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.
The three types of saline-filled breast implants are as follows:
The silicone rubber shell for a saline-filled breast implant has the following general composition:
The filler is sterile saline that should conform to United States Pharmacopeia (USP) standards for Normal Physiological Saline (injection grade). 2
The three types of silicone gel-filled breast implants are as follows:
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:
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
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