Easy starting of cannulated bone screws

Abstract

A surgical screw for fixation into bone or soft tissue is provided. The surgical screw includes a hollow body having a proximal end and a distal end. The distal end of the hollow body has a tapered tip, and a plurality of threads extend around the exterior of the hollow body. A guide extends distally from the tapered tip, and has a diameter (which can be variable or constant) that is less than the diameter of the tapered tip. The surgical screw is hollow such that a passageway extends through the body from the proximal end to (and sometimes through) the distal end.

Description

Easy-start hollow bone screw

[0001] This application is a divisional application of the application filed on September 28, 2018, with application number 201880065566.9 (international application number PCT / US2018 / 053412) and invention title "Easy-to-Start Hollow Bone Screw".

[0002] Cross-references to related applications

[0003] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 569,770 entitled “Easy Start Cannulated Bone Screw”, filed October 9, 2017, and U.S. Provisional Patent Application Serial No. 62 / 599,228 entitled “Easy Start Cannulated Bone Screw”, filed December 15, 2017. Technical Field

[0004] This disclosure relates generally to a surgical fixation device, and more specifically, to a hollow screw for fixation to bone or soft tissue. Background Technology

[0005] In orthopedic surgery, screws are commonly used to hold biological materials or other objects (such as implants) in desired positions relative to bone. For example, screws are used to attach bone blocks to existing bone or to fix soft tissue to bone or soft tissue. Initially screwing a screw into the bone or bone block can be difficult. Therefore, in some procedures, a pilot hole is required to help align the screw. As is well known in the surgical field, the pilot hole is smaller in depth and diameter than the screw to guide it, while still being narrow enough to allow sufficient thread penetration of the screw into the bony interference area. A bone hammer can also be used to hammer the screw into a depth sufficient to allow the thread to penetrate the bony interference area.

[0006] Drilling a guide hole requires additional surgical time and instruments. While hammering the screw into the bone with a bone hammer may take less time and require fewer instruments, it is less precise. Hammering the screw into the bone also carries a greater risk that the screw may not align with the desired fixation position. Therefore, a surgical screw is needed that does not require a guide hole or bone hammer while remaining firmly and reliably fixed within the bone. Summary of the Invention

[0007] This invention relates to a surgical screw. The surgical screw includes features for reducing the torque required to initiate the screw or to introduce the screw into an anatomical structure. According to one aspect, the surgical screw includes a hollow body having a proximal end and a distal end. The distal end of the hollow body may have a tapered tip and a plurality of threads extending from a position at the distal end, a position adjacent to the distal end, or a position proximal to the distal end around the exterior of the hollow body to a position at the proximal end, a position adjacent to the distal end, or a position distal to the proximal end. A guide extends distally from the tapered tip, and its diameter (which may be constant or variable) is smaller than the diameter of the tapered tip. The surgical screw is hollow, such that a channel extends from the proximal end through the body to the distal end.

[0008] According to another embodiment, the surgical screw includes a hollow body having a proximal end and a distal end, the hollow body having a tapered tip. Multiple threads (from the position described above) extend around the exterior of the hollow body. The multiple threads include a main thread and a secondary thread. The lead of the main thread is greater than the pitch of the multiple threads. A guide extends distally from the tapered tip. The surgical screw is hollow, such that a channel extends from the proximal end through the body to the distal end.

[0009] It should be understood that all combinations of the foregoing concepts and other concepts discussed in more detail below (provided that such concepts do not contradict each other) are considered part of the inventive subject matter disclosed herein. Specifically, all combinations of the claimed subject matter appearing at the end of this disclosure are considered part of the inventive subject matter disclosed herein. It should also be understood that terms expressly used herein that may also appear in any disclosure incorporated by reference shall be given the meaning most consistent with the specific concepts disclosed herein.

