FR3006168A1 - BONE SEAL DISTRATENT - Google Patents

Abstract

The bone block according to the invention is essentially characterized by the fact that it comprises a U-shaped body 10 comprising two branches 11, 12 and a base 13; a cylindrical shaft 20 having a cross section whose thicknesses, defined along two axes X, Y, are of different values; a bearing 30 of axis 31 made in the facing faces 14, 15 of the two branches 11, 12; the shaft 20 being rotatably mounted in the bearing 30 and in contact with the two branches 11, 12; a tab 40; means for securing the tab 40 with the shaft 20; and means 50 for controlling the rotation of the shaft 20 in the bearing 30 relative to the body 10. Application to the bone blocks capable of being interposed between two portions of O1, O2 bone to join them to secure them together after they have been distracted.

Description

The present invention relates to an implant called "distracting bone wedge" intended to be implanted between two bones, or two bone portions, which must be connected for different reasons. Such a bone hold finds a particularly advantageous application, but not exclusively, to be interposed between the vertebral bodies of two consecutive lumbar vertebrae, instead of the deficient disc initially present between the two vertebrae. It allows the fusion of the vertebral bodies after dissectomy, while maintaining the bone distance. It finds another advantageous application, for example, as wedge able to be interposed between two spiny processes. Such bone wedges are already known, such as those described and illustrated in FR-A-2,715,293 and FR-A-2,866,229. Such a wedge according to the prior art comprises a shaped body. U having thereby two branches and a connecting piece connecting two first ends of these branches, a screw having a head bearing against the connecting piece and a screw rod defining a longitudinal axis 20 freely traversing the connecting piece and passing between the two branches, and a spacer movable in translation screwed onto the screw rod, this spacer being in sliding contact on both faces facing the branches. Such wedges play their role of distraction, but have a relatively complicated structure and can, especially in the early stages following their implantation, undergo parasitic displacements which undoubtedly harm the desired goal. The object of the present invention is to provide a bone wedge which allows both a distraction of the two bones between which it is intended to be implanted and a reliable attachment to these two bones, as well as possibly, in some cases, an increase of its support polygon, ie global surfaces on which the two bones can rest.

More specifically, the subject of the present invention is a bone block, characterized in that it comprises: a substantially U-shaped body comprising two branches and a base connecting two first ends of these branches; a cylindrical shaft having a cross section whose thicknesses, respectively defined along two axes forming between them a non-zero angle, are of different values, - a bearing defined according to a given axis of rotation, said bearing being made in the opposite faces of the two branches, said shaft cylindrical being rotatably mounted in said bearing between said two branches and in contact therewith, - a substantially flat tab, - means for mounting said tab in cooperation with said shaft so that the plane of said tab makes with said axis rotating a non-zero angle and said tab is rotated with that of said shaft, and - means for controlling the rotation of said arbor e in said bearing relative to said body. Other features and advantages of the present invention will appear on reading the following description given with reference to the accompanying drawings, in which: FIGS. 1 and 2 show two side views of a first embodiment of the bone wedge according to FIG. invention, in two possible configurations during its use, and Figures 3 to 5 show a second embodiment of the bone block according to the invention, applying the first embodiment according to Figures 1 and 2, Figure 3 being a view from above, FIG. 4 a side view and FIG. 5 an end half view according to the usual rules of the drawings, FIGS. 3 and 4 showing the wedge in its non-distracting position, and FIG. his distracting position. It is pointed out that the figures represent two 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.

It is also specified that when, in the present description, an expression alone defines, without specific specific reference to 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. Finally, it is specified that, in the present description, if the adverb "substantially" is associated with a qualifier of a given means, this qualifier must be understood in the strict sense or approached. FIGS. 1 and 2 show a first embodiment of the bone block according to the invention capable of being interposed between two bone portions 01, 02, for example two vertebral bodies or the like, with a view to uniting them to secure them between they have been distracted away from each other, for example to reduce a fracture or to remove two vertebral bodies in order to restore their original distance and reduce in a known manner back pain or the like. The shim comprises a substantially U-shaped body 10 having thereby two branches 11, 12 and a base 13 connecting two first ends 11-1, 12-1 of these two branches. Such a base 13 can be made in different ways, for example in one piece able to deform elastically and plastically without breaking, or in a patellar shape for large rotational amplitudes of the two branches, as mentioned. in dashed lines under the reference 13-ro.

According to another preferred embodiment, the two branches 11, 12 of the U-shape and the base 13 connecting two first ends 11-1, 12-1 of these branches are made in one piece of a biocompatible material, metal or other like Titanium, PEEK, etc.

