WO2009092907A2

WO2009092907A2 - Intervertebral disc prosthesis

Info

Publication number: WO2009092907A2
Application number: PCT/FR2008/001551
Authority: WO
Inventors: Jacques Damm
Original assignee: H.P.I
Priority date: 2007-11-05
Filing date: 2008-11-04
Publication date: 2009-07-30
Also published as: WO2009092907A3; FR2923157A1; FR2923157B1

Abstract

Intervertebral disc prosthesis (1) composed of two prosthesis elements (2, 3), namely an upper prosthesis element (2) and a lower prosthesis element (3), the upper prosthesis element (2) comprising a horizontal upper plate (20), while the lower element (3) comprises a horizontal lower plate (30), said prosthesis being characterized in that the upper element (2), and more particularly its upper plate (20), is directly in contact via its lower face (22) with the lower element (3), and more particularly with the upper face (32) of this lower element, and this without any intermediate component, while the two prosthesis elements (2, 3), and more particularly their respective plates (20, 30), interact through cooperation of shapes, allowing each of the prosthesis elements to move relative to the other prosthesis element by at least pivoting about a vertical axis, characterized in that the upper plate (20) comprises on its lower face (22) a concave hollow profile forming a substantially spherical dish or a convex and substantially spherical protruding profile, while the lower plate (30) comprises on its upper face (32) a concave and substantially spherical hollow profile or a convex protruding profile in order to cooperate with the corresponding profile of the upper element, while the concave hollow profile has a radius of curvature greater than the radius of curvature of the protruding profile.

Description

PROSTHESIS OF INTERVERTEBRAL DISCS

The present invention relates to a disc prosthesis used in spinal surgery. It relates more particularly to a prosthesis intended to replace an intervertebral disc in order to replace it in case of deterioration of the latter.

The vertebral column is a particularly sophisticated but delicate bone architecture that is subjected to numerous efforts that for some individuals end up damaging at least one disc and many people suffer from pain due to the deterioration of one or more intervertebral disc (s). (to the). The intervertebral discs consist of cartilaginous tissue, joining the vertebrae and acting as a shock absorber. For people with one or more disks damaged, the pain is intense and permanent, see disabling, especially when the collapse of the disc nerves are damaged. It is therefore necessary and indispensable to perform an appropriate surgery.

Today's solutions are either graft-filled cages that promote vertebral fusion, or disc replacement prostheses consisting of three parts, two metal parts, and an intermediate plastic part such as polyethylene. The metal used is stainless steel incompatible with MRI (radiological control mask). The polyethylene intermediate may cause harmful debris. The implant must therefore be placed with extreme surgical precision under a risk of migration and dislocation and therefore risk for the unfortunate patient.

The present invention aims to solve the disadvantages of existing prostheses, and proposes a new prosthesis particularly simple. The prosthesis of the invention is composed of two elements therefore easier to install and of course ensures good stability after installation, while the two elements cooperate together by cooperation forms allowing all natural movements of pivoting and tilting. Each of the elements of the prosthesis is advantageously attached to a vertebral body by means of fixing screws. We note also that the face in contact with the corresponding vertebra includes a succession of projections thus ensuring good adhesion.

Thus, the intervertebral disc prosthesis of the invention is composed of two prosthesis elements, namely an upper prosthesis element and a lower prosthesis element, the upper prosthesis element comprising a horizontal upper plate, while the element lower part comprises a horizontal lower plate, said prosthesis being characterized in that the upper element and more particularly its upper plate is directly in contact with its lower face with the lower element and more particularly with the upper face of this lower element and this without an intermediate piece, while the two prosthesis elements and more particularly their respective plate cooperate together by cooperation of forms allowing each of the prosthesis elements to move relative to the other prosthesis element by at least pivoting around a vertical axis, characterized in that the flat upper water comprises on its underside a concave hollow profile forming a substantially spherical bowl or a substantially spherical convex projection profile while the lower plate comprises on its upper face a substantially spherical concave hollow profile or a convex protruding profile in order to cooperate with the corresponding profile of the upper element, while the concave recessed profile has a radius of curvature greater than the radius of curvature of the protruding profile.

