DE102014107495A1 - Bone screw system - Google Patents

Abstract

To a bone screw system comprising a bone screw with a longitudinal axis defining shaft and a K-wire, which shaft has a longitudinal channel parallel to the longitudinal axis, is provided with a Schaftaußengewinde and a distal, variable in its outer diameter shaft portion, wherein the K-wire corresponding or is formed substantially corresponding to the longitudinal channel, so to improve that a bone screw can be anchored stable in a bone, it is proposed that it comprises a cooperating with the distal shaft portion, arranged on the K-wire or formed spreading element for expanding the shaft portion.

Description

The present invention relates to a bone screw system comprising a bone screw with a shaft defining a longitudinal axis and a K-wire, which shaft has a longitudinal channel parallel to the longitudinal axis, is provided with a shank outer thread and has a distal, variable in its outer diameter shaft portion, wherein the K- Wire corresponding or substantially corresponding to the longitudinal channel is formed.

In spinal surgery, it is known, in particular for anchoring spinal stabilization systems, to use cannulated pedicle screws whose shaft has a longitudinal channel parallel to the longitudinal axis. In order to screw the bone screws in a defined way in a pedicle, K-wires are used, which are first driven as an insertion aid into the bone. Then the cannulated bone screw can be screwed over the K-wire to the bone and screwed into it. This allows good anchoring results to be achieved.

However, in special situations it is desirable to further improve the anchoring of the bone screw in the bone.

It is therefore an object to improve a bone screw system of the type described above so that a bone screw can be anchored more stable in a bone.

This object is achieved in a bone screw system of the type described above according to the invention in that it comprises a cooperating with the distal shaft portion, arranged or formed on the K-wire spreader for expanding the shaft portion.

The development proposed according to the invention makes it possible, in particular, to first drive the expansion element with the K-wire into a bone and then bring the bone screw over the K-wire to the bone. In this case, the expansion element cooperates with the distal, variable in its outer diameter shaft portion so that it is widened. In this way, therefore, an outer diameter of the distal shaft portion can be increased, by the interaction between the distal shaft portion and the expansion element. By widening the distal shaft portion, improved anchoring of the bone screw can be achieved. In particular, it is possible to use in the distal direction conically tapered and thus easily screwed into a bone bone screws, however, can be easily pulled out of a bone without the spreading of its distal end. With the improved bone screw system, bone screws with a distal, variable in its outer diameter shaft portion can be anchored easier and safer than previously known screws. In particular, the use of a K-wire for guiding and positioning the bone screw is also possible by arranging or forming the expansion element on the K-wire.

The bone screw is particularly easy to screw into a bone when the shaft tapers conically in the distal direction. In particular, the shaft can taper conically in the region of the distal shaft section.

Conveniently, the longitudinal channel is designed in the form of a longitudinal bore. This makes it possible to produce the longitudinal channel in a simple and reliable manner.

The bone screw can be anchored particularly securely in a bone when the external shaft thread is designed in the form of a bone thread. In particular, the shaft outer thread may be formed in the form of a self-tapping bone thread. Self-tapping bone threads allow the insertion of a bone screw, without the bone is massively displaced when inserting the bone screw. Rather, bone material is cut out of the bone.

In order to facilitate the introduction of the bone screw in the bone, it is advantageous if the shaft outer thread tapers in the distal direction. In particular, the shaft outer thread can taper in the region of the distal shaft section. Thus, for example, the bone screw with its distal shaft section can be introduced particularly easily into the bone and then widened in its outer diameter with the expansion element, in particular in this region, in order to improve anchoring of the bone screw in the bone.

The bone screw preferably has a shaft section inner thread formed on the shaft section. For example, in this way the expansion element, in particular if it has a corresponding external thread, can be screwed to the bone screw, in particular during expansion of the distal shaft section.

In a simple manner, the distal shaft portion can be made expandable if it is at least two separate, distally or substantially distally directed comprising spreading members. In particular, the spreading members may be formed flap-shaped or strip-shaped.

It is advantageous if the at least two spreading members are designed in the form of spreader vanes, which are separated from one another by slots extending in the proximal direction from the distal end of the shaft portion. In particular, it is thus possible for the spreader vanes to be able to move away from the longitudinal axis of the bone screw when expanding the distal shaft section starting from its distal end, that is, for example, they can be pivoted away from the longitudinal axis. The slots may extend over a portion of an overall length of the shaft of the bone screw, for example over a third or even about half of the total length.

It is favorable if the at least two spreading members comprise three, four, five or six spreading members. The more spreading members are provided, the narrower they are, so that they can be spread apart more easily.

According to a further preferred embodiment of the invention can be provided that the shaft portion is formed in the form of an elastic coil spring. For example, the coil spring may be formed in the form of the shaft outer thread, in which case the shank of the bone screw is completely removed in this region, in particular for the formation of the helical spring. In this case, the bone screw in the region of the distal shaft section merely consists of a shaft external thread in the form of a helical spring.

Particularly in the case of self-tapping shaft outer threads, it is favorable if the bone screw has at least one bone screw clamping groove which is arranged or formed in the region of the shaft outer thread. When screwing the bone screw into a bone then bone chips can be derived through the bone screw clamping in the proximal direction. As already described above, such a compression of the bone in which the bone screw is to be anchored, can be substantially avoided.

The interaction of the expansion element and the bone screw can be improved in a simple manner in particular by the fact that the expansion element comprises an expanding body which narrows in the proximal direction in diameter. Thus, an outer surface of the expansion element may in particular form a sliding surface for an inner surface of the distal shaft portion.

The introduction of the expansion element into the bone can be simplified in particular in that the expansion body carries or comprises an expansion body external thread. Thus, the spreader can be screwed into the bone. In particular, when the distal shaft portion includes a shaft portion internal thread, this may also interact with the Spreizkörperaußengewinde with appropriate design and thus allow a defined Aufspreizbewegung the distal shaft portion and optionally a coupling of the expansion element with the distal shaft portion.

It is favorable if the expansion element has at least one expansion element clamping groove which is arranged or formed in the region of the expansion body external thread. Thus, when inserting the expansion element into the bone with the Spreizkörperaußengewinde excised bone material can be removed in a simple and secure manner in the proximal direction.

The spreader element can be driven into the bone particularly easily when the spreader outer thread is designed in the form of a bone thread. In particular, the screwing of the expansion element into the bone can be further simplified if the spreader outer thread is designed in the form of a self-tapping bone thread.

Preferably, the Spreizkörperaußengewinde tapers in the proximal direction. Thus, as a whole, a spreading element can be formed with an outer contour that tapers in the proximal direction. The spreading of the distal shaft portion of the bone screw with the expansion element is thus made possible in a simple manner.

Further, it is advantageous if the Spreizkörperaußengewinde and the shaft outer thread are identical or substantially identical. In particular, thread pitches of the two threads can be identical. For example, the K-wire can be screwed into the bone with the expansion element. The bone screw introduced via the K-wire can then engage in the thread already cut by the expansion element in the bone, so that the bone is not merely displaced by radial spreading of the distal shaft section, but the implantation can take place without substantial compression of the bone. By avoiding the displacement of bone, it is also possible, in particular, to avoid so-called trabeculae being broken during the widening of the distal shaft section.

