WO2010046766A1

WO2010046766A1 - Articulated intervertebral stabilisation system

Info

Publication number: WO2010046766A1
Application number: PCT/IB2009/007205
Authority: WO
Inventors: Michael Perisic
Original assignee: Medtech Research Sa
Priority date: 2008-10-22
Filing date: 2009-10-22
Publication date: 2010-04-29

Abstract

The invention relates to an extra-discal system for connecting a first vertebra to a second vertebra. The system comprises a first element (1) for rigidly connecting to the first vertebra, a second element for rigidly connecting to the second vertebra, a connector (2) arranged so as to be rigidly connected to the first rigid connection element (1), and an intervertebral connection member (3, 3', 3") arranged so as to be connected or built into the connector (2) and the second rigid connection element. The system further comprises means (4, 4', 5, 5', 7, 7', 8, 8") for articulating the connection member (3, 3', 3") and the connector (2), or the first rigid connection element (1) and the connector (2), or the first rigid connection element (1), the connector (2) and the connection member (3, 3', 3"). Said articulation means (4, 4", 5, 5', 7, 7', 8, 8') are arranged so as to enable a displacement movement among the articulated parts when the system is assembled.

Description

ARTICULATED INTERVERTEBRAL STABILIZATION SYSTEM

The present invention relates to an articulated extradiscal intervertebral stabilization system.

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 treatments of these pathologies in their advanced stages make use of various systems of stabilization by extra-disc implants, in particular by the use of vertebral screws implanted in adjacent vertebrae and connected to each other by connecting members, of the plate or stem type. fixedly secured to the vertebral screws. These implants are applied in the anterior part of the column, or in its posterior part on both sides of the spine, or on the sides of the vertebral bodies.

These rigid implant systems have significantly improved the treatment of pathologies of the column, creating a distracting effect between the vertebrae of the segment particularly affected by the collapse of the disk or the degeneration of the facets, with as a result result decompression of nerve roots, and the acceleration of bone fusion of vertebrae adjacent to each other.

Unfortunately, these rigid systems, by locking the implant in the position of the instrumented segment at the time of the surgery, cause a destabilization of the column at the level of the instrumented segment, which progressively leads to a degeneration of the disks and facets of the segments adjacent to the segment. instrumented. In addition, rigid system instrumentation does not always exclude, or sometimes only marginally reduce, the pain experienced by treated patients. Finally, other negative effects of rigid systems are reported, such as the dislocation of the screws, for example in the presence of bone insufficiently dense, or the rupture of rods or screw caps, imposing in these cases complicated revision surgeries.

Another disadvantage of rigid constructions is that the screws implanted in adjacent vertebrae are not in an alignment plane, especially in case of instrumentation of more than one segment, and their axis of implantation in the vertebrae n '. is not necessarily the same from one vertebra to another. This last disadvantage is partly solved by the implantation of poly-axial screws, but the iatrogenic effects of the rigid constructions are not solved so far.

The object of the present invention is to provide a system that overcomes these disadvantages thus promoting the quality and speed of intervertebral fusion and reducing iatrogenic pain.

According to the invention, this object is achieved through an extra-disc system for connecting a first vertebra to a second vertebra. The system comprises a first securing element to the first vertebra, a second securing element to the second vertebra, a connector arranged to be secured to the first securing element, an intervertebral connecting member arranged to be connected or integrated with the connector and the second element of solidarity. The system further comprises means for articulation between the connecting member and the connector, or between the first securing element and the connector, or between the first securing element, the connector and the connecting member. These articulation means are arranged to allow a movement movement between the articulated parts when the system is assembled.

This results in a dynamic stabilization system, which, depending on the degrees and axes of mobility defined by the practitioner, is likely to accelerate and improve intervertebral arthrodesis, or conversely to maintain a sustainable mobility by supporting the weakened intervertebral segment by a clinical condition. The invention involves two distinct elements (for example a screw and a plate, or a screw and a connector, or a connector and a rod) fixed together, but relatively movable relative to each other. One of these two elements is preferably of cylindrical shape (screw body or rod) and the second element may be cylindrical (connector) or annular, but must have a diameter greater than the first element, so that it can be threaded around said first element. element. Either or both of the two elements may also be non-cylindrical in some of the embodiments of the invention. The mobility between the two elements is ensured by the association of at least one convex surface or a protruding part (male element) arranged on one of the elements, with a concave surface or a cavity (female element) arranged on the other elements. These additional features are configured so that the two respective elements that integrate them can pivot or tilt relative to each other in a multitude of axes around the longitudinal axis of the element called "cylindrical""(Rod or screw), according to the variants of the invention.

