You are in: eMedicine Specialties > Plastic Surgery > BREAST Breast Implants, Silicone: Safety and EfficacyArticle Last Updated: Jun 25, 2005AUTHOR AND EDITOR INFORMATIONSection 1 of 11
 
Author: Garry S Brody, MD, MSc, FACS, Professor Emeritus, Department of Surgery, Division of Plastic Surgery, Keck School of Medicine, University of Southern California Garry S Brody is a member of the following medical societies: American Association for Hand Surgery, American Association of Plastic Surgeons, American College of Surgeons, American Society for Head and Neck Surgery, American Society of Plastic Surgeons, California Medical Association, Medical Society of Virginia, and Pan-Pacific Surgical Association Editors: Christian Paletta, MD, FACS, Professor, Division Chief and Program Director, Department of Plastic and Reconstructive Surgery, St Louis University School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Saleh M Shenaq, MD†, Former Director and Founder, The International Brachial Plexus Institute; Former Chief, Section of Plastic Surgery, Methodist Hospital, Houston; Nicolas (Nick) G Slenkovich, MD, Practice Director, Colorado Plastic Surgery Center at Swedish Medical Center; Michael J Miller, MD, FACS, Professor, Department of Surgery, Chief, Division of Plastic Surgery, Ohio State University College of Medicine Author and Editor Disclosure Synonyms and related keywords: HISTORY OF BREAST IMPLANTSSection 2 of 11
 
The number of women in the United States who have breast implants is unknown, but current estimates derived from national surveys range up to 4 million+. This is more than 3% of the adult female population. An estimated 70-80% of breast implant procedures were performed for cosmetic purposes and 20-30% for reconstruction of congenital anomalies or postmastectomy defects. Following adverse publicity in the early 1990s, interest in the procedure fell almost 50% but seems to have recovered incrementally. In 1998, approximately 350,000 pairs were sold in the United States for augmentation. Before 1963, various plastic foam materials were used; 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 and styles within each class, have been created. 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 contents are either factory filled with silicone gel of various consistencies or inflated at surgery with normal saline. One brand manufactured overseas was briefly marketed in the United States and was prefilled with saline at the factory. This device was later withdrawn when the FDA denied approval. The double-lumen devices consist of concentric balloons containing 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. Gel implantsThree 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, and glued together. In the first few years, researchers believed that the device required attachment to the tissues to prevent migration. Scar ingrowth for fixation was accomplished by patches of material, such as 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 and 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 Evolution brought changes in 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 capsular contracture. This trend reversed in the early 1980s upon realization that it was not effective in reducing contracture and resulted in a more fragile device. Most were broken 10 years later. Third generation New formulations of the shell became available that were stronger and had significantly lower "bleed" or diffusion of the usually tiny amounts of the silicone oil fraction of the gel contents. The gel content also was made more viscous and cohesive. In 1989, textured-surface envelopes that many surgeons hoped would minimize the incidence of unwanted firmness from capsular contracture became available. Recent studies are somewhat confusing regarding whether this is effective. Also available are devices with removable subcutaneous fill ports, which permit some postsurgical size adjustment. The textured devices appear to have a greater rupture rate than those with smooth shells. Polyurethane-covered implants In the late 1960s, a variation of the device was developed containing a polyurethane coating over an otherwise standard gel-filled implant. Although the coating originally was planned as a fixation layer, more 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. One style, the MemeME had a unique construction. There was 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 cross linking of the surface to create a shell-like membrane. Without the silica filler, this membrane was not as strong as a regular shell. 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. While silicone remained 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 are 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 in the United States under the trade name Misty Gold. None of these products are currently available in the United States. All currently considered fill substances are designed to be absorbed harmlessly and excreted if the shell leaks or breaks. Other than time-honored silicone gel, no nonabsorbable filler is presently available in this country. Currently in clinical trials is a new formulation of gel filler that is thicker and more cohesive so as to minimize gel spread in the case of rupture. As evidenced by sales figures prior to the moratorium, approximately 80-85% of surgeons and patients preferred the quality of results obtained by gel implants. Gel devices appear to be the implants of choice for postmastectomy use. In 1997, sales figures for Europe, where usage is 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. As of this writing, because of the restrictions placed on the sale of the gel device by the FDA, these implants are available only for reconstruction or replacement under a strict protocol. The FDA has just concluded hearings in which the latest safety data on the gel implants were presented by both manufacturers. The panel of experts approved the Mentor corporation devices for cosmetic use under strict regulation and follow-up requirements but denied approval for the Inamed product. The panel recommendations are only advisory, and it remains to be seen whether the FDA will accept their advice or, as they have done before, continue the ban for cosmetic use. BENEFITS AND CONTRAINDICATIONSSection 3 of 11
