Systems and methods for posterior dynamic stabilization of the spine
View Patent ↗Systems and devices for dynamically stabilizing the spine are provided. The systems include a superior component for attachment to a superior vertebra of a spinal motion segment and an inferior component for attachment to an inferior vertebral of a spinal motion segment. The interconnection between the two components enables the spinal motion segment to move in a manner that mimics the natural motion of the spinal motion segment. Methods are also provided for stabilizing the spine and for implanting the subject systems.
1. A system for stabilizing at least one spinal motion segment comprising a superior vertebra and an inferior vertebra, the system comprising:
a superior component configured to couple to the superior vertebra using a first pedicle screw, the superior component comprising a base portion and a strut, the strut having a proximal end coupled to the base portion and a distal end, the distal end having an apposition surface positioned on an exterior surface substantially parallel to a longitudinal axis of the strut;
an inferior component configured to couple to the inferior vertebra using a second pedicle screw, the inferior component comprising a base portion having an apposition surface axially aligned with the inferior component for engaging the apposition surface of the distal end of the strut such that at least the distal end of the strut is offset from the plane substantially bisecting the first and the second pedicle screws, wherein the apposition surface of the base portion is axially aligned with the inferior component such that the apposition surface is substantially offset from a plane substantially bisecting the first and the second pedicle screws, and wherein forward translation of the superior vertebra relative to the inferior vertebra is at least limited; and
a spacer positioned between the two apposition surfaces, wherein the spacer allows translational and/or angular displacement between the two apposition surfaces while maintaining constant apposition between the two apposition surfaces, and wherein the spacer is coupled to both apposition surfaces.
2. The system of claim 1 , wherein the spacer is bonded to both apposition surfaces.
3. The system of claim 1 , wherein the spacer comprises at least two layers wherein a first layer is bonded to the superior apposition surface, the second layer is bonded to the inferior apposition surfaces and the first and second layers are bonded to each other.
4. The system of claim 1 , wherein the spacer is secured between the two apposition surfaces by a pin which extends through the superior apposition surface, the spacer and the inferior apposition surface.
5. The system of claim 1 , wherein the spacer is made of a compliant material wherein the spacer experiences a shearing motion upon movement of the vertebrae.
6. The system of claim 1 , wherein the spacer is unbonded.
7. The system of claim 6 , further comprising a securement mechanism configured to hold the apposition surfaces in an apposed configuration.
8. The system of claim 1 , wherein the spacer is a spring washer.
9. The system of claim 1 , wherein the superior component apposition surface is posteriorly facing and the inferior component apposition surface is anteriorly facing.
10. The system of claim 1 , wherein the apposition surfaces are reciprocally configured such that the superior component apposition surface is received by the inferior component apposition surface.
11. A system for stabilizing at least one spinal motion segment comprising a superior vertebra and an inferior vertebra, the system comprising:
a strut having a proximal end positioned at a superior component and a distal end positioned at an inferior component;
a superior component configured to couple to the superior vertebra using a first pedicle screw, wherein the superior component is configured to adjustably receive the proximal end of the strut wherein the length of a portion of the strut extending inferiorly of the superior component is adjustable;
an inferior component configured to couple to the inferior vertebra using a first pedicle screw, wherein the inferior component comprises a surface for engaging with the distal end of the strut, wherein forward translation of the superior vertebra relative to the inferior vertebra is at least limited; and
a spacer positioned between the distal end of the strut and the engaging surface of the inferior component, wherein the spacer allows translational and/or angular displacement between the two apposition surfaces and maintains constant apposition between the distal end of the strut and the engaging surface, wherein the spacer is secured between the distal end of the strut and the engaging surface of the inferior component by a pin which extends through the distal end of the strut, the spacer and the engaging surface.
12. The system of claim 11 , wherein the spacer is bonded to the distal end of the strut and to the engaging surface.
13. The system of claim 11 , wherein the spacer comprises at least two layers wherein a first layer is bonded to the distal end of the strut, the second layer is bonded to the engaging surface and the first and second layers are bonded to each other.
14. The system of claim 11 , wherein the spacer is made of a compliant material wherein the spacer experiences a shearing motion upon movement of the vertebrae.
15. The system of claim 11 , wherein the proximal end of the strut is connected to the superior component.
16. A method for stabilizing at least one spinal motion segment comprising a superior vertebra and an inferior vertebra, the method comprising:
providing:
a superior component configured to couple to the superior vertebra using a first pedicle screw, the superior component comprising: a base portion and a strut, the strut having a proximal end coupled to the base portion and a distal end, the distal end having an apposition surface positioned on an exterior surface substantially parallel to a longitudinal axis of the strut;
an inferior component configured to couple to the inferior vertebra using a second pedicle screw, the inferior component including a base portion and having an apposition surface for engaging with the superior component apposition surface of the distal end of the strut such that at least the distal end of the strut is offset from the plane substantially bisecting the first and the second pedicle screws, wherein the apposition surface of the base portion is substantially offset from a plane substantially bisecting the first and the second pedicle screws, and wherein forward translation of the superior vertebra relative to the inferior vertebra is at least limited; and
a spacer positioned between the two apposition surfaces, wherein the spacer maintains constant apposition between the two apposition surfaces;
coupling the superior component to the superior vertebra using the first pedicle screw;
coupling the inferior component to the inferior vertebra using the second pedicle screw; and
allowing translational and/or angular displacement between the two apposition surfaces while maintaining substantial apposition between the apposition surfaces by coupling the apposition surfaces together.
17. The method of claim 16 , wherein maintaining substantial apposition comprises bonding the apposition surfaces together.
18. The method of claim 16 , wherein maintaining substantial apposition comprises securing the two surfaces together.
19. A system for stabilizing at least one spinal motion segment comprising a superior vertebra and an inferior vertebra, the system comprising:
a superior component configured to couple to the superior vertebra using a first pedicle screw, the superior component comprising a base portion and a strut, the strut having a proximal end coupled to the base portion and a distal end, the distal end having an apposition surface positioned on an exterior surface substantially parallel to a longitudinal axis of the strut;
an inferior component configured to couple to the inferior vertebra using a second pedicle screw, the inferior component comprising a base portion having an apposition surface axially aligned with the inferior component for engaging the apposition surface of the distal end of the strut such that at least the distal end of the strut is offset from the plane substantially bisecting the first and the second pedicle screws, wherein the apposition surface of the base portion is axially aligned with the inferior component such that the apposition surface is substantially offset from a plane substantially bisecting the first and the second pedicle screws, and wherein forward translation of the superior vertebra relative to the inferior vertebra is at least limited; and
a spacer positioned between the two apposition surfaces, wherein the spacer allows translational and/or angular displacement between the two apposition surfaces while maintaining constant apposition between the two apposition surfaces, and wherein the spacer is secured between the two apposition surfaces by a pin which extends through the superior apposition surface, the spacer and the inferior apposition surface.
20. The system of claim 19 , wherein the spacer is bonded to both apposition surfaces.
21. The system of claim 19 , wherein the spacer comprises at least two layers wherein a first layer is bonded to the superior apposition surface, the second layer is bonded to the inferior apposition surfaces and the first and second layers are bonded to each other.
22. The system of claim 19 , wherein the spacer is made of a compliant material wherein the spacer experiences a shearing motion upon movement of the vertebrae.
23. The system of claim 19 , wherein the spacer is a spring washer.
24. The system of claim 19 , wherein the superior component apposition surface is posteriorly facing and the inferior component apposition surface is anteriorly facing.