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

Figure 1 shows a vertebral screw, a connector and an intervertebral rod of the articulated extra-discal system according to the invention;

Figure 1a shows a cross section of the vertebral screw of Figure 1 at the connector; Figure 1b shows a segment of the vertebral screw having a portion of the hinge means;

Figures 2a and 2b show the spinal screw and the connector in a first and second position;

3 shows a vertebral screw, a connector and an intervertebral rod of the articulated extra-discal system according to a first variant of the invention; Figure 4 shows a vertebral screw and a connector of the extra-discal system articulated according to a second variant;

Figure 5 shows a vertebral screw, a connector and an intervertebral rod of the extra-disc system articulated according to a third variant; Figure 6 shows a vertebral screw, two connectors and two intervertebral rods of the extra-discal system articulated according to a fourth variant;

Figure 7a shows a cross section of a vertebral screw and a connector of the extra-discal articulated system according to a fifth variant;

Figure 7b shows a view similar to Figure 7a after rotating a quarter turn of the connector;

Figure 8a shows a connector and an intervertebral rod or a vertebral screw of the articulated extra-discal system before assembly according to a sixth variant;

Figure 8b shows a view similar to Figure 8a after assembly; Figure 8c shows the connector and the intervertebral rod or the vertebral screw of the extra-disc system hinged after assembly with a change in the joint;

Figures 9a, 9b and 9c show schematic views of an articulation of the extra-disc system articulated respectively in three different positions;

Figure 10 shows a cross-section of a vertebral screw or an intervertebral stem and a connector of the articulated extra-discal system having a hinge as defined by Figures 9a, 9b and 9c according to a seventh variant; Figure 11a shows a vertebral screw or an intervertebral stem, a connector and an intervertebral rod of the extra-discal system articulated with a cross section at the screw and the connector according to an eighth variant when the articulated assembly is in a first position ;

Figure 11b shows a view similar to Figure 11a when the articulated assembly is in a second position;

Figure 12 shows a cross section of a vertebral screw and a connector of the extra-disc system articulated according to a ninth variant; Figure 13 shows a cross section of a spinal intervertebral screw or a rod and connector system of the extra-discal articulated according to a ^10th embodiment;

Figure 14 shows a cross section of a spinal intervertebral screw or a rod and connector system of the extra-discal articulated according to a ^11th embodiment;

Figure 15 shows a spinal screw, a connector and an intervertebral rod of the extra-discal system articulated with a cross section at the screw and the connector according to a I2 ^th variant; Figure 16 shows a spinal screw, a connector and an intervertebral rod of the extra-discal system articulated with a cross section at the screw and the connector according to a I3 ^th variant; Figure 17 shows a connector provided with a hook on an intervertebral stem according to a ^14th variant; Figure 18a shows a cross-section of a screw with a notch and a connector with a ring segment according to a ^fifth variant;

Figure 18b shows the screw with the notch and the ring segment connector in the tilted position;

Figure 18c shows the screw and connector of Figure 14a with ring segment in reverse tilted position

Figure 19 shows a spinal screw, a connector and a stem according to a 16 ^th variant;

Figure 20 shows a vertebral screw, a connector and a rod intervertebral extra-discal articulated system with a cross-section at the screw and the connector according to a 17 ^th embodiment;

Figure 21a shows a cross section of a circular base cone in an oval base conical cavity;

Figure 21b shows a cross-section of an oval base cone in an oval base conical cavity; Figure 21c symbolizes a cross-section of a pyramidal cone in a pyramidal cavity;

Figure 21 d symbolizes a longitudinal section of a cone whose longitudinal axis is offset from that of the conical cavity; Figure 22a shows a longitudinal section of a vertebral screw and a connector of the extra-discal system hinged in an ^eighth variant before securing the connector to the screw;

Figure 22b shows a view similar to Figure 22a, after the fastening of the connector to the screw.

Figure 23 shows a cross section of a vertebral screw and a connector of the extra-disc system articulated according to a variant ^igeme ;

Figure 24 shows a connector and a vertebral screw the articulated extra-disc system or the screw consists of two parts separable in a 20 ^th embodiment;

Figure 25 shows a vertebral screw and an intervertebral plate of the extra-discal system articulated according to a 21 ^th variant;

Figure 26 shows two vertebral screws and an intervertebral plate of the extra-disc system articulated according to a 22 ^th variant; Figure 27 shows a spinal screw, a double connector and two intervertebral rods of the extra-discal system articulated according to a 23 ^th variant;

Figure 28 shows a vertebral screw, a double connector and two vertebral rods of extra-discal articulated system according to a ^24th embodiment;

Figure 29 shows a vertebral screw, a rod and a vertebral plate of the extra-disc system articulated along a 25 ^th embodiment;

Figure 30 shows a vertebral screw hinged with a sliding connector along a shaft prosthesis according a 26 ^th embodiment;

Figure 31 shows an articulated sacral support with a rod eye cup according to a ^27th embodiment;