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 in 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. It is sexy and attractive if it is natural but somehow frivolous and vain if sought through surgery. Thus, in contrast to the common cliché, 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 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 1990's media scare and dramatic litigation awards has diminished the significant 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*
*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. All numbers are approximations. Contraindications Aside from the usual medical conditions that would increase the risk of anesthesia 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 herself, 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 SILICONESection 4 of 11
Glossary of terms
See Printer-friendly version - the molecular structure of silicone (PDF). Adobe Acrobat Reader (stand-alone) or Viewer (browser-integrated JAVA plug-in) is required to view this document. To obtain these products for free, please visit http://www.adobe.com/support/downloads/main.html. 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 a fused, 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, varying 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. 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, and simethicone antacid (Di-Gel) and oral simethicone (Mylicon), even in pediatric formulations, are examples of medications containing silicone that are marketed over-the-counter with FDA permission. Silicones are used in lipstick, hair spray, food processing, skin creams, and cosmetics and are known to be absorbed through both the bowel and the lungs. 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. 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, a committee of the European Union (EQUAM), 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. Surgical procedure Surgery for insertion of the devices can be performed under local or general anesthesia and is usually an outpatient procedure. The incision for cosmetic insertion most commonly is made along the lower edge of the areola, in the axilla, or in the inframammary fold. For postmastectomy reconstruction, the existing surgical scar usually is used for access. A generous pocket is made for the implant in a plane either deep to the breast on the pectoral fascia (submammary) or beneath the pectoralis major, often including the serratus musculature (submusculature). SAFETY, ADVERSE EFFECTS, AND COMPLICATIONSSection 5 of 11
All of the normal risks of surgery and anesthesia can occur with breast augmentation or reconstruction. Infection, bleeding, change in nipple sensation, malposition (hyposensitivity, hypersensitivity), poor healing, anesthetic accidents, and other complications can occur at a rate that is similar to that in any clean surgery in this area on healthy patients. Concerns specific to the breast implant follow. Repeat surgery Most women who have implants achieve satisfactory results from one operation, and the implants remain indefinitely without difficulty. As many as 20% of women may need repeat surgery (often more than once). Reoperation may be required for a host of reasons, and for a few women these devices become high-maintenance items. To place this in perspective, do not expect more from an implant than from any natural tissue or organ. Any body part may last a lifetime or can cause frequent difficulty throughout life, as can these devices. Capsular contracture Often referred to as a complication, this phenomenon best is considered an adverse effect. It is the result of the normal process of scar formation resulting from the repair of separation of tissue. One would not consider the skin scar a complication despite the spectrum of final appearances. Shrinkage or shortening of a scar is a poorly understood phenomenon that varies dramatically among individuals and at different locations and directions on the same person. Contracture around an implant is probably an aborted attempt at extrusion of a foreign body. In truth, the mystery is why contracture does not occur in every instance. Contracture is the most common adverse effect of breast implants. To achieve a soft, natural-feeling result, the surgical pocket is made somewhat larger than the implant. Normal wound healing forms a scar lining on the pocket surface termed "the capsule," which, under ideal circumstances, retains its original dimensions. The oversized pocket permits full flexibility of the implant, often resulting in a breast so soft that the implant is not palpable and closely mimics normal breast mobility and softness. For reasons that are unclear and appear to be related to a particular woman's individual biology, the scar envelope sometimes shrinks and squeezes the implant, producing varying degrees of firmness. This commonly is graded on a scale devised by Baker, as follows:
