Adjustable height pedicle screw
Described herein is a pedicle screw for use in the thoracolumbar spine where the height can be adjusted intra-operatively before or after installation member of the longitudinal member. The pedicle screws with adjustable height may be made with a monoaxial or polyaxial configuration. The height of the pedicle screw can be lengthened or shortened.
1. A variable height pedicle screw for spinal fixation, comprising:
a longitudinal screw having an external threaded portion, a variable height engagement ramp disposed as an angled top surface located above the threaded portion and an internal threading; and
an adjustable height component having a through-opening and an angled bottom surface, the adjustable height component disposed on top of the variable height engagement ramp in slidable contact with the angled top surface, the adjustable height component adapted to be adjustably affixed to the longitudinal screw, and be axially adjusted intraoperatively relative to the longitudinal screw; and
a tightening screw received in the through-opening and in threading engagement with the internal threading of the longitudinal screw so as to affix the longitudinal screw to the adjustable height component,
a lug capable of being adjusted for forced rotation and height adjustment of the adjustable height component,
wherein the angled bottom surface and the angled top surface are in non-threaded contact and slidable with respect to each other to adjust a height of the adjustable height component.
2. The pedicle screw of claim 1 , wherein the height of the adjustable height component is adapted to be adjusted intraoperatively before or after installation of the longitudinal screw.
3. The pedicle screw of claim 1 , wherein the tightening screw includes a polyaxial screw to affix the adjustable height component to the longitudinal screw.
4. The pedicle screw of claim 1 , wherein the adjustable height component includes an internal threading, the pedicle screw further comprising a rod compression screw having an external threading adapted to be threadingly coupled to the internal threading of the adjustable height component so as to affix a rod to the adjustable height component.
5. The pedicle screw of claim 1 , wherein the tightening screw has an external polyaxial pivot head, and wherein the adjustable height component includes an internal polyaxial locator adapted to accept the external polyaxial pivot head.
6. The pedicle screw of claim 1 , wherein the variable height engagement ramp has an outer diameter that is substantially equal to an outer diameter of the adjustable height component.
7. The pedicle screw of claim 6 , wherein the variable height engagement ramp is positioned at an upper end of the longitudinal screw.
8. The pedicle screw of claim 7 , wherein the adjustable height component includes a positive stop configured to engage a portion of variable height engagement ramp and adapted to set a minimum height of the adjustable height component.
9. The pedicle screw of claim 1 , wherein the longitudinal screw has a smooth or threaded shank for allowing the adjustable height component to be moved co-axially with respect to the longitudinal screw.
10. A variable height pedicle screw for spinal fixation, comprising:
a longitudinal screw having an external threaded portion, a variable height engagement ramp disposed as an angled top surface located above the threaded portion and an internal threading; and
an adjustable height component having a through-opening and an angled bottom surface, the adjustable height component disposed on top of the variable height engagement ramp in slidable contact with the angled top surface, the adjustable height component adapted to be adjustably affixed to the longitudinal screw, and be axially adjusted intraoperatively relative to the longitudinal screw, the adjustable height component being in a U-shape having first and second opposing extensions each having an internal threading, the internal threading of both the first and second extensions adapted to threadingly receive a rod compression screw to affix a rod to the adjustable height component; and
a tightening screw received in the through-opening and in threading engagement with the internal threading of the longitudinal screw so as to affix the longitudinal screw to the adjustable height component,
a lug capable of being adjusted for forced rotation and height adjustment of the adjustable height component,
wherein the angled bottom surface and the angled top surface are in non-threaded contact and slidable with respect to each other to adjust a height of the adjustable height component.
11. The pedicle screw of claim 10 , wherein the tightening screw includes a polyaxial screw to affix the adjustable height component to the longitudinal screw.
12. The pedicle screw of claim 10 , wherein the tightening screw has an external polyaxial pivot head, and wherein the adjustable height component includes an internal polyaxial locator adapted to accept the external polyaxial pivot head.
13. The pedicle screw of claim 10 , wherein the adjustable height component includes a positive stop configured to engage a portion of variable height engagement ramp and adapted to set a minimum height of the adjustable height component.