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FDA Breast Implant Consumer Handbook - 2004
DEVICE DESCRIPTION
Breast implants may vary in shell surface (smooth versus textured), shape (round
or shaped), profile (how far it sticks out), volume (size), and shell thickness.
The primary parts of most breast implants are a shell (otherwise known as the
envelope or lumen), a filler, and a patch to cover the manufacturing hole.
With respect to the shell design, while most breast implants are single lumen
(just the shell), some breast implants are double lumen (one shell inside another
shell). With respect to the filler, some breast implants are manufactured with
a fixed volume of filler, some are filled during the operation, and some allow
for adjustments of the filler volume after the operation.
It should be noted that tissue expanders, which are silicone shells filled
with saline, are regulated by FDA in a different way than breast implants. This
is because tissue expanders are intended for general tissue expansion for a
maximum of 6 months, after which, they are to be removed. Because of this, the
design specifications (e.g., thinner shell) and preclinical testing recommendations
are different for tissue expanders than for breast implants. Tissue expanders
are not to be confused with the third type of double lumen silicone gel-filled
breast implants described in the Silicone Gel-Filled
Breast Implants section below. The third type of double lumen silicone gel-filled
breast implant is a permanent implant (not intended to be removed) that allows
for limited tissue expansion but is regulated by FDA as a breast implant. See
that section for more details.
Below is information specific to saline-filled, silicone gel-filled, and alternative
breast implants.
Saline-Filled Breast Implants
The three types of saline-filled breast implants are as follows:
- One type is a single lumen implant that is filled during the operation with
a fixed volume of saline through a valve. There are no adjustments of the
saline volume after the operation.
- A second type is a single lumen implant that is filled during the operation
with saline through a valve. This type of implant allows for adjustments of
the saline volume after the operation.
- A third type is a single lumen implant that is prefilled by the manufacturer
with a fixed volume of saline. There are no valves for filling during the
operation or for adjustments of the saline volume after the operation.
The silicone rubber shell for a saline-filled breast implant has the following
general composition:
- cured polymeric (large) silicones
- approximately 20% of finely powdered silica that is tightly bound to the
silicone polymers
- small amounts of smaller silicones
- minute amounts (parts per million) of metals, including a metal catalyst
(usually tin, zinc, or platinum) (A catalyst is something that causes a change
in material.)
- traces of readily evaporating materials (volatiles), such as xylene and
other organic compounds.
The filler is sterile saline that should conform to United States Pharmacopeia
(USP) standards for Normal Physiological Saline (injection grade). 2
Silicone Gel-Filled Breast Implants
The three types of silicone gel-filled breast implants are as follows:
- One type is a single lumen implant that is prefilled by the manufacturer
with a fixed volume of silicone gel.
- A second type is a double lumen implant with (1) an inner lumen prefilled
by the manufacturer with a fixed volume of silicone gel and (2) an outer lumen
that is filled during the operation with a fixed volume of saline through
a valve.
- A third type is a double lumen implant with (1) an outer lumen prefilled
by the manufacturer with a fixed volume of silicone gel and (2) an inner lumen
that is filled during the operation with saline through a valve. This type
of implant allows for adjustments of the saline volume after the operation.
A silicone gel-filled breast implant has a silicone rubber shell with the same
general composition as shown in the Saline-Filled Breast Implants
section above.
The filler is silicone gel that has the general composition of:
- cured polymeric (large) silicones
- small amounts of uncured large and smaller silicones
- minute amounts (parts per million) of metals, including a metal catalyst
(usually platinum). (A catalyst is something that causes a change in material.)
Alternative Breast Implants
An alternative breast implant typically has a silicone rubber shell with a
filler other than saline or silicone gel. The filler material may or may not
be a gel. An alternative breast implant may also have an alternative shell other
than one made from silicone rubber.
2 As a note, one concern
that relates specifically to saline-filled breast implants is the potential
for the saline to become contaminated (not sterile) with fungus or bacteria
and then released into the woman's body if her implant ruptures/deflates or
if the valve leaks. However, saline-filled implants are now generally filled
from a bag and tubing rather than from an open bowl, and this procedure may
reduce the risk of this complication.
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Updated June 8, 2004 |