WO2010060423A2

WO2010060423A2 - Intervertebral implant

Info

Publication number: WO2010060423A2
Application number: PCT/DE2009/001710
Authority: WO
Inventors: Henning Kloss
Original assignee: Privelop-Spine Ag
Priority date: 2008-11-30
Filing date: 2009-11-30
Publication date: 2010-06-03
Also published as: WO2010060423A3

Abstract

The invention relates to intervertebral disk implants which imitate the natural degrees of freedom of movement by allowing translational and/or rotational movements of the disk located between the vertebrae relative to the bottom plate independently of the possible movements of the cover plate relative to said disk located between the vertebrae. Said movements can be performed by mounting the disk located between the vertebrae on the bottom plate by means of fastening means disposed inside the implant in such a way that translational and/or rotational movements are made possible. Furthermore, the contact surface between the cover plate and the disk located between the vertebrae is semi-cylindrical such that the contact surface is maximized.

Description

Intervertebral implant

description

The present invention relates to an intervertebral implant comprising a cover plate and a base plate and a cylindrically configured articulating surface between the cover plate and the intervertebral disk, which tilt only by rotation about the lateral axis and thus a tilting movement due to rotation about the lateral axis only in anterior allows posterior direction. By this embodiment, the natural freedom of movement of a spinal column segment is best modeled.

The spine represents the physical center of movement of the human body. It carries the body weight, is capable of complex movements and able to absorb and balance the forces acting on it.

The human spine consists of a total of 24 vertebrae, the sacrum and the coccyx. The individual vertebrae are going through

Intervertebral discs, the intervertebral discs separated. The spine is divided into five sections, namely the cervical spine (7 cervical vertebrae, C1 - C7), the thoracic spine (12 thoracic vertebrae, Th 1 - Th 12), the lumbar spine (5 lumbar vertebrae, L1 - L5), the sacrum and the coccyx.

Each vertebra consists of a bony vertebral body, a vertebral arch spanning the spinal cord, one transverse process and one posterior spinous process on each side.

In the medical disciplines of surgery, orthopedics and neurosurgery, artificial disc replacement of traumatically, rheumatically or degeneratively modified spinal columns is part of the surgical interventions.

The state of the art is to stiffen the spine in the loaded area. With plate or bar materials, painful regions are bridged, which stiffen over time due to lack of movement. Usually, the stiffeners are ventral (lying to the abdomen, on the side of the vertebrae or dorsally (belonging to the back, lying to the back) in the area of the vertebral arches (pedicles).

For the artificial replacement of the intervertebral disc, the body's own material (annulus fibrosus and nucleus pulposus) is surgically removed and a placeholder is used instead. Here mostly rigid cages are used, which are filled depending on the system with bone cement or with bone chips.

Disadvantages of the known systems are that a stiffening / fusion of the respective movement segment is accepted for the treatment of the symptoms. A restoration of the spine in shape and function is not achieved. The result of such procedures is limited mobility and adjacent disc syndrome, which overloads the intervertebral disc space adjacent to a fusion because it must carry the resulting movement forces from the stiffened segment.

In recent years, systems have been developed which aim to maintain the mobility of the vertebral segments and not rigidly connect the two vertebrae in the area of the defective disc. Such systems mainly use viscous or deformable material surrounded by a rigid outer shell.

US 2002/0128715 A1, for example, discloses an artificial intervertebral disc which consists of a deformable, elastic inner body, which can be deformed within certain predefined limits and is surrounded by a rigid outer skeleton. By this artificial disc, the natural degrees of freedom of movement are achieved by a predetermined limited deformation of the inner body.

The imitation of the movement possibilities of a natural vertebral segment can be improved in all known artificial intervertebral discs. It has not yet been possible to give an artificial spinal disc implant the degrees of freedom of movement given to a natural vertebral segment. Due to the defective function of the known implants, the mobility of the spine is not optimally restored. Imbalanced load peaks during the movement provoke the sinking of the implants into the vertebral body. Furthermore, in the known systems, the problem arises either they are not load-stable and do not do justice to the sustained loads acting on the spinal column, or the materials do not meet the requirements with regard to biocompatibility. In addition, the growth behavior is still insufficient and these processes can lead to renewed pressure on the nerve root.

Several of the aforementioned disadvantages of the prior art have already been overcome by the Applicant's invention, which is the subject of German Patent DE 103 61 772 and European Patent Application EP 04803009.2. The German patent DE 103 61 772 discloses an intervertebral disc implant, comprising a base plate, a cover plate and a vortex washer, wherein the intervertebral disk is mounted on the base plate, that translation and rotational movements are possible and the cover plate is mounted on the intervertebral disk that the articulating surface of the intervertebral disk and the articulating surface of the cover plate are each on a spherical surface with the same radii. This embodiment is able to ensure a good mobility of the artificial intervertebral disc implant due to the possible translational and rotational movements, but is not yet able to distinguish between the different possibilities of movement in a lateral vertebral segment in the lateral and in the posterior anterior direction.

Object of the present invention is to provide an intervertebral disc implant, which achieves a maximum of anatomical compatibility and the movement degrees of freedom of a natural disc optimally mimicking even under continuous load and thus can replace a natural disc permanently.

This object is achieved by providing an intervertebral implant according to claim 1 and its use according to claim 17. Further advantageous embodiments, aspects and details of the invention will become apparent from the dependent claims, the description, the examples and the figures.

The present invention relates to a vertebral intermediate implant, comprising a base plate, a cover plate and a vortex washer, which may also be an integral part of the base plate or the cover plate, wherein the Intervertebral disk has the shape of a half-cylinder whose longitudinal axis extends in the lateral direction or extends parallel to the lateral axis.

Since a natural vertebral segment allows, in addition to the rotational movement and the translational movement to some extent, arise complex movement patterns, which can be modeled only by intervertebral implants, which allow different forms of movement to varying degrees in defined directions.

Such kinematic movements are not capable of the conventional disc implants of the prior art. However, the intervertebral implants according to the invention are designed in such a way that tilting movements in the lateral direction are prevented and admitted in posterior (backward) and anterior (forward) directions. At the same time, translatory movements in the lateral direction are preferably made possible and largely prevented in the posterior and anterior direction. However, according to the invention, the inter-vertebral implants described herein permit such forms of motion that the physiological movement pattern can be very accurately imitated.

The intermediate intervertebral implants according to the invention, which may also be referred to as artificial intervertebral discs, are preferably constructed in three parts, i. from a cover plate, a base plate and a separate intervertebral disk. However, the intervertebral implants according to the invention can also be designed in two parts. In such a case, the intervertebral disk is firmly connected to the base plate or the cover plate and forms a unit with this. such

Vertebral intermediate implants are in two parts and consist of a base plate, which contains as an integrated Bestanteil the intervertebral disk and a cover plate. Of course, it is also possible to integrate the intervertebral disk in the cover plate, so that such intervertebral implants consist of cover plate with integrated intermediate intervertebral disk and base plate.

