uting to the large real estate boom in the area during
the 1980’s and 1990’s. The region became associ-
ated with the rise of dot-coms, new Internet-based
companies.
Impact Even after the stock market decline in 2000
linked to the bursting of the dot-com bubble, Silicon
Valley companies continued to be ranked in the top
tier worldwide for technological developments.
Further Reading
Kenney, Martin, ed.Understanding Silicon Valley: The
Anatomy of an Entrepreneurial Region. Stanford,
Calif.: Stanford University Press, 2000.
Lewis, Michael.The New New Thing: A Silicon Valley
Stor y. New York: W. W. Norton, 2000.
Lewis, Ted G.Microsoft Rising—and Other Tales of Sili-
con Valley. Los Alamitos, Calif.: IEEE Computer
Society, 1999.
Gayla Koerting
See also Apple Computer; Computers; Dot-coms;
Gates, Bill; Jobs, Steve; Microsoft; Science and tech-
nology.
Silicone implant ban
The Event As a result of health concerns, the U.S.
government declares that breast implants
cannot be filled with silicone
Date 1992
When the Food and Drug Administration (FDA) banned
silicone implants, it created enormous distrust of the health
care industr y. Thousands of women sued manufacturers
for damages.
In 1976, the FDA enacted the Medical Devices
Amendment, requiring that all medical devices be
approved for safety and effectiveness. A grandfather
clause exempted devices already in use unless their
safety was questioned. Silicone breast implants, in
use for over ten years, were therefore exempt.
In 1988, following reports of illness linked to rup-
tured implants, the FDA required the four manufac-
turers of implants to prove the safety of silicone im-
plants, giving them three years to conduct studies
and compile data. In 1992, Dow Corning provided
data from 329 studies. The FDA found the results in-
conclusive and banned the use of implants for cos-
metic surgery. Only women undergoing reconstruc-
tive surgery for breast cancer, breast injuries, or
deformities could receive silicone-filled implants,
and then, only as part of a research study.Impact By the 1990’s, cosmetic breast surgery had
become popular, as more than 1.5 million women in
the United States had received silicone implants.
Thousands of women who believed their implants
caused disease, such as cancer and autoimmune dis-
orders (rheumatoid arthritis and lupus), sued the
manufacturers for billions of dollars in settlements.
Dow Corning filed for bankruptcy to settle claims.
In 1997, Congress instructed the Department of
Health and Human Services to examine safety issues
related to silicone implants. Scientists from numer-
ous medical specialties reviewed all available studies
and concluded that there is no evidence that sili-
cone implants cause cancer, autoimmune diseases,
diseases specific to implants, birth defects, or danger
to a developing fetus.
Problems associated with implants are local to
the implant and areas affected by the surgery. The
greatest risk of silicone implants, compared with sa-
line implants, is an increased incidence of capsular
contracture (scar tissue formed by the body). All im-
plants result in some degree of contracture, but, in
some women, the appearance and feel of the breast is
so altered that surgical correction is required. Breast
implants do not last forever and will rupture eventu-
ally. When rupture is detected, surgery, with the usual
risk of hematoma and infection, is required to re-
place the implant. Rarely, rupture results in silicone
gel escaping into tissue near the breast and becoming
encapsulated by the body, resulting in a lump in
the chest, armpit, or arm. Surgical correction re-
quires removal of the implant and escaped silicone.
Although radiation therapy can cause an increase in
capsular contracture, mammography or other X rays
have no adverse effects on implants.Subsequent Events Subsequent research has failed
to show a causal relationship between silicone im-
plants and disease, but uncertainty and controversy
continue. It is possible that an undetected rupture
could result in long-term risks. More research is indi-
cated and the FDA ban remains in effect.Further Reading
Grigg, Martha, et al.Information for Women About the
Safety of Silicone Breast Implants.Washington, D.C.:
National Academy Press, 1999.774 Silicone implant ban The Nineties in America