DE20004693U1 - Vertebral implant for insertion in an intervertebral space - Google Patents

Description

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Vertebral implant for insertion into a vertebral space

The invention relates to a vertebral implant which is intended for insertion into a vertebral space in order to permanently grow together with the surrounding bone tissue as a spacer between adjacent vertebral bodies while maintaining the natural distance between the vertebral bodies.

Such vertebral implants are used in the case of degenerated or otherwise damaged intervertebral discs, especially in the case of removal of the intervertebral disc, in order to maintain the natural height of the intervertebral space, the reduction of which can otherwise be associated with great pain for the patient.

Such a vertebral implant is known, for example, from WO-95/08306, which has a cuboid-shaped, elongated base body which is provided with a hollow space running through it in its height direction and has a receiving device for receiving a handling tool at one end. The receiving device and the tool are designed in such a way that the vertebral implant can be rotated in its longitudinal direction by means of the tool, so that it can be inserted between the vertebral bodies with a width that ^is possibly smaller than its height and can be rotated while spreading the space between the vertebrae.

Another such vertebral implant is known from US 4,834,757, whose basic cuboid-shaped base body has an outer surface designed as a scale or barb structure in order to prevent the implant from accidentally slipping out of its final position between the vertebrae.

Another such vertebral implant is known from FR 97/10664, the base body of which is provided with

two attachments arranged at a distance from one another and pointing outwards. The attachments form two contact surfaces facing away from one another for contact with the cortical bone part of the vertebral bodies, so that the vertebral implant is securely supported on the edges of the vertebral bodies, preventing it from sinking into the vertebral bodies.

The invention provides a vertebral implant for insertion into the intervertebral space, in which the risk of sinking into the vertebral bodies in its final position between the vertebrae is low and which can nevertheless be inserted between the vertebrae easily and with little risk of injury to the surrounding tissue and can be produced inexpensively.

According to the invention, a vertebral implant is provided for insertion into an intervertebral space, which has a box-shaped, elongated base body which is provided with a cavity which runs through its height. The cavity serves to accommodate bone material, in particular 0 cancellous bone material which, compared to the harder cortical bone tissue, is better suited to growing together with surrounding bone tissue. The cavity is bordered by two opposing longitudinal walls and two opposing end walls. The transverse free edge surfaces of the end and longitudinal walls serve as contact surfaces between the vertebrae and the vertebral implant. The two end walls are thicker than the two longitudinal walls, with their transverse free edge surfaces being widened. The vertebral implant is made of a 0 fiber-reinforced plastic material.

The front walls, which are thicker than the longitudinal walls, form a broad support surface with their transverse edge surfaces, which are wider than the transverse edge surfaces of the longitudinal walls, for contact with the peripheral cortical sections of the vertebral bodies. The cortical outer edge of the vertebrae, which is harder than the spongy interior of the vertebrae, is sufficiently stable that during the period of

By forming a bone bridge through the implant, the compressive forces running in the longitudinal direction of the spine can be transferred to the implant, primarily via the outer edge of the vertebrae. The wide design of the contact surfaces means that excessive surface pressure between the contact surfaces and the vertebrae can be avoided, which could otherwise lead to the implant sinking into the vertebrae. The vertebrae are thus supported safely and permanently while maintaining the normal distance between the vertebral bodies.

The longitudinal walls can be made narrow because they hardly have to absorb any supporting forces. This means that the cavity can be enlarged, meaning that more bone material can be accommodated in the implant. This ultimately creates a larger and therefore more stable bone bridge between the vertebrae.

Because the supporting forces are almost completely absorbed by the wide edge surfaces formed by the front walls, it is also possible to remove the cortical end plates of the vertebral bones in the area between the two front walls of the vertebral implant without the risk of the implant sinking into the softer bone material in the vertebral bone. The partial removal of the cortical end plates of the vertebrae has the advantage that the bone material arranged in the cavity of the implant can come into contact with the spongy, softer bone material in the vertebra, which can further improve the growth of the bone material in the implant with the vertebral bone. Because the contact surfaces are formed integrally with the front walls due to the thickened design of the front walls of the implant, an integral implant construction is achieved with no projections or protrusions on the outside. The implant can therefore easily be provided on the outside in an overall rounded manner with broken edges. This has the advantage that it can be easily inserted into the intervertebral space without the risk of hitting the surrounding tissue.

