FR2880795A1 - Intervertebral cage for treating degenerative vertebral rachis, comprises disc shape spacer with faces of opposite bases, side wall which connects the base faces, blade and an element to move the blade compared to a insole of wall parts - Google Patents

Abstract

The spacer (1) is placed between the faces in regards to vertebral bodies. The blade (20) has two ends (25, 26) and is arranged between parts (6, 7) of the sidewall (5) and sides of the spacer. The blade comprises shoulders inserted into the vertebral bodies (50, 51) and assembled in co-operation with insole of the blade ends. The angle between the blade and the shoulders is 0-180[deg]. The shoulders are constituted by hook comprising concave open/closed loop. An auxiliary shoulder has screw perpendicular to the blade rotation plane. The auxiliary shoulder is assembled in co-operation with the shoulder in the shape of hook and formed in general plane of the hook with an angle 90[deg]. The interior of the concave loop is constituted by an opening which is tapped.

Description

IMPROVED BLADE-IMPROVED INTERVERTEBRAL CAGE

  The present invention relates to an improvement in the intervertebral cage such as that described in FR-A-2 841 123 and which finds a particularly advantageous application, but not exclusively, for the treatment of the degenerative spine.

  The cage described in this document essentially comprises a substantially disk-shaped spacer comprising two substantially flat and parallel opposed base faces and a lateral wall connecting the two base faces, this lateral wall comprising two opposite parts, said spacer being capable of being arranged between the facing faces of the two vertebral bodies respectively of two consecutive vertebrae replacing the damaged disc between these two vertebrae, the two base faces of the spacer being adapted to be placed in contact at least partially with the two vertebral bodies, at the at least one blade having two opposing ends shaped in a bevel, and means for moving the blade relative to a first of the two side wall portions so that the blade is adapted to take two positions: a first position in which the blade is entirely located in the space between the first and second planes containing the two base faces of the spacer, and a second position in which the two opposite ends of the blade emerge on either side of said space, the two opposite ends of the blade each having a shoulder, these two shoulders. being respectively made so that they are substantially contained in planes parallel to the planes of the two opposite base faces of the spacer and respectively sunk into the two vertebral bodies when the blade is in its second position.

  This cage gives very good results but, in its desire to always improve the products in the medical field, the Applicant proposes to carry out a development.

  More specifically, the subject of the present invention is an intervertebral cage for the treatment of the degenerative spine, comprising: a substantially disk-shaped spacer comprising two opposite substantially planar and parallel base faces and a lateral wall connecting the two base faces, this side wall having two opposite parts, said spacer being adapted to be disposed between the facing faces of the two vertebral bodies respectively two consecutive vertebrae replacing the damaged disc between these two vertebrae, the two base faces of the spacer being adapted to be placed in at least partial contact with the two vertebral bodies, - at least one blade, said blade having two opposite ends shaped as a bevel, and means for moving said blade relative to a first of the two side wall portions so that the blade is able to take two 10 positions: * a first posit ion in which the blade is entirely located in the space between the two first and second planes containing the two base faces of the spacer, and * a second position in which the two opposite ends of said blade emerge from part and other said space, the two opposite ends of said blade each having a shoulder, these two shoulders respectively being made so that, when the blade is in its second position, their general directions are substantially contained in planes parallel to the planes of the two opposite base faces of the spacer, the two said shoulders being respectively driven into the two vertebral bodies when said blade is in its second position, characterized in that the two general directions respectively of the two shoulders are between them an angle between zero degrees and one hundred and eighty degrees, limit values included.

  Other features and advantages of the invention will emerge in the course of the following description given with reference to the accompanying drawings for illustrative but not limiting purposes, in which: FIGS. 1 and 2 show, in schematic form, a first embodiment of FIG. the improved intervertebral cage according to the invention, FIG. 1 being a perspective view and FIG. 2 a side view, and FIGS. 3 and 4 are schematic representations of a second embodiment of the intervertebral cage according to FIG. Figure 3 is a perspective view and Figure 4 is a side view.

  It is first of all specified that, in the figures, the same references designate the same elements, whatever the figure on which they appear and whatever the form of representation of these elements. Similarly, if elements are not specifically referenced in one of the figures, their references can be easily found by referring to the other figure.

  It is also stated that the figures essentially represent two preferred 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.

  Finally, it is stated that when, in the present description, an expression alone defines, without any particular specific mention concerning it, a set of structural characteristics, [for example E = E (p, s, ...)], these characteristics can be taken, for the definition of the object of the requested protection, when technically possible, either separately, [eg s, and / or i, and / or p, ...], or in full combination and / or partial, [e.g. E (s,, p), and / or E (s, i), and / or 1 ('r, p), and / or E (s, p)].

