Spinal fixation system having locking and unlocking devices for use with a multi-planar, taper lock screw

1. A taper lock screw comprising:

a screw including a shaft and a superiorly positioned screw head;

an inner housing supporting the screw head of the screw and including an inner surface, an outer surface, and an uppermost portion;

an outer housing including an inner surface, an outer surface, and an uppermost portion, the inner surface of the outer housing circumferentially disposed around, and in contact with, at least a portion of the outer surface of the inner housing, the outer housing slidably movable relative to the inner housing to selectively secure a connecting rod within the inner housing and transition the taper lock screw between an unlocked position and a locked position, the inner surface of the outer housing and the outer surface of the inner housing defining a gap therebetween, wherein the gap has a first dimension in the unlocked position and a larger dimension in the locked position, and wherein there is relative flexing movement between the outer housing and the inner housing in response to the transition of the taper lock screw between the unlocked and locked positions; and

an annular flange projecting outwardly from the uppermost portion of the outer housing, the annular flange having an uppermost portion, uppermost portions of the connecting rod and the flange being substantially coplanar when the taper lock screw is in the locked position.

2. The taper lock screw of claim 1 , wherein the flange is positioned to overhang a circumferentially defined annular gripping groove that is configured to facilitate grasping contact of a grasping tool for facilitating locking of the taper lock screw.

3. The taper lock screw of claim 1 , wherein the flange is positioned to overhang an annular gripping groove circumferentially defined in the outer surface of at least a portion of the outer housing.

4. The taper lock screw of claim 1 , wherein an articulation recess is defined in a lower portion of the inner housing, and wherein the articulation recess retains the screw head of the screw within the inner housing while enabling the screw head to rotate within the articulation recess.

5. The taper lock screw of claim 4 , wherein the articulation recess includes at least one contact surface positioned against the screw head.

6. The taper lock screw of claim 4 , wherein the inner housing defines a rod slot in the uppermost portion of the inner housing, the rod slot adapted to receive the connecting rod, the rod slot and the articulation recess being coaxially aligned relative to a longitudinal axis defined through the inner housing that extends through the uppermost portion of the inner housing and the lower portion of the inner housing.

7. The taper lock screw of claim 1 , wherein the outer housing is slidable relative to the inner housing to contact the inner housing with sufficient compressive force to enable the inner housing to contact and secure the connecting rod within the inner housing.

8. The taper lock screw of claim 1 , wherein the outer housing is positionable relative to the inner housing to compress the outer housing against the inner housing to transition the taper lock screw to a partially locked position for sufficiently locking the taper lock screw while enabling movement of the connecting rod within the inner housing.

9. The taper lock screw of claim 1 , wherein the uppermost portion of the flange and the uppermost portion of the connecting rod are substantially coplanar with the uppermost portion of the inner housing in the locked position of the taper lock screw.

10. The taper lock screw of claim 1 , wherein the uppermost portion of the flange and the uppermost portion of the connecting rod are substantially coplanar with the uppermost portion of the outer housing in the locked position of the taper lock screw.

11. The taper lock screw of claim 1 , wherein the uppermost portion of the connecting rod is substantially coplanar with the uppermost portion of the inner housing in the locked and unlocked positions of the taper lock screw.

12. The taper lock screw of claim 1 , wherein at least one of the outer housing and the inner housing is configured to flex in response to the transition of the taper lock screw between the unlocked and locked positions.

13. The taper lock screw of claim 1 , wherein the gap is an enclosed space between the inner and outer housings.

14. A taper lock screw comprising:

a screw including a shaft and a superiorly positioned screw head;

an inner housing supporting the screw head of the screw and including an inner surface, an outer surface, and an uppermost portion;

an outer housing including an inner surface, an outer surface, and an uppermost portion, the inner surface of the outer housing circumferentially disposed around, and in contact with, at least a portion of the outer surface of the inner housing, the outer housing slidably movable relative to the inner housing to selectively secure a connecting rod within the inner housing and transition the taper lock screw between an unlocked position and a locked position, the inner surface of the outer housing and the outer surface of the inner housing defining a gap therebetween; and

an annular flange projecting outwardly from the uppermost portion of the outer housing, the annular flange having an uppermost portion, uppermost portions of the connecting rod and the flange being substantially coplanar when the taper lock screw is in the locked position, the annular flange having a diameter greater than a largest diameter of the outer housing.

15. The taper lock screw of claim 14 , wherein an articulation recess is defined in a lower portion of the inner housing, the articulation recess retaining the screw head of the screw within the inner housing while enabling the screw head to rotate within the articulation recess.

16. The taper lock screw of claim 15 , wherein the inner housing defines a rod slot in the uppermost portion of the inner housing, the rod slot adapted to receive the connecting rod, the rod slot and the articulation recess being coaxially aligned relative to a longitudinal axis defined through the inner housing that extends through the uppermost portion of the inner housing and a lower portion of the inner housing.

17. The taper lock screw of claim 14 , wherein the uppermost portion of the flange and the uppermost portion of the connecting rod are substantially coplanar with the uppermost portion of the inner housing in the locked position of the taper lock screw.

18. The taper lock screw of claim 14 , wherein the outer housing is positionable relative to the inner housing to compress the outer housing against the inner housing to transition the taper lock screw to a partially locked position for sufficiently locking the taper lock screw while enabling movement of a connecting rod within the inner housing.

19. The taper lock screw of claim 14 , wherein the annular flange projects outwardly from an uppermost portion of the outer surface of the outer housing.

20. The taper lock screw of claim 14 , wherein the gap is an enclosed space between the inner and outer housings.