EP2293742A1

EP2293742A1 - Intersomatic cage

Info

Publication number: EP2293742A1
Application number: EP09754190A
Authority: EP
Inventors: Michael Perisic
Original assignee: Medtech Research
Current assignee: CARPE CONSULTANTS SARL
Priority date: 2008-05-26
Filing date: 2009-05-26
Publication date: 2011-03-16
Also published as: US9289314B2; US20170000620A1; US9421114B2; WO2009144562A1; AU2009252835A1; US20110230968A1; US11103361B2; US20150297358A1; US20210259851A1; US20190000639A1

Abstract

The invention relates to an intersomatic cage comprising a body (3) and a part (2) that is designed to dilate the intersomatic space between two vertebrae (8, 8') by rotating the cage so that the cage (1) can be inserted into the space. The body (3) has a prism shape with a substantially planar upper surface (6) which can bear against the superior vertebral endplate (8) and a substantially planar lower surface (6') which can bear against the inferior vertebral endplate (8').

Description

INTERSOMATIC CAGE

The present invention relates to the medical field and more particularly to an inter-somatic cage including insertion tab.

Technical area

Certain pathologies of the spine, including degenerative disc and facet diseases and dislocations of vertebrae, compromise the support capacity of the spine and the distribution of the load.

The treatment of these pathologies in their advanced stages uses different stabilization systems by intra-discal implants such as intersomatic cages, coupled or not with extra-discal implants, which notably combine the use of vertebral screws and plates or stems. .

These intradiscal implant systems have significantly improved the treatment of pathologies of the spine, by restoring the intervertebral space, which leads to the decompression of nerve roots and the acceleration of bone fusion of vertebrae. adjacent to each other.

These intersomatic cages are of several types: the first category includes threaded cages, which are essentially cylindrical in shape, and which are screwed into the intervertebral space. WO 03/009786 describes for example a cage of this type comprising an insertion tab of rectangular shape, elliptical or oval, located at the front of the cage. The cross section of this tongue progressively increases along the longitudinal axis of the cage from its end to the threaded part of said cage, so as to allow the insertion of the latter into the inter-somatic space and then the expansion of this space by screwing the cage. The main disadvantage of this type of threaded cages lies in the fact that they do not reproduce a lordosis angle close to the natural angle of the segment.

Impaction cages constitute the second category, where the cage of mainly parallelepiped shape, is introduced between the vertebrae by the application of impacts. The disadvantage of these cages, is the difficulty of introducing into the intersomatic space, by posterior approach, after laminectomies and partial facectomies, or by transforaminal or lateral approaches, cages having a cross section of high height, to treat the vertebral segments where the natural sagittal position is substantially lordotic, especially when the natural angle to be restored is greater than 10 °. Expandable cage systems in situ have been developed to allow such heights to be obtained in the front part of the cages, but often at the expense of reduced strength, strength and stability.

The object of the present invention is therefore to provide an intersomatic cage in a single homogeneous body whose geometry has the merit of remedying these disadvantages.

Another object of the present invention is to provide a device for introducing the intervertebral cage into the intervertebral space.

According to the invention, this object is achieved thanks to an intersomatic cage comprising a body and a part intended to dilate the intersomatic space between two vertebrae by rotation of the cage in order to be able to introduce said cage through the effect of a thrust. The prism-shaped body having a substantially planar upper surface adapted to abut against the upper vertebrae plate and a substantially planar lower surface adapted to abut against the lower vertebrae plate. The advantage of the present invention lies in the fact that it allows the insertion of cages having a cross section of high height and whose upper and lower faces are inclined, particularly in the direction of the rear of the cage, to offer a lordosis angle close to the natural angle of the segment which may be substantially greater than 10 °, which is not possible for threaded cages inserted by posterior approach as described in WO03 / 009786.

In addition, compared with the state of the art, the invention also makes it possible to introduce a cage in parallelepiped shape or of trapezoidal cross-section in the intervertebral space without necessarily having to use impaction to introduce the body of the cage. , enough pressure to insert it.

The characteristics of the invention will emerge more clearly on reading a description of several embodiments given solely by way of examples, in no way limiting with reference to the schematic figures, in which:

Figure 1 shows a front perspective view of a cage having an insertion tongue oriented along a plane inclined at approximately 45 ° to the horizontal plane of the cage according to a first embodiment;

Figure 1a shows a front view of Figure 1, when the tongue is introduced into the intersomatic space slightly dilated;

Figure 1b shows a front view of Figure 1, after rotation of the cage of about 45 ° and complete expansion of the intersomatic space;

FIG. 2 represents a front perspective view of a side asymmetric cage for unilateral, transforaminal or lateral approaches, with an oblique central insertion tongue parallel to the upper surface of the cage according to a second embodiment; FIG. 2a shows a front view of a cage in lateral asymmetry according to an alternative embodiment with the insertion tongue introduced into the slightly expanded intersomatic space; Figure 2b shows a front view of the cage according to this variant, after rotation of said cage by an angle less than 45 °;

Figure 3 shows a perspective view of a cage having two insertion rods according to a third embodiment; Figure 4 shows a perspective view of a lateral asymmetric cage for trans-foraminal or lateral approaches with two insertion rods according to a fourth embodiment;

Figure 5 shows a perspective view of a cage with an insertion tongue whose side flanks are beyond the lateral sides of the cage body according to a fifth embodiment;

Figure 5a shows a front view of Figure 5, when the insertion tab is introduced into the slightly expanded intersomatic space;

