초록 ▼

A bone screw is provided for securing a medical device to bone. The bone screw can engage with a bone screw hole in a medical device, such as an anterior cervical plate or sternal closure plate. Embodiments of the bone screw can include a screw head, a smooth cylindrical shaft region, a first and a

A bone screw is provided for securing a medical device to bone. The bone screw can engage with a bone screw hole in a medical device, such as an anterior cervical plate or sternal closure plate. Embodiments of the bone screw can include a screw head, a smooth cylindrical shaft region, a first and a second cylindrical shaft region with external threading, a tapered shaft region with external threading and one or more recessed flutes, and a sharp tip without threading or fluting. The external threading in the first and the second cylindrical shaft regions can have different pitches and crests. The external threading on the tapered shaft region can be tapered.

대표청구항 ▼

1. A bone screw, comprising: a) a screw head;b) a smooth cylindrical shaft region, wherein said smooth cylindrical shaft region is adjacent to said screw head and is unthreaded to disengage from a bone screw hole upon full insertion;c) a first cylindrical shaft region comprising external threading,

1. A bone screw, comprising: a) a screw head;b) a smooth cylindrical shaft region, wherein said smooth cylindrical shaft region is adjacent to said screw head and is unthreaded to disengage from a bone screw hole upon full insertion;c) a first cylindrical shaft region comprising external threading, said threading of said first cylindrical shaft region having a first pitch, a first crest width, and a first thread diameter larger than a diameter of said bone screw hole to engage with said bone screw hole, wherein said first crest width is adapted to resist shearing when engaging with said bone screw hole;d) a second cylindrical shaft region comprising external threading, said threading of said second cylindrical shaft region having a pitch that transitions over one to three revolutions from said first pitch to a second smaller pitch, having a crest width that transitions over said one to three revolutions from said first crest width to a second smaller crest width, and having a thread diameter substantially equal to said first thread diameter;e) a tapered shaft region comprising external threading, said threading of said tapered shaft region having said second smaller pitch, said second smaller crest width, and a tapered thread diameter decreasing in diameter from said first thread diameter, said tapered shaft region further comprising at least one recessed flute; andf) a sharp tip. 2. The bone screw of claim 1, wherein said tip comprises no threading or fluting. 3. The bone screw of claim 1, wherein each of said threadings of said first and second cylindrical shaft regions and said tapered shaft region comprises a forward face and a backward face, and further wherein an angle between said forward face and a central axis of the bone screw is substantially constant throughout each of said threadings of said first and second cylindrical shaft regions and said tapered shaft region. 4. The bone screw of claim 3, wherein said angle is about 50 degrees to about 70 degrees. 5. The bone screw of claim 1, wherein each of said threadings of said first and second cylindrical shaft regions and said tapered shaft region comprises a forward face and a backward face, and further wherein an angle between said backward face and a central axis of the bone screw is substantially constant throughout each of said threadings of said first and second cylindrical shaft regions and said tapered shaft region. 6. The bone screw of claim 5, wherein said angle is about 80 degrees to about 100 degrees. 7. The bone screw of claim 1, further comprising a ramping region between said smooth cylindrical shaft region and said first cylindrical shaft region, wherein said ramping region comprises threading that progressively increases in depth from said smooth cylindrical shaft region to said first cylindrical shaft region, measured from an outer surface of said smooth cylindrical shaft region to a thread crest of said threading of said ramping region, from a first thread depth to a second larger thread depth. 8. The bone screw of claim 7, wherein said ramping region comprises less than one full revolution of threading. 9. The bone screw of claim 1, wherein each of said first thread diameter and said thread diameter of said second cylindrical shaft region is about 3.0 mm to about 5.0 mm. 10. The bone screw of claim 1, wherein said at least one recessed flute comprises three recessed flutes. 11. The bone screw of claim 10, wherein each of said flutes spans an angle of about 90 degrees. 12. The bone screw of claim 1, wherein said first pitch is about 5.0 mm to about 7.0 mm and said second smaller pitch is about 2.0 mm to about 4.0 mm. 13. The bone screw of claim 1, wherein said first crest width is about 0.3 mm to about 0.4 mm and said second smaller crest width is about 0.1 mm to about 0.2 mm. 14. The bone screw of claim 1, wherein shaft diameters of said smooth cylindrical shaft region and said first and second cylindrical shaft regions are substantially equal. 15. The bone screw of claim 1, wherein said screw head has a recessed portion for receiving a tool. 16. The bone screw of claim 1, wherein said bone screw is made of a titanium alloy. 17. The bone screw of claim 1, wherein at least a portion of each of said threadings of said first and second cylindrical shaft regions and said tapered shaft region is sized and shaped to engage with a bone screw hole in an anterior cervical plate. 