Soft-tissue implants

Picha G, Drake R. Pillared-surface microstructure and soft-tissue implants effect of implant site and fixation. Journal of Biomedical Materials Research 1995, 30(3), 305-312. 

Devices such as soft tissue implants and methods for inhibiting fibrosis comprising non-gaseous CO, e.g. adsorbed in a zeolite, with anti-fibrotic activity [246]... 

The foreign body reaction occurring around soft tissue implants and thrombosis on surfaces in contact with blood are the major reactions encountered with implants. Both reactions involve the interaction of cells with the implant, especially in the later stages, and much previous study has therefore emphasized cellular events in the biocompatibility process. However, cells encounter foreign polymer implants under conditions that ensure the prior adsorption of a layer of protein to the polymer interface. The properties of the adsorbed layer are therefore important in mediating cellular response to the material. 

Foreign body reaction to soft tissue implants —Other processes such as contact lens fouling... 

The most common types of soft-tissue implants are (1) sutures and allied augmentation devices (2) percutaneous and cutaneous systems (3) maxillofacial devices (4) ear and eye prostheses (5) space-filling articles and (6) fluid transfer devices. 

Immediately after soft tissue implantation, a histological examination of the implant site shows a cellular response typical of acute trauma (hematoma), followed by the formation of a fibrous capsule around the implant (Chawla et ai, 1985). In osseous tissues, new bone formation begins to form periosteally and endosteally. Granulation tissue can be observed between the bone and the implant. A few giant cells are present, but no other inflammatory cells are observ ed (M ola et ai, 1991 Matsusue etal., 1991). 

Initially the implants were intended mainly to replace affected (i.e., broken bones, heart, vein, liver, pancrease) or malfunctioning body p>arts which people cannot live without. Subsequently, the industry of implants developed fast and now there are implants which are used for reconstructing and aesthetic purposes such as breast implants, bone facial implants and skin implants. According to the type of replaced tissue, they are divided into hard and soft implants. Hard tissue implants are usually made of metals or ceramics (bone implants, dental sealant, and joints) while soft tissue implants are made of polymers (blood vessels, skin, plastic surgery). 

Finally, polymers are resilient and easy to fabricate. They are used in sutures, blood vessels, hip sockets, ear, nose and other soft tissues implants [7]. 

A major use of plastics in surgery is to replace soft tissue such as a prosthetic breast, testicles, etc. The major polymer used here is poly(dimethylsiloxane) and these uses have been summarized in some recent articles (46,47). The major requirements for soft tissue replacements are (a) a consistency similar to the natural tissue being replaced, (b) no change in this consistency on aging in the body, (c) no fibrous ingrowth and (d) no adverse reactions with the body tissues. Porous and/or woven materials are usually unsuitable for this use since fibrous ingrowth normally leads to a pronounced loss in flexibility and a hard feel to the implant. Soft tissue implants usually do not come into direct contact with the blood and this problem is not particularly critical in this use. In... 

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