EP1722722A1

EP1722722A1 - Implant used in stabilising operations on the thoracic and lumbar vertebral column

Info

Publication number: EP1722722A1
Application number: EP04718948A
Authority: EP
Inventors: Fritz Magerl; Roger Stadler
Original assignee: Sepitec Foundation
Current assignee: Sepitec Foundation
Priority date: 2004-03-10
Filing date: 2004-03-10
Publication date: 2006-11-22
Also published as: WO2005087143A1; CA2559796A1; JP2007526049A; US20070208343A1

Abstract

The invention relates to an implant used in stabilising operations on the thoracic and lumbar vertebral column for restoring the load-bearing capacity of the vertebral column. According to the invention, the insertion region of said implant (I) comprises a wedge-shaped distraction part (C), which permits the vertebral bodies to be pushed apart in order to increase the intervertebral distance. In addition, guide elements in the form of grooves (7) and/or strips are provided on said wedge-shaped distraction part (C) and/or in the implant part (D).

Description

Applicant: Sepitec Foundation FL-9490 Vaduz (Liechtenstein)

Subject: Implant for stabilization operations on the thoracic and lumbar spine

Description:

The invention relates to an implant for stabilizing operations on the thoracic and lumbar spine to restore the resilience of the vertebral body column.

In a known intervertebral implant DE 200 04 693 U1, the vertical distance of the vertebral bodies can be increased by rotating the implant in the intervertebral disc space. The vertical distance increases by the difference between the implant width and the implant height when the elongated cuboid vertebral implant is inserted with its side walls parallel to the end plates of the vertebral bodies into the intervertebral disc space and then rotated 90 degrees about its longitudinal axis using the insertion instrument attached to the implant. A prerequisite for the distracting effect of the mechanism mentioned is that the implant is taller than it is wide. There is no other way of increasing the vertical distance from this document. The vertebral implant in question has vertical end walls and side walls and a central cut-out in the vertical direction, the end walls being significantly thicker than the side walls in order to enlarge the contact area with the edge strips of the vertebral bodies. In the side view, the upper and lower edges of the side walls are convex all the way to the front end of the implant. Such a shaping of the contact surfaces to the vertebral bodies can also be found in other intervertebral implants and only serves to improve the contact of the side walls and that of the graft material filled into the implant cavity with concave vertebral end plates. The edges of the implant are rounded to reduce the risk of damaging important structures in the vicinity of the implant.

In the case of another known intervertebral implant (WO 01/54 620 A1) which can be produced from different materials and has differently structured contact surfaces with the vertebral bodies, these surfaces can also be inclined differently, as a result of which the implant as a whole can have a more or less pronounced wedge shape. The wedge of the implant obviously does not serve to increase the intervertebral distance, especially since it is mentioned several times that the rear end of the implant lantats should be higher than the front. If one assumes that the end of the implant with which it is inserted into the intervertebral disc space is usually referred to as the front end, the wedge shape appears to have a function other than a distraction. It apparently serves to restore a forward convex curvature of the lumbar spine. If the implant is to distract to any appreciable extent, it would have to have an additional wedge with a greater slope at its front end.

Furthermore, an implant made of human or animal, preserved bone or another biocompatible material, wedge-shaped in side view and ring-shaped, C-shaped or rectangular in top view (WO 00/74 608 A1) has become known. In this case, the selectable wedge only serves to restore the natural curvature of the spine.

The invention has set itself the task of creating pressure-resistant implants that can be inserted optimally and can also cause distraction in the intervertebral disc spaces of the thoracic and lumbar spine from the rear, from the side or from the side, and can also cause distraction and also enable the resilience the vertebral body column can be restored.

This is achieved according to the invention in that the implant part has a wedge-shaped bevel at its insertion area, which enables the vertebral bodies to be pushed apart to enlarge the intervertebral distance.

A particular advantage of the implants according to the invention is that the vertical spacing of the vertebral bodies can be increased with the wedge-shaped insertion part of the implant.

The invention considerably facilitates the surgical technique of the dorsal, dorsolateral or lateral implantation of intervertebral implants and the safety and the success rate of these techniques are improved. Apart from the usual function of an intervertebral implant, the use of the intervertebral implant according to the invention offers the following advantages:

A firm jamming of the implant in the intervertebral disc space is achieved in order to ensure the stability necessary for the bony consolidation of the spinal fusion. The increase in the vertical distance of the vertebral bodies to be stabilized (distraction) is made possible both for the jamming of the implant to achieve the necessary tension in the soft tissues and to achieve the enlargement of the spinal canal and the intervertebral foramina (decompression) associated with distraction.

It is also proposed that the implant be formed from a wedge-shaped insertion part (distraction part C) and a pressure-transmitting implant part (D). At least the final phase of distraction, which is decisive for the jamming of the implant, can be produced with the implant itself. For biomechanical reasons, the longitudinal axis of the implant fully inserted into the disc space can lie in the frontal plane.

It is advantageous if the angle enclosed by the wedge surfaces is at least approximately 30 °, preferably 25 ° to 30 °. This results in good options without damage consequences when inserting the implant.

A particularly advantageous embodiment is that guide elements in the form of channels and / or strips are provided in the wedge-shaped end part and / or in the implant part. In a special embodiment, channels are incorporated into the upper and lower surface of the pressure-transmitting implant part adjacent to the recess on the wedge side, the edges of which are sharp and parallel or concentric to the sharp front edges, the channels or the strips attached to them possibly also running in a straight line , It is also provided in a special embodiment that the channels have the shape of an inverted pent roof-like, two-sided channel, the rear surface of which is perpendicular to the surface of the implant and forms a sharp edge with it, and the front surface of which rises obliquely against the surface of the implant.

Further features of the invention are thus special configurations which automatically guide the implant from the sagittal or oblique insertion direction into the intended frontal end position when it is inserted into the intervertebral disc space. For this purpose, the implant is made rotatable in the intervertebral disc space from the sagittal or oblique implantation direction to the transverse end position. Because the desired firm jamming of the implant restricts or makes it impossible to rotate, the implant is equipped according to the invention with the guide device, which causes the implant to automatically rotate into the transverse end position during insertion into the intervertebral disc space. Nevertheless, if the cross End position is not reached automatically, allowing completion of the rotation. Despite the special design, it is also possible to keep the surface pressure in the area of the contact surfaces between the vertebral bodies and the implant as small as possible and therefore to make the surfaces of the implant as large as possible. The implant can be implanted from behind (PLIF, TLIF), from the side, or with the help of the new technology (EPLIF) explained in more detail from diagonally behind or biportally or uniportally.

Further features are contained in the subclaims and also in the description below. In the following description, exemplary embodiments of the invention are explained in more detail with reference to the drawings. Show it:

Figure 1 shows an embodiment of an intervertebral distraction implant in a view from above.

