After a long history in breast implants and removal of the silicone breast
implant in 1992, the FDA on November 17, 2006 approved Allergan and Mentor
to again market their silicone breasts implants for primary breast
augmentation in the US. These breast implants differ from the older silicone
breast implants due to the more “cohesive” nature of the silicone, their
outer shell, as well as the styles (shapes) of implants available. Long term
studies were performed on the silicone implants to ensure their safety
leading to their reemergence on the market and ongoing studies currently are
required of the implant manufacturers to ensure the continued long term
safety of the implants.

The newest trends emerging on breast implants center on the development of
cohesive, highly cohesive and form stable gel silicone implants that have
been affectionately termed “gummy bear” implants. These are not widely yet
available in the US, but have been available in Europe since 1994 and in
Canada since 2000 through a special trial program and have been approved for
wide spread use since October 2006. Trials on these implants were also
conducted in the United States and the data are currently being accessed.

Personally, the biggest news on breast implants is the reemergence of
silicone breast implants since November of 2006. They are extremely safe,
more reliable, and in my opinion age better than the saline implants that
there is less “rippling” and palpability in the long term.

You should understand that once you undergo your first breast augmentation surgery
which IS extremely safe, you will be obligated to a few more surgeries of
implant exchange at 10-25 years from the time of breast enhancement. This of
course depends on if the patient becomes pregnant, gains or loses weight and
on the natural aging process of the breast. More importantly, the general
public should understand that the majority of woman who undergo breast
augmentation do not merely desire big breasts, but are inherently
dissatisfied with the shape and perhaps the asymmetry of their breasts and
they desire a more proportionate, shapelier, AND also a slightly larger
volume breast.

Safety

Silicone is probably the most studied implantable material available today. After over 35 well-conducted studies from many countries, it seems certain that this material does not cause disease. The results of more than 7 long-term follow-up studies show that women with implants have a reduced incidence of breast cancer than is otherwise expected in the general population. No hard evidence reveals that a broken implant is harmful. Almost all of the problems that can occur with breast implants, such as infection, hardening, extrusion, and malposition are related to the surgical procedure or the patient’s own biology, not the device.

Benefits and Contraindications

Benefits

Many social subsets of women with various motivations seek this device, especially for cosmetic purposes. However, the prototypical recipient is in her early 30s and is secure and successful in most of her activities, except for this single focus of concern. She is fully aware of the unique ambivalence that society and often family and friends have to an artificial bosom (ie, that breasts are sexy and attractive if natural but somehow frivolous and vain if sought through surgery).

Thus, in contrast to the common cliche, these women seek augmentation despite, rather than because of, social pressures. The depth of this personal need and the importance of this procedure to their sense of wholeness and self-esteem are difficult for even their loved ones and their personal physicians to appreciate. Only the woman and perhaps the plastic surgeon who hears these stories over and over again can understand the power of this need and the significant enhancement of quality of life that these devices provide.

Several surveys consistently have demonstrated that 90-95% of women who have undergone cosmetic augmentations are pleased that they did so, even if the results were less than ideal or were accompanied by complications. At the height of the negative media information in 1991, a survey of 300 plastic surgeons revealed that approximately 3% of these women made inquiries about removal due to concern over safety. Less than one half followed through, which is a measure of the great value of this operation.

This estimate is similar to the percentage of women who took advantage of the implant manufacturers’ offer of financial support for implant removal or replacement. Plastic surgeons suspected that the number of requests for removal of gel devices, usually with saline replacement, increased commensurately with the publicity over the multibillion-dollar class action settlement.

The desire of most women to replace their implants with saline (76% according to a recent study by Spear and Bowen) reflects their satisfaction with the enlargement. More recently, as reassuring research on safety has become available, interest in removal appears to have fallen significantly. Current estimates suggest that 85% of removed implants are replaced. A 1998 attempt to study explantation prospectively failed for lack of candidates. Some women, having experienced both gel and saline, are requesting a return to the gel as they felt that it provided a superior result.

More implants are sold on either coast, suggesting the existence of regional differences in body image. This becomes moot when one realizes that women in the Midwest buy larger bras on average than those that are sold on the coasts.