This also prevents unwanted tissue damage. In order to achieve the largest possible bone bridge between the vertebrae, the cavity is designed with a shape that corresponds to the base body. This means that the cavity is also preferably box-shaped in its basic shape and its dimensions are close to the external dimensions of the base body in such a way that the front and longitudinal walls are still sufficiently stable with regard to the load-bearing and supporting effect of the implant.

The compact and simple design of the spinal implant according to the invention has the further advantage that the spinal implant can be produced efficiently and thus economically and is thus particularly suitable for series production. The number of additional processing steps, in particular machining steps, is reduced. The compact design of the implant makes it possible to provide fiber-reinforced plastic material, such as glass fiber and/or carbon fiber composite material (CFRP), as the implant material, the use of which is preferred for implants for cost reasons and because of the long service life and good tolerance by the human organism. An implant with a more complicated structure, on the other hand, is rather unsuitable for the use of fiber composite material, since a reliable strength design of a complicated component is difficult when using fiber composite materials. The implant material preferably has long carbon fibers, in particular continuous carbon fibers, with which a specifically high implant strength can be achieved with inexpensive production of the implant. Furthermore, it is advantageous to add an X-ray contrast agent to the implant material so that the final position of the implant can be checked at any time by means of X-rays.

5 After the implant has been inserted into the intervertebral space, the implant is held in place by the contact pressure generated by the vertebrae and by a prefabricated bed, which may have been previously created, for example, by milling in the tissue.

was formed, is held in position. In order to better prevent the implant from slipping from its final position, the outer surface of the implant can be roughened as a whole, as a result of which the surrounding tissue slightly interlocks with the rough outer skin of the implant, which counteracts unintentional implant movement. Advantageously, a notch is formed in each of the transverse free edge surfaces of the end walls, which runs in the width direction of the base body. The notch has the advantage that it can be easily formed integrally in the implant body, as it does not protrude from the latter. The notch also does not hinder the easy insertion of the implant into the intervertebral space. It also causes the bone tissue, which rests under pressure on the contact surface of the implant, to settle slightly in the notch, as a result of which the implant is fixed in its longitudinal direction. By inserting the implant in its longitudinal direction into the intervertebral space, the fixation in the width direction of the implant can be achieved by forming a groove in the vertebrae that is adapted to the width of the implant, into which the implant can be inserted in its width direction in a form-fitting manner with the groove and thus laterally fixed.

Although the implant can, for example, be designed as a strictly mathematical cuboid shape with straight side edges and flat side surfaces, the base body advantageously has a convex shape in its width direction with each long side curved outwards. This shape has the advantage that the implant can be fitted directly between the vertebral bodies without prior machining, since the natural shape of the frontal vertebral end plates, viewed in the lateral direction of the spine, is concave on both sides in accordance with the convex shape of the implant. The mouth sides of the implant, i.e. those implant sides where the cavity opens, are therefore also curved, so that the bone material arranged in the implant is in contact with the

surrounding vertebral bones. The positive convex-concave fit achieved between the implant and the vertebral bodies has the further advantage that the implant is protected in its longitudinal direction against slipping out of its final position. The other two side surfaces of the base body, i.e. the outer surfaces of the longitudinal walls, are preferably parallel to each other and flat, which, as explained below, has advantages with regard to inserting the implant into the intervertebral space.

Although the thickness ratio of the longitudinal and front walls can be selected differently, the two front walls are advantageously at least twice as thick, preferably 2.5 times as thick, as the longitudinal walls. With these thickness ratios, there is a very good ratio, which achieves stable support of the vertebrae with minimal space required for the vertebral implant and maximum cavity size to form a large bone bridge between the vertebrae.