Preferably, the K-wire has a thickened distal end. Thus, he can form a stop for the expansion element in particular with its distal end to prevent slipping of the expansion element of the K-wire in the distal direction.

It is favorable if the spreading element is arranged or formed at a distal end or in the region of a distal end of the K-wire. In particular, a distal end of the K-wire can also define or form a distal end of the expansion element. Thus, the K-wire is introduced only as far as necessary in the bone.

In order to bring the expansion element in a defined manner in the bone, it is advantageous if the expansion element and the K-wire force, form and / or materially connected to each other. For example, the expansion element and the K-wire can be glued together. Thus, in particular, an axial and rotationally fixed connection between the expansion element and the K-wire can be formed.

Preferably, the bone screw system comprises a connecting device for non-positive and / or positive connection of the K-wire and the expansion element. Thus, for example, an axial and rotationally fixed connection can be formed without, but optionally also with, an adhesive.

In a simple way, the K-wire and the expansion element can be connected to one another when the connection device is designed in the form of a screw connection device.

The connecting device can be formed in a simple manner if it comprises first and second connecting elements which are arranged or formed on the spreader element on the one hand and on the K-wire on the other hand and engage with each other in a connecting position of the connecting device.

A secure connection between expansion element and bone screw can be achieved in particular by the fact that the first connecting element in the form of a connecting projection and that the second connecting element is designed in the form of a corresponding connection receiving. In particular, in the connecting position of the connecting projection engage positively or substantially positively in the connection receptacle.

In particular, it is advantageous if the first connecting element in the form of an externally threaded portion and when the second connecting element in the form of a corresponding internal thread portion are formed. For example, the spreader can be screwed onto the K-wire and connected to it.

According to a further preferred embodiment of the invention it can be provided that the bone screw system comprises a stop device for limiting a movement of the expansion element relative to the K-wire in the distal direction. In particular, the stop device can prevent the expansion element from being pushed or pushed down in the distal direction by the K-wire. For example, the stop means may comprise a thickened end of the K-wire.

It is advantageous if the stop device has a spreading element stop face pointing in a distal or essentially distally direction on the spreading element and / or a K wire stop face pointing in the proximal or substantially proximal direction. The expansion element abutment surfaces and K-wire abutment surfaces formed and aligned as described above make it possible to securely prevent the expansion element from distally sliding off the K-wire and becoming detached therefrom.

A simple and secure connection and / or slip-off protection can be formed, in particular, by the fact that the expansion element abutment surface and the K-wire abutment surface define mutually corresponding conical surfaces and / or are in the form of annular surfaces. For example, in the formation of conical surfaces, the expansion element can be coupled by a self-locking cone connection with the K-wire.

It is advantageous if the bone screw system comprises a coupling device for non-positive and / or positive coupling of the bone screw and the expansion element in a coupling position. The coupling device makes it possible, in particular, to connect spreaders and bone screws formed separately from one another temporarily or permanently. In this way, a particularly stable and permanent positioning of the bone screw in the bone can be achieved.

It is advantageous if the coupling device is designed in the form of a latching connection device. The latching connection device makes it possible, in particular, to bring the expansion element and the bone screw into engagement with one another, wherein the coupling position is automatically assumed by latching together interacting elements of the expansion element and the bone screw. In particular, the latching connection device may comprise a snap-on rib on the expansion element with which a corresponding projection on the bone screw can lock in the coupling position.

It is advantageous if the coupling device comprises first and second coupling elements, which are arranged or formed on the one hand on the bone screw and on the other hand on the expansion element and which engage with each other in the coupling position. This embodiment of the coupling device, a simple and secure coupling of the bone screw can be achieved with the expansion element in the coupling position.

The bone screw system can be formed in a particularly simple manner if the first coupling element is in the form of a coupling projection and if the second coupling element is in the form of a coupling recess. Preferably, the first and second coupling elements are oriented transversely to the longitudinal axis. This has the particular advantage that a disengagement of the first and second coupling elements is not possible only due to a movement of the expansion element and the bone screw parallel to their longitudinal axes. An unintentional release of the expansion element and the bone screw from each other is no longer readily possible.

According to a further preferred embodiment of the invention can be provided that the bone screw and the expansion element are integrally formed. The spreader and bone screw can be placed in a simple way in a train in a bone.

It is advantageous if the bone screw and the expansion element are connected to one another via at least one web. In particular, the web can be designed in the form of a predetermined breaking point. Furthermore, the bone screw, the at least one web and the expansion element may be integrally formed. The expansion element and the bone screw can be screwed together, for example, in the bone, in which case the predetermined breaking point is destroyed when a Einschraubmoments exceeded and then the bone screw and the spreader can be screwed independently into the bone. After severing the predetermined breaking point, in particular the bone screw and the expansion element can cooperate with one another in the manner described above for expanding the distal shaft section.

The handling of the bone screw system can be further simplified if the bone screw is formed at its proximal end in the form of a screw head or carries a screw head. This can in particular form a stop in order to limit the introduction into the bone. Furthermore, it is also possible to arrange or form on the screw head holding elements in one piece or in a separate construction, where, for example, connecting elements in the form of rods or plates can be set so as to position, for example, adjacent vertebrae in a defined manner relative to each other and hold.

It is advantageous if the screw head is spherical or substantially spherical. Thus, in particular a polyaxial screw can be formed with a mounted on the spherical screw head holding part which has a connecting element receiving for therein fixing a connecting element, for example in the form of a rod or a connecting plate with a rod-shaped connecting portion.

In order to be able to screw the bone screw into a bone in a simple manner, it is expedient for a tool element receptacle pointing in the proximal direction to be arranged or formed at a proximal end of the shaft.

The bone screw can be made particularly compact if the tool element receptacle is arranged or formed on the screw head. For example, with a cannulated Einschraubinstrument then the bone screw with the proximal direction of the screw head protruding and at least partially screwing through the Einschraubinstrument K-wire are screwed into a bone.

It is advantageous if the bone screw and / or the expansion element and / or the K-wire are made of at least one biocompatible metal and / or of at least one biocompatible plastic. Thus, the risk of rejection of the bone screw system by the body of the patient can be minimized.

Preferably, the at least one metal is titanium or a titanium alloy or a cobalt-chromium alloy or comprises the materials mentioned. This list is not exhaustive. In particular, all types of biocompatible metals are conceivable.

Conveniently, the at least one plastic is or comprises polyetheretherketone (PEEK). Alternatively, for example, polyethylene or polyarylsulfone or polyphenylsulfone (PSU, PPSU) can be used.

In order to improve the ingrowth and the stability of the connection between bone screw and bone, it is advantageous if the bone screw and / or the spreading element carry or have an osteointegrative coating. In particular, outer surfaces of the bone screw and / or the expansion element may be wholly or partially provided with such a coating.

It is advantageous if the coating is a osteointegrative Plasmapore ^® coating or titanium or calcium phosphide (Ca ₃ P ₂₎ is or contains. Such coatings optimize the ingrowth of the bone screw and / or the expansion element in the bone of a patient. This is particularly desirable if the bone screw is to be permanently anchored in a bone.

