Spine distraction implant

• US 8,128,663 B2
• Filed: 06/27/2007
• Issued: 03/06/2012
• Est. Priority Date: 01/02/1997
• Status: Expired due to Fees

• Current Assignee: Kyphon SARL (Medtronic Plc)
• Original Assignee: Kyphon SARL (Medtronic Plc)
• Inventors: Zucherman, James F., Hsu, Ken Y., Fallin, T. Wade, Klyce, Henry A.
• Primary Examiner(s): Robert, Eduardo C
• Assistant Examiner(s): HOFFMAN, MARY C
• Application Number:
  US11/768,962
• Publication Number:
  US 20080033445A1
• Time in Patent Office: 1,714 Days
• Field of Search: 606247-249, 606/75, 606/324, 606/330, 606280-299, 606/70, 606/71, 623 1711- 1716, 243/36, 243/39, 245/31
• US Class Current: 606/249
• CPC Class Codes: A61B 17/66 Alignment, compression or distraction mechanisms
• CPC Class Codes: A61B 17/7047 Clamps comprising opposed elements which grasp one vertebra between them
• 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: A61K 31/37 Coumarins, e.g. psoralen

Abstract

A spine distraction implant alleviates pain associated with spinal stenosis and facet arthropathy. The implant may provide a spinal extension stop while allowing freedom of spinal flexion. The implant includes a central portion and first, second, third, and fourth arms that extend away from the central portion to form two generally oppositely facing saddles. For some versions, one arm is longer than the other arms. For some versions, all the arms are of different length, with one of the arms being longer than the other three, and one of the arms being shorter than the other three.

Claims

1. A spinal implant apparatus, comprising:

a central portion;

first, second, third, and fourth arms extending away from the central portion;

a first saddle formed by a first intersection of the central portion with two of the arms;

the first saddle opening in a first direction;

the two arms forming the first saddle including the first arm;

a second saddle formed by a second intersection of the central portion with the other two of the arms;

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

each of the arms extending a different length from the central portion;

the first arm longer than all the other arms;

the fourth arm shorter than all the other arms;

wherein a plane extends through a center of the first and second saddles;

wherein when viewed normal to the plane;

the profile of the apparatus at the first and second intersections of the arms with the central portion is curved;

wherein one of the arms has a tapered shape such that a thickness of a base of the arm, disposed closest to the central portion, is greater than a thickness of a tip of the arm, disposed farthest from the central portion, the thicknesses being measured in a direction parallel to the plane.

2. The apparatus of claim 1 wherein the first arm tapers in a direction away from the central portion.

3. The apparatus of claim 1:

wherein a theoretical line bisects the saddles and defines lateral sides of the implant;

wherein two of the arms are disposed on a first lateral side of the implant and the other two arms are disposed on the opposite second lateral side of the implant;

wherein the arm on the same lateral side of the implant as the first arm, and forming the second saddle, is shorter than the other arm forming the second saddle.

4. The apparatus of claim 1 wherein the portions of the central portion forming the first and second saddles are generally parallel.

5. The apparatus of claim 1 wherein one of the arms forming the first saddle comprises a curved section forming a concave recess, with the recess oriented generally perpendicular to the first direction.

6. The apparatus of claim 1 wherein the central portion of the implant comprises a bore, the bore extending generally perpendicular to the arms.

7. The apparatus of claim 1 wherein the central portion of the implant has as modulus of elasticity approximately twice a modulus of elasticity of bone.

8. A spinal implant, comprising:

a central portion;

first, second, third, and fourth arms extending away from the central portion;

a first saddle formed by a first section of the central portion and the first arm and another one of the arms;

the first saddle opening in a first direction;

a second saddle formed by a second section of the central portion and the other two of the arms;

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

the first arm longer than all the other arms;

wherein a theoretical plane extends through a center of the first and second saddles;

wherein both the first and second saddles have a curved profile where the arms intersect the central portion when viewed normal to the theoretical plane such that two of the arms extend upward and two of the arms extend downward and the saddles have their widest appearance;

wherein one of the arms has a tapered shape such that a thickness of a base of the arm, disposed closest to the central portion, is greater than a thickness of a tip of the arm, disposed farthest from the central portion, the thicknesses being measured in a direction parallel to the plane.

9. The spinal implant of claim 8 wherein the first arm tapers in a direction away from the central portion.

10. The spinal implant of claim 8 wherein the first and second sections of the central portion forming the first and second saddles are generally parallel.

11. The spinal implant of claim 8 wherein one of the arms forming the first saddle comprises a curved section forming a concave recess, with the recess oriented generally perpendicular to the first direction.

12. The spinal implant of claim 8 wherein the central portion of the implant comprises a bore, the bore extending generally perpendicular to the arms.