Pedicle fixation system

1. A pedicle fixation system, comprising:

a first fastener, the first fastener including a first head at a proximal end, a first shank extending distally from the first head along a first fastener axis and a channel extending along a skew axis, the skew axis being transverse to the first axis and the channel having a channel diameter perpendicular to the skew axis, wherein the channel extends into a shoulder spaced apart from the head, said shoulder extending radially outwards from the first fastener relative to the first axis; and

a second fastener extending through the channel, the second fastener including a second shank extending along a second fastener axis, at least a distal part of the second shank having a second fastener diameter perpendicular to the second fastener axis, the second fastener diameter being smaller than the channel diameter.

2. The pedicle fixation system of claim 1 , wherein the first fastener includes a generally spherical first head.

3. The pedicle fixation system of claim 2 , wherein the channel extends from an opening in the first head.

4. The pedicle fixation system of claim 2 , comprising a coupling element that includes a pocket shaped to pivotally couple to the first head.

5. The fastener of claim 4 , wherein the coupling element includes a track shaped to couple to a rod.

6. The pedicle fixation system of claim 1 , wherein a majority of the first shank has a generally oval shaped axial cross section relative to the first fastener axis.

7. The pedicle fixation system of claim 6 , wherein the generally oval shaped cross section has a width to thickness ratio of at least 4:3.

8. The pedicle fixation system of claim 1 , wherein:

the first fastener includes a cavity at a proximal end of the channel and a shelf located between the cavity and the channel; and

the second fastener includes a second head having a second head diameter that is greater than an inner diameter of the shelf.

9. The pedicle fixation system of claim 1 , wherein the first fastener comprises:

a platform between the first head and the first shank that extends in a radial direction perpendicular to the first axis; and

a neck between the first head and the platform, the neck having a smaller radius perpendicular to the first axis than the first head and the platform.

10. The pedicle fixation system of claim 9 , wherein the first fastener includes at least one shoulder that extends to a radially outermost point distal of the neck and tapers radially inward from the radially outermost point to the first shank.

11. The pedicle fixation system of claim 10 , wherein the at least one shoulder includes a series of notches on a radially outer surface.

12. The fastener of claim 1 , wherein the first fastener is a first nail.

13. The fastener of claim 12 , wherein the second fastener is a second nail.

14. A method installing a pedicle fixation system, comprising:

inserting a first fastener into a vertebral body in a first direction; and

inserting a second fastener in a second direction transverse to the first direction through a channel of the first fastener and into the vertebral body such that the second fastener secondarily fastens the first fastener to the vertebral body, wherein a head of the second fastener is seated within a cavity at a proximal end of the channel and a planar surface is located between the cavity and the channel.

15. The method of claim 14 , wherein the step of inserting the first fastener includes hammering the first fastener into the vertebral body.

16. The method of claim 14 , wherein the step of inserting the second fastener includes hammering the second fastener into the vertebral body.

17. The method of claim 14 , comprising:

hammering a third fastener into a second vertebral body;

attaching coupling elements to the first and third fasteners; and

inserting a rod through the coupling elements such that the first and third fasteners are coupled to the rod.