Figure 5b shows a front view of Figure 5, after rotation of the cage with an angle β; Figure 6 shows a side view of two adjacent vertebrae and a side asymmetric cage adapted for trans-foraminal or lateral approaches according to a sixth embodiment;

Figure 7 shows a perspective view of a cage with two flaps according to a seventh embodiment; Figure 7a shows a perspective view of a cage with two bent rods according to an alternative embodiment;

Figure 8 shows a front perspective view of a cage having an oblique plane insertion tab and lateral fins on a portion of the body of the cage according to a ninth embodiment; Figure 8a shows a view similar to Figure 8 but with curved fins in a first embodiment;

Figure 8b is a perspective view of a cage with two opposed flaps projecting from the lateral sides of the body and extending along said sides according to a second alternative embodiment; Figure 9a shows a front perspective view of a cage whose end comprises two surfaces having a helical gradient slope according to a ^9th embodiment; Figure 9b shows a front view of Figure 9a, when the cage is in its final position, with filigree, the position of the cage at the time of engagement of its end in the intersomatic space;

Figure 9c shows a front view of a cage according to a first embodiment, when the cage is in its final position, with filigree, the position of the cage at the moment of engagement of its end in the intersomatic space

9d shows a front view of a cage according to a second variant of execution, when the cage is in its final position, with filigree, the position of the cage at the time of engagement of its end in the intersomatic space;

Figure 10a shows a front perspective view of a hybrid right cage according to a io ^th embodiment;

Figure 10b shows the same cage as in Figure 10a but in front left perspective;

Figure 10c shows a front view of Figure 10a;

Figure 11a shows a perspective view of an intervertebral cage with two removable inserter rods in accordance with a 11 ^th embodiment;

Figure 11b shows a perspective view of an intersomatic cage according to a first embodiment;

Figure 11c is a perspective view of a hybrid intersomatic cage according to a second alternative embodiment;

Figure 12 shows a perspective view of a cage with lamellae forming an integral part of an ancillary laying according to a - 2 ^nd embodiment;

Figure 12a shows a top view of the cage and ancillary laying in a first position;

Figure 12b shows a top view of a similar cage and a similar posture ancillary in a second position; Figures 12c and 12d show a top view of an arcuate form cage according to an alternative embodiment in two successive positions; Figure 13 shows a perspective view of a cage according to I3 ^th embodiment;

Figure 14 shows a perspective view of a cage according to aspects a ^14th embodiment; Figures 14a and 14b show a front view of the cage with removable flaps in a retracted and extended position. Figure 14c is a detailed perspective view of Figure 14a.

Realization of the invention

In the description of the different intersomatic cages that follows, reference will be made in particular to the horizontal plane of the cage that will be assumed in a plane parallel to the axial or transverse plane of the human body, this horizontal plane corresponding to the position of the cage in its length when it is found in its final position between two vertebrae.

According to the first embodiment of the invention, FIG. 1 illustrates an intersomatic cage for posterior / posterolateral approaches. This cage comprises a body 3 of a conventional form of impact cage, is essentially parallelepiped or a body 3 having a longitudinal section of trapezoidal shape. This body 3 has an upper and lower surface 6, 6 'intended to come into contact with the respective upper and lower vertebral trays. These two surfaces 6, 6 'are inclined with respect to a horizontal plane so as to obtain a body 3 whose height of the anterior side 7 is greater than the height of the posterior (not visible) side. These two surfaces 6, 6 'have between them an angle δ typically ranging from 4 ° to 15 °, or even higher, to allow a lordosis of the vertebrae of the segment. These surfaces 6, 6 'can be covered with crenellations to prevent migration in front of or behind the cage. Moreover, the body 3 of the cage may comprise a through-through 4 in the direction of the height so as to allow graft stuffing to promote bone fusion between the two adjacent vertebrae

This cage further comprises a portion 2 for expanding the intersomatic space between two vertebrae for the introduction of the intervertebral cage. Part 2, which we will here more commonly call insertion tab, has a substantially oblong cross-section of height H 'and width W. This part 2 is arranged perpendicular to the front side 7 of the cage body 3 and in a inclined plane forming an angle of about 45 ° with the horizontal plane of the cage so that said portion 2 extends in the direction of its height H 'along the diagonal of the front side 7 of the cage body 3 .

