The Straight Scoop on the History of Breast Implants Part 3
Wednesday, March 3rd, 2010Surgical 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 and/or serratus fascia (submuscular). The implant is then inserted and the incision closed.
Safety, Adverse Effects, and Complications
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 body tissue or organ. These devices can be thought of as new body parts and, like our own organs, they may last a lifetime or cause frequent difficulty throughout life.
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 of a cut 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 everyone.
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:
- Grade I - None: The augmented breast feels as soft as an unoperated breast.
- Grade II - Minimal: The breast is less soft; the implant can be palpated but is not visible.
- Grade III - Moderate: The breast is firmer; the implant is felt easily, and its presence is visible.
- Grade IV - Severe: The implant is firm and often tender, painful, cool, and distorted; its presence is obvious.
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, 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 1,000,000).
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 there is no health related reason that requires removal of these particular devices in asymptomatic women.
CONTINUED ON NEXT BLOG PART 4 HISTORY OF BREAST IMPLANTS











