Intervertebral Cage
The intervertebral cage addresses manufacturing costs and anchoring issues by using a translational motion mechanism to enhance secure fixation to vertebrae, reducing costs and increasing anchor points.
Patent Information
- Application Number
- FR2016000122
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2016-01-25
- Publication Date
- 2025-07-25
- Estimated Expiration
- 2036-01-25
AI Technical Summary
Existing intervertebral cages are expensive to manufacture and lack sufficient anchor points for secure fixation to vertebrae.
The intervertebral cage features a body with flat parallel base faces and a side wall, incorporating an element that moves between two positions via translation, controlled by means that transform rotational motion into translational motion, allowing enhanced anchoring through multiple points.
This design reduces manufacturing costs and provides improved anchoring by increasing the number of anchor points, facilitating secure fixation to vertebrae.
Smart Images
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Abstract
Description
The present invention relates to intervertebral (or intersomatic) cages capable of being interposed between two vertebrae, replacing the intervertebral disc originally located between these two vertebrae, of the type comprising an element having the general shape of a substantially cylindrical disc and means for locking this disc with at least one of the two vertebrae by means of pivoting blades capable of being anchored in the bony parts of the vertebrae. There is in fact known such an intervertebral cage which essentially comprises a body capable of being interposed between two vertebrae, this body comprising two opposite base faces which are substantially flat and parallel (or equivalent) and a side wall connecting the two base faces, at least one element such as a blade, and means for mounting this at least one blade in rotation relative to the body between at least a first position and a second position, the first position being that in which it is entirely contained in the volume between the two planes defined by the two substantially flat faces and the second position being that in which at least a part of the blade emerges from the volume so that its ends are planted in the bony part of the vertebrae. Such an embodiment of an intervertebral cage with at least one blade is for example described and illustrated in EP-A-1 674 053 and FR-A-2 846 876. These achievements are satisfactory but are relatively expensive to manufacture industrially and, in addition, do not allow a large number of anchor points to be obtained. Also, the present invention aims to produce an intervertebral cage which makes it possible to largely overcome the disadvantages of the intervertebral cages known from the prior art. More specifically, the present invention relates to an intervertebral cage comprising: • a body capable of being interposed between two vertebrae, said body comprising two opposite base faces which are substantially flat and parallel and a side wall connecting the two base faces, • at least one element, • means for mounting said element in movement relative to said body between a first position and a second position, the first position being that in which said element is substantially contained in the volume comprised between the two planes defined by the two substantially planar base faces of the body and the second position being that in which at least a part of said element emerges from said volume, and • means for controlling the movement of said element between said first and second positions, characterized in that • the means for mounting said element in displacement between the first and second positions are constituted by means for mounting said element at least in translation between these two said positions, and that • the means for controlling the movement of said element between said first and second positions are constituted by means for controlling the translation of said element. Other characteristics and advantages of the invention will appear during the following description given with reference to the attached drawings for illustrative but in no way limiting purposes, in which: Figure 1 represents, in side view, a schematic diagram of the intervertebral cage according to the invention, Figures 2 and 3 represent, in schematic form and respectively in top and side view, a preferred embodiment of the intervertebral cage according to the invention, and Figures 4, 5 and 6 respectively represent, in schematic form and in side view, three other embodiments of a part of the intervertebral cage according to the invention. It is first specified that: • in the figures, the same references designate the same elements, regardless of the figure in which they appear and regardless of the form of representation of these elements; similarly, if elements are not specifically referenced in one of the figures, their references can be easily found by referring to another figure, • the figures represent five embodiments of the object according to the invention, but there may be other embodiments which meet the definition of this invention, • 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 comprises several elements of identical function and if, in the description, it is not specified that the object according to this invention must necessarily comprise a particular number of these elements, the object of the invention may be defined as comprising “at least one” of these elements. • when in this description, an expression defines on its own, without any 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 this is technically possible, either separately, or in total and / or partial combination. • in this description, if the adverb "substantially" is associated with a qualifier of a given means, this qualifier must be understood in the strict or approximate sense. With reference to the appended figures, and more particularly to figure 1, the present invention relates to an intervertebral cage comprising a body 10 capable of being interposed between two vertebrae V1, V2, this body comprising two opposite base faces 11, 12 substantially flat and parallel (or similar) and a side wall 13 connecting the two base faces, at least one element 20, means for mounting this element moving relative to the body 10 between a first position P1 (in solid lines in FIG. 1) and a second position P2 (in broken lines in FIG. 1), the first position P1 being that in which this element is substantially preferably entirely contained in the volume 14 comprised between the two planes defined by the two substantially planar base faces 11, 12 of the body 10 and the second position P2 being that in which at least a part 21 of the element 20 emerges from this volume, and means for controlling the movement of this element 20 between the first and second positions P1, P2. According to a characteristic of the invention, the means for mounting the element 20 in displacement between the first P1 and second P2 positions are constituted by means for mounting the element at least in translation between these two positions P1, P2, and the means for controlling the displacement of this same element between the first and second positions are constituted