DE10113689C1 - Intervertebral implant - Google Patents

Abstract

In the case of an intervertebral implant with two arms running essentially parallel to one another, which form support surfaces for adjacent vertebral bodies on their outer sides, with a bridge connecting the arms at one end of the arms and with a bridge engaging between the arms at the other end and positioning them accordingly between the arms more or less spreading spacer, to simplify the positioning of the spacer, it is proposed that the spacer is an eccentric, which is rotatably arranged about an axis of rotation running parallel to the arms between the arms so that its eccentric outer surface on the Bears the inside of the arms and spreads the arms more or less depending on the angular position of the spacer element.

Description

The invention relates to an intervertebral implant two essentially parallel to each other Poor, on their outer sides support surfaces for be Form neighboring vertebral bodies with one on the arms a bridge connecting one end of the arms and engage with one on the other end between the arms the and this according to its positioning between spreading the poor more or less punching element.

Such intervertebral implants are, for example from DE 44 16 605 C1, US 5,554,191 A or FR 2 719 763 A1 known. This intermediate vertebra is common implants that the arms are raised by spacers be spread in the longitudinal direction of the arms between these are pushed in and at an incline sliding surfaces so that depending on the Depth of insertion of the spacer one under different arms spread, this is a different angle of the support surfaces for the form adjacent vertebrae.

In the known intervertebral implants of this type become screw spindles for moving the spacer elements elements and this means for the surgeon  that setting the desired spread with a larger number of rotary movements is connected to it So it takes a long time until the desired degree of spreading is also difficult to control how strong spreading has occurred.

It is an object of the invention, a generic Zwi vertebra implant so that the spread arms is relieved.

This task is done with an intervertebral implant of the type described in the introduction solved that the spacer is an eccentric to an axis of rotation running parallel to the arms is rotatably arranged between the arms such that its eccentric outer surface is on the inside the arms against this and depending on the angular position of the Spacer spreads the arms more or less.

With such a configuration, the surgeon can solely by twisting the spacer a relatively small angle of rotation, for example in the Order of magnitude of maximum 90 °, the spread spread Chen, a special advantage is also to be found in it hen that by choosing a special eccentric precisely defined spreading can be achieved that is present when the eccentric spacer element is off its position of the smallest diameter in the bottom sition of the largest diameter is twisted. To this Way is a precise control of the degree of spreading possible.  

For example, it is advantageous if the distance element ment a cross-section of an ellipse or one in egg ner direction compressed circle, so one to two perpendicular planes is mirror-symmetrical body.

The construction of such an intervertebral implant is particularly easy if the distance element ment between the poor only through his attachment to the Inside of the arms is guided. A special Storage is therefore unnecessary.

The spacer can ver in the longitudinal direction of the arms be slidable, so that after inserting the Zwi intervertebral implant inserted between the arms can be and only then is twisted.

The spacer element preferably has a stop on, the insertion depth of the spacer between arms limited.

For example, the stop may take the form of an one end of the spacer protruding laterally Have flange, which preferably have a circular shape can.

In another embodiment it can be provided that the spacer in the longitudinal direction of the arms interlocking projections and recesses on the Di stamping element on the one hand and on the arms on the other  is set. The spacer is then free rotatable, but cannot in the longitudinal direction of the arms be removed from its position.

A special design of this projection and return ge is obtained when the arms jump back Have the shape of a groove-shaped receiving recess, in which be the spacer with one of its outer surface immerses adjacent edge area. In this case bil So the edge areas of the spacer itself Projections that are in the recess in the form of a nutför Immerse yourself in the recess.

The outer surface of the spacer is at a be preferred embodiment smooth, so that the spacer element easily in the axial direction can be inserted between the arms.

It can further be provided that the distance element ment a non-circular opening or recess for receiving of a turning tool.

It is favorable if the spacer element is in the longitudinal direction direction of the arms only over a small part of the arm length, for example over 10 to 20% of the Overall length. This will make the interior of the intermediate vertebral implant not met by the spacer, there is space for bone material.

In a particularly preferred embodiment provided that the arms have a concave bearing surface  have their inside, which are located on the distance element ment supports.

This contact surface preferably has a recessed one Middle area so that the eccentric distance element ment when immersed in this deepened central area comes into a stable position from which the spacer element only by spreading your arms out again can be rotated.

It is beneficial if the deepened middle area is limited by steps.

The contact surface can be attached at the end of extensions arranges itself that is from the poor inward in Rich extension to the other arm.