It goes without saying that the inclination of the tongue 2 may vary in an oblique plane having an angle preferably between 40 ° and 60 ° relative to the horizontal plane of the cage. According to FIG. 1, the height H 'of the tongue 2 is greater than the height of the highest section H of the body 3. According to FIGS. 1a and 1b, it can be seen that the dimensions of the tongue 2 make it possible to reduce significantly the angle of rotation necessary to expand the intersomatic space between the vertebrae 8, 8 'to introduce the entire cage body 3. Indeed, from Figure 1 b, the intersomatic space of height H "which is greater than the height H of the body 3 in its anterior part is obtained by a rotation of an angle β close to 45 ° This significantly reduces the forces of shear stresses F, F 'exerted between them by the two vertebrae 8, 8 'of the segment.The angle of rotation can also be greater than that required to obtain the height H ", especially for passing cages with high crenellated surfaces. The lateral flanks of the tongue 2 make it possible to insert and guide the body 3 in abutment against the two respective vertebral plates 8, 8 'along an inclined plane of the angle β in the intersomatic space before said body 3 reaches its final position and makes a slight counter-rotation under the effect of the compression of the vertebrae 8, 8 '. For the introduction of the cage, an instrument can be fixed by screwing the posterior side of the body 3. After the extraction of all or part of the intervertebral disc, and possibly after application of dilation candles in the intersomatic space, and then spacing nerve roots, the cage is implanted in five stages namely: introduction of the cage into the spinal canal; rotation; introduction / pressure of the insertion tongue 2 in the intervertebral space; counter-rotation; thrust of the cage in the intervertebral space. More specifically, the implantation steps are as follows: introduction of the cage into the spinal canal with its insert tongue 2 vertically. In contact with the front of the insertion tongue 2 with the vertebrae, the cage is turned at an angle substantially less than 90 ° to tilt the insertion tongue 2 to the horizontal which allows its insertion into the slightly dilated intervertebral space. The cage is then turned again by an angle less than 90 °, but in the opposite direction of the second step, which has the effect of expanding the intervertebral space by a height close to the height H ¹ of the tongue insertion 2 of the cage. This is then pushed, or, if necessary, impacted, within the intervertebral space, to its final position. The insertion tongue may be in a material different from that of the body, for example a resorbable material intended to disappear to give way to bone growth, or an osteoconductive material, responsible for promoting said bone growth.

FIG. 2, according to the second embodiment of the invention, represents an intersomatic cage for unilateral, trans-foraminal or lateral approaches, that is to say a cage which is inserted posterolaterally or laterally, and whose final position is situated in the anterior part of the intersomatic space, perpendicular to the sagittal plane. The instrumentation of an intervertebral segment with such a cage does not in principle require the introduction of a second cage. The particularity of this cage lies in the fact that it comprises a cage body 3 which is asymmetrical not in the sense of its length (as described in the first embodiment) but in that of its width. The lordosis angle δ ¹ sought for the final position vertebrae of the segment, is given, in this case, by the angle obtained by the extension of the upper and lower surfaces 6, 6 ¹ in the direction of their width. According to Figure 2, the cage comprises an insertion tongue 2 which is in a plane P parallel to a plane P 'in which is the upper surface 6 of the cage body 3. The tongue 2 is eccentric in a parallel plane at a horizontal plane halfway up the cage body 3.

In a variant shown in Figures 2a and 2b, the tongue 2 is in an oblique plane relative to the plane in which is the upper or lower surface of the body 3. This allows to extend the height H ¹ of the tongue of 2, which in turn reduces the angle of rotation β necessary for the sufficient expansion of the intersomatic space H "to pass the body 3 of the cage.This angle reduces correspondingly the forces of constraint of shear exerted by the vertebrae 8, 8 'of the segment between them, which can promote the maintenance of trajectories of the implant in the intersomatic space.

At the first contact of the insertion tongue 2 against the vertebrae 8, 8 ', (Figure 2a) the tongue is, if appropriate, directly introduced without prior rotation into the pre-expanded intersomatic space or, if necessary, after a slight rotation printed at the cage to align the tongue 2 in the plane of the intersomatic space. After complete insertion of the tongue 2, a rotation of approximately 45 ° is carried out (FIG. 2b), which has the effect of expanding the space by a height H "which is sufficient to make the body 3 pass to its cross-section. between the upper and lower faces 6, 6 ', the cage is then pushed or, if necessary, impacted, until the body 3 penetrates fully into the intersomatic space and is pushed into its final position, in the anterior part of said space Although according to Figure 2b the angle of rotation β is about 45 °, it can be lower or higher depending on the ratio between the height and the width of the cage (for example between 30 ° and 60 °) This cage can also be arched with respect to its longitudinal axis, in order to marry the anatomy of the vertebral body in its anterior part. According to a third embodiment of the invention, Figure 3 shows an intersomatic cage which comprises a cage body 3 of geometric shape similar to the cage body of the first two embodiments. Two rods 13, 13 'are mounted on the front side 7 of the body 3 in two opposite corners along a diagonal. These two rods 13, 13 'are oriented along an axis perpendicular to the front side 7 and have a length sufficient to be inserted sufficiently forward between two adjacent vertebrae and serve as a lever to expand the space by a rotational movement . Preferably, this length is between 6 and 7mm. The arrangement of these rods 13, 13 'makes it possible to obtain a technical effect similar to that obtained by the insertion tongue 2 according to the first embodiment when the cage is inserted into the intervertebral space.

This cage is introduced through the spinal canal in a horizontal plane of the body 3, or, if it is desired that the rods 13, 13 'are found in a vertical plane (for example to bypass nerve roots) the body will have to to be tilted in a plane between 40 ° and 60 ° according to the height-width ratio of the anterior side 7 of the cage body 3. As soon as the rods 13, 13 'touch one or the vertebrae of a segment, the cage is then tilted until the rods 13, 13 'are found in a horizontal plane (the body of the cage then being in an oblique plane between 40 ° and 60 ° according to the height-width ratio of the front side 7 of the body).

According to one variant, the two rods can be arranged relative to one another so as to be in a vertical, horizontal plane or in an oblique plane forming an angle with the horizontal plane of the cage other than 45 ° . The plane will be chosen according to the desire to limit or increase the angle of rotation and the force necessary for the sufficient expansion of the intersomatic space for the introduction of the body 3. The plane can pass on the median axis longitudinal of the body of the cage, or be located next to said axis, to increase or attenuate the cam effect of the body at the time of its rotation, one or the other of its sides. One or more median stems between both stems can be added. The cross section of the stems can obviously be of any shape, including square, oval, or obiongue.

