Abstract
A surgical screw that is self-countersinking, self-tapping/fluted, self-drilling, and having a knurled shank designed for one step insertion. The screw has a stepped driving portion.
Claims
1. A screw comprising: a head having countersinking nibs; a shank that extends from the head and includes: a knurled portion; and a threaded portion; and cutting flutes opposite the head.
2. The screw of claim 1, wherein the head has a stepped driving portion.
3. The screw of claim 2, wherein the stepped driving portion comprises a Torx, square, double-square, triple-square, double hex, pentalobe, aster, clutch, pentagon, bristol, oval, and tri-lobe configuration.
4. The screw of claim 3, wherein the stepped driving portion are a same or different.
5. The screw of claim 1, wherein the screw is a one of a cannulated screw and a self tapping screw.
6. The screw of claim 1, further defining a thru hole that extends a length of the screw and configured for a K wire.
7. A kit comprising: a screw comprising: a head having countersinking nibs; a shank that extends from the head and includes: a knurled portion; and a threaded portion; and cutting flutes opposite the head, a measuring device; and a driver for the screw.
8. The kit of claim 7, further comprising a Kirschner guide wire.
9. The kit of claim 8, wherein the Kirschner guide wire is a 0.45 Kirschner guide wire.
10. The kit of claim 8, wherein the kit is a sterile pre-packaged instrument pack
11. The kit of claim 7, wherein the driver for the screw comprises a stepped driving portion configured to drive one or more of a Torx, square, double-square, triple-square, double hex, pentalobe, aster, clutch, pentagon, bristol, oval, and tri-lobe configuration.
12. The screw of claim 11, wherein the stepped driving portion are a same or different
Description
DESCRIPTION OF THE FIGURES
[0018] FIG. 1A is a prior art cortical screw;
[0019] FIG. 1B is a prior art cancellous screw;
[0020] FIG. 1C is a prior art cannulated screw;
[0021] FIG. 2 is a screw;
[0022] FIG. 3 is a top view of the screw of FIG. 2;
[0023] FIG. 4 is a cut-away view of a screw head;
[0024] FIG. 5 depicts placing a guide wire;
[0025] FIG. 6 depicts measuring for the screw;
[0026] FIG. 7 depicts placing the screw; and
[0027] FIG. 8 depicts the installed screw.
DETAILED DESCRIPTION
[0028] FIG. 2 is a side view of a screw 100. The screw 100 has a head 10. The head 10 is a self countersinking. The head 10 includes countersinking nibs 12. The self-countersinking head reduces risks of stress risers and over aggressive countersinking of cortical bone while limiting cortical stress. The shank 14 of the screw 100 includes a knurled portion 16. The knurled portion 16 allows for reduced friction and drag upon insertion of the screw 100.
[0029] Like all surgical screws, the screw 100 has a threaded portion 18. The threaded portion 18 is preferably a self tapping thread. The end of the screw 100 has sharp cutting flutes 20. The cutting flutes 20 allow for the self drilling and self tapping of the screw 100. Because the screw 100 is self drilling and self tapping, it has increased pull out strength so that it can provide greater overall compression than a screw that is inserted in a predrilled hole.
[0030] FIG. 3 is a top view the head 10 of the screw 100. As shown, the head 10 has two driving indentations 22, 24 for driving the screw 100. As shown in FIG. 4, the two driving indentations 22, 24 have different depths in the head 10. The two driving indentations 22, 24 provide additional driving torque compared to a single indent. The double drive also prevents stripping during insertion. While shown as hexagons, the driving indentations 22, 24 can be other shaped including star, marketed under the Torx name, square, double-square, triple-square, double hex, pentalobe, aster, clutch, pentagon, bristol, oval, tri-lobe, and the like. It should be noted that the two indents can be the same or different. A corresponding tool is used to drive the screw.
[0031] As seen in FIGS. 3 and 4, the screw is a cannulated screw. A thru hole 26 extends the length of the screw for use with a K wire. While shown as a cannulated screw, the in FIGS. 3 and 4, the self tapping and driving elements are applicable to any surgical screw.
[0032] Each section of the screw varies by application and overall length and diameter of the screw.
[0033] FIG. 5 depicts placing a guide wire. In use, a sterile pre-packaged instrument pack is opened. According to one aspect of the invention, the kit includes a 0.45 Kirschner guide wire, a measuring device, and driver. After identifying the optimum positioning of the screw, the supplied 0.45 Kirschner guide wire is inserted using a wire driver across the osteotomy or fracture site in the desired final position of the screw. The wire is advanced to the desired end length of the screw and is utilized to provisionally secure the capital fragment of bone. Correct guide wire placement can be confirmed utilizing intraoperative fluoroscopy.
[0034] FIG. 6 depicts measuring for the screw. Following insertion and positioning of the 0.45 guide wire, the provided measuring device is inserted over the 0.45 guide wire and the desired screw length is observed with the device flush against the near cortex of the bone. Bicortical purchase can be confirmed utilizing fluoroscopy.
[0035] FIG. 7 depicts placing the screw. Once the desired length is measured, the sterile pre-packaged screw of the corresponding length is opened and the screw is inserted over the previously placed guide wire. The screw is then advanced on the guide wire utilizing the provided driver until the near cortex is engaged by the threads of the screw. The screw is advanced by turning the driver in a clockwise motion. Prior to final tightening of the screw and achievement of compression, the self-countersinking heads will begin to engage the near cortex and will cut a recessed area of cortical bone so that the screw head sits flush with the near cortex. The screw should be advanced until the screw threads completely cross the osteotomy or fracture site and 1-2 screw threads cross the far cortex for increased pull-out strength. At this point the self-countersinking head will be securely seated in the near cortex of bone, and the osteotomy or fracture will be compressed. The process of under drilling, over drilling, tapping, and countersinking is performed in one step and the screw is inserted in one motion.
[0036] FIG. 8 depicts the installed screw, not to scale or fully seated. Prior to final tightening of the screw and achievement of compression, the self-countersinking heads will engage the near cortex and will cut a recessed area of cortical bone so that the screw head sits flush with the near cortex. The screw should be advanced until the screw threads completely cross the osteotomy or fracture site and 1-2 screw threads cross the far cortex for increased pull-out strength
[0037] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve substantially the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
