Spine distraction implant and method

• US 8,568,455 B2
• Filed: 10/26/2007
• Issued: 10/29/2013
• Est. Priority Date: 01/02/1997
• Status: Expired due to Fees

• Current Assignee: Kyphon SARL (Medtronic Plc)
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: Zucherman, James F., Hsu, Ken Y., Fallin, T. Wade, Klyce, Henry A.
• Primary Examiner(s): Truong, Kevin T
• Assistant Examiner(s): SEVILLA, CHRISTIAN ANTHONY
• Application Number:
  US11/924,884
• Publication Number:
  US 20080045959A1
• Time in Patent Office: 2,195 Days
• Field of Search: 606246-279, 606/228, 606/232, 623 1711- 1716, 623/13.11, 623/13.13, 623/13.14, 292/251, 403 43- 44
• US Class Current: 606/249
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 17/66 Alignment, compression or distraction mechanisms
• CPC Class Codes: A61B 17/7062 Devices acting on, attached to, or simulating the effect of, vertebral processes, vertebral facets or ribs rib fixation devices A61B17/8076; Tools for such devices
• CPC Class Codes: A61B 17/7064 Devices acting on, attached to, or simulating the effect of, vertebral facets; Tools therefor
• CPC Class Codes: A61B 17/7065 Devices with changeable shape, e.g. collapsible or having retractable arms to aid implantation; Tools therefor
• CPC Class Codes: A61B 17/7068 Devices comprising separate rigid parts, assembled in situ, to bear on each side of spinous processes; Tools therefor
• CPC Class Codes: A61B 17/7071 Implants for expanding or repairing the vertebral arch or wedged between laminae or pedicles; Tools therefor
• CPC Class Codes: A61B 2017/00867 shape memory effect for prostheses A61F2210/0014
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61K 31/37 Coumarins, e.g. psoralen
• CPC Class Codes: Y10S 606/91 Polymer

Abstract

A spine distraction implant alleviates pain associated with spinal stenosis and facet arthropathy by expanding the volume in the spine canal and/or neural foramen. The implant provides a spinal extension stop while allowing freedom of spinal flexion.

Claims

1. An apparatus, comprising:

an implant member having a cylindrical portion and a saddle portion, at least a portion of the cylindrical portion configured to be disposed between a pair of adjacent spinous processes, the cylindrical portion having a longitudinal length at a first time and a longitudinal length at a second time when the portion of the cylindrical portion is disposed between the pair of adjacent spinous processes, the longitudinal length at the second time being different than the longitudinal length at the first time, the saddle portion configured to receive a first spinous process from the pair of adjacent spinous processes;

wherein the saddle portion comprises an concave surface facing outwardly away from the cylindrical portion generally parallel to a longitudinal axis of the cylindrical portion and disposed between first and second arms of the saddle;

the first arm having a first passage defined therein extending through the first arm and fully circumscribed thereby;

the second arm having a second passage therein extending through the second arm and fully circumscribed thereby;

the first and second passages disposed transverse to the longitudinal axis of the cylindrical portion;

a tether configured to couple the implant member to the first spinous process;

the tether extending through at least one of the first and second passages;

the cylindrical portion having a longitudinally extending spiral groove disposed along an exterior of the cylindrical portion.

2. The apparatus of claim 1 wherein the longitudinal axis of the cylindrical portion is substantially parallel to a mid line axis defined by the pair of adjacent spinous processes when the portion of the cylindrical portion is disposed between the pair of adjacent spinous processes.

3. The apparatus of claim 1, wherein an outer surface of the cylindrical portion defines at least one opening configured to enhance a flexibility of the cylindrical portion.

4. The apparatus of claim 1, wherein the tether is configured to substantially surround the first spinous process.

5. The apparatus of claim 1, wherein:

a first end of the tether is anchored at the first arm;

a second end of the tether is anchored at the second arm;

a central portion of the tether, between the first and second ends of the tether, is disposed between the first and second arms in spaced relation to the concave surface of the saddle.

6. The apparatus of claim 1, wherein the tether is a first tether, the apparatus further comprising:

a second tether configured to couple the implant member to a second spinous process from the pair of adjacent spinous processes.