According to a fourth embodiment of the invention, FIG. 4 represents a cage which differs from the cage according to the preceding embodiment by the geometric shape of the body 3 which is adapted for trans-foraminal or lateral approaches, that is to say that it is a cage intended to be positioned laterally in the intersomatic space. The body 3 of this cage is of geometric shape similar to that of the second embodiment (FIG. 2) and therefore has a lateral side 3 "higher than the other (3 '), whereas its front side 7 and posterior The rods 13, 13 'are mounted on the anterior side 7 of the cage body 3. These rods 13, 13' may form an integral part of the body, or they may be nested, crimped or screwed together. in said body by one of their ends, these rods may be of a material different from that of the body, for example a resorbable material intended to disappear to give way to bone growth, or an osteo-conductive material, responsible for promoting said bone growth.

According to a fifth embodiment, FIG. 5 represents an interbody caging for posterior / posterolateral approaches, which comprises, on the one hand, a cage body 3 of geometric shape that is preferably identical or similar to the cage body according to the first embodiment execution and other part, part 2, intended to expand the intersomatic space. This part 2, which will also be called insertion tongue, is arranged on the front side 7 of the body 3 of the cage. This tongue 2 extends beyond the lateral sides of this body 3 ', 3 ", so that the height H ^bιs of the tongue 2 is greater than the diagonal of the front side 7. The increased dimensions of this tongue 2 make it possible to to reduce the angle of rotation necessary for the expansion of the intersomatic space In other words, this tongue 2 reduces the necessary torsional force and the camming effect of the body The lateral edges of the tongue 2 are not necessarily parallel, but preferably they do not protrude relative to the upper and lower faces 6, 6 'of the cage body 3, once the cage is in its final position, so as not to disturb the contact with their respective vertebral vertebral plate.

Figure 5a shows the intersomatic cage just before a rotation is printed to the body 3 when the insertion tongue 2 is horizontal in the intersomatic space between the vertebrae 8, 8 '. FIG. 5b illustrates the end of the rotation of the cage by an angle β, with the interbody space dilated by a height H ", sufficient to push the entire body 3 of the cage into the intersomatic space, without the surfaces 6, 6 'rubbing the trays of the vertebrae 8, 8' because the height H of the cage at its highest transverse section is much smaller than the height H "of the intervertebral space required for the 3. This difference in height makes it possible to reduce the angle β as much as possible, and consequently the effect of the shear stress forces F, F ', the distraction force necessary for the expansion, as well as the cam effect of the body at the moment of rotation. Figure 5b shows that the expansion of the intervertebral space was obtained by a rotation of an angle β close to 45 °, even though the height of the body 3 is significantly larger than its width. This figure also shows that it is possible to apply significant crenellations profiles on the surfaces 6, 6 'without these impede the insertion of the cage.

According to a sixth embodiment, FIG. 6 represents a cage, for unilateral, transforaminal or lateral approaches, said cage being in its final position between two vertebrae 8, 8 '. This cage comprises an insertion tongue 2 arranged on the front side 7 of a cage body 3 of geometric shape similar to the cage body of the second embodiment. The particularity of this cage lies in the fact that, unlike the second embodiment, the tongue 2 extends beyond the lateral sides of the body 3, so as to obtain the advantages described in the fifth embodiment not for posterior / posterolateral approaches but for unilateral, transforaminal, and lateral approaches. According to a seventh embodiment, FIG. 7 represents an interbody cage for posterior / posterolateral approaches comprising a cage body 3 of geometric shape that is preferably identical or similar to the cage body according to the first embodiment and two flaps. , 19 'of trapezoidal cross section disposed on the front side 7 of the body 3 and oriented in a plane corresponding to that of the insertion tongue according to the preceding embodiment. The flaps 19, 19 'are respectively arranged close to a first and second corner of the front side 7 opposite along a diagonal. These flaps 19, 19 'comprise lateral flanks 20, 20' protruding beyond the edges of the anterior side 7 of the cage body 3. A variant as illustrated by FIG. 7a consists in substituting two rods 13, 13 'for the flaps. having a first segment oblique to the longitudinal axis of the body 3, and a second rectilinear segment oriented along another axis so that a portion of the rods 13, 13 'are located outside the vertical plane coinciding with the two lateral sides of the body 3.

According to an eighth embodiment, FIG. 8 illustrates an intersomatic cage similar to the cage described in the fifth embodiment, except that this cage further comprises, in the extension of the tongue 2, a fin 9, 9 arranged along each of the two lateral sides 3 ', 3 "of the cage body 3. The height H ^bιs of the tongue 2 is substantially greater than the height of the body 3 at its highest section, namely at its side 7. It goes without saying that the shape of the fins 9, 9 'and their dimensions may be arbitrary, for example, the width of the fins 9, 9' may increase or decrease along the longitudinal axis of the cage and / or extend the entire length of the lateral sides 3 ', 3 "of the body 3. The fins may also be non-continuous, and thus consist of several segments along the lateral sides.

Another example is illustrated in FIG. 8a which shows a cage comprising curved fins 9, 9 'so as to promote changes of trajectory in the intersomatic space and thus improve the positioning final of said cage. According to a variant not shown, these fins 9, 9 ¹ can also display a rectilinear shape inclined at any angle along the lateral sides, different from the plane formed by the tongue 2.

