In a free flap reconstruction, skin, fat and sometimes muscle from one part of the body is transferred to the breast area. The skin and fat is completely removed from the original area and reconnected to a new blood supply using microsurgery. This involves rejoining arteries and veins that are only 2–3mm in diameter, using a 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. This is very specialised surgery and is done by plastic surgeons. These operations usually take about six to eight hours.

This uses the same skin and fat from the lower abdomen as the pedicle TRAM 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 doesn't have so far to flow in and out of the new breast. It is possible to make 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 usually necessary to repair it with a mesh to prevent hernias and bulges.

TUG stands for tranverse upper gracilis. This is a relatively new operation suitable for women who are slim and have small breasts. It uses tissue from the upper inner thigh, including some of the gracilis muscle. The tissue is removed and attached to the breast area using microsurgery. The scar is quite long but it is well hidden as it is at the top of the leg. Sometimes there can be a problem with fluid building up in the wound area (seroma).

Perforator flaps are flaps of skin and fat with an artery and vein for blood supply. No muscle is taken. Most perforator flaps are free flaps. A pedicled perforator flap may be used to correct a dent or defect in the breast, or to enlarge the other breast.

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 this can change the appearance of the reconstruction.

These operations take longer than a pedicled flap (6 to 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% of women who have these procedures.

There are 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. 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 doesn't 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.

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.