[0010] These and other aspects of the invention will become apparent and will be elucidated with reference to the embodiments described below. Attached Figure Description

[0011] One or more aspects of the invention are specifically pointed out and clearly claimed as examples in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings, wherein:

[0012] Figure 1 is a proximal fluoroscopic view of a surgical screw according to one embodiment;

[0013] Figure 2 is a distal perspective view of a surgical screw according to one embodiment;

[0014] Figure 3 is a side view of a surgical screw according to one embodiment;

[0015] Figure 4 is a perspective view of a surgical screw according to an alternative embodiment;

[0016] Figure 5 is a side view of a surgical screw according to an alternative embodiment;

[0017] Figure 6 is a distal perspective view of a surgical screw according to an alternative embodiment;

[0018] Figure 7 is a schematic diagram of the distal end of a surgical screw according to an alternative embodiment;

[0019] Figure 8 is a distal perspective view of a surgical screw according to one embodiment;

[0020] Figure 9 is a side view of a surgical screw according to an alternative embodiment; and

[0021] Figure 10 is a side view of a surgical screw according to another alternative embodiment;

[0022] Figure 11 is a side view of a surgical screw according to yet another alternative embodiment;

[0023] Figure 12 is a close-up schematic diagram of an exemplary embodiment of a surgical screw with a single head; and

[0024] Figure 13 is a close-up schematic diagram of an exemplary embodiment of a surgical screw with two heads. Detailed Implementation

[0025] The invention, along with certain features, advantages, and details thereof, is explained more fully below with reference to the non-limiting examples shown in the accompanying drawings. Descriptions of well-known structures have been omitted to avoid unnecessarily obscuring the invention in detail. However, it should be understood that the detailed descriptions and specific non-limiting examples, while indicating aspects of the invention, are given by way of illustration only and not by way of limitation. Various substitutions, modifications, additions, and / or arrangements within the spirit and / or scope of the basic concept of the invention will be apparent to those skilled in the art based on this disclosure.

[0026] Referring now to the accompanying drawings, wherein similar reference numerals refer to similar portions throughout, FIG1 shows a proximal perspective view of a surgical screw 100 according to one embodiment. The surgical screw 100 includes a body 102 extending between a proximal end 104 and a distal end 106. The surgical screw 100 may be made of any suitable biocompatible material such as titanium or magnesium and may be manufactured according to common manufacturing methods such as machining (as would be understood by one of ordinary skill in the art in conjunction with this disclosure). The surgical screw 100 may also be made of a biocomposite material and manufactured via injection molding (as would be understood by one of ordinary skill in the art in conjunction with this disclosure).

[0027] As shown in Figure 1, the body 102 includes a feature 108 at the proximal end 104 that allows the surgical screw 100 to be twisted. Specifically, the feature 108 is located on the outer surface 110 of the proximal end 104. For example, the feature 108 can be a feature of any conventional screw head, or it can be a feature of an unconventional geometry (e.g., a Tri-Lobe screwdriver geometry). In the depicted embodiment, the feature 108 has a hexagonal cross-section. As shown in Figure 1, the surgical screw 100 is hollow, such that a channel 112 extends from the feature 108 at the outer surface 110 of the proximal end 104 through the body 102 to the distal end 106.

[0028] Turning now to Figure 2, a distal perspective view of a surgical screw 100 according to one embodiment is shown. In the depicted embodiment, the body 102 of the surgical screw 100 includes a tip 114 at a distal end 106. In Figure 2, the tip 114 is a tapered region (at least partially tapered, tapering all the way to the distal end, and may include a constant, variable (increasing or decreasing) taper, or more than one taper with the same or different taper values ​​(separable from the non-tapered portion)) such that the body 102 tapers toward the distal end 106. As described above, the surgical screw 100 is hollow. Figure 2 shows a channel 112 extending through the body 102 of the surgical screw 100 to the tip 114 at the distal end 106. Specifically, the channel 112 extends from a feature 108 at the proximal end 104 to an opening 116 on the outer surface 118 of the tip 114.

[0029] Referring again to Figure 2, the surgical screw 100 includes a guide 120 at a tip 114. In the depicted embodiment, the guide 120 is an elongated extension extending from the tip 114. In the depicted embodiment, the guide 120 is a narrow cylinder extending from the tip 114 at a distal end 106. As shown, the guide 120 is also hollow, such that the guide 120 has an outer surface 118 and an opening 116 leading to a channel 112 extending through the body 102. The guide 120 allows for easier insertion of the surgical screw 100 because it can be used to align the surgical screw 100 at the desired bone hole location.

