Fat grafting, also known as autologous fat transfer, is a technique for breast reconstruction in which excess fat is removed from one part of the body by liposuction, and transferred or “grafted” to another part of the body with cannulas. The most common sites for fat graft harvest are the abdomen, flanks, legs, and back.
Unlike flap transfer, in which tissue such as skin and fat is transferred with a blood supply, fat transfer does not involve any relocation of a blood supply. The fat can only survive if the nutrients spontaneously float across the cell walls by osmosis. The fat needs to be specially processed to remove all of the impurities – either by washing, centrifuge, or filtering. Since there is no blood supply for the fat, about 30-50% of the fat typically does not survive the transfer process.
We routinely use fat grafting in a second stage to improve outcomes after breast reconstruction. Fat grafting is well-suited for filling minor differences in shape, balance or position of one breast to obtain symmetry with the other breast. It can also be used to “augment” the breast, or make it larger. Since it is accepted that a significant percentage of the fat will be reabsorbed by the body, however, it is usually necessary to overfill a defect to reach the desired outcome. For larger defects, it is often necessary to undergo multiple rounds of fat transfer.
Fat grafting is generally an outpatient procedure. For this reason, some patients wonder if it is a “safer” operation than microsurgical free flap breast reconstruction, and inquire about using fat grafting to rebuild an entire breast. While this is theoretically possible, the reality is that the amount of fat grafting that is necessary to rebuild the entire breast can be very difficult on the body. Many rounds of fat grafting are needed to obtain the same volume of tissue as is accomplished in one operation with a flap transfer. Furthermore, many patients who have had both procedures feel that the pain from fat grafting is greater than the pain from a microsurgical free flap. In part, this is because the amount of fat that needs to be harvested for fat grafting is significantly greater than what is usually aspirated in regular liposuction. To make matters worse, if a patient has poor “take” of their fat graft, and most of their fat graft does not survive, she may “use up” the fat from her best donor sites so that she is no longer able to have flap surgery.
When it comes to autologous tissue breast reconstruction, we believe that breast reconstruction using a free flap is without a doubt far more consistent and reliable than breast reconstruction using fat graft. Free flap breast reconstruction requires fewer operations, and perforator flap breast reconstruction will generally be less painful than fat grafting or implant-based breast reconstruction. That said, fat grafting is an excellent technique when used as an adjunct procedure to improve breast reconstruction. For this reason, fat grafting is one of the most commonly performed procedures in our practice, and one in which we have great success.