The shim comprises a cylindrical shaft 20 having a cross section whose thicknesses, respectively defined along two axes X, Y forming between them a non-zero angle advantageously equal to ninety degrees, are of different values, and a defined bearing 30 along an axis of said rotation 31, this bearing being formed in the facing faces 14, 15 of the two branches 11, 12, the cylindrical shaft 20 being rotatably mounted in this bearing 30 between the two branches 11, 12 and in contact with them. The bearing 30 may be made in different ways, for example recessed on one of the two branches and flat on the other, or recessed on the two branches as shown in the figures, or even with two spaced stops one of the other and made in relief (for example two pins or the like) on the facing faces 14, 15 of the two branches 11, 12, the shaft 20 pivoting between these stops. The wedge comprises at least one substantially flat tab 40 and means for mounting this tab in cooperation with the shaft 20 so that the plane of the tab makes with the axis of rotation 31 a non-zero angle and that the tab is driven in rotation with that of the tree. According to one possible embodiment, these mounting means are securing means with the shaft 20, for example by crimping, welding, etc., and so that the plane of the leg makes an angle with the axis of rotation 31 not zero, advantageously equal to ninety degrees. According to an advantageous embodiment, the at least one lug 40 has a shape such that (FIG. 1), when the shaft 20 is in a first position P1 relative to the body 10 in which its largest thickness is defined along a straight line substantially parallel to the opposite faces 14, 15 of the two branches, it is at least largely, if not entirely, inscribed in the cross section of the body defined in the plane of the first U, to minimize its transverse size during its implementation. It should be noted that, by emerging very weakly, it can be used to achieve a beginning of distraction between the two bones 01, 02 without thereby affecting its transverse bulk. The tab further has a shape so that (Figure 2), when the shaft 20 is in a second position P2 relative to the body 10 in which its largest thickness is defined along a line substantially perpendicular to the facing faces 14 , Of the two branches, it overflows from the cross section of the body defined in the plane of the first U to implant in at least a portion of bone 01, 02, at least on one side of the body, even after distraction as mentioned in Figure 2 with a large amplitude of distraction to highlight the result that can be obtained with a wedge according to the invention. It is specified that the tab 40 can be made so that it is located only on one side of the shaft 20. It will then only have a part 40-1, 40-2 which will emerge from the body 10. However, in the majority of cases, it will have a shape like the one shown in FIGS. 1 and 2, so that it protrudes from the two opposite sides of the body to penetrate both bone portions 01 at a time. , 02 and thus ensure a good maintenance of these two portions of bone between them via the wedge according to the invention. In addition, this lug 40 may be in the form of a cutting blade to enable it to penetrate into a bone part, for example in an application as an intervertebral cage. But it may also not be sharp, to constitute an abutment intended to be pressed on a bone part or the like without penetrating it, as for example in an application to a wedge able to be inserted between two consecutive spinous processes. According to a preferred industrial embodiment, the cylindrical shaft 20 has a substantially elliptical cross section, as illustrated in the figures, the X and Y axes mentioned above being the axes of this elliptical section.

Even more preferably, the shim comprises locking-unlocking means 70 which cooperate with the lug 40 and the body 10 when the shaft 20 is at least in its second position P2, so when the lug protrudes from the body as explained herein. -before.

In addition, the portion of blade 40-1, 40-2 which overflows, Figure 2, may comprise means, not shown, adapted to fit into the bone portion. These means can be made in different ways, for example in the form of protruding ridges, for example in the form of a "comma" or the like, centered on the axis of rotation 31 with an increasing cross-section so that, as and when measurement of the rotation of the tab 40, whether the tab itself or not penetrate into the bones, these projecting ridges, they penetrate deeply and even embedded in it. It is emphasized that the tab 40 can be located in one of the following ways: on one side of the body 10, in a cavity made in the body.