Contracture can occur soon after surgery or many years later and may be symmetric, asymmetric, or unilateral. Current theory suggests that low-grade contamination by Staphylococcus epidermidis may be the initiating factor of the contracture but this is not confirmed. Capsular contracture is not in itself a health risk other than its possible interference with mammography or the risk of surgical correction if required. However, contractures detract from the quality of the results, with the severity of concern depending upon the individual patient. The best results achieve the ideal of a breast so soft that the implant is undetectable. Yet many women prefer a slightly firm bosom while for others even a severe contracture is only a minor nuisance. The amount of overlying breast tissue as padding influences both the sense of softness and the appearance. If the tissues are tight, usually the breast has a superior fullness similar to the effect of a push-up bra. The most severe degree of contracture may be unaesthetic or deformed, quite uncomfortable, and/or chronically painful. The recent innovation of texturing the implant shell initially showed promise of reducing the incidence of contracture. However, recent data from both US manufacturers have been confusing but suggest that little or no difference exists for saline implants. In contrast, the most recent information concerning gel implants demonstrates statistically less contracture in cosmetic patients (smooth 15%; textured 9%; p <0.01) with the textured variety but does not seem to make any difference in reconstruction (smooth 13%; textured 12%). An undesirable adverse effect of texturing is an unpleasant rippling of the breast surface, especially if little overlying tissue padding is present, such as in reconstruction of very small breasts. This may be visible and unsightly or just palpable and annoying, depending on the thickness of normal breast tissue and subcutaneous fat available to mask the irregularities. For most women, firmness is a more acceptable compromise than rippling, especially if it is in the cleavage area. Carcinogenesis No evidence exists that the silicone used in breast implants is carcinogenic in humans. More than 7 epidemiologic studies confirm this, at least for the 10- to 30-year periods covered by these reports. Three recent large-scale studies and 2 smaller ones have demonstrated that women with implants may have up to 30% less breast cancer than expected statistically when matched with the general population. Three animal studies show the same protective effect, and one preliminary report suggests that blood from women with implants kills breast cancer cells in tissue culture. Therefore, all evidence suggests that at least for the greater than 30-year time frame that silicone implants have been available, the risk of humans developing cancer from silicone breast implants is negligible, if not nil. Recent studies also demonstrate that 5-year survival rates are not affected by the presence of these devices. A recent study from the National Institutes of Health (NIH) demonstrated the development of myelomas in susceptible strains of rats injected with gel in their peritoneal cavities. This was not observed with oil or elastomer. Eighteen cases are now in a newly established registry at NIH. They are clustered in Los Angeles, Arkansas, and Florida (no new cases have been added since the first 18 were collected 4 y ago). Monoclonal gammopathy of undetermined significance (MGUS) is found in the serum as a monoclonal immunoglobulin G or immunoglobulin A in 1.5% of the otherwise healthy population. This is believed to have some predictive value in determining the risk of myeloma, since 16% of those with elevated levels develop the disease within 30 years (0.8%/y). A small sample of women with implants has demonstrated an elevated MGUS fraction. However, a search through 4 registries containing more than 20,000 women with more than 120,000 years of risk located only 1 case of myeloma. This information should be considered and studied further, but the evidence is too sketchy to generate alarm. A statistical truism is that "an association does not imply a cause-and-effect relationship." Polyurethane-coated implants The polyurethane coat that covered some implants in the United States before 1991 is known to slowly hydrolyze over several years into unknown breakdown products. Of concern is one constituent of the polymer, 2, 4, toluene diamine (TDA). In studies performed in the 1960s, large doses of TDA fed to highly cancer-prone rats produced hepatomas. When viewed in the light of more modern understanding, the validity of these early experiments is questionable. TDA never has been documented to be a human carcinogen, but because of this animal evidence, current law, known as the Delaney clause, requires that it be banned by the FDA for use in foods, cosmetics, and implantable devices. (Congress has recently amended this clause to make it more pertinent to scientific reality.) However, no evidence exists that TDA is formed in vivo from polyurethane. While TDA is a building block of polyurethane, it is not produced by hydrolysis, since the molecule is cleaved at the urea fraction rather than at the TDA site. An FDA advisory panel hearing held in July 1991 concluded that the probable cancer risk from polyurethane-coated implants is considered negligible ( <1 in 1 million). More recent studies have demonstrated that approximately 80% of women with these devices show traces of TDA in their urine. Traces of TDA also were found in the urine of 11% of the control group, suggesting an environmental source of the chemical. None was found in the blood of patients or controls. Again, the risk of cancer from polyurethane implants was calculated to be less than 1 in 1 million. To date, no cases have been reported in the medical literature of cancer in a woman with polyurethane implants. Because the small but real risks associated with removal are greater than the risk of cancer, the FDA has advised that no health reason requires removal of these particular devices in asymptomatic women. Cancer detection Perhaps the most significant concern regarding breast implants is the possibility of delayed detection of cancer. The implant itself is radio-opaque and variably compresses the breast tissues depending upon the particular configuration of a particular woman's breast architecture and the degree of contracture. A real concern involves the presence of an