According to another example as represented by FIG. 8b, the cage comprises an insertion tongue combining certain characteristics of the intersomatic cages illustrated in FIGS. 7 and 8a.

According to a ninth embodiment of the invention, FIG. 9a represents an interbody caging for posterior / posterolateral approach, comprising a body 3 and a part 2 ^bιs intended to dilate the intersomatic space between two vertebrae for introduction. of the cage. The upper and lower faces 6, 6 'of the body 3 are not parallel, but positioned in an angle δ. This angle varies according to the cages, and is adapted to the desired lordotic angle as a function of the instrumented vertebral segment. This angle can typically range from 4 ° to 15 °, or even larger. The body may also have parallel upper and lower surfaces. The part 2 ^bιs is in the extension of the body 3 and comprises on the one hand, an upper and lower face 10, 10 '(Figure 9b) intended to come into contact with the vertebra respectively upper and lower intersomatic space and on the other hand two lateral faces 11, 11 '. These faces 10 '10', 11 and 11 'converge from the respective edges of the front side of the body 3 to a flat face 2n centered at mid-height and mid-width of said front side. This central face 2n has a shape similar to an insertion tongue as described in some of the preceding embodiments but of dimensions much smaller than the dimensions of the cage body 3. This flat face 2n stretches in the direction of the diagonal of the anterior side so as to form an angle β with the horizontal plane of the cage 3. The faces 10, 10 'are identical and are inclined and curved so as to reproduce the beginning of a helical gradient slope in order to to be able to transmit a rotation to the body 3 by simple pressure exerted on the posterior part of said body 3 when the central part 2n is arranged in the intersomatic space. According to FIG. 9b, the illustrated watermark cage represents the latter when the plane surface 2n is arranged in correspondence with the intersomatic space just before the introduction of the extremity of the part 2 ^bιs into the intersomatic space. At this time, the cage body 3 is inclined by about 45 ° with respect to the vertebral plates and the surfaces 10, 10 'are in contact therewith. When pressure is exerted at the rear of the body 3, it rotates through the profiles of the surfaces 10, 10 'until it is found in the horizontal plane of the cage.

According to a first variant embodiment, FIG. 9c illustrates a cage similar to that shown in FIGS. 9a and 9b but whose part 2 ^bιs is extended along a longitudinal axis eccentric to the median longitudinal axis of the body 3 so that the surface 2n stretches along a vertical axis. FIG. 9c shows in marked lines the final position of the cage, and in filigree its position of engagement of the cage 3. The insertion of the end of the part 2 ^bιs into the intersomatic space will here cause a movement of autorotation on the order of 90 °.

According to a second variant embodiment, FIG. 9d shows a cage whose part 2 ^bιs is extended in a longitudinal axis eccentric from the median longitudinal axis of the body, so that the surface 2n stretches along an inclined axis an angle β corresponding to 45 °. The insertion of the end of the part 2 ^bιs here will cause an autorotation movement of the order of 45 °, but with a cam effect more pronounced on one side of the body 3 than on the other.

Moreover, it goes without ^saying that part 2 can be located not on the anterior side but on one of the lateral sides of the cage body for transdermal or lateral approaches.

Figures 10a to 10c show an intervertebral cage according to a io ^th embodiment of the invention. This cage combines certain characteristics the previous execution mode including the first execution mode. More specifically, the cage comprises on the one hand, an insertion tongue 2 of depth Dp requiring a voluntary rotation gesture of the surgeon, and secondly, an intermediate portion of depth Dp 'and arranged between the insertion tongue 2 and the anterior side of the cage body 3. This intermediate portion comprises two lateral surfaces 11, 11 'shaped so as to orient the tongue 2 in a position inclined with respect to the horizontal plane of the cage by an angle β (FIG. 11c). On the other hand, the upper and lower surfaces 10, 10 "(FIG. 11b) of said intermediate portion are inclined and curved so as to reproduce the beginning of a helical gradient slope.The advantage of this cage is to obtain a partial expansion of the intersomatic space by a small rotation in order to then push the cage and cause the self-rotating effect through the intermediate part with a pressure much lower than the pressure that should be applied to a cage similar to 9a This combination also has the advantage, compared to a cage as described in the first embodiment, because of the presence of a tendril component, to be content with a weak angle of rotation, which reduces the shear stress forces between the two adjacent vertebrae: when these forces are too strong, they are likely to "skid" the cage at the time of the final push, and thus bring it out of the desired path. Finally, the height of the insertion tongue 2 may be less than the height H of the cage body 3, which may be an advantage for dodging hard or soft tissue at the time of insertion through the spinal canal.

To introduce this cage, the insertion tongue 2 is oriented in correspondence with the intersomatic space, and is inserted between the vertebral plates. A rotation substantially less than 90 ° is printed by the surgeon to partially expand the intersomatic space, and before this space is as high as the height of the body 3, the cage is pushed forward, and the intermediate portion takes over and continues the dilation of the insensomatic space according to the self-rotating principle, without no further voluntary rotation is required by the surgeon. In a variant (not shown), the part intended to expand the intersomatic space is located on one of the lateral sides of a side asymmetric cage body for trans-foraminal or lateral approaches.

