FR3082115A1 - VERTEBRAL OSTEOSYNTHESIS MATERIAL - Google Patents

Abstract

This material includes: an intervertebral implant (2) forming two superimposed parts (10, 11) bearing against the vertebrae, separated from each other and movable relative to one another between a position of approximation and a spacing position; and - a distraction member (3), capable of being forcibly engaged between these superimposed parts (10, 11). According to the invention, at least one of the two superimposed parts (10, 11) forms, on a proximal side of the implant (2), an anchoring block (20, 22) extending over at least half the height of the implant (2); and - said anchoring block (20, 22) is pierced with a hole (30) for the engagement through it of a bone anchoring screw (4) capable of being screwed into one of the vertebrae .

Description

The present invention relates to vertebral osteosynthesis material including an intervertebral implant, in particular for the treatment of cervical vertebrae.

It is well known to treat the degeneration of an intervertebral disc by inserting an intervertebral implant between the two vertebrae concerned, in order to distract these two vertebrae to reposition them adequately with respect to each other, then leaving s '' operate a bone cell growth around this implant, as well as possibly through this implant, so as to achieve a bone junction between these two vertebrae, this bone junction achieving immobilization of the two vertebrae one with respect to the other.

A known intervertebral implant, in particular suitable for the treatment of cervical vertebrae, has a structure with two superimposed parts, movable relative to one another between a position of approach allowing the insertion of the implant into the intervertebral space, and a spreading position allowing the distraction of the vertebrae. In particular, the publication of patent application No. FR 2 866 228 describes an implant having the two movable parts in question and a distraction screw, capable of being forcibly engaged between these superimposed parts. The two movable parts are individualized with respect to each other by a slot extending over a major part of the implant, at mid-height thereof, from the proximal side of this implant to near on the distal side thereof and from one lateral side to the other thereof; on the distal side of the implant, said movable parts are connected to each other by a wall of reduced thickness; the movable parts are, in a state of non-deformation of the implant, in said approach position, and are capable of being spaced from one another by the deformability of the material, in particular metallic, constituting the implant.

The distraction screw has an enlarged head and is engaged in a distal threaded bore; during the screwing of the screw, the enlarged head bears against inclined walls which form the mobile parts and thus realizes, as it progresses in the distal direction, the passage of the two mobile parts from said position of approach to said spreading position.

Such an intervertebral implant must be immobilized as much as possible relative to the two paired vertebrae while bone cells are growing, so that the patient's movements do not risk modifying the position of the implant, or even expelling it. implant outside the intervertebral space treated. Such fixation is particularly necessary when the vertebrae treated are cervical vertebrae.

To achieve this fixation, it is known to provide notches or ridges on the faces of the movable parts coming to bear against the vertebrae, as described in the above-mentioned prior document; these means are generally not sufficient to allow reliable immobilization of the implant in the intervertebral space; this results in the need to immobilize the patient over an extended period, which is a strong constraint for the patient.

To date, there is no vertebral distraction intervertebral implant making it possible to improve the attachment of the implant to the vertebrae until the growth of the bone cells around the implant occurs, and the present invention aims to objective to provide an answer to this gap.

The vertebral osteosynthesis material concerned comprises, in a manner known per se,

- an intervertebral implant forming two superimposed support parts against the vertebrae, separated from each other and movable relative to each other between a position of approximation allowing the insertion of the implant in a space intervertebral and a position of separation allowing the distraction of the vertebrae; and

- A distraction member, capable of being forcibly engaged between these superimposed parts, bearing against these superimposed parts so as to pass the latter from the approach position to the spacing position.

According to the invention,

- At least one of the two superimposed parts forms, on a proximal side of the implant, an anchoring block extending over at least half the height of the implant; and

- Said anchoring block is pierced with a hole (30) for engagement through it with a bone anchoring screw capable of being screwed into one of the vertebrae.

Thus, the implant according to the invention does not have a transverse slot extending between said parts superimposed on the proximal side of the implant but comprises at least one anchoring block extending over at least half the height of the implant; the height of the anchoring block is such that a hole (30) for engaging a bone anchoring screw can be arranged through this block and an anchoring of the implant by screws can thus be realized. Thanks to this screw anchoring, the immobilization of the implant relative to the treated vertebrae is perfectly ensured while the bone cells are growing.