implant compromising mammography and delaying detection until the mass is large enough to be palpable. Several recent studies have shown that this appears to be only a theoretic risk since the stage of detection of the breast cancer in women with implants appears to be identical or better than that of the overall population. Mammographic techniques have improved dramatically in the last few years, enabling the mammographer to minimize the amount of breast that is hidden by an implant. Approximately 9% to more than 20% of breast cancers in all women are invisible on radiographs. Despite the increasing use of mammography, most breast cancers still are discovered by self-examination or physician examination. Many clinicians believe that the presence of an implant can increase the ease of palpation. To date, no cases have been documented in the medical literature in which a diagnosis of breast cancer was delayed by the presence of an implant. This suggests that this is a rare occurrence, at worst. The Society for Breast Imaging, the (American Society of Plastic and Reconstructive Surgeons (ASPRS), and the American Cancer Society agree that a woman with breast implants should be on the same schedule of routine mammography as other women, as follows:
However, a woman with breast implants should avoid screening clinics where only two routine views of the breast are taken. Instead, she should be referred to mammographic units accredited by the American College of Radiology, which are familiar with the special displacement (Eklund) views required for proper mammographic evaluation of the implanted breast. Ideally, the woman should try to obtain her studies at the same facility each time so that her films can be observed serially, and she should inform the technician that she has implants. Because extra views are required, the cost of the mammogram for these patients is modestly higher. Preoperative mammograms in women younger than 35 years should be discouraged. Cancers can be observed best when the breast parenchyma is mostly fat. The young breast has dense stroma, thus mammography contributes little or nothing to diagnosis of any breast disease. In addition, evidence exists that the young breast is much more vulnerable to radiation damage. For excellent patient education resources, visit eMedicine's Women's Health Center . Also, see eMedicine's patient education article Breast Lumps and Pain. Rheumatologic disorders The media and the courtroom have made much about "autoimmune disease,human adjuvant disease," or "silicone-associated disorder" (SAD). Almost every disease and symptom complex from scleroderma to chronic fatigue syndrome to multiple sclerosis and amyotrophic lateral sclerosis has been blamed on the breast implant in various anecdotal reports. More than 200 separate conditions have been listed in plaintiff pleadings as having been caused by these devices. The College of Rheumatology, American Medical Association, and FDA agree that the term "human adjuvant disease" is inaccurate and inappropriate. These disorders, if they exist, should be labeled simply "rheumatologic or immune disorders." Of those rheumatologic disorders most likely to be caused from exogenous sources, scleroderma ("sclerodermalike syndrome" is the correct term for the variants that arise from exogenous toxins), lupus, and Sjögren disease are the most probable candidates. Scleroderma is a rare disease with an estimated incidence of approximately 10,000 new cases per year in the United States. A search of the medical literature in 1995 documented approximately 130 cases of scleroderma in women who also happened to have breast enlargement. (This number includes a significant group that was injected with unknown substances such as paraffin or adulterated silicone.) Since these are rare diseases, they require large-scale epidemiologic studies to determine if a relationship is present. Currently, 31 such studies from 4 countries encompassing a cohort of more than 500,000 women failed to find a statistical relationship between any known or newly recognized disease and silicone. Recently, a panel of experts appointed to review all of the literature for the court with jurisdiction over the implant class action suit summarized their findings as follows: No association was evident between breast implants and any of the individual connective tissue diseases, all definite connective diseases combined, or the other autoimmune/rheumatic conditions. Sjögren's syndrome was a possible exception to this statement. This entity requires salivary gland biopsy to meet the published diagnostic criteria. Whether biopsy was actually performed for cases in the studies cited is unknown. The remaining criteria based on dryness of the eyes and mouth with possible immunologic alterations are nonspecific and relatively common in any population group. Thus, the accuracy of diagnosis of Sjögren's syndrome in the studies incorporated in this meta-analysis is questionable. Additionally, some claim that silicone causes a totally new syndrome (termed by some "silicone-associated disorder"), often presenting as a unique variant of fibromyalgia, which may be associated with implants. These all have been based on anecdotal reports, and no epidemiologic studies have been performed to support this claim. On October 22, 1995, the American College of Rheumatology issued the following strongly worded statement critical of claims of such new disorders: "The ACR believes that these studies provide compelling evidence that silicone implants expose patients to no demonstrable additional risk for connective tissue or rheumatic disease." Thus, of the many other symptom complexes, illnesses, and disorders claimed by patients, some physicians, the plaintiffs' bar, and the media to be due to implants, none stand up to scientific scrutiny. The intensified interest in this issue has generated a great deal of laboratory research in many centers. In some instances, an immune response has been observed in animals, while others have demonstrated positive laboratory findings in a number of women with implants. While animal studies are useful to gain an understanding of processes, extrapolation to humans is often inappropriate. None of the published material to date has presented evidence for a convincing cause-and-effect relationship with any human disease entity. Unfortunately the lay public, the media, and some physicians have equated an immune response, as manifested by laboratory tests, with disease. An immune response is not an immune disease. As early as 1989, a Plastic Surgery Educational Foundation (PSEF)-sponsored consensus panel on this subject concluded the following:
