of claims 1 to 4, characterized in that at each free end of the plate is provided means (28) for anchoring the plate to a respective vertebra of the two vertebrae between which ^" is intended to the cage is disposed, in particular a trud for cooperating with an associated screw.

System according to one of the preceding claims, characterized in that the cage (1) comprises at least one groove (16, 17) in which is received a rib (30, 31) issuing from the plate, the rib both guided in sliding by the groove.

System according to claim 6, characterized in that the cage has two upper and lower grooves (16, 17) and the plate has two ribs (30, 31) having a tenon-shaped end (40, 41) which are each received in one of the grooves.

System according to claim 7, characterized in that in section the two ribs (30, 31), the two pins (40, 41) and the portion of the plate (27) between the two ribs are in the form of a clamp C-shaped which clings to the cage by the two pins that penetrate into a groove (16, 17) and slide there. System according to one of claims 6, characterized in that the rib or ribs (30, do not project from external surfaces

upper and / or lower of the cage.

System according to one of the preceding claims, characterized in that the plate (27) has a hole (24) therethrough and there is provided an instrument shaft (100) for positioning the cage-plate system, the instrument shaft ^" comprising a body cylindrical at an upper or distal end which extend a stud (103) of complementary shape of the through hole formed in the plate and at least one lug, preferably -two lugs (106, 107) arranged (s) on both sides other of the stud, at a distance from it, projecting from the body of the rod of a greater height than the stud.

11. System according to claim 10, characterized in that the hole (24) through is threaded and the distal end of the pad (103) is threaded correspondingly.

System according to claim 11, characterized in that the stud (103) is slidably mounted relative to the rod (100), in particular by being in the form of a sub-rod received in a well (109) of the rod.