Preferably, at least one through hole is formed in each of the two longitudinal walls of the cavity. This also allows the implant to grow into the surrounding (bone) tissue from the side or all around, making the implant more securely seated in the long term. Furthermore, the lateral through holes allow the surrounding blood vessels access to the bone, improving its nutrient supply and ultimately the growth of the implant. Although a large number of smaller holes can be formed in the longitudinal walls, the diameter of which is small in relation to the height of the longitudinal wall, preferably a maximum of two large through holes are formed in the longitudinal walls, the diameter of which corresponds to approximately half the height of the longitudinal walls at the longitudinal position at which the through hole is provided. As a result, as soon as the cavity is filled with bone material, it is pushed outwards from the lateral through holes and can then come into contact with the

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surrounding tissue.

The vertebral implant according to the invention can be inserted lengthwise into the intervertebral space directly in its intended final orientation. However, if the natural height of the intervertebral space and thus the implant height is greater than the implant width, as is the case in particular with implants inserted between the lumbar vertebrae, and if the preferred convex-shaped implant is used, it is advantageous to insert the implant into the intervertebral space rotated by 90° in its longitudinal direction with its flat side surfaces resting against the vertebral bodies. It is then then necessary to rotate the implant back into its final position by 90° in its longitudinal direction, possibly by spreading the intervertebral space. In order to be able to use this advantageous insertion method, the base body preferably has a receiving device on its rear, front end section for receiving a handling tool, so that a torque can be exerted on the base body in the longitudinal direction of the base body using the latter. The receiving device is advantageously designed in such a way that the implant can be easily and firmly attached to the handling tool, so that the latter can also be used as an insertion tool for inserting the implant into the intervertebral space.

The receiving device preferably has a hole 0 formed centrally in the front wall of the base body and open to the outside and two grooves formed to the side of the hole in the front wall of the base body, which are open to the outside. This receiving device, which is provided countersunk in the base body, keeps the implant free of protrusions or projections. Corresponding counterparts on the tool can engage in the central hole and the side grooves 5. The hole serves to align the implant with the tool and, as explained using the embodiment described below, can also be used to hold the implant on the tool.

can be used. The tool can apply a torque to the implant in its longitudinal direction, i.e. around its longitudinal direction, via the two grooves.

In order to prevent the handling tool from slipping off the implant, the receiving device is advantageously designed in such a way that it also serves as a holding device. The handling tool can, for example, be provided with a clamp with which the implant can be held in place, for example by engaging in the notches. According to a preferred embodiment of the invention, however, the hole in the receiving device is designed as a threaded hole. This allows a corresponding counterpart of the handling tool, such as a threaded bolt, to be firmly screwed to the implant, so that the implant is connected to the handling tool as a component and can be moved by the surgeon together with the latter and thus handled precisely. In order to determine the position of the implant in relation to the handling tool even more precisely, the threaded hole can be designed as a through hole 0 and a through hole aligned with the through hole of the receiving device can be formed in the front wall at the other end section of the base body. This allows a corresponding part on the handling tool to engage in the 5 through hole at the other end of the implant while centering the implant to the tool.

The frontal through holes also promote the ingrowth of surrounding tissue into the implant.

0 The vertebral implant according to the invention is preferably provided with the following mechanical properties:

- static compressive strength in height direction: > 15,000 N

- the fatigue strength associated with this compressive strength: > 5,000 N

- Torsional strength (torque in (around) longitudinal direction of the implant): > 4 Nm

An advantageous method for producing vertebral implants made of fiber composite material, such as glass or carbon fiber composite material (GRP or CFRP), is explained below. This method is preferred for producing the vertebral implant according to the invention.

