Implantable vertebral arthrodesis device for fusing two overlying and underlying vertebrae

Abstract

The present invention relates to an implantable vertebral arthrodesis device (1) for fusing an overlying vertebra and an underlying vertebra, the device comprising an anterior portion (2) having upper and lower bearing zones (2a, 2b) suitable respectively for receiving lower and upper portions (3, 6) of upper and lower laminae (4, 7) of the overlying and underlying vertebrae (5, 8), said zones (2a, 2b) being spaced apart by a minimum height h (h1) for maintaining intervertebral spacing; rigid retaining devices (9) arranged relative to the anterior portion (2) so as to block migration of said anterior portion (2) towards the spinal canal; a posterior portion (10) in connection with said anterior portion (2), including a main housing (11) having first and second openings (11a, 11b) facing each other and suitable for receiving in part the spinous processes (12, 13); and a granular osteosynthesis material arranged in said main housing (11).

Claims

1. An implantable vertebral arthrodesis device for fusing together an underlying vertebra and an overlying vertebra, the device comprising: a) an anterior portion having an upper bearing zone suitable for receiving a lower portion of an upper lamina of the overlying vertebra and a lower bearing zone suitable for receiving an upper portion of a lower lamina of the underlying vertebra, the upper and lower bearing zones being spaced apart by a minimum height h, in order to maintain an intervertebral spacing; b) rigid retaining devices arranged relative to the anterior portion in such a manner as to block migration of said anterior portion towards the spinal canal; c) a posterior portion in connection with said anterior portion, comprising a main housing having first and second openings facing each other and suitable for receiving in part the spinous processes respectively of the underlying and overlying vertebrae; d) a rigid partitioning element arranged between the anterior portion and the posterior portion that co-operates, at least in part with the anterior portion, to define an auxiliary housing having first and second openings facing each other and arranged in such a manner as to be configured to receive in part the laminae of said underlying and overlying vertebrae; and e) granular osteosynthesis material arranged in said main housing and said auxiliary housing.

2. The implantable device according to claim 1, wherein each of the anterior portion, the retaining devices and the partitioning element has a first lateral edge and a second lateral edge, and wherein the main housing is made of a flexible strip having a first end and a second end that are secured respectively to the first lateral edge and to the second lateral edge of said anterior portion and/or of said retaining devices and/or of said partitioning element.

3. The implantable device according to claim 1, wherein the retaining devices are supported by said partitioning element.

4. The implantable device according to claim 1, wherein the retaining devices are supported by said posterior portion.

5. The implantable device according to claim 1, wherein the anterior portion comprises first and second lateral edges in connection with first and second lateral edges of the partitioning element respectively via first and second lateral portions.

6. The implantable device according to claim 5, wherein the first and second lateral portions diverge towards the anterior portion.

7. The implantable device according to claim 1, wherein the partitioning element is generally U-shaped or H-shaped.

8. The implantable device according to claim 1, wherein the upper bearing zone of the anterior portion is convex in shape.

9. The implantable device according to claim 1, wherein the lower bearing zone of the anterior portion is concave in shape.

10. The implantable device according to claim 1, wherein the anterior portion has an anterior face that is concave.

11. The implantable device according to claim 1, wherein the anterior portion slopes towards said partitioning element.

12. The implantable device according to claim 1, wherein the lower bearing zone of the anterior portion comprises first and second feet sloping towards the main housing.

13. The implantable device according to claim 1, wherein each of said partitioning element and said retaining devices has a first lateral edge and a second lateral edge and wherein the retaining devices comprise at least one first upper projection and at least one first lower projection, which projections extend from the first and/or second lateral edge(s) of said partitioning element, and/or of said retaining devices, and are provided at their ends with respective orifices for passing screws.

14. The implantable device according to claim 1, wherein the anterior portion and the retaining devices are made of osteosynthesis material.

15. The implantable device according to claim 14, wherein the posterior portion and the partitioning element are made of osteosynthesis material.

16. A set comprising an implantable device according to claim 1, and a posterior securing device for securing together the upper and lower spinous processes.

17. A set according to claim 16, wherein the posterior securing device comprises an elongate element having first and second ends, and a securing device for securing said ends together.

