Pedicle screw assembly

• US 6,488,681 B2
• Filed: 01/05/2001
• Issued: 12/03/2002
• Est. Priority Date: 01/05/2001
• Status: Expired due to Term

• Current Assignee: Stryker European Operations Holdings, LLC (Stryker Corporation)
• Original Assignee: Stryker Spine SA
• Inventors: Martin, Greg, Kelly, William J., Crozet, Yves
• Primary Examiner(s): Philogene, Pedro
• Application Number:
  US09/755,846
• Publication Number:
  US 20020091386A1
• Time in Patent Office: 697 Days
• Field of Search: 606/61, 606/69, 606/60, 606/70, 606/71, 606/72, 606/73, 606/78, 606/53, 411/433, 411/911
• US Class Current: 606/278
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass
• CPC Class Codes: A61B 17/7037 wherein pivoting is blocked when the rod is clamped
• CPC Class Codes: A61B 17/7082 for driving, i.e. rotating, screws or screw parts specially adapted for spinal fixation, e.g. for driving polyaxial or tulip-headed screws driving other bone screws A61B17/8875
• CPC Class Codes: A61B 2017/564 Methods for bone or joint treatment
• CPC Class Codes: G06Q 10/107 Computer-aided management of electronic mailing [e-mailing]

Abstract

A stabilizing assembly includes a fastener having an upper end and a lower end, a head at the upper end, and at least one anchoring element extending between the upper and lower ends. The head includes a center, an underside including a first radial surface and a top side including a second radial surface. The first radial surface of the head defines a first radius from the center of the head and the second radial surface defines a second radius from the center of the head, the first radius being greater than the second radius. The assembly also includes a coupling element having an upper end and a lower end, the coupling element including a rod receiving opening extending from the upper end thereof being adapted to receive a stabilizing rod, a bore extending through the lower end of the coupling element for receiving the fastener, and a conical-shaped seat adjacent the lower end of the coupling element adapted to engage the first radial surface of the head when the fastener is positioned in the bore. A locking element associated with the coupling element is adapted to apply a force upon a stabilizing rod positioned in the rod receiving opening. As a force is applied to a stabilizing rod, the rod in turn, engages the second radial surface at the top side of the head for forcing the underside of the head against the conical-shaped seat of the coupling element so as to prevent further pivotal and rotational movement of the fastener and the coupling element relative to one another. In certain embodiments, the fastener may be a screw fastener having screw threads. In other embodiments, the fastener may include a hook.

Claims

1. A stabilizing assembly comprising:

a fastener having an upper end and a lower end, a head at the upper end, and at least one anchoring element between the upper and lower ends thereof;

said head including a center, an underside including a first radial surface and a top side including a second radial surface, wherein said first radial surface defines a first radius from the center of said head and said second radial surface defines a second radius from the center of said head, the first radius being greater than the second radius; and

a coupling element having an upper end and a lower end, said coupling element including a rod receiving opening adapted to receive a stabilizing rod, a bore extending through the lower end of said coupling element for receiving said fastener, and a conical-shaped seat adjacent the lower end of said coupling element, wherein the first radial surface of said head is engagable with the conical-shaped seat when said fastener is positioned in the bore.

2. The stabilizing assembly as claimed in claim 1, further comprising:

a locking element associated with said coupling element to apply a force upon a stabilizing rod positioned in said rod receiving opening, wherein said stabilizing rod is in direct contact with and applies a force upon the second radial surface of said head for forcing the first radial surface of said head against the conical-shaped seat for preventing further pivotal and rotational movement of said fastener and said coupling element relative to one another.

3. The assembly as claimed in claim 1, wherein said fastener is a screw fastener, and wherein the at least one anchoring element comprises screw threads extending between the upper and lower ends thereof.

4. The assembly as claimed in claim 1, wherein the at least one anchoring element comprises a hook at the lower end of said fastener.

5. The assembly as claimed in claim 3, wherein said head includes at least one groove extending from the top surface toward the underside thereof, said at least one groove being adapted to receive a driver for inserting said fastener into bone.

6. The assembly as claimed in claim 5, wherein said at least one groove extends in a direction substantially parallel to the longitudinal axis of said screw fastener.