According to a complementary feature, each of the elements comprises a retaining lug comprising a hole intended to receive a fixing screw intended to be screwed into the corresponding vertebra so as to retain the prosthesis element with respect to the latter.

According to another feature, the axis of the hole of the retaining tab of the upper element is not disposed vertically to the hole of the retaining tab of the lower element.

Let us add that each of the retaining tabs is in the form of a longitudinal bar which is constituted by an extension of the corresponding plate, said extension extending substantially to the bracket in relation to the general plane of the tray, to extend upward for the upper element, and downward for the lower element.

Note also that the general vertical axis of the retaining tab of the upper element is shifted to the right relative to the vertical plane of general symmetry of the upper plate, while the general vertical axis of the retaining tab of the lower element is shifted to the left with respect to the vertical plane of general symmetry of the lower plate.

It will be added that according to the preferred embodiment, the planes respectively of the retaining tab of the upper element of the retaining tab of the lower element, are not perpendicular to the plane, so the planes are converging towards the outside, while the planes respectively of the retaining tab of the upper element (2) and the retaining tab of the lower element, are not perpendicular to the general plane of each of the respective trays. Thus, the plane of the tab of the upper retaining element forms with the general plane of the upper plate, an acute angle, while the plane of the leg of the lower element forms with the general plane of the lower plate an obtuse angle .

According to a complementary characteristic of the preferred embodiment, the upper face of the upper plate and the lower face of the lower plate are curved, while they comprise a succession of projecting profiles.

Advantageously, the elements of the prosthesis are made of biocompatible material and transparent radio, such as polyetheretherketone (PEEK).

Other features and advantages of the invention will become apparent from the description which follows with reference to the accompanying drawings which are given by way of non-limiting examples.

Figure 1 is an exploded perspective view.

Figure 2 is a side view.

Figure 3 is an end view. Figure 4 is a top view.

Figures 5a and 5b are views showing the upper element

Figure 5a is a view from above;

Figure 5b is a sectional view along A-A

Figures 6a and 6b are views showing the lower element

Figure 6a is a bottom view;

Figure 6b is a sectional view along B-B;

Figure 7 is a sectional view of the prosthesis along C-C;

The disk prosthesis of the invention bearing the general reference (1) is composed of two prosthesis elements (2, 3), namely an upper prosthesis element (2) and a lower prosthesis element (3), the together having a central vertical plane substantially of general symmetry (P).

According to one characteristic of the invention, the two prosthesis elements (2, 3) cooperate together by cooperation of shapes allowing each of the prosthesis elements to move relative to the other prosthesis element by at least free pivoting around a vertical axis (X, X '), and swing sideways in all directions and move laterally from left to right, and forward and backward by lateral slip without there being a stop or allows accordingly any combined movement of the two adjacent vertebrae, thus ensuring a perfect mobility of the column

The upper prosthesis element (2) comprises a horizontal plate (20) which will be called top plate.

The upper plate (20) comprises on its upper face (21) a succession of projecting profiles (210) while its lower face (22) comprises a concave profile (220) forming a spherical bowl having the shape of a portion of sphere to cooperate with a corresponding projecting profile, made in the lower element (3). The lower prosthesis element (3) also comprises a horizontal plate (30) which will be called bottom plate.

The lower plate (30) comprises on its lower face (31) a succession of protruding profiles (310) while its upper face (32) comprises a convex profile (320) of substantially spherical shape in order to cooperate with the recessed profile. corresponding concave (220) made in the upper element (2).

Note that the shape of concave recessed profile (220) is in shape cooperation with the protruding profile (320) so as to allow in the position of use a perfect mobility of one of the elements relative to the other, therefore one vertebra with respect to the other.

For this purpose the concave hollow profile (210) of the upper element (2) is a radius sphere portion (R2) while the convex projection profile (310) of the lower element (3) is a portion sphere whose radius (R3) is smaller than the radius (R2) of the hollow profile (210) of the upper element (2). Thanks to this configuration of cooperation between the lower element and the upper element as described above, the movement of patella and displacement in all directions allows the prosthesis to ensure the physiological movements of the vertebrae, both in rotation 'tilting. Thus, the prosthesis of the invention is such that each of the elements (2, 3) can move relative to the other element by at least free pivoting about a vertical axis (X, X '), and swing by pivoting lateral in all directions and move laterally from left to right, and forward and backward without there being a stop point or allows accordingly any relative combined movement of the two adjacent vertebrae.

