In free flap reconstruction, areas of fat, muscle and skin from one part of the body are moved to another. The blood supply is cut and then a new blood supply for the flap is created at the area of the breast. These techniques involve microsurgery (rejoining arteries and veins that are only 2–3mm in diameter, using an operating microscope).

Blood vessels from the armpit, or near the breastbone, are used to create a new blood supply for the tissue that has been moved to the breast.

A number of different types of free flap can be used for breast reconstruction. These are very specialised types of surgery and can only be carried out by specialist surgeons with a lot of experience in these procedures. Even surgeons who carry out microsurgery may specialise in only one or two microsurgery techniques.

This uses the same skin and fat from the lower abdomen as the pedicle TRAM (Transverse Rectus Abdominis Muscle) flap, but less of the muscle is taken. Once the blood vessels are joined up, the blood supply is better than the pedicle TRAM flap because the blood does not have so far to flow in and out of the new breast. It is possible to give a larger breast using this technique and the appearance is usually very good. However, some muscle is still taken from the abdominal wall and it is still necessary to repair it with a mesh to prevent hernias and bulges.

Free perforator flaps are flaps of skin and fat with an artery and vein for blood supply. No muscle is taken. These operations are usually done by plastic surgeons, either at the time of the initial breast surgery or some months later.  Most plastic surgeons advise delaying a perforator flap reconstruction if radiotherapy is planned, as the radiotherapy can change the appearance of the reconstruction.

These operations take longer than a pedicled flap (6–8 hours) and need a hospital stay of about a week. There is a chance that the tissue in the area may die if the blood supply to the breast is not good enough and this happens in up to 5–10% of women who have these procedures.

There are now several types of perforator flaps. They are named after the blood vessel that is used.

Free DIEP flap (Deep Inferior Epigastric Perforator flap) or the free SIEA (Superficial Inferior Epigastric Artery flap)

Skin and fat is taken from the lower abdomen, but no muscle is taken. Instead the tiny blood vessels are very carefully cut out from the muscle, which is left in the abdomen. The appearance of the new breast is usually very good and it feels natural. As no muscle is taken from the abdomen, the risk of hernias or bulges is almost completely removed, so a mesh does not need to be used.

Free SGAP flap (Superior Gluteal Artery Perforator flap) or the IGAP flap (Inferior Gluteal Artery Perforator flap)

This uses fat and skin taken from the upper or lower buttock to create a new breast. It is generally used when abdominal tissue cannot be used due to scarring from previous surgical procedures or because the woman is too slim. The IGAP flap gives a softer feeling to the breast than the SGAP flap. The IGAP flap allows a larger breast size to be created and the scar is hidden in the crease of the buttock.

Flaps taken from other areas of the body

In very rare situations it may be possible to take flaps from other areas of the body where there is enough fat and a suitable blood supply.