7. The apparatus of claim 1, further comprising:

a rigid fastener configured to couple the implant member to a second spinous process from the pair of adjacent spinous processes.

8. The apparatus of claim 1, wherein:

the saddle portion is a first saddle portion; and

the implant member has a second saddle portion configured to receive a second spinous process from the pair of adjacent spinous processes.

9. An apparatus, comprising:

a spacer having a cylindrical portion, a first end portion and a second end portion, the cylindrical portion configured to be disposed between a pair of adjacent spinous processes, the first end portion configured to limit lateral motion of the cylindrical portion relative to a first spinous process from the pair of adjacent spinous processes, the second end portion configured to limit lateral motion of the cylindrical portion relative to a second spinous process from the pair of adjacent spinous processes, an outer surface of the cylindrical portion defining an opening configured to enhance a flexibility of the cylindrical portion;

wherein the first end portion comprises first and second arms;

the first arm having a first passage defined therein extending through the first arm and fully circumscribed thereby;

the second arm haying a second passage therein extending through the second arm and fully circumscribed thereby;

wherein the second end portion comprises third and fourth arms;

the third arm haying a third passage therein extending through the third arm and fully circumscribed thereby;

the fourth arm having a fourth passage therein extending through the fourth arm and fully circumscribed thereby;

a first tether extending through the at least one of first and second passages and configured to couple the spacer to the first spinous process;

a second tether extending through the at least one of third and fourth passages and configured to couple the spacer to the second spinous process;

wherein the first and second arms form a first generally U-shaped saddle opening in a first direction generally parallel to a longitudinal axis of the cylindrical portion;

wherein the third and fourth arms form a second generally U-shaped saddle opening in a second direction generally parallel to the longitudinal axis;

wherein the second direction is generally opposite the first direction.

10. The apparatus of claim 9, wherein the opening defined by the outer surface of the cylindrical portion is a first opening from a plurality of openings.

11. The apparatus of claim 9, wherein at least the cylindrical portion of the spacer is constructed from an elastic material.

12. The apparatus of claim 9, wherein at least the cylindrical portion of the spacer is constructed from a material having a modulus of elasticity corresponding to a modulus of elasticity of a bone.

13. The apparatus of claim 9 wherein the cylindrical portion of the spacer has a first longitudinal length when in a first configuration and a second longitudinal length when in a second configuration, the second length being different than the first length.

14. The apparatus of claim 9 wherein:

the longitudinal axis of the cylindrical portion is substantially parallel to a mid line axis defined by the pair of adjacent spinous processes when the cylindrical portion is disposed between the pair of adjacent spinous processes; and

the cylindrical portion is configured to move between a first configuration and a second configuration when the cylindrical portion is disposed between the pair of adjacent spinous processes, a size of the cylindrical portion along the longitudinal axis when the cylindrical portion is in the first configuration being different than a size of the cylindrical portion along the longitudinal axis when the cylindrical portion is in the second configuration.

16. The apparatus of claim 9, wherein:

a first end of the first tether is coupled to a first side of the first end portion of the spacer;

a second end of the first tether is coupled to a second side of the first end portion of the spacer, the second side opposite the first side; and

a central portion of the first tether is disposed about the first spinous process.

17. The apparatus of claim 9, wherein:

the first end portion of the spacer defines a saddle configured to receive a portion of the first spinous process; and

the second end portion of the spacer defines a saddle configured to receive a portion of the second spinous process.

15. An apparatus, comprising:

a spacer having a cylindrical portion, a first end portion and a second end portion, the cylindrical portion configured to be disposed between a pair of adjacent spinous processes, the first end portion configured to limit lateral motion of the cylindrical portion relative to a first spinous process from the pair of adjacent spinous processes, the second end portion configured to limit lateral motion of the cylindrical portion relative to a second spinous process from the pair of adjacent spinous processes, an outer surface of the cylindrical portion defining an opening configured to enhance a flexibility of the cylindrical portion;

first and second pairs of apertures extending through lateral surfaces of the first and second end portions, respectively;

the first and second pairs of apertures extending transverse to a sagittal plane defined by the spinous processes when the cylindrical portion is disposed between the pair of spinous processes;

a first tether extending through the first pair of apertures and configured to couple the spacer to the first spinous process;

a second tether extending through the second pair of apertures and configured to couple the spacer to the second spinous process;

wherein the first tether is configured to substantially surround the first spinous process.