Therefore, if a relationship is present, it must occur in a small number of women who have a genetic predisposition for the disease for which no predictive test is available. The workshop participants repeatedly emphasized that assuming that the presence of an association between two findings implies a cause-and-effect relationship is flawed logic. This truism is understood poorly by most, thus easily is exploited by those who would profit from vilifying the device. In general, while publicly neutral, privately a strong air of skepticism existed among the participants concerning cause and effect. In 1991, an FDA panel of experts, having heard all of the then-current evidence that suggested a connection between silicone gel breast implants and rheumatologic disorders, concluded that "the evidence was unconvincing." At a recent NIH-sponsored workshop on silicone implants and atypical rheumatic disease (April 17, 1997), it was again acknowledged that the evidence for a relationship with known typical disease was not convincing. The participants affirmed that the diagnosis "atypical connective tissue disease" was ill-defined, especially for those disorders that rely on subjective symptoms only and are devoid of objective findings or diagnostically specific laboratory findings. The currently classified atypical disorders represent a hodgepodge of subjective symptomatology with or without nonspecific abnormal laboratory tests. They are useful for the purpose of assigning a diagnosis for record keeping, insurance, and patients' needs for labeling but should not be considered as clearly defined entities. The absence of a clear definition and classification of these vague ailments makes validating their existence impossible. A substantial portion of the rheumatology community is skeptical that such disorders even exist as defined entities. Thus, pinpointing any specific disorder as caused by breast implants is insupportable. Until consensus is reached and these disorders are defined clearly or discredited (estimated to require 10 y if started today with adequate funding), abuses and misuse of these diagnoses will continue. Interestingly, manufacturers and physicians are criticized by the plaintiffs' bar, the media, and unhappy patients for not determining whether implants cause these diseases, when the technology to do so does not exist today, let alone 10-20 years ago. Finally, several reports state that reversal of the symptomatology can occur with removal of the implants. However, the evidence to date is confusing and suggestive of a placebo effect, the natural course of the disease, or the results of concomitant treatment. MORE ON SAFETY, ADVERSE EFFECTS, AND COMPLICATIONSSection 6 of 11
Laboratory studies No specific laboratory tests provide useful information concerning the body content of silicone or TDA or the systemic consequences. Some entrepreneurial laboratories are soliciting specimens of blood, urine, or mother's milk for analysis of silicon, platinum (contained in the catalyst used to polymerize or cure the gel), and TDA or for immunologic panels supposedly useful in diagnosing "silicone-related diseases." Elemental silicon is essential to many body tissues and is normally present in blood, milk, connective tissue, and most organs. Its concentration varies widely with diet, geography, the local water supply, and the patient's beer consumption. Aside from specific tissues such as breast capsule and the breast's immediate environs, the silicon content of blood, milk, or tissue bears no known relationship to the silicone content in the body. TDA measurements represent a specific testing problem since the commonly used methodology appears to produce TDA from the test process. As early as 1992 a letter to Congresswoman Lloyd from the FDA included the following: There is no current information in the medical literature regarding the clinical utility of any test or set of tests for monitoring or diagnosing disease specifically in patients with silicone breast implants. Use of procedures described under these conditions would be classified as investigational by the FDA. A later position paper from The College of American Pathologists states the following in its opening paragraph "It is the position of the College of American Pathologists that laboratory tests measuring blood, urine, or tissue silicon, silicone, toluene diamines, or related substances are not currently indicated or useful for purposes of medical management of individual breast implant recipients." "Serum auto-antibody tests or panels are useful in the evaluation of individual patients suspected of having collagen vascular disease, whether or not they have received breast implants, but such tests provide no findings uniquely indicative or supportive of purported silicone induced autoimmune disease in implant recipients. Interpretation of such panels as 'consistent with silicone reaction' for example are not supported by the medical literature." Both of these statements remain valid as of this date. In 1994, the Centers for Disease Control and Prevention (CDC), which has authority over clinical laboratories, issued