BONE SCREW

Abstract

The invention relates to a surgical instrument comprising a bone screw having a screw head, and a shaft for rotating the bone screw in a bone, the shaft and/or head forming a single element with the bone screw and having a predetermined breaking point. A driving element is inserted into the bone screw by the shaft, said driving element screwing the screw further in or out once the shaft has broken off from the screw.

Claims

1-15. (canceled)

16. A surgical instrument assembly comprising: a surgical instrument comprising: a bone screw with a screw head; and a shaft having a connector portion for screwing the bone screw into a bone; wherein the shaft with the bone screw is formed integrally and a predetermined breaking point is provided between the shaft and the screw head of the bone screw and the predetermined breaking point is configured break after reaching a specified torque relative the shaft to the screw head; and a knob or rod configured to removably connect to the connector portion of the shaft or the screw head of the bone screw.

17. The surgical instrument assembly of claim 16, comprising both a knob and a rod, wherein the knob is removably connected to the rod, and the rod is removably connected to the surgical instrument.

18. The surgical instrument assembly of claim 17, wherein the surgical instrument, the knob, and the rod have a plurality of connected channels configured for continuous cannulation of a substance or a filler material from an end of the knob to a tip of the surgical instrument.

19. The surgical instrument assembly of claim 16, wherein the knob or the rod has a spring loaded hook that removably connects to a groove located proximate the end of the shaft of the surgical instrument.

20. The surgical instrument assembly of claim 16, wherein the connector portion of the shaft has a projection with at least two notches that removably connect to at least two lugs located on the rod or knob.

21. The surgical instrument assembly of claim 16, wherein the knob or rod is reusable after attaching the bone screw into the bone via the removable connection between the knob and the shaft of the surgical instrument.

22. The surgical instrument assembly of claim 16, wherein the shaft of the surgical instrument has a bore aligned in a longitudinal direction configured to allow a portion of the knob or the shaft to pass through the bore of the shaft and engage an inner serration located on the screw head.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0035] Further advantages, features and details of the invention result from the following description of the embodiments as well as with the aid of the drawing; this shows in FIG. 1 a top view of a bone screw as per the invention;

[0036] FIG. 2 a section along a line II-II in FIG. 1;

[0037] FIG. 3 a perspective view of the invention-based bone screw as per FIG. 1;

[0038] FIG. 4 a lateral view of a screw driver as per the invention with the bone screw as per the invention;

[0039] FIG. 5 a top view of the invention-based screw driver as per FIG. 4 rotated around 90°;

[0040] FIG. 6 a perspective illustration of a position for a screw driver as per the invention;

[0041] FIG. 7 a perspective view of a screw driver as per the invention with positioning as per FIG. 6;

[0042] FIG. 8 an enlarged section from the screw driver as per FIG. 4 in the application field;

[0043] FIG. 9 a front view of a screw driver as per the invention with an invention-based bone screw and a magazine as per the invention.

[0044] FIG. 10 a cutaway lateral view of a surgical instrument as per the invention and a knob;

[0045] FIG. 11 an enlarged lateral view of a section from FIG. 10 from top view;

[0046] FIG. 12 a cut lateral view of another embodiment of a separate surgical instrument;

[0047] FIG. 13 an enlarged view inclined above a part of an assembled surgical instrument as per FIG. 12;

[0048] FIG. 14 a sectional lateral view of a surgical instrument as per FIG. 10 with set knob;

[0049] FIG. 15 an enlarged lateral view of a part of surgical instrument as per FIG. 14.

DETAILED DESCRIPTION

[0050] FIG. 1 shows a bone screw 1 as per the invention. This presents a shaft 2 as auxiliary material for positioning and a screw part 3. The screw part 3 comprises of a screw head 5 and a screw shaft 7. The screw shaft 7 of the screw part 3 is provided over the ca.⅔of its length with a self-cutting threading 6.

