KR20050090376A - Intervertebral disk prosthesis or artificial vertebra - Google Patents

Abstract

Disclosed is an intervertebral disk prosthesis comprising an essentially hollow cylindrical base element (1) which is provided with a casing (2) that is embodied as a bellows, a top end (3), a bottom end (4), and a central longitudinal axis (5), an upper apposition plate (6) which is disposed perpendicular to the longitudinal axis (5) at the top end (3) of the base element (1) and rests on the base plate of a vertebra, and a lower apposition plate (7) that is arranged perpendicular to the longitudinal axis (5) at the bottom end (4) of the base element (1) and leans on the cover plate of a vertebra. The casing (2) that is embodied as a bellows is configured as a spring element having a defined spring rate. Said structure largely approaches the function and purpose of a natural intervertebral disk.

Description

Intervertebral disc implants and artificial spine {INTERVERTEBRAL DISK PROSTHESIS OR ARTIFICIAL VERTEBRA}

The present invention relates to an intervertebral disc implant and an artificial spine by the preamble of claim 1.

U.S. Patent No. 4,932,975 to Main et al. Discloses a vertebra prosthesis comprising inflatable bellows as a body. The bellows are made of a flexible material that allows the bellows to expand. However, in the case of such bellows, the handler handles a passive element through which the fluid can be filled, through the opening, and the bellows is manually elongated. Thus, in the case of such known devices, there is no active elastic element capable of elastically absorbing the load. A further disadvantage of known spinal implants is that they must subsequently be refilled with a fluid, such as methacrylate (particularly methylmethacrylate MMA), which poses a significant risk.

1 is a perspective view of an intervertebral disc implant.

FIG. 2 is a plan view of the intervertebral disc implant according to FIG. 2. FIG.

3 is a longitudinal cross-sectional view taken along the line B-B in FIG.

4 is a longitudinal cross-sectional view of the intervertebral disc implant of FIG. 1.

5 is a perspective view of an intervertebral disc implant having a central hole.

FIG. 6 is a plan view of the intervertebral disc implant of FIG. 5. FIG.

7 is a longitudinal cross-sectional view taken along line B-B in FIG. 6.

8 is a partially cut away perspective view of an intervertebral disc implant having two bellows inserted relative to one another.

SUMMARY OF THE INVENTION An object of the present invention is to overcome these problems, and an object of the present invention is to provide an intervertebral disc implant having axially dampening components that absorbs translation, rotation and angulation and delivers it in a predetermined manner. It is to provide artificial spine.

The above object of the present invention is achieved by an intervertebral disc implant and an artificial spine having the features of claim 1.

The advantages essentially obtained by the present invention are that, due to the intervertebral disc implant and the artificial spine of the present invention, the function and task of the intervertebral disc and the original spine can be reproduced most closely.

Other advantageous configurations of the invention are characterized by what is disclosed in the dependent claims.

Each embodiment will be described in most cases based on an intervertebral disc implant; However, all embodiments are also applicable to artificial spine.

The specific spring rate of the spring member is at least 50 N / mm, preferably at least 100 N / mm. However, the spring rate is preferably 150 N / mm, preferably at least 400 N / mm. The upper limit of the spring rate should also be limited, up to 800 N / mm, preferably up to 2000 N / mm. The spring rate is typically 600 N / mm.

If the load is 1000 N, the spring travel of the spring member should be in the range of 1-2 mm, preferably in the range of 1.3-1.7 mm. Spring travel under this load is typically 1.5 mm.

According to one aspect of the invention, the spring member is made of a tension spring and a compression spring.

The number of folds in the jacket consisting of bellows is in the range of 3-10, preferably in the range of 4-5. This number is advantageous in terms of both the manufacturing techniques and the desired stretching of the materials used.

According to one embodiment of the invention, the jacket comprises a plurality of single layers. Therefore, the stiffness of the bellows can be arbitrarily adjusted within a certain range.

In a particular embodiment, the monolayers are spaced apart from each other. This configuration allows the various bellows to be coupled together to accommodate a variety of loads, for example external belllows for angulation, translation, rotation and dampening of the load, for example a load of 800 N and about 2500 N. The inner bellows absorbing will be combined to protect the outer bellows.

In other particular embodiments, the monolayers are adjacent to each other without an interlayer. Thus stiffness can be increased.

In the case of another embodiment, the jacket comprises a plurality of bellows inserted inside each other.

The jacket may basically have slots extending parallel to the longitudinal axis. Because of this, the rotational stiffness of the bellows will be reduced.

The rotational stiffness of the jacket should be chosen to allow for 1 ° -3 ° rotation of the jacket, preferably 1.5 ° -2.5 °.