In a first step, fibers soaked in liquid plastic, in particular resin material such as epoxy resin, are wound around a winding mandrel. The fibers are preferably carbon fibers. The fibers are advantageously wound around the winding mandrel as fiber bundles, in particular using the filament winding process. The plastic is then cured; this is best done by controlled temperature treatment. By wrapping the winding mandrel, which is advantageously simply rod-shaped, an elongated base body made of fiber composite material with a cavity is formed. The final dimensions of the cavity are already formed by the winding mandrel, so that machining of the inner surfaces of the boundary walls surrounding the cavity is no longer necessary.

In a next step, the base body is machined on its outside in such a way that it has an equidistant undersize on all sides compared to its final external dimensions. The undersize is advantageously close to the later final size so that as little material as possible has to be machined in the machining step. For the same reason, in the winding step explained above, fiber material is preferably wound around the winding mandrel until the base body has reached at least the undersize mentioned above on all sides. It should be noted here that the base body cannot be wound exactly to the final size or undersize on all sides, so that in addition to the places where the undersize is reached, there are places where more plastic material is wound onto the mandrel. Milling, grinding and/or polishing processes can be used as machining processes. In the machining step

the different wall thicknesses of the longitudinal and end walls are preset by appropriate machining from the outside of the base body. During the machining step, a mandrel is advantageously accommodated in the cavity of the base body in exchange for the winding mandrel, which serves to clamp the base body precisely and centrally in the clamping device of the machining machine. In the next step, fibers that are soaked in plastic are again wound around the base body until the final external dimensions of the implant are almost reached. This means that plastic material is wound around the base body until it has at least reached the final dimension at every point on the outside, although, as explained above, the base body cannot be wound to the final dimension on all sides.

This second winding process preferably corresponds to the first winding process in terms of the materials used and the winding method. The second winding step is carried out with the winding mandrel inserted. In the last step, the base body is machined on the outside in a second machining step until its final external dimensions are achieved. This second machining step is preferably carried out in the same way as the first machining step.

The method described achieves the most closed fiber path possible on the inner and outer surfaces of the implant, thereby making optimal use of the strength-enhancing properties of the fiber material. In particular, a completely closed fiber path is achieved on the cavity boundary surfaces (inner surfaces), since no further machining step is required there after winding. Since two winding steps are also provided for the manufacture of the base body, only a small amount of material needs to be removed from the base body in the second machining step, so that no deep damage to the fiber winding occurs on the outer plastic layers of the base body. The undersize compared to the final external size of the base body should therefore preferably be selected so that a sufficiently thick winding layer can still be applied, but that the

Thickness differences of the winding layers further wound on the base body are not too large in order to avoid damaging too many fibers during machining.

It is considered advantageous if the undersize after the first machining step is approximately 90-98%, preferably 95%, of the final external dimension of the base body.

Optionally, after the second winding process and after the plastic has hardened, holes and grooves are introduced into the base body in addition to the cavity by appropriate machining steps. In the case of the vertebral implant according to the invention, these are the holes in the longitudinal and end walls as well as the grooves of the receiving device and the notches in the transverse free edge surfaces of the end walls.

The invention is explained below using preferred embodiments with reference to the drawing. 0 In the drawing:

Figure 1 is a three-dimensional view of a vertebral implant according to an embodiment of the invention,

5 Figure 2 is a side view of a vertebral implant according to another embodiment of the invention,

Figure 3 is a front view of the vertebral implant of Figure 2, 30

Figure 4 shows a longitudinal section of the vertebral implant of Figure 2 along a section line marked B-B,

Figure 5 is a sectional view of the vertebral implant of Figure 2 along a section line marked A-A,

Figure 6 is a rear view of the vertebral implant of Figure 2, and

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Figure 7 is a schematic representation of the vertebral implant according to the invention inserted between two vertebral bodies.