The extra-disc system according to the invention comprises, in particular, according to FIG. 1, a vertebral screw 1, and a connector 2 connecting said screw to an intervertebral rod 3. The connector 2 comprises a first part arranged to be adjusted around the circumference of the body of the vertebral screw 1 and a second portion arranged to fit around the circumference of a segment of the rod 3. The vertebral screw 1 comprises two notches 4, 4 'which are diametrically opposed by relative to the axis of the screw. The connector 2 comprises a circular ring 5, which is arranged on the inner circumference of the connector 2 around the screw 1 and between the two notches 4, 4 'as shown in Figure 1a which shows a cross section of the screw 1 and the connector 2 at the notches 4, 4'. Figure 1b shows a segment of the screw 1, and shows that the notch 4 has a concave portion 4a whose radius of curvature is marginally greater than the convex radius of curvature of the cross section of the ring 5 to allow movement 5. The two protruding triangles 4b, 4b 'are arranged on either side of the concave portion 4a, the apex of each triangle 4b, 4b being oriented so as to face the concave portion. 4a. The ring 5, symbolized in Figure 1b by two arcs in two different positions, has freedom of movement to the lateral sides of the triangles. The degrees of flaring of the lateral sides of the triangles 4b, 4b 'as well as the space existing between the periphery of the ring 5 and the periphery of the screw body, determine the degree of freedom of pivoting of the ring 5 and therefore of the connector 2. Thus, assuming a rear stabilization system, a relatively free articulation in the horizontal plane and relatively rigid in the vertical plane, can serve as a stay to limit bending, and distractor element to limit extension, but will allow certain degrees of freedom in rotation, which is favorable for intervertebral fusion. Figures 2a and 2b show the same screw 1 with the connector 2 being in two extreme positions. It should be noted that the notches 4, 4 'comprising the concave part can be arranged on the connector 2 while the ring 5 is arranged on the screw 1, with a similar result. Furthermore, the concave portion of each notch 4, 4 'can be reduced, which would affect the degrees of pivoting which are mainly determined by the clearance space between the two elements. Finally, the connector 2 can be reduced in its connective part with the screw 1, to a simple ring, attached by a second ring or by any other method of attachment to the rod 3.

According to a first variant of the invention illustrated in FIG. 3, the extradiscal system comprises a hinge functioning according to the same principle, but between an intervertebral rod 3 and a connector 2. In this case the notches 4, 4 'are arranged on the intervertebral stem 3 in a diametrically opposed manner by relative to the longitudinal axis of the rod 3 and the ring 5 is arranged on the inner circumference of the connector 2. Note that the rod 3 can connect more than two vertebrae together, or by more than two connectors, either by being secured directly with several vertebral screws, or by a combination of both. Note also that the connector may also have a hinge (not shown in the figure) at its point of attachment with the screw 1.

According to a second variant of the invention illustrated in FIG. 4, the extra-disc system comprises, instead of a ring, two half-spheres 5, 5 'which are arranged on the body of the screws in diametrically opposite ways. relative to the axis of the screw. The connector 2 comprises a groove 4 whose cross section forms a circular arc of diameter greater than that of the half-spheres 5, 5 '. The connector 2 can thus pivot about the axis consisting of the two half-spheres. This connector also has degrees of mobility, but limited in the axis perpendicular to its pivot axis, if the difference between the radius of curvature of the half-spheres 5, 5 'and the radius of curvature of the groove 4 is sufficient . The half-spheres 5, 5 'do not necessarily have to represent half of a sphere, and can be of a fraction higher or lower than this half. Similarly, the groove 4 may be of varying depths (but should be shallower than the height of the half-spheres), and may have a profile that is not of a constant diameter.

According to a third variant of the invention as illustrated in FIG. 5, the convex and concave characteristics are reversed. In other words, the half-spheres 5, 5 'are arranged on the connector 2 and are intended to be introduced at least partially into the groove 4 which is arranged on the periphery of the screw body 1, said connector 2 being also attached to an intervertebral stem 3.

According to a fourth variant of the invention as illustrated by FIG. 6, the extra-disc system comprises two grooves which are arranged around the periphery of the screw body 1 in a parallel manner, where the first groove (non-visible) of the screw 1 serves to connect the latter to a first connector 2a by two half-spheres (non-visible) included in said connector 2a. The latter has a recessed cylindrical portion for receiving the end of a first intervertebral rod 3a. The second groove 4 of the screw 1 serves to connect the latter to a second connector 2b by two half-spheres 5a, 5b integrated into the latter, this second connector 2b being itself connected to a second intervertebral rod 3b, this last connection can be rigid or articulated. The particularity of the first rod 3a resides in the fact that it comprises two parallel grooves 4c, 4d over almost its entire circumference. The first connector 2a integrates, meanwhile, two half-spheres 5c, 5d arranged diametrically opposite on the inner surface of the cylindrical portion of the connector 2a, the two half-spheres 5c, 5d being intended to be inserted into the one or other of the grooves 4c, 4d of the rod 3a according to the length desired by the practitioner between the vertebral screw 1 and a vertebral screw of the adjacent vertebra. For this purpose, the grooves 4c, 4d are segmented in two, in order to allow the passage of the half-spheres 5c, 5d, and after a slight rotation of the rod 3a, the assembly of the half-spheres 5c, 5d in the 4c or 4d groove at the desired end location. The rod 3a could also have more than two parallel grooves and one variant would consist in arranging these grooves 4c, 4d to the connector 2a and the half-spheres 5c, 5d to the rod 3a.