Is in the two-part embodiments, the intervertebral disk integrated into the base plate or firmly connected to this, of course, no

Relative movement of base plate to integrated or firmly connected

Intervertebral disk take place. The same applies if the Intervertebral disk is firmly connected to the cover plate or integrated in this.

However, preferred are the three-part embodiments of the intervertebral intervertebral discs according to the invention, as these translational movement of the intervertebral disk with respect to the base plate and a rotational movement of the intervertebral disk with respect to the cover plate or just a translational movement of the intervertebral disk with respect to the cover plate and a rotational movement of the intervertebral disk with respect to the Base plate is possible. As will be explained in more detail below, rotational movement can not be 360 degrees. Of course, rotational movement and translational movement are only possible to a limited extent, as well as a natural vertebral segment can move.

In order to allow the limited rotational movement about the lateral axis, the articulating surface of the intervertebral disk according to the invention is designed semi-cylindrical.

FIG. 2 shows the semi-cylindrical intervertebral disk according to the invention. By the term semi-cylindrical is meant a plano-convex form, i. a plane surface and a cylindrical surface with a defined radius.

Thus, in the three-piece embodiment of the intervertebral intervertebral implant according to the invention, the intervertebral disc has a planar articulating surface for translational movement and a semi-cylindrical articulating surface for performing rotational or tilting movements with respect to the respective base plate or cover plate.

In the two-part embodiment of the intervertebral implant according to the invention eliminates the plane articulating surface and the possibility of translational motion, because on this surface, the intervertebral disk with the respective plate (base plate or cover plate) is firmly connected, so that a total of a base plate or a cover plate with a semi-cylindrical articulating Area results.

The ends of the half-cylinder may also be flat, that is, just as you would define a half-cylinder, or designed as a cone attachment or as a ball attachment. The cone top can be the cone tip preferably rounded or spherical. In Figure 2, the ends, ie the side surfaces of the half-cylinder are designed spherical.

Furthermore, it is essential to the invention that the vortex washer designed as a half-cylinder is arranged along or parallel to the lateral axis, so that the rotational or tilting or tilting movements in the retroflexing direction

(anterior) and in anteflexion direction (posterior) is possible, but not in the lateral direction. This means that around the lateral axis a turning, tilting,

Tilting or rotational movement is possible to some extent, but not to the retroflexion-anteflexion axis and of course not to the axial axis.

In Figure 1, the axes are shown in a spinal column segment. The axial axis is the axis along the spinal column, the retroflexion anteflexion axis is the axis running through the abdomen and back and the lateral axis is the axis perpendicular to the axial axis and perpendicular to the retroflexion anteflexion axis.

The present invention thus relates to two-piece or preferably three-part intervertebral implants comprising a base plate, a cover plate and an integrated or separate intervertebral disk, wherein the intervertebral disk has the shape of a half-cylinder, the longitudinal axis extending in the lateral direction.

The intervertebral disk thus has a plane articulating surface, which preferably rests plan on the base plate but can also rest flat on the cover plate in another embodiment. The semi-cylindrical articulating surface of the intervertebral disk is located in a corresponding recess of the cover plate or in the other embodiment in a corresponding recess of the base plate.

In embodiment A, the intervertebral disk thus lies with its surface articulating surface on a likewise plan designed articulating surface of the base plate. The base plate is also designed so that it can be attached to the underlying vertebral body, with any common configurations for attachment are possible, which are not essential to the invention and therefore not further elaborated. All known for vortex shims mounting options can also be used in the intervertebral discs invention. The semi-cylindrical articulating surface of the intervertebral disk is in a corresponding semi-cylindrical recess of the cover plate. In other words, the convex articulating surface of the plano-convex intervertebral disk lies in a correspondingly concave recess in the cover plate, so that a sliding, tilting, tilting or rotational movement of the cover plate on the intervertebral disk about the lateral axis is possible.

In all embodiments, it is highly preferred if the radii of the semi-cylindrical articulating surface of the intervertebral disk and the

Radius of the semi-cylindrical recess in the cover plate (embodiment A) or in the base plate (embodiment B) are identical or nearly identical.

Almost identical means that the semi-cylindrical recess must of course be slightly larger than the semi-cylindrical intervertebral disk, so that a rotational, tilting, tilting or rotating movement is possible. That both

Radii can not be absolutely identical, the expert is aware.

Figure 6 and Figure 7 show a cover plate with a semi-cylindrical recess, wherein the side surfaces of the half-cylinder are not flat, but leak in a spherical part surface or a hemisphere.

The term "half-cylinder" is understood to mean a cylinder cut along its longitudinal axis, wherein the cylinder does not necessarily have to be cut through in the middle, ie where the resulting flat surface has the largest diameter, but can be cut through in the middle region, where the resulting flat surface does not have the largest possible diameter. However, it is preferred that the intervertebral disk as part of the entire cylinder represents the smaller piece, i. the cutting has taken place above the central surface and not below the central surface of the cylinder.

The cover plate, of course, also has means for attachment to the overlying vertebral body, which are also not essential to the invention, may have a conventional design and will not be further elaborated.

In the embodiment B, the cover plate lies with its plan articulating surface on the plan articulating surface of the intervertebral disk and the semi-cylindrical articulating surface of the intervertebral disk is inserted into a corresponding recess in the base plate.

Thus, embodiments A and B differ only in that in embodiment A, the rotational, tilting, tilting or rotating movement between the intermediate vortex disc and the cover plate and in the embodiment B, the rotational, tilting, tilting or rotational movement between the Intervertebral disk and the base plate takes place, wherein embodiment A is preferred.

In order to better imitate the natural movement patterns of a spinal segment, translational movements of the intervertebral disk on the base plate (embodiment A ') or in relation to the cover plate (embodiment B ¹ ) are provided in further preferred embodiments.

The translational movements of the intervertebral disk relative to the base plate are independent of the possible rotational, tilting, tilting or rotational movements of the cover plate relative to the intervertebral disk. Thus, relative to each other all three parts of the intervertebral implant according to the invention can be moved, whereby the natural degrees of freedom of movement of the spine can be mimicked as best as possible.

The mounting of the intervertebral disk on the base plate in such a way that Tanslationsbewegungen intervertebral disk and base plate relative to each other are possible, can be realized in various ways.