According to the illustrated embodiment it is the upper element which has the recessed profile and the lower element which has the protruding profile, but it could be otherwise. Indeed the upper element could have the projecting profile and the lower element would then include the hollow profile.

Moreover, each of the elements (2, 3) comprises a retaining tab (23, 33) comprising a hole (T2, T3) intended to receive a screw of fixation (V) intended to be screwed into the corresponding vertebra in order to retain the prosthesis element relative to the latter.

Each of the retaining tabs (23, 33) is in the form of a longitudinal bar which is constituted by an extension of the corresponding plate, said extension (23, 33) extending substantially at right angles to the general plane of the tray, to extend upwards for the upper element (2), and downwards for the lower element (3).

Moreover, the general vertical axis (V2-V2) of the retaining tab (23) of the upper element (2) is shifted to the right with respect to the vertical plane (P2) of general symmetry of the upper plate (20) .

Note also that the plans respectively (T2) of the retaining tab (23) of the upper element (2) and (T3) of the retaining tab (23) of the lower element (3), are not perpendicular to the plane (P). Thus, the planes (T2) and (T3) are converging towards the outside (EX). Thus, the axes of the vertebral fixation screws are convergent towards the inside (IN), thus ensuring a good upright restraint.

It will be added that the respective planes (T2) of the retaining tab (23) of the upper element (2) and (T3) of the retaining tab (23) of the lower element (2) are not perpendicular. in the general plane (P2, P3) of each of the respective trays (20, 30). Thus, the plane (T2) forms with the general plane (P2) of the upper plate (20) an acute angle (A2), while the plane (T3) forms with the general plane (P3) of the lower plate (30) a obtuse angle (A3). This configuration allows the prosthesis a perfect adaptation to the geometry of the column.

Similarly, the general vertical axis (V3-V3) of the retaining tab (33) of the lower element (3) is shifted to the left with respect to the vertical plane (P3) of general symmetry of the lower plate (30). ).

These lateral offsets are provided so that the axis of the hole (T2) of the upper element (2) to the retaining tab is not disposed vertically to the axis of the hole (T3) of the tab holds the lower element (3). It will also be noted that the upper face (21) of the upper plate (20) is curved. Similarly, the lower face (31) of the lower plate (31) is also curved.

The assembly constituted by the two plates (20, 30) is intended to be engaged between two adjacent vertebrae in place of the degraded disk, while the surgeon connects each of the fixing lugs to the corresponding vertebra by screwing the screw of fixation (V) after having been engaged in the corresponding hole (T2, T3).

Note that each plate (2, 3) in the general shape of a disk to be in a peripheral geometry relationship with the vertebral body of the vertebrae with which they are in contact.

Let us add, and we have understood, from reading the above, that the upper element (2) and more particularly its upper plate (20) is directly in contact with its lower face (22) with the lower element (3). ) and more particularly with the upper face (32) of this lower element and without intermediate piece.

It is also understood from the foregoing that the upper face (21) of the upper plate (20) is in contact with the vertebral body of the adjacent vertebra, and the succession of projections makes it possible to obtain a good grip with said vertebral body. . Similarly, the lower face (31) of the lower plate (30) is in contact with the vertebral body of the adjacent vertebra, and the succession of projections makes it possible to obtain a good grip with said vertebral body. It will be noted that the projections advantageously have a triangular profile and extend transversely with respect to the plane (P).

The successions of projections are in the illustrated example, a succession of transverse teeth, but it could be otherwise.

To further improve the attachment of the elements of the prosthesis, independent complementary projections (4) are made for example of titanium, and are impacted in the plates as shown, and to project, relative to the plane successions of projections. According to one characteristic of the invention, the elements (2, 3) of the prosthesis (1) are made of biocompatible material and transparent radio, and for example material such as polyetheretherketone (PEEK). This material is a high performance thermoplastic, especially to wear, to dynamic fatigue.