It is particularly advantageous if the extensions stanchions are arranged at the free end of the two arms. The extensions then form with the one between them included spacer an end limit for the interior of the implant, the Di stamping element simultaneously forms an end face Sealing plug for this interior.

It is beneficial if the arms are stretched lengthways have extending openings through which a kno Chen growth into the interior of the implant is possible.  

Openings can also be made laterally between the arms be arranged in the space between the arms to lead.

In a particularly preferred embodiment provided that the arms are two parallel to each other the extending webs include one between them Form breakthrough. In this way, the Im plantate four evenly distributed over the circumference, narrow bars, two of which form an arm and together from the spacer in one or spread in the other direction.

The implant can have a circular cross overall have cut, but it is also possible to others To use cross sections, for example a four square cross section, especially a square one Cross-section.

In a further embodiment can be provided be that the implant has a square at one end Cross section and a circle at the other end shaped cross section. The cross-section can change between the square and the circular cross cut continuously along the entire length of the Im change plantates, but it is also possible that these Change occurs abruptly.

It is favorable if an opening is made in the bridge is arranged. This opening can be used to fill the Serve interior with bone material and the other  to carry out a turning tool with its help the Di located at the distal end of the implant stamping element can be rotated.

A plug can be inserted into the opening his.

It is favorable if the arms are on the outside in front carry jumps that extend into the neighboring vertebrae by digging in, this will secure the Intervertebral implant between the two neighboring beard vertebrae ensured.

The following description of preferred embodiment forms of the invention is used in connection with the Drawing of the detailed explanation. Show it:

Fig. 1: a longitudinal sectional view through a inter mediate vertebral implant between two vertebral implant before spreading on;

Fig. 2 is a sectional view taken along line 2-2 in Fig. 1;

Fig. 3: a view similar to Figure 1 after spreading the intervertebral implant tates;

Fig. 4 is a sectional view taken along line 4-4 in Fig. 3;

. FIG. 5 is a view similar to Figure 4 with an intervertebral implant according kreisförmi cross-section;

Fig. 6 is a sectional view taken along line 6-6 in Fig. 5;

FIG. 7 shows a modified embodiment of a management a side view of the intervertebral implant similar to that of Figure 1 with a fixed in the longitudinal direction of the implant Distanzele;.

FIG. 8: a view of the intervertebral implant of FIG. 7 in the direction of the arrow A in FIG. 7;

FIG. 9: a view of a modified exemplary embodiment of an intervertebral implant similar to that of FIG. 5 with a square cross section at one end and a circular cross section at the other end;

Fig. 10 is a sectional view taken along line 10-10 in Fig. 9 and

Fig. 11 is a view of a modified example of imple mentation of an intervertebral implant similar to that of Fig. 5 with a quadrangular external cross-section in the area of spacer side end.

The implant 1 shown in the drawing is an intervertebral implant that is inserted into the space 2 between two adjacent vertebral bodies 3 , 4 and replaces the removed intervertebral disc there. In the embodiment shown in FIGS. 1 to 4, this implant 1 has a square cross section and is laterally delimited by four narrow webs 5 arranged at the corners of the implant 1 , which extend parallel to one another over the entire length of the implant 1 and which are connected at one end to a common end plate 6 . The end plate 6 , which has a central opening 7 with an internal thread 8 , thus delimits the interior of the implant 1 defined by the webs 5 at one end.

On the opposite side, two ne adjacent webs 5 are connected to an inwardly directed wall part 9 , which face each other so that they limit the interior of the same on the other side of the implant 1 . In this way, two of the webs 5 are paired to a lower or an upper arm 10 or 11 , the between the two webs 5 of such an arm is a wide, practically over the entire length of the implant opening 12th , and the interior of the implant 1 is also open to the side over the entire length, as can be clearly seen from the illustration in FIGS. 1 and 3.

The opposite end edges 13 of the wall parts 9 have an arcuate, concave configuration on, so that between them when arms 10 , 11 are not spread open, an oval recess 14 is formed, as is evident from the illustration in FIG. 2. In the central region of the recess 14 , the two end edges 13 have a depression 15 , which is delimited on both sides by a step 16 of low height, which can also be clearly seen from the illustration in FIGS. 2 and 4.