When using an axial force of 800 N, the axial stroke of the jacket should be in the range 1.0-2.5 mm, preferably in the range 1.30-1.75 mm.

According to one embodiment of the invention, both apposition plates are rigidly but rotatably fixed in the axial direction at the top end and bottom end of the body.

In another embodiment, both parallel plates are axially fixed at the upper and lower ends of the body and their rotation about the longitudinal axis is limited, preferably at an angular range of up to 5 °.

In another embodiment, both parallel plates are rigidly rotatably fixed to the upper and lower ends of the body.

In a particular embodiment, the rotational stiffness of the jacket made of bellows is selected such that both parallel plates can rotate about 1 ° -5 °, preferably 2 ° -3 °, with respect to each other about the longitudinal axis. .

In further embodiments, both plates may be tilted by an angle of 4 ° -8 °, preferably 5 ° -7 °, relative to a plane perpendicular to the longitudinal axis.

In the case of a particular embodiment of the invention, the hollow-cylindrical basic body is filled with a solid body, preferably synthetic material, which at least partly functions as a cushioning material. Due to this configuration, the rigidity is increased and it is possible to absorb larger impact loads (for example, 2500N).

The jacket of the intervertebral disc implant may be made of a metal, such as titanium or a metal alloy, preferably an alloy based on titanium. The material of the jacket preferably has a minimum stretch limit of 30%, more preferably at least 38%. However, the jacket may also be made of synthetic material, preferably elastomer.

In a particular embodiment of the invention, the jacket can be made from a packet of cup springs.

The present invention and its improvements will now be described in detail based on some schematic perspectives of some embodiments.

The intervertebral disc implants shown in FIGS. 1-3 have a hollow-cylindrical basic body 1, a top end 3, a bottom end 4 and a bellows-shaped jacket 2. It essentially includes the central longitudinal axis (5). On the upper end 3 of the body, an upper parallel plate 6 which is adapted to function as a support for the base plate of the vertebral body is mounted transversely about the longitudinal axis 5. On the lower end 4 of the main body 1, a lower parallel plate 7, which can be placed on the cover plate of the vertebral body, is mounted horizontally with respect to the longitudinal axis 5.

Both parallel plates 6, 7 have an outwardly structured surface 8 consisting of a plurality of pyramid teeth, so that they can maintain better contact with the base and cover plates of adjacent vertebral bodies. have. The structured surface 8 may be embodied in the form of etching surfaces or in the form of surface structures that facilitate attachment of bone tissue.

The jacket 2 composed of outer bellows has three to six folds (waves) in total.

The height of the intervertebral disc implant is 5-15 mm, depending on the embodiment, the diameter is in the range of 10-35 mm and the thickness of the jacket is about 0.1 mm.

Both parallel plates 6, 7 may have inward facing axial spigots 12, 13 composed of dampening elements.

In the embodiment shown in FIG. 4, both parallel plates 6, 7 with axial inserts inwardly contacted as bearing inserts are rotatably mounted on the housing 14, but rotation is not shown. can be limited by (stops).

The embodiment of the intervertebral disc implants shown in FIGS. 5 to 7 is constructed similarly to the intervertebral disc implants according to FIGS. 1 to 3. The difference is that both parallel plates 6, 7 consist of annulus, so that a hole 9 penetrating the ring in the axial direction is formed. Another difference is that in this embodiment the jacket 2 consisting of bellows has only one fold (wave).

8 illustrates in detail the operation of the intervertebral disc implant. In the case of this embodiment, the jacket 2 comprises an outer bellows 21 and an inner bellows 22. The outer bellows 21 has five folds and the inner bellows 22 has nine bellows. The outer bellows 21 is fixed on the upper parallel plate 6 and the inner bellows 22 is fixed on the lower parallel plate 7. Depending on the material, the bellows is soldered, caulked or pressed to the parallel plates 5, 6. In the embodiment shown, the bellows 21, 22 are inserted into circular grooves 10, 11 which are mounted inside both parallel plates 6, 7. As shown in FIG. 8, two parallel plates 5, 6, which can be fixed to the bellows 21, 22, can be fitted together to form a box. As a result, the two parallel plates 5, 6 can rotate relative to each other. The rotation, not shown, may limit the rotation to a predetermined value, for example in the range of 2 ° -3 °.