by means for controlling its translation. According to an advantageous embodiment, as illustrated in the attached figures, the means for controlling the translation of the element 20 are constituted by means 50 for transforming a rotational movement into a translational movement. Thus, preferably, this element 20 is mounted in an orifice 22 which opens onto at least one of the two base faces 11, 12 of the body 10, and the means 50 for transforming a rotational movement into a translational movement comprise a hole 51 made in the body 10 and opening onto the side wall 13, this hole being made so that it has a common portion 52 with the orifice 22 and that the axes 57, 28 respectively of this hole and of the orifice make a non-zero angle between them, optionally a right angle, the axis 57 of the hole 51 preferably being parallel to the plane of the two base faces 11, 12. It is specified that the axis 28 of the orifice 22 can be rectilinear, as in the embodiments illustrated in figures 1, 2 and 3, but also rectilinear and curved, figure 4, or even totally curved figure 6, the element 20 then being produced according to this shape of the orifice, namely rectilinear-rigid as with the embodiments according to figures 1, 2, 3, 5, rigid-curved as with the realization according to figure 6, flexible-rigid as with the realization according to figure 4. The means 50 for transforming a rotational movement into a translational movement further comprise a driving shaft 53 mounted in rotation relative to the body 10 in the opening 51, a rack 54 comprising two sets of teeth, a first rectilinear set of teeth 55 mounted in cooperation with the element 20 and a second circular set of teeth 56 complementary to the first set of teeth 55, this second set of teeth being mounted in cooperation with the driving shaft 53, these two sets of teeth being mounted in gear cooperation so that the rotation of this driving shaft 53 causes the translation of the element 20 in the orifice 22 so that, for example as illustrated in FIG. 1, this element 20 passes from the position P1 to the position P2 emerging from the body 10, and comes to be inserted into the bony part of the vertebra V1 which is in contact with the face 11 on which the orifice 22 emerges. According to one embodiment, the cage according to the invention comprises, in addition to the means for controlling the translation of the element 20, means for controlling the rotation of this element around its longitudinal axis 23. In this case, according to an advantageous embodiment, the means for controlling the element 20 in translation and the means for controlling its rotation around its longitudinal axis 23 are combined means 60. These combined means may comprise a thread made on the side wall of the element 20, the orifice 22 then being tapped in a manner complementary to this thread, and means for exerting a thrust force on this element, for example a lever rod. In this case, the element 20 will be animated by two movements at the same time, namely in translation along its longitudinal axis 23 and in rotation around this same axis 23. However, according to a preferred embodiment, figure 5, these combined means 60 for obtaining both the translation and the rotation of the element 20 are constituted by a driving shaft 53 mounted in rotation relative to the body 10 in a bore 51 made so that it has a portion common 52 with the orifice 22 and that the axes 57, 28 respectively of this opening 51 and of the orifice 22 make between them a non-zero angle, optionally right, and a rack 54. In this case, the rack comprises two sets of teeth, a first helical set of teeth 55 mounted in cooperation with the element 20 and a second helical set of teeth 56 complementary to the first set of teeth, mounted by winding around the driving shaft 53, and means for coupling these first and second helical sets of teeth so that the rotation of the driving shaft 53 causes both the translation and the rotation of the element 20 in the orifice 22. With the embodiment as illustrated in Figure 5, the element 20 is substantially cylindrical in revolution and can then very advantageously comprise a thread 29 (schematically represented in this Figure 5) produced on the external surface of at least its part 21 which is capable of emerging from the volume 14, this thread optionally preferably being self-tapping. According to another embodiment, as illustrated in Figure 4, the element 20 is made of a material which gives it both rigidity and flexibility, which allows it, as illustrated in this figure, to fit an orifice 22 which has curves. This embodiment is advantageous in the case, for example, of a body 10 of small thickness. Because it makes it possible to provide an element 20 which has a length greater than this thickness and which can then penetrate into the bony body of the vertebra by a sufficient quantity to ensure the anchoring of the body 10 in this vertebra. As illustrated in Figures 2 and 3, the cage may comprise several elements 20, and even more advantageously coupled two by two with a single driving shaft, the rotation of this shaft causing the simultaneous translation in two opposite directions of the two coupled elements. Likewise, because the element 20 is mounted in translation, it is possible, figure 5, to provide a conduit 24 made in this element so that it opens at least at the level of its part 21 which is capable of emerging from the volume 14, to allow the injection of a product promoting for example the solidification of the bone medium around the element 20. It is also possible to provide that the part 21 capable of emerging from the volume 14 is split to move apart when it enters the bone environment. Such a cage may further comprise a threaded hole made at the visible end of the driving shaft 53 and capable of receiving an ancillary tip. It may also be provided that this driving shaft is removably mounted in the bore 51 so that it can be removed from the body 10 after it has been used to translate (and pivot) the element(s) 20. When, as illustrated in Figure 2, this driving shaft 53 passes right through the body 10 which comprises a central cavity 100, a blade 110 or the like may also be provided which will be driven in rotation with this shaft to anchor itself in the bone medium, as with the embodiments of the prior art. The implantation and operation of the intervertebral cage according to the invention between two vertebrae V1, V2 can be easily deduced from the description of this cage given above and will therefore not be described further here. It will simply be noted certain advantages of this cage compared to similar cages of the prior art, which are consequences of its structure. In fact, its structure facilitates the construction of the cage and therefore reduces its cost. It also allows for better anchoring of the cage in the vertebrae between which it is implanted, by offering a greater number of possible anchoring points than with the cages of the prior art. Furthermore, in the case of the embodiment according to figure 4 with bodies 10 of relatively low thickness, the cage according to the invention allows easier, and therefore more controllable, adaptation of the quantity of penetration of the element 20, or elements 20, into the vertebrae.
