Saline implants are the most frequently used implants in the U.S. They vary in shell surface (i.e. smooth or textured), volume, shell thickness, profile, shape (round or anatomical), as well as expandable implants. Most saline implants are single lumen, and are filled at the time of surgery. There are prefilled saline implants, which are filled by the implant manufacturer. However, there are no pre-filled saline implants with FDA approval at this time.
The shell consists of a strong, silicone elastomer shell, and is filled with a sterile saline solution at the time of surgery. Should these implants rupture, the body will absorb the saline, much like drinking a glass of water. The sterile saline solution, used as the implant filler, should conform to the USP (United States Pharmacopeia) of Normal Physiological Saline (injection grade), which has a concentration of 0.15M and a pH of 7.2-7.4.
Saline Breast Implant Sizes
Saline implant sizes range from 120cc to 960cc. A patient wanting implants larger than 850cc will need custom implants. Currently, the only implants available for use in the United States are those manufactured by Mentor Corp. and Allergan.
Saline Breast Implants Valves
All inflatable implants have valves. There are a few types of valves: the leaf valve, the kink valve, and the diaphragm valve. The diaphragm valve is like a snap, like in clothing. The male portion at the end of the tubing snaps into the female receptor hole, incorporated into the implant shell.
The leaf valve was a flat sleeve (about 1.5" long) that a stylet (metal catheter) threaded through it. When the stylet was removed the sleeve would go flat, sealing the valve. The leaf valve had a higher degree of user trauma. If the stylet was forced hastily into the sleeve, damage could occur to the valve, thus causing leakage. Mentor and McGhan no longer use the leaf valve. Most valves are located on the anterior, or front, of the breast implant.
Spectrum Expandable Saline Breast Implants
The Spectrum Expandable saline implant, invented by Dr. Hilton Becker, in conjunction with Mentor Corp. can be used as a permanent expander, or as a "regular" breast implant for breast augmentation in general. This implant has the Becker valve, fill tube, and reservoir system. For use as a "regular" implant, the fill port and tube is removed at the time of surgery, sealing the valve. Once the fill tube is removed, you can no longer add or remove saline from this implant, as you can from most other saline implants.
For use as an expandable implant, the fill tube is left in place. A special fill port is attached to the tube, through which saline can be added or removed. Saline is usually added in 50cc increments. Once the desired size has been achieved, a minor surgical procedure is performed in your surgeon's office, during which the fill port and tube are removed. This closes the valve, sealing the implant. In the event of a redo, the incision will need to be a little longer, because the implant will have to be removed in tact, since the valve cannot be re-opened.
The Spectrum Expandables come in smooth round, textured round, and contour profile, with the valve located on the posterior surface of the implant. The Spectrum valve has 3 sealing mechanisms. As the fill tube is removed the kink valve, leaf valve and the plug offer triple protection against valve failure.
Prefilled Saline Breast Implants
PIP USA (Poly Implant Prosthesis) manufactured prefilled saline breast implants, which are breast implants filled by the manufacturer and sealed with a patch on the back. Pre-filled saline breast implants are said to be comparable to the look and feel of silicone implants, softer than "regular" saline implants, and according to many, appear to give the same, or similar, aesthetic results. This is thought to be due to the thinner shell of the PIP.
As of May 15, 2000, implants by PIP USA can no longer be purchased from the manufacturer. The FDA did not approve the PMA (pre-market application) for these implants due to the limited follow-up data available from the USDPS (U.S. Discretionary Postmarket Surveillance Study). The two major factors in the FDA panel's recommendations were that the pre-clinical and clinical data were not complete.
Clover Leaf Products produce a prefilled saline breast implant, also manufacture prefilled hydrogel breast implants, as well as cohesive gel breast implants. These implants are not available in the United States.