Claims (25)

A) an essentially hollow-cylindrical body 1 comprising a jacket 2 composed of bellows, an upper end 3, a lower end 4 and a central longitudinal axis 5; B) an upper parallel plate 6 for supporting a base plate of the vertebral body, mounted transversely to the longitudinal axis on the upper end 3 of the body 1; C) a lower parallel plate, which can be located on the cover plate of the vertebral body, mounted transversely with respect to the longitudinal axis 5 on the lower end 4 of the body 1, D) Intervertebral disc implant or artificial spine, characterized in that the jacket (2) consisting of bellows is composed of a spring member having a specific spring rate. The intervertebral disc or artificial spine according to claim 1, wherein the special spring rate is at least 50 N / mm, preferably at least 100 N / mm. Intervertebral disc or artificial spine according to claim 2, characterized in that said special spring rate is at least 150 N / mm, preferably at least 400 N / mm. Intervertebral disc or artificial spine according to any one of claims 1 to 3, characterized in that the special spring rate is at most 800 N / mm, preferably at most 2000 N / mm. The intervertebral disc prosthesis according to any one of claims 1 to 4, wherein under a load of 1000 N the spring travel of the spring member is in the range of 1-2 mm, preferably in the range of 1.3-1.7 mm. Artificial spine.  The intervertebral disc implant or artificial spine according to any one of claims 1 to 5, wherein the spring member is a tension spring and a compression spring. The intervertebral disc implant or artificial according to any one of claims 1 to 6, characterized in that the number of folds of the jacket (2) consisting of bellows is in the range of 3-10, preferably in the range of 4-5. spine. Intervertebral disc or artificial spine according to any one of claims 1 to 7, characterized in that the jacket (2) comprises a plurality of single layers. 9. The intervertebral disc implant or artificial spine of claim 8, wherein the monolayers are spaced apart from each other. The intervertebral disc implant or artificial spine of claim 8, wherein the monolayers are adjacent to each other without an intermediate layer. Intervertebral disc implant or artificial spine according to any one of the preceding claims, characterized in that the jacket (2) comprises a plurality of bellows inserted relative to one another. 12. Intervertebral disc implant or artificial spine according to any one of the preceding claims, characterized in that the jacket has slots extending parallel to the longitudinal axis (5). 13. Intervertebral disc prosthesis according to any of the preceding claims, characterized in that the rigidity of the jacket (2) permits a 1 ° -3 ° rotation of the jacket, preferably a 1.5 ° -2.5 ° rotation. Or artificial spine. 14. Intervertebral disc implant according to any one of the preceding claims, characterized in that when an axial force of 800 N is applied, the axial stroke of the jacket is in the range of 1.0-2.5 mm, preferably 1.30-1.75 mm. Or artificial spine. The parallel plate 6, 7, according to claim 1, wherein the parallel plates 6, 7 are axially rigid but rotatably fixed to the upper end 3 and the lower end 4 of the body 1. Intervertebral disc implant or artificial spine. 16. Both of the parallel plates 6, 7 are fixed to the upper end 3 and the lower end 4 of the main body 1, and around their longitudinal axis 5, according to one of the preceding claims. Intervertebral disc prosthesis or artificial spine, characterized in that the rotation of is limited, preferably limited to a range of up to 5 °. 16. The parallel plate 6, 7 of claim 1, wherein both of the parallel plates 6, 7 are rigidly rotatably fixed in the axial direction to the upper end 3 and the lower end 4 of the body 1. Intervertebral disc implant or artificial spine. 18. The rotational rigidity of the jacket (2) consisting of bellows according to claim 17, wherein both parallel plates (6, 7) are 1 ° -5 °, preferably 2 ° -3, about the longitudinal axis (5) with respect to each other. Intervertebral disc implant or artificial spine, characterized in that it is selected to be rotatable by °. The method according to claim 1, wherein both parallel plates 6, 7 are 4 ° -8 °, preferably 5 ° -7 °, with respect to a plane perpendicular to the longitudinal axis 5. Intervertebral disc implant or artificial vertebra, characterized in that it can be tilted. 20. Intervertebral disc implant or artificial spine according to any one of claims 1 to 19, characterized in that the hollow-cylindrical body (1) is at least partially filled with a solid body which functions as a cushioning material. 21. Intervertebral disc implant or artificial spine according to claim 20, characterized in that the solid is a synthetic material, preferably an elastomer. 23. Intervertebral disc prosthesis or artificial spine according to any one of the preceding claims, characterized in that the jacket (2) is made of a metal or a metal alloy, preferably an alloy based on titanium. 23. The intervertebral disc implant or artificial spine according to any one of claims 1 to 22, characterized in that the material of the jacket (2) has a minimum stretch limit of 30%, preferably 38%. 23. Intervertebral disc implant or artificial spine according to any one of the preceding claims, characterized in that the jacket (2) consists of a synthetic material, preferably an elastomer. The intervertebral disc implant or artificial spine according to any one of claims 1 to 24, wherein the jacket (2) consists of a packet of cup springs.