In the recess 14 , a disc-shaped spacer 17 is inserted from the outside, the cross section of which is elliptical or corresponds to a compressed circle, ie the spacer is eccentrically formed with an outer surface 18 which has different diameters in mutually perpendicular directions. The cross-sectional shape of the spacer element 17 is selected so that it can be easily inserted into the recess 14 of the non-spread arms 10 and 11 in one orientation, the insertion depth is limited by an impact in the form of a plate-shaped circumferential element at one end of the spacer element 17 Flange 19 with a circular cross section.

The spacer element 17 has a longitudinal slot 20 into which an only schematically in phantom in FIGS. 1 and 3 shown rotary tool 21 inserted leads may be, the spacing element is rotatable about an axis of rotation with the aid of 17 to the arms 10 in parallel and 11 runs centrally through the implant 1 ver. The spacer 17 is guided between the end edges 13 , and when the spacer 17 is rotated, the two end edges 13 of the wall parts 9 are separated from one another due to the eccentric design of the spacer 17 , as can be seen from the illustration in FIG. 4. This leads to a spreading of the two arms 10 and 11 , the outer sides of which bear against the adjacent vertebral bodies 3 and 4 and thereby push them apart and, if necessary, also tilt them against one another, as is shown schematically in the illustration in FIG. 3. It should be borne in mind that the eccentricity of the spacer 17 and the expansion of the implant through the spreading of the arms 10 and 11 in the drawing for the sake of clarity are shown as exaggerated ben.

If you rotate the spacer 17 by 90 °, it snaps into the recess 15 and can be removed from this win cell position only by further widening of the arms 10 and 11 , so that a maximum is obtained in the angular position shown in FIG. 4 On expansion and at the same time a stable position of the distance element.

The surgeon has through the suitable choice of the spacer element 17 the opportunity to bring about different spreads, just a quarter of a turn of the spacer element, this maximum expansion can be achieved in a defined manner.

The spacer 17 closes the recess 14 between the two wall parts 9 and thus closes the interior of the implant 1 on the side opposite the end plate 6 , the opening 7 in the end plate 6 is usually also closed after filling the inner space with bone material, for example by means of a plug, not shown in the drawing, which is screwed into the internal thread 8 .

In the embodiment of FIGS. 5 and 6, a very similar structure is chosen, which differs essentially only from that of FIGS. 1 to 4 in that the implant has a circular cross section.

In this embodiment, the implant carries in the area of the end plate 6 an external thread 22 , on which a cover plate can optionally be screwed on.

In addition, in this embodiment on the outside of the arms 10 and 11 projections 23 are indicated, which dig into the material of the adjacent vertebral bodies 3 and 4 when the arms 10 and 11 are spread apart and thereby fix the implant in its position once reached. Such projections can of course also be used in the exemplary embodiment of FIGS. 1 to 4.

FIGS. 7 and 8 show a further preferred exemplary embodiment of an intervertebral implant, which largely corresponds to that of FIGS. 1 to 4. Corresponding parts therefore have the same reference numerals.

In contrast to the exemplary embodiment of FIGS. 1 to 4, the spacer element 17 lacks a radially projecting flange 9 , and the spacer element 17 is relatively short in the longitudinal direction of the arms, ie in the axial direction.

In the front edges 13 of the two wall parts 9 are par allel to these front edges 13 extending groove-shaped recesses 24 are incorporated, the width, i.e. the extension in the longitudinal direction of the arms, is slightly larger than the extension of the spacer 17 in the axial direction. The spacer 17 plunges into these recesses 24 and is supported with its outer surface at the bottom of these recesses 24 , so that when the eccentric spacer 17 is rotated, the arms are spread out in the manner described. By immersing in the groove-shaped recess 24 , however, the spacer 17 is secured against displacement in the axial direction in both directions.

In FIGS. 9 to 11 are examples of modified execution intervertebral implants shown, therefore, the extent of the intervertebral implant of Fig. 5 and 6 correspond, corresponding parts bear the same reference numerals.

While in the embodiment of FIGS. 1 to 4 the implant has a square cross section over the entire length, in the implant of FIGS. 5 and 6 a circular cross section extending over the entire length is realized.

In the exemplary embodiments of FIGS. 9 to 11, however, the intervertebral implant has a square cross section at one end and a circular cross section at the other end. For example, in the exemplary embodiment in FIGS. 9 and 10, the end of the implant facing away from the spacer element 17 is square, in particular square, while the implant has a circular cross section in the region close to the spacer element. In the implant of FIG. 11, however, the configuration is exactly the opposite, here the implant has a square, in particular quadratic, cross section at the end of the distance-side element, but a circular cross section at the opposite end.