By considering the implants according to the prior art, in particular that described by the aforementioned patent application, the inventors could conceive that the impossibility of carrying out an anchoring by screw resulted from the presence, on the proximal side of the implant, of the slot arranged at mid-height of the implant making it possible to individualize the two superimposed parts; they could then conceive of overcoming the presence of this slot on this proximal side, at least in part, by providing at least one anchoring block capable of receiving a bone anchoring screw.

It will be understood that the term proximal is to be considered very conventionally, as meaning a location closer to the practitioner than a distal location, and that the expression height of the implant defines the dimension of the implant in a perpendicular direction. the faces by which the implant comes to bear against the respective vertebrae.

Preferably,

each anchoring block has a height greater than half the height of the implant, in particular equal to this height, and

- The superimposed part not including this block forms a notch allowing it to accommodate this block in the position of approximation of the superimposed parts.

The block thus has a significant height, allowing the arrangement in itself of a large diameter conduit, and consequently allowing the use of bone anchor screws themselves having a large diameter, which is advantageous for the solidity of the anchor obtained.

Preferably,

each of the two superimposed parts forms an anchoring block as mentioned above, and

- Each of the two anchor blocks is pierced with a hole (30) for engaging a bone anchor screw.

The material thus includes two bone anchoring screws, allowing a resistant and stable connection of the implant to the vertebrae.

Preferably, the two holes that comprise the two anchor blocks extend in directions going away from one another relative to a median plane of the implant substantially parallel to the faces through which the implant abuts against the vertebrae, so that one of the bone anchor screws is intended to be anchored in one of the treated vertebrae and that the other of the bone anchor screws is intended to be anchored in the other vertebrae treated.

An implant is then anchored to the two vertebrae.

According to a preferred embodiment of the implant comprising two anchor blocks, one of the anchor blocks is arranged on a lateral side of the implant while the other anchor is arranged on the other side lateral of the implant, said distraction member being located in the middle position of the implant, between the two anchoring blocks.

The gap thus produced between the two bone anchoring screws ensures the stability of the implant anchoring.

According to another aspect of the invention,

- Each bone anchor screw has an anti-recoil tab fitted in its part intended to be inside the anchor block in the anchor position, having a proximal locking face; this tongue is movable by elasticity between a radially internal position in which it is integrated into the circumference of said part of the screw, and a radially external position in which it projects relative to this circumference of the part of the screw and in which said proximal locking face protrudes from said portion of the screw; and

the anchoring block forms a groove for receiving the tongue in said anchoring position, this groove being delimited at the proximal level by a locking rim capable of cooperating with said proximal locking face, to ensure anti-recoil blocking of the screw.

The tongue may in particular be formed by the material of the screw itself and be individualized by, on the one hand, on the radially internal side of this tongue, by an axial bore which the screw has, and, on the other hand, by a U-shaped cutout arranged through the wall of the screw.

The invention will be well understood, and other characteristics and advantages thereof will appear, with reference to the appended schematic drawing, representing, by way of nonlimiting examples, two possible embodiments of the material concerned.

FIG. 1 is a perspective view of this material according to a first embodiment, including an intervertebral implant, two bone anchoring screws and a distraction screw, these various screws being removed relative to the implant;

Figure 2 is a side view of the implant, from the proximal side thereof;

Figure 3 is a view of the implant in section along the line III-III of Figure 2;

Figure 4 is a perspective view of the material from another angle than Figure 1, and with the aforementioned screws placed in the intervertebral implant;

Figure 5 is a view of the top equipment;

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

Figure 7 is a sectional view along the line VII-VII of Figure 5;

Figure 8 is a view similar to Figure 6, in a position of separation of two movable superimposed parts that includes the implant;

Figure 9 is a view similar to Figure 2, in the same spacing position;

Figure 10 is a perspective view of one of the bone anchor screws, on an enlarged scale;

Figure 11 is a partial view of this screw, from the side;

Figure 12 is a partial view of the screw, in section along the line XII-XII of Figure 10; and Figure 13 is a view of the implant similar to Figure 2, according to a second embodiment.

FIGS. 1 to 7 represent a vertebral osteosynthesis material 1 including an intervertebral implant 2, a distraction screw 3 and two screws 4 for anchoring the bone of this implant 2.

The implant 2 has, as is well known, upper and lower main faces intended to come into abutment against the vertebral plates of the two treated vertebrae, and has, perpendicular to these main faces, a proximal side, a distal side and two lateral sides. These references in space are to be considered, very conventionally, in relation to the position than to the implant when it is placed on a patient and the patient is standing, and the term proximal designates very conventionally a location closer to the practitioner while the term distal designates a location further away from the practitioner.

