An FDA advisory panel has recommended that silicone breast implants be allowed back on the market, 11 years after they were banned for the majority of breast augmentation procedures. The saline implants that have been used in the interim are often criticized for looking and feeling less natural than their silicone counterparts. Why have saline implants earned a bum rap?
The viscosity of the filling material is the key, since all implants use silicone outer shells. As the name implies, saline implants are filled with simple salt water, a poor analogue for the texture of naturally occurring mammary tissue. These surgically implanted sacs can feel squishy to the touch, and they tend to bounce around more vigorously—sometimes painfully so—during physical activity.
Silicone implants, by contrast, are filled with a synthetic gel, a fluid with a consistency not unlike thinned-out maple syrup. This liquid more closely mimics authentic tissue, and over time, silicone gel oozes to conform with the natural tear-drop shape of a patient's breasts. Saline implants, meanwhile, tend to retain their round, balloonish quality, and are thus easier to spot with a cursory glance. Also, saline implants are more prone to noticeable "rippling." (Makers of saline implants have tried to ameliorate some of these issues by designing so-called high-profile implants, which have less width but more "projection.")
One major advantage of saline implants is that leaks are more immediately noticeable. The viscosity of the gel in a silicone implant means that leaks are very slow and can be imperceptible for years. Though doctors remain divided over whether silicone gel can cause cancer, lupus, or other serious maladies, they generally agree that it's best to play it safe and not allow a synthetic polymer to seep into breast tissue, so silicone implants must be removed if a rupture is discovered. The longer a leak persists, the more difficult (and expensive) it can be to perform the removal and clean up the surrounding tissue. A ruptured saline implant, on the other hand, is immediately noticeable, as the fluid seeps out quickly. The saline is naturally absorbed and excreted by the body, so all the surgeon must do is remove the ruptured sac.
Implant makers have also experimented with using soy oil as a filling agent. But British women who received such implants in the mid-1990s frequently reported painful swelling, the result of leaks that produced an "emulsified yogurt-like substance," as the Independent characterized it. They have never been approved by the FDA, and no clinical trials are currently underway.