Breast implants are smooth or textured silicone bags that can be round (dome shaped) or breast shaped (biodimensional or anatomic). They can be filled with saline (salt water) and/or silicone gel. Implants are often referred to as prostheses. Silicone is used in many other medical implants, including pacemakers and joint replacements, as well as products such as antacids and preservatives. Research into the use of different materials to make implants is always ongoing.

All tissue expanders are filled with saline. The saline used to fill implants is like the fluid that makes up 70% of the human body. In the rare event that the implant should leak and the saline is released, the body can safely absorb it without causing any problems.

However, saline-filled implants may not have quite such a natural feel as silicone-filled implants and so they might give a less realistic reconstructed breast to touch (but not necessarily in look). They are also more likely to leak and deflate. Saline-filled breast implants may be more likely to wrinkle or ripple, particularly in thinner women.

Silicone implants are very commonly used in the UK. The silicone gel filling gives a more natural feel to the reconstructed breast. There are two main types of silicon implants:

• Most of the newer implants are made using a firmer type of silicon called cohesive gel. The more solid, jelly-like gel remains contained if the shell ruptures.
• Soft implants are filled with a semi-liquid type of silicon; this is the softest implant available and is less prone to wrinkling. It feels more natural than some other types of implants.

There have been some concerns about possible health risks if silicone leaks from the implant. If a silicone implant ruptures, this means that silicone will leak through its shell, but this usually stays in the area around the implant. However, most surgeons recommend that a ruptured implant is removed.

Implant rupture is different from implant bleeding. Implant bleeding is where there is a leakage of a small amount of silicone through the implant shell, which then can leak around the implant. Leakage of a small amount of silicone rarely causes problems and needs no action. If there is a lot of leakage, your surgeon may recommend further surgery.

Over the years there have been concerns that silicone implants can cause some illnesses/symptoms and even cancer. Women have reported symptoms such as muscle spasms and pain, swollen and painful joints, rashes, changed eye and saliva fluid and hair loss after having silicone implants.

However, the problems that have been reported tended to be associated with liquid silicone injections, where the silicone was injected directly into the breast, as opposed to silicone implants.  In an implant, the silicone is contained within the fibrous capsule that the body develops around the implant.

In response to these concerns, the Department of Health set up the Independent Review Group (IRG) to review the safety of silicone gel filled breast implants and their report was published in 1998. Copies can be obtained from their website at www.silicone-review.gov.uk or by calling 020 7972 8077.

The Independent Review Group’s (IRG’s) report states ‘the IRG found no scientific relationship between silicone gel implants and immune reactions. No relationship was shown between silicone gel implants and long-term systemic illness (affecting the whole body), nor with specific connective tissue disease or non-specific systemic illness.’

It is now also required that all women having 'cosmetic' surgery should be able to get free, full information about the benefits and risks. The Department of Health has produced a patient information leaflet called Breast Implants: Information for Women Considering Breast Implants, which is based on the recommendations of the Independent Review Group. Although this is not written specifically for women considering risk-reducing surgery (it is written more from the cosmetic surgery point of view), the principles discussed in the leaflet are helpful.

The Medicines and Healthcare products Regulatory Agency (MHRA) at www.mhra.gov.uk has recently revised this leaflet.

In addition to this, the MHRA has produced an information sheet that contains the latest safety information about breast implants that have been used in the UK. If safety concerns arise with any breast implants, the MHRA will investigate and issue advice to the health service if necessary.

It is important to talk through any concerns you have with your surgeon, breast care nurse, or cancer support organisation before you have an implant. If you think you would prefer to have an implant containing saline, you can talk to your surgeon about this possibility.