One implementation possibility involves the use of fastening means. As fasteners come cones, bulges, half cylinders, brackets, pins, flanges and the like, and other conceivable means for limiting the translation movement of intervertebral disk on base plate in question, which are preferably mounted on the base plate. The base plate can also be provided only with or in addition to an edge which surrounds the base plate at least partially and can be designed segmented, jagged, wavy or continuous. In addition, various fasteners may be combined with each other, and two, three, four, five, six or more fasteners such as pins, bosses, brackets, pins, flanges and the like may be provided. In particular, fastening means are preferred, which are completely covered by the intervertebral disk. On the base plate or on the edge of the base plate mounted lateral boundaries in the form of, for example, edges, brackets, beads, rails or the like are less preferred because they represent a point of attachment for tissue and can be overgrown with trades and / or cartilage, whereby the mobility of Intervertebral disk on base plate is limited again. Thus, in particular, fastening means are preferred which are completely concealed, ie are not accessible to tissue, cartilage and muscles. Completely hidden are the fasteners, for example, if they are located inside the implant, for example, be covered by the intervertebral disk.

Figures 4 and 5 show a base plate of a preferred embodiment of the invention (A ') with two preferably centered pins arranged. Accordingly, the intervertebral disk has one or two recesses for receiving these pins. Figure 3 shows a vortex washer with an elongated and slightly anteriorly curved recess for receiving the two pins of the base plate, wherein preferably the recess is longer than the distance between the two pins to each other, so that a translational movement of the two pins in the recess in the lateral direction possible is.

Figure 11 shows a vortex washer with an elongate cylindrical recess on the flat surface. The base plate has a corresponding semi-cylindrical elevation, which is shown in Fig. 13, which fits into the recess in the intervertebral disk, wherein the increase on the base plate is shorter than the length of the recess in the intervertebral disk, so that a translational movement of the intervertebral disk on the base plate of a few millimeters is made possible. The term "length of the increase" refers to the length of the axis of rotation, if one would regard the increase on the base plate as a cylinder. As the "length of the recess" in the intervertebral disk, the length of the axis of rotation is called, if one would consider the recess as a cylinder. These lengths then correspond to the height of the cylinder. In order to allow a translation movement of the intervertebral disk on the base plate, the height of the cylinder of the increase must be smaller than the height of the cylinder of the recess. The height difference is the distance, which can translate the intervertebral disk on the base plate from one extreme point to the other. Instead of a half cylinder as an elevation on the base plate, such a limitation of the translational movement in the lateral direction can also be realized by two pins or two hemispheres or two cones or the like on the base plate, which are spaced apart from one another by less than the height defined above Cylinder of the recess in the intervertebral disk.

FIG. 12 is a further preferred embodiment of the embodiment according to the invention according to FIG. 11, with the difference that the recess in the intervertebral disk and, correspondingly, the elevation on the base plate are slightly bent. The radius of curvature of the increase on the base plate as well as the recess in the intervertebral disk is in the range of 10 mm to 100 mm, preferably between 30 mm and 80 mm and particularly preferably between 40 mm and 70 mm. Again, as described for FIGS. 11 and 13, the length of the elevation on the base plate is shorter than the length of the recess in the intervertebral disk. As a result, a lateral translational movement is also possible in the embodiment according to FIGS. 12 and 14, but not along a straight line but rather on a slightly curved curved path. If one now considers the entire implant, FIG. 16 shows the embodiment of the implant according to the invention according to FIGS. 12 and 14 with a cover plate inclined relative to the base plate, wherein the cover plate is also displaced in translation relative to the base plate. It can be seen that base plate du cover plate are not moved along a straight line parallel to each other, but have been shifted to each other on a curved path, because the lateral posterior areas of the cover plate protrude beyond the lateral posterior areas of the base plate.

The base plate may thus have one or more preferably centered mounted guide and / or receiving pins extending in the direction of the axial axis. Instead of the centered positioning of the guide and / or receiving pin (s) and decentralized, for example, dorsal or ventral offset be attached. Preferably, the pins have a diameter of from 2 to 15, preferably from 3 to 12 mm, more preferably from 5 to 10 mm and especially preferably from 6 to 9 mm and a height from 1 to 5 mm, preferably from 2 to 4 mm and in particular preferably from 3 to 4 mm. Furthermore, such a pin preferably has a cylindrical shape or conical shape, but with generally ellipsoidal forms can be used. A single pin should be mounted largely centered on the base plate and two pins should in principle each have the same distance to the outer edge of the base plate, so be arranged symmetrically in a sense.

According to the invention, the intervertebral disk has a recess suitable for receiving the pin or pins and preferably the two pins or the fastening means, wherein this recess should have a larger diameter than that of the pins. Such a recess is preferably oblong shaped and further preferably bent banana-shaped slightly towards the abdomen (anterior). Instead of an elongated recess for receiving two pins and two individual recesses may be provided, which are preferably round, O-shaped to ellipsoidal and the 1, 2-fold to 5-fold, preferably 1, 5-fold to 3.0 Have a diameter of the pin to allow a translational movement. For oval single recesses, the longer diameter of the oval or ellipsoid extends along the lateral axis.

Due to the larger design of the respective recess in the intervertebral disk in comparison to the respective pin of the base plate, the respective pin can be set in the limits defined by the recess or the

Intervertebral disk translates within these limits on the

Move base plate. The recess or the recesses in the

Intervertebral discs are preferably designed so that, overall, a translational movement of the intervertebral disk on the base plate is made possible in the lateral direction, regardless of whether the recess contains one or more pins.

Preference is given to an approved translatory movement in the lateral direction, wherein a smaller translatory movement in the anterior and posterior directions can also be permitted. The translational movement in the anterior and posterior directions, however, should only amount to one tenth to a maximum of one fifth of the path of the translational movement possible in the lateral direction.

If these relations are reproduced in absolute numbers, then the intervertebral disk on the baseplate can preferably be from a centered position 0 to 5 mm, preferably 0.5-3 mm, more preferably 1 to 2.5 mm and particularly preferably 1.5. 2.0 mm in the lateral direction and 0 to 1 mm, preferably 0.1 - 0.75 mm, more preferably 0.15 - 0.5 mm and particularly preferably 0.2 - 0.3 mm move in the anteflexion as well as in the retroflexion direction. This information refers to the distance from the centered position to an extreme position. The double distances are traveled from an extreme position to the other extreme position.

Depending on the size of the implant, which depends on which vertebrae the intervertebral implant is to be inserted, the intervertebral disk may have different thicknesses, which may be 3 mm, 6 mm, 9 mm or 12 mm, for example. Further, the intervertebral disk is preferably non-deformable and made of a hard material such as PEEK [poly (ether ether ketone)], UHMWPE or a metal such as e.g. Titanium or titanium oxide or a ceramic.

A further preferred embodiment according to the invention comprises two pins, which are preferably mounted centrally on the base plate or mounted dorsally or ventrally offset. The intervertebral disk accordingly has two recesses, which have a larger diameter compared to the diameter of a pin. As a result, the intervertebral disk can move freely within the recesses around the pins, wherein the translational movement as well as the rotational movement about the axial or anatomical axis in the context of the recesses is possible. In this embodiment, of course, a free rotation of 360 degrees is not possible.

