Implants with a cover which resists formation of firm spherical encapsulation

• US 5,141,581 A
• Filed: 08/08/1991
• Issued: 08/25/1992
• Est. Priority Date: 10/08/1972
• Status: Expired due to Fees

• Current Assignee: Bristol-Myers Squibb Company
• Original Assignee: Bristol-Myers Squibb Company
• Inventors: Markham, Harold A.
• Primary Examiner(s): Weston, Caleb
• Application Number:
  US07/391,731
• Time in Patent Office: 383 Days
• Field of Search: 156/242, 156/245, 264/46.4, 264/259, 264/260, 623/7, 623/8, 623/11
• US Class Current: 156/242
• CPC Class Codes: A61F 2/12 Mammary prostheses and implants
• CPC Class Codes: B29C 44/5618 Impregnating foam articles
• CPC Class Codes: B29L 2031/7532 Artificial members, protheses
• CPC Class Codes: Y10S 623/901 Method of manufacturing prosthetic device

Abstract

A transition layer for an implant to be placed in the human body. The implant has a core, and the transition surface surrounds the core. The transition layer is an open celled foam with cut surfaces. An adhesive adheres one surface to the core, and penetrates the transition layer a limited distance so as to leave over the entire surface, microstructures of cell fragments providing for tissue attachment without formation of a firm encapsulation.

Claims

1. A method of forming a surgical implant which resets the formation of firm spherical encapsulation comprising steps of:

providing a silicone substrate implant,

providing first and second sheets of open-cell foam;

physically bonding said first and second sheets, with an adhesive layer, to adjacent portions of the outer surface of said silicone substrate implant, and

thereafter, heat sealing adjacent edges of said first and second sheets together,

said bonding including said adhesive layer penetrating into said first and second sheets so that uncoated and unclouded cells and fibers remain at the outer surfaces of said sheets to a depth sufficient for surrounding tissue to become structurally congruent over the surface which is contiguous to tissue and to a depth insufficient to permit invasive in growth which would result in the formation of a grossly palpable, rigid, and fibrous encapsulation of the implant.

2. The method of claim 1 including,

said heat sealing including thereby forming a continuous, thin, flexible feathered edge at the junction of said fist and second sheets.

3. The method of claim 1 including,

said first and second sheets covering the entire outer surface of said implant with a single sheet layer.

4. The method of claim 1 including,

before said bonding, laser cutting said fist and second sheets from a block of foam.

5. The method of claim 1 including,

said foam being polyurethane foam and said adhesive layer comprising silicone adhesive.

6. The method of claim 1 including,

said heat sealing including applying a heat sealing iron to the edges of said first and second sheets.

7. The method of claim 1 including,

said bonding including applying said first sheet to one portion of said implant and said second sheet to an opposite portion of said implant so that the juncture of said first and second sheets encircles said implant and said implant thereby is covered by a single sheet layer.

8. The method of claim 1 including,

before said bonding, cuting said first sheet so as to open some of the cells on its inner and outer surfaces, and at least on said outer surface thereby forming a substantial number of cellwall fragments to form fibers for tissue contiguity.

9. The method of claim 1 including,

before said bonding, forming said implant of a gel-sealant combination.

10. The method of claim 1 including,

said implant having a the generally flat portion, a rounded portion and a radius where said flat portion stops and said rounded portion starts, and said heat sealing being generally at said radius.

11. The method of claim 1 including,

forming said sheets of a single chain, co-polymer polyurethane.

12. The method of claim 11 including,

forming said implant of a gelled medical grade dimethyl polysiloxane.

13. The method of claim 1 including,

said bonding step including applying the adhesive layer to said outer surface f said silicone substrate implant and then laying said first sheet on said adhesive layer while the adhesive is still liquid.

14. The method of claim 13 including,

said applying including brush coating said adhesive layer to said outer surface.

15. The method of claim 13 including,

said applying including knife coasting said adhesive layer to said outer surface.

16. The method of claim 13 including,

after said laying, smoothing said fist sheet on said adhesive layer.

17. The method of claim 1 including,

before said bonding, forming said silicone substrate implant in a mold comprising first and second mold parts.

18. The method of claim 17 including,

at least a portion of said bonding step being done with said silicone substrate implant positioned in said first mold part.

19. A method of forming a surgical implant which resists the formation of firm spherical encapsulation comprising the steps of:

providing a self-shape retaining substrate implant,

providing first and second sheets of open-cell foam;

physically bonding said first and second sheets, with an adhesive layer, to adjacent portions of the outer surface of said substrate implant, and

thereafter, heat sealing adjacent edges f said first and second sheets together,

said bonding including said adhesive layer not penetrating only pat-way into said first and second sheets so that uncoated and unclouded cells and fibers remain at the other surfaces of said sheets to a depth sufficient for surrounding tissue to become structurally congruent over the surface which is continuous to tissue and to a depth to inhibit the formation of a grossly palpable, rigid, and fibrous encapsulation of the implant.