EP1624831A1

EP1624831A1 - Device for implanting in a human or animal vertebral column

Info

Publication number: EP1624831A1
Application number: EP04738530A
Authority: EP
Inventors: Peter Metz-Stavenhagen
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-05-19
Filing date: 2004-05-19
Publication date: 2006-02-15
Also published as: WO2004103225A1; DE112004001375D2; DE20307876U1; US20100292794A1

Abstract

The invention relates to a device for implanting in a human or animal vertebral column, said device comprising a base carrier (10) that can be fixed to a first vertebral body, an upper carrier (14) that can be fixed to a second vertebral body, and a spacer element fixed between the base carrier and the upper carrier. The base carrier (10) and/or the upper carrier (14) are provided with a cavity (18, 24) comprising undercuts, for receiving the spacer element in a positively locked manner. The aim of the invention is to economically create one such device that ensures complete freedom of movement of the vertebral column. To this end, the spacer element is embodied as metallic bellows (12).

Description

Device for implantation in a human or animal spine

The present invention relates to a device for implantation in a human or animal spine according to the preamble of claim 1. The human spine is formed from different vertebral bodies, each separated from one another by an intervertebral disc (colloquially called an intervertebral disc) and padded against one another. These intervertebral discs consist of a fibrous outer shell that contains a gel-like liquid. The intervertebral discs are subject to large forces that can vary from about 780 N to as much as about 2200 N. Due to the high stressing forces, the intervertebral discs wear out frequently, especially in old age. Since an intervertebral disc that has been destroyed cannot heal again, damaged intervertebral discs are usually removed and the adjacent vertebral bodies are fused together. However, this has the disadvantage that the spine is then stiff in this area.

DE 38 73 566 T2 proposes that adjacent vertebral bodies be separated by an implant having a spring in order to keep the spine movable in this area. This implant consists of a base support and a top support, each of which is fixed to the corresponding side of the vertebral body and a spring element consisting of two coil springs, which is held on the base support and the top support. At the same time, the base support and top support are connected to one another via a common axis in such a way that both can be pivoted about this axis. With this implant, adjacent vertebral bodies remain movable in the swivel direction, so that a patient provided with such an implant can bend down again. Unfortunately, due to the rigid pivot axis, movement to the right or left is not possible, so that with one patient provided with such an implant only has limited freedom of movement.

The implant according to DE 38 73566 T2 consists of a large number of individual parts, which makes their production very expensive. In addition, with the many individual parts, there is a risk that tissue will grow together with the result that pinched tissue then leads to pain or other disabilities.

From DE 43 15 757 C1 an implant is known which has a spring-elastic intermediate element. This intermediate element is composed of a number of essentially cylindrical discs which are elastic in the axial direction, the outer wall of the disc optionally being concave or convex in order to absorb the forces occurring in the axial direction in a spring-elastic manner. However, the connection points between adjacent panes are subject to very high loads, so that damage can occur here. In addition, the implants are made in one piece, so that a complete implant has to be stored for each application, which leads to considerable costs.

An implant is known from US Pat. No. 5,370,697, which is constructed in a modular construction. This implant consists of a top and a base element, with a non-resilient tube that can be used as a spacer in between to bridge the missing intervertebral disc or the missing vertebrae. The elasticity of the spine is lost.

Proceeding from this, the object of the present invention is to create a device for implantation into a human or animal spine, which ensures complete freedom of movement of the spine at low manufacturing costs. A device with the features of claim 1 is proposed according to the invention as a technical solution to this problem. Advantageous developments of this device can be found in the subclaims.

A device for implantation into a human or animal spine designed according to this technical teaching has the advantage that the spring element designed as a bellows can be pivoted in all directions and at the same time has such high rigidity that there is no further connection between the base support and the top support can be. The bellows has the further advantage that it can be bent in the desired direction without large forces acting on the base support and / or the top support. As a result, the load on the screws fixing the base support and / or the top support is kept low.

In a preferred embodiment, undercuts, in particular in the form of a dovetail connection, are provided in the base support and / or in the top support on the side facing the bellows, which receive parts of the bellows in a form-fitting manner. It is easily possible, for example, to first push the bellows into the base carrier in such a way that the last shaft is fitted to the receptacle. The top carrier can then also be pushed onto the corrugated bellows fixed in such a way that the uppermost crest of the corrugated bellows enters the receptacle. The great advantage of this system is that it firstly screws the base support to the vertebral body, for example using pedicle screws, before the spring element designed as a bellows is inserted into the receptacle and before the top support is pushed onto the bellows. This results in a simple implantation in the device during the operation on the spine.

It has proven to be advantageous to limit the undercuts on one side with a stop so that the bellows cannot accidentally slip out, at least on this side, and above all, so that the doctor when inserting the bellows into the base or top part knows how far the bellows should be inserted. This results in an exact placement of the bellows relative to the base and / or top part.