18. An apparatus, comprising:

a spacer having a cylindrical portion, a first end portion and a second end portion, the cylindrical portion configured to be disposed between a pair of adjacent spinous processes, the first end portion having a first arm and a second side forming a saddle configured to receive a first spinous process from the pair of adjacent spinous processes, the second end portion having a first arm and a second arm forming a saddle configured to receive a second spinous process from the pair of adjacent spinous processes;

the first arm of the first end portion having a first passage defined therein extending through the first arm and fully circumscribed thereby;

the second arm of the first end portion having a second passage therein extending through the second arm and fully circumscribed thereby;

the first arm of the second end portion having a third passage therein extending therethrough and fully circumscribed thereby;

the second arm of the second end portion having a fourth passage therein extending therethrough and fully circumscribed thereby;

a first tether having a first end and a second end;

the first end of the first tether anchored to the first end portion at the first passage;

the second end of the first tether anchored to the first end portion at the second passage;

the first tether configured to couple the spacer to the first spinous process when the spacer is disposed between the pair of adjacent spinous processes;

a second tether having a first end and a second end;

the first end of the second tether anchored to the second end portion at the third passage;

the second end of the second tether anchored to the second end portion at the fourth passage;

the second tether configured to couple the spacer to the second spinous process when the spacer is disposed between the pair of adjacent spinous processes;

the cylindrical portion having longitudinally extending spiral groove disposed along an exterior of the cylindrical portion.

19. The apparatus of claim 18, wherein:

the cylindrical portion is configured to move between a first configuration and a second configuration when the cylindrical portion is disposed between the pair of adjacent spinous processes; and

a size of the cylindrical portion along a longitudinal axis of the cylindrical portion when the cylindrical portion is in the first configuration is different than a size of the cylindrical portion along the longitudinal axis when the cylindrical portion is in the second configuration.

20. The apparatus of claim 18, wherein a longitudinal axis of the cylindrical portion is substantially parallel to a mid line axis defined by the pair of adjacent spinous processes when the cylindrical portion is disposed between the pair of adjacent spinous processes.

21. The apparatus of claim 18, wherein an outer surface of the cylindrical portion defines at least one opening configured to enhance the flexibility of the cylindrical portion.

22. The apparatus of claim 18, wherein the cylindrical portion is constructed from a material having a modulus of elasticity no greater than a modulus of elasticity of a bone.

23. The apparatus of claim 18, wherein the first tether is configured to substantially surround the first spinous process.

24. An implant for spacing apart adjacent first and second spinous processes, comprising:

a first end portion defining first saddle oriented in a first direction and adapted to receive the first spinous process;

a second end portion defining a second saddle adapted to receive the second spinous process;

the second saddle oriented in a second direction generally opposite the first direction;

an intermediate portion variable in length along a longitudinal axis, the intermediate portion disposed between the first and second end portions along the longitudinal axis;

the first saddle having first and second arms each projecting in the first direction generally parallel to the longitudinal axis;

the first saddle further comprising a first concave surface disposed between the first and second arms;

the second saddle having third and fourth arms each projecting in the second direction generally parallel to the longitudinal axis;

the second saddle further comprising a second concave surface disposed between the third and fourth arms;

the intermediate portion having a generally cylindrical cross-section normal to the axis with an internal longitudinal bore defined along the axis within the cross-section;

the intermediate portion having a lateral opening extending from the bore generally radially outwardly to an exterior surface of the intermediate portion for increasing flexibility of the intermediate portion.

25. The implant of claim 24 further comprising a tether coupled to the first saddle at the first and second arms so as to enclose the first saddle for securing the first saddle to the first spinous process with an intermediate portion of the tether disposed in spaced relation to the first concave surface and laterally between the first and second arms.