Methods, materials and apparatus for treating bone and other tissue

• US 8,809,418 B2
• Filed: 03/11/2013
• Issued: 08/19/2014
• Est. Priority Date: 03/21/2004
• Status: Active Grant

• Current Assignee: DePuy Synthes Products LLC (Johnson & Johnson)
• Original Assignee: DePuy Synthes Products LLC (Johnson & Johnson)
• Inventors: Beyar, Mordechay, Globerman, Oren, Shavit, Ronen, Wachsler-Avrahami, Hila
• Primary Examiner(s): ZISKA, SUZANNE E
• Application Number:
  US13/793,385
• Publication Number:
  US 20130261217A1
• Time in Patent Office: 526 Days
• Field of Search: None
• US Class Current: 523/116
• CPC Class Codes: A61B 17/1604 Chisels; Rongeurs; Punches; Stamps
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/3421 Cannulas
• CPC Class Codes: A61B 17/8811 characterised by the introducer tip, i.e. the part inserted into or onto the bone
• CPC Class Codes: A61B 17/8816 characterised by the conduit, e.g. tube, along which fluid flows into the body or by conduit connections
• CPC Class Codes: A61B 17/8822 characterised by means facilitating expulsion of fluid from the introducer, e.g. a screw pump plunger, hydraulic force transmissions, application of vibrations or a vacuum
• CPC Class Codes: A61B 17/8836 for heating, cooling or curing of bone cement or fluid fillers
• CPC Class Codes: A61B 2017/00539 hydraulically
• CPC Class Codes: A61B 2017/2905 flexible
• CPC Class Codes: A61B 2090/3937 Visible markers
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2/4601 for introducing bone substitute, for implanting bone graft implants or for compacting them in the bone cavity
• CPC Class Codes: A61F 2002/4693 hydraulic
• CPC Class Codes: A61L 24/043 Mixtures of macromolecular materials
• CPC Class Codes: A61L 24/06 obtained by reactions only involving carbon-to-carbon unsaturated bonds A61L24/043, A61L24/046 take precedence
• CPC Class Codes: A61L 2430/02 for reconstruction of bones; weight-bearing implants
• CPC Class Codes: A61L 2430/38 for reconstruction of the spine, vertebrae or intervertebral discs
• CPC Class Codes: A61L 27/26 Mixtures of macromolecular compounds
• CPC Class Codes: B01F 27/95 with stirrers having planetary motion, i.e. rotating about their own axis and about a sun axis
• CPC Class Codes: B01F 35/3202 Hand driven
• CPC Class Codes: B01F 35/53 : characterised by the configuration of the interior, e.g. baffles for facilitating the mixing of components
• CPC Class Codes: B01F 35/75425 : using pistons or plungers
• CPC Class Codes: B01F 35/754251 : reciprocating in the mixing receptacle
• CPC Class Codes: C08L 33/12 : Homopolymers or copolymers of methyl methacrylate

Abstract

A bone cement comprising a first component and a second component, wherein contacting the first component and the second component produces a mixture which attains a high viscosity an initial period and the viscosity of the mixture remains relatively stable for a working time of at least 5 minutes after the initial setting period, and the mixture is suitable for in-vivo use.

Claims

1. A bone cement comprising;

a first powder component containing polymer beads having a first average molecular weight and further containing a high molecular weight population of beads having a second average molecular weight that is higher than the first average molecular weight; and

a second liquid component containing monomers,

wherein, the first average molecular weight, the second average molecular weight, and the percentage of beads having the second average molecular weight are selected so that contacting the first component and the second component produces a mixture having a viscosity profile with three phases defining an initial period a working period, and a hardening period,

wherein, during the initial period, the viscosity increases at a rate of change that decreases over time until the mixture attains a viscosity greater than 500 Pascal seconds within 180 seconds from mixing the first and second components,

wherein, during, the working period of at least 5 minutes, the viscosity remains between 500 and 2000 Pascal seconds

wherein, during the hardening period, the viscosity increases at a rate of change that increases over time until the mixture hardens, and

wherein the mixture is suitable for in-vivo use.

2. The bone cement of claim 1, wherein the working period is at least 8 minutes long.

3. The bone cement of claim 1, wherein the initial period is less than 3 minutes.

4. The bone cement of claim 1, wherein the initial period does not exceed 1 minute.

5. The hone cement of claim 1, wherein the first component includes PMMA and Barium Sulfate.

6. The bone cement of claim 1, wherein the second component includes MMA and DMPT.

7. The bone cement of claim 1, wherein the first component includes PMMA, Barium Sulfate, and Benzoyl Peroxide, and wherein the second component includes MMA, DMPT, and Hydroquinone.

8. The bone cement of claim 1, wherein the viscosity of greater than 500 Pascal-second results at least partly from a polymerization reaction.

15. The bone cement of claim 1, wherein during the initial period, the mixture has substantially no liquid phase.

16. The bone cement of claim 1, wherein during the initial period, the mixture achieves a viscosity of greater than 900 Pascal seconds.

17. The bone cement of claim 1, wherein the polymer beads comprise acrylic polymer beads.

18. The bone cement of claim 1, wherein viscosity of t he mixture changes by less than 20% over a period of 5 minutes during the working period.

9. A bone cement comprising:

a first powder component containing polymer beads having a first average molecular weight and further containing a high molecular weight population of beads having a second average molecular weight that is higher than the first average molecular weight; and

a second liquid component containing monomers,

wherein, the first average molecular weight, the second average molecular weight, and the percentage of beads having the second average molecular weight are selected so that contacting the first component and the second component produces a mixture having a viscosity profile with three phases defining an initial period, a working period, and a hardening period,

wherein, during the initial period, the viscosity increases at a rate of change that decreases over time until the mixture attains a viscosity greater than 200 Pascal seconds within 1 minute from mixing the first and second components,

wherein, during the working period of at least 5 minutes, the viscosity of the mixture remains between 200 and 2000 Pascal seconds, wherein the viscosity of said mixture is changing by less than 10% in a period of 2 minutes within said working period

wherein, during the hardening period, the viscosity increases at a rate of change that increases over time until the mixture hardens, and

wherein the mixture is suitable for in-vivo use.

10. The bone cement of claim 9, wherein the the first component contains PMMA beads and the second component contains MMA monomers, the high molecular weight population of PMMA beads having an average molecular weight between about 600,000 Dalton and about 1,200,000 Dalton.

11. The bone cement of claim 10, wherein the first component contains about 69.4% w/w PMMA, about 30.1% Barium Sulfate, and about 0.5% Benzoyl Peroxide;

and wherein the second component contains about 98.5% v/v MMA, about 1.5% DMPT, and about 20 ppm Hydroquinone.

12. The bone cement of claim 10, wherein the first average molecular weight of the PMMA heads is between about 80,000 Dalton and about 180,000 Dalton.

13. The bone cement of claim 10, wherein the first average molecular weight of the PMMA beads is about 110,000 Dalton.

14. The bone cement of claim 10, wherein at least 80% of the PMMA beads have a size between 10 and 200 microns.

19. The bone cement of claim 9, wherein the working period is at least 8 minutes long.