  This having been specified, the present invention relates to an improvement to an intervertebral cage such as that described in FR-A-2 841 123 for, in particular, the treatment of the degenerative spine.

  This improved intervertebral cage essentially comprises a substantially parallelepiped shaped disc-shaped spacer 1 advantageously comprising a hollow recess (or several) in which it is possible to place a bone graft.

  This disc comprises two faces of opposite bases 3, 4 substantially flat and parallel to each other and a side wall 5 connecting the two faces of bases. In a particularly advantageous form, this side wall comprises for example two opposite parts 6, 7.

  The spacer 1 is able to be arranged between the facing faces 8, 9 of the two vertebral bodies 10, 11 respectively of two consecutive vertebrae, replacing the damaged disc which was located between these two vertebrae, the two base faces 3, 4 of the spacer 1 being adapted to be placed in contact at least partially facing faces 8, 9 of the two vertebral bodies.

  The cage further comprises at least one blade 20 and means 21 for moving this blade relative to a first of the two opposite parts of the side wall 5, in this case at least the portion 6 in FIG. 1, so that the blade can take two positions: a first position in which the blade is entirely located in the space between the first and second planes containing the two base faces 3, 4 of the spacer 1, and a second position as that which is illustrated in the four figures, in which the two opposite ends 25, 26 of the blade emerge on either side of this space.

  In addition, advantageously, the two ends 25, 26 of the blade 20 are bevelled so as to be able to penetrate more easily into the bone of the vertebral bodies 10, 11 in the manner of a knife blade or the like. It should be noted that this beveled shape has not been specifically shown in the figures, essentially for the purpose of simplifying the drawings, but it is well represented in particular in the document mentioned in the preamble of the present description.

  In an advantageous embodiment, the means 21 defined above, for moving the blade 20 relative to a first 6 of the two opposite side wall portions so that the blade is able to learn two positions, comprise for example a shaft mounted in rotation along an axis 31 in the first portion 6 of the side wall 5, and means for mounting the blade in cooperation with one end of the shaft.

  This shaft is used to transmit the command to move the blade 20 from its first position to its second position, and reciprocally if it is for example necessary to remove the intervertebral cage after it has been implanted.

  The means for rotating, by rotation, the blade 20 from its first position to its second position and vice versa, may be constituted by protruding or recessed portions of polygonal shape made at the end of the shaft on the part of the side face 6, with which can cooperate ancillary substantially identical to conventional tools that are commonly known as tube wrenches, screw spindles or the like.

  The cage may also include means for keeping the blade in its second position and preventing it from returning to its first position under the effect of any constraint whatsoever which would be exerted by the patient himself, while allowing him to return to this first position under the effect of external forces exerted, for example, using an ancillary instrument.

  According to an important characteristic of the invention, the two opposite ends 25, 26 of the blade emerging on either side of the space when the blade 20 is in its second position, each comprise a shoulder 41, 42, these two shoulders being respectively made so that their general directions, when the blade 20 is in its second position, are substantially contained in planes parallel to the planes of the two opposite faces of bases 3, 4 of the spacer, and respectively sunk in the two vertebral body 10, 11 when the blade is in its second position.

  According to a feature of the invention, the two general directions respectively of the two shoulders 41, 42 are between them an angle between zero degrees and one hundred and eighty degrees, including limit values.

  In this way, when the blade 20 is in its second position, its two opposite ends 25, 26 with their respective shoulder 41, 42 are implanted in the bone of the vertebral bodies 10, 11 and simultaneously provide two functions, namely: prevent the sliding of the cage along the axis 31 and oppose the spacing of the two vertebral bodies 10, 11 perpendicularly to the same axis 31. The blade 20 therefore plays a staple function that the blade cages of the prior art had not, apart from that described in the document referenced above.

  The blade 20 may be substantially flat, as illustrated in the figures, or curved or equivalent, but as a whole has a general shape defined in a plane Pr substantially perpendicular to the axis 31.

  The shoulders 41, 42 may be made in different ways. Two of the various possible embodiments are diagrammatically shown in FIGS. 1 to 4.

  In the embodiment illustrated in FIGS. 1 and 2, at least one of the two shoulders 41, 42, and advantageously both, is constituted by a first screw advantageously with a bone thread 50, 51 mounted in cooperation with a first two ends 25, 26 of the blade 20, for example through an orifice 125, 126 formed in an end 25, 26 of the blade. This screw is a double shoulder on both sides of the blade and allows to secure the end of the blade, and thus the cage as a whole, to the vertebra body.

