Abstract
A screw (1), in particular a bone screw, comprising a head (16), a shaft (2) and a point (15). The screw (1) has a recess (4) with a contour (5) on a head side (3), The screw (1) is provided with an insertion post (8) in the recess (4), which insertion post is connected to the screw (1) via a predetermined breaking point (7). After breaking the predetermined breaking point and separation of the insertion post (6) from the screw (12), a counter-contour (13) of a tool (12) can be brought into operative connection with the contour (5) of the recess (4). The predetermined breaking point (7) is arranged within the recess (4) such that, after removal of the insertion post (6), a transmission of torque is possible between the tool (12) and the screw (1) via the contour (5) and the counter-contour (13).
Claims
1-21. (canceled).
22. A screw, in particular bone screw, having a head, having a shank and having a tip, which screw, at a head side, has a recess with a contour, and wherein the screw is equipped, in the recess, with an insertion post which is connected to the screw by way of a predetermined breaking point, after breaking of the predetermined breaking point, a mating contour of a tool can be placed in operative connection with the contour of the recess, characterized in that the predetermined breaking point is arranged within the recess such that, after removal of the insertion post, a transmission of torque between the tool and the screw is possible by way of the contour and the mating contour.
23. The screw according to claim 22, wherein the predetermined breaking point is arranged so as to be set back relative to an end surface of the screw.
24. The screw according to claim 22, wherein the recess has an opening adjoining the contour.
25. The screw according to claim 22, wherein the screw and the insertion post have a cannulation.
28. The screw according to claim 22, wherein the predetermined breaking point is formed as a material weakening in a form of a constriction.
27. The screw according to claim 22, wherein the insertion post is equipped, integrally by way of the predetermined breaking point, with a post tip, and the post tip has a contour for transmission of torque via a mating contour in the recess of the screw.
28. The screw according to claim 22, wherein the insertion post is formed separately from the post tip and is connectable or connected to the post tip by way of the predetermined breaking point, and the post tip has a contour for a transmission of torque via a mating contour in the recess.
29. The screw according to claim 22, wherein the predetermined breaking point is designed so as to break in a presence of torque lower than the breakaway torque of the bone.
30. The screw according to claim 22, wherein the insertion post and the screw are of formed integrally with one another.
31. The screw according to claim 22, wherein the insertion post is screwed into a blind hole.
32. The screw according to claim 22, wherein the insertion post is pressed into a blind hole of the recess.
33. The screw according to claim 22, wherein the contour of the recess is in the form of one of a hexagon socket, a hexalobular socket, a square socket, or a Phillips socket.
34. The screw according to claim 22, wherein the screw and the insertion post comprise a biocompatible material from a list consisting of titanium, titanium alloys, steel, plastic, absorbable metal or absorbable plastic,
35. The screw according to claim 22, wherein the insertion post comprises a product-specific labelling which can be at least one of read off and preserved after breaking of the predetermined breaking point.
38. A set having at least one screw according to claim 22, and having a tool which has a mating contour, which is complementary to the contour of the recess of the screw.
37. A set having at least one tool having a mating contour with respect to the contour of the recess of the screw and having at least one screw according to claim 22.
38. The set according to claim 37, which additionally comprises a bone plate.
39. A method of producing a screw having an insertion post, the method comprising: providing a screw body which has a screw head, shank and screw tip, wherein the screw body has a recess with a contour for a tool, and providing an insertion post which is integrally connected to the screw and which is connected by way of a predetermined breaking point to a post tip, wherein the predetermined breaking point is arranged within the recess.
40. A method for producing a screw having an insertion post, the method comprising: providing a screw body having a head, a shank and a tip, wherein the screw body has a recess with a contour and an adjoining opening, providing a post which is connected byway of a predetermined breaking point to a post tip, and joining the post and the screw body together by way of the post tip and the opening.
41. The method according to claim 40, further comprising screwing the post into the screw body.
42. The method according to claim 40, further comprising pressing the post into the screw body.
Description
[0073] Further advantageous refinements of the invention will emerge from the following description of the exemplary embodiments in conjunction with the schematic figures. In the figures, in each case schematically:
[0074] FIGS. 1a/b: show a longitudinal section through a first embodiment of a screw according to the invention.