7. The assembly as claimed in claim 5, wherein said at least one groove includes a plurality of grooves.

8. The assembly as claimed in claim 7, further comprising a driver comprising a shaft having a lower end and a plurality of prongs extending from the lower end of the shaft and insertable into said grooves of said screwhead.

9. The assembly as claimed in claim 8, wherein said driver includes external threads provided on the shaft.

10. The assembly as claimed in claim 9, wherein said coupling element includes internal threads, and wherein the external threads of said driver are engagable with the internal threads of said coupling element.

11. The assembly as claimed in claim 1, wherein said coupling element includes internal threads extending from the upper end toward the lower end thereof, said coupling element including an annular lip having a diameter between the internal threads and the conical-shaped seat of the coupling element, and wherein the diameter of said annular lip is less than twice the first radius of said head.

12. The assembly as claimed in claim 1, wherein the center of said screwhead is in substantial alignment with the longitudinal axis of said screw fastener.

13. The assembly as claimed in claim 1, wherein said coupling element has threads extending from the upper end thereof.

14. The assembly as claimed in claim 13, wherein the threads of said coupling element are internal threads formed on an interior surface of said coupling element.

15. The assembly as claimed in claim 14, wherein said locking element comprises a set screw having external threads for threadably engaging the internal threads of said coupling element.

16. The assembly as claimed in claim 1, wherein the threads of said coupling element are exterior threads formed on an exterior surface of said coupling element.

17. The assembly as claimed in claim 16, wherein said locking element comprises a nut having internal threads for threadably engaging the exterior threads of said coupling element.

18. The assembly as claimed in claim 1, wherein said coupling element includes an exterior surface having one or more notches formed therein.

19. The assembly as claimed in claim 18, wherein said coupling element includes one or more cuts between the rod-receiving opening and the exterior surface thereof for minimizing the width of said coupling element.

20. The assembly as claimed in claim 1, wherein said fastener is a screw fastener having screw threads and a neck having a reduced diameter between the head of said fastener and the screw threads.

21. The assembly as claimed in claim 20, wherein the neck of said screw fastener has a concave surface.

22. The assembly as claimed in claim 1, wherein said stabilizing assembly is made from a material selected from the group consisting on titanium and stainless steel.

23. A stabilizing assembly comprising:

a fastener having an upper end and a lower end, a head at the upper end, and at least one anchoring element between the upper and lower ends for anchoring the fastener to bone;

said head including a center, an underside including a first radial surface and a top side including a second radial surface, said first radial surface defining a first radius from the center of said head and said second radial surface defining a second radius from the center of said head, the first radius being greater than the second radius; and

a coupling element having an upper end and a lower end, said coupling element including a rod receiving opening adapted to receive a stabilizing rod, a bore extending through the lower end of said coupling element for receiving said fastener, and a seat adjacent the lower end of said coupling element engagable with the first radial surface of said head when said fastener is positioned in the bore, wherein the seat of said coupling element is substantially conical-shaped and includes inwardly tapering sidewalls.

24. The stabilizing assembly as claimed in claim 23, further comprising:

a locking element associated with said coupling element, said locking element being adapted to apply a force upon a stabilizing rod positioned in said rod receiving opening, wherein said stabilizing rod in turn directly engages the second radial surface at the top side of said head for forcing the underside of said head against the conical-shaped seat for preventing further pivotal and rotational movement of said screw fastener and said coupling element relative to one another.

25. The stabilizing assembly as claimed in claim 23, wherein said fastener is a screw fastener having screw threads, the at least one anchoring element including the screw threads.

26. The stabilizing assembly as claimed in claim 23, wherein said fastener includes a hook, the at least one anchoring element including the hook.

27. A stabilizing assembly comprising:

a fastener having an upper end and a lower end, a head at the upper end, and at least one anchoring element extending between the upper and lower ends, said head including an underside having a first radial surface; and

a coupling element having an upper end and a lower end, said coupling element including a rod receiving opening adapted to receive a stabilizing rod, a bore extending through the lower end of said coupling element for receiving said fastener, and a conical-shaped seat adapted to engage the first radial surface of said head when said fastener is positioned in the bore.

28. The stabilizing assembly as claimed in claim 27, further comprising:

a locking element associated with said coupling element, said locking element being adapted to apply a force against a stabilizing rod positioned in said rod receiving opening, said stabilizing rod in turn applying a direct force to a top side of said head for forcing the first radial surface of said head against the conical-shaped seat of said coupling element.