The implant 2 forms two superimposed parts 10, 11 for bearing against the vertebrae, which are individualized and separated from each other by a transverse slot 12 extending from a lateral side of the implant 2 to the other, and by slit portions 12a, communicating with the slit 12, which extend to the proximal side of the implant 2. The superposed parts 10, 11 are connected to each other by a wall distal 13. The thickness of the superimposed parts 10, 11 and the thickness of the wall 13 are such that, considering the material of which the implant 2 is made, these superimposed parts 10, 11 and this wall 13 are slightly elastically deformable from so as to allow the passage of the superimposed parts 10, 11 from the non-deformation position shown in FIGS. 1 to 7, in particular in FIG. 6, in which the superimposed parts 10, 11 are brought together and allow insertion of implant 2 in an interve space rtebral, in the deformation position visible in Figures 8 and 9, allowing a distraction of the two vertebrae.

As shown in FIGS. 2 and 3, the parts 10, 11 jointly form, at their proximal median portions, a bore 14 for receiving the proximal portion of the distraction screw 3 and the wall 13 present, in its portion median, a boss 15 pierced with a threaded bore, for receiving the distal portion of the screw 3. The bore 14 internally forms, in line with this screw 3, conical wall portions 14a intended to cooperate with a conical zone 3a of the screw 3. As appears in FIGS. 8 and 9, when the screw 3 progresses by screwing into the distal threaded bore, the portion 3a bears against the wall portions 14a to carry out the passage of the superimposed parts 10, 11 from their normal position of approach to their deformed spacing position.

Each superimposed part 10, 11 also has a wide opening 16 on the distal side of the implant 2, allowing the placement in the space delimited by the implant 2 and by the screw 3, of one or more bone grafts , natural or synthetic, intended to be colonized by growing bone cells.

The superimposed parts 10, 11 also have on their outer faces, series of teeth arranged transversely promoting their connection with the bone of the vertebrae, by slight penetration of these teeth in this bone.

As shown in these Figures 1 to 7, the superimposed part 10 forms, on the proximal side of the implant 2 and on a lateral side of this implant relative to the bore 14, an anchoring block 20 forming a body with this part 10 and extending over the entire height of the implant 2, while the other superimposed part 11 forms a notch 21 allowing it to receive this block 20 in the position of approximation of the superimposed parts 10, 11 ; conversely, the superimposed part 11 forms, on the proximal side of the implant 2 and on the other lateral side of this implant relative to the bore 14, an anchoring block 22 forming a body with this part 11 and s' extending over the entire height of the implant, and the other superimposed part 10 forms a notch 23 allowing it to receive this block 22 in the position of approximation of the superimposed parts 10, 11. Of course, as visible on the Figure 2 each notch 21,23 is interrupted at a distance from the median axis of the bore 14 so that the surfaces by which the distraction screw 3 is intended to come to bear against the superimposed parts 10, 11 are sufficient.

Each anchoring block 20, 22 is pierced with a conduit 30 for receiving a bone anchoring screw 4; as shown in FIG. 2 and as distinguished in FIG. 7, each block 20, 22 forms a groove 31 coaxial with the conduit 30. This groove 31 constitutes a lateral space for receiving a tongue 35 anti-recoil, described below, which each bone anchoring screw 4 has, and the proximal axial end of this groove 31 forms a shoulder intended to cooperate with a proximal locking face 35a which this anti-recoil tongue 35 presents to perform the anti -back of a screw 4 relative to the implant 2.

With particular reference to FIGS. 7 and 10 to 12, it appears that each anchoring screw 4 has, below its proximal operating cavity 36, an axial threaded bore 37 and a cutout 38 in a U shape. This cutout 38 communicates the exterior of the screw 4 with this bore 37 and makes it possible to individualize said tongue 35, which is thus formed by the material constituting the screw 4, at the level of the head of this screw 4. This tongue 35 has at its base a thickness as it is movable by elasticity between a radially internal position in which it is integrated into the circumference of the head of the screw 4, and therefore does not prevent the progression of this head in the conduit 30, and a radially position external in which it projects relative to this circumference of the head of the screw 4. The tongue 35 has a proximal allowance for forming said proximal locking face 35a.

