Hydrogel balloon prosthesis for nucleus pulposus

• US 20070073402A1
• Filed: 08/25/2006
• Published: 03/29/2007
• Est. Priority Date: 08/26/2005
• Status: Active Grant

• Current Assignee: Drexel University, Synthes USA LLC (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson)
• Inventors: Vresilovic, Edward, Clemow, Alastair, Lowman, Anthony, Keane, Michael, Marcolongo, Michele
• Granted Patent: US 8,287,595 B2
• Time in Patent Office: Days
• US Class Current: 623/17.120
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• CPC Class Codes: A61F 2002/444 for replacing the nucleus pulposus
• CPC Class Codes: A61L 27/52 Hydrogels or hydrocolloids

Abstract

A prosthesis for replacing or supplementing a nucleus pulposus of an intervertebral disk is an expandable container having flexible walls, the container being adapted to be inserted into a central cavity of an intervertebral disk through a narrow cannula, and the flexible walls are made from a biocompatible hydrogel. A preferred hydrogel is a cryogel formed from an aqueous solution of poly(vinyl alcohol) and poly(vinyl pyrrolidone). The prosthesis may be prepared by dip-coating a mandrel with an aqueous solution of a hydrogel-forming polymer or mixture of such polymers, gelling the coated solution by chilling, and subjecting the gelled coating to a series of repeated freeze-thaw treatments. In use, the prosthesis is inserted into a central cavity of an intervertebral disk and filled with biocompatible material, e.g., a biocompatible liquid, a biocompatible polymer, and a biocompatible hydrogel, particularly a thermogelling hydrogel.

Claims

1. A prosthesis for replacing or supplementing a nucleus pulposus of an intervertebral disk, comprising an expandable container having flexible walls, said container being adapted to be inserted into the central cavity of the intervertebral disk through a narrow cannula, wherein said flexible walls are made from a material comprising a biocompatible hydrogel.

2. The prosthesis of claim 1, wherein said biocompatible hydrogel is a cryogel formed from an aqueous solution comprising poly(vinyl alcohol).

3. The prosthesis of claim 1, wherein said biocompatible hydrogel is a cryogel formed from an aqueous solution comprising poly(vinyl alcohol) and poly(vinyl pyrrolidone).

4. The prosthesis of claim 1, having a shape when expanded generally conforming to the shape of a natural nucleus pulposus.

5. The prosthesis of claim 1, wherein said flexible walls have a thickness from 0.02 mm to 1.00 mm.

6. A prosthesis for replacing or supplementing a nucleus pulposus of an intervertebral disk, comprising an expandable container having flexible walls, said container being adapted to be inserted into the central cavity of the intervertebral disk through a narrow cannula, wherein said flexible walls are made from a material comprising a first biocompatible hydrogel, said expandable container being filled with a biocompatible material selected from the group consisting of a biocompatible liquid, a biocompatible polymer, and a second biocompatible hydrogel.

7. The prosthesis of claim 6, wherein said first biocompatible hydrogel is a cryogel formed from an aqueous solution comprising poly(vinyl alcohol).

8. The prosthesis of claim 6, wherein said first biocompatible hydrogel is a cryogel formed from an aqueous solution comprising poly(vinyl alcohol) and poly(vinyl pyrrolidone).

9. The prosthesis of claim 6, having a shape when expanded generally conforming to the shape of a natural nucleus pulposus.

10. The prosthesis of claim 6, wherein said second biocompatible hydrogel is a thermogelling hydrogel.

11. The prosthesis of claim 10, wherein said thermogelling hydrogel is prepared from a mixture of a first aqueous solution comprising poly(N-isopropylacrylamide) and a second aqueous solution comprising poly(vinyl alcohol).

12. The prosthesis of claim 10, wherein said thermogelling hydrogel is prepared from a mixture of a first aqueous solution comprising poly(N-isopropylacrylamide) and a second aqueous solution comprising poly(ethylene glycol).

13. The prosthesis of claim 10, wherein said thermogelling hydrogel is prepared from an aqueous solution comprising a poly(N-isopropylacrylamide)-grafted poly(ethylene glycol) polymer.

14. The prosthesis of claim 10, wherein said thermogelling hydrogel is prepared from an aqueous solution comprising a poly(ethylene glycol)-poly(N-isopropylacrylamide)-poly(ethylene glycol) triblock polymer.

15. The prosthesis of claim 6, wherein said flexible walls have a thickness from 0.02 mm to 1.00 mm.

16. A method of forming a container from a hydrogel, comprising the steps of:

(i) dip-coating a mandrel with an aqueous solution of a hydrogel-forming polymer or a mixture of said hydrogel-forming polymer to form a coated solution,

(ii) preparing the coated solution to form a gelled coating, and

(iii) subjecting the coating to a series of freeze-thaw treatments.

17. The method of claim 16, wherein said preparing step is chilling.

18. The method of claim 16, wherein said freeze-thaw treatments are repeated.

19. The method of claim 16, wherein said hydrogel-forming polymer is poly(vinyl alcohol).

20. The method of claim 16, wherein said mixture of hydrogel-forming polymer is a mixture of poly(vinyl alcohol) and poly(vinyl pyrrolidone).

21. A method of replacing or supplementing a nucleus pulposus of an intervertebral disk, comprising the steps of:

(i) inserting a flexible-walled container made from a first biocompatible hydrogel into the nucleus pulposus by a minimally invasive surgical procedure, and

(ii) subsequently introducing into said flexible-walled container a biocompatible material for replacing or supplementing the nucleus pulposus.

22. The method of claim 21, wherein said biocompatible hydrogel is a cryogel formed from an aqueous solution comprising poly(vinyl alcohol).

23. The method of claim 21, wherein said biocompatible hydrogel is a cryogel formed from an aqueous solution comprising poly(vinyl alcohol) and poly(vinyl pyrrolidone).

24. The method of claim 21, wherein said flexible-walled container has a shape when inflated generally conforming to the shape of a natural nucleus pulposus.

25. The method of claim 21, wherein said biocompatible material is selected from the group consisting of a biocompatible liquid, a biocompatible polymer, and a second biocompatible hydrogel.

26. The method of claim 25, wherein said second biocompatible hydrogel is a thermogelling hydrogel.

27. The method of claim 26, wherein said thermogelling hydrogel is prepared from a mixture of a first aqueous solution comprising poly(N-isopropylacrylamide) and a second aqueous solution comprising poly(vinyl alcohol).

28. The method of claim 26, wherein said thermogelling hydrogel is prepared from a mixture of a first aqueous solution comprising poly(N-isopropylacrylamide) and a second aqueous solution comprising poly(ethylene glycol).

29. The method of claim 26, wherein said thermogelling hydrogel is prepared from an aqueous solution comprising a poly(N-isopropylacrylamide)-grafted poly(ethylene glycol) polymer.

30. The method of claim 26, wherein said thermogelling hydrogel is prepared from an aqueous solution comprising a poly(ethylene glycol)-poly(N-isopropylacrylamide)-poly(ethylene glycol) triblock polymer.