The anxiety generated by the 1990s media scare and dramatic litigation awards has diminished the significant psychological benefit that accrues from implants. This concern seems to be diminishing; as noted below, the number of cosmetic augmentations now appears to exceed premoratorium estimates following the significant dip of the early and mid-1990s. Therefore, all caring physicians must share the truth with their implant patients and reassure those who have chosen to accept whatever risk may be present.

Table 1. Annual Implant Sales by Pairs*
Open table in new window

*1990-1996 figures represent manufacturer’s estimates for all implant sales, including augmentation, reconstruction, and replacement. American Society of Plastic Surgeons (ASPS) and American Society for Aesthetic Plastic Surgery (ASAPS) data represent separately collected and analyzed membership statistics on cosmetic augmentation using different methodologies. These do not include patients of nonmembers, which is substantial. All numbers are approximations.

Contraindications

Aside from the usual medical conditions that would increase the risk of anesthesia, surgery and/or infection, the most significant red flag, as in all cosmetic surgery, is an unrealistic expectation. Women who are emotionally unstable or are requesting the surgery to please another person should be discouraged from undergoing the procedure. However, this should not be considered a blanket contraindication.

Each patient must be individually evaluated and a decision made as to whether the procedure will enhance the quality of her life, her sense of self, and her sense of well-being. Plastic surgeons must develop the skills to evaluate these intangibles and take the time for a proper evaluation. Because it is so subjective, do not expect 100% accuracy in predicting the outcome; guessing correctly 95% of the time is the best that can be expected.

Silicon, Silica, Silicate, and Silicone

Glossary of terms

• Silicon: Silicon is a metal in the same column as carbon in the periodic table. It is the most abundant element on earth and does not occur naturally in its pure metallic state.
• Silica: Silica in its crystalline form is common sand, marble, or quartz. It also occurs in an amorphous form. Very fine, extremely pure, amorphous silica is used as a filler to strengthen solid silicone, such as in the shell of an implant. Each grain of silica is encapsulated tightly in silicone so that even when the elastomer is abraded or torn, no silica is exposed to the body.
• Silicate: In one form, its hydroscopic properties are used to keep the contents of containers dry.
• Silicone: Substances known as silicones are polymers of silicon and oxygen. Silicone has as many forms as its carbon-based sister, oil. Like salad oils versus motor oils, not all are fit for human consumption. Dimethylsiloxane is the building block for most medical-grade silicone products, including breast implants. It can be made extremely pure and modified into products with a multitude of characteristics (see Image 1 below).

  

  The molecular structure of silicone.

Implant characteristics

Keep in mind the difference between elemental silicon and the polymer silicone. Medical-grade silicone is usually a specific, very pure polymer of silicon and oxygen with methyl side groups (dimethylsiloxane). It is one of the least bioreactive materials available for use in medical devices. The shell is made of a rubberlike membrane of fully polymerized silicone with an amorphous (noncrystalline) silica filler added for strength.

Until the moratorium, most implants used were filled with a silicone gel, the physical form of which can be likened to a spongelike matrix or 3-dimensional net filled with various chain-length silicone oils. These form a physical chemical bond resulting in a gel. The shell membrane is slightly permeable to the oils.

Depending upon the brand, age, characteristics, and environmental mechanics of a particular device, small amounts of the oil diffuse or bleed through the shell. For most implants, this is a matter of a few grams. Newer barrier coat devices introduced in the early 1980s bleed at as little as one tenth the rate of the older materials.

This leakage of silicone should be viewed in perspective. Medical-grade silicone is ubiquitous in the environment, and probably everyone in the civilized world has some form of silicone in his or her body. For example, every disposable needle and syringe, as well as intravenous tubing, is lubricated with silicone. (The FDA permits up to 1 mg/cm² of barrel surface.)

Medications in stoppered vials contain residual silicone from its use in the manufacturing process. Silicone is hydrophobic and lipophilic; thus, various amounts may be injected along with the medication depending upon the lipid characteristics of the drug used. Because insulin binds to silicone, extrapolative calculations suggest that patients with type I diabetes may inject as much as 25-30 g of silicone over a lifetime.

In its solid form, silicone elastomers are used for pacemaker coatings, tubing, prosthetic joints, hydrocephalus shunts, penile implants, and as the envelope for Norplant and other implanted drug delivery systems. Some testicular and chin implants are similar to breast implants, since both usually are made of a silicone gel in a silicone envelope.