Figure 2 is a section on the line II-II in Figure 1;

Fig. 3 is a section along the line III-III in Fig. 1;

Fig. 4 is a section along the line IV-IV in Fig. 1;

5 shows a section along the line VN in Fig. 1.

Fig. 6 shows another embodiment of an intervertebral distraction implant

In a top view;

7 shows a section along the line Vll-Vll in Fig. 6.

Fig. 8 is a section along the line VIII-VIII in Fig. 6;

Fig. 9 is a section along the line IX-IX in Fig. 6;

Fig. 10 is a section along the line X-X in Fig. 6;

11 shows a further exemplary embodiment of an intervertebral distraction implant in a view from above;

12 is a rear view;

Figure 13 is a section along the line Xlll-Xlll through a guide trough.

14 shows a view of the embodiment according to FIG. 11 from the side (implant rear end);

15 shows an oblique view of the embodiment according to FIGS. 11 to 14;

16 shows a next exemplary embodiment of an intervertebral distraction implant in a view from above; 17 is a side view of the implant according to FIG. 16 (front end of implant);

18 is a front view;

Fig. 19 is a section along the line XIX-XIX in Fig. 16;

Fig. 20 is a section along the line XX-XX in Fig. 16;

21 is an oblique view of the embodiment according to FIGS. 16 to 20;

22 and 23 show a representation of the vertical expansion of an intervertebral disc space with the implant initially attached (FIG. 22) and with the implant then inserted into the intervertebral disc space (FIG. 23); 24 to 27 show the implantation of an intervertebral distraction implant, the figures showing phases I to IV of the course of an implantation; 28 and 29 a distraction instrument in a view from above and from the front.

For now, some basic information should be given that is important with regard to the present invention:

Spinal fusion is usually a bone connection of vertebrae that permanently blocks the mobility of the connected vertebrae. To create a spondylodesis, new bone-stimulating materials such as bone chips or bone replacement materials are either inserted between the vertebral bodies (interbody spondylodesis) or placed over the posterior vertebral elements (dorsal spondylodesis). The prerequisite for the conversion of these materials into solid bones is that no movements that interfere with the conversion process take place in the relevant section of the spine during new bone formation. To ensure this, stabilizing implants are often used.

Pain that cannot be influenced by conservative treatment measures, spinal cord or nerve root compressions and malpositions are indications for interbody spondylodesis. In principle, pain can come from all pathologically altered structures of the spine. If vertebrae no longer move against each other as a result of such changes, one speaks of an instability. Herniated discs and narrowing of the spinal canal or intervertebral holes are responsible for the development of spinal cord or nerve root compression. Spondylodesis also eliminates the causes of compression syndromes (decompression). Because inter-corporeal spinal fusion always removes intervertebral discs and this massively affects the stability of the spine, their resilience must always be restored. This can e.g. B. happen with flameproof bone blocks that are removed from the patient (autogenous bone blocks) and inserted between the vertebral bodies. However, because the resilience of such chips is often uncertain and their availability is limited, and because the morbidity caused by chip removal can be considerable, bone substitute materials made from extraneous materials are increasingly being used together with intervertebral implants ("cages") instead of autogenous bone blocks.

The spondylode technique has to meet the following requirements in particular: Reduced distances between the vertebral bodies, caused by narrowing of the intervertebral discs, must be normalized and vertebral displacements and bends in the spine must be eliminated. Since increasing the vertical vertebral body distance by "distraction" has a strong decompressing effect, distraction is usually an essential part of the procedure. With each distraction acting in the area of the vertebral body, an existing kyphotic kink of the relevant section of the spine is also reduced or it is prevented that a kink occurs as part of the spinal fusion. This effect can be supported by a slightly wedge-shaped shape of the interverebral implant in the sagittal direction. Distraction is achieved in the conventional way with the help of special instruments, with pedicle systems or by turning special intervertebral implants in the intervertebral disc space by 90 degrees.

Implantation techniques for intervertebral implants are used as follows:

Intervertebral implants can be inserted from the front in all areas of the spine (ALIF - anterior lumbar interbody fusion); on the lumbar spine also from behind (PLIF - posterior lumbar interbody fusion), TLIF - transforaminal lumbar interbody fusion), from the side or from the back. One or two implants are used per intervertebral disc space. If two implants are inserted from behind through two separate openings in the intervertebral disc ring, one speaks of a biportal implantation. With a uniportal implantation (see Ab.) The intervertebral disc is only opened at one point.

When we talk about intervertebral implants in the following, we mean pressure-resistant, non-elastic implants. A pressure-resistant intervertebral implant functions as a placeholder, which transfers loads from the upper to the lower vertebra, secures the vertical distance between the vertebral bodies and ensures that a solid bone bridge can form between the vertebral bodies. Bone or bone substitute material filled into the implants and / or deposited around them, or the blood that accumulates in the intervertebral disc space alone, forms the matrix for new bone formation. The stability of the sponylodesis plays a crucial role in the ossification process because movements between the intervertebral implant and the vertebral bodies can prevent the bony consolidation of the interbody spondylodesis. In addition, the intervertebral implant can sink or collapse into the vertebral body. To prevent this, spinal fusion is usually stabilized by implants anchored ventrally or dorsally to the vertebrae.

In addition to the therapeutic, the distraction is also of considerable mechanical importance: the distension of the intervertebral ligaments and the intervertebral discs that accompanies the distraction generates a counterforce that clamps the intervertebral implant between the vertebral bodies. This clamping force also prevents harmful movements between the vertebral bodies and the implant and also reduces the risk of secondary implant dislocation, which can have serious consequences.

When implanting intervertebral implants, distraction is usually achieved with the help of special devices (e.g. distraction instruments, pedicle system) or by using an intervertebral implant whose height of the vertical side walls is greater than the width of the horizontal top and bottom surfaces. in such a way that the walls first lie against the end plates of the vertebral bodies. If you then turn the implant 90 degrees around its longitudinal axis, the intervertebral disc space is expanded by the difference between the height and the width. Because the width has to be smaller than the height, this technique has the disadvantage that the sizes of the surfaces transmitting the axial pressure of the spine from the vertebral bodies to the intervertebral implant must be relatively small. With small contact areas, however, there is a risk that the intervertebral implant will break into the vertebral body due to excessive surface pressure.