• 1. Knochenschraubensystem (10; 10a; 10b; 10c; 10d; 10e) umfassend eine Knochenschraube (12; 12a; 12e) mit einem eine Längsachse (18) definierenden Schaft (20) und einen K-Draht (14; 14c; 14d), welcher Schaft (20) einen Längskanal (34) parallel zur Längsachse (18) aufweist, mit einem Schaftaußengewinde (48) versehen ist und einen distalen, in seinem Außendurchmesser veränderbaren Schaftabschnitt (38; 38a; 38e) aufweist, wobei der K-Draht (14; 14c; 14d) korrespondierend oder im Wesentlichen korrespondierend zum Längskanal (34) ausgebildet ist, gekennzeichnet durch ein mit dem distalen Schaftabschnitt (38; 38a; 38e) zusammenwirkendes, am K-Draht (14; 14c; 14d) angeordnetes oder ausgebildetes Spreizelement (16; 16b; 16c; 16d) zum Aufweiten des Schaftabschnitts (38; 38a; 38e).
• 2. Knochenschraubensystem nach Satz 1, dadurch gekennzeichnet, dass sich der Schaft (20) in distaler Richtung konisch verjüngt, insbesondere im Bereich des distalen Schaftabschnitts (38; 38a; 38e).
• 3. Knochenschraubensystem nach Satz 1 oder 2, dadurch gekennzeichnet, dass der Längskanal (34) in Form einer Längsbohrung (36) ausgebildet ist.
• 4. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass das Schaftaußengewinde (48) in Form eines Knochengewindes (50) ausgebildet ist, insbesondere in Form eines selbstschneidenden Knochengewindes (50).
• 5. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass sich das Schaftaußengewinde (48) in distaler Richtung verjüngt, insbesondere im Bereich des distalen Schaftabschnitts (38; 38a; 38e).
• 6. Knochenschraubensystem nach einem der voranstehenden Sätze, gekennzeichnet durch ein am Schaftabschnitt (38) ausgebildetes Schaftabschnittinnengewinde (62).
• 7. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass der Schaftabschnitt (38) mindestens zwei voneinander getrennte, in distaler Richtung oder im Wesentlichen in distaler Richtung weisende Spreizglieder (44) umfasst.
• 8. Knochenschraubensystem nach Satz 7, dadurch gekennzeichnet, dass die mindestens zwei Spreizglieder (44) in Form von Spreizflügel (46) ausgebildet sind, welche durch sich vom distalen Ende des Schaftabschnitts (38) in proximaler Richtung erstreckende Schlitze (40) voneinander getrennt sind.
• 9. Knochenschraubensystem nach Satz 7 oder 8, dadurch gekennzeichnet, dass die mindestens zwei Spreizglieder (44) drei, vier, fünf oder sechs Spreizglieder (44) umfassen.
• 10. Knochenschraubensystem nach einem der Sätze 1 bis 5, dadurch gekennzeichnet, dass der Schaftabschnitt (38e) in Form einer elastischen Schraubenfeder (130e) ausgebildet ist.
• 11. Knochenschraubensystem nach einem der Sätze 1 bis 9, dadurch gekennzeichnet, dass die Knochenschraube (12) mindestens eine Knochenschraubenspannut (58) aufweist, die im Bereich des Schaftaußengewindes (48) angeordnet oder ausgebildet ist.
• 12. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass das Spreizelement (16; 16b; 16c; 16d) einen sich in proximaler Richtung im Durchmesser verjüngenden Spreizkörper (74; 74b) umfasst.
• 13. Knochenschraubensystem nach Satz 12, dadurch gekennzeichnet, dass der Spreizkörper (74) ein Spreizkörperaußengewinde (76) trägt oder umfasst.
• 14. Knochenschraubensystem nach Satz 13, dadurch gekennzeichnet, dass das Spreizelement (16; 16b; 16c; 16d) mindestens eine Spreizelementspannut (118) aufweist, die im Bereich des Spreizkörperaußengewindes (76) angeordnet oder ausgebildet ist.
• 15. Knochenschraubensystem nach Satz 13 oder 14, dadurch gekennzeichnet, dass das Spreizkörperaußengewinde (76) in Form eines Knochengewindes (77) ausgebildet ist, insbesondere in Form eines selbstschneidenden Knochengewindes (77).
• 16. Knochenschraubensystem nach einem der Sätze 13 bis 15, dadurch gekennzeichnet, dass sich das Spreizkörperaußengewinde (76) in proximaler Richtung verjüngt.
• 17. Knochenschraubensystem nach einem der Sätze 13 bis 16, dadurch gekennzeichnet, dass das Spreizkörperaußengewinde (76) und das Schaftaußengewinde (48) identisch oder im Wesentlichen identisch ausgebildet sind.
• 18. Knochenschraubensystem nach einem der Sätze 13 bis 17, dadurch gekennzeichnet, dass das Schaftabschnittinnengewinde (62) korrespondierend zum Spreizkörperaußengewinde (76) ausgebildet ist.
• 19. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass der K-Draht (14; 14c; 14d) ein verdicktes distales Ende (64; 64c; 64d) aufweist.
• 20. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass das Spreizelement (16; 16b; 16c; 16d) an einem distalen Ende (64; 64c; 64d) oder im Bereich eines distalen Endes (64; 64c; 64d) des K-Drahts (14; 14c; 14d) angeordnet oder ausgebildet ist.
• 21. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass das Spreizelement (16; 16b; 16c; 16d) und der K-Draht (14; 14c; 14d) kraft-, form- und/oder stoffschlüssig miteinander verbunden sind.
• 22. Knochenschraubensystem nach einem der voranstehenden Sätze, gekennzeichnet durch eine Verbindungseinrichtung (94; 94c; 94d) zum kraft- und/oder formschlüssigen Verbinden des K-Drahts (14; 14c; 14d) und des Spreizelements (16; 16b; 16c; 16d) in einer Verbindungsstellung.
• 23. Knochenschraubensystem nach Satz 22, dadurch gekennzeichnet, dass die Verbindungseinrichtung (94c) in Form einer Schraubverbindungseinrichtung (124c) ausgebildet ist.
