Pivotal bone anchor assembly with receiver having vertical tool engagement groove
A receiver of a bone anchor includes a base and a pair of upright arms extending upward from the base to define an open channel for receiving an elongate rod, with the upright arms having opposed interior surfaces with a discontinuous guide and advancement structure formed therein and side outer faces opposite the opposed interior surfaces extending downward across the base to a bottom of the receiver. A horizontally-elongated upper tool engaging groove is formed into the side outer face of each upright arm that extends to at least a front face or back face of the upright arm and that includes a downwardly-facing upper surface, an upwardly-facing lower surface, and an outwardly-facing inner surface. A vertical tool-engaging groove is also formed into the side outer face of each upright arm that extends downward from a top surface of the upright arm through to a level below the lower surface of the upper tool engaging groove.
1. A receiver of a bone anchor, the receiver being configured to accept a rod that is locked in the receiver via a closure top, the receiver comprising:
a receiver body having a longitudinal axis, a base, and a pair of upright arms extending upwardly from the base to define an open channel configured for receiving the rod, the open channel having a transverse axis perpendicular to the longitudinal axis and opening through front and back outer faces of the receiver body, the upright arms having opposed interior surfaces, top surfaces defining a top of the receiver body, and a discontinuous guide and advancement structure formed into the opposed interior surfaces adjacent the top surfaces, the receiver body having side outer faces opposite the opposed interior surfaces of each upright arm and extending downward across the base to a bottom of the receiver body;
a horizontally-elongated upper tool engaging groove formed into the side outer face of each upright arm a distance below the top surface and extending to at least one of the front outer face and the back outer face to define an upper portion of the upright arm above the upper tool engaging groove, each upper tool engaging groove including a downwardly-facing upper surface, an upwardly-facing lower surface, and an outwardly-facing inner surface; and
a vertical tool-engaging groove formed into the side outer face of each upright arm, the vertical tool-engaging groove extending downward from the top surface of each upright arm through the upper portion and to a level below the upper and lower surfaces of the upper tool engaging groove.
2. The receiver of claim 1 , wherein the vertical tool-engaging groove extends downward through the outwardly facing inner surface of the upper tool engaging groove.
3. The receiver of claim 1 , wherein the side outer faces of the receiver body further comprise cylindrically-curved surfaces.
4. The receiver of claim 3 , wherein the upper tool engaging groove of each upright arm is radiused to extend at least partially around a periphery of the upright arm.
5. The receiver of claim 1 , wherein the upper tool engaging groove of each upright arm extends to both the front and back outer faces of the receiver body.
6. The receiver of claim 5 , wherein the vertical tool-engaging groove extends downward through a center portion of the upper tool engaging groove.
7. The receiver of claim 1 , wherein the downwardly-facing upper surface of each upper tool engaging groove further comprise an undercut or dovetail feature to inhibit splaying of a tool off of the receiver body.
8. The receiver of claim 1 , wherein the upwardly-facing lower surface of each upper tool engaging groove extends outwardly and downwardly from a lower corner of the outwardly-facing inner surfaces.
9. The receiver of claim 1 , wherein the upper tool engaging grooves are located entirely above the rod when the rod is locked in the open channel by the closure top.
10. A bone anchor assembly comprising the receiver of claim 1 and further comprising a bone anchor extending downward from the receiver body or configured to extend downward from the receiver body.
11. The bone anchor assembly of claim 10 , wherein the bone anchor is a shank having a head portion configured to be pivotally received within the base of the receiver body and an anchor portion opposite the head portion with a helically wound thread configured for attachment to a bone of a patient.
12. The bone anchor assembly of claim 11 , wherein the shank is cannulated by having a central opening extending along an entire length thereof.
13. The bone anchor assembly of claim 11 and further comprising an insert having a lower surface configured to apply pressure to the head portion of the shank and an upper surface configured for engagement by one of the rod or a tool.
14. The bone anchor assembly of claim 13 , wherein the insert is configured to be top loaded into the receiver body.
15. The bone anchor assembly of claim 13 , wherein the receiver body includes an internal non-threaded recess spaced above a lower opening in the receiver body with a generally downwardly-facing surface configured to overlappingly receive a generally upwardly-facing surface on the insert.
16. The bone anchor assembly of claim 15 , wherein the internal non-threaded recess is radiused.
17. The bone anchor assembly of claim 13 , wherein the insert includes a central bore configured to allow the passage of a driving tool to engage an internal drive aperture formed in the head portion of the shank.
18. The bone anchor assembly of claim 17 , wherein the vertical tool-engaging grooves extend downwardly below the upper tool engaging grooves to intersect with side apertures extending through the thickness of the upright arms below the discontinuous guide and advancement structure.
19. The bone anchor assembly of claim 13 and further comprising the tool, wherein the vertical tool-engaging grooves are configured to slidingly receive the tool that is configured to engage and downwardly compress the insert without engaging the rod, so as to apply a locking pressure on the head portion of the shank to independently lock a position of the shank with respect to the receiver body without the rod being positioned in the open channel.
