Bone anchor head extender
A pedicle screw tulip head extender. The extender can include an upper body portion joined to a lower body portion. The upper body portion can have two opposing arms extending upwardly from a curved lower surface to define a substantially U-shaped interior channel having a first channel axis, the curved lower surface defining an access opening extending through the upper body portion in a direction generally perpendicular to the first channel axis. The lower body portion can extend downwardly as a protrusion from the upper body portion and can be joined to the upper body portion and can have first and second sides, the first and second sides being substantially planar and parallel and separated by an interior portion, the first and second sides defining a protrusion height and a protrusion width. A screw can be disposed in the interior portion and have external threads defining a thread diameter greater than the protrusion width.
1. A spinal fixation system, the system comprising:
a pedicle screw including a shank and a tulip head connected to an end of the shank, the tulip head including a first arm, a second arm, and a tulip head channel defined by and between the first and second arms;
a pedicle screw tulip head extender including an upper body portion joined to a lower body portion,
i. the upper body portion having two opposing arms extending upwardly from a curved lower surface to define a substantially U-shaped interior channel having a first channel axis, the curved lower surface defining an access opening extending through the upper body portion in a direction generally perpendicular to the first channel axis,
ii. the lower body portion extending downwardly as a protrusion from the upper body portion and joined to the upper body portion and having first and second sides, the first and second sides being substantially planar and parallel and separated by an interior portion, the first and second sides defining a protrusion height and a protrusion width, and
iii. a screw disposed in the interior portion and having external threads defining a thread diameter greater than the protrusion width,
wherein the lower body portion of the pedicle screw tulip head extender is configured to be disposed within the tulip head channel.
2. The spinal fixation system of claim 1 , wherein the lower body portion is substantially a U-shaped protrusion.
3. The spinal fixation system of claim 1 , wherein the first and second sides are substantially U-shaped.
4. The spinal fixation system of claim 1 , wherein the two opposing arms each comprise complementary first interior threads for receiving a set screw.
5. The spinal fixation system of claim 1 , wherein the screw comprises a driving portion accessible through the access opening.
6. The spinal fixation system of claim 1 , wherein the upper body portion comprises a pocket for engaging with a rod reducing tool.
7. The spinal fixation system of claim 1 , further comprising a pedicle screw, the pedicle screw comprising a tulip head, wherein the lower body portion is secured in the tulip head.
8. The spinal fixation system of claim 1 , further comprising a pedicle screw, the pedicle screw comprising a tulip head and interior threads, wherein the external threads of the lower body portion engage the interior threads in the tulip head.
9. The spinal fixation system of claim 1 , further comprising a spinal rod configured to be disposed within the U-shaped interior channel.
10. The spinal fixation system of claim 1 , further comprising an instrument.
11. The spinal fixation system of claim 10 , wherein the instrument is a rod reducer.
12. The spinal fixation system, comprising a mounting rod having a first end and a second end, the mounting rod being generally straight at the first end and defining a central rod axis disposed at a first elevation, the mounting rod being generally turned at an angle on the second end, and having disposed on the second end a rod securing body portion comprising two opposing arms each including a portion of interior threads and extending from a curved lower surface defining a substantially U-shaped interior channel that can have a first channel axis disposed at a second elevation above the first elevation; and
a pedicle screw including a shank and a tulip head connected to an end of the shank, the tulip head including a first arm, a second arm, and a tulip head channel defined by and between the first and second arms;
wherein a portion of the mounting rod is configured to be disposed within the tulip head channel.
13. The spinal fixation system of claim 12 , wherein the mounting rod has a cylindrical cross section.
14. The spinal fixation system of claim 12 , wherein the mounting rod is turned at an angle of about 90 degrees.
15. The spinal fixation system of claim 12 , wherein the rod securing body portion comprises a pocket for engaging with a rod reducing tool.
16. The spinal fixation system of claim 12 , wherein the first channel axis is in a same plane as the central rod axis.
17. The spinal fixation system of claim 12 , wherein the first channel axis is in a plane that is substantially perpendicular to the plane of the central rod axis.
18. The spinal fixation system of claim 12 , further comprising a spinal rod configured to be disposed within the U-shaped interior channel.
19. The spinal fixation system of claim 18 , further comprising a set screw configured to engage the interior threads.
20. The spinal fixation system of claim 12 , further comprising an instrument.