SCREW ELEMENT OPTIMIZED FOR 3D PRINTING

Abstract

A screw element for the fixation of bone components and bone fragments is disclosed having a shaft with an external thread and a longitudinal central axis extending along the shaft and defining distal and proximal directions. The screw element includes a continuous cannulation, the cannulation includes at least two laterally extending openings communicating with the cannulation, and that the openings are configured as a polygon in a side view.

Claims

1. A screw element for the fixation of bone components and bone fragments comprising a shaft with an external thread and a longitudinal central axis extending along the shaft and thereby defining a distal and a proximal direction, and the screw element comprises a continuous cannulation, the cannulation comprises at least two laterally extending openings communicating with the cannulation, wherein the openings are configured as a polygon in a side view.

2. The screw element according to the claim 1, wherein the polygon has at least one panel element formed mainly along the central axis.

3. The screw element according to claim 1, wherein the distance between the panel elements extending parallel to the central axis is smaller than the cannulation diameter D82 at the outlet.

4. The screw element according to claim 1, wherein the polygon has at least two panel elements which, in a side view, are each oriented at an angle of from 25° to 65°, with respect to the central axis.

5. The screw element according to claim 1, wherein at least two panel elements are symmetrically oriented with respect to the central axis.

6. The screw element according to claim 1, wherein the panel elements merge into one another with the aid of curves.

7. The screw element according to claim 1, wherein the lateral openings in peripheral direction are positioned in ring-like formation and in case of more than one in peripheral direction ring-like formation, the openings have different opening cross-sectional areas per formation.

8. The screw element according to claim 1, wherein the opening cross-sectional area of the distal formation is larger than the opening cross-sectional area of the proximal formation.

9. The screw element according to claim 1, wherein the lateral openings are positioned in the thread base.

10. The screw element according to claim 1, wherein the screw element additionally comprises a head, a neck area and a shaft area with bone thread and a tool attachment point is provided in the head.

11. The screw element according to claim 1, wherein the tool attachment point is bounded in the distal direction by a wall and said wall extends radially inward as an inclination in increasing distal direction and the cone angle formed by the wall is less than 120°.

12. The screw element according to claim 11, wherein the wall has a substantially right-angled cone angle.

13. The screw element according to claim 1, wherein the tool attachment point is open in proximal direction and opens into a concentric conical recess and has a substantially right-angled cone angle.

14. The screw element according to claim 1, wherein the external thread can be divided into a proximal threaded area adjacent to the neck area and extending in distal direction, and a distal threaded area adjacent thereto, and distal tip area adjacent thereto, and the distal threaded area merges into the proximal threaded area in a transition zone, and the proximal threaded area forms at least one additional thread which forms at least one cutting edge within the transition zone.

15. The screw element according to claim 1, wherein the distal tip area forms at least one cutting edge.

16. The screw element according to claim 14, wherein at least one of the cutting edges is planar and oriented substantially in radial direction.

17. The screw element according to claim 14, wherein at least one of the cutting edges has a concave surface which is oriented mainly in radial direction.

18. The screw element according to claim 14, wherein at least one of the cutting edges has a convex surface which is oriented mainly in radial direction.

19. The screw element according to claim 1, wherein the cannulation has, in proximal direction along the central axis, an at least sectionally cylindrical diameter extension configured to receive a cannula at least sectionally.

20. The screw element according to claim 1, wherein the head area comprises, at least sectionally, a spherical segment configured to provide a polyaxial pivotable connection with a fork head that is u-shaped in a side view.

21. The screw element according to claim 1, wherein the orientation of the screw element corresponds substantially to the direction of the central axis and extends from proximal to distal.

22. The screw element according to claim 1, wherein the external thread of the screw element has at least one surface facing mainly distally and at least one surface facing mainly proximally, and the proximally facing surface has a greater roughness than the distally facing surface.

23. The screw element for the fixation of bone components and bone fragments comprising a shaft with an external thread and a longitudinal central axis extending along the shaft and thereby defining a distal and a proximal direction, and the screw element comprises a continuous cannulation, the cannulation comprises at least two laterally extending openings communicating with the cannulation, wherein the openings are configured as a polygon in a side view, and that the external thread can be divided into a proximal threaded area adjacent to the neck area and extending in distal direction, and a distal threaded area adjacent thereto, and a distal tip area adjacent thereto, and the distal threaded area merges into the proximal threaded area in a transition zone, and the proximal threaded area forms at least one additional thread which forms at least one cutting edge within the transition zone.

24. The screw element for the fixation of bone components and bone fragments comprising a shaft with an external thread and a longitudinal central axis extending along the shaft and thereby defining a distal and a proximal direction and dividing the external thread into a proximal threaded area adjacent to the neck area and extending in distal direction, and a distal threaded area adjacent thereto, and a distal tip area adjacent thereto, and a distal threaded area adjacent thereto, and a distal tip area adjacent thereto, and the distal threaded area merges into the proximal threaded area in a transition zone, wherein the proximal threaded area forms at least one additional thread which forms at least one cutting edge within the transition zone.

Description

BRIEF DESCRIPTION OF THE DRAWINGS SHOW

[0024] FIG. 1 an oblique view of the screw element according to the invention,

[0025] FIG. 2 a side view of the screw element according to the invention and a detailed view of the polygon-shaped lateral openings.