In an alternative, preferred embodiment, the base support and / or the top support is connected to the bellows via a bayonet connection. This makes it possible to connect the bellows to the base and / or top support in a simple manner, even during the operation

In another preferred embodiment, a vertically protruding cutting edge is attached to a side of the top carrier facing the vertebral body. With this cutting edge, the device implanted in the manner described above is then brought into its final position, the cutting edge cutting into the vertebral body arranged above the top carrier and thus being secured against sliding sideways.

In a further preferred embodiment, on a side of the top support and the base support facing the vertebral body, some vertically projecting spikes are attached which penetrate the respective vertebral bodies and prevent the device from rotating.

In another preferred development, the top carrier is wedge-shaped in cross-section in order to compensate for the curvature of the spine, so that the bellows can run essentially in a straight line.

In yet another preferred embodiment, the top carrier has a rectangular cross section, while some wave troughs and / or wave crests are wedge-shaped in cross section in order to achieve a structural curvature of the wave crest.

Further advantages of the device according to the invention result from the attached drawing and the embodiment described below. to form. Likewise, according to the invention, the features mentioned above and those which are explained further can be used individually or in any combination with one another. The mentioned embodiments are not to be understood as an exhaustive list, but rather have an exemplary character. Show it:

Fig. 1 is a side view of a human spine together with a first embodiment of the device according to the invention in

Exploded view; FIG. 2 shows an exploded view of the device according to FIG. 1; 3 shows the device according to FIG. 1 in a front view; Fig. 4 is a side view of a human cervical spine together with a second embodiment of the device according to the invention in

Exploded view; 5 shows the second embodiment of a device according to the invention according to FIG. 4 in a side view; 6 shows the device according to FIG. 4 in a front view; 7 shows a side view of a third embodiment of a device according to the invention; FIG. 8 shows a front view of the device according to FIG. 7;

9 shows a side view of a fourth embodiment of a device according to the invention; FIG. 10 is a front view of the device according to FIG. 9; Figure 1 1 is a side view of a fifth embodiment of a device according to the invention;

FIG. 12 shows a front view of the device according to FIG. 11;

The first embodiment of a device according to the invention for implantation into a human or animal spine shown in FIGS. 1 to 3 comprises a base support 10 made of a rigid material, a spring element designed as a bellows 12 and a top support 14. As can be seen in particular in FIG. 2 openings 16 are provided on the base support for receiving a bone screw, with which the base support 10 on the vertebral body is attachable. The bone screw is made from a biomaterial that resorbs in the body over time, during which time the top 14 and the base support 10 have become attached to the vertebral bone.

The metallic bellows 12 has a wave-shaped outer contour, with individual wave troughs 21 and wave crests 22 enclosing the wave bellows 12 in a ring. This bellows 12 is modeled, for example, on a corrugated hose. Furthermore, the base support 10 has on its side facing away from the vertebral body a receptacle 18 for fastening the bellows 12 to the base support 10. The cross section of this receptacle 18 is adapted to the contour of a wave trough 21 and a wave crest 22 of the wave bellows 12 and has two in the receptacle 18 protruding webs 20. The bellows 12 with its last wave crest 22 is inserted laterally into the receptacle 18 and held there positively on the base carrier 10 by the webs 20. On the side of the top carrier 14 facing the bellows 12, a second receptacle 24 is provided, which is designed analogously to the first receptacle 18. Here, too, the bellows 12 with its outer crest 22 can be inserted into the receptacle 24 in order to be held in a form-fitting manner.

The top carrier 14 is wedge-shaped in cross section and has a vertically protruding cutting edge 26 in the center. The cutting edge 26 is oriented perpendicular to the longitudinal direction of the receptacle 24. The top carrier 14 and the base carrier 10 are provided with a commercially available coating in order to connect well and quickly to the vertebral bone.

It goes without saying that the device according to the invention is manufactured in different sizes. The size of the top bracket 14 and / or the base bracket 10 varies in order to provide a suitable dimensioned specimen for each vertebra. The length and spring properties of the bellows 12 also vary. Only the diameter of the bellows 12 and the corresponding receptacles 18, 24 are the same for all devices, so that each base support 10 can be combined with each bellows 12. The second embodiment of the device according to the invention shown in FIGS. 4 to 6 is essentially identical to the first embodiment shown in FIGS. 1 to 3, and differs only in that in this second embodiment the bellows 27 designed as a corrugated hose is slightly curved and that the top carrier 28 is not wedge-shaped, but is rectangular in cross section. The wave troughs 29 are differently widened or narrowed according to the curvature, while the waves 22 remain unchanged.

In addition to the first embodiment, in this second embodiment, a plurality of spikes 32 are attached to the sides of the top support 28 and the base support 30 facing the vertebral bones, which extend into the respective vertebral bones and prevent the device from rotating. Like the bone screws, these spikes 32 are made of a resorbing biomaterial.

The third embodiment shown in FIGS. 7 and 8 differs from the second embodiment shown in FIGS. 4 to 6 in that the curvature of the bellows 34 is not compensated for by the wave troughs, but here by the waves 36. Accordingly, the shaft 36 is made narrower on the inside of the curve than on the outside of the curve.