a similar statement. As in any disorder, laboratory testing should be specific for the symptom or disease. Any conclusions concerning future risks or current illness from silicone or polyurethane drawn from clinical laboratory results are spurious. Discourage patients from requesting unnecessary tests that are meaningless and may serve only to confuse or reinforce anxiety. For the most comprehensive review of all of the literature, refer to the report of the 706 panel appointed by Judge Pointer for MDL926 litigation. It can be downloaded from the World Wide Web at the MDL926 home page. Neurologic disorders A few physicians have claimed that neurologic disorders such as multiple sclerosis and amyotrophic lateral sclerosis can result from silicone "toxicity." These reports have surfaced mostly in the courtroom with very little reaching mainstream medical literature. Platinum toxicity Organic platinum compounds such as platinic acid are used in tiny amounts as polymerizing agents in the fabrication of silicone materials acid and are considered benign. However, as an inorganic salt, platinum can be one of the most sensitizing chemicals known. Claims have been made in the courtroom incorrectly attributing the same sensitizing effect observed with inorganic salts to the organic form. Broken implants and silicone spread The true incidence of failure of the gel-filled implant remains elusive for two reasons. First, the incidence of silent rupture is difficult to determine. Second, current reports in the literature are contaminated by selection bias, since they report on women who seek care for a perceived problem. Additionally, more recent publications do not separate their findings by device generation or manufacturer. An explanation of the physics of gels is necessary to understand what happens with a rupture. The gel in an implant consists of a 3-D meshlike single molecule that constitutes approximately 20% of the volume. The interstices are filled with a mix of oils of various weights that physically and chemically are bound to the matrix. Only the oil portion bleeds through an intact shell membrane. Since silicone is hydrophobic, most of the bleed remains adherent to the implant surface. Over time, a few drops are picked up by macrophages, most of which are trapped in the capsule wall. Even smaller quantities can be transported to the lymph nodes. Infinitesimal amounts have been found in the breast and surrounding subcutaneous tissue in postmortem examinations of women who have died of trauma and incidentally had implants. This is probably the result of diffusion of the oil fraction of the implant contents. None was found in the major organs. Animal experiments with radioactive silicone suggest that some immeasurable amount may escape beyond this into all body tissues but this has never been documented in humans. Presumably, if it occurs, the quantities are too small to measure. Since silicone is hydrophobic, it is unlikely to be transported by any mechanism other than macrophage migration or local diffusion. However, as noted, various silicones in minute quantities already exist in all humans. No evidence suggests that the gel contents have any different metabolic effect on the body than the solid silicone envelope or any other benign foreign body. Thus, there should be little concern with the small amount of silicone that passes through the implant shell. If an implant shell is ruptured, the escaping gel usually is contained in the surgical pocket by the scar envelope. No evidence indicates that this constitutes any kind of health hazard or has any different physiologic effect than the intact implant. Making the diagnosis of an intracapsular break without direct exploration may be extremely difficult. Mammography is rarely useful, and ultrasound may be somewhat helpful, with an accuracy rate of approximately 60-70%. MRI using a dedicated breast coil is the best diagnostic tool and in experienced hands has a success rate as high as 85%. Physical examination alone occasionally can provide a clue to the possible rupture of a broken device. Suspect rupture if a change in character of the device is present, such as new, persistent, burning discomfort on one side or a change in the softness, texture, or shape of the implant. Occasionally, when the scar envelope is torn and the shell of the implant is disrupted, the gel can be driven into the local tissue planes or adjacent breast tissue. As in all benign tumors of the breast, the tissue containing the extravasated silicone should be removed since it may mask or mimic a breast cancer. On even rarer occasions, silicone gel has been known to extend fairly far along the tissue planes of the chest wall, down into the abdomen, into the arm, or directly into the breast tissue. Isolated reports describe silicone extending into the nerve sheaths of the brachial plexus and peripheral nerves with resultant signs of compressive neuropathy or extending into the skin, resulting in induration, necrosis, and deformity. These are extremely unusual occurrences and generally are observed in women who received some low-viscosity gel thin-walled shell implants, used for a short time in the late 1970s, or had associated injections of silicone or other materials. Within 2-6 weeks, extravasated gel is trapped in a new scar capsule. The larger droplets then are invaded by strands and septa of connective tissue, ultimately subdividing the material into smaller and smaller microdroplets. This results in a granuloma, which may be firm enough to palpate. Most silicone-invaded tissues probably remain soft until an inflammatory process produces enough edema to make them palpable. Extravasation beyond the surgical pocket can produce some unpleasant physical deformities, lumps, and masses. No health reason exists to radically excise this material, except from the breast tissue (if removal would cause deformity) and possibly