BONE ANCHOR FOR OPTIMISED CEMENT APPLICATION

Abstract

A bone anchor for the fixation of bone components and bone fragments, including a shaft, a neck area and a head located in proximal direction and a tip located in distal direction, wherein the bone anchor has a mainly cylindrically shaped hollow chamber extending along the central axis, wherein the hollow chamber is adjacent a transition zone located proximally from a central plane, characterized in that the transition zone at least partially has an inner diameter and the hollow chamber at least partially has an opening diameter, and the opening diameter of the hollow chamber is greater than the inner diameter of the proximal transition zone.

Claims

1. A bone anchor for the fixation of bone components and bone fragments, comprising a shaft, a neck area and a head located in proximal direction and a tip located in distal direction; wherein the bone anchor has a mainly cylindrically shaped hollow chamber extending along the central axis; wherein the hollow chamber is adjacent a transition zone located proximally from a central plane; the transition zone at least partially has an inner diameter and the hollow chamber at least partially has an opening diameter; and the opening diameter of the hollow chamber is greater than the inner diameter of the proximal transition zone.

2. The bone anchor according to claim 1, characterized in that in the further proximal course along the central axis an opening adjoins the proximal transition zone, which is suitable for receiving a cannula at least in sections.

3. The bone anchor according to claim 1, characterized in that the opening diameter of the opening adjacent to the proximal transition zone is greater than at least one portion of the inner diameter of the proximal transition zone.

4. The bone anchor according to claim 1, characterized in that the opening opens in proximal direction into a tool attachment point.

5. The bone anchor according to claim 1, characterized in that the hollow chamber adjoins a distal transition zone located distally from a central plane, and the distal transition zone has an inner diameter at least in sections, and the hollow chamber has an opening diameter at least in sections, and the opening diameter of the hollow chamber is greater than the inner diameter of the distal transition zone.

6. The bone anchor according to claim 5 characterized in that the transition zone defines a section which causes a higher flow resistance compared to a section of the same length of the hollow chamber.

7. The bone anchor according to claim 5, characterized in that the transition zone defines a section that causes a higher pressure difference in the liquid compared to a section of the same length in the hollow chamber.

8. The bone anchor according to claim 5 characterized in that the transition zone defines a section which leads to a higher internal friction in the liquid compared to a section of the same length of the hollow chamber.

9. The bone anchor according to claim 5, characterized in that the transition zone has a higher surface friction coefficient or a higher surface roughness than the hollow chamber.

10. The bone anchor according to claim 5, characterized in that the transition zone allows a smaller volume flow of liquid than the hollow chamber.

11. The bone anchor according to claim 5, characterized in that the transition zone consists of at least one segment having at least one surface element defining the inner opening diameter and at least one surface element defining a stagnation space, and at least one surface element which generates a dynamic pressure in the blocking direction, in which the surface element is arranged at an angle to an orthogonal of the central axis between −20° and 20°, and this surface element is planar, concave or convexly curved.

12. The bone anchor according to claim 5, characterized in that the transition zone consists of at least one segment having at least one surface element defining a stagnation space, and a ring is arranged in this stagnation space.

13. The bone anchor according to claim 12, characterized in that the ring with the inner side defines the opening diameter of the transition zone.

14. The bone anchor according to claim 12, characterized in that the ring is convexly curved at a radial outside.

15. The bone anchor according to claim 1, characterized in that the transition zone causes at least one difference in the flow resistance, or pressure difference, or internal friction of the liquid, or volume flow, and this difference is dependent on the flow direction of the liquid.

16. The bone anchor according to claim 5, characterized in that the transition zone has a blocking direction and a forward direction for liquids.

17. The bone anchor according to claim 1, characterized in that the hollow chamber, as viewed from a central plane, is distally adjacent to a distal transition zone and proximally adjacent to a proximal transition zone, and the distal transition zone has a forward direction in proximal direction and the proximal transition zone has a forward direction in distal direction.

18. The bone anchor according to claim 1, characterized in that the hollow chamber, as viewed from a central plane, is distally adjacent to a distal transition zone and proximally adjacent to a proximal transition zone, and the distal transition zone has a blocking direction in distal direction and the proximal transition zone has a blocking direction in proximal direction.

19. The bone anchor according to claim 1, characterized in that the hollow chamber has at least one laterally extending opening communicating with the hollow chamber, and in the case of more than one opening, the openings are arranged circumferentially in ring-like formation, and in the case of more than one circumferentially ring-like formation, the openings and have different opening diameters per formation.

20. The bone anchor according to claim 1, characterised in that the bone anchor is formed in one piece.

21. The bone anchor according to claim 1, characterized in that the bone anchor is grooved throughout.

Description

BRIEF DESCRIPTION OF THE DRAWINGS SHOW

[0026] FIG. 1 an oblique view of the bone anchor according to the invention,

[0027] FIG. 2 side view and corresponding sectional view through the bone anchor according to the invention,

[0028] FIG. 3a further sectional view, showing a simplified representation of a fluidic diode,

[0029] FIG. 3b abstract representation of the components relevant to fluid flow,

[0030] FIG. 4a in application of a liquid through a cannula, and

[0031] FIG. 4b immediately after the cannula has been removed.

[0032] FIG. 5a shows a simple form of fluidic diode in the forward direction, and FIG. 5b in the blocking direction.

[0033] FIG. 6a shows the structure of an alternative form of fluidic diode in the forward direction, and FIG. 6b in the blocking direction.

[0034] FIG. 7a illustrates an alternative embodiment of a fluidic diode in forward direction, whereas FIG. 7b illustrates the reverse flow principle.

[0035] FIG. 8 shows a ¾ section in an oblique view from FIG. 7a/b.