Another particularity of the invention shown in FIG. 6 is the presence of two "duct" grooves 4e, 4f on the screw 1, in order to allow the second connector 2b to be threaded onto the screw, by making the two halves follow. -spheres 5a, 5b the outline devitious driving grooves until they reach the groove 4. These driving grooves 4e, 4f can have a trajectory in "chicane", to avoid the dislocation of the half-spheres 5a, 5b out of the groove 4.

According to a fifth variant of the invention, as illustrated by FIGS. 7a and 7b, the extra-disc system comprises a screw 1 or a rod 3 and a connector 2, integrating a ring 5 which is segmented so that two notches 4, 4 'integrated in the screw 1 or the rod 3 can be guided through a passage when the connector 2 is arranged around the screw or the rod (Figure 7a) before that a quarter-turn rotation of the connector 2 is performed to secure the assembly (Figure 7b).

According to a sixth variant of the invention as illustrated by 8a, 8b and 8c, the articulation means of the extra-discal system comprises two concave portions 4 (only one is visible), arranged diametrically opposite on the surface. internal portion of the cylindrical portion of the connector 2 and two convex portions 5 (only one is visible), arranged diametrically opposite on the screw body 1 or on the intervertebral rod 3 with respect to their longitudinal axis, the two convex portions 5 being positioned in the two concave portions 4, when the assembly is assembled. The two concave portions 4 have a spherical cell shape while the two convex portions 5 are in the shape of a half-sphere. The radius of curvature of the cells 4 is substantially greater than the radius of curvature of the two half-spheres 5 so as to allow rotational movements of these half-spheres in the cells, essentially pivoting about the axis constituted by the half-spheres. spheres. The connector 2 is threaded around the rod 3 or around the screw body 1 at the segment where there is a groove 6 (Figure 8a). This groove 6 is arranged on the inner surface of the cylindrical portion of the connector 2 to guide the half-sphere 5 integrated with the rod 3 or the screw body 1 at its location in the cell 4 (Figure 8b). The walls of the groove 6, as shown in Figures 8a and 8b, flare to facilitate access of the half-sphere 5 in the cell 4 and to prevent dislocation out of the cell. FIG. 7c represents a variant where the cell 4 is eccentric with respect to the groove 6, in order to further limit the risk of dislocation of the half-sphere 5 out of the cell 4.

The two pairs of hemisphere / cell may be replaced by a different assembly, for example by two cone-shaped projections integrated in a first element (screw or connector) and intended to be introduced into two cavities of corresponding shape arranged on a second element (screw or connector). The two cones of the first element have a height greater than the depth of the cavities of the second element, but have a diameter at their base which is lower. The second element comprising the cavities therefore relies on the tip of the respective cones integrated in the first element and oscillate around the axis of these cones. Figures 9a, 9b and 9c are schematic views of such an assembly, wherein the conical cavity 7 of the second element is of a depth "P" less than the height "H" of the cone 8 of the first element. The diameter "D" of the cone of the first element is on the other hand smaller than the diameter "D" of the conical cavity 7 of the second element. Figure 9b illustrates a right lateral oscillation of the conical cavity 7 of the second element with respect to the stable cone of the first element, while Figure 9c illustrates a left posterolateral oscillation. The advantage of this variant is to offer, in addition to degrees of rotation about the axis constituted by the two pairs "cone / conical cavity", mobility in different axes, in particular perpendicular to the axis of said rotation .

According to a seventh variant of the invention as illustrated by FIG. 10, the articulation means of the extra-discal system rests on the assembly of a cone in a corresponding cavity. More particularly, FIG. 10 represents a cross-section of a vertebral screw 1 or of an intervertebral rod 3, comprising two conically shaped cavities 7, T which are diametrically opposite with respect to the axis of the screw or rod. , and a connector 2 having two cone-shaped protrusions 8, 8 'which are arranged to correspond with the two cavities 7, T after the assembly of the screw 1 or the rod 3 with the connector 2. The cavities conical 7, T have a depth marginally less than the radius of the cross section of the screw body 1 or the rod 3, and the center of gravity of the screw / rod is around the point of virtual junction between the conical cavities. The connector 2 can thus oscillate around the screw / rod according to a maximum arc defined by the differential

"D" between the slope of the cones 8, 8 'and that of the conical cavities 7, T.