[0051] The shaft 2 is integrally connected over a predetermined breaking point 4 at the screw head 5 with the screw part 3. At the periphery of a sleeve section 30, the shaft 2 presents a surrounding groove 8 and a projection 9 shaped at the sleeve section 30. The projection 9 tapers at an end 28 at a diameter D, smaller than a diameter d of the shaft 2 and is connected with this tapered end 28 integrally with the screw part 3 and to the screw head 5. The tapered end 28 lies somewhat deep in a depression 29 in the screw head 5 and represents the predetermined breaking point 4.

[0052] As the section in FIG. 2 shows, the shaft 2 presents a central bore 10. This bore 10 goes through the shaft 2 so that a shearing area is annularly formed at the predetermined breaking point 4.

[0053] The screw head 5 presents a similar external contour like the section 9. In the screw head 5 and in the section 9 two square notches 11.1 and 11.3 as well as 11.2 and 11.4 are made with a breadth B. As shown in FIG. 3, the notches 11.1 and 11.2 align the opposite lying notches 11.3 and 11.4

[0054] Further FIG. 4 shows an invention-based screw driver 12 for implantation of an invention-based bone screw 1, for which separate claim is made. The screw driver 12 presents a tubular base part 13, a holder 14 and a shaft and screw slot 15.

[0055] In its front area the shaft and the screw slot 15, two axial, square-shaped sections 18.1 and 18.2 are created in such a way that between them a lug 19 is developed. Not shown here, two such opposite lying sections and a corresponding lug are arranged. In doing so the lug 19 is narrower than the width B of the notches 11.1 To 11.4, so that the lugs 19 can engage into the opposite lying notches 11.1 and 11.3 in the shaft 2 or the notches 11.2 and 11.4 in the screw head 5 respectively.

[0056] For the holder 14, a recess 16 is created in the tubular base part 13, which is designed as solid material and in to the screw recess 15, which is designed as hollow material. In the hollow material of the screw and shaft recess 15, an aperture 17 is provided. In the solid material of the base part 13, a clamping screw 20 is fitted with the aid of a bracket 21. The bracket 21 projects into the recess 16 and through the aperture 17 into an inner space of the shaft and screw recess 15. In doing so, the bracket 21 is bent in such a way that it can engage into the groove 8 in shaft 2 of the bone screw 1. Thus, the bone screw 1 is held in the screw driver 12.

[0057] FIG. 7 shows another, preferred embodiment as per the invention of a screw driver 12.1. The screw driver 12.1 conforms essentially to the invention-based screw driver 12, but distinguishes itself in the design of a holder 14.1.

[0058] The holder 14.1 is an integrally-formed part from a spring (see FIG. 6), formed and presents a shell-like base 23 with retaining plate 24.1 and 24.2. In the base parts 23, slit 27 is introduced in order to ensure a better grip, to increase flexibility and to save weight and material.

[0059] The base part 23 ends in a narrow web 25, which forms a kind of hook 26 at its tip. The holder 14.1 is placed with the shell-like base part 23 and the retaining plates 24.1 and 24.2 around a tubular base part 13.1 of the screw driver 12.1 In the process the hook 26 grips, as clearly evident from the section in FIG. 8, through an aperture 17.1 and into the groove 8 in the bone screw 1.

[0060] The functionality of the present invention is given below:

[0061] For implantation of the bone screw 1 as per the invention, this is set in an invention-based screw driver 12 or 12.1. In doing so, the lugs 18.1 and 18.2 engages in to the notches 11.1 and 11.3 in Section 9 of the shaft 2 of the bone screw 1.

[0062] In order to prevent the bone screw 1 from falling out of the screw driver 12 or 12.1, it is held through the holder 14 and 14.1 through intervention of the hook 26 in its groove 8. With screw driver 12.1 for accommodating the bone screw 1 the spring element is drawn back in the direction of arrow P, then the bone screw 1 can be used and the spring element is pushed against the direction of arrow P in such a way that the hook 26 engages in to the groove 8 and holds the bone screw 1.

