Prosthetic articles and methods for producing same

• US 5,487,933 A
• Filed: 09/19/1994
• Issued: 01/30/1996
• Est. Priority Date: 01/30/1991
• Status: Expired due to Fees

• Current Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Interpore International Inc. (Interpore Spine Limited)
• Inventors: White, Eugene W.
• Primary Examiner(s): Watkins, III, William P.
• Application Number:
  US08/308,762
• Time in Patent Office: 498 Days
• Field of Search: 428/131, 428/134, 428/156, 428/220, 428/213, 428/338, 623/11, 623/16, 264/220, 264/227, 264/310
• US Class Current: 428/131
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61F 2/105 Skin implants, e.g. artificial skin
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30263 cubical
• CPC Class Codes: A61F 2002/30298 Parallelepipedal body made by spirally rolling up a sheet or a strip around itself
• CPC Class Codes: A61F 2002/30303 polypod-shaped
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30599 stackable
• CPC Class Codes: A61F 2002/30785 parallel
• CPC Class Codes: A61F 2002/308 oblong
• CPC Class Codes: A61F 2002/30808 parallel
• CPC Class Codes: A61F 2002/30838 Microstructures
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/30896 perpendicular with respect to each other
• CPC Class Codes: A61F 2002/3092 : having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30929 : having at least two superposed coatings
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30968 : Sintering
• CPC Class Codes: A61F 2002/30978 : using electrical discharge machining [EDM]
• CPC Class Codes: A61F 2220/005 : using adhesives
• CPC Class Codes: A61F 2230/0019 : rectangular
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2230/0084 : cubical
• CPC Class Codes: A61F 2230/0091 : helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section
• CPC Class Codes: A61F 2250/0063 : Nested prosthetic parts
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00365 : Proteins; Polypeptides; Degradation products thereof
• CPC Class Codes: A61F 2310/00383 : Gelatin
• CPC Class Codes: A61L 27/56 : Porous materials, e.g. foams or sponges
• CPC Class Codes: B29C 39/148 : characterised by the shape of the surface
• CPC Class Codes: B29D 28/00 : Producing nets or the like, e.g. meshes, latticesby knotting D04G
• CPC Class Codes: B29L 2031/737 : Articles provided with holes, e.g. grids, sieves nets B29L2028/00
• CPC Class Codes: D04H 1/70 : characterised by the method of forming fleeces or layers, e.g. reorientation of fibres
• CPC Class Codes: Y10T 428/24273 : including aperture
• CPC Class Codes: Y10T 428/24298 : Noncircular aperture [e.g., slit, diamond, rectangular, etc.]
• CPC Class Codes: Y10T 428/24322 : Composite web or sheet
• CPC Class Codes: Y10T 428/24479 : including variation in thickness
• CPC Class Codes: Y10T 428/24562 : Interlaminar spaces
• CPC Class Codes: Y10T 428/24661 : Forming, or cooperating to form cells
• CPC Class Codes: Y10T 428/2495 : Thickness [relative or absolute]
• CPC Class Codes: Y10T 428/249953 : Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249975 : Void shape specified [e.g., crushed, flat, round, etc.]
• CPC Class Codes: Y10T 428/249978 : Voids specified as micro
• CPC Class Codes: Y10T 428/249991 : Synthetic resin or natural rubbers
• CPC Class Codes: Y10T 428/268 : Monolayer with structurally defined element

Abstract

A porous mesh structure is prepared in sheet form having a unique arrangement of main and secondary troughs on a first surface, and openings extending therethrough. The arrangement of troughs and openings creates an elaborate matrix of pores when the sheet is layer on itself in a front to back manner. This arrangement of pores and support structure emulates certain cortical bone structures and is therefore very effective as an artificial bone material. In addition, the porous structure has significant other potential uses outside the medical field and can be effectively applied accordingly, based on its fundamental structural attributes.

Claims

1. A non-woven porous mesh in sheet form, said mesh comprising:

a continuous sheet having a substantially uniform thickness between opposing sides;

a series of substantially parallel and linked main troughs extending in one horizontal direction along a first side of said sheet, said main troughs having a depth in said sheet that extends substantially into said sheet, said main troughs are spaced from adjacent main troughs by a distance approximately 1/2 a width of said main trough, said main troughs further linked to co-linear troughs by a first series of secondary shallow troughs;

one or more small openings extending through the bottom of each main trough to a second side of said sheet, said openings having a diameter that is approximately 1/3 the width of said main trough; and

a second series of secondary shallow troughs extending substantially perpendicular to and connecting said main troughs.

5. The porous mesh of claim 1 wherein said small openings have a diameter that is approximately equal to the width of said secondary troughs.

6. The porous mesh of claim 5 wherein said first series of secondary troughs extend substantially in parallel through said sheet.

7. The porous mesh of claim 6 wherein said second series of secondary troughs extend substantially parallel through said sheet.

8. A porous three dimensional body formed by wrapping the porous mesh of claim 1 around a mandrel having a select shape characteristic, wherein said porous mesh is wrapped in multiple layers to form a network of three dimensional pores extending throughout said body, and said mesh is layered front-to-back.

9. The porous body of claim 8 wherein said shape characteristic is cylindrical.

10. The porous body of claim 8 wherein said layers of mesh are adhesive bonded to adjacent layers.

11. A method of forming a porous sheet of claim 1 comprising the steps of:

making a primary form corresponding in shape to the final mesh structure;

casting a negative form by placing a curable material in fluid state into said primary form, allowing said material to cure and removing said cured negative form from said primary form;

casting said porous mesh by placing a mesh material in said negative form and allowing said mesh material to partial cure;

before said mesh material is completely cured, remove said mesh material from said negative form and wrap it around a shape defining mandrel; and

complete mesh curing while on said shape defining mandrel to form a shaped body having a three dimensional pore structure.

12. The method of claim 11 wherein said primary form is made by machining a metal sheet.

13. The method of claim 12 wherein said metal sheet is brass.

14. The method of claim 12 wherein said curable material is silicone rubber.

15. The method of claim 11 wherein said curable mesh material is hydroxyapatite (HA) and gelatin.

16. The method of claim 15 further comprising the step of chilling the HA prior to wrapping the mesh around said mandrel.

17. The method of claim 16 further comprising the step of drying the shaped body after removing it from the mandrel.

2. The porous mesh of claim 2 wherein said sheet thickness ranges between 200 to 2000 microns.

3. The porous mesh of claim 2 wherein the depth of said secondary troughs are approximately 1/2 the depth of said main troughs.

4. The porous mesh of claim 2 wherein said main troughs extend approximately 80 percent through said sheet thickness.