As can be seen from the figures, the spinal implant 1 according to the invention is formed by a cuboid-shaped, elongated base body 2. A central cavity 3 is formed in the base body 2, which is surrounded by two longitudinal walls 4, 5 and two end walls 6, 7 of the base body 2. The cavity 3 is continuous in the height direction H of the base body 2 and is provided in plan as an elongated rectangle with semicircles flush on the front. The cavity 3 has the same plan over the entire height of the implant and is thus formed without undercuts in the base body 2. The front-side boundary walls 6, 7 are overall, i.e. over their entire wall surface, thicker than the longitudinal boundary walls 4, 5. Any recesses formed in the front-side boundary walls 6, 7 are arranged and dimensioned in such a way that the boundary walls 6, 7 are not significantly weakened, as in the embodiment shown, the front-side boundary walls 6, 7 are approximately 2.5 times as thick as the longitudinal boundary walls 4, 5 of the cavity 3; the thickness in the middle of the respective wall is used as the relevant wall thickness. As a result, the base body 2 has, at the top and bottom, on its two opening sides, i.e. on the two long sides at which the cavity 3 opens, transverse free edge surfaces 8, 8', 9, 9' formed by the end faces of the end walls 6, 7, which are wider than the respective transverse free edge surfaces 10, 10', 11, 11' formed by the end faces of the long walls 4, 5. These edge surfaces 8, 8', 9, 9' formed on the end face each run continuously and without any steps. As can be seen from Figure 7, they serve as edge-side contact and support surfaces for the vertebral bodies W and absorb the forces occurring between the vertebrae W almost completely. For this purpose, use is made of the fact that the vertebral bodies W have harder, cortical bone material K in their outer area.

while inside the vertebral body W there is softer, spongy bone material S. The peripheral shell of the vertebral bone W, which consists of cortical bone tissue and to which the front walls 6, 7 of the implant 1 engage via the contact surfaces 8, 8', 9, 9', is sufficiently stable to absorb the compressive forces running in the longitudinal direction of the spine during the time of formation of the bone bridge and to transfer them to the implant 1 at the edge.

The base body 2 has, in the side view in the width direction B, i.e. parallel to the contact surfaces 8, 8', 9, 9', a longitudinally bi-convex shape with a maximum bulge provided approximately in the longitudinal center (see Figures 2, 5 and 7). Due to this lens-shaped design of the base body 2, seen in the width direction of the implant, it can be placed tightly in the intervertebral space, which, seen in the side view of the human spine, has a concave shape corresponding to the convex shape of the base body 2. This ensures, on the one hand, that the bone material received in the vertebral implant 1 is in contact with the vertebral bodies W along the entire length of the cavity 3, which helps them grow together better. On the other hand, the concave-convex connection achieved in this way between the vertebral implant 1 and the vertebra W counteracts an unintentional slipping out of the intervertebral space of the implant 1.

In the top view, i.e. seen perpendicular to the contact surfaces 8, 8', 9, 9', the vertebral implant 1 is designed as an elongated rectangle with straight side lines (see Figure 4).

The corners 12 of this rectangular shape are rounded, so that the implant 1 tapers towards the front due to its lens-shaped design in the width direction B (see also Figure 3). The radius of the roundings 12 is approximately 5 1/3 of the implant width. As can be seen from Figures 1 and 3, the longitudinal and front edges of the implant 1 are also rounded. This allows the implant to be inserted into the

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The edge of the openings of the cavity 3 is preferably not rounded and thus forms an edge. This saves a processing step, which further reduces manufacturing costs. With regard to this edge, there is almost no risk of injury to the tissue when inserting the implant because, in contrast to the longitudinal and frontal edges of the implant, it is located further inwards. Towards the rear of the implant 1, the latter tapers due to its lens shape until it reaches the front wall 7, the contact surfaces 9, 9' of which then run approximately parallel to the longitudinal direction of the implant 1 when viewed in the lateral direction of the implant 1 (cf. Figures 2, 5 and 7).