  In the embodiment according to FIGS. 3 and 4, at least one of the two shoulders 41, 42, and advantageously both, is constituted by a hook 52, 53 comprising a concave loop 54, 55, the general plane of the hook. being substantially contained in the plane of rotation Pr of the blade 20.

  Of course, as illustrated in Figures 3 and 4, the two ends 25, 26 of the blade each comprises a hook, which gives the blade as a whole an "S" shape.

  In the case of this last embodiment, the cage may further comprise an auxiliary shoulder 60, 61 mounted in cooperation with the hook-shaped shoulder 52, 53, this auxiliary shoulder forming with the general plane Pr hook or the blade 20 at an angle substantially equal to ninety degrees. In this way, one end of the blade has two shoulders forming between them an angle of ninety degrees.

  It is even advantageous for this auxiliary shoulder 60, 61 to consist of a second screw advantageously with a bone thread 70, 71, this second screw being capable of being implanted in a direction substantially perpendicular to the plane of rotation Pr while passing through the concave loop. 54, 55. According to this structure, the end of the blade has in fact three shoulders arranged at zero, ninety and ninety degrees relative to each other and defining a shape in "T" which ensures even better anchoring in the vertebral body.

  The concave loops 54, 55 illustrated in FIGS. 2 and 3 are open, but they can be closed, as in the embodiment according to FIGS. 1 and 2, in which the orifices 125, 126 made at the two ends of the blade 20 constitute in fact inside the two loops.

  It is further specified that the interior of at least one concave loop 54, 55, if not advantageously the interior of the two, constitutes one of the orifices 125, 126 defined above, and that, to ensure a still anchoring better, it is possible that this hole is threaded, for example at the same pitch as the screws 50, 51 and / or 70, 71 so that one of these screws can be screwed into this threaded hole.

Claims (1)

8 claims   An intervertebral cage for degenerative spine treatment, comprising: a substantially disk-shaped spacer (1) having two substantially plane and parallel opposing base faces (3, 4) and a side wall (5) connecting the two faces of the spine; bases, this side wall having two opposite parts (6, 7), said spacer being adapted to be disposed between the facing faces (8, 9) of the two vertebral bodies (10, 11) respectively of two consecutive vertebrae replacing the disc damaged between these two vertebrae, the two base faces of the spacer being adapted to be placed in at least partial contact with the two vertebral bodies, - at least one blade (20), said blade having two opposite ends (25, 26) beveled, and means (21) for moving said blade relative to a first (6) of the two sidewall portions so that the blade is adapted to take two positions: * a first position in which the blade is entirely located in the space between the first and second planes containing the two base faces (3, 4) of the spacer (1), and * a second position in which the two opposite ends (25, 26) of said blade (20) emerge on either side of said space, the two opposite ends (25, 26) of said blade each having a shoulder, these two shoulders (41, 42) being respectively made of so that when the blade (20) is in its second position, their general directions are substantially contained in planes parallel to the planes of the two opposite base faces (3, 4) of the spacer, the two said shoulders being respectively depressed in both vertebral bodies when said blade (20) is in its second position, characterized in that the two general directions respectively of the two shoulders (41, 42) are between them an angle between zero degrees and one hundred and eighty degrees, including limit values.   2. Intervertebral cage according to claim 1, characterized in that at least one of the two shoulders (41, 42) is constituted by a first screw (50, 51) mounted in cooperation with a first of the two ends (25). , 26) of said blade (20).   3. Intervertebral cage according to one of claims 1 and 2, characterized in that at least one of the two shoulders (41, 42) is constituted by a hook (52, 53) having a concave loop (54, 55), the general plane of said hook being substantially contained in the plane of rotation (Pr) of said blade.   4. Intervertebral cage according to claim 3, characterized in that it comprises an auxiliary shoulder (60, 61) mounted in cooperation with said hook-shaped shoulder (52, 53), said auxiliary shoulder forming with the general plane ( Pr) of the hook an angle substantially equal to ninety degrees.   5. intervertebral cage according to claim 4, characterized in that said auxiliary shoulder (60, 61) consists of a second screw (70, 71), said second screw being adapted to be implanted in a direction substantially perpendicular to the plane rotating (Pr) the blade, and passing through the concave loop (54, 55).   6. intervertebral cage according to one of claims 3 to 5, characterized in that said concave loop (54, 55) is an open loop.   7. Intervertebral cage according to one of claims 3 to 5, characterized in that said concave loop (54, 55) is a closed loop.   8. Cage according to one of claims 3 to 7, characterized in that the interior of at least one concave loop (54, 55) constitutes an orifice (125, 126), said orifice being tapped.