For the time being, an overview of the various construction features is to be given, which will then be discussed in detail at the end of the description of the drawing figures. The implant body I is, overall, preferably kidney-shaped or bean-shaped. Its longitudinal diameter is larger than its transverse diameter. The front implant wall 10a is convexly curved in the longitudinal direction of the implant. The implant rear wall 10b can be straight or concave in this direction. At the distraction wedge C and at the opposite end of the implant, the front and rear walls merge into one another as seen in the top view, so that the relevant ends of the implant are rounded in the top view. In the direction from top to bottom, the front 10a and rear implant wall 10b are vertical to a horizontal plane bisecting the implant. The implant I can have a central recess 6 from its surface 2a to the lower surface 2b or can be full (not shown). A special feature of the distraction implants according to the invention, which can be shaped differently in details, are various guide elements such as channels 7, sharp-edged strips 9 attached to them, specially designed implant edges 3a, 3b, 4 and sharp-edged strips 15 attached to the front edges of the implant.

From a functional point of view, the implant consists of two parts: the distraction wedge C and the pressure-resistant implant part D, which transmits the pressure from one vertebral body to the other.

With the distraction wedge C, the intervertebral disc space is expanded vertically when the implant is inserted. This part of the implant is wedge-shaped in elevation. The base 1a of the wedge connects the distraction wedge C to the implant part D and has the same height as the implant part D. The surface of the base 1a can be perpendicular (Fig. 1, 6, 11,) or oblique (Fig. 16 ). The height difference between the wedge base 1a and the front wedge end 1d is preferably approximately 3 mm. The implant then increases the height of the intervertebral disc space by 3 mm. The wedge surfaces 1b, 1c, which are flat in addition to the special guide elements 7, 7a-b, 8,9, are inclined in relation to the wedge end 1d, which is vertical in elevation and rounded in plan, such that the wedge end is lower than the wedge base. The angle α (FIGS. 3, 8, 12, 20) enclosed by the wedge surfaces 1b, 1c is preferably between 25 ° and 30 °. At the wedge base 1a, the wedge surfaces 1b, 1c of the distraction wedge C go with a slight rounding 14 (only shown in FIGS. 16 and 21) and steplessly into the upper or Lower surface 2a, 2b of the pressure-absorbing implant part D above. Both wedge surfaces 1b, 1c can each one of the sharp front edges 3, 3b Wedge end 12 of the implant part D have parallel or concentric guide trough 7, which continue into the guide troughs 7 respectively attached to the upper and lower surface of the wedge-side part of the implant part D. Also straight channels are conceivable, which run through the surfaces of the implant in such a way that their direction corresponds approximately to a tang, which is applied to the curvature of the front wall 10a there at the transition of the implant part D into the distraction wedge C. In the side view, the tangent runs parallel to the longitudinal axis of the implant. The channels are preferably in the middle of the surfaces 1b, 1c (FIGS. 1, 6, 11), but can also be attached further back (FIG. 16).

The parts of the guide channels 7 or strips 9 attached to the distraction wedge C form guide elements and can have different shapes: a) In cross section, the channel 7 has the shape of an inverted pitched roof with two surfaces. The vertical rear wall 7b of the channel forms a sharp edge 8 with the rear portions of the wedge surfaces 1b, 1c. The front channel surface 7a forms an acute angle with the channel rear wall 7b at the channel depth and rises from the depth obliquely towards the front portions of the wedge surfaces 1 b, 1c. The gutter can be the same width and depth everywhere. At the wedge base 1a, it merges into the groove of the implant part D. This channel then has a kink in its longitudinal course at the transition from the distraction wedge C into the implant part D, which corresponds in each case to the bending of the wedge surface 1 b or 1 c in question against the upper or lower surface of the implant part D. b) The groove 7b attached to the distraction wedge C can also be designed in such a way that the groove gradually widens from the wedge base 1a towards the wedge end 1d (FIG. 1). In this case, the front channel surface 7b has a lower inclination towards the respective surface 1b or 1c of the wedge end C than the corresponding channel surfaces of the implant part D. The height of the vertical channel rear wall 7b and thus also the channel depth can remain unchanged. c) As an additional guide element on the distraction wedge C, a pent roof-shaped bar 9 (FIGS. 6, 7) can be attached in such a way that its vertical front wall continues the vertical rear wall 7b of the guide trough 7. The rear wall of the ledge falls obliquely against the respective surface 1b or 1c of the distraction wedge C. In this embodiment, the bar has a sharp upper edge 9. The bar can begin at the wedge end 1d and end at the wedge base by continuously decreasing its height from the wedge end 1d to the wedge base 1a such that it no longer projects beyond the implant part D on the wedge base 1a , The bar can also be in the same pent roof shape, which it has in the distraction part C. Continue implant part D. In this case, the bar then projects beyond the surfaces 2a, 2b of the implant part D.

The edges formed by the wedge surfaces 1b, 1c and the vertical walls 2a, 2b, 1d connecting them vertically can be rounded in the front half of the distraction wedge C or be sharp like the front front edges 3a of the implant part D and are in the rear part of the distraction wedge C. the relevant edges rounded.

The top view of the implant part D is bean or kidney-shaped and can have a central recess 6, which penetrates the implant in the vertical direction, for receiving bone or bone substitute material, or can be compact and have a device for fastening an implantation instrument (5).

Upper and lower surfaces 2a, 2b of the implant part D run parallel to one another in the longitudinal direction of the implant. They can be flat or convex in this direction and can be flat or slightly convex in the direction from the back to the front, and can be parallel or inclined to each other. The front implant wall 10a is convexly curved in the longitudinal direction of the implant. The implant rear wall 10b can be straight or concave in this direction. In the direction from top to bottom, the vertical implant walls 10 can be flat, convex or concave and closed, or they can have openings that penetrate from the outside into the central recess. The front edges of the implant part D become sharp 3a, 3b towards the wedge end 12 and increasingly round towards the opposite end 13. At the wedge end 12 of the implant part D slightly sharp-edged guide strips 15 protruding from the edges of the front wall 3a can be attached (FIGS. 16-21). A screw or plug device 5 for fastening an insertion instrument can be attached to the implant part 13 lying opposite the wedge end. At the wedge end 12 of the implant part D can in the upper u. Lower surface 2a, 2b of implant part D each have a pent roof-shaped channel 7 in cross section (FIG. 11), which continues the corresponding channel of distraction wedge C into implant part D. In addition to the widening in the distraction wedge C towards the end of the wedge (FIG. 1), the channels can be shaped like the channels in the distraction wedge C. The sharp edges 8 of the grooves run parallel to the sharp front edges 3a. However, their curvature can also correspond to an arc concentric with the sharp front edges 3a. Also straight channels are conceivable (not shown), which diagonally through the Surfaces 2a, 2b of the implant run. Their direction should correspond to that of a tangent which, in the view from the transition of the implant part D into the distraction wedge C, is applied to the curvature of the front wall 10a there. In the side view, the tangent runs parallel to the longitudinal axis of the implant.

Another possible form of the guide elements is that not only does the channel 7 continue from the distraction wedge C into the implant part D but also a sharp-edged bar 9 attached to the channel. This bar 9 then projects significantly beyond the surfaces 2a, 2b of the implant part D. For the success of the distraction caused by the intervertebral implant itself, the shape of the distraction wedge C.