• 24. Knochenschraubensystem nach Satz 22 oder 23, dadurch gekennzeichnet, dass die Verbindungseinrichtung (94; 94c; 94d) erste und zweite Verbindungselemente (96, 100; 96c, 100c; 96d, 100d) umfasst, die einerseits am Spreizelement (16; 16b; 16c; 16d) und andererseits am K-Draht (14; 14c; 14d) angeordnet oder ausgebildet sind und in der Verbindungsstellung miteinander in Eingriff stehen.
• 25. Knochenschraubensystem nach Satz 24, dadurch gekennzeichnet, dass das erste Verbindungselement (96; 96d) in Form eines Verbindungsvorsprungs (98; 98d) und dass das zweite Verbindungselement (100; 100d) in Form einer korrespondierenden Verbindungsaufnahme (102; 102d) ausgebildet ist.
• 26. Knochenschraubensystem nach Satz 24 oder 25, dadurch gekennzeichnet, dass das erste Verbindungselement (96c) in Form eines Außengewindeabschnitts (126c) und dass das zweite Verbindungselement (100c) in Form eines korrespondierenden Innengewindeabschnitts (128c) ausgebildet sind.
• 27. Knochenschraubensystem nach einem der voranstehenden Sätze, gekennzeichnet durch eine Anschlageinrichtung (92; 92d) zum Begrenzen einer Bewegung des Spreizelements (16; 16d) relativ zum K-Draht (14; 14d) in distaler Richtung.
• 28. Knochenschraubensystem nach Satz 27, dadurch gekennzeichnet, dass die Anschlageinrichtung (92; 92d) eine in distaler oder im Wesentlichen in distaler Richtung weisende Spreizelementanschlagfläche (88; 88d) am Spreizelement (16; 16d) und/oder eine in proximaler oder im Wesentlichen in proximaler Richtung weisende K-Draht-Anschlagfläche (90; 90d) am K-Draht (14; 14d) aufweist.
• 29. Knochenschraubensystem nach Satz 28, dadurch gekennzeichnet, dass die Spreizelementanschlagfläche (88) und die K-Draht-Anschlagfläche (90) zueinander korrespondierende konische Flächen definieren und/oder in Form von Ringflächen ausgebildet sind.
• 30. Knochenschraubensystem nach einem der voranstehenden Sätze, gekennzeichnet durch eine Kopplungseinrichtung (104) zum kraft- und/oder formschlüssigen Koppeln der Knochenschraube (12) und des Spreizelements (16) in einer Koppelstellung.
• 31. Knochenschraubensystem nach Satz 30, dadurch gekennzeichnet, dass die Kopplungseinrichtung (104) in Form einer Rastverbindungseinrichtung ausgebildet ist.
• 32. Knochenschraubensystem nach Satz 30 oder 31, dadurch gekennzeichnet, dass die Kopplungseinrichtung (104) erste und zweite Kopplungselemente (106, 108) umfasst, welche einerseits an der Knochenschraube (12) und andererseits am Spreizelement (16) angeordnet oder ausgebildet sind und welche in der Koppelstellung miteinander in Eingriff stehen.
• 33. Knochenschraubensystem nach Satz 32, dadurch gekennzeichnet, dass das erste Kopplungselement (106) in Form eines Kopplungsvorsprungs und dass das zweite Kopplungselement (108) in Form einer Kopplungsausnehmung ausgebildet sind, die insbesondere quer zur Längsachse orientiert sind.
• 34. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass die Knochenschraube (12) und das Spreizelement (16) einstückig ausgebildet sind.
• 35. Knochenschraubensystem nach Satz 34, dadurch gekennzeichnet, dass die Knochenschraube (12) und das Spreizelement (16) über mindestens einen Steg miteinander verbunden sind, welcher in Form einer Sollbruchstelle ausgebildet ist.
• 36. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass die Knochenschraube (12; 12a; 12e) an ihrem proximalen Ende in Form eines Schraubenkopfes (24; 24a) ausgebildet ist oder einen Schraubenkopf (24; 24a) trägt.
• 37. Knochenschraubensystem nach Satz 36, dadurch gekennzeichnet, dass der Schraubenkopf (24; 24a) kugelig oder im Wesentlichen kugelig ausgebildet ist.
• 38. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass an einem proximalen Ende des Schafts (20) eine in proximaler Richtung weisende Werkzeugelementaufnahme (30) angeordnet oder ausgebildet ist.
• 39. Knochenschraubensystem nach Satz 38, dadurch gekennzeichnet, dass die Werkzeugelementaufnahme (30) am Schraubenkopf (24; 24a) angeordnet oder ausgebildet ist.
• 40. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass die Knochenschraube (12; 12a; 12e) und/oder das Spreizelement (16; 16b; 16c; 16d) und/oder der K-Draht (14; 14c; 14d) aus mindestens einem körperverträglichen Metall und/oder aus mindestens einem körperverträglichen Kunststoff hergestellt sind.
• 41. Knochenschraubensystem nach Satz 40, dadurch gekennzeichnet, dass das mindestens eine Metall Titan, eine Titanlegierung oder eine Kobalt-Chrom-Legierung ist oder umfasst.
• 42. Knochenschraubensystem nach Satz 40 oder 41, dadurch gekennzeichnet, dass der mindestens eine Kunststoff Polyetheretherketon ist oder umfasst.
• 43. Knochenschraubensystem nach einem der voranstehenden Sätze, dadurch gekennzeichnet, dass die Knochenschraube (12; 12a; 12e) und/oder das Spreizelement (16; 16b; 16c; 16d) und/oder der K-Draht (14; 14c; 14d) eine osteointegrative Beschichtung tragen oder aufweisen.
• 44. Knochenschraubensystem nach Satz 43, dadurch gekennzeichnet, dass die osteointegrative Beschichtung eine Plasmapore^®-Beschichtung ist oder Titan oder Kalziumphosphid (Ca₃P₂) ist oder enthält.

