Breast Augmentation - Surgical Breast Augmentation - Breast Implants

Breast Implants

For breast reconstruction and for the augmentation and aesthetic enhancement of the size, form, and feel of a woman’s breasts, there are three types of breast implant devices:

1. saline implants filled with sterile saline solution
2. silicone implants filled with viscous silicone gel
3. alternative-composition implants, filled with miscellaneous fillers — soy oil, polypropylene string, et cetera — that are no longer manufactured.

I. — Saline breast implant

The saline breast implant, filled with saline solution (biological-concentration salt water 0.90% w/v of NaCl, ca. 300 mOsm/L.), was first manufactured by the Laboratoires Arion company, in France, and was introduced for use as a medical device in 1964. The contemporary models of saline breast implant are manufactured with thicker, room-temperature vulcanized (RTV) shells made of a silicone elastomer. The study In vitro Deflation of Pre-filled Saline Breast Implants (2006) reported that the rates of deflation (filler leakage) of the pre-filled saline breast implant made it a second choice for corrective breast surgery. Nonetheless, in the 1990s, the saline breast implant was the prosthesis usual for breast augmentation, because of the U.S. FDA importation restriction against silicone breast implants.

The technical goal of saline-implant technology was allowing a surgical technique for emplacing an empty breast-implant device through a smaller surgical incision. In surgical praxis, after having emplaced the empty breast implants into the implant pockets, the plastic surgeon then fills each device with saline solution, and, because the required insertion incisions are small, the resultant incision-scars will be smaller than the surgical scar usual to the long incision required for inserting pre-filled, silicone-gel implants.

Although the saline breast implant can yield good-to-excellent results of breast size, contour, and feel, when compared to silicone-implant results, the saline implant is likelier to cause cosmetic problems such as rippling, wrinkling, and being noticeable to the eye and to the touch. This is especially true for women with very little breast tissue, and for post-mastectomy reconstruction patients; thus, silicone-gel implants are the superior prosthetic device for breast augmentation and for breast reconstruction. In the case of the woman with much breast tissue, for whom submuscular emplacement is the recommended surgical technique, saline breast implants can afford an aesthetic “look” of breast size, contour, and feel, much like that afforded by the silicone implant.

II. — Silicone-gel breast implant

The modern prosthetic breast was invented in 1961, by the American plastic surgeons Thomas Cronin and Frank Gerow, and the Dow Corning Corporation; in due course, the first augmentation mammoplasty was performed in 1962. There are five generations of the medical device technology of the silicone breast implant, each is defined by common model-manufacturing techniques.

First generation

The Cronin–Gerow Implant, prosthesis model 1963, was a silicone rubber envelope-sac, shaped like a tear-drop, filled with viscous silicone-gel. To reduce the rotation of the emplaced breast-implant upon the chest wall, it was affixed to the implant pocket with a fastener-patch of Dacron material (Polyethylene terephthalate) attached to the rear of the breast implant shell.

Second generation

In the 1970s, the first technological development, a thinner device-shell and a thinner, low-cohesion silicone-gel filler, impoved the functionality and verisimilitude (size, look, and feel) of the silicone breast implant. Yet, in clinical practice, the second-generation proved fragile, and suffered greater incidences of shell rupture, and of “silicone gel bleed” (filler leakage through an intact shell). The consequent, increased incidence-rates of medical complications (e.g. capsular contracture) precipitated U.S. government faulty-product class action-lawsuits against the Dow Corning Corporation, and other manufacturers of prosthetic breast prostheses.

• The second technological development was a polyurethane foam coating for the implant shell; it reduced the incidence of capsular contracture by causing an inflammatory reaction that impeded the formation of a capsule of fibrous collagen tissue around the breast implant. Nevertheless, the medical use of polyurethane-coated breast implants was briefly discontinued because of the potential health-risk posed by 2,4-toluenediamine (TDA), a carcinogenic by-product of the chemical breakdown of the implant’s polyurethane foam coating. After reviewing the medical data, the U.S. Food and Drug Administration concluded that TDA-induced breast cancer was an infinitesimal health-risk to women with breast implants, and did not justify legally requiring physicians to explain the matter to their patients. In the event, polyurethane-coated breast implants remain in plastic surgery practice in Europe and in South America; in the U.S., no breast implant manufacturer has sought the FDA’s approval for American medical sale.

• The third technological development was the double lumen breast-implant, a double-cavity device composed of a silicone-implant within a saline-implant. The two-fold, technical goal was: (i) the cosmetic benefits of silicone-gel (the inner lumen) enclosed in saline solution (the outer lumen); (ii) a breast-implant device the volume of which is post-operatively adjustable. Nevertheless, the more complex design of the double-lumen breast-implant suffered a device-failure rate greater than that of single-lumen breast implants. The contemporary versions of Second generation devices, presented in 1984, are the “Becker Expandable” models of breast implant device, used primarily for breast reconstruction.

Third and Fourth generations

In the 1980s, the models of the Third and of the Fourth generations of breast-implant devices were sequential advances in manufacturing technology, e.g. elastomer-coated shells that decreased gel-bleed (filler leakage), and a thicker filler (increased-cohesion) gel. Sociologically, the manufacturers then designed and fabricated varieties of anatomic models (natural breast) and shaped models (round, tapered) that realistically corresponded with the breast and body types presented by women patients. The tapered models of breast implant have a uniformly textured surface, to reduce rotation; the round models of breast implant are available in smooth-surface and textured-surface types.

Fifth generation

Since the mid-1990s, the Fifth generation of silicone breast implant is made of a semi-solid gel that mostly eliminates filler leakage (silicone gel bleed) and silicone migration from the breast to elsewhere in the body. The studies Experience with Anatomical Soft Cohesive Silicone gel Prosthesis in Cosmetic and Reconstructive Breast Implant Surgery (2004) and Cohesive Silicone gel Breast Implants in Aesthetic and Reconstructive Breast Surgery (2005) reported low incidence rates of capsular contracture and of device-shell rupture, improved medical safety and technical efficacy greater than earlier generations of breast implant device.