Intraosseous stent

Abstract

The invention relates to a self-expanding intraosseous stent (100) intended to contain intraosseous cement, characterized in that the stent comprises a central part (101) and two lateral parts (102, 103) arranged on either side of the central part and extending along the same longitudinal axis (X), and in that the central part has a radial force lower than the radial force of the lateral parts.

Claims

1. A self-expanding intraosseous stent intended to contain intraosseous cement, wherein the stent comprises a central part and two lateral parts arranged on either side of the central part and extending along the same longitudinal axis, and wherein the central part has a radial force lower than a radial force of the lateral parts, the stent comprising a coaxial meshed outer tube and meshed inner tube, the inner tube having a length greater than the length of the outer tube, so that ends of the inner tube protrude from the outer tube forming the central part of said stent, said ends of the inner tube forming the lateral parts of said stent, and wherein a meshing, density of the inner tube is lower than a meshing density of the outer tube.

2. The intraosseous stent according to claim 1, wherein the central part of the stent has a diameter greater than the diameter of the lateral parts of said stent.

3. The intraosseous stent according to claim 1, wherein said stent has a biconical shape.

4. The intraosseous stent according to claim 3, wherein the ends of the biconical stent are reinforced by a metal ring.

5. The intraosseous stent according to claim 1, wherein the lateral parts of the stent are secured on the central part, in particular by welding or meshing entanglement.

6. The intraosseous stent according to claim 1, wherein the inner tube is made of steel, chromium-cobalt alloy, or mixture thereof.

7. The intraosseous stent according to claim 1, wherein the outer tube is made of nickel-titanium alloy (Nitinol).

8. The stent according to claim 1, wherein the inner tube is fixed in translation into the outer tube.

9. The stent according to claim 1, wherein at least the central part of the stent is covered with a leak-proof membrane.

10. The stent according to claim 9, wherein the leak-proof membrane is made of polymer.

11. The stent according to claim 1, wherein a length of the stent is comprised between 40 and 80 mm, and the diameter of the central part of said stent is comprised between 10 and 20 mm.

12. An intraosseous surgical cement injection kit comprising a system for the introduction of a stent into a bone lesion and an intraosseous stent according to claim 1 mounted in said introduction system.

13. The intraosseous surgical cement injection kit according to claim 12, further comprising surgical cement injection means and surgical cement.

Description

(1) The invention will be better understood upon reading the following description and upon examining the accompanying figures. These are presented for illustrative purposes and are not limited to the invention. The figures represent:

(2) FIG. 1: Schematic representation seen from the side (A) and the front (B) of an intraosseous stent according to a first embodiment of the invention;

(3) FIG. 2: Schematic representation seen from the side of an intraosseous stent according to a second embodiment of the invention;

(4) FIG. 3: Schematic representation seen from the side of an intraosseous stent according to a third embodiment of the invention.

(5) FIG. 1 represents an intraosseous stent according to a first embodiment of the invention. The intraosseous stent 10 with a generally biconical shape, is intended to be housed in a bone cavity. The stent 10 comprises a central part 11 and two lateral parts 12, 13 arranged coaxially on either side of the central part 11. The central part 11 has an area 14 of larger diameter D substantially equidistant from the ends 15, 16 of smaller diameter d of the lateral parts 12, 13. The diameter of the stent 10 gradually decreases from the area 14 of larger diameter D up to the ends 15, 16 of smaller diameter d.

(6) The ends 15, 16 of the stent 10 are each reinforced by a metal ring 17, such as a steel ring. These metal rings facilitate the anchoring of the ends 15, 16 of the lateral parts in the bone surrounding the bone cavity in which said stent is intended to expand.

(7) The meshing density of the central part 11 is lower than the meshing density of the lateral parts 12, 13. For example, the dimensions of the patterns forming the meshing are larger at the central part 11 than at the lateral parts 12, 13. More specifically, in the example shown in FIG. 1, the dimensions of the patterns decrease from the area 14 of larger diameter up to the ends 15, 16. Alternatively or additionally, the structural elements providing the patterns and therefore the mesh, are thicker at the lateral parts 12, 13 than at the central part 11. This meshing density which is more significant at the lateral parts 12, 13 contributes to increasing the radial force of said lateral parts 12, 13 compared to the central part 11.

(8) Such a stent 10 can be made for example of Nitinol or chromium-cobalt alloy.

(9) According to the invention, it is possible to cover at least the central part 11, having large meshes, with a leak-proof film (not shown) to reduce the risks of cement leakage between said meshes.