More than 1000 medical products contain silicone as either a component or as a residuum from use in the manufacturing process. Silicone is a nonspecific term for a class of compounds, some of which are highly reactive or toxic. The generic term silicone is similar to the generic term oil, which can include both salad oil and motor oil. Within the subclass of medical-grade material, the formulations vary to some degree with intended use. The body may react differently to some of these formulations.

The designation methicone (as in simethicone or dimethicone) as an ingredient in any medication is simply silicone formulated to comply with FDA regulations for human consumption in items such as medication, foods, and cosmetics. Calcium carbonate, magnesia, simethicone antacid (Di-Gel), and oral simethicone (Mylicon) are examples of medications containing silicone that are marketed over the counter, even in pediatric formulations, with FDA approval. Silicones are used in lipstick, hairspray, food processing, skin creams, and cosmetics and are known to be absorbed through both the bowel and the lungs.

Biologically, medical-grade silicones invoke a straightforward, nonspecific foreign body response, resulting in typical macrophage invasion, giant cell formation, and eventual scarring. Several animal studies suggest that relatively huge volumes of gel injected into the peritoneal cavity of rodents may stimulate an immune response. This is not observed with the oil or solid elastomers. It can be demonstrated only by emulsifying the gel, a condition not seen in the implant. Intact gel does not lend itself to these test procedures.

Despite the many reports in the media, exhaustive evaluations by multiple prestigious scientific bodies such as the Institute of Medicine, the British Ministry of Health, the Spanish Government, a committee of the European Union (EQUAM), Harvard University, the Mayo Clinic, and multiple panels of experts established by various courts have confirmed that no evidence exists of any known or new systemic illness definitively attributed to silicones.

CONTINUED ON NEXT BLOG ON THE HISTORY OF BREAST IMPLANTS PART 3

The following is an article by Gary S Brody, Professor Emeritus, University of Southern California, Keck School of Medicine.

I hope you find this article interesting and informative on the history and development of breast implants and of silicone use in breast implants. It will be divided into 4 parts on my blog page. It is important to know and understand the controversy that centers around breast implants and especially silicone breast implants.

History of Breast Implants

The number of women in the United States who have breast implants is unknown, but current estimates derived from national surveys range up to more than 6 million. This represents more than 5% of the adult female population. The American Society of Plastic Surgeons (ASPS) collects information annually on plastic surgery procedures performed by its members. In 2008, approximately 307,000 women received breast implants for cosmetic breast augmentation and 111,000 for reconstruction of congenital or postmastectomy deformities. These data do not include those procedures (mostly cosmetic) performed by non plastic surgeons such as otolaryngologists, general surgeons, gynecologists, and others.

Following adverse publicity in the early 1990s, interest in the procedure fell significantly, especially for gel-filled devices, but it seems to have recovered incrementally. According to the ASPS, in 2008, 53% of total breast implants were filled with saline; 47% were filled with silicone.¹

Prior to 1963, various plastic foam materials were used; for breast augmentation, however, it became apparent that the air cells would collapse and, combined with tissue ingrowth, shrink and harden the device. These materials were wrapped in plastic film to minimize this effect to no avail. Amazingly, some of these implants were so well tolerated that they have stayed in place to this day.

The modern silicone breast implant has been available since 1963 and has gone through an evolution of change and improvement. Several types of devices, with many variations, shapes and styles within each class, are now available or under testing for US Food and Drug Administration (FDA) approval. Basic to all implants is a silicone rubber (elastomer) shell, which can be single or double, smooth or textured, barrier-coated, or covered with polyurethane foam. The foam-covered devices have not been available in the United States since 1990 but are still marketed in Europe.

The contents are either factory-filled with silicone gel of various consistencies or inflated at surgery with normal saline. One brand that was manufactured overseas was prefilled with saline at the factory. It was briefly marketed in the United States but was later withdrawn when the FDA denied approval.

The double-lumen devices consist of concentric balloons that contain silicone in one chamber and saline in the other. The only one still in use is the Becker, which has an outer layer of gel and an inner balloon that is valved to permit postoperative gradual inflation with saline. This is termed a “permanent tissue expander,” since it permits gradual and temporary overinflation to create the pocket and then can be left in as a permanent implant after the size is adjusted appropriately. At this writing, the Becker devices are not generally available in the United States until current FDA mandated studies are evaluated.