[0075] FIG. 2: shows a longitudinal section through an alternative embodiment of a screw according to the invention.
[0076] FIG. 3: shows a longitudinal section through a further embodiment of a screw according to the invention.
[0077] FIG. 4: shows a longitudinal section through a further embodiment of a screw according to the invention.
[0078] FIGS. 5a/b/c: show detail views of insertion posts according to the invention with different predetermined breaking points.
[0079] FIG. 6: shows a screw according to the invention after the twisting-off/breaking-off of the insertion post, with a tool.
[0080] FIG. 7: shows a longitudinal section through a first embodiment of a screw according to the invention after the twisting-off/breaking-off of the insertion post, with a tool.
[0081] FIG. 8: shows a longitudinal section through an alternative embodiment of a screw according to the invention after the twisting-off/breaking-off of the insertion post, with a tool.
[0082] FIG. 9: shows a cross section through a screw head of a screw according to the invention with insertion post.
[0083] FIGS. 1a and 1b show a longitudinal section through a first embodiment of a screw 1 according to the invention. The screw 1 has a shank 2 which is equipped with a thread 14. The screw 1 furthermore has a tip 15 and a screw head 16 situated opposite the tip 15. The screw head 16 has a head side 3. On the head side 3 there is formed a recess 4. An opening 8 for receiving a post tip 9 of an insertion post 6 is provided so as to adjoin the recess 4. The opening 8 for receiving the post tip 9 has an internal thread (not shown). The tip 9 has an external thread (not shown) which can be screwed into the internal thread of the opening 8.
[0084] In FIG. 1a, the post tip 9 is connected by way of a predetermined breaking point 7 to a post shank 20 of the insertion post 6. The post shank 20 is only partially illustrated in FIGS. 1a and 1b. The predetermined breaking point 7 is in this case in the form of a constriction between the tip 9 and the post shank 20. The insertion post 6 is thus connected indirectly to the screw 1 by way of the predetermined breaking point 7. The indirect connection of post tip and screw may be realized by way of a conical or cylindrical thread, by way of pressing, adhesive bonding, shrink-fitting, crimping or other connection methods, or by way of a combination of several of said connection methods. In the case of a connection that is realized for example only by way of pressing, adhesive bonding, shrink-fitting or crimping, the threads may also be omitted.
[0085] As the screw 1 is screwed in, the torque increases. The predetermined breaking point 7 is designed so as to break before the tightening torque is reached. In FIG. 1b, the post shank 20 of the insertion post 6 has broken off from the post tip 9 at the predetermined breaking point 7. The post tip 3 thus has a break point 18. The break point 18 is situated approximately at the level of the base surface 23 of the recess 4. In this way, the break point 18 does not come into contact with surrounding tissue, whereby irritation of said tissue is prevented.
[0086] The recess 4 has a contour 5. The contour is in the form of a hexalobular socket. After removal of the post shank 20 of the insertion post 6, the contour 5 is exposed. A tool 12 (see e.g. FIG. 6) with a matching mating contour 13 (see e.g. FIG. 6) can be placed in operative connection with the contour 5. By way of the tool 12, the screw 1 can be screwed into an end position. The screw 1 can also be unscrewed by way of the tool 12 when the screw 1 is no longer required.
[0087] FIG. 2 shows an alternative embodiment according to the invention of the screw 1. The insertion post 6 and the screw 1 are in this case of integral form. The two parts are manufactured from one piece of material. The predetermined breaking point 7 in this case directly forms the connecting point between the insertion post 6 and the screw 1. After a breaking-off of the insertion post 6 at the predetermined breaking point 7, a break point 8 will again be situated approximately at the level of the base surface 23 of the recess 4 (not shown). The recess again has a contour 5 by way of which the screw 1 can be screwed in further or unscrewed with the aid of the tool 12 (not shown) after the breaking-off of the predetermined breaking point 7.