Description

DETAILED DESCRIPTION OF THE DRAWINGS

(1) The present invention can be better understood on reading about the following three embodiments mentioned in non-limiting manner and described with reference to the following figures, accompanying these presents, in which:

(2) FIGS. 1A and 1B are diagrammatic perspective views of a first embodiment of an implantable device of the invention;

(3) FIG. 2 is a diagrammatic view from beneath of the first embodiment of an implantable device of the invention as shown in FIGS. 1A and 1B;

(4) FIG. 3 is a diagrammatic view seen from above of the first embodiment of an implantable device of the invention as shown in FIGS. 1A, 1B, and 2;

(5) FIG. 4 is a diagrammatic view of a first embodiment of a device of the invention shown in operation in position between overlying and underlying vertebrae, with portions of the device being cut away;

(6) FIG. 5 is a diagrammatic perspective view of a second embodiment of a device of the invention;

(7) FIG. 6 is a diagrammatic perspective view of a first embodiment of a set of the invention comprising the second embodiment of the implantable device as shown in FIG. 5 together with posterior link device linking together the upper and lower spinous processes; and

(8) FIG. 7 is a diagrammatic perspective view of a third embodiment of an implantable device of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

(9) The first embodiment of an implantable vertebra artherodesis device 1 for fusing together two vertebrae, i.e. an overlying vertebra and an underlying vertebra, as shown in FIGS. 1A, 1B, 2, 3, and 4, comprises an anterior portion 2 having a top bearing zone 2a for receiving at least part of the bottom portion 3 of the top lamina 4 of the overlying vertebra 5 and a bottom bearing zone 2b suitable for receiving the top portion 6 of the bottom lamina 7 of the underlying vertebra 8, the top and bottom bearing zones 2a and 2b being spaced apart by a minimum height h1 in order to maintain an intervertebral spacing. The implantable device 1 also has rigid retaining devices 9 arranged relative to the anterior portion 2 so as to block migration of said anterior portion 2 towards the spinal canal.

(10) The implantable device 1 also has a posterior portion 10 in connection with said anterior portion 2, including a main housing 11 having first and second openings 11a and 11b facing each other and suitable for receiving in part the top and bottom spinous processes 12 and 13 respectively of the overlying and underlying vertebrae 5 and 8. At the time of implantation, the main housing 11 is filled with a granular osterosynthesis material (not shown).

(11) In this particular element, the anterior and posterior portions 2 and 10 are rigid.

(12) The implantable device 1 includes a rigid partitioning element 14 arranged between the anterior portion 2 and the posterior portion 10, in particular in a plane that is substantially parallel to the plane in which the anterior portion 2 is arranged.

(13) In this particular element, the retaining devices 9 extend the posterior portion 10 over the anterior portion 2, as can be seen in FIG. 2.

(14) The partitioning element 14 co-operates, at least in part with the anterior portion 2, to define an auxiliary housing 15 having first and second openings 15a and 15b facing each other, said auxiliary housing 15 receiving in operation a granular osteosynthesis material (not shown) and being arranged in such a manner as to receive in part the laminae 4, 7 of said underlying and overlying vertebrae 5 and 8.

(15) The anterior portion 2 has first and second lateral edges 2c and 2d connected to the first and second lateral edges 14c and 14d of the partitioning element 14 via respective first and second lateral portions 16 and 17. Preferably, the first and second lateral portions 16 and 17 diverge towards the anterior portion 2.

(16) The partitioning element 14 is generally U-shaped, as can be seen in FIG. 3. In this particular example, the posterior portion 10, the retaining devices 9, the partitioning element 14, and the posterior portion 2 are a single molded part, e.g. made of PEEK or hydroxyapatite.

(17) The top bearing zone 2a of the anterior portion 2 is convex in shape; preferably the bottom bearing zone 2b of the anterior portion 2 is concave in shape.

(18) The anterior portion 2 has an anterior face 2e that is concave. The anterior portion 2 slopes towards said partitioning element 14, and in particular forms an angle 1 with the bearing plane (P1) on which the implantable device 1 rests, where 1 is less than 90°, preferably lying in the range 45° to 90°.

(19) The lower bearing zone 2b of the anterior portion 2 has first and second feet 50 and 51 sloping towards the main housing 11.

(20) In operation, granular osteosynthesis material is arranged in the auxiliary and main housings 15 and 11, preferably so as to project from said housings 11 and 15 in order to mitigate the observed 20% shrinkage in volume.

