Polymer re-inforced anatomically accurate bioactive protheses

• US 6,605,293 B1
• Filed: 05/18/2000
• Issued: 08/12/2003
• Est. Priority Date: 05/20/1999
• Status: Expired due to Fees

• Current Assignee: Trustees of Boston University
• Original Assignee: Trustees of Boston University
• Inventors: Wu, Benjamin M., Giordano, Russell A.
• Primary Examiner(s): Spear, James M.
• Assistant Examiner(s): Bennett, Rachel M.
• Application Number:
  US09/574,146
• Time in Patent Office: 1,181 Days
• Field of Search: 424/423, 424/422, 424/484
• US Class Current: 424/423
• CPC Class Codes: A61F 2/2803 for mandibular reconstruction temporo-mandibular joints A61F2/3099; bone plates for the jaw A61B17/8071
• CPC Class Codes: A61F 2/2875 Skull or cranium A61F2/2803 and A61F2/3099 take precedence
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2250/0023 differing in porosity
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00155 Gold or Au-based alloys
• CPC Class Codes: A61F 2310/00203 containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00239 containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00329 Glasses, e.g. bioglass
• CPC Class Codes: A61L 27/42 having an inorganic matrix
• CPC Class Codes: A61L 27/425 of phosphorus containing material, e.g. apatite
• CPC Class Codes: A61L 27/46 : with phosphorus-containing inorganic fillers
• CPC Class Codes: B33Y 80/00 : Products made by additive manufacturing

Abstract

Customized implants for use in reconstructive bone surgeries where anatomical accuracy and bone adaptation are important, such as plastic and craniomaxillofacial reconstructions. This implant comprises a porous surface layer and a tough inner core of interpenetrating phase composite. The porous surface layer enhances the biocompatibility, tissue ingrowth, and implant stability. The tough inner core improves the mechanical properties of the implant with a high fracture toughness and a low modulus. The anatomical accuracy of the implants will minimize the intra-operative manipulation required to maintain a stable host bone-implant interface.

Claims

1. A method for forming an implant having an inner core and an outer layer which comprises:

fabricating a preform with an open pore network;

coating at least a portion of the outer layer of the preform with a fugitive material to form an inhibition layer and to define infusion channels;

infusing selected regions of the inner core through the infusion channels with at least one infusing media;

forming an interpenetrating phase composite in the inner core; and

removing the fugitive material from the outer layer thereby forming a porous outer layer.

2. The method of claim 1 wherein the preform is fabricated by sintering.

3. The method of claim 2 wherein the preform comprises a material selected from the group consisting of hydroxyapatite, bioactive glass, calcium phosphates, xenografts, allografts, autografts, isografts, ultrahigh density zirconia, zirconia toughened alumina, alumina, sapphire, titanium and gold/palladium alloys.

4. The method of claim 1 wherein the fugitive material is selected from the group consisting essentially of polyethylene glycol, waxes, hydrogels, or acrylic latexes.

5. The method of claim 1 wherein the infusion media is selected from the group consisting of acrylates, thermoplastics, epoxies, resorbable polymers, and water soluble/hydrophilics.

6. The method of claim 5 which comprises:

infusing the inner core with at least two infusion media.

7. The method of claim 5 which comprises:

infusing the inner core with an inorganic material selected from the group consisting of resorbable glasses and silica.

8. The method of claim 5 which comprises:

infusing the inner core with a material selected from the group consisting of drug molecules, growth factors, adhesion peptides, promotors and activators.

9. The method of claim 5 which comprises:

infusing the inner core with inorganic precursors selected from the group consisting of alkoxides, metal alkoxides, silicon alkoxides, non-silicate tetravalent metal alkoxides and sol-gel organic-inorganic hybrids.

10. The method of claim 5 which comprises:

removing fugitive material.

27. The method of claim 5 wherein the acrylates are selected from the group consisting of TEGDMA (triethylene glycol dimethacrylate), MMA (methyl methacrylate), and Bis GMA (2,2-bis[4(2-hydroxy-3 methacryloyloxy-propyloxy)-phenyl] propane);

the thermophalstics are selected from the group consisting of styrene, vinyl acetate, vinyl choloride, polyethylene, PTFE (potytetraflouroethylene) and polypropylene;

the epoxies are selected from the group consisting of polytherketone, polyetheretherketone, and polyphenylene oxide;

the resorbable polymers are selected from the group consisting of polylactic acid, polyglycolic acid, polycaprolactone, polytrimethylene carbonate, polydioxanone, polyiminocarbonates, polyamides, polyorthoesters, polyanhydrides, polyhydroxyalkanoates, and polyhydroxybutyrate; and

the water soluble/hydrophilics are selected from the group consisting of polyvinyl alcohol, polyvinyl alcohol-based mixtures, collagen gel/poly alpha hydroxyacids, cellulose and waxes.

11. An implant which comprises:

a preform with an open pore network, the preform having an inner core and an outer layer, the inner core infused with at least two infusion media which form an interpenetrating phase composite in the inner core, the preform characterized by a flexural strength, a modulus and a fracture toughness which matches that of a target bone host, and at least a portion of the outer layer being porous.

