Bone Cement And Methods Of Use Thereof

• US 20070032567A1
• Filed: 07/31/2006
• Published: 02/08/2007
• Est. Priority Date: 06/17/2003
• Status: Abandoned Application

• Current Assignee: Depuy Synthes Products Incorporated (Johnson & Johnson)
• Original Assignee: Disc-O-Tech Medical Technologies Limited (Medtronic Plc)
• Inventors: Beyar, Mordechay, Globerman, Oren
• Application Number:
  US11/461,072
• Publication Number:
  US 20070032567A1
• Time in Patent Office: Days
• US Class Current: 523/116
• CPC Class Codes: A61L 24/043 Mixtures of macromolecular materials
• CPC Class Codes: A61L 2430/02 for reconstruction of bones; weight-bearing implants
• CPC Class Codes: C08L 25/04 Homopolymers or copolymers of styrene
• CPC Class Codes: C08L 33/12 Homopolymers or copolymers of methyl methacrylate

Abstract

A bone cement comprising an acrylic polymer mixture. The cement is characterized in that it achieves a viscosity of at least 500 Pascal-second within 180 seconds following initiation of mixing of a monomer component and a polymer component and characterized by sufficient biocompatibility to permit in-vivo use.

Claims

1. A bone cement comprising an acrylic polymer mixture, the cement characterized in that it achieves a viscosity of at least 500 Pascal-second within 180 seconds following initiation of mixing of a monomer component and a polymer component and characterized by sufficient biocompatibility to permit in-vivo use.

2. A bone cement according to claim 1, wherein the viscosity of the mixture remains between 500 and 2000 Pascal-second for a working window of at least 5 minutes after the initial period.

3. A bone cement according to claim 2, wherein the working window is at least 8 minutes long.

4. A bone cement according to claim 1, wherein the mixture includes PMMA.

5. A bone cement according to claim 1, wherein the mixture includes Barium Sulfate.

6. A bone cement according to claim 4, wherein the PMMA is provided as a PMMA/styrene copolymer.

7. A bone cement according to claim 4, wherein the PMMA is provided as a population of beads divided into at least two sub-populations, each sub-population characterized by an average molecular weight.

8. A bone cement according to claim 7, wherein a largest sub-population of PMMA beads is characterized by an MW of 150,000 Dalton to 300,000 Dalton.

9. A bone cement according to claim 7, wherein a largest sub-population of PMMA beads includes 90-98% (w/w) of the beads.

10. A bone cement according to claim 7, wherein a high molecular weight sub-population of PMMA beads is characterized by an average MW of at least 3,000,000 Dalton.

11. A bone cement according to claim 7, wherein a high molecular weight sub-population of PMMA beads includes 2 to 3% (w/w) of the beads.

12. A bone cement according to claim 7, wherein a low molecular weight sub-population of PMMA beads is characterized by an average MW of less than 15,000 Dalton.

13. A bone cement according to claim 7, wherein a low molecular weight sub-population of PMMA beads includes 0.75 to 1.5% (W/W) of the beads.

14. A bone cement according to claim 4, wherein the PMMA is provided as a population of beads divided into at least two sub-populations, each sub-population characterized by an average bead diameter.

15. A bone cement according to claim 14, wherein at least one bead sub-population of characterized by an average diameter is further divided into at least two sub-sub-populations, each sub-sub-population characterized by an average molecular weight.

16. A bone cement according to claim 14, wherein the PMMA is provided as a population of beads divided into at least three sub-populations, each sub-population characterized by an average bead diameter.

17. A bone cement according to claim 1, further comprising processed bone and/or synthetic bone.

18. A bone cement according to claim 1, characterized in that the cement achieves a viscosity of at least 500 Pascal-second when 100% of a polymer component is wetted by a monomer component.

19. A bone cement according to claim 1, wherein the viscosity is at least 800 Pascal-second.

20. A bone cement according to claim 1, wherein the viscosity is at least 1500 Pascal-second.

21. A bone cement according to claim 1, wherein the viscosity is achieved within 2 minutes.

22. A bone cement according to claim 1, wherein the viscosity is achieved within 1 minute.

23. A bone cement according to claim 1, wherein the viscosity is achieved within 45 seconds.

24. A bone cement comprising:

a polymer component; and

a monomer component;

wherein contacting the polymer component and the monomer component produces a mixture which attains a viscosity greater than 200 Pascal-second within 1 minute from onset of mixing and remains below 2000 Pascal-second until at least 6 minutes from onset of mixing.

25. A bone cement according to claim 24, wherein the polymer component comprises an acrylic polymer.

26. A particulate mixture formulated for preparation of a bone cement, the mixture comprising:

(a) 60 to 80% polymer beads comprising a main sub-population characterized by an MW of 150,000 Dalton to 300,000 Dalton and a high molecular weight sub-population characterized by an MW of 3,000,000 Dalton to 4,000,000 Dalton; and

(b) 20 to 40% of a material which is non-transparent with respect to X-ray.

27. A mixture according to claim 26, wherein the polymer beads comprise a third subpopulation characterized by an MW of 10,000 Dalton to 15,000 Dalton.

28. A method of making a polymeric bone cement, the method comprising:

(a) defining a viscosity profile including a rapid transition to a working window characterized by a high viscosity;

(b) selecting a polymer component and a monomer component to produce a cement conforming to the viscosity profile; and

(c) mixing the polymer component and a monomer component to produce a cement which conforms to the viscosity profile.