[0026] FIG. 3 side view and corresponding sectional view through the bone anchor according to the invention,

[0027] FIG. 4 two screw elements according to the invention in combination with u-shaped fork heads mounted with a connecting rod.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] FIG. 1 shows the screw element (1) comprising a head area (10), a neck area (20) and a shaft area (11) with bone thread (12). Furthermore, it can be seen that the external thread (12) can be divided into a proximal threaded area (30) adjacent to the neck area (20) and extending in distal direction (102), and a distal threaded area (50) adjacent thereto, and a distal tip area (60) adjacent thereto, and the distal threaded area (50) merges into the proximal threaded area (30) in a transition zone (40), and the proximal threaded area (30) forms at least one additional thread (31, 32) which forms at least one cutting edge (41) within the transition zone (40).

[0029] Another cutting edge (61) is formed at the distal tip area (60). Optimally, the respective cutting edge (41, 61) is mainly planar in radial direction. Other surface geometries with convex or concave areas are also possible. Alternatively, recurring patterns with a pre-cutting effect, such as fluting or teeth, are also possible in the peripheral direction.

[0030] FIG. 1 shows a preferred embodiment of a screw element (1) which forms two separate thread teeth (51 and 52) in the distal area (50). This is a so-called double thread, whereby a larger pitch is achieved with the same number of thread teeth compared to a single thread. This reduces the number of turns required to implant such a screw element (1). The thread core or thread valleys (53) is located between the thread turns. In the proximal area (30), an additional thread tooth (31, 32) is provided between each of the distal threads (51, 52). The proximal threads (31, 32) have the same pitch as the distal threads (51 and 52). Two cutting edges (41, 42) are formed in the transition area (40), whereby the second cutting edge (42) cannot be shown due to the view. It is the beginning (not visible here) for the second proximal thread (32). The cutting edges (41, 42) have the great clinical advantage that fractures during implantation can be prevented in the future with such screw elements (1). If, alternatively, a different thread is provided, the number of cutting edges is increased or reduced accordingly.

[0031] FIG. 1 also shows that the orientation (105) of the screw element (1) corresponds substantially to the direction of the central axis (103) and runs from proximal (101) to distal (102). The advantages have already been described at the beginning.

[0032] FIG. 2 shows a preferred embodiment of a screw element (1) in which the lateral fenestration openings (70) are formed as a polygon (700). The polygon (700) has at least one panel element (701, 702), which is mainly formed along the central axis (103). The distance between the panel elements (701 and 702) running parallel to the central axis (103) is smaller than the cannulation diameter D82 at the outlet (83). Furthermore, the polygon (700) has at least two panel elements (e.g. 703, 704, 705, 706) which, in a side view, are each oriented at an angle of from 25° to 65°, preferably from 35° to 55°, in particular from 40° to 50° with respect to the central axis (103). It is preferable if at least two of the panel elements (703, 704 or 705, 706) are oriented symmetrically with respect to the central axis (103). It is also possible for the panel elements (701-706) to merge into one another with the aid of curves (707).

[0033] FIG. 2 also shows that the lateral openings (70) are positioned in peripheral direction in ring-like formation (71 and/or 72) and, in the case of more than one peripheral direction ring-like formation (71 and 72), the openings (70) per formation have different opening cross-sectional areas (710, 720). Optimally, the opening cross-sectional area (710) of the distal formation (71) is larger than the opening cross-sectional area (720) of the proximal formation (72).

[0034] FIG. 3 shows a sectional view of the screw element (1). The interior of the head area (10) and the continuous cannulation (80) can be seen. The main feature of the head is that the head (10) has a larger outer diameter than the neck area (20). Preferably, the bone anchor has a tool attachment point (90) which is suitable for applying a torque. The torque for screwing in the bone anchor can thus be applied directly via the tool attachment point. This tool attachment point can have any profile (91, 92), such as a multi-tooth round, hexagon socket, cross recess, a simple slot or other toothing. According to the preferred embodiment, the tool attachment point (90) is positioned at the proximal end (101) and is bounded by a wall (93) in the distal direction (102). This wall (93) is formed as an inclination which extends radially inwards in increasing distal direction (102) and the cone angle formed by the wall is less than 120°. Optimally, the cone angle is substantially a right angle.

[0035] Furthermore, it can be seen that the tool attachment point (90) is open in proximal direction (101) and opens into a concentric cone-like recess (94) and has a substantially right-angled cone angle. The outer proximal ring functions as the support structure ring (95) described above.

[0036] FIG. 3 also shows the course of the cannulation opening (80). It is preferable if a section (81) with a slightly larger diameter is provided proximally, in which an application cannula can be inserted. Adjacent to this is the central section of the cannulation (82) with a diameter D82. The lateral openings (70) open into the cannulation (82) through corresponding outlets (83). It is advantageous if the cannulation diameter is reduced distally (102) in a distal cannulation section (84). The transitions (812, 834) between the different cannulation diameters ideally have a cone angle of less than 120°, preferably they are substantially right angled.

[0037] FIG. 4 shows two screw elements (1) according to the invention in combination with u-shaped fork heads (2) mounted with a connecting rod (4). The screw elements (1) have a proximal head area (10), which at least sectionally has a spherical segment, which is configured for providing a polyaxial pivotable connection with a fork head (2) that is u-shaped in a side view. After the connecting rod (4) has been inserted and the adjusting means (3) has been fixed, the screw elements (1) are connected to each other with angular stability. They form a rigid fixation, as used for example in spinal interventions.