Patent Application
20100063591
The present invention relates to a vertebral disk prosthesis and a component assembly for the formation of a vertebral disk prosthesis.
A large number of vertebral disk prostheses exist. However, some existing prostheses have the drawback of not restoring the lordosis position of the vertebrae and/or the anatomical movement thereof perfectly. Other existing prostheses have the drawback of not being quickly and easily adaptable to the different situation liable to arise, particularly during the procedure; in this way, the same prosthesis may not be easily adapted to be either a “dynamic” prosthesis, i.e. enabling a movement of the vertebrae with some damping, or a prosthesis free from such damping.
The present invention is intended to remedy such drawbacks.
To this end, the prosthesis according to the invention comprises:
In this way, the prosthesis according to the invention comprises two plates and two rings arranged in the anteroposterior plane, in parallel with each other and at a distance from the median anteroposterior plane of these vertebrae, these rings being elastic and compressible, and being inserted directly between the upper and lower plates.
These rings, in combination with said plates, enable a perfect restoration of the anatomical position of both treated vertebrae and a perfect restoration of the anatomical movement of said vertebrae, with a damping effect of the weight bearing thereon by the overlying vertebra.
In particular, the rings may be made of metal, particularly titanium alloy.
Preferentially, each ring comprising two longitudinal portions, at least one of the longitudinal portions of each ring is rounded in the frontal plane in order to enable a rolling movement on the ring of the plate against which said longitudinal section bears, according to the movement of the overlying vertebra with respect to the underlying vertebra.
The risk of metal particle generation due to friction is thus reduced to a minimum.
Each ring may have, viewed in the plane of the opening thereof, an elliptical shape; alternatively, it may display a plane longitudinal portion, either the lower portion or the upper portion.
According to a possible embodiment of the invention, said first installation means comprise an oval shaped block and said second installation means comprise a corresponding oval opening or cavity.
The installation of a ring on the plate is thus carried out by inserting a block of the plate or the ring in, respectively, a corresponding opening of the ring or the plate.
Preferentially, each block has a projecting peripheral rim at its free end, forming a retention means of the block in the corresponding opening or cavity.
The component assembly according to the invention comprises at least one upper plate, at least one lower plate and at least two rings such as those mentioned above, and at least one intermediate plate with a non-elastic structure, each intermediate plate having a convex rounded side and third installation means on the opposite side thereof, said third installation means being able to cooperate with said first installation means to enable an installation of said intermediate plate on either the upper or lower plate.
This component assembly makes it possible to form either a “dynamic” prosthesis comprising the two rings mentioned above, or a prosthesis with no damping effect comprising said intermediate plate, by simply adapting on one of the plates, either both rings, or the intermediate plate. This component assembly thus makes it possible to obtain a vertebral disk prosthesis perfectly adaptable to the different situations liable to arise, particularly during the procedure.
Preferentially, the component assembly comprises several upper plates and/or lower plates and/or several pairs of elastic rings and/or several intermediate plates of different sizes.
According to a preferred embodiment of the invention, said third installation means consist of a recess or blocks intended to cooperate with, respectively, blocks or corresponding cavities of one of the plates. When the blocks comprise the abovementioned projecting peripheral rim, the corresponding recess(es) comprise corresponding peripheral grooves, formed to enable click and ratchet of said rims together.
The invention will be understood more clearly and other characteristics and advantages will emerge, with reference to the schematic figure appended, representing, as non-limitative examples, several possible embodiments of components of the component assembly according to the invention.
For simplification purposes, the parts or components of an embodiment that are found in an identical or similar manner in another embodiment will be identified by the same numeric references and will not be described again.
This prosthesis 1 comprises an upper plate 2, i.e. intended to be attached to the overlying vertebra 100, two elastic rings 3 and a lower plate 4, i.e. intended to be attached to the underlying vertebra 101.
This prosthesis 1 is formed from a component assembly comprising, in addition to the plates 2 and 4 and the rings 3, an intermediate plate 5.
The plates 2 and 4, the rings 3 and intermediate plate 5 are made of metallic material, particularly titanium alloy.
With reference to
Each ring 3 is elastically compressible along a direction perpendicular to its length.
With reference to
As can be understood with reference to
The rings 3, in combination with these plates 2 and 4, enable a perfect restoration of the anatomical position of both vertebrae 100, 101 and a perfect restoration of the anatomical movement of said vertebrae, with a damping effect of the weight borne thereon by the overlying vertebra 100.
The rounded longitudinal portions 3a, 3b of each ring 3 enable a rolling movement of the plates 2 and 4 (particularly of plate 2) on the ring, according to the movement of the vertebra 100 with respect to the vertebra 101. The respective dimensions of the blocks 23 and the openings 15 are such that a slight angular clearance of the rings 3 is possible in the frontal plane and/or the anteroposterior plane, with respect to the lower plate 4.
The intermediate plate 5 is formed by a metallic material part, particularly made of titanium alloy. This plate 5 displays a convex rounded side 25, intended to cooperate with the plate 2, and a plane opposite side, intended to bear against the plate 4. The plate 5 also comprises a transversal recess 26 opening into said plane face, wherein the base is bordered by a peripheral groove 26a.
This recess 26 is designed such that the plate 5 can be inserted closely on the blocks 23 of the plate 4, until the click and ratchet of the peripheral rims 23a of the blocks 23 in the groove 26a of the recess 26.
The component assembly 2 to 5 is used to form either a “dynamic” prosthesis 1 comprising the two rings 3 mentioned above, or a prosthesis with no damping effect comprising said intermediate plate 5, by means of simple adaptation on the plate 4, either of the two rings 3, or the intermediate plate 5. This component assembly thus makes it possible to obtain a vertebral disk prosthesis perfectly adaptable to the different situations liable to occur, particularly during the procedure.
As can be seen from the above description, the invention provides a vertebral disk prosthesis and a component assembly for the formation of a vertebral disk prosthesis with the following decisive advantages:
It goes without saying that the invention is not restricted to the embodiment described above as an example but is extended to any embodiments covered by the claims appended hereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| 06 06504 | Jul 2006 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB07/01978 | 6/29/2007 | WO | 00 | 8/31/2009 |
