Fastening devices, systems, and methods

1. A pedicle bone fastener comprising:

a shaft comprising:

a proximal end;

a distal end; and

a longitudinal axis;

a helical thread disposed about the shaft along the longitudinal axis between the proximal and distal ends of the shaft, the helical thread comprising:

a first undercut surface; and

a second undercut surface, wherein:

the first undercut surface is angled toward one of the proximal end and the distal end of the shaft;

the second undercut surface is angled toward the other one of the proximal end and the distal end of the shaft; and

at least one of the first undercut surface and the second undercut surface comprises a concave crescent shape; and

an integrated attachment feature at the proximal end of the shaft and configured to be adjustably secured to a spinal stabilization implement.

2. The pedicle bone fastener of claim 1 , wherein the integrated attachment feature comprises a polyaxial head having a first semi-spherical surface configured to be polyaxially-adjustably secured to the spinal stabilization implement.

3. The pedicle bone fastener of claim 2 , wherein the spinal stabilization implement comprises a discrete tulip having a second semi-spherical surface configured to engage the first semi-spherical surface of the polyaxial head to polyaxially-adjustably secure the discrete tulip to the polyaxial head at any of a variety of relative orientations.

4. The pedicle bone fastener of claim 3 , wherein the discrete tulip further comprises:

at least one opening; and

a locking member configured to secure a rod receivable through the at least one opening to the discrete tulip.

5. The pedicle bone fastener of claim 1 , wherein the integrated attachment feature comprises an integrated tulip having at least one opening configured to receive at least a part of the spinal stabilization implement therethrough.

6. The pedicle bone fastener of claim 5 , wherein the spinal stabilization implement comprises a rod receivable through the at least one opening of the integrated tulip.

7. The pedicle bone fastener of claim 6 , wherein the integrated tulip further comprises a locking member configured to secure the rod to the integrated tulip.

8. A pedicle fastener stabilization system comprising:

a pedicle bone fastener comprising:

a shaft comprising:

a proximal end;

a distal end; and

a longitudinal axis;

a polyaxial head at the proximal end of the shaft;

a first helical thread disposed about the shaft along the longitudinal axis between the proximal and distal ends of the shaft, the first helical thread comprising a first concave undercut surface oriented toward one of the proximal end and the distal end of the shaft; and

a second helical thread disposed about the shaft adjacent the first helical thread and interposed therebetween, the second helical thread comprising a second concave undercut surface oriented toward the other one of the proximal end and the distal end of the shaft;

a tulip configured to be polyaxially-adjustably secured to the polyaxial head; and

a spinal stabilization rod securable to the tulip.

9. The pedicle fastener stabilization system of claim 8 , wherein the polyaxial head is integrally formed with the pedicle bone fastener.

10. The pedicle fastener stabilization system of claim 9 , wherein the polyaxial head comprises a first semi-spherical surface.

11. The pedicle fastener stabilization system of claim 10 , wherein the tulip comprises a second semi-spherical surface configured to engage the first semi-spherical surface of the polyaxial head to polyaxially-adjustably secure the tulip to the polyaxial head at any of a variety of relative orientations.

12. The pedicle fastener stabilization system of claim 8 , wherein the tulip comprises at least one opening configured to receive the spinal stabilization rod therethrough.

13. The pedicle fastener stabilization system of claim 12 , wherein the tulip comprises a locking member configured to secure the spinal stabilization rod to the tulip.

14. The pedicle fastener stabilization system of claim 8 , wherein a minor diameter of the shaft is constant.

15. A method of implanting a bone fastener assembly comprising:

inserting a bone fastener into a bone, the bone fastener comprising:

a shaft comprising:

a proximal end;

a distal end; and

a longitudinal axis;

a helical thread disposed about the shaft along the longitudinal axis between the proximal and distal ends of the shaft, the helical thread comprising:

a first undercut surface; and

a second undercut surface, wherein:

the first undercut surface is angled toward one of the proximal end and the distal end of the shaft; and

the second undercut surface is angled toward the other one of the proximal end and the distal end of the shaft; and at least one of the first undercut surface and the second undercut surface comprises a concave crescent shape; and

an attachment feature at the proximal end of the shaft configured to be adjustably secured to an implement;

adjusting an orientation of the implement to a selected orientation relative to the attachment feature; and

attaching the implement to the attachment feature at the selected orientation.

16. The method of claim 15 , wherein:

the attachment feature at the proximal end of the shaft is configured to be polyaxially-adjustably secured to the implement; and

adjusting the orientation of the implement to the selected orientation relative to the attachment feature further comprises:

polyaxially adjusting the orientation of the implement to a selected relative orientation, of a plurality of polyaxially-differentiated potential relative orientations, relative to the attachment feature.

17. The method of claim 16 , wherein:

the attachment feature comprises a polyaxial head having a first semi-spherical surface; and

the implement comprises a discrete tulip having a second semi-spherical surface configured to engage the first semi-spherical surface of the polyaxial head to polyaxially-adjustably secure the discrete tulip to the polyaxial head at any of a variety of relative orientations.

18. The method of claim 17 , wherein the discrete tulip comprises:

at least one opening; and

a locking member configured to secure a rod received through the at least one opening to the discrete tulip.

19. The method of claim 15 further comprising:

drilling a pilot hole into the bone; and

inserting the shaft of the bone fastener into the pilot hole.

20. The method of claim 19 further comprising:

tapping a bone thread in the bone to form a tapped bone thread about the pilot hole; and

inserting the helical thread into the tapped bone thread.