According to an eighth variant of the invention, the extra-discal system may comprise an elastic means arranged to damp the movement of the connector 2 relative to the vertebral screw 1 (Figures 11a and 11b). The advantage is to offer a freedom of mobility of one element relative to the other in an additional plane, and to contain this movement by a damping effect. This can be useful in particular in a system for providing a distraction between two vertebrae, while providing relative mobility and damped extension and / or flexion. FIG. 11a shows such a system, where a first cone 8 is rigidly integrated with the connector 2 while a second cone 8 'is integral with a movable element 10 which slides inside the connector 2, this sliding being damped by an elastomeric synthetic substance 9. Figure 11b illustrates the same connector 2 in an extended position of the spine (assuming a posterior system), where the screw 1, describing a downward movement, causes the cone 8 'downwards, this sliding being damped by the synthetic substance. The cone 8 of the connector 2 is thus here no longer in contact with one of the conical cavities 7, 7 'of the screw 1. The damping substance 9 can be of any synthetic or natural nature, or can be substituted by a damping or elastic mechanical system, in particular by one or more springs. The same system can be applied to all forms and embodiments of the invention. Other variants (not shown) consist of systems with a cone or semi-sphere substantially non-rigid, or grooves, cells or conical cavities covered with a non-rigid coating.

12 shows a ninth variant of the invention, where there is a clearance space between the two cones 8, 8 'of the connector 2 and the respective conical cavities 7, T of the screw 1 without a buffer zone. The advantage of this variant, in the context of a rear stabilization system, is to create a stay restricting intervertebral mobility in flexion, while ensuring relative mobility in extension (in addition to degrees of freedom offered in rotation), this is likely to promote intervertebral fusion. FIG. 12 illustrates the position of the connector 2 with respect to the screw 1 in the bending position, where one of the conical cavities 7, T of the screw 1 bears on one of the cones 8, 8 'of the connector 2 , while there is a clear zone of movement between the other conical cavity T of the screw 1 and the other cone 8 'of the connector 2. The same variant can also be applied for a distraction effect, excluding extension and limiting flexion. Another advantage of this variant is to allow the integration of cones and conical cavities respectively lower and less deep, since the center of gravity of the screw 1 must no longer be at its center, but at the bottom of one of the conical cavities 7, 7 'on which rests one of the two cones 8, 8' of the connector 2 to at one time or another.

According to a ^third variant of the invention (FIG. 13), the connector 2 comprises an annular portion provided with a first and second conically shaped projection 8 'arranged diametrically opposite respectively in a first and a second cavity. conically shaped 7, T arranged on the screw body 1 or the rod 3. The particularity of this variant is that the ends of the cones 8, 8 'meet and are connected together at the longitudinal axis of the screw 1 or stem 3.

According to a 11 ^th embodiment of the invention (Figure 14), the connector 2 has identical characteristics to the io ^th except variant of a spherical member 20 arranged in a complementary recess 20 ', this element 20 being connected on both sides of the first and second projections 8, 8 '.

According to I2 ^th variant of the invention (Figure 15), an inner portion 10 which has a contour of substantially rectangular shape and comprises the features of the connector according to the n ^th variant is arranged in a rectangular housing within the connective part of the connector 2 and around the screw body 1. This part 10 is detached from the outer shell of the connector 2. Furthermore, a synthetic substance 9 of elastomer type is arranged between a first side of the inner part 10 and the outer shell of the connector 2 and between an opposite side of said portion 10 and said outer shell of the connector 2. Note that the shape of the contour of the inner portion 10 may be other than rectangular, in particular triangular. In this case, the inner contour of the outer shell of the connector 2 will have a complementary shape, in particular triangular.

I3 ^th variant of the invention (Figure 16) provides a system similar to the 12 ^th or variant but the inner portion 10 comprises only one projection 8 conically to the end of which a spherical element 20 is connected , this being arranged in a housing located in the longitudinal axis of the screw 1. According to I4 ^th variant of the invention as illustrated in Figure 17, the extra-disc system comprises a connector 2 provided with a hook 11, the connector being pivotally connected with the rod 3 by intervertebral two hemispheres 5, 5 'located on a cylindrical portion of the rod diametrically opposite in two cells 4, 4' corresponding. The hook 11 is adapted to be attached to a vertebra instead of a screw.

The articulation between a screw and a connector, or a connector and a rod, can also be done by two pairs of male / female characteristics which are, of course, diametrically opposite with respect to the axis of the screw or rod, but are not in a plane perpendicular to the longitudinal axis of the screw, rod or connector, but in an oblique plane. This in particular to restrict the axes of possible mobility, and pre-constrain the mobility of the joint in a limited number of axes.

