There is a myth floating around the general community about this one. Often patients will present to their plastic surgeon stating, “It has been 10 years and I was told I need to have my breast implants replaced”. This is not necessarily the case. Breast implants are not like tires which should be rotated every few thousand miles. The only reasons that implants need to be replaced is if there is are problems related to the implant. These problems can range from rupture, capsular contracture or implant displacement. The rates of these complications varies depending on the type of implant. The good news is that in the event an implant does need to be replaced, implant manufacturers currently replace both saline and silicone breast implants at no charge and will sometimes cover surgeons fees as well.

Silicone implants

Silicone breast implants have been around since the 1960’s. There have been four generations of these implants. The ”first generation”silicone implant was developed by Dow Corning. These were fairly thick shelled with fairly cohesive silicone. The desire for a more natural feeling implant was the impetus for the creation of the“second generation” in the 1970’s. These had a thinner shell and more liquid silicone. These had a high rupture rate and high rate of silicone “bleed” through the thinner shell leading to complications such as capsular contracture. The “third generation” was created in the mid 1980’s with a thicker shell and again a more cohesive silicone gel contained within this shell. These are the silicone prostheses currently used in the United States for breast augmentation. They were approved by the FDA in November 2006 after the “FDA has reviewed an extensive amount of data from clinical trials of women studied for up to four years, as well as a wealth of other information to determine the benefits and risks of these products,” said Daniel Schultz, M.D., Director, Center for Devices and Radiological Health, FDA. “The extensive body of scientific evidence provides reasonable assurance of the benefits and risks of these devices”. The “fourth generation” of implants is the “gummy bear” implants which are not yet approved by the FDA for use in the U.S, although used extensively in Europe. These have an even more cohesive silicone to provide a more form stable silicone and presumably less risk of rupture.

Rupture:

Determining the rupture rates of modern silicone implants is difficult because of the variety of types of implants currently in play. A few studies looking only at the currently used 3rd generation implants would suggest that the rupture rates are around 15% at 10 years. The information used by the FDA for approval of these implants showed a 0.5% rupture at 3 years. This is probably a little misleading as the risk of rupture increases with the age of the implant. Most studies using MRI data would suggest that most 2nd generation implants were ruptured by 10 years. Many of these were “silent ruptures” without symptoms. Only after there is enough experience with the newer generations of implants will their long term rupture rate be determined. Based on the cohesiveness of the implant, improved technology and durability of the shell, it is expected that these will have an improved rupture rate.

There is some controversy as to whether an implant which has ruptured “needs” to be removed. Many women have “silent ruptures” that cannot be detected by symptoms or physical exam. The FDA recommends MRI testing at 3 years after placement of silicone implants and every 2 years thereafter. In reality, this is an expensive proposition and few surgeons or patients follow this recommendation to the “T’. In reality, there are many women with silicone implants whom do not know that they have a rupture. Certainly if there is a diagnosed rupture either on physical exam, mammogram, or MRI – the FDA recommend that it should be removed as it is a failure of the device. There are a few studies that show increased symptoms such as fatigue, memory loss, fibromyalgia, and joint pain in patients with ruptured silicone implants as compared to controls. Many patients report that these symptoms resolve after removal of the implants. There are also reports of anti-silicone antibodies in the bloodstream in patients with ruptured implants and migration of silicone through the lymphatics. This is still an ongoing source of controversy. Where there is controversy, better to be on the side of patient safety and most plastic surgeons recommend removal of diagnosed ruptured silicone implants.

Capsular contracture:

Another relatively common reason for implant removal and replacement is capsular contracture. This is a hardening of the capsule, which is the envelope the body creates around the implant. Usually the capsule is soft and unnoticeable. When contracted it can be firm, distorted or even painful. Causes of capsular contracture are not entirely known but factors such as infection, silicone bleed, and hematoma seem to be involved. In Mentor’s core study of 3rd generation implants the contracture rate at 3 years after augmentation was 8.1%. This is much more common at three years than rupture. There is less controversy regarding the “need” to have the implant removed in cases of capsular contracture. Generally, this is performed if it is severe enough that the patient would like to have the implant removed and replaced. Sometimes conservative therapy with Accolate (an oral medication) can be effective.

