Apparatus and method for dynamic vertebral stabilization

• US 20060189983A1
• Filed: 03/22/2005
• Published: 08/24/2006
• Est. Priority Date: 02/22/2005
• Status: Active Grant

• Current Assignee: Stryker European Operations Holdings, LLC (Stryker Corporation)
• Original Assignee: Medicinelodge, Inc (Nelso Antolotti)
• Inventors: Dever, Joel, Fallin, T. Wade, Gerbec, Daniel E.
• Granted Patent: US 7,361,196 B2
• Time in Patent Office: Days
• US Class Current: 606/250
• CPC Class Codes: A61B 17/7007 Parts of the longitudinal elements, e.g. their ends, being specially adapted to fit around the screw or hook heads
• CPC Class Codes: A61B 17/7025 with a sliding joint
• CPC Class Codes: A61B 17/7028 the flexible part being a coil spring
• CPC Class Codes: A61B 17/7052 of variable angle or length

Abstract

A posterior vertebral stabilizer has a resilient member such as a linear spring, which operates in tension and compression. The resilient member may be kept straight by a stabilization rod extending through the spring, or by a telescoping assembly that encases the resilient member. The ends of the stabilizer are attachable to pedicles of adjacent vertebrae so that the stabilizer adds stiffness to control flexion and extension of the vertebrae. Two such stabilizers may be used, and may be connected together by a crosslink designed to limit relative rotation of the stabilizers. Thus, the stabilizers may restrict axial rotation and lateral bending between the vertebrae, while permitting stiffened flexion and extension. Such stabilizers help provide the stiffness of a healthy intervertebral disc. In the event that fusion of the joint becomes necessary, a set screw or other component may be used to further restrict flexion and extension.

Claims

1. A stabilization system for controlling relative motion between a first vertebra and a second vertebra, the stabilization system comprising:

a first stabilizer comprising;

a resilient member configured to be coupled to extend along a path to transmit tension and compression between the first and second vertebrae; and

a first member having a substantially rigid construction, the first member extending along the path to keep the path substantially straight.

2. The stabilization system of claim 1, wherein the first stabilizer comprises a second member that slidably engages the first member such that the first and second members cooperate to keep the path substantially straight.

3. The stabilization system of claim 2, wherein the second member telescopically engages the first member.

4. The stabilization system of claim 3, wherein the first and second members are hollow, wherein the resilient member is positioned within a cavity defined by engagement of the first and second members.

5. The stabilization system of claim 1, wherein the first member comprises an end attachable to a pedicle of one of the first vertebra and the second vertebra.

6. The stabilization system of claim 5, wherein the end is attachable to the pedicle such that the end can rotate about at least one axis with respect to the pedicle after attachment of the end to the pedicle.

7. The stabilization system of claim 5, further comprising a second stabilizer comprising:

a second resilient member configured to be coupled to extend along a second path to transmit tension and compression between the first and second vertebrae; and

a second member having a substantially rigid construction, the second member extending along the second path to keep the second path substantially straight;

wherein the second member comprises a second end attachable to a second pedicle of one of the first vertebra and the second vertebra such that the first and second stabilizers are attachable in a generally symmetrical manner across a sagittal plane of the first and second vertebrae.

8. The stabilization system of claim 1, wherein the resilient member comprises a helical spring.

9. The stabilization system of claim 8, wherein the helical spring comprises a resilient portion and an end attachable to a pedicle of one of the first vertebra and the second vertebra, wherein the resilient portion and the end are integrally formed with each other.

10. The stabilization system of claim 1, wherein the first member is substantially coaxial with the resilient member.

11. The stabilization system of claim 10, wherein the resilient member comprises a resilient portion having a bore, wherein the first member extends through the bore along at least an entire length of the resilient member.

12. The stabilization system of claim 1, wherein the first stabilizer further comprises a locking component positionable to lock the first stabilizer to substantially prevent extension of the second vertebra with respect to the first vertebra.

13. The stabilization system of claim 12, wherein the locking component is configured to cooperate with the first stabilizer to substantially prevent all relative motion of the first and second vertebrae.

14. The stabilization system of claim 1, further comprising a crosslink comprising:

a first end coupled to the first stabilizer; and

a second end extending from the first stabilizer, wherein the second end is substantially secured with respect to one of the first and second vertebrae to restrict axial rotation of the first vertebra with respect to the second vertebra.

15. A method for controlling relative motion between a first vertebra and a second vertebra, the method comprising:

exposing at least a portion of the first and second vertebrae;

positioning a resilient member to extend along a path to transmit tension and compression between the first and second vertebrae; and

positioning a first member having a substantially rigid construction to extend along the path to keep the path substantially straight.

16. The method of claim 15, further comprising positioning a second member in telescopic engagement with the first member to extend along the path such that the first and second members cooperate to keep the path substantially straight, wherein the first and second members are hollow, wherein the resilient member is positioned within a cavity defined by engagement of the first and second members.

17. The method of claim 15, wherein the first member comprises an end, the method further comprising attaching the end to a pedicle of one of the first vertebra and the second vertebra.

18. The method of claim 17, wherein attaching the end to the pedicle comprises enabling the end to rotate about at least one axis with respect to the pedicle after attachment of the end to the pedicle.

19. The method of claim 17, further comprising:

positioning a second resilient member to extend along a second path to transmit tension and compression between the first and second vertebrae; and

positioning a second member having a substantially rigid construction to extend along the second path to keep the second path substantially straight;

wherein positioning the second member comprises attaching a second end of the second member to a second pedicle of one of the first vertebra and the second vertebra such that the first and second members are attachable in a generally symmetrical manner across a sagittal plane of the first and second vertebrae.

20. The method of claim 15, wherein the resilient member comprises a helical spring comprising a resilient portion and an end integrally formed with the resilient portion, wherein positioning the first resilient member comprises attaching the end to a pedicle of one of the first vertebra and the second vertebra.

21. The method of claim 15, wherein the first member is substantially coaxial with the resilient member, wherein the resilient member comprises a resilient portion having a bore, wherein the first member extends through the bore along at least an entire length of the resilient member.

22. The method of claim 15, wherein the resilient member and the first member are incorporated into a first stabilizer, the method further comprising:

coupling a first end of a crosslink to the first stabilizer; and

substantially securing a second end of the crosslink with respect to one of the first and second vertebrae such that the second end extends from the stabilizer to restrict axial rotation of the first vertebra with respect to the second vertebra.