Figures 11, 12, 13 and 14 show two preferred embodiments of a three-part implant, wherein the base plate and cover plate on the side facing the bone are serrated and roughened to allow a better ingrowth into the bone. In Fig. 11 is an elongated or semi-cylindrical recess on the flat surface in the intervertebral disk to see. Furthermore, the partially cylindrical recess in the base plate can be seen, which serves to receive the partially cylindrical surface of the intervertebral disk. In the corresponding FIG. 13, the implant is viewed from another angle, and the underside of the base plate and the surface of the cover plate facing the intervertebral disk are discernible. On this surface of the cover plate is a cylindrical elevation with spherical lateral side surfaces to recognize, with this survey the Intervertebral disc comes to rest. The cylindrical elevation has largely the radius of the recess in the intervertebral disk, but is not as long as the recess in the intervertebral disk, so that the intervertebral disk can translate in the lateral direction on this cylindrical elevation. This embodiment according to FIGS. 11 and 13 permits only a translatory movement in the lateral direction and only one tilting movement in the anterior-posterior direction and thus limits the degrees of freedom of movement in relation to the spatial orientation.

Figures 12 and 14 show another preferred three-part embodiment wherein the recess in the intervertebral disk is banana-shaped, i. has the shape of a bent cylinder. The elevation on the cover plate has a corresponding shape, but does not completely fill the recess in the intervertebral disk, i. the recess in the intervertebral disk is longer, so that a curved sliding movement of the intervertebral disk on the cover plate is made possible. This results in a mobility in the lateral direction, but not on a straight line, but on a curved path.

In all embodiments, however, the part-cylindrical surface of the intervertebral disk, which allows the tilting or tilting movement, is strictly cylindrical, i. not bent, such as a banana, because only a cylinder surface or cylinder surface allows tilting or tilting movement.

The movements possible according to the two embodiments shown in FIGS. 11 and 13 as well as 12 and 14 are shown in FIGS. 15 and 16. Figure 15 corresponds to the embodiment according to Figures 11 and 13 and shows the implant in an anterior inclined shape (i.e., ventral approximated plates and dorsal plates dilated), wherein the base plate and cover plate are not displaced in the lateral direction against each other.

FIG. 16 shows an implant according to the invention according to FIGS. 12 and 14 in a posteriorly inclined position, the base plate and cover plate being displaced laterally relative to one another. Since the elevation on the cover plate is designed semi-banana-shaped, the cover plate relative to the base plate is not displaced against each other along a straight line, but the displacement against each other takes place along a curve. Thus, in Fig. 16 to recognize that the cover plate and the base plate are anteriorly inclined away from each other, wherein due to the lateral translational movement along a curve, cover plate and base plate are no longer side surface parallel to each other, but the cover plate is slightly rotated relative to the base plate.

Instead of two pins, three or more can be used, which are usually mounted at regular intervals on the base plate. Furthermore, lateral brackets can be provided instead of pins. In this case, the limited by the laterally attached to the base plate holders base surface of the base plate is designed to be larger than the resting bottom surface of the intervertebral disk, so that the intervertebral disk translational and / or rotational movements on the base plate or relative to the base plate can perform and indeed in the context of lateral mounts. Such mounts may be, for example, a solid or discontinuous, straight or wavy bead on the edge or a raised edge.

According to the invention, the semi-cylindrical articulating surface is mounted on the semi-cylindrical surface of the articulating plate (cover plate: embodiment A, A ', base plate: embodiment B, B') in such a way that the articulating surfaces of both implant parts lie on a cylindrical part surface.

By "articulating surface" is meant the surface of the intervertebral disk or the surface of the cover plate (embodiment A, A ') or the base plate (embodiment B, B'), which may come into contact with the respective other surface in the possible movements ,

These interacting articulating surfaces of the intervertebral disk and the cover plate or base plate lie on a portion of the surface of a cylinder.

The contact surface is to be understood as the area where, at a certain frozen position, the intervertebral disk and the cover plate (embodiment A, A ') or the intervertebral disk and the base plate (embodiment B, B') both parts come into contact with each other. Thus, the contact surface of the intervertebral disk with the cover plate (embodiment A, A ') or the intervertebral disk with the base plate (embodiment B, B') is located on a partial surface of a cylinder.

The articulating surface of the cover plate (Embodiment A, A ') also corresponds to the contact surface and in the embodiment B and B' corresponds to the articulating surface of the base plate of the contact surface.

The radii of the half cylinders, i. the contact surfaces as a partial surface of a cylinder of intervertebral disk and associated articulating plate have orders of magnitude of R = 15 - 45 mm. The radii increase according to the size of the disc implant. Radiopaque implants for the lumbar region have radii of 25-45 mm, for the thoracic region of 20-40 mm and for the cervical region of 15-35 mm.

The contact area is at least one area of 500 mm ² , preferably of at least 600 mm ² , more preferably of at least 700 mm ² and particularly preferably of at least 800 mm ² . Again, it should be noted that the contact area depends on the size of the implant and larger intervertebral implants also have a larger contact area. Contact surfaces of this size distribute the mechanical load on the intervertebral disk and lead to a longer life of the implant.

This embodiment of the invention, the contact surface between the cover plate and intervertebral disk is maximized even with complex movements, since no point-shaped or linear contact surface, but a cylindrical contact surface is obtained.

In principle, two embodiments are conceivable. On the one hand, the articulating surface of the cover plate convex or plano-convex and articulating the cover plate surface of the intervertebral disc concave or plano-concave or the articulating surface of the cover plate is concave or plankonkav and articulating with the cover plate surface of the intervertebral disc convex or plano-convex formed, the latter variant is preferred. Both the first and the second variant, there are another two possible embodiments, namely, in variant 1, the concave vortex washer with a convexly configured Articulate cover plate or with a convex designed base plate, while in a preferred variant 2, the convexly configured intervertebral disk with a concave cover plate (embodiment A, A ') or with a concave designed base plate (embodiment B, B') can articulate. In this case, the concave or convex configurations continue to be the semi-cylindrical configurations, ie the radius of the rounding remains unchanged. The terms concave and convex are used only to indicate the direction of curvature of the semi-cylindrical configuration.

A preferred embodiment of the intervertebral implant thus comprises a base plate, a vortex washer and a cover plate, wherein the intervertebral disk is mounted on the base plate, the limited translational and / or rotational movements are possible and the cover plate (embodiment A ') is mounted on the intervertebral disk in that the articulating surface of the intervertebral disk as well as the articulating surface of the cover plate lie on a respective partial surface of a cylinder, the cylinders having the same radii.

A further preferred embodiment of the intervertebral implant thus comprises a base plate, a vortex washer and a cover plate, wherein the intervertebral disk is mounted on the cover plate, the limited

Translational and / or rotational movements are possible and the base plate

(Embodiment B ') is mounted on the intervertebral disk such that the articulating surface of the intervertebral disk as well as the articulating surface of the base plate lie on a respective partial surface of a cylinder, wherein the cylinders have the same radii.