12. The implant of claim 11 wherein the preform is comprised of a material selected from the group consisting of hydroxyapatite, bioactive glass, calcium phosphates, xenografts, allografts, autografts, isografts, ultrahigh density zirconia, zirconia toughened alumina, alumina, sapphire, titanium and gold/palladium alloys.

13. The implant of claim 11 further comprising a fugitive material selected from the group consisting essentially of polyethylene glycol, waxes, hydrogels or acrylic latexes.

14. The implant of claim 11 wherein the infusion media is selected from the group consisting of acrylates, thermoplastics, epoxies, resorbable polymers, and water soluble/hydrophilics.

15. The implant of claim 11 wherein the inner core is infused with at least two infusion media.

16. The implant of claim 14 wherein the inner core is infused with an inorganic material selected from the group consisting of resoluble glasses and silica.

17. The implant of claim 14 wherein the inner core is infused with a material selected from the group consisting of drug molecules, growth factors, adhesion peptides, promoters and activators.

18. The implant of claim 14 wherein the inner core is infused with inorganic precursors selected from the group consisting of alkoxides, metal alkoxides, silicon alkoxides, non-silicate tetravalent metal alkoxides and sol-gel organic-inorganic hybrids.

28. The implant of claim 11 wherein the acrylates are selected from the group consisting of TEGDMA (triethylene glycol dimethacrylate), MMA (methyl methacrylate), and Bis GMA (2,2-bis[4(2-hydroxy-3 methacryloyloxy-propyloxy)-phenyl] propane);

the thermophalstics are selected from the group consisting of styrene, vinyl acetate, vinyl choloride, polyethylene, PTFE (potytetraflouroethylene) and polypropylene;

the epoxies are selected from the group consisting of polytherketone, polyetheretherketone, and polyphenylene oxide;

the resorbable polymers are selected from the group consisting of polylactic acid, polyglycolic acid, polycaprolactone, polytrimethylene carbonate, polydioxanone, polyiminocarbonates, polyamides, polyorthoesters, polyanhydrides, polyhydroxyalkanoates, and polyhydroxybutyrate; and

the water soluble/hydrophilics are selected from the group consisting of polyvinyl alcohol, polyvinyl alcohol-based mixtures, collagen gel/poly alpha hydroxyacids, cellulose and waxes.

19. A method for forming an implant having an inner core and an outer layer which comprises:

fabricating a preform with an open pore network;

coating at least a portion of the outer layer of the preform with a fugitive material to form an inhibition layer and to define infusion channels;

infusing selected regions of the inner core through the infusion channels with at least two infusing media;

forming two interpenetrating phase composites in the inner core; and

removing the fugitive material from the outer layer thereby forming a porous outer layer.

20. The method of claim 19 wherein the preform is fabricated by sintering.

21. The method of claim 19 wherein the preform comprises a material selected from the group consisting of hydroxyapatite, bioactive glass, calcium phosphates, xenografts, allografts, autografts, isografts, ultrahigh density zirconia, zirconia toughened alumina, alumina, sapphire, titanium and gold/palladium alloys.

22. The method of claim 21 wherein the infusion media is selected from the group consisting of acrylates, thermoplastics, epoxies, resorbable polymers, and water soluble/hydrophilics.

23. The method of claim 19 wherein the fugitive material is selected from the group consisting essentially of polyethylene glycol, waxes, hydrogels or acrylic latexes.

24. The method of claim 23 which comprises:

infusing the inner core with an inorganic material selected from the group consisting of resorbable glasses and silica.

25. The method of claim 23 which comprises:

infusing the inner core with a material selected from the group consisting of drug molecules, growth factors, adhesion peptides, promotors and activators.

26. The method of claim 23 which comprises:

infusing the inner core with inorganic precursors selected from the group consisting of alkoxides, metal alkoxides, silicon alkoxides, non-silicate tetravalent metal alkoxides and sol-gel organic-inorganic hybrids.

29. The method of claim 21 wherein the acrylates are selected from the group consisting of TEGDMA (triethylene glycol dimethacrylate), MMA (methyl methacrylate), and Bis GMA (2,2-bis[4(2-hydroxy-3 methacryloyloxy-propyloxy)-phenyl] propane);

the thermophalstics are selected from the group consisting of styrene, vinyl acetate, vinyl choloride, polyethylene, PTFE (potytetraflouroethylene) and polypropylene;

the epoxies are selected from the group consisting of polytherketone, polyetheretherketone, and polyphenylene oxide;

the resorbable polymers are selected from the group consisting of polylactic acid, polyglycolic acid, polycaprolactone, polytrimethylene carbonate, polydioxanone, polyiminocarbonates, polyamides, polyorthoesters, polyanhydrides, polyhydroxyalkanoates, and polyhydroxybutyrate; and

the water soluble/hydrophilics are selected from the group consisting of polyvinyl alcohol, polyvinyl alcohol-based mixtures, collagen gel/poly alpha hydroxyacids, cellulose and waxes.