According to the invention, the distraction generated by the intervertebral implant itself is achieved in that the distraction wedge C, that is to say the part of the implant with which it is introduced into the intervertebral disc space, is wedge-shaped. The distraction wedge C of the intervertebral implant expands the intervertebral disc space by the difference between the wedge base 1a and the wedge end 1d, e.g. B. by 3mm. It is essential for the success of the distraction that the surfaces 1a, 1b forming the wedge, apart from the guide elements attached there, are flat and that the angle oc enclosed by the wedge surfaces 1a, 1b (FIGS. 3, 8, 12, 20 ) is not too big. It should preferably not be greater than about 30 degrees. At a larger angle there would be a risk that the edges of the vertebral bodies would collapse when the distraction wedge C was inserted. A convex bending of one or both wedge surfaces or a completely spherical shape of the insertion part would also be unfavorable, as is the case with some known intervertebral implants. If an implant with a convex or spherical insertion part is pressed into an intervertebral disc space and this is a few millimeters lower than the implant height, the insertion part first hits the edges of the vertebral body with a steep incline. These edges can break in if, as is the case with the intervertebral according to the invention, the implant has to be pressed or hammered into the band cavity space against considerable resistance (see FIG. 22). It is therefore not safe to use an intervertebral implant designed in this way as a true distraction implant in the sense of the invention under discussion here. In the case of diseases of intervertebral discs, the present height as well as the vertical expandability (distractibility) of the intervertebral disc space can vary widely. The height of the intervertebral disc space that can be achieved by distraction is decisive for the height of the intervertebral implant to be implanted. The intervertebral implant must be adaptable to this height. To make this possible, the intervertebral implant according to the invention is provided at different heights. The height differences between the individual implants and the shape of the distraction wedges can increase linearly (e.g. by 3 mm each) or non-linearly from the minimum to the maximum height.

The distractibility of the intervertebral disc space can already be recognized from the mobility of the vertebrae that delimit the intervertebral disc space when the intervertebral implant is always removed for implantation of the intervertebral implant. The two vertebrae can still be connected so tightly that very strong resistance has to be overcome when trying to distract. However, it can also be the case that a considerably vertical expandability of the intervertebral disc space becomes apparent during the distraction attempt.

With a tight connection of the vertebrae, the distractibility of the intervertebral disc space is low. In this case, only the implant is used for distraction. The implant is selected, the wedge end 1d of which can just be inserted into the intervertebral disc space. The distraction obtained when the implant is hammered into the intervertebral disc space is then sufficient for its stable jamming.

In order to avoid that an already inserted implant has to be removed and replaced by a higher one, the disc space is distracted gradually with the help of special distractors (Fig. 28 and 29) until it can be recognized by the resistance that arises. that the limit of distractibility has almost been reached. Then the implant is inserted, the wedge end (1d) of which can just be inserted into the intervertebral disc space. The last stage of distraction, which ensures a stable jamming of the implant between the vertebral bodies, is again with the interverebral implant itself.

The goal of stable interlocking of the intervertebral implant can only be achieved if the ligaments of the spine and outer parts of the intervertebral disc are tense but not torn. This requires a distraction that can be metered and controlled. A set of special distractors (Fig. 28 and 29) is provided for this purpose, with which the intervertebral disc space can be gradually expanded (distracted) in the vertical direction. From a functional point of view, the bodies of the distractors 16 can consist of two parts, the distracting part being shaped similarly to the intervertebral implant according to the invention and in particular also having a distraction wedge 17. The heights 19 of the distractors are matched to the interveretebral implants such that each distractor enables the distraction wedge C of the matching intervertebral implant to be inserted into the intervertebral disc space. According to the invention this is achieved in that the wedge base 1a and body 16 of the distractor each slightly, for. B. 1 mm, is higher than the wedge end 1d of the matching intervertebral implant. The distractor also has a handle 18 connected to the distracting part for inserting and hammering the distractor into the intervertebral disc space. Each distractor can have a handle that is firmly attached to its body or by a plug or screw connection.

In the direction of its longitudinal axis, the intervertebral implant according to the invention can be inserted into the intervertebral disc space from obliquely behind ("dorsolateral") (see FIGS. 24 to 27), sagittally from behind ("dorsal", PLIF or TLIF) or from the side. In the end position in the intervertebral disc space, the longitudinal axis of the implant must run in the transverse direction, i. H. lie in the frontal plane. Except in the case of a purely lateral implantation direction, the implant must therefore be rotated from the dorsolateral or dorsal to the transverse end position during insertion into the intervertebral disc space so that its longitudinal axis ultimately lies in the frontal plane. With the desired stable jamming of the implant, however, its rotation in the intervertebral disc space can be considerably difficult or impossible, unless special precautions are taken to enable the rotation.

The invention is intended to facilitate the insertion of the intervertebral implant into the transverse end position. This is achieved according to the invention by equipping the intervertebral implant with special guide elements which rotate the implant into the end position when it is inserted.

The guide elements on the distraction wedge C consist of the channels 7 and any strips 9 and on the implant part D of the sharp edges 3a, 3b, the channels 7, the possibly attached strips 9 and the possibly attached strips 15 on the sharp leading edges 3a. Since the front wall 2a of the implant represents the sector of a round cylinder, the axis of which is close to the center of the spinal canal, the leading edges 3a, 3b of the implant are the sector of a circular arc bent accordingly. The curvature of the channels 7 and the strips 9 possibly attached to them corresponds to an arc concentric with the front edges.

The back pressure that occurs during distraction presses the end plates of the vertebral bodies against the intervertebral implant. When inserting the implant, the guide elements therefore cut into the end plates of the vertebral bodies. The curvature of the edges causes the implant to automatically rotate along an arc towards the end position during insertion into the intervertebral disc space.

By a fixed at its rear end 13 z. B. rod-shaped insertion instrument El, the implant is initially additionally steerable. The instrument is removed as soon as it has reached the limit of the insertion opening in the intervertebral disc ring and can therefore no longer be pivoted. The implant is then hammered in further by a plunger ES attached to its rear end 13 and, if necessary, rotated simultaneously with the plunger into the final position.

This final rotation into the transverse position is possible because the guide elements are only attached to the insertion part of the intervertebral implant and the front edges of the implant become rounded towards the other rear end of the implant. When hammering is no longer carried out in the direction of the longitudinal axis of the implant, but rather obliquely thereto (FIGS. 26, 27), the part of the implant carrying the guide elements still penetrates along the circular arc in the direction predetermined by the guide elements, the rear end of the implant 13 can be pushed out of the circular path to the front thanks to the rounded front edges 4 and missing guide elements. It swivels forward about a vertical axis in the area of the insertion part.