Figures 18a, 18b and 18c illustrate a 15 ^th embodiment of the invention, or the joint between a screw 1 and a connector 2 is performed by a single concave portion 4 arranged on the screw body and a ring segment 5 integral with the connector 2 and arranged in correspondence with the concave portion 4. Figure 18a shows a cross section of the screw 1 and the connector 2, where the concave portion 4 surrounds an annular segment 5. According to Figures 18b and 18c, in addition of the "pivoting" mobility obtained with two notches and a ring, as illustrated by Figures 2a and 2b, we obtain here a mobility in two new directions along the longitudinal axis of the screw (symbolized by continuous line arrows), on both sides of the notch / ring segment pair. By combining the mobility axes of FIGS. 2a and 2b with these new axes, the degrees of freedom of movement of the connector 2 relative to the screw 1 are thus increased.

According to I6 ^th variant of the invention as illustrated by Figure 19, a single conical recess 7 is integrated with the screw 1 based on a single integrated cone 8 to the connector 2. In this embodiment, flexion position (for a posterior system), the conical cavity 7 rests on the cone 8, maintaining the freedom of rotational mobility. In extension, the edge of the screw 1 will rest on the inner wall of the connector 2 opposite the cone / conical cavity articulation. It is possible to arrange an upper deflection zone between these two walls, in order to accentuate the mobility in flexion / extension, as long as this space is less than that which would lead to a risk of dislocation of the cone 8 out of the conical cavity 7 The dislocation of the cone 8 is excluded due to the insufficient clearance space between the periphery of the screw body 1 and the internal face of the connector 2. This variant can be applied mutatis mutandis to a joint between a connector and a rod 3.

According to a 17 ^th embodiment of the invention as illustrated in Figure 20, a damping zone 9 is arranged opposite of the location of the pair cone / conical recess 7, 8. The system is shown here in the extended position (assuming a posterior system), that is to say where the screw 1 moves downwards, causing a movable portion 10 of the connector 2 downwards, this movement being damped by a damping substance 9 of the elastomer type. This movement creates a clearance space between the cone 8 and the conical cavity 7 which will be reduced or canceled by a next bending movement. A variant (not shown) consists in not integrating a moving component to the connector, and simply arranging the damping substance between the screw body and the connector.

The cone / conical cavity pair can have variable shapes, in particular to restrict or orient the degrees of mobility of the system. By way of example, Figures 21a, 21b and 21c show a cross section of a cone 8 arranged in a cavity 7 in different configurations. Figure 21a shows a cone 8 having a circular base while the cavity 7 has an oval base. According to Figure 21b, both the cone 8 and the cavity 7 have an oval base. As for FIG. 17c, it represents a transverse section of a pyramidal cone 8 arranged in a cavity 7 of complementary shape (negative pyramid), according to the principles already described for the cone / conical cavity pair in order to allow failover in only four planes, and to prohibit a rotation of the connector around the longitudinal axis of the pyramids. In addition, the Figure 21d shows a pair of cone / conical cavity 7, 8 whose tip, respectively the bottom, are eccentric from the perpendicular axis of the center of their respective base. A variant (not shown) consists in proposing that one or the other of the pyramids (positive or negative), or both, be of rectangular form (s), so as not to allow tilting only in two planes.

Whatever the system configurations described in the different figures, the male / female pairs can also be reversed between the screws / rod and the connector, that is to say that the characteristic of cone, half-sphere and ring can be on the screw / rod, and the characteristic conical cavity, cell or groove and notch, on the connector, and vice versa.

Figures 22a and 22b describe a mechanism for assembly of the connector 2 of the vertebral screw 1 or intervertebral rod 3 during surgery in a iβ ^th variant. The connector 2 comprises a chamber 14 in which the cone 8 is movably attached to a hinge. The connector 2 is threaded around the screw 1 with the cone 8 tilted inside the chamber 14. The internal walls of the chamber 14 contain, in any case on a part, a thread, so that a screw 15 can be screwed into the chamber 14 to tilt the cone 8 in the conical cavity 7 and maintain it in this final position. There are many variants of deployment and attachment of a cone, not described. The inner chamber can also be located in the screw 1 or the rod 3. A I9 ^th variant of the invention, shown in Figure 23 consists of using a connector 2 containing no cone but a threaded conduit 16 and a cone 8bis comprising a thread at its base, then, to thread the connector 2 around the screw 1, and, finally, to screw the cone 8bis from the outside into the threaded duct 16 of the connector 2, in its final position in the cavity conical 7. 20 ^th embodiment of the invention as shown in Figure 24, consists in screwing a first component 1a screw into the vertebra and then screwed into this first component a second component 1a 1b preassembled with a connector 2, by a pair of half-sphere 5 / cell 4. According to a 21 ^th variant, the connector 2 is an integral part of an intervertebral plate 3 'as illustrated in FIG. 25. This plate 3' has a circular orifice in which the body of a vertebral screw 1 is arranged. dimensions of the opening are determined so as to have a clearance space between the screw 1 and the edge of the orifice of the plate 3 '. A conical cavity 7 is arranged on the screw 1 while a cone-shaped projection 8 is located on the edge of the orifice to be introduced into said cavity to provide the connection between the intervertebral plate 3 'and the screw 1 while increasing the mobility of the system. This mobility is further increased by a flexible portion 17 integrated with the plate 3 'adjacent to the edge of the orifice which is opposite the projection 8. The plate 3' can of course be replaced by a rod comprising one its end has a similarly shaped eyelet at the end of the plate.