In 1990, the FDA placed a moratorium on gel-filled implant use for cosmetic augmentation. They remained available for reconstruction and replacement, but mandated extensive record keeping, follow-up, and IRB approval were required for use. In 2006, after extensive study and analysis, the FDA deemed the device safe for all augmentation and reconstructive purposes, but they continue to require tracking of patients.

Saline Implants

Saline filled implants are available as empty silicone balloonlike devices to be filled with normal saline at the time of surgery. This permits subtle size adjustments to compensate for asymmetry between the breasts. They are less popular than silicone implants, as they often may have a less natural feel. If the patient has very little breast tissue or only a skin covering after mastectomy, unsightly wrinkles and folds of the device may be visible on the breast. This is more common when the surface is textured.

Silicone Gel Implants

Three generations of basic design of this device have been created, with many variations within each type.

First generation

The first models to be marketed had envelopes of thick, smooth-walled silicone elastomer made in 2 sections, filled with a viscous silicone gel material (dimethylsiloxane) and glued together. They were available in only three sizes: small, medium, and large. In the first few years, surgeons believed that the device required attachment to the tissues to prevent migration. Scar ingrowth for fixation was accomplished by patches of material (eg, Dacron mesh or perforated silicone) attached to the back of the device or by an outer covering of polyurethane foam. The Dacron and silicone patches were subsequently found to be unnecessary; they actually detracted from the quality of the result. Some patches or tabs created a stress point that led to tears of the envelope. Fixation patches were eliminated in the early 1970s.

Second generation

Manufacturers varied the gel consistency and shell thickness in an attempt to improve performance. Beginning in the mid-1970s, the shells were made thinner and the gel less viscous (ie, more “responsive”), primarily in an ill-conceived attempt to control hardening from scar shrinkage (capsular contracture.) This trend reversed in the early 1980s when it was recognized as not effective in reducing contracture and as resulting in a more fragile device. Most were broken 10 years later.

Third generation

New formulations of the shell and gel contents became available that were stronger and had a second barrier coat of diphenyl silicone. This coating almost totally eliminated so-called “gel bleed” or diffusion of small amounts of the silicone oil through the implant shell. The gel content also was made more viscous and cohesive.

In 1989, textured-surface shells that many surgeons hoped would minimize the incidence of unwanted firmness from capsular contracture became available. Recent studies are somewhat confusing regarding whether this was effective. The textured implants had the disadvantage of a higher rupture rate than the more traditional smooth shells and often produced visible wrinkles in the breast in women with very little overlying tissue to mask the ripples. Because of these shortcomings and lack of solid evidence that these devices were softer, they have become much less popular in recent years.

Polyurethane-covered implants

In the late 1960s, a variation of the device was developed containing a polyurethane sponge coating over an otherwise standard gel-filled implant. Although the coating originally was planned as a fixation layer, many surgeons came to believe that the foam cover resulted in a decreased incidence (or at least a delayed onset) of capsular contracture. These implants also evolved in shape and design, culminating in the early 1980s with the Meme and Optimam styles. In April 1991, the manufacturer voluntarily withdrew the foam-covered implants from the market.³

One style, the MemeME, had a unique construction. It had no true shell, but a skin of sorts was formed in situ by spraying the surface with silicone containing extra catalyst prior to curing. This increased the crosslinking of the surface to create a shell-like membrane. The polyurethane foam was then shaped and sealed over the surface. Implants of this particular type were known to occasionally extrude some of their gel contents through the foam when squeezed. This is a possible explanation for reports of blood being found within the substance of the gel in apparently intact implants. The MemeME model was marketed from 1983-1988.

Other filler materials

While silicone remains the only available shell material, new filler substances were in use in Europe and South America and, at one time, were under development or in experimental trial in the United States. Various hydrogels and a pure form of triglycerides were the 2 main formulations. The major advantage of the triglyceride formulation (Trilucent) was that it had a Z number (measure of radiolucency) similar to that of fat, thus resulting in little or no compromise of mammography. Another fill substance, polyvinyl pyrrolidone in saline, was briefly available, under the trade name Misty Gold. None of these products is currently available in the United States. At this time, only silicone gel or saline-filled models are available for use in the United States.

