Soft tissue response to silicones

Although the term silicone refers to a group of organic silicone compounds, the one most commonly used in medicine is composed of a polymer known as dimethypolysiloxane (DMPS). In silicone gel the polymer is cross-linked the more cross-linking, the more solid is the gel. Liquid silicone consists of glucose-linked DMPS polymer chains. Silicones first became commercially available in 1943, with the first subdermal implantation of silicone occurring in the late 1940s [1-3]. Silicones have since been developed for a wide variety of medical applications, most notably in joint and breast prostheses. 

There is a large body of literature attesting to the chemical and physical inertness of silicone [4-12]. Recently, there has been increasing interest in the possible adverse effects of silicones used in implantation. Much of the literature describing the adverse effects of silicone has been in reference to direct silicone injection. The following discussion will review the immunologic effects of prostheses used in breast reconstruction and augmentation. 

---

Soft tissue augmentation using liquid silicone, which was initially thought to be inert, provoking little local or no systemic response, has increased and various adverse reactions have been reported, in some cases months or even years after initial exposure. For example, male-to-female transsexual patient who had received liquid silicon hip injections for cosmetic augmentation developed silicon-induced granulomas causing hypercalcemia and subsequent renal failure years after the injection [64 ]. 

With single-piece silicone implants for the finger and wrist, the stems of the implant are free to move and therefore silicone wear debris is generated as the silicone abrades against the bone. These silicone wear particles can cause an inflammatory response that results in pain, joint stiffness, loss of joint motion and soft tissue swelling (Shepherd, 2002 Shepherd and Johnstone, 2002). 

---