from nerve sheaths if they are symptomatic. Following removal of a sufficient amount to minimize or eliminate a deformity, a patient may have to accept the residual firm plaques of silicone as permanent. Fortunately, this type of major rupture with distant extravasation is extremely rare and usually is easy to diagnose. Most women become aware of a torn capsule from the associated pain or discomfort as well as from the physical presence of a new mass. At one time, the belief was held that most ruptures resulted from the then-common practice of closed capsular rupture but this is hard to document. Thus, the expected capsule tear may mask the implant disruption. However, for some, the tear may be silent or cause so little sensation as to be ignored. Prompt consultation with a plastic surgeon is recommended if rupture is suspected. Broken inflatable devices release only harmless saline, which is absorbed promptly by the body, resulting in rapid deflation. One dilemma facing the clinician is what to advise patients with asymptomatic intracapsular rupture. With the currently available evidence of gel safety, providing a medical justification for explantation is difficult unless extravasation occurs into the breast tissue, interfering with mammography or presenting as a lump. Teratogenicity and mutagenicity In the few animal studies published to date no evidence of fetal abnormalities is demonstrated. One publication anecdotally reported GI disturbances in 9 children of mothers with implants, but most experts are unconvinced by the connection. A later publication by some of the same authors showed no difference in autoantibody production in children with GI disorders born to mothers with and without implants. A recent small study in humans demonstrated no relationship. Pregnancy and lactation Using silicon levels as an indicator of silicone content, current studies show no increase in the human milk of implanted women. A small sampling of milk measured directly for silicone also has failed to detect levels any higher than the controls. Even if milk did contain silicone, the amount would be far less than an infant would receive from a dropperful of pediatric Mylicon, in which silicone antifoam is the main ingredient. This is available without prescription to treat infant gas with FDA approval. Some has been concern that mother's milk from a woman with a polyurethane device may contain TDA. The only evidence for this came from a sample in which TDA was measured in parts per billion, a level the investigator himself agreed was below the reliability threshold of the test. New evidence suggests that women with implants may be more likely to have difficulty with lactation than those without. A recent report of 42 cosmetically augmented women showed an increased incidence of inadequate milk supply over controls. This was especially true of those with periareolar insertions. The same is true for women who have undergone periareolar incisions for nonimplant surgery. The evidence suggests that lactation insufficiency is related either to congenital glandular inadequacy, usually associated with smaller breasts, or with periareolar access surgery that damages the ductal system. This suggests that the periareolar approach should be directed subcutaneously around the lower pole of the breast to gain entry to the retroglandular space rather than directly through the breast tissue, to retain the woman's prospects for nursing. Thus, despite the exaggerations published in some press accounts and proselytized by plaintiffs' lawyers, women should be generally reassured about pregnancy, birth defects, and lactation. Closed capsular rupture For women who have developed firm, contracted capsules, a technique termed closed capsular rupture can, on some occasions, result in instant relief. This involves forceful squeezing of the breast, which disrupts the scar envelope and enlarges the pocket, thus restoring softness. This has been an attractive procedure, for when it works it is simple, only momentarily painful, and instantaneous. The tear strength of the scar envelope varies significantly among women. Some tear very easily (and often painlessly) but for others the scar is so tough that it cannot be torn without applying excessive force. In still others, a partial tear can occur that can lead to a small hernia of the implant, which may result in an unsightly or radiologically confusing diverticulum. The stretching of the device into the diverticulum can produce a stress concentration or strain the shell beyond its elastic limits, thus resulting in rupture. Although the recurrence rate following this technique is high, some women find this process so easy that they have their husband or others perform it for them as needed. Unfortunately, in the patient with a broken implant, a tear in the capsule and the force used in this technique can drive the loose gel into the adjacent tissues. Closed capsular rupture is not recommended by the implant manufacturers and voids any warranty. However, it is an attractive solution to the problem of firmness when used judiciously and when the woman is appropriately informed. When it does work, it is simple and quick. The only other alternative is surgical scoring or excision of the tight capsule. All of these techniques may result in recurrence. BRIEF REGULATORY HISTORY AND RECENT FOOD AND DRUG ADMINISTRATION ACTIONSection 7 of 11