Claims
CLAIMS 1. Intervertebral cage comprising: • a body (10) capable of being interposed between two vertebrae (V1, V2), said body comprising two opposite base faces (11, 12) which are substantially flat and parallel and a side wall (13) connecting the two base faces, • at least one element (20), • means for mounting said element in displacement relative to said body (10) between a first position (P1) and a second position (P2), the first position (P1) being that in which said element is substantially contained in the volume (14) comprised between the two planes defined by the two substantially planar base faces (11, 12) of the body (10) and the second position (P2) being that in which at least a part (21) of said element (20) emerges from said volume, said means for mounting said element (20) in displacement between the first (P1) and second (P2) positions being constituted by means for mounting said element (20) at least in translation between these two said positions (P1, P2), and • means for controlling the movement of said element (20) between said first and second positions, said means for controlling the movement of said element (20) between said first and second positions being constituted by means for controlling the translation of said element, characterized in that said element (20) comprises a conduit (24) opening at least at the level of its said part (21) which is capable of emerging from said volume (14).
2. Intervertebral cage according to claim 1, characterized in that the means for controlling the translation of said element (20) are constituted by means (50) for transforming a rotational movement into a translational movement.
3. Intervertebral cage according to claim 2, characterized in that said element (20) is mounted in an orifice (22) which opens onto at least one of the two base faces (11, 12) of the body (10).
4. Intervertebral cage according to claim 3, characterized in that the means (50) for transforming a rotational movement into a translational movement comprise: • a breakthrough (51) made in said body (10) and opening onto the side wall (13), said breakthrough being made so that it has a common portion (52) with said orifice and that the axes respectively of this breakthrough and of said orifice make a non-zero angle between them, optionally right angle, • a driving shaft (53) mounted in rotation relative to said body (10) in said opening (51), and • a rack (54) comprising two sets of teeth, a first rectilinear set of teeth (55) mounted in cooperation with said element (20) and a second circular set of teeth (56) complementary to said first set of teeth (55), said second set of teeth being mounted in cooperation with said driving shaft (53), these two sets of teeth being mounted in gear cooperation so that the rotation of said driving shaft (53) causes the translation of said element (20).
5. Intervertebral cage according to claim 3, characterized in that it further comprises means for controlling the rotation of said element (20) around its longitudinal axis (23).
6. Intervertebral cage according to claim 5, characterized in that the means for controlling said element (20) in translation and the means for controlling the rotation of said element around its longitudinal axis (23) are combined means (60).
7. Intervertebral cage according to claim 6, characterized in that the combined means (60) for obtaining the translation and rotation of said element (20) comprise: • a driving shaft (53) mounted in rotation relative to said body (10) in a bore (51), said bore being made so that it has a common portion (52) with said orifice (22) and that the axes respectively of this bore (57) and of said orifice make a non-zero angle between them, optionally right angle, and • a rack (54) comprising two sets of teeth, a first helical set of teeth (55) mounted in cooperation with said element (20) and a second helical set of teeth (56) complementary to the first set of teeth, mounted by winding around said driving shaft (53), and means for coupling these first and second helical sets of teeth so that the rotation of said driving shaft (53) causes both the translation and the rotation of said element (20) in said orifice (22).
8. Intervertebral cage according to one of claims 5 to 7, characterized in that said element (20) is substantially of cylindrical shape of revolution and comprises, on the external surface of its part (21) which is capable of emerging from said volume (14), an optionally self-tapping thread.