The device for implantation in a human or animal spine is used regularly when an intervertebral disc between two vertebral bodies is irreparable and has to be removed. In some cases, one or more of the adjacent vertebral bodies are also affected and must also be removed in whole or in part. The device according to the invention then takes its place. It has proven to be advantageous for the device according to the invention in the lumbar spine in the intervertebral space between the fourth and fifth Use lumbar vertebrae, because stiffening the spine is the most problematic.

To implant the device according to the invention, the treating surgeon first attaches the base support 10 to the lower vertebral body with the aid of bone screws (not shown here) before the bellows 12 is inserted laterally with its last crest 22 into the receptacle 18 of the base support. Subsequently, the top carrier 14 is pushed onto the uppermost wave crest 22 of the wave bellows 12, the wave bellows 12 being bent so strongly that access is possible.

After the device is assembled in this manner, the surgeon pushes the bellows 12 into the desired position, the bellows 12 forming a connection between the lower part of the spine and the upper part of the spine. The top carrier 14 is brought with its cutting edge 26 to the vertebral body lying above it in such a way that the cutting edge 26 penetrates into it. In addition, the top carrier 14 is fixed using generally customary methods.

The top support 14 and the base support 10, implanted in this way, grow together with the respective vertebral bones, supported by the coating that supports the growing together. At the same time, the body resorbs the screw bones made from biomaterial.

It goes without saying that the operating doctor uses such a bellows 12, which in individual cases has the suitable length and the suitable spring properties.

As shown in FIG. 4, the device according to the invention can also be implanted into the cervical spine with appropriate dimensions in the manner described above.

In the fourth embodiment shown in FIGS. 9 and 10, a stop 42 is formed on one side in the receptacle 24 top carrier 40, on which the top shaft 44 comes to rest. This allows the bellows 46 to be positioned exactly and also makes assembly easier because the doctor can now push the bellows 46 into the top 40 or base support 48 without having to pay attention to other details. The stop 42 is designed as a side wall of the top carrier 40 and has a receptacle 24, the contour of which corresponds to the contour of the shaft 44.

A stop 42 corresponding to the stop 42 of the top carrier 40 is also embodied in a receptacle 18 on the base part 48. However, the

The stop 42 of the base part 48 is arranged exactly on the other side, like the stop 42 of the top carrier 40, so that the two stops 42 are virtually opposite one another.

In the fifth embodiment shown in FIGS. 11 and 12, two radially projecting pins 56, 58 are attached to the bellows 50 on the uppermost and lowermost shafts 52, 54, respectively, which engage in corresponding recesses 60, 62 in the top 64 and base carrier 66 can be introduced. The pins 56, 58 in connection with the recesses 60, 62 form a bayonet connection. With this bayonet connection, the bellows 50 can be inserted quickly and easily into the top 64 or base support 66, the pins 56, 58 being inserted into the recesses 60, 62. By pivoting the spring element 50, the pins 56, 58 are then inserted deeply into the L-shaped recess 60, 62 and clamped, because the recesses are conically tapered. This jamming of the bayonet catch in the conically tapering recesses 60, 62 results in a good locking of the bellows 50 in the top 64 and / or base support 66, so that a later loosening of the connection is prevented. LIST OF REFERENCE NUMBERS

10 base beams

12 bellows

14 top carriers

16 opening

10 18 recording

20 bridge

21 trough

22 Wellenberg

24 recording

15 26 cutting edge

27 bellows

28 top carriers

29 trough

30 base carriers

20 32 thorn

34, 36 bellows

40 top carriers

42 stop

44 wave

25 46 bellows

48 base carriers

50 bellows

52, 54 shaft

56, 58 pens

30 60, 62 recess

64 top carriers

66 base carriers

Claims

Expectations:

1. Device for implantation in a human or animal spine with a base support (10) that can be attached to a first vertebral body, with a top support (14) that can be attached to a second vertebral body, and with a spacer element held between the base support and top support, wherein in the base support (10) and / or in

Top carrier (14) is provided with an undercut receptacle (18, 24) which receives the spacer element in a form-fitting manner, characterized in that the spacer element is designed as a spring element.

2. Device according to claim 1, characterized in that the spring element is designed as a metallic bellows (12).

3. Device according to claim 1, characterized in that in the base support (66) and / or in the top support (64) a bayonet catch (60, 62) is provided, which receives parts of the bellows (50) in a form-fitting manner.

Device according to one of the preceding claims, characterized in that a vertically projecting cutting edge (26) is attached to a side of the top carrier (14) facing the vertebral body.

Device according to one of the preceding claims, characterized in that the top carrier (14) is wedge-shaped in cross section.

6. Device according to one of the preceding claims, characterized in that a vertically projecting mandrel (32) is provided on a side of the top support (28) and / or the base support (30) facing the vertebral body.

7. Device according to one of the preceding claims, characterized in that a single wave trough (29) and / or a single wave crest (36) of the bellows (27, 34) is wedge-shaped in cross section.

8. Device according to one of the preceding claims, characterized in that a stop (42) is provided in the receptacle (18, 24).

9. The device according to claim 8, characterized in that the stop (42) in the receptacle (18) of the base support (48) is arranged on a different side than the stop (42) in the receptacle of the top support (40).