20. The bone anchor assembly of claim 10 and further comprising the rod and the closure top, and wherein the closure top includes a continuous guide and advancement structure formed into an outer sidewall surface configured to engage the discontinuous guide and advancement structure formed into the opposed interior surfaces of the upright arms to capture the rod within the open channel of the receiver.
21. The bone anchor assembly of claim 20 , wherein the closure top is positioned inwardly in the receiver body with respect to the upper tool engaging grooves to engage the rod.
22. A receiver of a bone anchor, the receiver being configured to accept a rod that is locked in the receiver via a closure top, the receiver comprising:
a receiver body having a longitudinal axis, a base, and a pair of upright arms extending upwardly from the base to define an open channel configured for receiving the rod, the open channel having a transverse axis perpendicular to the longitudinal axis and opening through front and back outer faces of the receiver body, the upright arms having opposed interior surfaces, top surfaces defining a top of the receiver body, and a discontinuous guide and advancement structure formed into the opposed interior surfaces adjacent the top surfaces, the receiver body having side outer faces opposite the opposed interior surfaces of each upright arm and extending downward across the base towards a bottom of the receiver body;
a horizontally-elongated upper tool engaging groove formed into the side outer face of each upright arm a distance below the top surface and extending to at least one of the front outer face and the back outer face to define an upper portion of the upright arm above the upper tool engaging groove, each upper tool engaging groove including a downwardly-facing upper surface, an upwardly-facing lower surface, and an outwardly-facing inner surface; and
a vertical tool-engaging groove formed into the side outer face of each upright arm, the vertical tool-engaging groove extending downward from the top surface of each upright arm through the upper portion to a level below the upper and lower and inner surfaces of the upper tool engaging groove.
23. The receiver of claim 22 , wherein the side outer faces of the receiver body further comprise cylindrically-curved surfaces.
24. The receiver of claim 23 , wherein the upper tool engaging groove of each upright arm is radiused to extend at least partially around a periphery of the upright arm.
25. The receiver of claim 22 , wherein the upper tool engaging grooves are located entirely above the rod when the rod is locked in the open channel by the closure top.
26. A bone anchor assembly comprising the receiver of claim 22 and further comprising a bone anchor extending downward from the receiver body or configured to extend downward from the receiver body.
27. The bone anchor assembly of claim 26 , wherein the bone anchor is a shank having a head portion configured to be pivotally received within the base of the receiver body and an anchor portion opposite the head portion with a helically wound thread configured for attachment to a bone of a patient.
28. The bone anchor assembly of claim 27 and further comprising an insert having a lower surface configured to engage the head portion of the shank and an upper surface configured for engagement by one of the rod or a tool.
29. The bone anchor assembly of claim 28 and further comprising the tool, wherein the vertical tool-engaging grooves are configured to slidingly receive the tool that is configured to engage and downwardly compress the insert without engaging the rod, so as to apply a locking pressure on the head portion of the shank to independently lock a position of the shank with respect to the receiver body without the rod being positioned in the open channel.
30. The bone anchor assembly of claim 26 and further comprising the rod and the closure top, and wherein the closure top includes a continuous guide and advancement structure formed into an outer sidewall surface configured to engage the discontinuous guide and advancement structure formed into the opposed interior surfaces of the upright arms to capture the rod within the open channel of the receiver.
31. A receiver of a bone anchor, the receiver being configured to accept a rod that is locked in the receiver via a closure top, the receiver comprising:
a receiver body having a longitudinal axis, a base, and a pair of upright arms extending upwardly from the base to define an open channel configured for receiving the rod, the open channel having a transverse axis perpendicular to the longitudinal axis and opening through front and back outer faces of the receiver body, the upright arms having opposed interior surfaces, top surfaces defining a top of the receiver body, and a discontinuous guide and advancement structure formed into the opposed interior surfaces adjacent the top surfaces, the receiver body having side outer surfaces opposite the opposed interior surfaces of each upright arm and extending downward across the base towards a bottom of the receiver body;
a horizontally-elongated upper tool engaging groove formed into the side outer surface of each upright arm a distance below the top surface and extending to at least one of the front outer face and the back outer face to define an upper portion of the upright arm above the upper tool engaging groove, each upper tool engaging groove including a downwardly-facing upper surface, an upwardly-facing lower surface, and an outwardly-facing inner surface; and
a vertical tool-engaging groove formed into the side outer surface of each upright arm, the vertical tool-engaging groove extending downward from the top surface of each upright arm through the upper portion so as to communicate with the upper tool engaging groove.
32. The receiver of claim 31 , wherein the side outer faces of the receiver body further comprise cylindrically-curved surfaces.
33. The receiver of claim 32 , wherein the upper tool engaging groove of each upright arm is radiused to extend at least partially around a periphery of the upright arm.
34. The receiver of claim 31 , wherein the bottom of the receiver body further comprises a substantially flat annular surface perpendicular to the longitudinal axis of the receiver body.
35. The receiver of claim 31 , wherein the upper tool engaging grooves are located entirely above the rod when the rod is locked in the open channel by the closure top.
36. A bone anchor assembly comprising the receiver of claim 31 and further comprising a bone anchor extending downward from the receiver body or configured to extend downward from the receiver body.