[0030] Referring now to Figure 3, a side view schematic diagram of a surgical screw 100 according to one embodiment is shown. As shown in Figure 3, the surgical screw 100 includes a plurality of threads 122 along the length of a body 102. As with all conventional screws, adjacent threads 122 have a pitch p and a root diameter d. However, in the depicted embodiment of the surgical screw 100, the pitch p and therefore the root diameter d can be variable / non-constant (or, the pitch can be variable and the root diameter can be constant, or vice versa, and the pitch and / or root diameter can be variable along one length of the body and constant along another). In other words, the threads 122 of the surgical screw 100 are not uniformly spaced. In one embodiment, the pitch p increases from the proximal end 104 to the distal end 106, while the root diameter d increases from the distal end 106 to the proximal end 104. For example, as shown in Figure 3, the pitch p1 at the distal end 106 is greater than the pitch p2 at the proximal end 104, and the bottom diameter at the distal end 106 is smaller than the bottom diameter at the proximal end 104.

[0031] Referring again to Figure 3, the thread 122 of the surgical screw 100 is a double-ended thread. A double-ended thread consists of two threads that are 180 degrees opposite each other. As shown in Figure 3, the surgical screw 100 includes staggered starting heads 124. In other words, the secondary thread 128 starts 180 degrees later than the primary thread 126. As shown in Figure 13, when the surgical screw 100 has double-ended or staggered starting heads 124, the primary thread 122A has a lead L that is greater than the pitch p of the threads 122 (122A, 122B). The surgical screw 100 may also have three or any additional multiple starts (not shown, as should be understood by one of ordinary skill in the art in conjunction with viewing this disclosure) or a single start (Figure 12), wherein the lead L and the pitch p are equal. In one embodiment, as shown in Figure 3, the primary thread 126 has a reduced surface area A. The reduced surface area A reduces resistance and torque during initial engagement with the bone.

[0032] Turning now to Figures 4 through 11, various schematic views of a surgical screw 100 according to an alternative embodiment are shown. First, in Figure 4, a perspective view of a surgical screw 100 according to an alternative embodiment is shown. Similar to the surgical screws 100 of Figures 1 through 3, the surgical screw 100 of Figure 4 includes a body 102 extending between a proximal end 104 and a distal end 106, the body having a feature 108 on an outer surface 110 at the proximal end 104 that allows the surgical screw 100 to be twisted. As shown in Figure 4, the surgical screw 100 is hollow, such that a channel 112 extends from the feature 108 at the outer surface 110 of the proximal end 104 through the body 102 to the distal end 106. Like the surgical screws 100 of Figures 1 through 3, the surgical screws 100 shown in Figures 4 through 11 can be made of any suitable biocompatible material such as titanium or magnesium or biocomposite materials, and can be manufactured according to common manufacturing methods such as machining or injection molding.

[0033] Figure 5 shows a side view of a surgical screw 100 according to an alternative embodiment. The surgical screw 100 shown in Figure 5 has a thread 122 extending along the body 102 of the screw 100. Adjacent threads 122 in the depicted embodiment have a constant (i.e., equal) pitch p. However, the surgical screw 100 may also have a thread 122 with variable pitches p1, p2, as shown in the embodiment in Figure 3. The embodiment of the surgical screw 100 in Figure 5 also has a thread 122 having a root diameter d that tapers from a proximal end 104 to a distal end 106. Specifically, the root diameter d decreases from the proximal end 104 to the distal end 106 (in some embodiments, its diameter may decrease constantly, and in other embodiments, its diameter may decrease non-constantly).

[0034] Referring again to Figure 5, embodiments of the surgical screw 100 also include a double-ended thread (i.e., an interleaved start head) 124. As described above, the double-ended thread 124 includes a primary thread 126 that is 180 degrees opposite to a secondary thread 128, such that the secondary thread 128 begins 180 degrees later than the primary thread 126 (i.e., around the outside of the body 102). However, in other embodiments, the secondary thread 128 may begin at least 5 degrees to at most 360 degrees later than the primary thread 126. The primary thread 126 and the secondary thread 128 have reduced surface areas A1, A2 to reduce resistance and torque during initial engagement with bone.

[0035] Turning now to Figures 6 and 7, a distal end and distal perspective view of a surgical screw 100 according to an alternative embodiment are shown. In the depicted embodiment of the surgical screw 100, the primary thread 126 and the secondary thread 128 are chamfered. The chamfer removes the leading edges of the primary and secondary threads, further reducing their surface areas A1, A2. As shown in Figure 6, the chamfer forms a first sharp edge 130 on the primary thread 126 and a second sharp edge 132 on the secondary thread 128. The sharp edges 130, 132 allow for better engagement between the surgical screw 100 and bone. In the depicted embodiment, the distal portion 134 of the primary thread 126 is configured such that the surface area A1 of the primary thread 126 is further reduced compared to the surface area A2 of the secondary thread 128. In another embodiment, when the surgical screw 100 is used to engage soft tissue relative to bone, a radius is used instead of a chamfer.