According to a 22 ^th embodiment of the invention (Figure 26), the extra-disc system includes a spinal plate 3 "connected to two vertebral screws 1a, 1b introduced into the same vertebral body as well as one or more vertebral screw ( unrepresented) introduced into a second vertebral body (not shown) The advantage of this variant is to constitute a stay so as to limit the movements in extension, while allowing slight rotational movements thanks to the two pairs of cones The lateral bending and bending movements are also possible to the extent permitted by the clearance space between the edge of the respective screws and the edge of the respective orifices of the plate.

The inter-disc system can integrate a combination of different articulation sets according to certain previously described variants. A 23 ^rd embodiment of the invention illustrated in Figure 27 is an example of one of the possible combinations. The connector 2 is configured to connect a vertebral screw 1 to one of the ends of two rods 3a, 3b, the other end being intended to be connected respectively to a first and second vertebra arranged on either side of the vertebra median on which the screw 1 is screwed. Note that the connector 2 is articulated with the screw 1 by a pair of cone / conical cavity 8, 7 while one of the rods 3a, 3b is assembled to the connector 2 by a first and second half-sphere 5a, 5b respectively arranged in a first and second cell 4a, 4b. FIG. 28 represents a 24 ^th variant where a single connector 2 is connected laterally to two rods 3a, 3b for one of them 3b by a single pair of hemisphere 5 / cell 4.

According to a 25 ^th embodiment of the invention (Figure 29), the extra-disc system comprises on the same vertebral screw 1, as a joint with a connector 2, itself attached to a stem 3, a second articulation with an intervertebral plate 3 ', without a second connector is necessary.

A 26 ^th embodiment of the invention (Figure 30), is to combine a screw assembly 1/2 at a connector pin 3 by adding an additional mobility property in sliding the connector 2 along the stem. The connector 2 is here not secured to the rod 3 but is free to slide along the latter to a stop 21 limiting flexion movements (for a posterior system). The connector 2 in contact with the rod has, in its median part, a marginally greater diameter than the rod 3, this diameter gradually increasing to the lateral sides of the connector 2. This allows the connector 2 to switch on the rod 3 on its middle part and slide along this rod. Note that the portion of the connector 2 enclosing the rod 3 could consist only of a ring. Another feature shown in Figure 30 is the presence of several conical cavities 7, T, 7 "of which only one will host a cone 8 arranged on the connector 2 to facilitate assembly of the system in situ.

Finally, according to a 27 ^th and last variant as illustrated in Figure 31, the invention can also be applied to a sacred socket 30, that is to say the instrumentation of the vertebral segment L5-S1. This sacral grip 30, screwed on the sacrum by two vertebral screws 1a, 1b and articulated by the interlocking of a cone 8 in a conical cavity 7 with a stem 3 having an eye-piece, connecting the sacral socket to the adjacent vertebra ( L5).

Claims

1. Extra-discal system for connecting a first vertebra to a second vertebra, the system comprising: a first securing element (1) to the first vertebra,

a second securing element to the second vertebra,

a connector (2) arranged to be secured to the first securing element (1),

an intervertebral connection member (3, 3 ¹ , 3 ") arranged to be connected to or integrated with the connector (2) and the second securing element, and

hinge means (4, 4 ', 5, 5', 7, 7 ', 8, 8')

between the connecting member (3, 3 ', 3 ") and the connector (2), or

between the first securing element (1) and the connector (2), or

between the first fastening element (1), the connector (2) and the connecting member (3, 3 ', 3 "), these articulation means (4, 4", 5, 5', 7 ", 7 ', 8, 8') being arranged to allow a movement movement between the articulated parts when the system is assembled.

2. Extra-disc system according to claim 1, wherein the first fastening element (1) is a vertebral screw screwed into the first vertebra.

3. Extra-disc system according to claim 1 or 2, wherein the connector (2) comprises a connective portion arranged to fit around at least half of the circumference of a portion of revolution, preferably cylindrical, of the securing element (1) and / or the connecting member (3).

