Implants and methdos for manufacturing same

Abstract

Implantable prosthesis, components of prosthesis, and methods of making same are provided. The methods generally include the steps of providing an implant shell, applying a curable fluid composition to the shell to form a coating thereon and applying a particulate component to the composition. The composition is a mixture, for example, an emulsion, containing a silicone-based elastomer dispersion and droplets of a suspended leachable agent. After the elastomer is stabilized and cured, the particulate component and leachable agent are removed, resulting in an implantable member having a porous, open-cell surface texture designed to be effective in reducing incidence of capsular formation or contraction.

Description

[0001]This application claims priority to U.S. Provisional Patent Application No. 61 / 252,330, filed on Oct. 16, 2009, the entire disclosure of which is incorporated herein by this specific reference.BACKGROUND[0002]The present invention generally relates to soft tissue implants and more specifically relates to soft tissue implants designed to enhance fixation in the body and / or alter or reduce capsular formation.[0003]Soft tissue implants, particularly mammary prostheses, are plagued by problems of capsular formation and contracture. Soon after an implant is placed into the body, an inflammatory response begins to deposit a fibrous capsule around the implant. In most cases, particularly for relatively large and smooth implants, the capsule is comprised of highly organized or aligned collagen fibers. As the capsule matures, certain events may trigger the differentiation of fibroblasts to a contractile phenotype (myofibroblasts). In this or similar scenarios, and if the collagen fiber...

AI Technical Summary

Benefits of technology

[0007]The present invention provides implantable members and methods for manufacturing implantable members, for example, prostheses, for example, mammary prostheses, as well as components of prostheses, for example, elastomeric shells, which serve as components of mammary prostheses. The invention further provides coverings, for example, laminates for applying to surfaces of implantable devices. The implantable members have surfaces which may enhance fixation and / or alter or reduce capsular formation. In one aspect of the invention, the textured surfaces are defined by a network of interconnected pores and channels which encourages tissue ingrowth and discourages organization of the collagen capsule. Generally, the pores have, on average, more than two interconnections assuming that the average number of interconnections per pore does not vary significantly.

[0012]In one embodiment, the particulate coating itself is used to stabilize the coating composition, for example, by absorbing some or all of the solvent, increasing the rate of polymerization of crosslinking of the silicone, promoting precipitation of the silicone or porogen, or a combination of one or more of the above.

[0013]Once solidified, the leachable agent contained in the composition and the particles embedded therein are then removed from the coating thereby revealing a network of interconnected pores (the structure may include both relatively large pores and relatively smaller pores, for example, micropores) within the cured elastomer. The surface topography created by the processes described herein, when used as a part of an implant at the tissue / implant interface, may be highly effective in altering capsular formation so as to achieve a more preferred morphology, or in reducing or preventing capsular contracture, relative to conventional surface topographies.

[0016]Generally, the particles, which are typically larger in size than the dispersed leachable agent, serve to create cavities or pores in the cured elastomer while the dispersed leachable agent serves to create microcavities or micropores which serve as interconnections between the pores. This network of interconnected pores and micropores facilitates tissue ingrowth, encourages better fixation of the implant in the patient, and discourages organization of the fibrous capsule, which may help reduce or prevent capsule formation and contraction.

Problems solved by technology

Soft tissue implants, particularly mammary prostheses, are plagued by problems of capsular formation and contracture.

Capsular contracture can be debilitating to the patient because of discomfort or even pain caused thereby, can diminish the efficacy of the aesthetic results in both the look and feel of the implant, and can sometimes damage the implant itself.

Problems with capsular formation and contracture occur in many implant types such as pacemakers, dura matter substitutes, implantable cardiac defibrillators, pacemaker leads, hernia repair meshes as well as breast and other esthetic implants.

However, polyurethane foam coatings are biodegradable and lose their efficacy once the polyurethane degrades.

Further, it can be appreciated that degradation of polyurethane foam into the body is undesirable and potentially unhealthy.

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