[0036] Referring now to FIG8, a distal perspective view of a surgical screw 100 according to one embodiment is shown. In the depicted embodiment, the surgical screw 100 includes a notch feature 136 at a distal end 106. In one embodiment, as shown in FIG8, the notch feature 136 extends from a guide 120 at the distal end 106 of the surgical screw 100. In the depicted embodiment, the notch feature 136 is a notch extending generally tangentially from the guide 120. When the bone is hard, the notch feature 136 can be hammered into the bone. For example, a surgeon aligns the guide 120 at the desired bone hole location and hammers the proximal end 104 of the surgical screw 100, causing the guide 120 and the notch feature 136 to engage with the bone. In another embodiment, as the surgical screw 100 rotates, the notch feature 136 is used to locate the gap between the main bone and the graft. When the notch feature 136 detects a gap, it guides the main thread 126 to the desired area, and the surgical screw 100 can be rotated and installed without hammering.

[0037] Turning now to Figures 9 and 10, a side view schematic diagram of a surgical screw 100 according to an alternative embodiment is shown. In the embodiment shown in Figures 9 and 10, the opening 116 leading to the channel 112 at the distal end 106 (guide 120) of the surgical screw 100 is solid or replaced by a solid feature 138. The solid feature 138 may be circular, as shown in Figure 9, or the solid feature 138 may have any other suitable geometry. For example, the solid feature 138 may be a drill tip 140, as shown in Figure 10. In the embodiment shown in Figures 9 and 10, the solid feature 138 is not hollow. However, in alternative embodiments, the hollow may also be completely removed (as shown in Figures 9 and 10) or only partially removed. In other words, the solid feature 138 may be completely solid or only partially solid.

[0038] Referring now to FIG11, a side view schematic diagram of a surgical screw 100 according to yet another embodiment is shown. In the depicted embodiment, the surgical screw 100 includes one or more external markings 142 along the body 102 between a proximal end 104 and a distal end 106. The external markings 142 of the surgical screw 100 in FIG11 are depth indicator markings 142. The depth indicator markings 142 are visible to the surgeon (or other user) during rotation and installation of the surgical screw 100. The depth indicator markings 142 allow the surgeon to determine the depth of the surgical screw 100 within bone or soft tissue. In the depicted embodiment, the depth indicator markings 142 are circumferential markings extending around the exterior of the surgical screw 100. However, the depth indicator markings 142 can be placed anywhere along the exterior of the surgical screw 100 such that they are visible to the surgeon (or other user). As shown in Figure 11, the depth indicator mark 142 may include multiple marks 142 spaced at equal intervals (e.g., 5 mm), a single depth mark, or multiple marks spaced at irregular intervals, and may be made of or coated with radiographic material.

[0039] All definitions defined and used herein should be understood to take precedence over dictionary definitions, definitions in referenced documents, and / or the general meaning of the defined terms.

[0040] Although various embodiments have been described and illustrated herein, those skilled in the art will readily conceive of various other means and / or structures for performing functions and / or obtaining results and / or one or more of the advantages described herein, and each of such variations and / or modifications is considered to be within the scope of the embodiments described herein. More generally, those skilled in the art will readily understand that all parameters, dimensions, materials, and configurations described herein are exemplary, and actual parameters, dimensions, materials, and / or configurations will depend on the specific application of the teachings of the invention for one or more specific applications therein. Those skilled in the art will recognize or be able to determine many equivalent forms of the specific embodiments described herein using only conventional experimentation. Therefore, it should be understood that the foregoing embodiments are given by way of example only, and that embodiments may be practiced in ways other than those specifically described and protected by the claims within the scope of the appended claims and their equivalents. Embodiments of this disclosure relate to each individual feature, system, article of manufacture, material, kit, and / or method described herein. Furthermore, any combination of two or more such features, systems, articles of manufacture, materials, kits, and / or methods is also included within the scope of this disclosure if these features, systems, articles of manufacture, materials, kits, and / or methods are not contradictory.