In those contact surfaces 8, 8', 9, 9', which are formed by the end walls 6, 7, a notch 13 is formed which runs continuously in the width direction B of the implant 1. The respective notch 13 is provided as a triangular groove, the side flanks of which form an angle of 90° to one another; however, other groove shapes, such as a rectangular or U-shape, are also possible. Due to the pressure forces prevailing between the two vertebrae W, the bone tissue of the vertebrae W is partially pressed slightly into the notches 13, whereby additional anchoring of the implant 1 in its final position is achieved. At the rear end of the base body 2 (shown as the right end in Figures 1, 2, 4, 5 and 7), a receiving device 14 for a handling tool (not shown) is provided. The receiving device 14 has a through hole 15 formed centrally in the front wall 7, which is provided with an internal thread into which a section of the handling tool provided with a corresponding external thread can be screwed. To the side of the through hole 15, namely on those sides of the implant 1 which face away from the cavity openings, a groove 16, 16' is introduced into the respective rounded corner surface 12 of the front wall 7, into which the handling tool jjy.t a corresponding counterpart

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engages when the implant is screwed onto the handling tool. This allows the handling tool to exert a torque in the longitudinal direction of the vertebral implant via the grooves 16, 16' in order to rotate the same.

In the front end wall 6 of the base body 2, a through hole 17 is formed in the middle, aligned with the threaded hole 15. A corresponding counterpart of the handling tool can engage in the through hole 17 in order to center the implant 1 with respect to the tool. The through hole and the threaded hole then also enable bone growth into the front side of the implant 1, which improves its fit.

In the embodiment according to Figure 1, two through holes 18, 18', 19, 19' are formed in the longitudinal walls 4, 5 of the cavity 3, whereas in the embodiment according to Figures 2 to 6, one through hole 18, 18' is formed in the longitudinal walls 4, 5. The diameter of the through holes 18, 18', 19, 19' corresponds approximately to half the height of the implant 1 at the longitudinal position of the respective through hole 18, 18', 19, 19'. Bone growth can occur sideways through these through holes 18, 18', 19, 19', which serves to anchor the vertebral implant 1 even better in the intervertebral space.

Claims (22)