Recent developments

In late 2006, a new formulation of silicone gel filler called MemoryGel (Mentor Corp, Santa Barbara, Calif) gained FDA approval. This gel implant is thicker and more cohesive so as to minimize gel spread in the case of rupture and to resist scar shrinkage that would deform its contour. When cut, the gel retains its shape and doesn’t run. This device has a doughy feel to it.

Currently available devices in the United States are saline- or silicone-filled implants with either textured or smooth surfaces. They come in round or tear drop shapes with a choice of 3 different projections. Only 2 companies, Mentor Corporation and Allergan (a successor to McGhan and Inamed), have FDA approval to market these devices in the United States.

The implants produced currently are much improved devices compared to earlier units. The shell is still made of an outer layer of a mix of dimethyl siloxane and amorphous silica with an inner barrier coat of diphenyl siloxane to minimize silicone gel bleed. The shells, on testing for breakage, exceed the American Society for Testing and Materials (ASTM) requirements by more than 300%. The gel is more cohesive, varying from a standard 60% crosslinking to 80% for the more cohesive type nicknamed “gummy bear” (because of is consistency similar to the candy).

As evidenced by sales figures prior to the moratorium, and now following their release for cosmetic purposes, approximately 80-85% of surgeons and patients prefer the quality of results obtained by gel implants, making them the implants of choice. In 1997, sales figures for Europe, where usage was unrestricted, show a distribution of 70% for gel, 15% for saline, and 15% for alternate fills such as triglycerides (then still available) and hydrogels for cosmetic use.

CONTINUED ON NEXT HISTORY OF BREAST IMPLANT BLOG PART 2

Before Breast Augmentation

After Breast Augmentation

There are many different sizes and shapes of silicone and saline breast implants which are very safe that can give you very natural looking breasts. You can be pretty much any size you want to be with breast augmentation.

Dr Koo will show you many many before and after pictures of women who have had the same procedure that have breasts that resemble yours. She will also show you pictures of women who have similar height and weight as you to give you a better idea of the shape and size you might want for yourself.  Dr Koo will spend as much time with you as you want to determine what is the perfect breast implant size and shape is for you and whether you should have the breast implant placed under the muscle or breast tissue. These choices are determined by the shape of your breasts, how much breast tissue you have, how low or high you want your breasts and the incision she chooses for your breast augmentation.

She will be able to create the sexiest yet most natural looking and feeling breasts for you with the perfect breast implant for your body.

The first thing you should know about breast augmentation is that this will not be your last surgery. You will need to plan for at least 2 or 3 more surgeries in your lifetime depending on your age at the time of your first breast augmentation. Your breast implants will last approximately 20 years whether it is silicone or saline. Dr Koo recommends that you change the silicone implant at about the 20 year mark or when there is a change in the way the breast implants feel or look.

If your saline breast implants rupture, you will notice a change in size within 3-5 days of the rupture. The saline will be absorbed by your body and the ruptured side will be smaller than the breast that has not ruptured. You should then have BOTH breast implants changed and start at time zero with both breasts.

If you have silicone breast implants, you may not have to change your implants until there is a change in the way your breasts look or feel. Dr Koo’s recommendation is to change the breast implants at approximately 20 years or before if there is a problem. If, however, you are not having any problems, you can wait until there is some change.

Mammograms are recommended yearly starting at age 40. If you have a family history of breast cancer you might need a mammogram as early as age 30 or 35 depending on your breast examination. Dr Koo always follows her patients on a yearly basis without further charge and encourages women to see her every year to teach them how to examine their breasts and to educate them as to how their breasts feel with implants in place.

Dr Koo places the implants over and under the muscle and decides which is the perfect position for you depending on how much breast tissue you have, where your breasts fall in relation to the inframammary crease, and your desire to have higher or lower breasts. There are many many subtleties of breast augmentation and the type and placement of the breast implants that Dr Koo will determine for you and guide you for creating the perfect, sexy natural breasts that can be created with breast implants.

Call Dr Michele Koo, MD, FACS, Board Certified Plastic Surgeon, St Louis, Missouri for the most natural looking and feeling breast implanted breasts possible. She will take care of you throughout the years.

For more information about breast feeding and breast implants and the need for breast lifts after children and as the breasts age with implants in place, see the next blog coming up.