Another variant (not shown) consists in combining the characteristics of the front part of a helical gradient pitch cage of the ninth embodiment, with, for example, the lateral fins of the eighth embodiment. This hybrid cage operates in an inverse manner to the hybrid cage of the ^10th embodiment, in that the cage is first inserted by pushing or impacting into the intersomatic space by its portion in helical gradient slopes, which initiates a self-rotational movement and slightly expands the intervertebral space, then, once the fins are engaged in intersomatic space to a sufficient depth, the surgeon exerts a voluntary rotation to complete the dilation of a sufficient height to penetrate the body of the cage in its entirety, by simple push. An alternative embodiment consists in replacing the anterior portion with helical gradient slopes by an anterior face of the body having a rounded or ogival profile, favoring the initial thrust or impact.

According to a 11 ^th embodiment as illustrated in Figure 11a, the expansion of the disc space between two vertebrae is performed by two rods 13, 13 'forming part of an ancillary installation of the cage. The advantage of this embodiment with respect to the third embodiment is to eliminate the bulk formed by the rods in the intersomatic space. Two longitudinal rails 15, 15 'intended to receive the rods 13, 13' pass right through the cage body 3. More precisely, these slides 15, 15 'are arranged along two distinct longitudinal axes perpendicular to the side front 7 of said body 3 and located relative to each other in two opposite corners of said side 7 along a diagonal. The rods can also be oriented in an axis not parallel to one of the lateral sides from the body. In order to ensure the stability of these rods 13, 13 ', they can be fixed to the body 3 temporarily, for example at the height of the rear part of said body 3, or by a fixing (by screwing or other means of fastening) to the ancillary laying (not shown) of the cage. The rods 13, 13 'can already be in position, as shown in Figure 11a, or can be slid after the introduction of the cage and its passage in the spinal canal. The rods 13, 13 'can be removed after the rotation of the cage body 3 and before its thrust into the intersomatic space, or after said thrust, when the cage is in its final position. Figure 11b shows a variant where only one of the rods 13, 13 'is removable, the other being an integral part of the cage body 3. This variant can be advantageous for reducing the space requirement of the intersomatic space to only one single rod, while providing stability to the lever arm formed by the two rods 13, 13 '.

FIG. 11c introduces a second variant in which the cage comprises a cage body 3 and a part 11 arranged on the front side of the body 3. This part 11 has an upper surface 10 and a lower surface (not visible) which are inclined so as to reproduce the beginning of a helical gradient slope. This cage makes it possible to obtain an effect comparable to that obtained by the cage according to the ^10th embodiment when it is introduced into the intersomatic space, namely a partial dilation of this space by a small rotation of the ancillary installation (not shown) in order to then push the cage and cause the self-rotating effect through the profile of the upper and lower surfaces of the portion 11. This cage here incorporates two movable rods 13, 13 'arranged in a horizontal plane parallel to a median plane of the cage body 3. One of the rods (13) is arranged in a longitudinal slideway 15 so that its end protrudes in the extension of the portion 11 which has a truncated end 2 while the Another rod 13 'is arranged in a slide or a longitudinal groove 16. After the rods 13, 13' are introduced into the intervertebral space, a rotational movement is printed on the anchoring device so as to lift 13. This movement may be modest (less than 45 °) because it must simply allow the engagement of the truncated end 2 of the portion 11 in the semi-expanded intervertebral space (the body 3 is also in the same plane as the two rods 13, 13 ', less than 45 °), before a thrust or impact on the posterior part of the body 3 causes the additional rotation necessary for the expansion of the intersomatic space, of a height sufficient for the insertion of the body into said intervertebral space. The advantage of this variant is that because of the low angle of rotation required for the lever effect, this reduces the cam effect induced by the rotation, which may be favorable in the presence of nerves or hard tissues nearby. It is obvious that the profile of the part 11, and mainly the upper surface 10 and lower (not visible) can vary, so as to ensure the most ergonomic connection to the upper and / or lower face of the body 3. Of course , the insert tongue portion 2 of depth Dp, can not only be in an oblique plane with respect to the horizontal plane in the horizontal plane of the cage, at any angle, but can also be in a horizontal plane, namely merged or parallel with the upper or lower surfaces of the body of the cage.

According to an I2 ^eme embodiment, Figure 12 shows a conventional cage consisting only of a body 3. This body 3 has on each of its lateral sides a groove 16, 16 'oriented in the direction of the longitudinal axis of the cage. These grooves 16, 16 'are intended to receive lamellae 21, 21' forming an integral part of an ancillary application, these lamellae having the function of expanding the intersomatic space between two vertebrae, according to the same principle as that described for the execution mode. To ensure the retention of the slats within the grooves, the latter preferably have a trapezoidal cross section. Of course, the slats may have a different section, in particular oval or oblong, if they can be held inside their grooves 16, 16 'by a mechanical means, for example at the level of the ancillary laying, or by a connecting member between the slats at their forward end projecting from the body 3. Note that the slats can be arranged not on the lateral sides of the body but on its upper and lower surfaces, even a configuration where one slat has its groove in the upper or lower surface of the body, and the other slat, its groove in one of the lateral sides. Moreover, one of the slats may have a width greater than the other.

An alternative embodiment (not shown) is to combine a removable blade feature of this ^I2th embodiment with a fin characteristic of the ninth embodiment.

