For most women, the skin that remains after a mastectomy can be stretched or expanded to make room for an implant. To stretch the skin, the surgeon inserts a balloon-type device called a tissue expander under the chest muscle. The expander has a port (a metal or plastic plug, valve, or coil). The port allows the surgeon to add increasing amounts of liquid over time (about six months), without extra surgery. Gradually, your skin and soft tissue are stretched to achieve your desired appearance. The tissue is actually stretched a little beyond your desired size, to create a natural droop.
When stretching is completed, the expander is removed and usually replaced at the same time with a permanent implant. The final breast implant is a silicone bag that contains either saline or silicone gel.
Once a breast implant is in place, scar tissue forms all around it, forming what's called a tissue capsule. Most of the time, these tissue capsules are soft-to-firm, and unnoticeable. However, less than 15% of the time, a hard capsule forms that can be painful and distort the breast. In these cases, a surgeon can break up the scar tissue and, if necessary, replace the implant.
If you have radiation therapy to the breast area, the risk of scar tissue and hardening around the breast implant increases to 40–50%.
Massage and exercises may reduce the risk of forming a hard capsule (with or without radiation). You can ask your surgeon to show you how to massage the implant and the area around it, firmly but gently.
An implant has a small risk of riding up the chest, so you may have to massage it down into place.
Occasionally, implants leak fluid. The chance of your breast implant leaking increases over time. Most implants that have been in place for 10–15 years have some leakage, but it's usually insignificant.
You may be able to tell if your implant leaks, because your breast may get smaller. A small leak of a saline implant can't be detected. Leaking saline is harmless.
Even a small leak of a silicone implant can show up on an MRI (magnetic resonance imaging) scan, or sometimes on a regular X-ray. While this isn't necessarily dangerous, it can lead to complications that you'd rather avoid. If you suspect a silicone implant is leaking, have it checked and, if necessary, replaced.