Inter-vertebral disc prosthesis for lumbar rachis through posterior surgery thereof

• US 20030220695A1
• Filed: 03/26/2003
• Published: 11/27/2003
• Est. Priority Date: 09/26/2000
• Status: Abandoned Application

• Current Assignee: Orthoplex LLC
• Original Assignee: Lionel Charles Sevrain
• Inventors: Sevrain, Lionel C.
• Application Number:
  US10/396,725
• Publication Number:
  US 20030220695A1
• Time in Patent Office: Days
• US Class Current: 623/17.16
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2002/444 for replacing the nucleus pulposus

Abstract

A prosthetic inter-vertebral disc for positioning in an inter-somatic space between a pair of adjacent vertebrae (V) and within a natural annulus fibrosus (12) or a remaining portion thereof, comprises a flexible elongated outer annulus member (22) and an expandable inner nucleus member (24). The outer annulus member (22) is adapted to be introduced into the inter-somatic space through a tenotomy opening (16) and to follow an inside wall of the natural annulus fibrosus (12) such as to form a closed loop therewithin with the loop defining a chamber (20). The inner nucleus member (24) is adapted to be introduced in a dehydrated state into the inter-somatic space also through the tenotomy opening (16) and within the outer annulus member (22), and to then be hydrated so as to extend in the chamber (20) peripherally up to the outer annulus member (22). Both the outer annulus member (22) and the inner nucleus member (24) are hydrogels. The outer annulus member (22) is biased outwardly when being introduced in the inter-somatic space such that it follows the inside wall of the natural annulus fibrosus (12). A free end of the outer annulus member (22) extends outwardly of the closed loop and into the tenotomy opening for sealing the same. A method of installing the prosthetic disc is also disclosed.

Claims

1. A prosthetic inter-vertebral disc for positioning in an inter-somatic space between a pair of adjacent vertebrae and within a natural annulus fibrosus or a remaining portion thereof, comprising an elongated outer annulus member and an inner nucleus member, said outer annulus member being flexible and being adapted to be introduced into the inter-somatic space through a tenotomy opening and to follow an inside wall of the natural annulus fibrosus such as to form a substantially closed loop therewithin, said loop defining a chamber, said inner nucleus member being adapted to be introduced into the inter-somatic space through the tenotomy opening and within said outer annulus member and being adapted to extend in said chamber peripherally up to said outer annulus member.

2. A prosthetic inter-vertebral disc as defined in claim 1, wherein said outer annulus member and said inner nucleus member are respectively made of first and second hydrogels.

3. A prosthetic inter-vertebral disc as defined in claim 1, wherein when said prosthetic disc has been installed, said closed loop comprises a pair of ends of said outer annulus member that overlap in the inter-somatic space and block the tenotomy opening for preventing hydrogel nucleus herniation.

4. A prosthetic inter-vertebral disc as defined in claim 1, wherein said outer annulus member is biased outwardly when being introduced in the inter-somatic space such that it applies on the inside wall of the natural annulus fibrosus.

5. A prosthetic inter-vertebral disc as defined in claim 1, wherein said inner nucleus member is adapted to be introduced through the tenotomy opening into the chamber in a dehydrated position thereof, and to then be hydrated such as to expand up to an inside surface of said outer annulus member.

6. A prosthetic inter-vertebral disc as defined in claim 2, wherein said outer annulus member is made of a first hydrogel which is non-degradable and the polymer network of which is chemically reticulated by covalent bonds.

7. A prosthetic inter-vertebral disc as defined in claim 2, wherein said inner nucleus member is made of a second hydrogel, which is non-biodegradable and the polymer network of which is chemically reticulated by covalent bonds, and which has visco-elastic properties that are similar to those of the natural nucleus pulposus such as to counterbalance or offset the external hydrostatic pressure which is exerted thereon.

8. A method of installing a prosthetic inter-vertebral disc in an inter-somatic space, devoid of a natural nucleus pulposus, between a pair of adjacent vertebrae and within a natural annulus fibrosus or a remaining portion thereof, comprising the steps of:

(a) introducing an elongated flexible outer annulus member into the inter-somatic space through a tenotomy opening such that said outer annulus member follows an inside wall of the natural annulus fibrosus;

(b) introducing an inner nucleus member in a first position thereof through the tenotomy opening and within said outer annulus member; and

(c) displacing said inner nucleus member to a second position thereof such that it extends outwardly up to said outer annulus member.

9. A method as defined in claim 8, wherein said outer annulus member is adapted in step (a) to form a substantially closed loop within the natural annulus fibrosus, said loop defining a chamber, said inner nucleus member being adapted to be positioned in said chamber.

10. A method as defined in claim 8, wherein said outer annulus member and said inner nucleus member are respectively made of first and second hydrogels.

11. A method as defined in claim 9, wherein a free end of said outer annulus member is positioned such as to extend outwardly of said closed loop and into the tenotomy opening for substantially sealing the same.

12. A method as defined in claim 8, wherein said outer annulus member is biased outwardly when being introduced in step (a) in the inter-somatic space such that it follows the inside wall of the natural annulus fibrosus.

13. A method as defined in claim 8, wherein said inner nucleus member, in step (b) , is introduced through the tenotomy opening in a dehydrated position thereof;

and to then be, in step (c), hydrated such as to expand up to an inside surface of said outer annulus member.

14. A method of installing a prosthetic inter-vertebral disc in an inter-somatic space, devoid of a natural nucleus pulposus, between a pair of adjacent vertebrae and within a natural annulus fibrosus or a remaining portion thereof, comprising the steps of:

(a) introducing an elongated flexible outer annulus member into the inter-somatic space through a tenotomy opening and using a mid-portion of said outer annulus member as a leading end until said outer annulus member applies against an inside wall of the natural annulus fibrosus;

(b) introducing an inner nucleus member in a first position thereof through the tenotomy opening and within said outer annulus member; and

(c) displacing said inner nucleus member to a second position thereof such that it extends outwardly up to said outer annulus member.

15. A method as defined in claim 14, wherein said outer annulus member is adapted in step (a) to form a substantially closed loop within the natural annulus fibrosus, said loop defining a chamber, said inner nucleus member being adapted to be positioned in said chamber.

16. A method as defined in claim 14, wherein said outer annulus member and said inner nucleus member are respectively made of first and second hydrogels.

17. A method as defined in claim 14, wherein a pair of ends of said outer annulus member are positioned in an overlapping way in the inter-somatic space such that said closed loop closes off the tenotomy opening for substantially sealing the same.

18. A method as defined in claim 14, wherein said outer annulus member is biased outwardly when being introduced in step (a) in the inter-somatic space such that it applies against the inside wall of the natural annulus fibrosus.

19. A method as defined in claim 14, wherein said inner nucleus member, in step (b), is introduced through the tenotomy opening in a dehydrated position thereof;

and to then be, in step (c), hydrated such as to expand up to an inside surface of said outer annulus member.