In the embodiments according to the invention, moreover, the cover plate can be tilted up to 20 degrees relative to the base plate from a parallel position to each other. In other words, the cover plate (embodiment A, A ') or even the base plate (embodiment B, B') can up to 20 degrees relative to the base plate (embodiment A, A ') or to the cover plate (embodiment B, B') starting from a parallel position inclined to each other.

Furthermore, cover and base plates are preferred, which taper conically. The cover and base plates are thicker on their ventral side than on their dorsal side to better reproduce the natural shape of a vertebral segment. Cover plate or base plate or cover and base plate preferably have on their ventral side double the thickness, as on the dorsal side. Alternatively, cover plate or base plate or cover and base plate on a slope of 3%, preferably 6% and more preferably 8% from the dorsal to the ventral end. It is particularly preferred if the mutually facing sides of the cover plate and base plate have no chamfer and only the opposite sides of the cover plate and base plate are chamfered. In a further preferred embodiment, either only base plate or only cover plate is tapered. The bevel of the cover plate and / or base plate can be up to 10 degrees, preferably 2 to 8 degrees (ventral wide and dorsally expiring). It is further preferred if, according to the curvature of the spinal column, the bending of the cover plate and / or the base plate is adapted to the physiological conditions, wherein preferably the cover plate in cranial (toward the head) direction has a different degree of angulation than the base plate in the caudal direction (towards the foot) direction. The spine, viewed from the side, describes a double S (kyphosis / lordosis). Especially in the area of the lumbar spine (lordosis), the vertebral bodies are in an angled open angle to each other. To the corresponding

To be able to supply the intervertebral disc compartment ideally, the implant with its cover and base plates should be adaptable to these angular vertebrae. The background here is to provide an ideal force transfer to the implant, to minimize the risk of dislocation of the intervertebral disk and to adjust the ligamentous structures of the spinal column according to physiology. Of course, these aspects would benefit the longevity of the implant. If the intervertebral disc space is filled in accordance with the anatomical structures and the intervertebral disk is ideally loaded, the wear of the polyethylene of the intervertebral disk is reduced. Since a vortex washer made of polyethylene, PEEK or other plastics is most susceptible to wear, a particularly preferred embodiment of the present invention uses a metal swirl washer, optionally coated with a ceramic coating.

It is further preferred if the base plate and the cover plate have a convex curvature of the bone-facing surface. Particularly preferred is the convex curvature of the cover plates to the bone, as well as the vertebral bodies have a curvature (concave) and thus a sintering of the implant can be prevented in the bone. Advantage would be that the bone trabeculae structure would be loaded according to the physiology, more surface would be available for the growth of the bone and the risk of dislocation of the implant would be reduced. The convexity is preferably in a range of 1 - 5mm, ie at the highest point, the survey is up to 5mm.

In addition to the possibility of movement of the cover plate and the intervertebral disk relative to each other, the intervertebral disk and the base plate can be moved relative to each other. The intervertebral disc implant according to the invention is designed in such a way that the intervertebral disk is mounted on the base plate (embodiment A, A ') or on the cover plate (embodiment B, B') such that the intervertebral disk in the horizontal plane is a few degrees about the axial torsion axis (axial axis) can be rotated.

The movement of the base plate and cover plate relative to each other is comparable to a movement of two equal parallel plates, between which there is a half cylinder, i. a cylinder is cut along a surface through its longitudinal axis, wherein the respective plate contacts the cylinder at least along a partial surface of the cylinder surface. The movement of the plates zueinender is similar to the movement of the base and cover plate of the intervertebral implant according to the invention to each other, due to the design of the base and cover plate and intervertebral disk, a lateral flexion movement and preferably a retroflexion movement can be performed only to a lesser extent than one Anteflexionsbewegung.

It is essential to the invention that lateral flexion movements are excluded, since this freedom of movement is also not given in the case of a natural vertebral segment. This is inventively achieved by the design of the intervertebral disk as a half cylinder, whose longitudinal axis extends along the lateral axis. As a result, lateral Beugebewegungen the articulating plate are prevented on the intervertebral disk, because otherwise the articulating plate would have to stand out from the intervertebral disk and this can not be done due to the pressure exerted by the spine. Tilting,. Tilt or rotational movements are therefore possible only on the cylinder part surface and only about the cylinder part surface longitudinal axis, ie about the lateral axis and thus only in retroflexion and Anteflexionsrichtung. If, furthermore, the tilting, tilting or rotational movement about the lateral axis in the direction of retroflexion is allowed to be greater than in the anteflexing direction, then one has the natural forms of movement of a natural vertebral segment so the possibilities of movement between two vertebral bodies replicated as best as possible.

The base and cover plates can rotate up to a maximum of 10 degrees relative to each other, preferably up to 8 degrees, more preferably up to 6 degrees, and most preferably up to 4 degrees.

A retroflective bending movement may be up to 10 degrees, preferably up to 15 degrees, and most preferably up to 20 degrees, from a centered position. Anteflexion bending movement may be up to 20 degrees, preferably up to 25 degrees, and most preferably up to 30 degrees, from a centered position. A bending movement in the lateral direction is not possible.

The intervertebral disk is further preferably designed such that it has a size such that in all possible movements, the cover plate does not touch the base plate. Furthermore, the edges of the cover and base plate have a bend of the facing corners away from each other. This angulation of the edges of the base plate and the bottom plate and the configuration of the intervertebral disk are essential for a long operability of the implants according to the invention, since the touching or rubbing (impingement) of cover on base plate to abrasion and the release of particles up to larger Implant pieces can lead, which reduce the life of the implant drastically. In addition, the case of dislocation of the intervertebral disk can occur when the base and cover plate touch and the contact surface between the cover plate and intervertebral disk is reduced due to a raised cover plate. For the above reasons, it is therefore essential to avoid impingement of the cover and base plate.

Furthermore, the intervertebral disk, i. the intervertebral disc preferably made of a hard plastic such as PEEK or polyethylene and in particular Ultra High Molecular Weight Polyethylene (UHMWPE), wherein titanium can be used with a ceramic coating for the intervertebral disk.

The term "ultra-high molecular weight polyethylene" is ambiguous: HDPE (high density PE) is currently a PE with a molecular weight of less than 200,000 g / mol. According to DIN ISO 11542, PE with a melt mass flow rate of less than 0.1 g / 10 min is defined as UHMWPE (this would correspond to a molar mass of more than 106 g / mol), according to ASTM D 4020 the limit is 3.1 ^* 106 g / mol. The stated mean molecular weight of today's UHMWPEs is between 3.5 * 106 and 107 g / mol, depending on the manufacturer and the measuring method used. Ultra High Molecular Weight Polyethylene (UHMWPE) is a polyethylene according to ISO 5834-2 standard, Chirulen® and TIVAR® Premium are high purity PEUHMW implants for use in endoprosthetics. As preferred articulation partners they are used in artificial hip, knee, elbow and shoulder joints.