4. Extra-disc system according to claim 1, 2 or 3, wherein the hinge means comprises at least a convex portion (5, 5 ') or a projection (8, 8') arranged on the first fastening element. (1) and / or on the connector (2) and / or on the connecting member (3), and a concave portion (4, 4 ') or a cavity (7, 7') arranged on the first solidarity element (1) and / or on the connector (2) and / or the connecting member (3) and in correspondence with the convex portion (s) (5, 5 ') or the projection (s) (s) (8, 8 ') articulation means, leaving a clearance space to allow movement between the articulated parts.

An extra-disc system according to claim 3, wherein an inner portion (10) arranged inside the connective portion of the connector (2) incorporates at least one convex portion (5, 5) or a projection (8, 8 ') intended to be arranged in correspondence with at least one concave part (4, 4 ") or a cavity (7, 7') situated on the first fastening element (1) and / or on the connecting member ( 3), said inner portion (10) being disengaged from the outer casing of the connector (2).

6. Extra-disc system according to claim 5, wherein the inner portion (10) surrounds the entire periphery of the revolution portion of the securing element (1) and / or the connecting member (3). ), and wherein the periphery of the inner portion (10) is next to the inner contour of the outer casing of the connector (2).

7. Extra-disc system according to claim 3 or 5, wherein the hinge means comprise a first and a second convex portion (5, 5 ') arranged on the connective part of the connector (2) or on the inner part ( 10) of the connector (2) diametrically opposite and in correspondence with respectively a first and a second concave portions (4, 4 ') arranged on the first fastening element (1) and / or on the connecting member (3). ).

8. Extra-disc system according to claim 3 or 5, wherein the hinge means comprise a first and a second concave portion (4, 4 ') arranged on the connective part of the connector (2) or on the inner part.

(10) of the connector (2) diametrically opposite and in correspondence with respectively a first and a second part convex (5, 5 ") arranged on the first securing element (1) and / or on the connecting member (3).

9. Extra-disc system according to claim 3, 5 or 6, wherein the hinge means comprises a projection (8) in the form of cone or truncated cone arranged on the connective part of the connector (2) or on the part internal (10) connector (2), in correspondence with a cavity (7) of conical shape and larger dimensions, said cavity (7) being arranged on the first securing means (1) and / or on the body of link (3).

10. Extra-disc system according to claim 4, 5, 6 or 9, wherein the projection (8) is integral at its end with a spherical element (20) arranged in a complementary shaped housing (20 ') located in the first securing element (1) and / or in the connecting member (3), the housing (20 ') being arranged to communicate with the cavity (7).

11. Extra-disc system according to claim 3, 5 or 6 wherein the hinge means comprise a first and a second projection (8, 8 ') in the form of cone or truncated cone arranged on the connective part of the connector ( 2) or on the inner part (10) of the connector (2) diametrically opposite and in correspondence with a first and a second cavity (7, 7 ') of conical shape and of larger dimensions, the first and the second cavity ( 7, 7 ') being arranged on the first securing element (1) and / or on the connecting member (3).

12. Extra-disc system according to claim 5, 6 or 11, wherein the end of the first and the second projection (8) are integral with a common spherical element (20) arranged in a housing of complementary shape located in the first securing element (1) and / or in the connecting member (3), the housing being arranged to communicate with the first and the second cavity (7, 7 ').

13. Extra-disc system according to claim 3 or 5 or 6, wherein the hinge means comprises at least one cavity (7) in the form of cone or truncated cone arranged on the connective part of the connector (2) or on the inner part (10) of the connector (2), in correspondence with a conical-shaped slit (8) of smaller dimensions, the said projection (8) being arranged on the first fastening element (1) and / or on the connecting member (3).

14. Extra-disc system according to claim 3, 5 or 6, wherein the hinge means comprise a first and a second cavity (7, 7 ') in the form of cone or truncated cone arranged on the connective part of the connector. (2) or on the inner portion (10) of the connector (2) diametrically opposed and in correspondence with a first and a second projection (8, 8 ') of conical shape and smaller dimensions, the first and the second projection (8, 8 ') being arranged on the first fastening element (1) and / or on the connecting member (3).

15. Extra-discal system according to any one of the preceding claims, further comprising at least one resilient means (9, 17) arranged to damp the movement of the connector (2) relative to the first fastening element (1) and / or with respect to the connecting member (3).

16. Extra-disc system according to any one of claims 4 to 14, wherein an elastic means is arranged around the or projections (8, 8 ') within the cavity or cavities (7, 7'). ).

17. Extra-disc system according to claim 5 or 6, comprising at least one elastic means (9) arranged between the inner portion (10) of the connective portion of the connector (2) and the outer casing thereof.

18. Extra-disc system according to any one of the preceding claims, wherein the connecting member is a plate (3 ¹ ) shaped substantially rectangular and wherein the connector (2) is integral with the plate (3 ¹ ).