Of course, the invention is not limited to the embodiment described and shown by way of example, but it also includes all technical equivalents and their combinations.

Claims

1. Prosthesis (1) of intervertebral discs composed of two prosthesis elements (2, 3), namely an upper prosthesis element (2) and a lower prosthesis element (3), the upper prosthesis element (2) comprising a horizontal upper plate (20), while the lower element (3) comprises a horizontal lower plate (30), said prosthesis being characterized in that the upper element (2) and more particularly its upper plate (20) is directly in contact with its lower face (22) with the lower element (3) and more particularly with the upper face (32) of this lower element and without any intermediate part, while the two prosthesis elements (2, 3 ) and more particularly their respective plate (20, 30) cooperate together by cooperation of forms allowing each of the prosthesis elements to move relative to the other prosthesis element by at least pivoting around a vertical axis (X, X '), characterized in that the upper plate (20) comprises on its lower face (22) a concave hollow profile (220) forming a substantially spherical bowl or a protruding profile (320 ) convex substantially spherical while the lower plate (30) comprises on its upper face (32) a concave hollow profile (320) substantially spherical or a convex projection profile (220) to cooperate with the corresponding profile of the element upper, while the concave recessed profile (210) has a radius of curvature (R2) greater than the radius of curvature of the profile of the protruding profile (230).

2. Prosthesis (1) according to the preceding claim, characterized in that each of the elements (2, 3) comprises a retaining tab (23, 33) comprising a hole (T2, T3) for receiving a fixing screw (V) intended to be screwed into the corresponding vertebra to retain the prosthesis element relative to the latter.

3. Prosthesis (1) according to the preceding claim, characterized in that the axis of the hole (T2) of the retaining lug of the upper element, is not disposed vertically to the hole (T3) of the leg retaining the lower element (3).

4. Prosthesis (1) according to the preceding claim, characterized in that each of the retaining lugs (23, 33) is in the form of a longitudinal bar which is constituted by an extension of the corresponding plate, said extension (23, 33) extending substantially square to the general plane of the tray, to extend upwardly for the upper member (2), and downwardly for the lower member (3).

5. Prosthesis (1) according to the preceding claim, characterized in that also the general vertical axis (V2-V2) of the retaining tab (23) of the upper element (2) is shifted to the right relative in the vertical plane (P2) of general symmetry of the upper plate (20), while the general vertical axis (V3-V3) of the retaining tab (33) of the lower element (3) is shifted to the left by relative to the vertical plane (P3) of general symmetry of the lower plate (30).

6. Prosthesis (1) according to the preceding claim, characterized in that the planes respectively (T2) of the retaining tab (23) of the upper member (2) and (T3) of the retaining tab (23). of the lower element (3), are not perpendicular to the plane (P), thus, the planes (T2) and (T3) are converging towards the outside (EX).

7. Prosthesis (1) according to the preceding claim, characterized in that the planes respectively (T2) of the retaining lug (23) of the upper element (2) and (T3) of the retaining tab (23). of the lower element (2), are not perpendicular to the general plane (P2, P3) of each of the respective plates (20, 30). Thus, the plane (T2) forms with the general plane (P2) of the upper plate (20) an acute angle (A2), while the plane (T3) forms with the general plane (P3) of the lower plate (30) a obtuse angle (A3).

8. Prosthesis (1) according to any one of the preceding claims, characterized in that the upper face (21) of the upper plate (20) and the lower face (31) of the lower plate (31) are curved.

9. Prosthesis (1) according to the preceding claim, characterized in that the upper plate (20) comprises on its upper face (21) a succession protruding profiles (210), while the lower plate (30) comprises on its underside (31) a succession of projecting profiles (310).

10. Prosthesis (1) according to any one of the preceding claims, characterized in that each of the plates (2, 3) to the general shape of a disc to be in a peripheral geometry relationship with the vertebral body of the vertebrae with which they are in contact.

11. Prosthesis (1) according to any one of the preceding claims, characterized in that the elements (2, 3) of the prosthesis (1) are made of biocompatible material and transparent radio.

12. Prosthesis (1) according to the preceding claim, characterized in that the material in which the elements of said prosthesis are made is polyetheretherketone (PEEK).