[0041] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well. It should also be understood that the terms “comprise” (and any form of “comprise” such as “comprises” and “comprising”), “have” (and any form of “have” such as “has” and “having”), “include” (and any form of “include” such as “includes” and “including”), and “contain” (and any form of “contain” such as “contains” and “containing”) are open-ended copulas. Thus, a method or apparatus that “comprises,” “have,” “includes,” or “contains” one or more steps or elements. Similarly, the elements of a method or apparatus that "comprises," "has," "includes," or "contains" one or more features have, but are not limited to, those features. Furthermore, an apparatus or structure constructed in a certain way is constructed at least in that manner, but may also be constructed in ways not listed.

[0042] All means or steps in the following claims, plus corresponding structures, materials, operations, and equivalents of the functional elements, are intended to include any structure, material, or operation for performing the function in combination with other claimed elements as specifically claimed. The invention has been described for purposes of illustration and description, but this description is not exhaustive or intended to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. The embodiments were chosen and described in order to best explain the principles and practical application of one or more aspects of the invention and to enable others skilled in the art to understand one or more aspects of the invention for various embodiments with various modifications suitable for the particular intended use.

Claims

1. A surgical screw comprising: A hollow body having a proximal end and a distal end, the distal end having a tapered tip; A multi-threaded thread, the thread being disposed around at least a portion of the exterior of the hollow body; a guide extending distally from the tapered tip; wherein the diameter of the guide is smaller than the diameter of the tapered tip; And a channel extending from the proximal end through the body to the distal end, wherein the multi-threaded structure includes a primary external thread and a secondary external thread, the secondary external thread starting 5 to 360 degrees later than the primary external thread, both the primary and secondary external threads being configured to at least surround the tapered tip region, wherein the primary external thread extends around the entire tapered tip region to the distal end of the tapered tip region, and wherein the primary external thread has a first edge having a first surface area at the tapered tip region, and the secondary external thread has a second edge having a second surface area at the tapered tip region, wherein the first surface area is smaller than the second surface area.

2. The surgical screw of claim 1, wherein the guide is a hollow cylinder such that the channel extends from the proximal end through the guide.

3. The surgical screw of claim 1, wherein the guide includes a solid feature portion.

4. The surgical screw according to claim 3, wherein the solid feature is a drill tip.

5. The surgical screw according to any one of the preceding claims further includes one or more external markings on the hollow body indicating depth.

6. A surgical screw, comprising: A hollow body having a proximal end and a distal end, the distal end having a tapered tip; A multi-threaded thread, the thread being disposed around at least a portion of the exterior of the hollow body; a guide extending distally from the tapered tip; wherein the diameter of the guide is smaller than the diameter of the tapered tip; The document also includes a channel extending from the proximal end through the body to the distal end, wherein the multi-threaded configuration comprises a primary external thread and a secondary external thread, the secondary external thread starting 5 to 360 degrees later than the primary external thread, both the primary and secondary external threads being configured to at least surround the tapered tip region, wherein at least the primary external thread extends around the entire tapered tip region to the distal end of the tapered tip region, and wherein the primary external thread has a first edge with a reduced surface area at its distal end, and wherein the primary external thread has a first edge with a first surface area at the tapered tip region, and the secondary external thread has a second edge with a second surface area at the tapered tip region, wherein the first surface area is smaller than the second surface area.

7. The surgical screw according to claim 6, wherein, The secondary external thread has a second edge with a reduced surface area at the tapered tip.

8. A surgical screw, comprising: A hollow body having a proximal end and a distal end, the distal end having a tapered tip; A multi-threaded thread, the thread being disposed around at least a portion of the exterior of the hollow body; a guide extending distally from the tapered tip; wherein the diameter of the guide is smaller than the diameter of the tapered tip; and a channel extending from the proximal end through the body to the distal end, wherein the multi-threaded configuration includes a primary external thread and a secondary external thread, wherein the secondary external thread begins 180 degrees later than the primary external thread, both the primary and secondary external threads are configured to at least surround the tapered tip, wherein the primary external thread extends around the entire tapered tip region to the distal end of the tapered tip region, and wherein the primary external thread has a first edge having a first surface area at the tapered tip, and the secondary external thread has a second edge having a second surface area at the tapered tip, wherein the first surface area is smaller than the second surface area.

9. The surgical screw of claim 8, wherein the first edge of the main external thread is chamfered.

10. The surgical screw of claim 9, wherein the second edge of the secondary external thread is chamfered.

11. The surgical screw according to claim 10, wherein, The first edge and the second edge intersect at the tip of the cone.

12. The surgical screw of claim 8, further comprising a notch feature extending from the guide.

13. The surgical screw according to claim 12, wherein, The notch feature is a notch that extends approximately tangentially from the guide.

