Pedicle screws and methods of using the same
Pedicle screws that can include a pedicle screw body, housing, plurality of clamps, rod, and set screw are disclosed herein. The clamps may be positioned side by side inside the lower portion of the housing. When the rod and set screw are provided in the housing, the set screw applies a force on the rod and the rod engages the plurality of clamps, causing the clamps to frictionally engage a head of the pedicle screw between the clamps.
1. A pedicle screw comprising:
a threaded screw body having a proximal end and a distal end, the proximal end comprising an enlarged head;
a housing having an upper portion having an upper opening and a lower portion having a lower opening extending along a first axis of the housing, the upper portion being internally threaded and the lower portion having a gradually decreasing dimension toward the lower opening, and a third opening and a fourth opening along a second axis transverse to the first axis adapted to receive an elongated rod;
a plurality of clamps completely separate from each other and positioned side-by-side adjacent the lower portion of the housing, each of the clamps having an upper surface adapted to engage the elongated rod and a lower surface adapted to engage the enlarged head; and
a set screw configured to be received within the internally threaded first portion, wherein the set screw when engaged in the first opening applies a force onto the rod when received in the housing, the rod engaging the plurality of clamps and causing the clamps to frictionally engage the enlarged head between the lower surfaces of the clamps.
2. The pedicle screw of claim 1 , wherein the lower surface adapted to engage the enlarged head comprises a plurality of grooves aligned horizontally on the lower surface.
3. The pedicle screw of claim 1 , wherein the clamps have an upper portion with a cylindrical outer surface and a lower portion with a curved outer surface.
4. The pedicle screw of claim 3 , wherein an outer diameter of the lower portion is less than or about equal to an outer diameter of the upper portion.
5. The pedicle screw of claim 3 , wherein an outer diameter of the lower portion gradually decreases toward a lower end of the lower portion.
6. The pedicle screw of claim 1 , wherein the enlarged head comprises a roughened surface.
7. The pedicle screw of claim 6 , wherein the roughened surface is grooved.
8. The pedicle screw of claim 1 , further comprising a crimp from an outside of the housing to hold the clamps within the housing.
9. A pedicle screw comprising:
a threaded screw body having a proximal end and a distal end, the proximal end comprising an at least partially ball-shaped member;
a housing having an upper portion with an upper opening and a lower portion with a lower opening extending along a first axis of the housing, the upper portion being internally threaded and the lower portion having an internal surface, and a third opening and a fourth opening along a second axis transverse to the first axis adapted to receive an elongated rod;
a plurality of clamps completely separate from each other and positioned side-by-side adjacent the lower portion of the housing, each of the clamps having an upper portion and a lower portion, the lower portion having an outer surface and a ball-shaped inner surface, the outer surface of the lower portion adapted to engage the internal surface of the lower portion of the housing, the upper portion of the clamps adapted to contact the elongated rod, and the ball-shaped inner surface adapted to engage the ball-shaped member; and
a set screw configured to be received within the internally threaded first portion of the housing, wherein the set screw when engaged in the first portion applies a force onto the rod when received in the housing, the rod engaging the plurality of clamps to frictionally engage the ball-shaped member against the ball-shaped inner surface of each of the clamps.
10. The pedicle screw of claim 9 , wherein the ball-shaped inner surface comprises a plurality of grooves aligned horizontally on the ball-shaped inner surface.
11. The pedicle screw of claim 9 , wherein the upper portion of the clamps has a cylindrical outer surface and the outer surface of the lower portion is curved, the upper portion cylindrical outer surface gradually transitioning to the curved outer surface of the lower portion.
12. The pedicle screw of claim 9 , further comprising a crimp from an outside of the housing to hold the clamps within the housing.
13. A pedicle screw comprising:
a threaded screw body having a proximal end and a distal end, the proximal end comprising an at least partially ball-shaped member;
a housing having an upper portion with an upper opening and a lower portion with a lower opening extending along a first axis of the housing, the upper portion being internally threaded and the lower portion having a curved internal surface, and a third opening and a fourth opening along a second axis transverse to the first axis adapted to receive an elongated rod;
a plurality of clamps completely separate from each other and positioned side-by-side adjacent the lower portion of the housing, each of the clamps having an upper portion with a cylindrical outer surface and a lower portion with a curved outer surface and a ball-shaped inner surface, the curved outer surface of the lower portion adapted to engage the curved internal surface of the lower portion of the housing, the upper portion of the clamps adapted to contact the elongated rod, and the ball-shaped inner surface adapted to engage the ball-shaped member; and
a set screw configured to be received within the internally threaded first portion of the housing, wherein the set screw when engaged in the first portion applies a force onto the rod when received in the housing, the rod engaging the plurality of clamps to frictionally engage the ball-shaped member against the ball-shaped inner surface of each of the clamps.
14. The pedicle screw of claim 13 , wherein the ball-shaped inner surface comprises a plurality of grooves.
15. The pedicle screw of claim 14 , wherein the plurality of grooves are aligned horizontally on the ball-shaped inner surface.
16. The pedicle screw of claim 13 , wherein a diameter of the ball-shaped member is less than an inner diameter of the lower opening of the housing.
17. The pedicle screw of claim 13 , comprising no more than two clamps.
18. The pedicle screw of claim 13 , wherein each clamp has an upper portion with an indentation shaped to receive the rod.
19. The pedicle screw of claim 13 , further comprising a crimp from an outside of the housing to hold the clamps within the housing.
20. The pedicle screw of claim 13 , wherein a radius of curvature of the curved outer surface of the lower portion of each of the clamps is different from a radius of curvature of the curved internal surface of the lower portion of the housing.