The above description thus includes in particular the embodiments of bone screw systems defined below in the form of numbered sets:

• 1. bone screw system ( 10 ; 10a ; 10b ; 10c ; 10d ; 10e ) comprising a bone screw ( 12 ; 12a ; 12e ) with a longitudinal axis ( 18 ) defining shaft ( 20 ) and a K-wire ( 14 ; 14c ; 14d ), which shaft ( 20 ) a longitudinal channel ( 34 ) parallel to the longitudinal axis ( 18 ), with a shaft outer thread ( 48 ) and a distal, in its outer diameter variable shaft portion ( 38 ; 38a ; 38e ), wherein the K-wire ( 14 ; 14c ; 14d ) corresponding or substantially corresponding to the longitudinal channel ( 34 ) is formed, characterized by a with the distal shaft portion ( 38 ; 38a ; 38e ) cooperating, on the K-wire ( 14 ; 14c ; 14d ) arranged or formed spreading element ( 16 ; 16b ; 16c ; 16d ) for expanding the shaft portion ( 38 ; 38a ; 38e ).
• 2. Bone screw system according to sentence 1, characterized in that the shaft ( 20 ) tapers conically in the distal direction, in particular in the region of the distal shaft section (FIG. 38 ; 38a ; 38e ).
• 3. Bone screw system according to sentence 1 or 2, characterized in that the longitudinal channel ( 34 ) in the form of a longitudinal bore ( 36 ) is trained.
• 4. Bone screw system according to one of the preceding sentences, characterized in that the shaft outer thread ( 48 ) in the form of a bone thread ( 50 ) is formed, in particular in the form of a self-tapping bone thread ( 50 ).
• 5. Bone screw system according to one of the preceding sentences, characterized in that the shaft outer thread ( 48 ) in the distal direction, in particular in the region of the distal shaft portion (FIG. 38 ; 38a ; 38e ).
• 6. Bone screw system according to one of the preceding sentences, characterized by a shaft portion ( 38 ) formed shank portion internal thread ( 62 ).
• 7. Bone screw system according to one of the preceding sentences, characterized in that the shaft portion ( 38 ) at least two separate, in the distal direction or substantially in the distal direction facing spreading members ( 44 ).
• 8. Bone screw system according to sentence 7, characterized in that the at least two spreading members ( 44 ) in the form of spreader wings ( 46 formed by the distal end of the shank portion (FIG. 38 ) extending in the proximal direction slots ( 40 ) are separated from each other.
• 9. bone screw system according to sentence 7 or 8, characterized in that the at least two spreading members ( 44 ) three, four, five or six expansion elements ( 44 ).
• 10. Bone screw system according to one of the sentences 1 to 5, characterized in that the shaft portion ( 38e ) in the form of an elastic coil spring ( 130e ) is trained.
• 11. Bone screw system according to one of the sentences 1 to 9, characterized in that the bone screw ( 12 ) at least one bone screw clamping ( 58 ), which in the region of the shaft outer thread ( 48 ) is arranged or formed.
• 12. Bone screw system according to one of the preceding sentences, characterized in that the expansion element ( 16 ; 16b ; 16c ; 16d ) an expanding in the proximal direction in diameter spreader ( 74 ; 74b ).
• 13. Bone screw system according to sentence 12, characterized in that the expansion body ( 74 ) an expander outer thread ( 76 ) bears or comprises.
• 14. Bone screw system according to sentence 13, characterized in that the expansion element ( 16 ; 16b ; 16c ; 16d ) at least one Spreizelementspannut ( 118 ), which in the region of the Spreizkörperaußengewindes ( 76 ) is arranged or formed.
• 15. Bone screw system according to sentence 13 or 14, characterized in that the Spreizkörperaußeninde ( 76 ) in the form of a bone thread ( 77 ) is formed, in particular in the form of a self-tapping bone thread ( 77 ).
• 16. Bone screw system according to one of the sentences 13 to 15, characterized in that the Spreizkörperaußeninde ( 76 ) tapers in the proximal direction.
• 17. Bone screw system according to one of the sentences 13 to 16, characterized in that the spreader outer thread ( 76 ) and the shaft outer thread ( 48 ) are identical or substantially identical.
• 18. Bone screw system according to one of the sentences 13 to 17, characterized in that the shaft section internal thread ( 62 ) corresponding to the Spreizkörperaußeninde ( 76 ) is trained.
• 19. Bone screw system according to one of the preceding sentences, characterized in that the K-wire ( 14 ; 14c ; 14d ) a thickened distal end ( 64 ; 64c ; 64d ) having.
• 20. Bone screw system according to one of the preceding sentences, characterized in that the expansion element ( 16 ; 16b ; 16c ; 16d ) at a distal end ( 64 ; 64c ; 64d ) or in the area of a distal end ( 64 ; 64c ; 64d ) of the K-wire ( 14 ; 14c ; 14d ) is arranged or formed.
• 21. Bone screw system according to one of the preceding sentences, characterized in that the expansion element ( 16 ; 16b ; 16c ; 16d ) and the K-wire ( 14 ; 14c ; 14d ) are positively, positively and / or cohesively connected to each other.
• 22. Bone screw system according to one of the preceding sentences, characterized by a connecting device ( 94 ; 94c ; 94d ) for positive and / or positive connection of the K-wire ( 14 ; 14c ; 14d ) and the expansion element ( 16 ; 16b ; 16c ; 16d ) in a connection position.
• 23. Bone screw system according to sentence 22, characterized in that the connecting device ( 94c ) in the form of a screw connection device ( 124c ) is trained.
• 24. Bone screw system according to sentence 22 or 23, characterized in that the connecting device ( 94 ; 94c ; 94d ) first and second connecting elements ( 96 . 100 ; 96c . 100c ; 96d . 100d ), on the one hand on the expansion element ( 16 ; 16b ; 16c ; 16d ) and on the other hand on the K-wire ( 14 ; 14c ; 14d ) are arranged or formed and in the connecting position engage with each other.
• 25. Bone screw system according to sentence 24, characterized in that the first connecting element ( 96 ; 96d ) in the form of a connection projection ( 98 ; 98d ) and that the second connecting element ( 100 ; 100d ) in the form of a corresponding connection recording ( 102 ; 102d ) is trained.
• 26. Bone screw system according to sentence 24 or 25, characterized in that the first connecting element ( 96c ) in the form of an externally threaded portion ( 126c ) and that the second connecting element ( 100c ) in the form of a corresponding internal thread section ( 128c ) are formed.
• 27. Bone screw system according to one of the preceding sentences, characterized by a stop device ( 92 ; 92d ) for limiting a movement of the expansion element ( 16 ; 16d ) relative to the K-wire ( 14 ; 14d ) in the distal direction.
• 28. Bone screw system according to sentence 27, characterized in that the stop device ( 92 ; 92d ) a spreading element stop surface (13) pointing in a distal or substantially distal direction (FIG. 88 ; 88d ) on the expansion element ( 16 ; 16d ) and / or in a proximal or substantially proximal direction K-wire-abutment surface ( 90 ; 90d ) on the K-wire ( 14 ; 14d ) having.
• 29. Bone screw system according to sentence 28, characterized in that the Spreizelementanschlagfläche ( 88 ) and the K-wire stop surface ( 90 ) define mutually corresponding conical surfaces and / or are formed in the form of annular surfaces.
• 30. Bone screw system according to one of the preceding sentences, characterized by a coupling device ( 104 ) for non-positive and / or positive coupling of the bone screw ( 12 ) and the expansion element ( 16 ) in a coupling position.
• 31. Bone screw system according to sentence 30, characterized in that the coupling device ( 104 ) is designed in the form of a latching connection device.
• 32. Bone screw system according to sentence 30 or 31, characterized in that the coupling device ( 104 ) first and second coupling elements ( 106 . 108 ), which on the one hand on the bone screw ( 12 ) and on the other hand on the expansion element ( 16 ) are arranged or formed and which are engaged with each other in the coupling position.
• 33. Bone screw system according to sentence 32, characterized in that the first coupling element ( 106 ) in the form of a coupling projection and that the second coupling element ( 108 ) are formed in the form of a coupling recess, which are oriented in particular transversely to the longitudinal axis.
• 34. Bone screw system according to one of the preceding sentences, characterized in that the bone screw ( 12 ) and the spreading element ( 16 ) are integrally formed.
• 35. Bone screw system according to sentence 34, characterized in that the bone screw ( 12 ) and the spreading element ( 16 ) are connected to each other via at least one web, which is designed in the form of a predetermined breaking point.
• 36. Bone screw system according to one of the preceding sentences, characterized in that the bone screw ( 12 ; 12a ; 12e ) at its proximal end in the form of a screw head ( 24 ; 24a ) is formed or a screw head ( 24 ; 24a ) wearing.
• 37. Bone screw system according to sentence 36, characterized in that the screw head ( 24 ; 24a ) is spherical or substantially spherical.
• 38. Bone screw system according to one of the preceding sentences, characterized in that at a proximal end of the shaft ( 20 ) a pointing in the proximal direction tool element receptacle ( 30 ) is arranged or formed.
• 39. Bone screw system according to sentence 38, characterized in that the tool element receptacle ( 30 ) on the screw head ( 24 ; 24a ) is arranged or formed.
• 40. Bone screw system according to one of the preceding sentences, characterized in that the bone screw ( 12 ; 12a ; 12e ) and / or the expansion element ( 16 ; 16b ; 16c ; 16d ) and / or the K-wire ( 14 ; 14c ; 14d ) are made of at least one biocompatible metal and / or at least one biocompatible plastic.
• 41. Bone screw system according to sentence 40, characterized in that the at least one metal is or comprises titanium, a titanium alloy or a cobalt-chromium alloy.
• 42. Bone screw system according to sentence 40 or 41, characterized in that the at least one plastic is or comprises polyetheretherketone.
• 43. Bone screw system according to one of the preceding sentences, characterized in that the bone screw ( 12 ; 12a ; 12e ) and / or the expansion element ( 16 ; 16b ; 16c ; 16d ) and / or the K-wire ( 14 ; 14c ; 14d ) carry or have an osteointegrative coating.
• 44. bone screw system according to sentence 43, characterized in that the coating is a osteointegrative Plasmapore ^® coating or titanium or calcium phosphide (Ca ₃ P ₂₎ is or contains.

