Intervertebral disc nucleus prosthesis

• US 6,402,784 B1
• Filed: 01/07/2000
• Issued: 06/11/2002
• Est. Priority Date: 07/10/1997
• Status: Expired due to Term

• Current Assignee: Aberdeen Orthopaedic Developments Limited
• Original Assignee: Aberdeen Orthopaedic Developments Limited
• Inventors: Wardlaw, Douglas
• Primary Examiner(s): Willse, David H.
• Assistant Examiner(s): GHERBI, SUZETTE JAIME J
• Application Number:
  US09/462,442
• Time in Patent Office: 886 Days
• Field of Search: 623/17.12, 623/17.16, 623/8, 623/17.11
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/8891 at its periphery
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• 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 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30187 D-shaped or half-disc-shaped
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30583 filled with hardenable fluid, e.g. curable in-situ
• CPC Class Codes: A61F 2002/30929 having at least two superposed coatings
• CPC Class Codes: A61F 2002/30971 Laminates, i.e. layered products
• CPC Class Codes: A61F 2002/444 for replacing the nucleus pulposus
• CPC Class Codes: A61F 2002/4495 having a fabric structure, e.g. made from wires or fibres
• CPC Class Codes: A61F 2002/4627 with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2210/0085 hardenable in situ, e.g. epoxy resins
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0034 D-shaped
• CPC Class Codes: A61F 2240/001 Designing or manufacturing processes

Abstract

The present invention provides a prosthetic cover (12) shaped to form a replacement nucleus pulposis (56) for an intervertebral disc (50), said cover comprising a permeable layer of an immunologically neutral material terminating in a valve structure (16) to allow the introduction of a hydrogel material (14); characterized in that a transudative material is disposed on the intended inner face of the cover to allow a through flow of low molecular weight materials only.

Claims

1. In a valve structure adapted for use with a prosthetic device, said structure comprising a body with a longitudinal bore therethrough, said body comprising means for the attachment of a prosthetic cover shaped to form a replacement nucleus pulposis for an intervertebral disc nucleus to the exterior of the structure and means for the reversible attachment of the valve body to an introducer, said introducer allowing injection of a hydrogel material, the improvement which provides that said introducer is adapted to accommodate an introducer rod and that the valve body is adapted to anchor the prosthetic device within a disc space.

2. A valve structure according to claim 1, further comprising obturating means operatively associated with said bore.

3. A valve structure according to claim 2, wherein the bore of the valve body is internally screw-threaded for interengagement with either of the obturating means or introducer rod.

4. A valve structure according to claim 1, wherein said body is generally symmetrical and said bore extends axially of said body.

5. A valve structure according to claim 1, wherein the introducer is engageable generally axially of the valve body by means of a readily reversible interlock.

6. A valve structure according to claim 1, wherein the introducer rod is screw threaded to engage the screw threaded longitudinal bore of the valve structure.

7. A valve structure according to claim 1, formed of an imaging transparent material.

8. A valve structure according to claim 1, wherein a strengthening member is incorporated into the cover and adapted to receive an end of the introducer rod.

9. A valve structure according to claim 1, further comprising a tubular screw driver and wherein the body is provided with engagement means to interlock with the tubular screwdriver, thereby in use to secure the obturating means without dislodgement of the in situ body.

10. A prosthetic cover shaped to form a replacement nucleus pulposis for an intervertebral disc, said cover comprising a permeable layer of an immunologically neutral material terminating in a valve structure to allow the introduction of a hydrogel material, characterized in that a transudative material is disposed on the intended inner faced of the cover to allow a through flow of low molecular weight materials having a molecular cut off below 12,000 daltons.

11. A prosthetic cover according to claim 10, wherein the cover terminates in a one-way valve structure to allow the introduction of the hydrogel material in a normally irreversible manner.

12. A prosthetic cover according to claim 10 wherein the low molecular weight material includes water.

13. A prosthetic cover according to claim 10, wherein the transudative material is formed in a layer which has a size below 9000 daltons.

14. A prosthetic cover according to claim 10, wherein the valve structure comprises an internal conical flap valve to permit the passage of an introducer.

15. A prosthetic cover according to claim 10, wherein a nose section is disposed on the cover in opposed relation to the valve structure and adapted to engage the distal end of the introducer rod during insertion.

16. A prosthetic cover according to claim 10, comprising a valve structure formed of an imaging transparent material.