In practice, once the implant 2 is positioned in the intervertebral space to be treated, the screws 4 are put in place in the holes 30 and then in the bones of the vertebrae until the tongues 35 click into the grooves 31 and therefore activation of the anti-kickback system that constitutes each tongue 35 with the proximal shoulder formed by the corresponding groove 31. The implant 2 is thus perfectly anchored to the vertebrae and the distraction screw 3 can then be screwed to achieve the separation of the two superimposed parts 10, 11 without risk of mobility of the implant.

The threaded bore 37 is used to receive by screwing a tool allowing to exert a traction on the screw 4 by forcing the passage of the tongue 35 out of the corresponding groove 31, if it turns out to be necessary to extract the screw 4.

The anchoring of the implant 2 by means of the screws 4 allows the perfect immobilization of this implant 2 in the intervertebral space while the bone cells grow around and through the implant, which promotes the rapid recovery of the patient.

FIG. 12 shows another embodiment of the implant 2, in which the anchoring blocks 20, 22 do not extend over the entire height of the implant 2 but over only part of this height , at least half the height of the implant 2 and of the order of four-fifths of this height in the example shown. As soon as the height of a block 20, 22 is such that this block does not interfere with the superimposed part 10, 11 not including this block, it is not necessary to provide the notches 21, 23.

The invention has been described above with reference to embodiments provided by way of examples. It goes without saying that it is not limited to these embodiments but that it extends to all the other embodiments covered by the claims appended hereto. In particular, it would be conceivable to provide only one of the two anchor blocks 20, 22, and therefore a single bone anchor screw 4.

Claims (6)

1. Vertebral osteosynthesis equipment (1), comprising: - An intervertebral implant (2) forming two superimposed parts (10, 11) bearing against the vertebrae, separated from each other and movable relative to one another between a position of approach allowing the insertion of the implant (1) into an intervertebral space and a position of separation allowing the distraction of the vertebrae; and - a distraction member (3), capable of being forcibly engaged between these superimposed parts (10, 11), bearing against these superimposed parts so as to cause the latter to pass from the approaching position to the spacing position ; characterized in that: at least one of the two superimposed parts (10, 11) forms, on a proximal side of the implant (2), an anchoring block (20, 22) extending over at least half the height the implant (2); and - Said anchoring block (20, 22) is pierced with a hole (30) for the engagement through it of a bone anchoring screw (4) capable of being screwed into one of the vertebrae. 2. Equipment (1) according to claim 1, characterized in that: each anchoring block (20, 22) has a height greater than half the height of the implant (2), in particular equal to this height, and - The superimposed part (11, 10) not including this block (20, 22) forms a notch (21,23) allowing it to house this block in the position of approximation of the superimposed parts (10, 11). 3. Equipment (1) according to claim 1, characterized in that: each of the two superimposed parts (10, 11) forms an anchoring block (20, 22), and each of the two anchoring blocks (20, 22) is pierced with a hole (30) for engaging a screw (4) for bone anchoring. 4. Material (1) according to claim 3, characterized in that the two holes (30) that comprise the two anchor blocks extend in directions going away from one another relative to a median plane of the implant (2) substantially parallel to the faces by which the implant (2) bears against the vertebrae, so that one of the bone anchoring screws (4) is intended to be anchored in I one of the treated vertebrae and that the other of the bone anchoring screws (4) is intended to be anchored in the other of the treated vertebrae. 5. Equipment (1) according to claim 3 or claim 4, characterized in that one of the anchoring blocks (20,22) is arranged on a lateral side of the implant (2) while the other anchor block (22, 20) is arranged on the other lateral side of the implant (2), said distraction member (3) being located in the median position of the implant (2), between the two blocks d anchor (20, 22). 6. Equipment (1) according to one of claims 1 to 5, characterized in that: -each bone anchoring screw (4) has an anti-recoil tab (35) arranged in its part intended to be inside the anchoring block (20, 22) in the anchoring position, having a face proximal locking (35a); this tongue (35) is movable by elasticity between a radially internal position in which it is integrated into the circumference of said part of the screw (4), and a radially external position in which it projects relative to this circumference of the part of the screw (4) and wherein said proximal locking face (35a) projects relative to said part of the screw (4); and - The anchoring block (20, 22) forms a groove (31) for receiving the tongue (35) in said anchoring position, this groove (31) being delimited proximally by a locking rim capable of cooperating with said proximal locking face (35a), to ensure an anti-recoil blocking of the bone anchoring screw (4).