The first commercially available silicone was introduced by Dow Corning in 1940s for industrial wartime use. Soon after, physicians and non-physicians alike had been reportedly using liquid silicone for soft-tissue augmentation in Japan, Germany, and Switzerland.
Suffice to say, silicone was the first synthetic, permanent, soft-tissue-augmenting material used for correcting cutaneous and subcutaneous atrophies. Due to its natural texture and long-lasting duration, it was the soft tissue injectable filler of choice prior to the introduction of bovine collagen in the early 1980s.
Controversial Use in History
The subsequent decades brought controversies, criticisms, and disastrous consequences. The major problem faced by the use of silicone for soft-tissue manipulation was the proliferation of adulterated and impure substances, or substitutes made of unknown compounds masquerading as silicone. Frequent side effects and complications were on the rise—even for medical-grade labeled products—due to unregulated dispensing and the lack of common standards regarding purity, sterility, dosing, and injection protocol. The Food and Drug Administration banned the use of silicone for cosmetic implantation in 1992. However, silicone has gained approval for intraocular retinal detachment in 1997; hence, its off-label use for soft-tissue injection was resumed.
What is injectable silicone?
Silicone is a non-toxic and chemically nonreactive compound that remains structurally unaltered when exposed to a wide range of environmental conditions. It is versatile, easily fabricated, and can exist in solid, liquid, gel, and foam forms. There are various silicone polymers employed for medical use, but polydimethylsiloxane is the liquid silicone used for soft-tissue injection. Highly purified silicone products had not been introduced until the late 1960s–1990s.
How it works
There are 2 medical-grade silicone products available in the United States; Adatosil 5000 and Silikon 1000. The viscosity of silicone is measured in centisokes (cs). The numbers 1,000 and 5,000 refers to the viscosity of the product; 1,000cs is similar to the viscosity of honey. Silicone products used for soft tissue injection often have a viscosity of 350cs (similar to mineral oil) to 5,000cs. The viscosity of silicone remains stable after tissue implantation. Although limited, injectable silicone it is being used off-label as a cosmetic filler.
The mechanism of action of silicone injectable is twofold:
- Immediate volume displacement of dermal and subcutaneous tissue;
- And deposition of new collagen by inducing granuloma formation and local fibrosis.
Injectable silicone is commonly administered using microdroplet technique; 0.01–0.02ml of silicone is injected into the subdermis using a 28 to 30G tuberculin syringe. Approximately 1 month after injection, fibroblast and collagen layers encapsulate each microdroplet. Macrophages and giant cells surround these microdroplets at 3-6 months. On the ninth month, granulomatous nodules surrounded by fibrous tissues are present around the implant.
Dangers of Injectable Silicone
- Reports for silicone use in soft-tissue augmentation suggests long-standing inflammatory reactions. The extent of the reaction is unpredictable and can be severe in some cases
- There is a small margin of error in the injection technique. The accuracy of the physician is crucial for successful administration of the product. Under-correction is often employed to minimize potential adverse effects.
- Local adverse reactions include migration, infection, chronic inflammation, extrusion, ulceration, and silicone granuloma formation (late siliconoma).
- Once complications present themselves, removal of injected silicone is difficult, requiring wide tissue resection and complicated reconstructions.
- Due to the duration of effects (up to 23 years), unwanted results will also be hard to correct.
- Adulterated, impure products and other agents masquerading as liquid silicone are widely available despite the lack of FDA approval for its use.
- Silicone injectables are contraindicated for administration into the eyelids, breasts, and actively inflamed sites. It is also not recommended for pregnant women, patients with dental cavities, chronic sinusitis, and those who may predisposed to facial trauma following contact sports.
Safety Tips on Dermal Filler treatments
- Never get cosmetic fillers from unlicensed providers.
- Always consult a trained and licensed medical professional who only uses genuine brand name products on their patients.
Although many physicians have advocated the safety and efficacy of silicone injectables administered in low doses at monthly intervals, the unpredictability of potential reactions and lack of standardization in its use must be carefully considered. Currently, highly purified silicone at 1,000cs has been granted investigative status by the FDA for the treatment of facial lines, wrinkles, and HIV-related lipoatrophy. Until an FDA approval is awarded, patients and doctors must be informed of the dangers and long-standing, disfiguring, and even fatal effects of using liquid silicone injectables for soft tissue augmentation.