If the intervertebral implant is inserted into the intervertebral disc space from the side, it does not have to be rotated. In this case its longitudinal diameter is riding when inserting in the frontal plane. Intervertebral distraction implants (not shown) designed for lateral use therefore do not necessarily have to be equipped with guide elements.

In order to reduce the pressure acting on the contact surfaces of the implant with the vertebral bodies, the intention of the invention is also to introduce the largest possible implant into the intervertebral disc space. Because using the usual access routes through the spinal canal from the dorsal (PLIF, TLIF) the access to the intervertebral disc can be very narrow, an access (Fig. 24 to 27) is recommended through which implants with larger transverse diameters can be inserted. The new approach, which has already been announced, leads to the outside of the intervertebral foramen under the mass of the muscles of the back (Fig. 24 to 27). From there, the intervertebral disc ring is opened ventrally from the arch roots (extraforaminal submuscular access). The opening can be expanded in such a way that implants with a larger transverse diameter can be inserted than when accessing through the spinal canal. The implant with the greatest possible width should always be inserted.

Intervertebral distraction implants should be insertable in all areas of the thoracic and lumbar spine from the dorsal, dorsolateral or from the side into the intervertebral disc space. It is therefore intended to adapt the shape of the implant parts both to the respective anatomical conditions and the intended implantation technique by z. B. for purely lateral or purely dorsal implantations, among other things, the curvature of the guide elements can be adapted. Different size ratios both in the individual areas of the spine and in the accesses to the intervertebral discs also mean that the intervertebral implants adapted to the application site and the application technology must also be provided in different sizes.

Intervertebral distraction implants can be made of metal, polymer or composite. Intervertebral implants made of polymer or composite are not visible radiologically. In order to make them visible, radiological shading elements are incorporated into the implants. It is envisaged to equip the implant according to the invention with radiologically shading elements, e.g. B. with very thin tantalum wires. The surfaces of the implants can be structured and / or coated. projecting structures are attached in such a way that they preferably form rows running parallel or concentrically to the front edges of the implant in order to be able to also act as guide elements.

The following is detailed about the drawing figures:

1 to 5 show an exemplary embodiment of an intervertebral distraction implant with guide channels that become wider towards the front. 1 is a top view of the implant. The implant I consists of a pressure-receiving part D and the distraction wedge C. In supervision, it has a convex front wall 10a, a straight rear wall 10b and is rounded off on the diatraction wedge C and the opposite end 13. The implant walls enclose a central recess 6. The front edges of the implant part D become increasingly sharp 3a, 3b towards the distraction wedge C and are increasingly rounded toward the opposite end 13. 4. At this end of the implant part D there is a bore 5 for the attachment of an insertion instrument. In the upper 1 b and lower surface 1 c of the distraction wedge C and in the adjacent surfaces 2 a, 2 b of the implant part D, grooves 7 running parallel or concentric to the front front edges 3 a are incorporated. In this exemplary embodiment, the channels provided in the middle portions of the wedge surfaces 1b, 1c and the adjacent surfaces 2a, 2b of the implant part D become wider towards the wedge end 1d.

The trough 7 can be seen in particular from FIG. 2. In cross section, it has the shape of an inverted pent roof and accordingly a vertical rear wall 7b and a front surface 7a rising obliquely against the surfaces 1b, 1c of the distraction wedge C. The rear wall 7b of the channel forms a sharp edge 8 with the surface of the distraction wedge C. The front wall 10a and the rear wall 10b of the distraction wedge C are perpendicular and at a right angle to the surfaces 1b, 1c.

Fig. 3 shows a longitudinal section through the distraction wedge. The upper wedge surface 1b and the lower wedge surface 1c enclose the angle oc, which should not be greater than 30 degrees. The surfaces 1b, 1c forming the wedge go over at the wedge base 1a with a kink into the surfaces 2a, 2b of the part 12 of the implant part D adjoining the distraction wedge. The transition in question can be made by a small radius 14 may be rounded off (not shown here, see FIGS. 16, 20, 21). The surface opposite the wedge end 1d delimits the central recess 6.

4 shows in a section, in particular, the front edges 3a, 3b which have become sharp at the wedge end 12 of the implant part D. They are formed by the surfaces 2a, 2b and the front surfaces of the front wall 2a and rear wall 2b of the implant part D. Front 2a and rear wall 2b enclose the central recess 6 which penetrates the implant from top to bottom.

The section according to FIG. 5 shows the front edges 4 which become increasingly round towards the implant end 13 opposite the distraction wedge C. Otherwise, the section is to be described in the same way as the section shown in FIG. 4.

The exemplary embodiment shown in FIGS. 6 to 10 shows an intervertebral distraction implant with guide strips attached to the guide channels. In the view according to FIG. 6 it can be seen that the implant I consists of a pressure-absorbing part D and the distraction wedge C. When viewed from above, it has a convex front wall 10a, a straight rear wall 10b and is rounded at the distraction wedge C and the opposite end 13. The implant walls enclose a central recess 6. The front edges of the implant part D become increasingly sharp 3a, 3b towards the distraction wedge C and are increasingly rounded towards the opposite end 13. 4. At this end 13 of the implant part D there is a bore 5 for the attachment of an insertion instrument. In the upper surface 1b and lower surface 1c of the distraction wedge C and in the adjacent surfaces 2a, 2b of the implant part D, grooves 7 running parallel or concentrically to the front front edges 3a are incorporated. In this embodiment, the channels become shallower towards the wedge end 1d. As a further guide element, cross-section-shaped strips 9 are attached here, which do not protrude from the wedge surfaces 1b, 1c higher than the level of the surfaces 2a, 2b of the implant part D, begin at the wedge end 1d and become lower against the wedge base 1a, that they no longer protrude beyond the surfaces 2a, 2b of the implant part D adjoining the distraction wedge C. The strips continue the direction of the channels to the end of the wedge 1d. In this case, the groove 7 and strips 9 are also located in the middle portions of the wedge surfaces 1b, 1c and the adjacent surfaces 2a, 2b of the implant part D.

7 illustrates the shape of the channels 7 and the pent roof-shaped, sharp-edged strips 9). Each channel has the shape again in cross section an inverted pent roof and correspondingly a vertical rear wall 7b and a front surface 7a rising obliquely against the surfaces 1b, 1c of the distraction wedge C. However, the rear wall 7b of the channel continues in the front wall of the strip in such a way that both walls form a flat surface that is perpendicular to the wedge surfaces 1b, 1c. This surface forms, with the surface sloping obliquely against the respective surface 1 b or 1 c of the distraction wedge C, a sharp edge directed towards the front. The front wall 10a and rear wall 10b of the distraction wedge C are perpendicular and at a right angle to the surfaces 1b, 1c.