Again, the long term data regarding capsular contracture in these 3rd generation implants is lacking. The post-approval studies which are ongoing will help to clarify some of these risks.

Saline Implants

Saline breast implants have a similar silastic outer shell to the silicone implants but the fill material is saline instead of silicone. These have been shown in prospective studies to fail at a rate of around 3-5% at 3 years and 7-10% at 5 years. This is roughly approximately 1-2% per year of implantation. With saline implants there is no fear of the “silent rupture”. If the implant fails it simply deflates and the procedure to exchange it for a new implant is usually fairly simple and can be done under local anesthesia. Because the implant filler does not hold its shape as well as cohesive silicone, there is a greater likelihood of a “fold flaw” (kind of like the crease in a newspaper). The repetitive folding is though to wear out the implant and can lead to a higher risk of rupture. The “fill valve” is another potential source of increased risk of implant rupture in saline implants relative to silicone implants. There is a documented decreased risk of capsular contracture with saline implants relative to silicone implants. Newer generations of silicone implants will hopefully have decreased risk of contracture due to the cohesive material causing less “bleed” of silicone oil.

In conclusion, the risk of failure becomes higher the longer an implant has been in place. According the the FDA and the package inserts from the implant manufacturers, implants are not meant to be a permanent device and most patients will need to have them replaced at least once. For saline implants, so long as they do not rupture or cause problems, they never need to be replaced. The same is true for silicone implants, however there is the risk of the “silent rupture”. The FDA recommends frequent MRI studies to diagnose the silent rupture. This is cost prohibitive for many patients. There may be an recommendation to have silicone implants replaced at a regular time interval when the results of the post approval study come out. For now, they should be replaced only if they fail.

Gummy bear implants are the newest generation of silicone breast implants used for breast augmentation. They are otherwise known as form stable cohesive gel implants and are used for breast enhancement frequently in Europe and South America. They were invented in the early 1990’s. They are not yet FDA approved for use in the United States aside from clinical studies. These implants were developed with two goals in mind: 1) decrease the gel bleed and associated problems in breast augmentaton from more liquid silicone implants and 2) control the shape of the breast in breast augmentation.

Silicone can be cross-linked to alter its form from a thin liquid to a firm, solid, stable mass. The cohesive gel implants have been developed with a greater degree of cross-linking than previous implants. Memory gel implants fall somewhere in between older generation silicone and form stable cohesive silicone gel implants. These are the silicone implants that we currently use for breast augmentation in my practice and I and have been quite happy with the shape, feel and low complication rate.

1. Mentor – Contour Profile Gel (CPG) implant
2. Inamed/ Allergan – The style 410 was the original cohesive implant. These are sized based on volume, height, and projection with 12 possible shape choices for each size.
3. Silimed/ Sientra – Silimed cohesive gel implants.

The purported advantages of form stable implants over current silicone gel implants include: (it is important to note that these are largely theoretical as there is no long term data as the implants are relatively new)

• Improved breast shape – the breast implant can hold its shape and effect the overlying tissue
• Less capsular contracture – capsular contracture is in part due to silicone “bleed” from the breast implant. There is theoretically less “bleed” in a cohesive gel implant.
• Decrease risk of implant rupture – Breast implant rupture is often caused by a “fold flaw” in the implant. This is an area of repeated folding on the breast implant that eventually causes it to wear out. The gummy bear implants may have decreased folding due to their form stable nature.
• Decreased risk of rippling of the breast

Form stable cohesive gel implants have their disadvantages as well:

• Increased cost
• Feel – they are firmer than memory gel implants.
• Longer scar – the implants are not able to be squeezed through the same size of incision as other silicone implants
• Possibility of rotation. The implants are “anatomic” or “tear-drop” shaped and there is a possibility that the implant could rotate early in the healing process leading to an unusual shape.
• Difficulty with secondary surgeries such as removal and replacement of implants due to the textured surface of the implant causing ingrowth of tissue onto the implant capsule

My best guess is that when these implants hit the market in the United States, they will make a big splash. There will likely be a 2-3 year period of time where a patient will feel that they are compromising on the results if they do not use the new implants. We as plastic surgeons will gain experience with these implants and we will figure out who would benefit most from these implants which will likely be a small percentage of the population. When this will occur, is still open but it looks like a couple of years still.