If Silicone is "Inert", Why Does the Body Create a Capsule?

The term inert simply means that the body doesn't interact with the slicone implants. Any foreign object, be it a titanium plate, ceramic joint, or breast implant is walled off by the body. The body simply forms a scar around it, but it doesn't interact with it.  I hope this clarifies.

The body tries to wall off any implant that is inserted.  This tissue, which is a sort of scar tissue, is called a capsule when it forms around a breast implant.  The shell of both saline and silicone gel implants is made of silicone.  Silicone is an inert material - it does not tend to react chemically to the body tissues.  It also forms around pacemakers and artificial joints, including implants made of other materials.

So it is not really the silicone that is causing the formation of the capsule but rather the physical presence of an implant.  Capsules are normal.  We consider them abnormal, "capsular contracture" when they squeeze tight on an implant deforming it into a sphere and causing discomfrort.  This problem is treated with an open capsulotomy.

Hello Jones,

The formation of a capsule after breast augmenatation is the equivalent to how your skin heals after it has been cut. Your body produces collagen and forms new blood vessels to close the wound.  The only difference is that a fresh layer of skin cells covers the surface of the scar (epidermis) in the case of a skin injury.

Inert means that there is no reaction over and above the normal healing process.  An example of bioreactive (non-inert) events would include exposure of your tissues to a caustic chemical, bacteria, or non-self tissue like a donor organ.

The formation of a scar capsule around a breast implant is idenical to the healing process that would occur with the placement of a metal or glass object into the body.

I hope this explanation has been helpful for you.

Your body reacts to all foreign object differently. If it is comes from living tissue, your body will mount an attack against it. If it is inert, it will allow you to live with it but since it is foreign, your body reacts by "walling it off" or making a capsule. This goes for metal, silicone, or anything that is not rejected. The properties of silicone have been well studied and the implant companies continue to develop better silicone. The current silicone shell causes your body to make a soft capsule around it thanks to its cross-linking.

Silicone is inert, but it is not part of your body. Our bodies are designed to protect themselves from whatever foreign body is inserted into it - silicone or not. Any implant will form a capsule. The silicone is inert in that it doesn't incite the capsule formation - just the presence of something in the body will do that. The body is merely protecting itself from potential harm - an evolutionary trait. The problem with a breast capsule is when it begins to contract -  and then it is still not a product of the silicone, but some stimulant within the capsule itself, blood or bacteria. 

Unfortunately, we still don't fully understand the specific reasons behind how or why capsules form, but we are getting closer. This is a risk that all patients must accept before undergoing a breast augmentation. 

Best of luck,

Vincent Marin, MD
San Diego Plastic Surgeon

The body will form a capsule around any foreign body in your body from breast implants to pacemakers to a splinter. It is merely your body's way of identifying that the implant is foreign and isolating it. Generally, these capsules are thin and do not present any problem. With breast implants however, the body can sometimes continue to form the capsule, making it thicker and tighter.

Your body forms a natural barrier around inert implants.  This is like amost other implants used. The tissue ca not grow through the implant that is whay a capsule forms.