Intervertebral stabilization device incorporating dampers

• US 5,540,688 A
• Filed: 03/08/1994
• Issued: 07/30/1996
• Est. Priority Date: 05/30/1991
• Status: Expired due to Term

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Societe PSI
• Inventors: Navas, Fernand
• Primary Examiner(s): Isabella, David J.
• Application Number:
  US08/207,259
• Time in Patent Office: 875 Days
• Field of Search: 623/16, 623/17, 623/18, 606/61, 606/75
• US Class Current: 606/266
• CPC Class Codes: A61B 17/7004 with a cross-section which varies along its length A61B17/7019 takes precedence
• CPC Class Codes: A61B 17/7005 Parts of the longitudinal elements, e.g. their ends, being specially adapted to fit in the screw or hook heads
• CPC Class Codes: A61B 17/7031 made wholly or partly of flexible material
• CPC Class Codes: A61B 17/7046 the screws or hooks being mobile in use relative to the longitudinal element A61B17/702, A61B17/7035 take precedence
• CPC Class Codes: A61B 2017/606 with resilient spring element
• CPC Class Codes: A61F 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: F16F 3/087 Units comprising several springs made of plastics or the like material F16F1/40, F16F1/545 take precedence
• CPC Class Codes: Y10S 606/908 Bioabsorbable material

Abstract

An intervertebral stabilization device is disclosed, made in the form of a damper adapted to resist elastically, on the one hand, an elongation and, on the other hand, an axial compression without buckling, as well as of at least two implants anchored on two adjacent vertebrae.

Claims

1. An intervertebral stabilization device to stabilize the movement between at least two vertebrae of a patient'"'"'s spine which are positioned on opposite sides of a spinal disc, said device comprising, two anchoring elements each having means to be anchored to adjacent (vertebrate) vertebrae and a free end, a dampening element for dampening elongation of the spine during either axial tension or compression thereof, and said dampening element configured to extend generally exteriorly of the spinal disc and between said free ends of said anchoring elements, said dampening element including opposite ends, and locking means for securing said opposite ends to said free ends of said anchoring elements so that said dampening element works against said free ends to dampen elongation of the spine during either axial tension or compression of the spine.

2. The device of claim 1, wherein said dampening element has an elongated body, said body having an enlarged central portion and said opposite (enlarged) ends being enlarged, and a reduced neck portion joining each of said enlarged ends to opposite ends of said central portion.

16. The device of claim 1, wherein the dampening element is made of two material components.

17. The device of claim 16, wherein a first of said material components is pre-stressed in extension and the other of said material components is prestressed in compression.

18. The device of claim 17, wherein said first material component is in the form of a dumb-bell having a central rod portion and outer enlarged portions forming said opposite ends of said dampening element, and said other material component is in the form of a sleeve which surrounds said rod portion and which sleeve is placed in compression by said outer enlarged portions.

19. The device of claim 17, in which said first material portion is in the form of an elastic envelope defining a cavity therein and said other material component is in the form of a block of elastic material placed in compression within said envelope.

20. The device of claim 17, in which said first material component includes a central element, said second material component being in the form of a sleeve surrounding said central element, a pair of opposing sleeve means surrounding said sleeve and extending inwardly toward one another and forming an annular space therebetween, and an O-ring means positioned within said annular space.

3. An intervertebral stabilization device for stabilizing the movement between at least two vertebrae which are positioned on opposite sides of a spinal disc, said device comprising:

two anchoring elements each having means to be anchored to adjacent vertebrae, a dampening element configured to be positioned and extending between and connected to said anchoring elements, said dampening element having an elongated body, said body having a central portion and opposite enlarged ends, each anchoring element including a socket means at one end thereof for receiving one of said enlarged ends, each of said socket means having a concave bottom surface shaped for close cooperation with said enlarged ends, securing means for retaining said enlarged ends, within said socket means, and said dampening element capable of resisting elastic elongation during either axial tension or compression of the spine.

4. The device of claim 3, wherein said socket means includes a tapped hole and a notch which opens laterally thereof, and said securing means includes a threaded end piece having a hemispherical base, said end piece being threadingly received within said tapped hole.

5. The device of claim 4, wherein said socket means includes two generally opposing notches therein, and at least one of the enlarged ends of said dampening element is hemispherical in configuration.

6. The device of claim 4, including a reduced neck portion between each of said enlarged ends and said central position, and a rigid sleeve means surrounding each of said reduced neck portions of said dampening element.

7. The device of claim 6, wherein the dampening element is made of a bio-compatible elastomer.

8. The device of claim 6, wherein the dampening element is made of two material components.

9. The device of claim 6, wherein said central portion of said elongated body has an elliptical shape in longitudinal cross-section.

10. The device of claim 6, wherein said central portion of said elongated body is asymmetrical.

11. The device of claim 8, wherein a first of said material components is pre-stressed in extension and the other of said material components is pre-stressed in compression.

12. The device of claim 11, wherein said first material component is in the form of a dumb-bell having a central rod portion and outer enlarged portions and said other material component is in the form of a sleeve which surrounds said rod portion and which sleeve is placed in compression by said outer enlarged portions.

13. The device of claim 11, in which said first material portion is in the form of an elastic envelope defining a cavity therein and said other material component is in the form of a block of elastic material placed in compression within said envelope.

14. The device of claim 11, in which said first material component includes a central element, said second material component being in the form of a sleeve surrounding said central element, a pair of opposing sleeve means surrounding said sleeve and extending inwardly toward one another and forming an annular space therebetween, and an O-ring means positioned within said annular space.

15. The device of claim 14, wherein the O-ring is made of a bio-compatible material which is resistant to compressive forces.