The base plate as well as the cover plate and in some embodiments also the intervertebral disk of the implants according to the invention are usually constructed completely from a hard material, in particular a ceramic, a metal or a metal alloy such as titanium, zirconium, oxidized zirconium, hafnium, platinum, rhodium , Niobium, medical grade stainless steel, CoCr steel (Cobalt Crom), tantalum and may also consist of fiber reinforced plastics (glass / carbon fibers with appropriate matrix), PEEK [poly (etheretherketone)] or polymer materials in general. For the metal alloys, metals such as aluminum, medical steel and / or gold may also be added.

In further particularly preferred embodiments, a metal and preferably titanium or a titanium alloy is used to produce the intervertebral disk. In these further preferred

Embodiments which have a base plate made of titanium or a titanium alloy, a cover plate made of titanium or a titanium alloy and a swirl intermediate plate made of titanium or a titanium alloy, so-called hard-hard pairings result between the cover plate and intervertebral disk as well as between the base plate and intervertebral disk. In these systems, it is also particularly preferred if the titanium or the titanium alloy is provided with a ceramic coating. In principle, embodiments are also possible which do not use plastic for the intervertebral disk but a metal or a metal alloy, which is preferably still provided with a ceramic coating. The titanium materials approved for medical technology should in particular comply with DIN ISO 5832-3. In principle, the approval of titanium and titanium alloys as medical material is regulated according to DIN ISO 5832-1 to 5832-12 standards.

In addition to pure titanium, titanium alloys such as Ti-6AlV, Ti-Nb-Ta-Zr, Ti-Al6-Nb7 (according to ISO 5832-11) or Ti-29Nb-13Ta-4.6Zr can thus also be used according to the invention. Titanium alloys are preferred in which the titanium content is at least 50% by weight, more preferably 65% by weight, even more preferably 80% by weight and most preferably 90% by weight. Further, the use of pure titanium or coated or uncoated CoCr alloys to make the entire disc implant is preferred.

The base and bottom plates may be cemented or cementless implanted into the bone or attached to the vertebral bone, with cementless anchoring being preferred.

Furthermore, titanium is preferably used as the material for the base body of the base and / or cover plate. Titanium as the base material of the base and cover plate according to the invention is biologically inert, therefore it grows firmly on the bone, can be cemented without cement and is not allergenic.

By choosing biocompatible, inert materials, the acceptance of the physiological tissue on the implant is substantially improved. Due to the use of materials that are particularly suitable to withstand tribological stresses, the wear of the artificial material is minimized and thus significantly increases the life (life) of the implant.

Bone cells can anchor directly to biocompatible materials if they have a textured surface whose open roughness ranges from 50 to 400 μm.

In order for the base and cover plate to grow together firmly with the bone, in particular in the case of cement-free fastening, the surface of the base plate as well as the cover plate facing the bone has a roughness of at least Rz 50 μm, preferably of at least Rz 60 μm. Of course, other degrees of roughness can be used, including spongiosa metal.

The roughness is indicated either as Rz or Ra (DIN 4762, 4768, 4775, ISO 4288). Rz denotes the average roughness depth. The average roughness

Rz is the arithmetic mean of the largest single roughness depths of several adjoining individual measurement sections. Ra, however, rough value the arithmetic centers. Ra is the generally recognized and internationally applied roughness parameter. It is the arithmetic mean of the absolute values of profile deviations within the reference distance. The measured value Ra is always smaller than the one on the same

Roughness profile determined Rz value.

The base and / or cover plate of the disc implant according to the invention are preferably coated with a metallic or ceramic coating, which may have a variable number of individual layers or a different layer thickness. Ceramic coatings include nitrides, carbides and phosphides of preferably semi-metals and metals or metal alloys. Examples of ceramic coatings are boron nitrides, titanium-niobium nitride, titanium-calcium-phosphide (Ti-Ca-P), Cr-Al-N, Ti-Al-N, Cr-N, TiAIN-CrN, Ti-Al-. C, Cr-C, TiAIC-CrC, Zr-Hf-N, Ti-Hf-CN, Si-CN-Ti, Si-CN and DLC (Diamond Like Carbon). As a coating, a ceramic layer of titanium-niobium nitride (Ti-Nb-N) is also preferably applied.

In particular, it is advantageous if the articulating surface of the base and the cover plate with titanium niobium nitride (Ti-Nb-N) is coated.

This ceramic coating of the particular articulating implant surfaces has a hardness that is many times higher than that of conventionally used materials. Due to this hardness, the surface is highly polishable and protected against titanium abrasion.

According to the invention, the geometry of the articulating compartments is chosen such that the areas exposed to the decay can be maximized. This means that according to the invention, the geometry of the joint partner is chosen so that a flat contact surface between the base plate and intervertebral disk (embodiment A, A ') or between the cover plate and intervertebral disk (embodiment B, B') and a cylindrical surface section between the intervertebral disk and cover plate (embodiment A, A ') or between intervertebral disk and base plate (embodiment B, B'), the tribologically loaded surfaces are maximized, which ultimately reduces the wear of the implants of the invention. This results in a reduction of the effective forces per unit area, which in turn has a positive effect on the life of the implant by reducing the abrasion. By the selected and adapted to the individual case geometry of the intervertebral implant, in particular the geometry of the intervertebral disk, and the correct placement of the implant in the operation, the physiological mobility of the vertebral segments is met to best possible. This nearly perfect imitation of a natural disc or its mobility significantly reduces the forces acting on the bone-implant interface, which has a positive effect on the longevity (reduction of wear and minimization of loosening) of the implant.

The prostheses of the prior art can usually be used only on a maximum of two floors in the back. The invention

Intervertebral implants can also be used on more than two levels in the spine. The individual intervertebral implants are adapted to the size and geometry of their respective situation, so that spinal disorders, spinal injuries as well as spinal disorders can be treated by such multiple implants.

Such spinal disorders, spinal injuries as well as spinal disorders which can be treated by an intervertebral implant according to the invention or by a set of intervertebral implants according to the invention include, for example, scoliosis, i. the lateral curvature of the spine, also called spinal curvature, disc herniation, which means the emergence of the nucleus disc against the adjacent vertebral bodies or the nerve roots and kyphosis, which refers to the curvature of the spine to the rear.