According to Figure 13a, the slats 21, 21 'are mounted on the body 3 at the time of introduction of the cage. The anchoring device comprises in particular a part 22, for example of rectangular shape, adapted to be embedded in, or otherwise secured to, the rear part of the body 3. This part 22 encloses the slats 21, 21 'and helps to maintain them in the grooves 16, 16 '. It also contributes to transmitting the rotational force applied to the handle 221 of the ancillary. The cage body 3 has on its rear side a screw thread 223 in order to be able to screw an instrument 222. This instrument 222 slides inside the workpiece 22 and allows the body 3 to be pushed after the rotation of the latter. this has been done. In an alternative embodiment (not shown), the body 3 is not pushed individually, but it is the slats 21, 21 'which are removed once the body 3 is in its desired position. Of course, any other installation system associating lamellae 21, 21 'to a body 3 may be used for expansion and insertion of the body 3.

The strips 21, 21 'can also be positioned in an intermediate position (FIG. 12b), or even at the periphery of the rear face of the body 3, particularly if it is desired to reduce the width of the cage at the time of its passage through the spinal canal. The depth of the grooves 16, 16 'is not necessarily constant and may decrease from the rear to the front of the body 3 (Figure 12b). Similarly, the slats 21, 21 'may not be aligned in two parallel axes (Figure 12b), and / or have a non-constant width, either increasing or decreasing.

Figures 12c and 12d show a cage variant having an arched body to better fit the vertebral body contour, whether for a posterior or transforaminal or lateral approach. Once the cage body 3 is close to its final position, the blade 21 on the concave side of the body 3 is removed and a pressure is applied to said body 3 by the instrument 222 in an oblique axis with respect to the longitudinal axis in order to be able to rotate it on an axial or sagittal plane (assuming that the lamellae are in the distraction position of the intersomatic space).

FIG. 13 represents a ^third embodiment that combines the characteristics of the insertion flaps of the ninth embodiment with the retractable slats of the ^twelfth embodiment, namely, where the cage body 3 comprises on each of these lateral sides an arcuate longitudinal groove 16, 16 'in which are introduced blades 21, 21' arched which form an integral part of an ancillary laying. The variants are multiple, because the slats can also be straight or in a different plane of the plane of the flaps, and the slats can also be combined with an insertion tab of the fifth embodiment.

According to I4 ^th embodiment (Figure 14), a first and a second removable flap 22, 22 'is fixed at the end respectively of a first and second rods 23, 23' arranged in a first and second grooves 16, 16 ', said grooves being located along both side sides, respectively in the upper and lower part of the body 3. The flaps 22, 22' may be already in place at the time of introduction of the cage, or can be slid into the grooves 16, 16 'after the introduction of the body 3 to perform the rotation. The advantage of this cage is to be able to remove these flaps 22, 22 'after the exercise of rotation of the cage. The profile of the cross section of each groove 15, 15 'prevents the rotation of the flaps 22, 22' around their rod 23, 23 ' at the moment when the vertebrae exert a force "F" and "F1" against said flaps.

An alternative embodiment illustrated in Figures 14a, 14b and 14c is to introduce the flaps 22, 22 'in ducts 24, 24' through the body in the longitudinal direction and having a cross section corresponding to that of the flaps. Two rotational enclosures 25, 25 'arranged on the anterior side 7 of the body allow the flaps 22, 22' to achieve an arc of a circle up to the stop 23 (Figure 14c) in order to be able to deploy in their projecting position. situate to fulfill their function of lever arm. The cage is introduced with or without flaps through the spinal canal. In contact with the anterior side 7 of the body with the vertebrae, the flaps 22, 22 'are pushed by their respective rods 23, 23' inside the ducts 24, 24 'until they emerge in their rotating enclosures 25, 25 'respective. If the shutters were already in their ducts at the time of the introduction of the cage, they must simply be deployed. The deployment takes place by a rotation of the order of 190 ° rods which causes the rotation of the flaps 22, 22 'to the stop 23. The flaps are then introduced into the intersomatic space, and the rotation of the body is made for dilation purposes. The stop resists the force "F" exerted by the vertebra. To further stabilize the lever arm, the rods can be fixed directly to the body 3, for example in its rear part, or on the contrary only to the insertion device of the body. Alternatively, the flaps can be immediately deployed at the time of introduction of the body through the spinal canal, and after the rotation of the body, the flaps are folded into their input position as shown in Figures 14a and 14b, then removed from the body along their duct. If the surface of the vertebra prevents such reverse rotation of the flaps, the flaps can be advanced to protrude from the end of the stop 23 and complete the rotation turn and be removed from the body. Such a device can also combine a movable flap and a fixed flap, or a movable flap and a rod. An alternative embodiment consists in lining the body with deployable and then semi-retractable flaps, ie. that they are not removed with the laying device after introduction of the body, but are retracted inside the body to limit the size of the intersomatic space.

It goes without saying that certain features of any embodiment may be substituted and / or added to certain features of one of the other embodiments. In particular, each of the features attached to the body of the cage, insertion tongue, flaps, insertion rods, fins, may be in a resorbable material intended to disappear to give way to bone growth, or osteoconductive material , responsible for promoting said bone growth.

All variants are also likely to apply to cages that are not intended to be introduced by a posterior approach, including cages for trans-foraminal or lateral approaches.

Moreover, the end of the portion intended to expand the intervertebral space has in some embodiments a bevelled profile. In addition, all sharp edges of the body can be dulled. Convex or concave surfaces can also be made on the side of the body 3 or is the part intended to expand the intersomatic space in order to facilitate the transition between this part and said body 3.