(10) FIG. 2 represents an intraosseous stent according to a second embodiment of the invention. The 100 stent comprises a central part 101, at the ends of which lateral parts 102, 103 are added and fixed. The lateral parts 102, 103 extend coaxially on either side of the central part 101.

(11) In this embodiment, the central part 101 has a diameter D that is substantially constant over the entire length (or larger dimension). Similarly, the lateral parts 102, 103 have a diameter d that is substantially constant over the entire length, the diameter d of the lateral parts 102, 103 being strictly smaller than the diameter D of the central part 101. In the example shown in FIG. 2, the ratio of d/D is approximately equal to .

(12) The lateral parts 102, 103 are fixed to the ends 104, 105 of the central part 101, by any way. As shown in FIG. 2, the ends 104, 105 of the central part 101 are tightened around the lateral parts 102, 103 so as to avoid any risk of cement leakage at the junction between said lateral parts 102, 103 and the central part 101 of the stent 100.

(13) The meshing density of the central part 101 is lower than the meshing density of the lateral parts 102, 103. For example, the dimensions of the patterns forming the meshing are larger at the central part 101 than at the lateral parts 102, 103. Alternatively or additionally, the number of patterns forming the mesh is smaller at the central part 101 than at the lateral parts 102, 103. This meshing density which is more significant at the lateral parts 102, 103 contributes to increasing the radial force of said lateral parts 102, 103 compared to the central part 101.

(14) Such a stent 100 can be made of different materials so as to vary the radial forces. For example, the central part 101 can be made of fine Nitinol fibers and the lateral parts 102, 103 can be made of steel, chromium-cobalt alloy or with thick Nitinol fibers.

(15) When the stent 100 is placed into the bone cavity to be treated, the lateral parts 102, 103 are deployed and anchored into the bone bordering said cavity. The deployment of the central part 101, whose radial force is smaller, is achieved during surgical cement injection into the internal volume of said central part 101. Again, it may be interesting to cover at least the central part 101, having large meshes, with a leak-proof film (not shown) to reduce the risks of cement leakage between said meshes.

(16) FIG. 3 represents an intraosseous stent according to a third embodiment of the invention. The stent 200 comprises an outer tube 201 and an inner tube 202 extending coaxially in the internal volume of the outer tube 201.

(17) A length L of the outer tube 201 is strictly smaller than a length l of the inner tube 202. Thus, the ends 203, 204 of the inner tube 202 extend on either side of the outer tube 201. In this embodiment, the outer tube 201 forms the central part of the stent 200, while the ends 203, 204 of the inner tube 202 form the lateral parts of said stent 200.

(18) In this embodiment, the outer tube 201 has a diameter D that is substantially constant over the entire length L. Similarly, the inner tube 202 has a diameter d that is substantially constant over the entire length l, the diameter d being strictly smaller than the diameter D. In the example shown in FIG. 3, the ratio d/D is approximately equal to .

(19) Advantageously, the ends 203, 204 of the inner tube 201 are secured to the ends 205, 206 of the outer tube 201, by any means, in order to prevent any movement of the inner tube 202 with respect to the outer tube 201.

(20) As shown in FIG. 3, the ends 205, 206 of the outer tube 201 are tightened around the ends 203, 204 of the inner tube 202. Such a tightening allows in particular avoiding the risks of cement leakage at the junction between said lateral parts and the central part of the stent 200.

(21) In this embodiment, the meshing density of the inner tube 202 is lower than the meshing density of the outer tube 201, in order to allow the surgical cement, which will be introduced into the stent through the inner tube 202, to escape from said inner tube 202 and to extend into the internal volume of the outer tube 201. For example, the meshing of the inner tube 202 has patterns of large dimensions. In order to impart a high radial force to the inner tube 202, said inner tube 202 is advantageously made of steel or chromium-cobalt alloy with a large meshing. The outer tube 201, for its part, can be made of fine Nitinol fibers.

(22) When the stent 200 is placed into the bone cavity to be treated, the inner tube 202 is radially deployed and the ends 203, 204 are anchored into the bone bordering said cavity. The deployment of the outer tube 201 is achieved during the surgical cement injection, which flows from the inner tube 202 in the internal volume of the outer tube 201.

(23) Advantageously, the outer tube 201 and the ends 203, 204 of the inner tube 202 are covered with a leak-proof film (not shown) to reduce the risks of cement leakage between the meshes of the tubes.