Furthermore, the following spinal disorders, spinal injuries as well as spinal disorders can be treated by the intervertebral implants according to the invention: Discus fracture (ie disc damage), black disc (degenerative disc, which appears black in the X-ray), spontaneous deformation, ie the deformation of vertebral bodies by diseases, bone changes or tumors, lumbago or commonly referred to as lumbago or lumbar pain, of which one violent, usually sudden understands occurring pain in the crura and lumbar region. Lumbago is most commonly caused by changes in the intervertebral discs. Spondylosis deformans, ie disease of the vertebral bodies and intervertebral discs with severe pain in motion, widow's hump, which is a spinal curvature in older women, caused by bone loss due to the altered hormonal position after the climaterium (menopause), spondylomyelitis, ie inflammation of the vertebrae and spinal cord, osteochondrosis, what describes the alteration and degeneration of intervertebral discs, as well as osteofibrosis, which refers to the disorders of the skeleton in adolescents, spina bifida also known under crevice vertebrae, especially the congenital clefting of the spine, lordosis, among which the expert

Curvature of the spine forward, caused by a hollow back understands Spondylotosis, ie the sliding of a vertebral body by a whole vertebral width, usually the 5th lumbar vertebra on the sacrum, Schipper disease, which caused by heavy overexertion break, mostly the 7th cervical or of the 1st thoracic spinous process referred to, myelomeningocele, by which the skilled person understands the congenital deformity of the vertebral arches, brachialgia, which refers to the pain in the arms and shoulders due to changes in the cervical vertebra, Baastrup sign, causing the bending of the spine forward with broadening the spinous processes and crushing of the intervening tissue, which is usually associated with severe low back pain and pressure pain of the spinous processes, vertebral ankylosis, refers to the bony stiffening of the spine with severe pain in the trunk, arms and legs and paralysis of the limb muscles, Scheuermann disease, with which the expert bone and cartilage inflammation of the individual vertebral bodies, preferably the thoracic spine in adolescents, cervical syndrome, ie diseases of the soft tissues in the cervical spine, lumbar kyphosis, ie curvature of the spine in the lumbar vertebrae, torticollis, ie torticollis, often Rheumatism-related as well as the Bechterew disease, which means the chronic inflammatory spinal disease, which leads to changes and stiffening of the entire spine apparatus. figure description

FIG. 1 shows two vertebrae with vertebral body, vertebral canal, vertebral arch, transverse process, spinous process and the associated intervertebral disks and the axes along and perpendicular to the spinal column;

Figure 2 shows a vortex washer with inventive semi-cylindrical shape, wherein the two ends or side surfaces are configured not spherical but spherical or more precisely quarter spherical; Figure 3 shows the intervertebral disk from its plane side, the quarter-spherical ends or side surfaces are clearly visible and also the recess for receiving the guide pins of the underlying or resting plate can be seen, the recess oblong and slightly bent towards the belly so ventral is;

Figure 4 shows a base plate with two pins or guide pins, which are received in the corresponding recess in the intervertebral disk, wherein the base plate is designed plan and thus result in flat articulating surfaces, the intervertebral disk can be mounted movable in translation on the base plate;

FIG. 5 shows a base plate with two centrally arranged pins. The base plate is rectangular with rounded edges, this shape is not mandatory and round, oval or asymmetrical shapes can be used;

Figure 6 shows a cover plate, wherein the semi-cylindrical recess for

Picture of the semicylindrical articulated articulating

Surface of the intervertebral disk is shown. It can also be seen that the recess along the longitudinal axis thus extends the lateral axis of the cover plate and thus tilt or

Rotational movements about the lateral axis are possible; Figure 7 shows the cover plate from its underside with the elongated semi-cylindrical recess as an articulating surface for receiving the semi-cylindrical articulating surface of the intervertebral disk;

FIG. 8 shows a three-part intervertebral implant according to the invention comprising a base plate with two centrally arranged cylindrical pins, a semi-cylindrical intervertebral disk with quarter-spherical side surfaces and an elongated recess on the planar articulating surface (not shown) for receiving the two pins of the base plate and a cover plate with corresponding semi-cylindrical recess for receiving the semi-cylindrical articulating surface of the intervertebral disk;

Figure 9 shows the same embodiment of the invention as Figure 8, wherein in Figure 9, the elongated and slightly ventrally curved recess in the plane articulating surface of the intervertebral disk is visible; Figure 10 shows schematically an inventive implant with intervertebral disk with flat side surfaces in an inclined or tilted position, wherein the size ratios and shape of cover plate, intervertebral disk and base plate are abstracted and do not correspond to the actual conditions; FIG. 11 shows an embodiment according to the invention of a three-part intervertebral implant with a semi-cylindrical shape

Intervertebral disk for a directed tilting movement, which has on its flat surface a semi-cylindrical or channel-like recess for the support and for a limited lateral translational movement; the semi-cylindrical or channel-like recess in the intervertebral disk is straight, i. without curvature and serves to accommodate the semi-cylindrical elevation on the base plate (not shown, but visible in Figure 13), wherein the length of the semi-cylindrical elevation on the base plate is shorter than the length of the recess in the intervertebral disk, so that in the lateral direction, the intervertebral disk on the

Base plate can be moved to the respective stop of the increase;

Figure 12 schematically shows an embodiment according to the invention, which corresponds to that of FIG. 11, with the difference that the recess in the intervertebral disk is not rectilinear but curved, whereby a slightly curved translational movement in lateral

Direction is enabled;

FIG. 13 shows the embodiment according to the invention according to FIG. 11 from a different perspective, so that the semi-cylindrical elevation or

Increase on the base plate is recognizable, which rests against the flat surface of the intervertebral disk, wherein the semicylindrical projection shown in the plate in the recess in the Intervertebral disc comes to rest and can be translationally moved in a lateral direction; FIG. 14 schematically shows the same embodiment as FIG

Base plate is shown as the uppermost component and the cylindrical but slightly curved elevation on the base plate can be seen, which in the corresponding recess in the

Vortex disc comes to lie so that a translational

Movement on a slight circular path in the primarily lateral direction is made possible; FIG. 15 shows the embodiment according to the invention according to FIGS. 11 and 13 in the assembled and after state; Figure 16 shows schematically;

embodiments

Preferred embodiments of the intervertebral implant according to the invention will now be discussed with reference to the examples, it being understood that the discussed examples represent advantageous embodiments of the invention, but do not limit the scope of protection to these embodiments.

example 1

One embodiment of an intervertebral implant according to the invention consists of a cover plate as shown in FIGS. 6 and 7, a vortex washer as shown in FIGS. 2 and 3, and a base plate as disclosed in FIGS. 4 and 5.

The intervertebral implant has a size suitable for replacement of a L3 / 4 vertebral segment. Smaller embodiments of the intervertebral implant described in Example 1 are to be prepared without problems by a person skilled in the art. In these smaller embodiments, the contact surfaces, in particular between the intervertebral disk and the cover plate but also between the intervertebral disk and the base plate corresponding to the size of the smaller embodiments can be correspondingly smaller. The same applies to the values given above for the translational movements in lateral as well as retroflexion anteflexion direction.