At hearings held in October 1991, an advisory panel to the FDA concluded that "there was no evidence that [silicone gel-filled breast] implants are unsafe but that there was insufficient evidence to prove safety." The panel also concluded that the device was valuable enough for both cosmetic and reconstructive patients to recommend that they be left available for all who wish them under the public health necessity provision of the law. Despite this recommendation, FDA Commissioner David Kessler announced a temporary and voluntary moratorium of gel-filled implants only on January 6, 1992. Commissioner Kessler recommended that women who already have the device and are trouble free need not have them removed, but no women should have them newly inserted. A second panel convened in February and changed their November recommendations. They advised stricter controls of this device for cosmetic purposes but full access for reconstruction under a structured "adjunct" protocol with institutional review board (IRB) approval. All women receiving implants were to be encouraged to participate in a registry, and strict study protocols were to be instituted. On April 16, 1992, Commissioner Kessler confirmed the panel's recommendations. Until the protocols were in place, limited access to the gel-filled implant was permitted under the "urgent need" provision for women whose reconstruction is in progress, for replacement of broken devices, for immediate breast reconstruction, and for other specific cases of clinically appropriate need. They are not approved for new cosmetic augmentations except under a limited experimental protocol. In September 1992, the FDA approved the "adjunct" protocol permitting use of the gel implant for all reconstructive purposes under a limited study program monitored by an IRB. More detailed "core studies" are to be instituted for a limited number of patients and investigators. These will include separate studies for cosmetic and reconstructive patients. In 2000, the FDA wrote to implant manufacturers advising them of their requirements for additional data and encouraging them to begin a final 18-month study leading to submission of a PMA. Of the two American companies making implants, McGhan Corporation has had a protocol in place for some time but only recently began to implement data collection. Mentor Corporation has submitted its PMA application and expects to begin data collection this year. Saline implants Saline devices are still available without restriction or control. In June 1994, the agency held an administrative hearing to determine the status of the clinical and preclinical studies on saline implants and to determine when to call for the PMA applications. In early 1995, they announced that the following 3 studies would be required:
Following an extraordinary cooperative effort by the FDA, the plastic surgery community via the ASPRS, and the implant manufacturers, the enrollment goal has been met, and the studies are progressing. Preliminary data reveal a deflation rate of approximately 5% randomly distributed over a 10-year follow-up period. In March 2000, the FDA assembled a panel of experts who recommended that the saline devices of both Mentor and McGhan be approved for use with provisions for postmarket surveillance. A final ruling is expected in early summer. The panel also believed that insufficient information was available to approve the prefilled saline device. IMPACT ON HEALTH INSURANCESection 8 of 11
The entire breast implant controversy continues to impact adversely on some patients' insurability since a number of carriers have excluded coverage for any breast disease if the woman has implants. Fortunately, due to the efforts of ASPRS, this practice seems to have diminished in the past few years, but isolated reports of imposition of these riders still surface. Inappropriate association of other disorders to these devices may further compromise coverage. It behooves plastic surgeons, as advocates for patients, to intervene on their behalf and act to obtain recession of inappropriate exclusions. In the last 9-10 years, the silicone gel-filled breast implant has become one of the most studied devices in medical history. Few substances have demonstrated such remarkable uniformity of results indicating such a high level of safety. In July 1998, the British Ministry of Health and European Committee on Quality Assurance and Medical Devices in Plastic Surgery (EQUAM) both published reports essentially absolving the device of causing any systemic disease. The Institute of Medicine and a select panel of experts set up by Judge Pointer to guide the class action suit have held hearings; both find no evidence that these devices cause any illness. Their only concern was the paucity of data on implant rupture, reoperation, and capsular contracture. More than 30 quality epidemiologic studies of the health consequences of implants have been performed, and none can find any evidence of health risk; this is a remarkable record. Thus, although the issue of systemic disease and cancer as risk factors for these devices should be considered resolved scientifically, it remains a political issue in many countries. Huge legal settlements; expensive, plaintiff-funded, public relations efforts; feminist and moral agendas; and a sensation-seeking press seem to drive the continued concern over safety. Table 2 outlines the status of governmental involvement in countries with significant usage of the device as of July 1998. SUMMARYSection 9 of 11
A great deal of recent safety research combined with more than 30 years of clinical experience has proven the value and relative safety of breast implants. Aside from the unique adverse effect of capsular contracture, the complication rate of this surgery approaches that of any clean elective procedure. To date, no convincing evidence exists of any systemic disorder that can be attributed to silicone. As these are man-made devices, they have a failure rate and in some women can require a significant amount of surgical maintenance. As with all natural body parts, these artificial substitutes may be subject to injury or disease and, when viewed from that perspective, have favorable risk-benefit characteristics. Table 2. Status of Implant Regulations in Selected Countries (1999)
MULTIMEDIASection 10 of 11
REFERENCESSection 11 of 11
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