29. The stabilizing assembly as claimed in claim 28, wherein the top side of said head includes a second radial surface, and wherein said first radial surface defines a first radius from a center of said head and said second radial surface defines a second radius from the center of said head, the first radius being greater than the second radius.

30. The assembly as claimed in claim 29, wherein the center of said head is in substantial alignment with a longitudinal axis of said fastener.

31. The assembly as claimed in claim 30, wherein said fastener is a screw fastener, the at least one anchoring element including screw threads extending between the upper and lower ends of said fastener.

32. The assembly as claimed in claim 27, wherein said coupling element has threads extending from the upper end thereof and said locking element includes a threaded set screw having threads adapted to mesh with the threads of said coupling element.

33. A bone fastener having an upper end and a lower end, said bone fastener comprising:

a head at the upper end thereof; and

at least one bone anchoring element extending between the upper and lower ends of said fastener, wherein said head includes a center, an underside having a first radial surface with a first radius from the center, and a top side having a second radial surface with a second radius from the center, wherein the first radius is greater than the second radius, wherein said fastener is insertable into a coupling element having an upper end and a lower end, said coupling element including a rod receiving opening, a bore extending through the lower end of said coupling element for receiving said fastener, and a conical-shaped seat adjacent the lower end of said coupling element being engagable with the first radial surface at the underside of said head when said fastener is positioned in the bore, wherein said inserted screw fastener pivots relative to said coupling element before being locked from further movement relative to said coupling element.

34. The fastener as claimed in claim 33, wherein said fastener comprises a material selected from the group consisting of titanium and stainless steel.

35. The fastener as claimed in claim 33, wherein said fastener includes screw threads extending between the upper and lower ends thereof.

36. The fastener as claimed in claim 33, wherein said fastener includes a hook at the lower end thereof.

37. A stabilizing assembly for use in conjunction with an orthopedic stabilizing rod, said assembly comprising:

a fastener including a lower end insertable into bone and a head at an upper end thereof having a first radial surface with a first radius at an underside of said head and a second radial surface with a second radius at a top side of said head, wherein the first radius is greater than the second radius; and

a coupling element having an upper end and a lower end, said coupling element including a rod receiving opening adapted to receive a stabilizing rod, a bore extending through the lower end of said coupling element for receiving said fastener, and a conical-shaped seat adapted to directly engage the first radial surface at the underside of said head when said fastener is assembled with said coupling element, wherein said fastener and said coupling element are free to pivot and rotate relative to one another before the head of said fastener is locked in said coupling element.

38. The assembly as claimed in claim 37, wherein said coupling element includes an exterior surface having one or more notches formed therein, said notches being engageable for securing said coupling element.

39. The assembly as claimed in claim 37, further comprising a locking element for locking a stabilizing rod in the rod receiving opening of said coupling element, said locking element being associated with said coupling element to force said stabilizing rod against the second radial surface of said head which in turn forces the first radial surface of said head against the conical-shaped seat of said coupling element for preventing said coupling element and said screw fastener from pivoting and rotating relative to one another.

40. The assembly as claimed in claim 37, wherein said fastener includes screw threads extending between the upper and lower ends thereof.

41. The assembly as claimed in claim 37, wherein said fastener includes a hook.

42. A coupling element for a stabilizing assembly comprising:

an upper end and a lower end;

a rod receiving opening adapted to receive a stabilizing rod;

a bore extending through the lower end of said coupling element for receiving a fastener having a head with a first radial surface of a first diameter;

a conical-shaped seat adjacent the lower end of said coupling element adapted to directly engage a radial underside of the head of said fastener;

threads extending from the upper end toward the lower end of said coupling element; and

an annular lip between the threads and the seat of said coupling element, wherein said annular lip has a second diameter that is less than the first diameter of the first radial surface of said head.

43. A coupling element for a stabilizing assembly comprising:

an upper end and a lower end remote therefrom;

a rod receiving opening adapted to receive a stabilizing rod;

said coupling element having an exterior surface and an interior surface defining a central bore extending through the lower end of said coupling element;

a conical-shaped seat adjacent the lower end of said coupling element adapted to directly engage a radial underside of a head of said fastener, wherein said coupling element includes one or more cuts between the rod-receiving opening and the exterior surface thereof for minimizing the width of said coupling element.