18. The bone screw of claim 1, wherein at least a portion of said threading of said tapered shaft region has a thread diameter smaller than a bone screw hole in an anterior cervical plate and is adapted to fit through said bone screw hole without engaging said bone screw hole. 19. A bone screw for engaging with a bone screw hole in an anterior cervical plate, comprising: a) a sharp tip;b) a tapered shaft region comprising external threading, wherein a shaft diameter of said tapered shaft region increases in a direction away from said tip, wherein a diameter of at least a portion of said threading of said tapered shaft region is smaller than a diameter of said bone screw hole, and wherein said threading of said tapered shaft region has a first pitch and a first crest width;c) a first cylindrical shaft region comprising external threading, wherein a shaft diameter of said first cylindrical shaft region is smaller than said diameter of said bone screw hole, wherein at least a portion of said threading of said first cylindrical shaft region is sized and shaped larger than said diameter of said bone screw hole to engage with said bone screw hole, wherein said threading of said first cylindrical shaft region has a second pitch greater than said first pitch and a second crest width larger than said first crest width, and wherein said second crest width is adapted to resist shearing when engaging with said bone screw hole;d) a second cylindrical shaft region without external threading to disengage from said bone screw hole upon full insertion, wherein a shaft diameter of said second cylindrical shaft region is smaller than said diameter of said bone screw hole; ande) a screw head, wherein a diameter of said screw head is larger than said diameter of said bone screw hole. 20. The bone screw of claim 19, wherein said tip comprises no threading or fluting. 21. The bone screw of claim 19, wherein said threading of said first cylindrical shaft region comprises a forward face and a backward face, and further wherein an angle between said forward face and a central axis of the bone screw is substantially constant throughout said threading of said first cylindrical shaft region. 22. The bone screw of claim 21, wherein said angle is about 50 degrees to about 70 degrees. 23. The bone screw of claim 19, wherein said threading of said first cylindrical shaft region comprises a forward face and a backward face, and further wherein an angle between said backward face and a central axis of the bone screw is substantially constant throughout said threading of said first cylindrical shaft region. 24. The bone screw of claim 23, wherein said angle is about 80 degrees to about 100 degrees. 25. The bone screw of claim 19, further comprising a ramping region between said second cylindrical shaft region and said first cylindrical shaft region, wherein said ramping region comprises threading that progressively increases in depth from said second cylindrical shaft region to said first cylindrical shaft region, measured from an outer surface of said second cylindrical shaft region to a thread crest of said threading of said ramping region, from a first thread depth to a second larger thread depth. 26. The bone screw of claim 25, wherein said ramping region comprises less than one full revolution of threading. 27. The bone screw of claim 19, wherein a thread diameter of said threading of said first cylindrical shaft region, measured from one crest of said threading to an opposite crest of said threading, is substantially constant along said first cylindrical shaft region. 28. The bone screw of claim 27, wherein said thread diameter of said threading of said first cylindrical shaft region is about 3.0 mm to about 5.0 mm. 29. The bone screw of claim 19, wherein said tapered shaft region further comprises at least one recessed flute. 30. The bone screw of claim 29, wherein said at least one recessed flute comprises three recessed flutes. 31. The bone screw of claim 30, wherein each of said flutes spans an angle of about 90 degrees. 32. The bone screw of claim 19, wherein said shaft diameter of said first cylindrical shaft region is substantially equal to said shaft diameter of said second cylindrical shaft region. 33. The bone screw of claim 19, wherein said screw head has a recessed portion for receiving a tool. 34. The bone screw of claim 19, wherein said bone screw is made of a titanium alloy. 35. An anterior cervical plating system, comprising: a) an anterior cervical plate, comprising at least one hole for receiving a bone screw;b) a bone screw, comprising a head; a body, wherein an unthreaded body region of said body adjacent to said head is unthreaded to disengage from said at least one hole upon full insertion and the rest of said body comprises a cylindrical shaft region of said body having a first body diameter and a tapered shaft region having a tapered diameter decreasing from said first body diameter, wherein said cylindrical shaft region comprises external threading having a first pitch and a first crest width and said tapered shaft region comprises external threading having a second pitch smaller than said first pitch and a second crest width smaller than said first crest width; and a tip;c) wherein a diameter of said head is larger than a diameter of said at least one hole, further wherein said first body diameter of said body is smaller than said diameter of said at least one hole, further wherein at least a portion of said external threading of said cylindrical shaft region has a diameter larger than said diameter of said at least one hole, and wherein at least another portion of said external threading of said tapered shaft region has a diameter smaller than said diameter of said at least one hole;d) wherein said portion of said external threading of said cylindrical shaft region having said diameter larger than said diameter of said at least one hole engages with said at least one hole when said bone screw is rotated through said at least one hole, and wherein said first crest width is adapted to resist shearing when engaging with said at least one hole; ande) wherein said unthreaded body region is positioned within said at least one hole when said bone screw has been fully inserted in said at least one hole.