The cover plate consists of titanium used in medical technology. The bone-facing surface of the cover plate is rough, so that ingrowth or growth of bone cells is made possible. The roughness Rz is about 60 ± 5 microns. The articulating surfaces of the cover plate is half-cylindrical plano-concave designed as shown in Fig. 6 and coated with a ceramic layer of Ti-Nb-N. The layer thickness is 3 - 5 microns.

The articulating surface of the cover plate lies on a cylindrical surface with a radius of R = 25 mm.

The base plate is also made of titanium and has a shape as shown in Fig. 4. The bone-facing surface of the base plate is rough designed with a roughness Rz of about 60 ± 5 microns. The bearing surface for the Intervertebral disk is coated with a ceramic coating of Ti-Nb-N. The layer thickness is 3 - 5 microns.

As Fig. 4 illustrates, the intervertebral disk facing surface of the base plate is planar, except for the two centrally disposed cylindrical

Pencils. The pins have a cylindrical shape with a height of 5 mm and a diameter of 7 mm. Also the pins are with a ceramic

Coating of Ti-Nb-N provided. The baseplate is shown rectangular, of course it can also have other contours and vary in thickness, i. be thicker on the ventral side than on the dorsal side.

The intervertebral disk has a shape as shown in FIGS. 2 and 3. Fig. 9 shows the bottom surface of the intervertebral disk with an elongated slightly ventrally curved recess for receiving the guide pins of the base plate. Figures 2 and 8 show the top of the intervertebral disk with its semi-cylindrical convex designed articulating surface. The articulating surface lies on a partial surface of a cylinder with the radius R.

The intervertebral disk is made of UHMWPE. The cover plate facing side of the intervertebral disk is convex and semi-cylindrical and has a radius of 25 mm. The concave depression or recess of the cover plate with R = 25 mm takes on the convex bulge of the intervertebral disk also R = 25 mm so that a contact surface is formed, which lies on a partial surface of a cylinder. This results in a total contact area of about 650 mm ² . As a result, an areal distribution of load and no punctiform or linear load distribution on the intervertebral disk is achieved.

The entire articulating surface of the concave sink or recess in the cover plate corresponds to the contact surface.

Furthermore, the intervertebral disk on its base plate side facing an elongated slightly curved recess, which is shown in Fig. 3 and 9. This recess is provided for receiving the pins of the base plate. The pins are shown in Figures 4, 5, 8 and 9. The intervertebral disk lies with its longitudinal axis parallel to the lateral axis, so that bending, tilting or rotating movements about the lateral axis in Anteflexions- and Retroflexionsrichtung are possible, but are suppressed in the lateral direction.

Due to the larger diameter of the recess in the intervertebral disk compared to the diameter of the pin of the base plate, the intervertebral disk can perform limited translational movements and minimal rotational movements on the base plate. The rotational movement is physiological to about 1, 5

Limited degrees.

The pins on the base plate have a diameter of 6 mm. The recess in the intervertebral disk has a longitudinal diameter in the lateral direction of 18 mm and in the retroflexion anteflexion direction of 8 mm.

Starting from a central position, the intervertebral disk can move on the base plate in the lateral direction 2 mm or a total of 4 mm from a lateral extreme position to the other. Starting from a central position, the intervertebral disk on the base plate can move 1 mm in the retroflexion direction and 1 mm in the anteflexion direction or a total of 2 mm from the dorsal extreme position to the ventral extreme position.

In a bending movement, the base and cover plates can be inclined up to 20 degrees to each other.

Thus, the embodiment of the invention allows degrees of freedom of movement as in a natural vortex segment, which are avoided even with complex movements through the superimposed cylinder part surfaces of intervertebral disk and cover plate load peaks on the intervertebral disk.

Claims

claims

A vertebral intermediate implant, comprising a base plate, a cover plate and a swirl intermediate disc, wherein the intervertebral disc has the shape of a half-cylinder whose longitudinal axis extends in the lateral direction.

2. intervertebral implant according to claim 1, wherein the intervertebral disc has the shape of a plano-convex half-cylinder.

3. intervertebral implant according to claim 1 or 2, wherein the lateral ends of the intervertebral disk are flat, semi-conical or hemispherical configured.

4. intervertebral implant according to one of claims 1 - 3, wherein the intervertebral disk has a planar articulating surface which is mounted movable in translation on the base plate.

5. intervertebral implant according to claim 4, wherein the intervertebral disc in the planar articulating surface has at least one recess which for receiving at least one on the

Base plate mounted pin or half cylinder is used.

7. intervertebral implant according to one of claims 1-5, wherein the cover plate has a semicylindrical recess corresponding to the receiving part of the semi-cylindrical articulating surface of the intervertebral disk.

8. vertebral intermediate implant according to one of claims 1-7, wherein the semi-cylindrical configured articulating surface of the intervertebral disk and the semi-cylindrical configured articulating

Surface of the cover plate have the same radius.

9. intervertebral implant according to one of claims 1-3, wherein the intervertebral disk has a planar articulating surface, which is mounted in a translational movement on the cover plate in the lateral direction.

10. intervertebral implant according to claim 9, wherein the intervertebral disc in the planar articulating surface at least has a recess which serves to receive at least one mounted on the cover plate pin.

11. vertebral intermediate implant according to one of claims 1 - 3, 9 or 10, wherein the base plate has a corresponding semi-cylindrical recess for receiving the semi-cylindrical articulating articulating surface of the intervertebral disk.

12. Vertebral intermediate implant according to one of claims 1 - 3 or 9 - 11, wherein the semicylindrical designed articulating surface of

Intervertebral disk and the semi-cylindrical designed articulating surface of the base plate have the same radius.

13. intervertebral implant according to one of claims 1 - 3, 7 or 8, wherein the intervertebral disk and the base plate are firmly and immovably connected to each other or the intervertebral disk is incorporated in the base plate.

14. Intervertebral implant according to one of claims 1 - 3, 11 or 12, wherein the intervertebral disk and the cover plate are fixedly and immovably connected to each other or the intervertebral disk is incorporated in the cover plate.

15. vertebral intermediate implant according to one of claims 1-14, wherein the base plate and / or the cover plate made of titanium or a titanium alloy and the intervertebral disk made of polyethylene or titanium or a titanium alloy.

16. Intervertebral implant according to claim 15, wherein the intervertebral disk consists of titanium or a titanium alloy.

17. Use of the intervertebral space implant according to one of claims 1 - 16 for the treatment of scoliosis, herniated disc, kyphosis, discus fracture, black disc, spontaneous deformation, lumbago, spondylosis deformans, widow's hump, spondylomyelitis, osteochondrosis, osteofibrosis,

Spina bifida, lordosis, spondylotosis, Schipper's disease, myelomeningocele, brachialgia, Baastrup's signs, vertebral ankylosis, Scheuermann's disease, cervical syndrome, lendencyphosis, torticollis and Bechterew's disease.