The following description of preferred embodiments of the invention is used in conjunction with the drawings for further explanation. Show it:

1 a schematic side view of a first embodiment of a bone screw system with a bone screw, a K-wire and a spreading element;

2 : a perspective view of the bone screw system 1 from distal;

3 : a longitudinal sectional view of the bone screw system 1 in an expanded position during the interaction of the expansion element and the bone screw;

4 : a longitudinal sectional view analog 3 a second embodiment of a bone screw system;

5 : a longitudinal sectional view analog 3 a third embodiment of a bone screw system;

6 : a longitudinal sectional view analog 3 a fourth embodiment of a bone screw system;

7 : a longitudinal sectional view analog 3 a fifth embodiment of a bone screw system;

8th : a sectional view along line 8-8 in 7 ;

9 : a view similar 2 of the bone screw system 7 ;

10 a perspective view of a portion of a sixth embodiment of a bone screw system;

11 : a partial side view of the bone screw system 10 ; and

12 : a schematic representation of the bone screw system 1 when introduced into a pedicle of a vertebra.

In the 1 to 3 is a total with the reference numeral 10 designated bone screw system exemplified. It includes a bone screw 12 , a K-wire 14 and a spreading element 16 ,

The bone screw 12 includes an elongated, a longitudinal axis 18 defining shaft 20 , at its proximal end 22 a spherical screw head 24 is arranged. He is through an annular constriction 26 separated from the shaft.

At the screw head 24 is a flat, extending transversely to the longitudinal axis end surface 28 educated. A tool element holder 30 at the screw head 24 is open in the proximal direction and coaxial with the longitudinal axis 18 educated. It is in the form of a polygonal or Innenvielrund 32 educated.

Through the shaft 20 through a longitudinal channel extends 34 in the form of a coaxial to the longitudinal axis 18 extending longitudinal bore 36 ,

The bone screw 12 further includes a variable in its outer diameter distal shaft portion 38 on.

Four circumferentially offset by 90 ° to each other slots 40 extending from a distal end 42 the bone screw 12 in the proximal direction about half the length of the shaft 20 parallel to the longitudinal axis 18 extend, separate four expansion members 44 from each other, in the form of itself parallel to the longitudinal axis 18 extending Spreizflügeln 46 are formed.

The shaft 20 tapers from its proximal end 22 distally to its end 42 conical.

On the shaft 20 is also a shank external thread 48 formed, in the form of a self-tapping bone thread 50 , A slope of the bone thread 50 is constant. The height 52 of the bone thread 50 related to a thread root 54 increases in the distal direction. Overall, an outer contour 56 the bone screw 12 in the area of the shaft outer thread 48 provided shaft 20 defined, which is conical in the distal direction to the end 42 rejuvenated.

Further, on the bone screw 12 in the region of the external shaft thread 48 , starting from the end 42 , a bone screw tensioning 58 designed for removing bone chips. The bone screw tensioning groove 58 defines a longitudinal axis 60 facing the longitudinal axis 18 is inclined and skewed to this runs. The bone screw tensioning groove 58 extends to slightly less than half of a length of the distal shaft portion 38 ,

Starting from the end 42 is in the region of the distal shaft section 38 a shank portion internal thread 62 educated.

The K-wire 14 has a thickened distal end 64 on.

An inner diameter 70 of the longitudinal channel 34 extends in a single stage distally in the area of proximal ends 66 the slots 40 ,

An outer diameter 68 of the K-wire 14 is at an inner diameter 70 of the longitudinal channel 34 between the constriction 26 and the ends 66 customized. An inner diameter 72 of the longitudinal channel 34 in the region of the shaft section 36 is almost twice the size of the inside diameter 70 ,

The spreading element 16 comprises an expanding body which narrows in diameter in the proximal direction 74 , This carries a Spreizkörperaußeninde 76 which is a height 78 related to a thread root 80 which decreases in the proximal direction. The spreader outer thread 76 defines a tapering in the proximal direction outer contour 82 ,

The spreader outer thread 76 corresponds to the shaft outer thread 48 that is, it has the same slope. Furthermore, the Spreizkörperaußengewinde corresponds 76 to the shank portion internal thread 62 and can be engaged with this.

The spreading element 16 has a coaxial with the longitudinal axis 18 extending bore 84 on, located in the area of a distal end 86 slightly conically widened. In this way, a partially distally facing conical Spreizelementanschlagfläche 88 defined at a corresponding K-wire stop surface 90 of the thickened end 64 is applied.

The Spreizelementanschlagfläche 88 and the K-wire abutment surface 90 thus form mutually corresponding surfaces of a stop device 92 for limiting a movement of the expansion element 16 relative to the K-wire 14 in the distal direction.

Preferably, the conical, abutting surfaces of the stopper 92 such with respect to the longitudinal axis 18 inclined that a self-locking clamping connection between the spreader 16 and the thickened end 64 of the K-wire 14 will be produced.

Optionally, the spreader 16 with the K-wire 14 additionally also connected with an adhesive and / or welded or soldered thereto. Preferably, the spreading element 16 both parallel to the longitudinal axis 18 as well as in the circumferential direction relative to the longitudinal axis 18 firmly with the K-wire 14 connected.

As described thus is for connecting the spreader 16 with the K-wire 14 a connection device 94 provided, which is a first connecting element 96 in the form of a connection projection 98 on the K wire 14 and a second connecting element 100 in the form of a connection projection 98 corresponding connection reception on the expansion element 16 includes.

The bone screw system 10 further comprises a coupling device 104 for non-positive and / or positive coupling of the bone screw 12 and the spreading element 16 in a coupling position, as for example in 3 is shown schematically.

The coupling device 104 includes first and second coupling elements 106 and 108 on the one hand on the bone screw 12 and on the other hand on the expansion element 16 are arranged or formed and are engaged with each other in the coupling position. In the in the 1 to 3 illustrated embodiment of the bone screw system 10 forms the shaft portion internal thread 62 the first coupling element 106 , the spreader outer thread 76 the second coupling element 108 ,

The implantation technique for inserting the bone screw system 10 into a pedicle 110 a vortex 112 a spine 114 a patient is schematic in 12 and is briefly explained below.

In a first step, as a spreading screw 116 trained spreading element 16 that with the K-wire 14 axially and rotationally firmly connected, in the pedicle 110 brought in. The self-tapping spreader outer thread 76 allows it, the spreader 16 directly at the desired location and with the optimal orientation in the pedicle 110 screwed. This is facilitated in particular by the fact that the expansion body 74 a spreader outer thread 76 partially interrupting expansion element clamping 118 having slightly inclined with respect to the longitudinal axis 18 runs and is skewed to this oriented.