[0088] FIG. 3 shows a farther embodiment of a screw 1 according to the invention. The screw 1 and the insertion post are, as in the embodiment of FIGS. 1a and 1b, connected indirectly by way of the predetermined breaking point 7. In this embodiment, the screw 1 is cannulated. The cannulation 19 extends in this case over the entire shank 2 of the screw 1. The insertion post also has a cannulation 21. The cannulations 19, 21 are fluidically connected when the insertion post 6 is in a screwed-in state. In this way, a continuous cannulation is realized.
[0089] Within the cannulations 19, 21 there is situated a wire 22, a so-called Kirschner wire or K-wire. Such wires 22 are used in various orthopedic and other operations. The wire 22 is inserted, into the bone. By way of the cannulation 19, 21, the screw 1 can be introduced over the wire 22 into the bone. Here, the wire 22 serves as a guide.
[0090] FIG. 4 shows a further embodiment of a screw 1 according to the invention. As in FIG. 3, a cannulation 19 is provided in the screw 1. The insertion post 6 and the screw 1 are, as in FIG. 2, of integral form. The cannulation 15 is formed all the way through the screw 1 and the insertion post 6. A wire 22 is again shown within the cannulation 19. The screw 1 has again been introduced by way of the cannulation 19 and the wire 22.
[0091] FIGS. 5a, b, c show detailed views of insertion posts 6. The insertion posts 6 nave post tips 9 and post shanks 20, which are connected to one another by way of predetermined breaking points 7.
[0092] In the embodiment shown in FIG. 5a, the predetermined breaking point 7 has been realized as a material variation. The predetermined breaking point 7 is thus formed with a material which is weaker in terms of failure than the post tip 9 and the post shank 20. The post tip 9 and the post shank 20 are for example manufactured from titanium, and the predetermined breaking point is manufactured for example from a biocompatible plastic which adhesively bonds the two parts. In this way, the predetermined breaking point 7 will fail at a certain torque.
[0093] In the embodiment shown in FIG. 5b, the predetermined breaking point 7 is in the form of a construction. The constriction has been formed by way of material removal at that location. The post tip 9 and the post shank 20 are of integral form.
[0094] In the embodiment shown in FIG. 5c, the predetermined breaking point has been formed by way of a connection with a reduced resistance to bending and torsion moments. Such connections may for example be welded connections. Alternative connections are pressed connections, shrink-fitted connections, crimped connections, adhesively bonded connections and other suitable connections, and also combinations of the connections.
[0095] FIG. 6 shows a screw 1 according to the invention after removal, of the post shank 20 of the insertion post 6 (not shown). A tool 12 has been inserted into the recess 4 (not visible in FIG. 6). Here, a mating contour 13 of the tool 12 is in operative connection with the contour 5 (not visible in FIG. 6) of the recess 4 (not visible in FIG. 6). The screw 1 can be screwed in yet further by way of the tool 12. When the screw is no longer required or must be explanted, the screw can be released by way of the tool 12.
[0096] The contour 5 (not visible) of the recess is for example in the form of a hexalobular socket. This common contour ensures that the screw 1 can be screwed in further and unscrewed by way of a standardized tool 12.
[0097] The tool 12 has, at an end situated opposite the mating contour 13, a connecting section 17, The connecting section 17 serves for the connection of the tool 12 to a screwing-in aid (not shown) such as for example a drilling machine or a screwdriver handle.
[0098] FIG. 7 shows a longitudinal section through the screw 1 of FIGS. 1a, b, after the post shank 20 of the insertion post 6 (not shown) has been removed and the tool 12 has been inserted, by way of the mating contour 13, into the recess 4.
[0099] FIG. 8 shows a longitudinal section through the screw 1 of FIG. 3, after the post shank 20 of the insertion post 6 (not shown) has been removed and the tool 12 has been inserted, by way of the mating contour 13, into the recess 4.
[0100] FIG. 9 shows a cross section through a screw head 16 at the level of the predetermined breaking point 7 of a screw 1 according to the invention with insertion post 6. The recess 1 of the screw head 16 has a contour 5 in the form of a hexalobular socket. After removal of the insertion post 6, the screw 1 can, by way of the contour 5, be screwed in yet further or unscrewed using the suitable tool 12 (not shown in FIG. 9).