[0063] Now, the bone screw 1 can be implanted and/or rotated or screwed-in in a bone and/or in an already cut hole. In the process the bone screw cuts off itself with its threading 6 a thread in the bone tissue.

[0064] With the exceedance of a defined torque, the shaft 2 shears at the predetermined breaking point 4 from the screw head 5 and the screw part 3. As a result, an annular shear area is formed, which is not shown here. As can be identifiable from FIG. 3, this lies slightly depressed in the screw head 5. The advantage is that the shear area which is formed mostly as rough area, cannot lead to irritation in the skin or in the flesh.

[0065] With the screw driver 12.1, it is especially advantageous that by pushing the holder 14.1 in the opposite direction of the arrow P, the sheared shaft 2 can be ejected by the hook 26 forwards from the screw driver 12.1 and its tubular base part 13.1.

[0066] After removing the shaft 2, the screw part 3 with the screw driver 12 or 12.1 is introduced into the pre-cut hole. For this purpose, the screw driver 12 and 12.1 with its lug 19 is introduced in to the notches 11.2 and 11.4 at the screw head 5. The screw part 3 can be removed by changing the direction of rotation out of the bone.

[0067] Advantageously, an assembly set as per the invention from the screw driver 12 and/or 12.1 and a bone screw 1 is supplemented through a magazine such as shown in FIG. 9. This magazine 31 serves the purpose, to accommodate the bone screw 1 free of rotation and to prepare for removal with the screw driver 12 and/or 12.1. In order to fulfill this task, it presents two holder plates 32.1 and 32.2. These arranged over each other in a space, which conforms to a height of the screw head 5 and the section 9, and present aligned openings 33 and 34. The opening 33 is created bigger than the largest diameter d.sub.1 of the bone screw 1. The bone screw can be guided through the hole. For this, the opening 34 is shaped in such a way that the bone screw 1 remains hanging with its screw head 5 at the lower holder plate 32.2. Preferably, such a magazine serves the purpose of accommodating many bone screws even in different lengths.

[0068] In FIG. 10, another embodiment of a surgical instrument R is shown. This comprises of shaft 2 and bone screw 1. At the bone screw 1, the screw head 5 is formed. Here, the advantage is that the transport and packaging costs can be saved, when the shaft 2 is downsized in shape, so that only the bone screw 1 is delivered with the shaft 2.

[0069] In this embodiment, the shaft 2 is introduced for centering in a recess 38 of the rod 37. Besides, the rod 37 possesses notches 43, which co-act with the corresponding engaging lugs 40, as they are recognized in FIG. 13, and bring about rotation of the bone screw 1 through shaft 2.

[0070] Besides, in FIG. 10 a knob 41 is shown. This knob 41 possesses a recess 42, which serves the purpose of accommodating the rod 37, especially the connector 43. Moreover, how a continuous cannulation is achieved through all the parts shown is recognized in FIG. 10. This continuous cannulation begins with channel 44 in the knob 41, continues in a channel 45 of the rod 37. In order that the cannulation can continue up to the bone screw 1, it is discerned in FIG. 12 well with the help of channel 46 in shaft 2 and a channel 47 in the bone screw.

[0071] FIG. 12 shows a bone screw 1, with which the bone screw head 5 is designed without a ridge. This has the advantage that the bone screw 1 can be completely sunk into a bone not shown here. Besides, how the bone screw 1 in FIG. 12 presents multiple grooving 48 is clearly identified.

[0072] FIG. 14 shows the surgical instrument R, which comprises shaft 2 and bone screw 1, which are connected with each other in the area of the screw head 5 as single part. The area F is again illustrated as enlarged in FIG. 15.

[0073] In FIG. 15, how the predetermined breaking point 4 is designed in the form of a depression in annular form is identified. Moreover, an inner serration 50 as well as a driver 49 is shown, which non-positively engage in to each other. In the process the driver is shaped as part of the bone screw 1 and the inner serration 50 as part of the shaft 2. Besides, a recess or additional counter-bore 48 is identified.