Is the expanding body 74 in the pedicle 110 placed, can come from proximal bone screw 12 with her end 42 progressing over a proximal end 120 of the K-wire 14 pushed and to the spreader 16 be introduced.

By the corresponding design of the shaft portion internal thread 62 and the Spreizköperaußengewindes 76 can the bone screw 12 on the spreader 16 be screwed on. It is particularly advantageous if a maximum outer diameter of the shaft outer thread 48 in the area of the end 42 is not greater than a maximum outer diameter of the Spreizköperaußengewindes 76 , This facilitates the screwing of the bone screw 12 on the expansion screw 116 ,

Because the shaft outer thread 48 and the spreader outer thread 76 have the same thread pitch, the shaft outer thread 48 directly into the pedicle 110 through the expansion screw 116 precut female threads are screwed.

The further the bone screw 12 in the distal direction on the spreader 16 is screwed on, however, the more the spreading elements spread apart 44 on and widen the distal shaft section 38 on. It is not only bone displaced, whereby bone trabeculae could be broken, but the self-tapping bone thread 50 cuts further into the pedicle 110 with cut-out bone material passing through the bone screw grooves 58 is derived in the proximal direction.

The screwing in of the expansion element 16 with the K-wire 14 done with an appropriate tool, which is the K-wire 14 in the area of his end 120 can hold against rotation.

Screwing in the bone screw 12 is performed with a cannulated instrument, not shown in the figures, which has a distal end of the tool, which corresponds to the tool element receiving 30 is trained. A longitudinal channel of the instrument is at the outer diameter 68 of the K-wire 14 customized.

Is the bone screw system 10 placed in the desired manner becomes the K-wire 14 in the area of the screw head 24 , preferably in the tool element holder 30 , separated, so that it no longer proximally over the screw head 24 protrudes.

Alternatively, it is also possible to use the K-wire 14 in the area of the screw head 24 to jam.

In case of a required revision or removal of the bone screw system 10 First, the bone screw 12 turned back and removed.

Subsequently, the expansion screw 116 together with the K-wire 14 unscrewed. The K-wire 14 can be clamped for example with an instrument with jaw chuck.

A second embodiment of a total with the reference numeral 10a designated bone screw system is schematically in 4 shown. It only differs in the structure of the bone screw 12a from the bone screw system 10 ,

The bone screw 12a is almost identical to the bone screw 12 educated. It only differs from the bone screw 12 in that it has no shaft section internal thread. This is not a positive coupling between the spreader 16 and the bone screw 12a possible, but only a frictional coupling by clamping when sliding the distal shaft portion 38a with the sash wings 46a on the Spreizköperaußengewinde 76 ,

In 5 is a total with the reference numeral 10b designated third embodiment of a bone screw system schematically shown. It differs from the bone screw system 10a in that the spreading element 16b has no Spreizköperaußengewinde. In other words, the expansion element 16b through the expanding body 74b formed without Spreizköperaußengewinde.

When implanting the bone screw system 10b becomes the expansion element 16b in the absence of Spreizköperaußengewindes not screwed, but in the pedicle 110 taken. A coupling between the distal shaft portion 38a and the spreader 16b is purely frictional by clamping.

In 6 is schematically a fourth and in total by the reference numeral 10c designated embodiment of a bone screw system shown. It differs from the bone screw system 10 only by the formation of the connecting device 94c , So it includes the bone screw 12 , the K-wire 14c and the spreader 16c ,

The connection device 14c is in the form of a screw connection device 124c formed and includes a first connecting element 96c forming external thread 126c in the area of the end 64c of the K-wire 14c and one to the external thread 126c corresponding internal thread 128c which is a second connecting element 100c forms.

By the described embodiment, the K-wire 14c with the expansion element 16c be screwed. To the connection of the K-wire 14 and the spreader 16c to secure against unintentional loosening, in addition to the connecting device 94c a cohesive connection can be provided, for example by gluing, soldering or welding.

In the 7 to 9 is a fifth embodiment of a total reference numeral 10d designated bone screw system shown schematically. It differs from the bone screw system 10 again in the embodiment of the connecting device 94d as well as the anchor device 92d ,

The end 64d of the K-wire 14d is thickened and has a square cross-section. Overall, such a substantially parallelepiped connection projection 98d formed, which is a first connecting element 96d Are defined. The corresponding second connecting element 100d is formed by a connection recording 102d on the expansion element 16d , which is open in the distal direction.

The connection projection 98 and the connection recording 102 are formed corresponding to each other, so that the connecting projection 98d positively in the connection recording 102d can dip until one in the transition area of the hole 84d to connect 102d trained Spreizelementanschlagfläche 88d on a K-wire abutment surface pointing in the proximal direction 90d the connection projection 98d strikes.

Due to the non-circular shape of the connecting projection 98 is a rotationally fixed connection between the spreader 16d and the K-wire 14d ensured. An axial securing can additionally be realized cohesively, for example by gluing, soldering or welding.

A sixth embodiment of the in the 10 and 11 schematically shown bone screw system 10 is in total by the reference numeral 10e designated. It differs in its construction from the bone screw system 10 through the design of the bone screw 12e , essentially by the design of the distal shaft portion 38e , This one is at the bone screw 12e by a coil spring 130e educated.

So there are no spreading members 44 like the bone screw 12 provided, but only a section starting from the end 42e in the proximal direction, acting as a helical spring 130 is designed.

The coil spring 130 also sets the shaft outer thread 48 Therefore, it can also be in the pedicle 110 or cut another bone.

For example, for the preparation of the bone screw 12e be assumed by a screw body, as well as for the preparation of the bone screw 12 serves. But instead of the slots 40 and the bone screw chuck 58 to be provided, starting from the end 42e the shaft 20 completely removed, so that practically only the shaft outer thread 48 remains, which then the coil spring 130 forms.

Not shown in the figures is another embodiment of a bone screw system. In this, the distal end of the bone screw can be connected to a proximal end of the expansion element via one or more webs, which are designed as predetermined breaking points. If a screw-in torque is exceeded when screwing in the bone screw system, which is formed as a whole, the bridge breaks or breaks and a multi-part bone screw system remains, as described above in the various embodiments.

The implantation of bone screw systems 10a . 10b . 10c . 10d and 10e takes place substantially in accordance with the above in connection with the implantation of the bone screw system 10 described procedure.

As materials for the bone screw systems described, titanium, titanium alloys, cobalt-chromium alloys, nitinol or the like are preferably used. Alternatively, the bone screws and the spreading elements, optionally also the K-wires, may be made of a plastic, for example PEEK or PPSU or PE.

Optionally, all elements of the bone screw systems individually, partially or entirely provided with an osteointegrative coating, for example with a Plasmapore ^® or a CaP coating.

Also advantageous are material combinations of PEEK and titanium. For example, the spreading elements 16 made of PEEK, the bone screws 12 however, from a metal. In particular, a friction between the spreading elements 16 and the bone screws 12 optimized and the screwing be facilitated.