(21) The implantable device 1 then has the anterior portion 2 placed between the laminae 4 and 7 and the posterior portion 10 placed between the upper and lower spinous processes 12 and 13, as shown in FIG. 4. The spinous processes 12 and 13 may optionally be incised, as shown in FIG. 4, so as to penetrate better into said main housing 11 and so as to come into contact with the osteosynthesis material.

(22) The anterior portion 2 serves to adjust intervertebral spacing. The partitioning element 14 improves the stability of the anterior portion 2 and prevents it from tilting towards the spinous processes 12, 13. The areas of contact between the osteosynthesis material and the upper and lower laminae 4 and 7, and between the osteosynthesis material and the upper and lower spinous processes 12 and 13 are large, thereby encouraging bone fusion beyond merely the spinous processes 12, 13.

(23) The second embodiment of the implantable device 18 shown in FIGS. 5 and 6 is described below only for its differences compared with the first embodiment of an implantable device 1. The posterior portion 19 is made of a flexible material, in particular of a flexible strip 20 having a first end 20a and a second end 20b that are secured respectively to the first and second edges 25a and 25b of said partitioning element 25, and also respectively to the first and second lateral portions 21 and 22 connecting the first and second lateral edges 23a and 23b of the anterior portion 23 to the edges 25a and 25b of said partitioning element 25.

(24) The anterior portion 23 serves to maintain vertebral spacing at a height h2 via the upper and lower bearing zones 23c and 23d.

(25) In this example, the retaining devices 24 are supported by the partitioning element 25. The partitioning element 25 and the retaining devices 24 are thus generally U-shaped. The anterior portion 23, the partitioning element 25, and the retaining devices 24 are rigid, and in this particular embodiment they are made as a single part, e.g. by molding PEEK or hydroxyapatite.

(26) In operation, the second embodiment of an implantable device 18 is placed between over- and underlying vertebrae 26 and 27 in the same manner as the first embodiment of an implantable device 1. Since the main housing 28 is made of a flexible material, such as a textile panel, it enables the spinous processes 29, 30 make greater contact with the osteosynthesis material during lordosis movements of the spine, thereby encouraging activation of the bone graft and the formation of bone fusion.

(27) FIG. 6 shows a first embodiment of a set 31 of the invention comprising the implantable device 18 shown in FIG. 5. The set 31 thus comprises a posterior securing device 32 for securing the upper and lower spinous processes 29 and 30 to each other. The posterior securing device 32 comprise an elongate element 33 having first and second ends and a device for securing said ends to each other. Said posterior securing device 32 may be removable, as described in FR 2 961 687 A1. In this particular embodiment, the elongate element 32 surrounds the upper and lower spinous processes 29 and 30 and also the posterior portion 19 containing the granular osteosynthesis material. The elongate element 33 thus contributes to holding the granular osteosynthesis material in the main housing 28, in particular when the spine is in extension.

(28) The third embodiment of an implantable device 34 of the invention is described below only for its differences relative to the first embodiment of an implantable device 1. The third embodiment of an implantable device 34 has a posterior portion 35 and an anterior portion 36 that are both made of flexible material. The anterior portion 36 is made of a flexible strip 38 having first and second ends 38a and 38b that are secured respectively to the first edge 39a and to the second edge 39b of the retaining devices 29. Likewise, the posterior portion 35 is made of a flexible strip 40 having first and second ends 40a and 40b that are secured respectively to the first edge 39a and to the second 39b of the retaining devices 39.

(29) Together, the partitioning element 41 and the retaining devices 39 are generally H-shaped. The retaining devices 39 comprise first and second upper projections 42 and 43 and first and second lower projections 44 and 45 respectively extending the first and second lateral edges 39a and 39b of said retaining devices 39. Each of these projections 42 to 45 is provided with at least one orifice 46 suitable for co-operating with a screw (not shown). Said projections 42 to 45 and the screws thus form posterior securing devices 47 for securing the implantable device 34 to the upper and lower spinous processes.

(30) The provision of an osteosynthesis material in sufficiently compacted manner in the auxiliary housing 48 defined between the anterior portion 36 and the partitioning element 41 enables upper and lower bearing zones 35a and 35b to be formed that are suitable for coming into contact with the upper and lower laminae and thus serves to maintain minimum vertebral spacing, corresponding to the minimum height h2 of the anterior portion 36.

(31) The at least partial deformation of the auxiliary housing 48 serves to improve bone fusion, since the osteosynthesis material is stimulated to a greater extent by the over- and underlying vertebral laminae in the vertebral region that is to be corrected.