8 shows a longitudinal section through the distraction wedge. The upper wedge surface 1b and the lower wedge surface 1c enclose the angle oc, which should not be greater than 30 degrees. The surfaces 1b, 1c forming the wedge pass at the wedge base 1a into the surfaces 2a, 2b of the part 12 of the implant part D adjacent to the distraction wedge. The transition in question can be rounded off by a small radius 14 (not here shown, see Fig. 16, 20, 21). The surface opposite the wedge end 1d delimits the central recess 6.

The section according to FIG. 9 shows above all the front edges 3a, 3b which have become sharp at the wedge end 12 of the implant part D. They are formed by the surfaces 2a, 2b and the front surfaces of the front wall 2a and rear wall 2b of the implant part D. Front 2a and rear wall 2b enclose the central recess 6 which penetrates the implant from top to bottom. FIG. 10 shows in section the front edges 4 which become increasingly round towards the implant end 13 opposite the distraction wedge C. Otherwise, the section is to be described in the same way as the section shown in FIG. 4.

FIGS. 11 to 14 show an exemplary embodiment of an intervertebral distraction implant with guide channels offset to the rear. The implant I consists of a pressure-absorbing part D and the distraction wedge C. When viewed from above, it has a convex front wall 10a, a straight rear wall 10b and is rounded off at the diatraction wedge C and the opposite end 13. The implant walls enclose a central recess 6. The front edges of the implant part D become increasingly sharp towards the distraction wedge C (FIGS. 3a, 3b) and are increasingly rounded towards the opposite end 13. At this end 13 of the implant part D there is a bore 5 for the attachment of an insertion instrument. In the upper surface 1b and lower surface 1c of the distraction wedge C and in the adjacent surfaces 2a, 2b of the implant part D are parallel or concentrated channels 7 running trically to the front leading edges 3a are incorporated. In this exemplary embodiment, each of the two channels is offset to the rear in such a way that the front surface of the rear wall of the implant part D 10b merges into the rear wall 7b of the channel with a kink or a bend, but continuously, and also the sharp channel edge 8 such a continuation of the sharp one Front edge 3b of the rear wall of the implant part D 10b forms. The rear wall of the gutter shown here has another straight line in the supervision. Their direction corresponds approximately to a horizontally lying tangent, which is placed on the curvature of the front wall 10a there at the transition of the implant part D into the distraction wedge C.

The view according to FIG. 12 shows this intervertebral distraction implant from behind. The upper 2a and lower 2b implant surfaces run parallel to each other and are flat in this case. The wedge surfaces 1b, 1c enclose the angle oc. The front ends of the channels 7 can be seen on the wedge surfaces 1b, 1c. In the section shown in FIG. 13 through the portion of the guide channel 7 located in the implant part D, each of the two channels again has the shape of an inverted pent roof with a vertical rear wall 7b which, with the surface 2a and 2b of the implant part D, has a sharp, forward-facing shape Edge 8 forms and the forward from the depth of the groove obliquely against the surfaces 2a, 2b, respectively. 1b, 1c rises. The view according to FIG. 14 shows the end 13 of this intervertebral distraction implant lying opposite the distraction wedge C. In this case, both the top 2a and bottom surface and the front 10a and rear wall 10b of the implant part D are flat and form right angles with one another. A device for fastening an insertion instrument is attached to this implant part 13. 15 shows the intervertebral distraction implant in a three-dimensional oblique view.

16 to 21 show an embodiment for an intervertebral distraction implant with angled distraction wedge C and guide strips attached to the sharp leading edges. The implant I consists of a pressure-absorbing part D and the distraction wedge C. In this case, the distraction wedge C is attached obliquely to the longitudinal axis (not shown) of the implant running parallel to the rear surface of the implant rear wall 2b in such a way that the base of the distraction wedge C is aligned with the longitudinal axis of the implant includes a forward open angle of approximately 110 degrees. When viewed from above, the implant again has a convex front wall 10a, a straight rear wall 10b and is rounded off at the diatraction wedge C and the opposite end 13. The device for attaching an insertion instrument is attached to this end. The implant walls include one central recess 6 a. In this case, on the part adjoining the distraction wedge C there is in each case a sharp-edged guide bar 15 which emerges continuously from the front surface 10a and protrudes from the upper 2a and lower surface 2b of the implant. These strips 15 replace the sharp front edges 3a present in other designs. In this embodiment, only the wedge-side portions of the front edges of the rear wall have a sharp edge 3b. Against the end 13 of the implant lying opposite the wedge part C, the front edges 4 of the walls of the implant part D become round again in this case. With regard to the location and shape of the guide channels 7, reference is made to FIGS. 11 to 15 and their description.

The profile view of the distraction wedge C according to FIG. 17 is intended to illustrate the sharp-edged guide strips 15 emerging from the front wall 10a of the implant part D. 18 shows a front view of the implant. Representation of the guide strips 15 and their relationship to the front wall 10a and the surfaces 2a, 2b and edges 4 of the implant. The guide strips 15 begin at the transition of the distraction wedge C into the implant part D and do not extend from there more than 10 mm in the direction toward the implant end 13 opposite the wedge end.

The cross section according to FIG. 19 shows the wedge-side portion 12 of the implant part D, how the sharp guide strips 15 protrude beyond the implant part D and emerge continuously from the front wall 10a of this implant part. The front surfaces of the cross-section-shaped guide strips 15 form a continuation of the implant front wall 10a. These front surfaces each form a sharp edge with the surfaces sloping backwards towards the surfaces 2a, 2b of the implant. Each of the two guide strips should not project beyond the implant part D by more than 0.8 mm. Also shown are the guide channels 7 with their vertical rear walls 7b, the front surfaces 7a rising obliquely to the front and the sharp edges 8 formed by the rear walls 7b with the respective surface of the implant part D 2a, 2b. The perpendicular to the base 1a of the distraction wedge C and the 20 illustrates again the distraction wedge C, which has already been described several times. It consists of a base 1a, the two wedge surfaces 1b, 1c and the wedge end 1d. The wedge base 1a passes without interruption into the adjacent part 12 of the implant part D, which in turn forms the wedge-side wall of the central recess 6 there. The two wedge surfaces 1b, 1c are inclined at an angle to one another and pass at the wedge base with a kink into the adjacent surfaces 2a, 2b of the wedge-side portion 12 of the implant part D. The transition in question can have a small radius 14 (see Fig. 16). The three-dimensional image according to FIG. 21 shows the shape of the intervertebral implant 1 according to the invention.