LIST OF REFERENCE NUMBERS

10, 10a, 10b, 10c, 10d, 10e

Bone screw system

12, 12a, 12e

bone screw

14, 14c, 14d

K-wire

16, 16b, 16c, 16d

spreader

18

longitudinal axis

20

shaft

22

The End

24, 24a

screw head

26

constriction

28

end face

30

Tool element receiver

32

Internal polygon

34

longitudinal channel

36

longitudinal bore

38, 38a, 38e

shank portion

40

slot

42, 42e

The End

44

spreading member

46

Spreizflügel

48

Shank external thread

50

Bone thread

52

height

54

thread base

56

outer contour

58

Knochenschraubenspannut

60

longitudinal axis

62

Shank portion female thread

64, 64c, 64d

The End

66

The End

68

outer diameter

70

Inner diameter

72

Inner diameter

74, 74b

spreader

76

Spreizköperaußengewinde

77

Bone thread

78

height

80

thread base

82

outer contour

84

drilling

86

The End

88, 88d

Spreizelementanschlagfläche

90

K-wire stop surface

92, 92d

stop device

94, 94c, 94d

connecting device

96, 96c, 96d

first connecting element

98, 98d

connecting projection

100, 100c, 100d

second connecting element

102, 102d

connection Low

104

coupling device

106

first coupling element

108

second coupling element

110

pedicle

112

whirl

114

spinal column

116

expander

118

Spreizelementspannut

120

The End

122

outer surface

124c

Schraubverbindungseinrichtung

126c

external thread

128c

inner thread

130e

coil spring

Claims (25)

Bone screw system ( 10 ; 10a ; 10b ; 10c ; 10d ; 10e ) comprising a bone screw ( 12 ; 12a ; 12e ) with a longitudinal axis ( 18 ) defining shaft ( 20 ) and a K-wire ( 14 ; 14c ; 14d ), which shaft ( 20 ) a longitudinal channel ( 34 ) parallel to the longitudinal axis ( 18 ), with a shaft outer thread ( 48 ) is provided and a distal, variable in its outer diameter Shaft section ( 38 ; 38a ; 38e ), wherein the K-wire ( 14 ; 14c ; 14d ) corresponding or substantially corresponding to the longitudinal channel ( 34 ) is formed, characterized by a with the distal shaft portion ( 38 ; 38a ; 38e ) cooperating, on the K-wire ( 14 ; 14c ; 14d ) arranged or formed spreading element ( 16 ; 16b ; 16c ; 16d ) for expanding the shaft portion ( 38 ; 38a ; 38e ). Bone screw system according to claim 1, characterized in that the shaft ( 20 ) tapers conically in the distal direction, in particular in the region of the distal shaft section (FIG. 38 ; 38a ; 38e ). Bone screw system according to claim 1 or 2, characterized in that the longitudinal channel ( 34 ) in the form of a longitudinal bore ( 36 ) is trained. Bone screw system according to one of the preceding claims, characterized by a shaft portion ( 38 ) formed shank portion internal thread ( 62 ). Bone screw system according to one of the preceding claims, characterized in that the shaft portion ( 38 ) at least two separate, in the distal direction or substantially in the distal direction facing spreading members ( 44 ). Bone screw system according to one of the preceding claims, characterized in that the expansion element ( 16 ; 16b ; 16c ; 16d ) an expanding in the proximal direction in diameter spreader ( 74 ; 74b ). Bone screw system according to claim 6, characterized in that the expansion body ( 74 ) an expander outer thread ( 76 ) bears or comprises. Bone screw system according to claim 7, characterized in that the Spreizkörperaußeninde ( 76 ) in the form of a bone thread ( 77 ) is formed, in particular in the form of a self-tapping bone thread ( 77 ). Bone screw system according to claim 7 or 8, characterized in that the Spreizkörperaußeninde ( 76 ) tapers in the proximal direction. Bone screw system according to one of claims 7 to 9, characterized in that the Spreizkörperaußeninde ( 76 ) and the shaft outer thread ( 48 ) are identical or substantially identical. Bone screw system according to one of the preceding claims, characterized in that the K-wire ( 14 ; 14c ; 14d ) a thickened distal end ( 64 ; 64c ; 64d ) having. Bone screw system according to one of the preceding claims, characterized in that the expansion element ( 16 ; 16b ; 16c ; 16d ) at a distal end ( 64 ; 64c ; 64d ) or in the area of a distal end ( 64 ; 64c ; 64d ) of the K-wire ( 14 ; 14c ; 14d ) is arranged or formed. Bone screw system according to one of the preceding claims, characterized in that the expansion element ( 16 ; 16b ; 16c ; 16d ) and the K-wire ( 14 ; 14c ; 14d ) are positively, positively and / or cohesively connected to each other. Bone screw system according to one of the preceding claims, characterized by a connecting device ( 94 ; 94c ; 94d ) for positive and / or positive connection of the K-wire ( 14 ; 14c ; 14d ) and the expansion element ( 16 ; 16b ; 16c ; 16d ) in a connection position. Bone screw system according to claim 14, characterized in that the connecting device ( 94c ) in the form of a screw connection device ( 124c ) is trained. Bone screw system according to claim 14 or 15, characterized in that the connecting device ( 94 ; 94c ; 94d ) first and second connecting elements ( 96 . 100 ; 96c . 100c ; 96d . 100d ), on the one hand on the expansion element ( 16 ; 16b ; 16c ; 16d ) and on the other hand on the K-wire ( 14 ; 14c ; 14d ) are arranged or formed and in the connecting position engage with each other. Bone screw system according to one of the preceding claims, characterized by a stop device ( 92 ; 92d ) for limiting a movement of the expansion element ( 16 ; 16d ) relative to the K-wire ( 14 ; 14d ) in the distal direction. Bone screw system according to claim 17, characterized in that the stop device ( 92 ; 92d ) a spreading element stop surface (13) pointing in a distal or substantially distal direction (FIG. 88 ; 88d ) on the expansion element ( 16 ; 16d ) and / or in a proximal or substantially proximal direction K-wire-abutment surface ( 90 ; 90d ) on the K-wire ( 14 ; 14d ) having. Bone screw system according to one of the preceding claims, characterized by a coupling device ( 104 ) for non-positive and / or positive coupling of the bone screw ( 12 ) and the expansion element ( 16 ) in a coupling position. Bone screw system according to claim 19, characterized in that the coupling device ( 104 ) is designed in the form of a latching connection device. Bone screw system according to claim 19 or 20, characterized in that the coupling device ( 104 ) first and second coupling elements ( 106 . 108 ), which on the one hand on the bone screw ( 12 ) and on the other hand on the expansion element ( 16 ) are arranged or formed and which are engaged with each other in the coupling position. Bone screw system according to claim 21, characterized in that the first coupling element ( 106 ) in the form of a coupling projection and that the second coupling element ( 108 ) are formed in the form of a coupling recess, which are oriented in particular transversely to the longitudinal axis. Bone screw system according to one of the preceding claims, characterized in that the bone screw ( 12 ) and the spreading element ( 16 ) are integrally formed. Bone screw system according to claim 23, characterized in that the bone screw ( 12 ) and the spreading element ( 16 ) are connected to each other via at least one web, which is designed in the form of a predetermined breaking point. Bone screw system according to one of the preceding claims, characterized in that the bone screw ( 12 ; 12a ; 12e ) and / or the expansion element ( 16 ; 16b ; 16c ; 16d ) and / or the K-wire ( 14 ; 14c ; 14d ) carry or have an osteointegrative coating.

Images