The shim further comprises means schematically illustrated by the reference 50 for controlling the rotation of the cylindrical shaft 20 in the bearing 30 relative to the body 10. These means 50 for controlling the rotation of the shaft 20 in the bearing 30 by 10 to the body 10 may be constituted by at least one of the following means: (i) means for printing, to the shaft 20, a rotational force transmitted in a direction substantially parallel to its axis of rotation 31, for example in this case a screwdriver or the like adapted to cooperate with a hollow 51 at the end of the shaft 20, for example of polygonal section, as schematically illustrated in FIGS. 1 and 2, or (ii) means for printing, at 20, a rotational force transmitted in a direction substantially perpendicular to its axis of rotation 31, for example in this case a set of gears with a bevel gear or the like, not shown, one of the gears, of any type, being 30 in solidarity with e the shaft 20 and the other secured to a tool pivotable about an axis perpendicular to the axis 31 of the shaft 20. It is stated that this shaft 20 can be in one piece. But it can also be composed of two parts without material connection. In this way, the body may comprise a central cavity unencumbered by a shaft portion, and thus able to receive, in a known manner, for example a bone graft or the like of large volume. According to a possible and preferred embodiment, the shim comprises at least two substantially flat tabs 40 and means for mounting them in cooperation with the shaft 20 so that, as defined above, the plane of the tabs are made with the axis of rotation 31 a non-zero angle and that the tabs are rotated with that of the shaft. These two tabs may be located on two opposite outer faces 10 of the body 10, or on two opposite faces of the central cavity formed in this body defined above, or on an outer face of the body 10 and on one side of the cavity. It is even possible that the hold has more than two legs. When the shim has two tabs on two opposite outer faces of the body 10, it may constitute for example an interspinous wedge adapted to be implanted between two consecutive vertebrae so that the two tabs constitute stops coming from each side respectively of the two thorny processes of the two vertebrae. In this case, the wedge may further comprise a third leg, for example in a cavity such as that described above but which is traversed by the shaft 20, the latter then being preferably in one piece and cooperating with a bearing in each of the two branches 11, 12. This third lug secured to the shaft 20 as defined above makes it possible to secure the shim with at least one of the two spinous processes and to prevent the shim from slipping by related to these thorny processes. It is also possible and even preferential that the wedge further comprises, as mentioned before, locking-unlocking means 70. These locking-unlocking means 70 may be constituted in different ways. For example, as illustrated in the figures, they may consist of a protruding part on one of the following elements: a tab 40, the body 10, and a recessed part on the other element, this recessed portion may be the space between the branches of the first U 11, 12. Can also be provided means constituted by the fact that the shaft 20 is secured under tension in tension with the at least one lug 40 or both tabs 40, to tend to press force this tab or both legs against the body 10. It is also possible that the wedge has means 80 for holding the two branches 11, 12 spaced apart from each other after the leg has taken a position as shown in Figure 2, and thus avoid the distraction is canceled for example in time. This element also makes it possible, particularly when it is positioned very close to the shaft 20, to prevent this shaft from coming out of its bearing 30.

These means 80 for maintaining the distraction may consist of a rack with non-return ratchets, as evoked schematically in broken lines in FIG. 2. FIGS. 3 to 5 show a second embodiment of the wedge according to FIG. invention having structural features in addition to those defined above. In this second embodiment, the body 10 has a slot 100 made in each of the two branches 11, 12 of the first U to define, in each of them, two portions of branches 11-2-1, 11-2-2 and 12-2-1, 12-2-2.

This slot, open on three sides, is furthermore made in a plane forming a non-zero angle with respect to the plane of the first U, preferably preferably a right angle, and so as to form, in the body 10, a second U ( perpendicular to the first U in the preferred case of the right angle mentioned above) whose base is common with the base 13 of the first U. The tab 40 is secured to the shaft 20 so that it is able to rotate in the slot 100, the slot 100 and the lug 40 being arranged so that when the shaft 20 passes from its first position P1 to its second position P2, the lug 40 tends to move the two portions 112-1, 11 apart. -2-2; 12-2-1, 12-2-2 of at least one of the two branches 11, 12, preferably of the two branches. According to a preferred embodiment, at least a portion of the flat tab 40 is frustoconical (or similar as illustrated), the large base of the frustoconical shape being integral with the shaft 20 and the width of at least a portion of this frustoconical shape which is able to penetrate the slot 100 being between the minimum and maximum values of the width of this slot 100, in order to obtain its spacing. With this second embodiment, the wedge may also comprise one or two other tabs 40, for example on the two opposite outer faces of the body 10. However, it should be emphasized that the bone wedge according to the first embodiment, FIGS. and 2, while joining two bone portions 01, 02, to distract them relative to each other. As for the bone wedge according to the second embodiment, FIGS. 3 to 5, it allows, in addition, to increase the support polygon on which the two bone portions 01, 02 rest, and thus to ensure a even greater stability of the connection between these two portions of bone. The distraction and increase of the lift polygon are schematically illustrated in Figure 5 where they are indicated by the two arrows f1, f2. In the case of distraction and augmentation of the lift polygon, the means for mounting the one or both outer legs 40 in cooperation with the shaft 20 are constituted by means which allow the legs both to be driven. in rotation with the shaft 20 and sliding in translation relative to the axis 31 when the two portions 11-2-1, 11-2-2; 12-2-1, 12-2-2 of the two branches 11, 12 deviate to increase the levitation polygon, as described above. The use and implantation of the bone wedge according to the invention will not be described here because they are deduced without any difficulty from the description of this wedge made above and from the contents of documents dealing with similar wedges of the prior art, and even intervertebral distracting cages.