22 and 23 illustrate a schematic representation of the distraction mechanism, how the vertical spacing of the vertebral bodies can be expanded (distracted) with the aid of an intervertebral distraction simplification according to the invention. 22, the implant is placed. In the illustrated case, the intervertebral disc space BR is opened from the dorsal or dorsolateral through the annulus fibrosus AF, so that the intended implant can be inserted through the opening. The intervertebral disc space is completely cleared apart from the annulus fibrosus. The implant is selected whose front wedge end 1d is approximately 1 mm lower than the vertical distance of the vertebral bodies, which runs from top to bottom and is defined by the facing end plates of the vertebral bodies, and can thus just be inserted into the intervertebral disc space BR. 23, the implant is inserted into the intervertebral disc space. With the aid of the insertion instrument El attached to the implant, the implant is inserted into the intervertebral disc space. As soon as the distraction wedge C of the implant has completely penetrated the intervertebral disc space, as shown here, the vertical distance of the vertebral bodies is increased in the direction of the two arrows to the implant height, i. H. distracted. Because the ligaments that connect the vertebrae and the annulus fibrosus are stretched during the distraction, the resistance to be overcome when inserting the implant can become so great, especially in the end phase of the distraction, that the implant can no longer be inserted manually. It must be hammered into the intervertebral disc space by dosing hammer blows on the handle of the insertion instrument (El). In the sense of the invention, it is desirable that the implant is firmly clamped between the vertebral bodies by the tension of the ligaments mentioned and the annulus fibrosus.

24 to 27 show the implantation of an intervertebral distraction implant, with the upper vertebra removed in each of the figures. The lower vertebra W can be seen from above. The intervertebral foramina are located between the articular processes GF and the posterior part of the annulus fibrosus AF. From the outside of the intervertebral foramen, the intervertebral disc is only opened to such an extent that the implant I can be inserted into the intervertebral disc space from the back through the opening and the intervertebral disc space BR can be completely cleared out through the same opening except for the annulus fibrosus AF. In phase I according to FIG. 24, the implant I attached to the insertion instrument E1 is already in the intervertebral disc with the distraction wedge C in the direction of the longitudinal implant IA. BR has penetrated so far that the distraction is complete. In this phase, the implant I is already jammed in the intervertebral disc space. From this phase onwards, the implant must therefore be directed against the end position shown in FIG. 27 by the guide elements attached to the implant. As can be seen from the figure, the insertion instrument El is attached to the implant I in such a way that its shaft encloses an angle of 25 degrees to 30 degrees with the longitudinal axis of the implant. This makes it possible to additionally pivot the implant I somewhat in the direction (small arrow) of the end position with the aid of the insertion instrument El, the shaft of which initially lies almost against the articular process GF. ER denotes the implantation direction specified by the insertion instrument El. In phase II shown in FIG. 25, the implant is inserted further into the intervertebral disc space with the aid of the insertion instrument E1. Thanks to the guide elements in the intervertebral disc space BR, the implant I has turned further towards the end position. The shaft of the insertion instrument El is pivoted so far towards the side that it has reached the lateral limit of access to the spine (not shown) and must therefore be removed.

In phase III (FIG. 26), after removal of the insertion instrument E1, the implant is hammered further into the intervertebral disc space BR with the aid of an impact ram ES located at its end opposite the distraction wedge C. Because of the lateral limitation of access to the spine, the insertion or insertion direction ER cannot be swung out further to the side with the impact tappet. However, the end of the impact ram ES adjacent to the implant I is shaped in such a way that it does not hinder the further rotation of the implant caused by the guide elements attached to the implant. Phase IV is shown in FIG. The implant I hammered in with the impact ram ES has turned into its final position thanks to the guide elements during further impact. The longitudinal axis of the implant IA is now in the frontal plane. The impact ram is removed and the spinal fusion is completed by adding autologous or bone substitute material into the space between the implant I and in addition to the autologous cancellous bone filled into the central recess 6 of the implant or the bone substitute material filled into the recess 6 the posterior portion of the annulus fibrosus AF.

28 and 29 show a distraction instrument. These instruments are used for the preparatory distraction which may be necessary for introducing the intertractable distraction implants according to the invention into the intervertebral space. The instruments consist of a compact body 16, a shaft 20 and a handle 18. The shaft 20 can be fixedly connected to the body 16 or be removable therefrom. The body 16 has a shape similar to the intervertebral distraction simplicity. Its front part 17 is shaped like the distraction wedge C of an intervertebral distraction implant. The surfaces of the body 16 are smooth. Distraction instruments with different body heights 19 are provided. The gradation of the body heights 19 should preferably be 3 mm and be dimensioned such that the body 18 of a distraction instrument is 1 mm higher than the front end 1d of the distraction wedge C of a matching intervertebral distraction implant. This ensures that the distraction wedge C of the corresponding intervertebral implant can still be inserted into the intervertebral disc space as shown in FIG. 22. If it is provided that the shaft 20 can be removed from the body 16 in each case, it is sufficient to provide only a series of bodies 16 with different heights instead of a series of distraction instruments. The axis of the shaft 20 encloses an angle of 25 degrees to 30 degrees with the longitudinal axis of the body 16 which runs parallel to the straight rear wall of the body 16.

There are a number of special features according to the invention, which should be clearly listed again here:

The intervertebral distraction implants created by the invention serve to stabilize interbody spondylodesis. They transfer the forces acting on the upper vertebra to the lower vertebrae and ensure that there are no movements between the two vertebrae and the implant that could interfere with the formation of a solid osseous connection between the two vertebrae.

Such implants can serve as a cage for bone graft material or bone replacement material if they have a recess 6 which extends from cranial to caudal. But they can also be compact, i. H. have no recess. In this case, the materials that promote the bony development of the spinal fusion are deposited around the implant.

Intervertebral distraction implants according to the invention, adapted to the anatomical conditions and the application technique, can be inserted from the dorsal, dorsolateral or from the side into the intervertebral disc spaces of the thoracic and lumbar spine. With the dimensioning and shaping of the implants according to the invention, the intention is to be able to insert the largest possible implants with in particular large contact surfaces to the vertebral bodies in the intervertebral disc space, so that the surface pressure in the areas of the contact surfaces of the vertebral bodies is reduced and there is therefore less risk that the Break in the vertebrae there. In addition, the central recess receiving the bone or bone replacement material should also be as large as possible.

The purpose of the special design of the intervertebral distraction implants according to the invention is also to be able to produce the enlargement of the vertical spacing of the two vertebral bodies (distraction) which is advantageous for spondylodesis in two respects alone with the implant itself. Distraction firstly tensions the ligaments connecting the two vertebrae and the intervertebral disc ring. This causes the fixed jamming of the implant between the two vertebrae, which is decisive for the stability of the spinal fusion. Secondly, the distraction causes an expansion of the spinal canal and the intervertebral foramina and thus a decompression of the nerve tracts passing through the spinal canal and the foramina.

From a functional point of view, the intervertebral distraction implants according to the invention accordingly consist of two parts, a wedge-shaped insertion part (distraction wedge C) and a pressure-transmitting implant part D.