14. The surgical screw according to claim 8, wherein, The hollow body is made of titanium.

15. The surgical screw according to claim 8, wherein, The lead of the main external thread is greater than the pitch of the multi-threaded thread.

16. The surgical screw of claim 8, wherein each pair of adjacent threads in the multi-threaded screw has a pitch and a root diameter, wherein each pitch is equal and each root diameter is equal.

17. The surgical screw of claim 8, wherein the multi-threaded screw comprises a first pair of adjacent threads and a second pair of adjacent threads, the first pair of adjacent threads having a first pitch and the second pair of adjacent threads having a second pitch, wherein the first pitch is greater than the second pitch.

18. The surgical screw according to claim 17, wherein, The first pair of adjacent threads has a first root diameter, and the second pair of adjacent threads has a second root diameter, wherein the first root diameter is larger than the second root diameter.

19. The surgical screw according to claim 8, wherein, The main external thread and the secondary external thread are at an angle relative to each other within the range of 5 degrees to 360 degrees.

20. The surgical screw of claim 19, wherein the primary external thread and the secondary external thread are approximately 180 degrees apart.

21. The surgical screw according to claim 8, wherein, The guide is a hollow cylinder.

22. A surgical screw, comprising: A hollow body having a proximal end and a distal end, the distal end having a tapered tip region; A multi-start thread, the thread being disposed around at least a portion of the exterior of the hollow body, and including a primary external thread and a secondary external thread; a guide, the guide extending distally from the tapered tip region; The diameter of the guide is smaller than the diameter of the tapered tip region; and a channel extends from the proximal end through the hollow body to the distal end, wherein the surgical screw includes an interlaced starting head at the tapered tip region, the secondary external thread starting 5 to 360 degrees later than the primary external thread, and wherein the primary external thread has a first edge having a first surface area at the tapered tip region, and the secondary external thread has a second edge having a second surface area at the tapered tip region, wherein the first surface area is smaller than the second surface area.

23. The surgical screw of claim 22, wherein the guide is a hollow cylinder such that the channel extends through the guide from the proximal end.

24. The surgical screw of claim 22, wherein the guide includes a solid feature portion.

25. The surgical screw of claim 24, wherein the solid feature is a drill tip.

26. The surgical screw of claim 22, further comprising one or more external markings on the hollow body indicating depth.

27. The surgical screw of claim 22, further comprising a protrusion extending from the guide.

28. The surgical screw of claim 27, wherein the protrusion is a notch extending substantially tangentially from the guide in the circumferential direction.

29. The surgical screw of claim 22, wherein the hollow body is made of titanium.

30. A surgical screw, comprising: A hollow body having a proximal end and a distal end, the distal end having a tapered tip region; A multi-start thread, wherein the thread is disposed around at least a portion of the exterior of the hollow body, and includes a main external thread and a secondary external thread; The lead of the main external thread is greater than the pitch of the multi-start thread; a guide extends distally from the tapered tip region; and a channel extending from the proximal end through the hollow body to the distal end, wherein the surgical screw includes an interlaced starting head at the tapered tip region, the secondary external thread starting 5 to 360 degrees later than the primary external thread, wherein the primary external thread has a first edge having a first surface area at the tapered tip region, and the secondary external thread has a second edge having a second surface area at the tapered tip region, wherein the first surface area is smaller than the second surface area.

31. The surgical screw of claim 30, wherein each pair of adjacent threads in the multi-threaded configuration has a pitch and a root diameter, wherein each pitch is equal and each root diameter is equal.

32. The surgical screw of claim 30, wherein the multi-threaded screw comprises a first pair of adjacent threads and a second pair of adjacent threads, the first pair of adjacent threads having a first pitch and the second pair of adjacent threads having a second pitch, wherein the first pitch is greater than the second pitch, the first pair of adjacent threads having a first root diameter and the second pair of adjacent threads having a second root diameter, wherein the first root diameter is greater than the second root diameter.

33. The surgical screw of claim 30, wherein the first edge and the second edge are chamfered.

34. The surgical screw of claim 30, wherein the first edge and the second edge are interlaced on the tapered tip.

35. The surgical screw of claim 30, wherein the primary external thread and the secondary external thread are 180 degrees apart.

36. The surgical screw according to any one of claims 30-35, wherein the guide is a hollow cylinder.

37. The surgical screw of any one of claims 30-35 further includes a notch extending generally tangentially from the guide.

Images