Claims (13)

REVENDICATIONS1. Bone block capable of being interposed between two bone portions (01, 02), characterized in that it comprises: a body (10) substantially in the shape of a first U having two branches (11, 12) and a base (13) connecting two first ends (11-1, 12-1) of these branches, - a cylindrical shaft (20) having a cross section whose thicknesses respectively defined along two axes (X, Y) forming between them a non-zero angle, are of different values, - a bearing (30) defined according to a given axis of rotation (31), said bearing being formed in the opposite faces (14, 15) of the two branches (11, 12), said cylindrical shaft (20) being rotatably mounted in said bearing (30) between said two legs (11, 12) and in contact therewith, - at least one substantially flat lug (40), - means for mounting said tab (40) in cooperation with said shaft (20) so that the plane of said tab makes with said rotational axis (31) a non-rotational angle ul and that said tab is rotated with that of said shaft, and - means (50) for controlling the rotation of said cylindrical shaft (20) in said bearing (30) relative to said body (10). 2. Shim according to claim 1, characterized in that said tab (40) has a shape such that: (i) when said shaft (20) is in a first position (P1) relative to said body (10), in which its largest thickness is defined along a line substantially parallel to the opposite faces (14, 15) of the two branches, the tab is at least largely inscribed in the cross section of the body defined in the plane of the first U, (ii) when said shaft (20) is in a second position (P2) with respect to said body (10), wherein its largest thickness is defined along a straight line substantially perpendicular to the opposite faces (14, 15) of two branches, the tab overflows the cross section of the body defined in the plane of the first U. 3. Shim according to one of claims 1 and 2, characterized in that said cylindrical shaft (20) has a substantially elliptical cross section. 4. Shim according to one of claims 1 to 3, characterized in that it comprises locking-unlocking means (70) which cooperate with said lug (40) and said body (10) when said shaft (20) is at least in its second position (P2). 5. Wedge according to one of claims 1 to 4, characterized in that said tab (40) is located in one of the following ways: on one side of said body (10), in a cavity made in said body . 6. Shim according to one of claims 1 to 5, characterized in that the means (50) for controlling the rotation of said shaft (20) in said bearing (30) relative to said body (10) are constituted by at least one of the following means: (i) means for printing, to said shaft (20), a rotational force transmitted in a direction substantially parallel to its axis of rotation (31), (ii) means for printing, said shaft (20), a rotational force transmitted in a direction substantially perpendicular to its axis of rotation (31). 7. Shim according to one of claims 1 to 6, characterized in that it comprises at least two tabs (40) substantially planar and means for securing the two said tabs (40) at both ends of said shaft ( 20) emerging from said body (10) on two opposite sides thereof. 8. Wedge according to claim 7, characterized in that the planes of said legs are, with said axis of rotation (31), an angle substantially equal to ninety degrees. 9. Wedge according to one of the preceding claims, characterized in that the locking-unlocking means (70) are constituted by the fact that said shaft (20) is secured under tension in tension with the at least one leg (40). ), to tend to press force said tab against said body (10). 10. Shim according to one of the preceding claims, characterized in that the two legs (11, 12) and the base (13) connecting two first ends (11-1, 12-1) of said branches are made of one piece. 11. Shim according to one of the preceding claims, characterized in that it comprises means (80) for holding the two branches (11, 12) spaced apart when said shaft (20) is at least in its second position (P2). 12. Shim according to one of claims 1 to 6, characterized in that said body (10) comprises a slot (100) formed in each of the two branches (11, 12) to define, in each of them, two portions of branches (11-2-1, 11-2-2, 12-2-1, 12-2-2), said slot being furthermore made in a plane forming a non-zero angle with respect to the plane of the first U , optionally at a right angle, and so as to form, in said body (10), a second U whose base is common with the base (13) of the first U, said tab (40) being integral with said shaft (20) such that it is pivotable in said slot (100), said slot (100) and said tab (40) being arranged so that when said shaft (20) pivots between two positions, said tab (40) has tend to separate the two portions (11-2-1, 11-2-2, 12-2-1, 12-2-2) of at least one of the two branches (11, 12). 13. Wedge according to claim 12, characterized in that at least a portion of said tab (40) is frustoconical in shape, the large base of the frustoconical shape being integral with said shaft (20) and the width of the at least a part of this frustoconical shape which is able to penetrate into said slot (100) being between the minimum and maximum values of the width of this said slot.