With the distraction wedge C, the vertical distance of the vertebral bodies is increased by an amount corresponding to the difference between the wedge end and the wedge base when the implant is inserted into the intervertebral disc space. The angle enclosed by the wedge surfaces should not be significantly greater than 30 degrees so that the edges of the vertebral bodies do not collapse when the wedge is inserted.

Special distractors (Fig. 28 and 29) can be used to prepare the optimal distraction.

The cylindrical or prismatic shaped pressure-transmitting implant part D can have an opening 6 which is continuous in the vertical direction and serves to receive bone or bone substitute material. But it can also be compact. His Lateral walls can be closed or have openings that extend from the outside inwards. The surfaces facing the vertebral bodies can be flat or curved and parallel or inclined to one another. A device for fastening an insertion instrument can be attached to the part of the implant facing away from the insertion part.

The intervertebral distraction implants according to the invention can be equipped with special guide elements to facilitate their rotation in the intervertebral disc space. On the distraction wedge C, these can consist of a specially shaped channel 7 or of such a channel with a strip 9 attached to it. On the actual implant body, the implant part D, the guide elements consist of the front edges 3a, 3b that become sharp towards the end of the wedge, the sharp-edged strips 15 possibly attached to the front front edge 3a, the grooves 7 and that continue from the distraction wedge into the adjacent part of the implant body possibly attached strips 9.

For the implantation of the intervertebral implant, a z. B. rod-shaped insertion instrument El with a handle and a plunger ES are provided, the front end of which has the same curvature as the rear end 13 of the implant.

The implants can be made of metal, polymer, or a composite material. The surfaces of the implants can be smooth, structured or coated.

From the surfaces 2a, 2b of an implant according to the invention, structures such as B. small cones, prisms or strips can be arranged in such a way that they form rows running parallel or concentrically to the front edges of the implant so that they can also act as guide elements.

Radiological shading elements or materials are incorporated into implants made of polymer or composite material to make them visible in x-rays. List of numbering and abbreviations used in the drawings and used in the description:

1a - base of the distraction wedge 1b - upper surface of the distraction wedge 1 c - lower surface of the distraction wedge 1 d - front end of the distraction wedge

2a - upper surface of the implant part D 2 b - lower surface of the implant part D

3 a, 3b - sharp front edges of the implant part D

4 - Rounded leading edge surface of the implant part D

5 - Device for fastening an insertion instrument

6 - Central recess in the surface of the implant part D

7 - Guide trough in distraction wedge C and implant part D

7a - vertical rear wall of the guide trough 7

7 b - From the depth of the channel 7, the channel surface ascending obliquely against the surfaces 1b and 1c

8 - Sharp rear edge of the guide trough 7

9 - Sharp-edged strip attached to 7a

10 a - front wall of the implant 10 b - rear wall of the implant

12 - The wedge end of the implant part D

13 - The end of the implant part D opposite the wedge-side end

14 - Rounded transition of the wedge surfaces 1b and 1c into the implant surfaces 2a and 2b

15 - Sharp-edged bar attached to the front leading edges 3 a near the distraction wedge C.

16 - Body of a distractor

17 - Wedge of a distractor body.

18 - Handle of a distractor body

19 - Height of a distractor body AF - annulus fibrosus, intervertebral disc ring

BR - intervertebral disc space

C - distraction wedge

D - Pressure transmitting implant part

El - introducer

ER - direction of insertion

ES impact ram

GF - articular process

I - implant body

IA - longitudinal implant axis

SR - swivel direction of the insertion instrument

W - vortex

WK - vertebral body

Claims

Applicant: Sepitec Foundation FL-9490 Vaduz (Liechtenstein) Subject: Implant for stabilization operations on the thoracic and lumbar spine

1. Implant for stabilization operations on the thoracic and lumbar spine to restore the resilience of the vertebral body column, characterized in that the implant part has a wedge-shaped bevel at its insertion area, which enables the vertebral bodies to be pushed apart to enlarge the intervertebral distance.

2. Implant according to claim 1, characterized in that it is formed from a wedge-shaped insertion part (distraction part C) and a pressure-transmitting implant part (D).

3. Implant claim 1 or 2, characterized in that the angle enclosed by the wedge surfaces is at least approximately 30 °, preferably 25 ° to 30 °.

Implant according to claim 1, characterized in that its bottom, top and side surfaces are flat or slightly curved and parallel or inclined to one another.

5. Implant according to one of claims 1 to 4, characterized in that the surfaces thereof are smooth, structured or coated.

6. Implant according to claim 5, characterized in that its surfaces are equipped with outstanding structures, such as small cones, prisms or strips, which optionally form rows that run parallel or concentrically to the front edges of the implant.

7. Implant according to one of claims 1 to 6, characterized in that radiologically shadowing elements or substances are provided in the implant if the implant material itself is not radiologically shadowing.

Implant according to one of claims 1 to 7, characterized in that it has a device for fastening an implantation instrument.

9. Implant according to one of claims 1 to 7, characterized in that its front wall is convex and the rear wall is flat, convex or concave, the two end parts are cylindrically rounded, the end part with which the implant can be inserted into the intervertebral disc space, is longer than the other and part of the upper and / or lower surface of the longer part has a wedge-shaped bevel.

10. Implant according to claim 9, characterized in that surfaces which delimit a central recess run approximately parallel to the outer walls.

11. Implant according to claim 9, characterized in that in the case of implants with a central recess, the convex-side upper and lower front edges of the front and rear walls begin with sharp edges on the side of the wedge-shaped end and experience a rounding that increases towards the other end, and that in the case of implants without central recess at least the edges of the front wall are shaped in this way.

12. Implant according to one of claims 1 to 11, characterized in that guide elements in the form of channels and / or strips are provided in the wedge-shaped end part and / or in the implant part.

13. Implant according to claim 12, characterized in that grooves are worked into the upper and lower surface of the pressure-transmitting implant part adjacent to the recess on the wedge side, the edges of which are sharply executed and parallel or concentric to the sharp front edges, the channels or the strips attached to them possibly also running in a straight line.

14. Implant according to claims 12 and 13, characterized in that the grooves have the shape of an inverted pent roof-like, two-surface groove, the rear surface of which is perpendicular to the surface of the implant and forms a sharp edge with it, and the front surface of which is inclined towards the 0 - surface of the implant rises.

15. Implant according to claims 12 to 14, characterized in that the sharp edges of the channels run parallel or concentrically to the curvature of the corresponding portions of the front edges of the front wall.

16. Implant according to claims 12 to 15, characterized in that the edges of the channels are designed as straight lines and run obliquely through the surface of the implant in such a way that their direction lies parallel to a tangent which is at the transition from the cylindrical to the wedge-shaped Implant part is placed on the curvature of the front surface of the implant