Claims (26)

1. Intervertebral implant with two arms running essentially parallel to one another, which form support surfaces for adjacent vertebral bodies on their outer sides, with a bridge connecting the arms at one end of the arms and with a bridge engaging between the arms at the other end and depending on its positioning between them the arms more or less spreading spacer element, characterized in that the spacer element ( 17 ) is an eccentric element which is rotatable about an axis of rotation running parallel to the arms ( 10 , 11 ) between the arms ( 10 , 11 ) in this way that its eccentric outer surface ( 18 ) lies against the inside of the arms ( 10 , 11 ) and depending on the angular position of the spacer element ( 17 ) the arms ( 10 , 11 ) spread more or less. 2. Implant according to claim 1, characterized in that the spacer element ( 17 ) has a cross section of an ellipse or a circle compressed in a direction Rich. 3. The implant according to claim 1 or 2, characterized in that the spacer element (17) is rotationally guided only by its engagement with the inner sides of the arms (10, 11) between the arms (10, 11). 4. Implant according to one of the preceding and workman surface, characterized in that the distance element ( 17 ) can be pushed in the longitudinal direction of the arms ( 10 , 11 ). 5. The implant according to claim 4, characterized net gekennzeich that the spacer element (17) has a stop (19), the immersion depth of the spacer element (17) between the arms (10, 11) be excluded. 6. Implant according to claim 5, characterized in that the stop ( 19 ) has the shape of a laterally projecting flange at one end of the spacer element ( 17 ). 7. Implant according to claim 6, characterized net that the flange has a circular shape.   8. The implant according to one of claims 1 to 3, as by in that the spacer element (17) in the longitudinal direction of the arms (10, 11) element by ineinan dergreifende projections and recesses on the spacer (17) on the one hand and on the arms ( 10 , 11 ) on the other hand. 9. Implant according to claim 8, characterized in that the arms ( 10 , 11 ) have a recess in the form of a groove-shaped receiving recess ( 24 ) into which the spacer element ( 17 ) dips with its outer surface adjacent edge area. 10. Implant according to one of the preceding claims, characterized in that the outer surface ( 18 ) of the spacer element ( 17 ) is smooth. 11. Implant according to one of the preceding claims, characterized in that the distance element ( 17 ) has a non-circular opening or recess ( 20 ) for receiving a turning tool ( 21 ). 12. Implant according to one of the preceding claims, characterized in that the punching element ( 17 ) extends in the longitudinal direction of the arms ( 10 , 11 ) only over a small part of the arm length. 13. Implant according to one of the preceding claims, characterized in that the arms ( 10 , 11 ) have a concave contact surface ( 13 ) on their inside, which is supported on the spacer element ( 17 ). 14. Implant according to claim 13, characterized in that the contact surface ( 13 ) has a recessed central region ( 15 ). 15. Implant according to claim 14, characterized in that the recessed central region ( 15 ) is delimited by steps ( 16 ). 16. Implant according to one of claims 13 to 15, characterized in that the contact surface ( 13 ) at the end of extensions ( 9 ) is arranged, which extends from the arms ( 10 , 11 ) inwards towards the other arm ( 11 , 10 ) he stretch. 17. Implant according to claim 16, characterized in that the extensions ( 9 ) at the free end of the two arms ( 10 , 11 ) are arranged. 18. Implant according to one of the preceding claims, characterized in that the arms ( 10 , 11 ) have openings ( 12 ) extending in the longitudinal direction. 19. Implant according to one of the preceding claims, characterized in that openings are arranged laterally between the arms ( 10 , 11 ) which lead into the space between the arms ( 10 , 11 ). 20. Implant according to claim 18 or 19, characterized in that the arms ( 10 , 11 ) each comprise two webs ( 5 ) which run parallel to one another and form an opening ( 12 ) between them. 21. Implant according to one of the preceding claims che, characterized in that it is total has a circular cross section.   22. Implant according to one of claims 1 to 20, there characterized by that it is a square Has cross-section. 23. Implant according to one of claims 1 to 20, there characterized in that there is one at one end has quadrangular cross-section and on the other End a circular cross section. 24. Implant according to one of the preceding claims, characterized in that an opening ( 7 ) is arranged in the bridge ( 6 ). 25. Implant according to claim 24, characterized in that a plug can be inserted into the opening ( 7 ). 26. Implant according to one of the preceding claims, characterized in that the arms ( 10 , 11 ) carry on their outside projections ( 23 ) which dig into the adjacent vertebral bodies ( 3 , 4 ).