Dual Spring Posterior Dynamic Stabilization Device With Elongation Limiting Elastomers

• US 20100211104A1
• Filed: 04/29/2009
• Published: 08/19/2010
• Est. Priority Date: 02/13/2009
• Status: Active Grant

• Current Assignee: DePuy Synthes Products LLC (Johnson & Johnson)
• Original Assignee: DePuy Synthes Products LLC (Johnson & Johnson)
• Inventors: Flaherty, Kevin, Fanger, Jonathan, Moumene, Missoum, Afshari, Payman
• Granted Patent: US 8,641,734 B2
• Time in Patent Office: Days
• US Class Current: 606/257
• CPC Class Codes: A61B 17/7028 the flexible part being a coil spring
• CPC Class Codes: A61B 17/7031 made wholly or partly of flexible material

Abstract

A Posterior Dynamic Stabilization device that comprises a dual lead titanium spring, a polymer core component disposed within the spring, and a bone anchor attachment feature, wherein the dual rod comprises an intermediate spring portion comprising first and second springs, each spring having a helical intermediate portion, the helical intermediate portions oriented to form a double helix.

Claims

1. A posterior dynamic stabilization device comprising;

a) a first end attachment feature adapted for attachment to a first bone anchor,

b) a second end attachment feature adapted for attachment to a second bone anchor,

c) an intermediate spring portion comprising first and second springs, each spring having a helical intermediate portion, the helical intermediate portions oriented to form a double helix.

2. The device of claim 1, wherein the double helix defines an internal space and the device further comprises:

d) a polymer core located at least within the internal space of the double helix.

3. The device of claim 1 wherein the first and second end attachment features each comprise an inner face, an outer face, and a blind recess opening onto the inner face to form a hollow bore.

4. The device of claim 3 wherein each spring further comprises a first end and a second end, wherein the first end of each spring is attached to the first end attachment feature, and the second end of each spring is attached to the second end attachment feature.

5. The device of claim 4 wherein the first end of each spring is located in the hollow bore of the first end attachment feature, and the second end of each spring is located in the hollow bore of the second end attachment feature.

6. The device of claim 1 wherein the first end attachment feature comprises a first rod, and the second end attachment feature comprises a second rod.

7. The device of claim 6 wherein the first rod has a first length and the second rod has a second length, wherein the first length is greater than the second length.

8. The device of claim 7 wherein the first length is at least two times greater than the second length.

9. The device of claim 1, wherein the double helix defines an internal space and the device further comprises:

d) a polymer core located within the internal space of the double helix and extending through the double helix.

10. The device of claim 9 wherein the first end attachment feature comprises a first rod, and the second end attachment feature comprises a second rod, and wherein the polymer core and the first rod define a first gap therebetween, and wherein the polymer core and the second rod define a second gap therebetween.

11. The device of claim 1 wherein each spring further comprises a first spring end having a first diameter and a second end having a second diameter, wherein each helical intermediate portion has a third diameter, and the third diameter is greater than the first and second diameters.

12. The device of claim 1 wherein each spring further comprises a first spring end having a first diameter, the device further comprising:

d) a solid component having a threaded outer surface, the solid component located within the first spring end.

13. The device of claim 1 wherein each spring further comprises a first end having a linear rod configuration.

14. The device of claim 13 wherein the linear rod fits into a hollow bore of the first end attachment feature.

15. The device of claim 14 wherein the first end attachment feature comprises first and second semi-cylinders, and wherein the device further comprises:

e d) a set screw passing through each of the first and second semi-cylinders.

16. The device of claim 1 wherein each spring further comprises a first end having a linear rod configuration, wherein the linear rod fits into a hollow bore of the first end attachment feature, and wherein the device further comprises:

d) a set screw passing through the first attachment feature to lock the linear rod.

17. The device of claim 16 wherein an end of the screw is frustoconical.

18. The device of claim 1 further comprising:

d) a compression cap disposed between the first end attachment feature and the intermediate spring portion.

19. A multi-level posterior dynamic stabilization device comprising;

a) a first end attachment feature adapted for attachment to a first bone anchor,

b) a second end attachment feature adapted for attachment to a second bone anchor,

c) an intermediate attachment feature adapted for attachment to a third bone anchor,

d) a first intermediate spring portion located between the first end attachment feature and the intermediate attachment feature, and comprising first and second springs, each spring having a helical intermediate portion, the helical intermediate portions oriented to form a first double helix, and

e) a second intermediate spring portion located between the second end attachment feature and the intermediate attachment feature, and comprising third and fourth springs, each spring having a helical intermediate portion, the helical intermediate portions oriented to form a second double helix.