1. Vertebral implant ( 1 ) for insertion into a space between the vertebrae, which has a box-shaped, elongated base body ( 2 ) which is provided with a cavity ( 3 ) which is continuous in its height direction (H) for receiving bone material and which is bordered by two opposing longitudinal walls ( 4 , 5 ) and by two opposing end walls ( 6 , 7 ), the transverse free edge surfaces ( 8 , 8 ', 9 , 9 '; 10 , 10 ', 11 , 11 ') of which serve as contact surfaces between the vertebrae (W) and the vertebral implant ( 1 ), wherein the two end walls ( 6 , 7 ) of the cavity ( 3 ) are thicker than the two Longitudinal walls ( 4 , 5 ) and wherein the implant ( 1 ) is made of a fiber-reinforced plastic material. 2. Vertebral implant ( 1 ) according to claim 1, wherein a notch ( 12 , 12 ', 13 , 13 ') is formed in each of the transverse free edge surfaces ( 8 , 8 ', 9 , 9 ') of the two end walls ( 6 , 7 ), which notch runs in the width direction (B) of the base body ( 2 ). 3. Vertebral implant ( 1 ) according to claim 1 or 2, wherein the base body ( 2 ) has a shape which is curved outwards on each longitudinal side when viewed in its width direction (B). 4. Vertebral implant ( 1 ) according to one of claims 1 to 3, wherein the two end walls ( 6 , 7 ) are at least twice as thick, preferably 2.5 times as thick, as the longitudinal walls ( 4 , 5 ). 5. Vertebral implant ( 1 ) according to one of claims 1 to 4, wherein at least one through hole ( 18 , 18 ', 19 , 19 ') is formed in each of the two longitudinal walls ( 4 , 5 ) of the cavity ( 3 ). 6. Vertebral implant ( 1 ) according to one of claims 1 to 5, wherein the base body ( 2 ) has at a front end portion a receiving device ( 14 ) for receiving a handling tool such that a torque can be exerted on the base body ( 2 ) in the longitudinal direction of the latter. 7. Vertebral implant ( 1 ) according to claim 6, wherein the receiving device ( 14 ) has a hole ( 15 ) formed centrally in the front wall ( 7 ) of the base body ( 2 ) and open to the outside and two grooves ( 16 , 16 ') formed laterally of the hole ( 15 ) in the front wall ( 7 ) of the base body ( 2 ) and which are open to the outside. 8. Vertebral implant ( 1 ) according to claim 7, wherein the hole ( 15 ) of the receiving device ( 14 ) is designed as a threaded hole. 9. Vertebral implant ( 1 ) according to one of claims 1 to 8, wherein the implant material comprises wound long carbon fibers. 10. Vertebral implant ( 1 ) according to one of claims 1 to 9, wherein the implant material comprises an X-ray contrast agent. 11. Vertebral implant ( 1 ) according to one of claims 1 to 10, wherein the two longitudinal walls ( 4 , 5 ) run parallel to each other. 12. Vertebral implant ( 1 ) for insertion into a space between the vertebrae, which has a box-shaped, elongated base body ( 2 ) which is provided with a cavity ( 3 ) which is continuous in its height direction (H) for receiving bone material and which is bordered by two opposing longitudinal walls ( 4 , 5 ) and by two opposing end walls ( 6 , 7 ), the transverse free edge surfaces ( 8 , 8 ', 9 , 9 '; 10 , 10 ', 11 , 11 ') of which serve as contact surfaces between the vertebrae (W) and the vertebral implant ( 1 ), wherein the two end walls ( 6 , 7 ) of the cavity ( 3 ) are thicker than the two Longitudinal walls ( 4 , 5 ), wherein the implant ( 1 ) is made of a fiber-reinforced plastic material and wherein the implant is designed without any projections on the outside. 13. Vertebral implant ( 1 ) according to claim 12, wherein a notch ( 12 , 12 ', 13 , 13 ') is formed in each of the transverse free edge surfaces ( 8 , 8 ', 9 , 9 ') of the two end walls ( 6 , 7 ), which notch runs in the width direction (B) of the base body ( 2 ). 14. Vertebral implant ( 1 ) according to claim 12 or 13, wherein the base body ( 2 ) has a shape which is curved outwards on each longitudinal side when viewed in its width direction (B). 15. Vertebral implant ( 1 ) according to one of claims 12 to 14, wherein the two end walls ( 6 , 7 ) are at least twice as thick, preferably 2.5 times as thick, as the longitudinal walls ( 4 , 5 ). 16. Vertebral implant ( 1 ) according to one of claims 12 to 15, wherein at least one through hole ( 18 , 18 ', 19 , 19 ') is formed in each of the two longitudinal walls ( 4 , 5 ) of the cavity ( 3 ). 17. Vertebral implant ( 1 ) according to one of claims 12 to 16, wherein the base body ( 2 ) has at a front end portion a receiving device ( 14 ) for receiving a handling tool such that a torque can be exerted on the base body ( 2 ) in the longitudinal direction thereof. 18. Vertebral implant ( 1 ) according to claim 17, wherein the receiving device ( 14 ) has a hole ( 15 ) formed centrally in the front wall ( 7 ) of the base body ( 2 ) and open to the outside and two grooves ( 16 , 16 ') formed laterally of the hole ( 15 ) in the front wall ( 7 ) of the base body ( 2 ) and which are open to the outside. 19. Vertebral implant ( 1 ) according to claim 18, wherein the hole ( 15 ) of the receiving device ( 14 ) is designed as a threaded hole. 20. Vertebral implant ( 1 ) according to one of claims 12 to 19, wherein the implant material comprises wound long carbon fibers. 21. Vertebral implant ( 1 ) according to one of claims 12 to 20, wherein the implant material comprises an X-ray contrast agent. 22. Vertebral implant ( 1 ) according to one of claims 12 to 21, wherein the two longitudinal walls ( 4 , 5 ) run parallel to each other.