Finally, the subject of the present invention also relates to two methods of insertion of the cage into the intersomatic space. More particularly, the invention relates to a first method of inserting a cage as described in some of the preceding embodiments, said method comprising the following steps:

the cage is introduced into the spinal canal with its insertion tongue 2 vertically until the front of the insertion tongue 2 is in contact with the vertebrae; - The cage is then turned a quarter of a turn or an angle substantially less than 90 ° to tilt the insertion tab 2 to the horizontal which allows its introduction into the intervertebral space slightly dilated;

- The cage is then turned a quarter of a turn or an angle substantially less than 90 °, but in the opposite direction of the second step, which has the effect of expanding the intervertebral space a height close to the height H ¹ of the insertion tongue 2 of the cage;

This is then pushed, or, if necessary, impacted, inside the intervertebral space, to its final position.

The invention also relates to a second method of inserting a cage as described in other modes of the preceding embodiments, said method comprising the following steps:

the cage is introduced into the spinal canal until the front of said cage is in contact with the vertebrae;

a pressure and / or impact and is exerted on the cage causing an autorotation movement thereof allowing the expansion of the intersomatic space; - An additional pressure is then exerted on the cage to introduce it into the intersdomatic space to its final position.

Claims

An intersomatic cage comprising a body (3) and a portion (2) for expanding the intersomatic space between two vertebrae (8, 8 ') by rotating the cage in order to introduce said cage (1), characterized in that the prism-shaped body (3) having a substantially planar upper surface (6) adapted to abut against the upper vertebra plate (8) and a substantially planar lower surface (6 ¹ ) adapted to press against the lower vertebrae plate (8 ¹ ).

2. Intersomatic cage according to claim 1, characterized in that the body (3) is a hexahedron whose upper and lower surfaces (6,

6 ') are inclined relative to each other by an angle between 2 ° and

20 ° from the anterior side (7) to its posterior side to allow adequate lordosis of the vertebrae (8, 8 ').

3. intersomatic cage according to claim 1 or 2, characterized in that the portion (2) for expanding the intersomatic space is arranged in a plane inclined at an angle β relative to the horizontal plane of the cage.

4. Intersomatic cage according to claim 3, characterized in that the angle β is between 40 ° and 60 °

5. intersomatic cage according to claim 1, 2, 3 or 4, characterized in that the portion (2) for expanding the intersomatic space is arranged on the front side (7) of the body (3) of the cage.

Intersomatic cage according to claim 1, 2, 3 or 4, characterized in that the portion (2) for expanding the intersomatic space is arranged on one of the lateral sides (3, 3 ') of the body (3). ) for unilateral, transforaminal or lateral approaches.

Intersomatic cage according to claim 5 or 6, characterized in that the portion (2) has a substantially oblong cross-section of height H ¹ and width W, the portion (2) being oriented so as to extend the front side (7) or one of the lateral sides (3 ', 3 ") of the cage body (3) in a plane inclined with respect to the horizontal plane of the cage.

Intersomatic cage according to claim 5, characterized in that the lateral flanks of the substantially oblong cross-section portion (2) extend beyond the edges of the front side (7) or one of the lateral sides (3). ', 3 ") of the cage body (3) so as to be able to expand the intersomatic space by rotation of the cage so that the height of this space is substantially greater than the height of the body (3).

9. Intersomatic cage according to any one of the preceding claims, characterized in that the body (3) of said cage (1) comprises a fin (9, 9 ') arranged along each of the two lateral sides (3 \ 3 ") of the cage body (3).

Intersomatic cage according to one of claims 1 to 7, characterized in that the part (2, 2 ^bιs ) comprises an upper and lower face (10, 10 ') and two lateral faces (11, 11'), said faces (10, 10 ', 11, 11') converging from the respective edges of the front side (7) or one of the lateral sides (3 ', 3 ") of the body (3) to a face (2n ), the upper and lower face (10, 10 ') of the portion (2) having an inclined surface and curved so as to reproduce the beginning of a helical gradient slope.

11. Intersomatic cage according to claim 9, characterized in that the face (2n) lies in a plane substantially parallel to the anterior side (7) or of one of the lateral sides (3 \ 3 ") of cage body ( 3).

Intersomatic cage according to claim 10 or 11, characterized in that the face (2n) is centered at mid-height and half-width of the anterior side (7) or of one of the lateral sides (3 \ 3 ") of cage body (3).

Intersomatic cage according to claim 10 or 11, characterized in that the face (2n) is situated close to one of the lateral flanks of the anterior side (7) and at mid-height of said side (7) of the cage body. (3).

Intersomatic cage according to claim 10 or 11, characterized in that the face (2n) is located near one of the corners of the anterior side (7) of the cage body (3).

15. Intersomatic cage according to claim 10, characterized in that the two lateral faces (11, 11 ') are profiled so that a portion of the portion (2) has a cross-sectional shape. substantially oblong Hp height and width Wp, and secondly, that this portion extends in the direction of its height Hp in a plane inclined by an angle β relative to the horizontal plane of the cage.

16. Intersomatic cage according to claim 14, characterized in that the height Hp is constant over a depth Dp.

17. Intersomatic cage (1) according to one of claims 1 to 5, characterized in that the portion (2) for expanding the intersomatic space comprises at least two rods (13, 13 ').

18. Intersomatic cage (1) according to claim 16, characterized in that the rods (13, 13 ") are arranged on the anterior side (7) of the cage body (3) in two opposite corners along a diagonal, said rods ( 13, 13 ') being oriented along an axis perpendicular to said side (7).

19. Intersomatic cage (1) according to claim 16 and 17, characterized in that at least one of the rods (13, 13 ') is removable and is an integral part of an ancillary laying.