One topic that has attracted growing attention in the field of Advanced Breast Reconstruction is autologous fat grafting for total breast reconstruction. (“Autologous” means that the tissue is derived from the patient.) To understand what this procedure is, and how it compares to other procedures that are currently used for breast reconstruction, plastic surgeon Dr. Ergun Kocak explains the important differences between a “graft” and a “flap.”
- A flap is a piece of tissue that is transplanted or moved from one part of the body to another, based on a specific blood supply. The flap tissue, therefore, can survive on its own because it has its own, dedicated blood flow, from which it receives oxygen and nutrients.
- A graft is still a piece of tissue that is transplanted or moved from one part of the body to another, but it does not have its own blood supply. Instead, it relies on the nearby tissues to derive its oxygen and nutrients. Over time, most grafted tissues will develop their own blood flow as small arteries and veins grow in and out of the tissue. But until this happens, grafts rely completely on their surroundings to survive.
Presently, most of the autologous, or natural tissue options available for breast reconstruction utilize flaps. Examples include DIEP and SIEA flaps from the lower abdomen, GAP flaps from the buttock region, and TUG and PAP flaps from the thighs. All of these techniques are technically demanding and involve specialized training and environments to optimize outcomes. For this reason, there has been ongoing interest to develop methods that utilize natural tissue, without the need for such demanding operative techniques, such as autologous fat grafting.
So where does the fat come from? In most cases, liposuction is performed on parts of the body where fat tends to accumulate, such as the abdomen, flanks, and thighs. The suctioned fat is processed to purify the fat cells while excluding the body’s fluids and oils. The purified fat is then loaded into syringes and it is injected into the desired area.
Small and large volume fat grafting
Fat grafting can be divided into two main categories: (1) small volume and (2) large volume fat grafting. Smaller volume fat grafting has been used for many years to correct small contour deformities after breast reconstruction using other techniques such as implant or flap reconstruction. For example, it is common to have a small area of volume deficiency at the inner, top part of the breast after implant reconstruction. Fat grafting small volumes (50-100 cc) into this area adds fullness and improves the contour, making many patients much happier with the appearance of their reconstructed breasts.
Smaller volume fat grafts can also be used to improve or correct deformities of the breast which occur after lumpectomy with or without radiation. While the overall goal of lumpectomy is to conserve the breast shape and size, deformities can occur, especially if radiation therapy is added to the treatment regimen. These deformities can be very difficult to repair as there are not many flaps which are small and versatile enough to be custom-tailored to replace the tissue that was taken out with the original lumpectomy. Furthermore, using implants to increase the size might seem like an easy fix, but this approach is generally unsuccessful due to the high rate of complications associated with implants in irradiated tissues. Fortunately, small volume fat grafts can sometimes be used to fill these areas. While it is very difficult to completely correct breast volume or shape, fat grafting can improve symmetry between the two breasts.
Megavolume fat grafting for full breast reconstruction?
Can fat grafting be used to reconstruct an entire breast? Recently, there has been growing interest in this question and methods for transferring large volumes, sometimes called megavolumes, of fat have been described. At the surface, this method has a great deal of appeal. It makes reconstructing the breast with natural tissues possible without the need for highly complex flap operations, such as the DIEP and GAP flaps, which transplant large pieces of intact tissue from other parts of the body.
A closer look at the details, however, reveals several intricacies associated with high volume fat grafting procedures. For example, many of the reports using these methods utilize machines to apply suction to the outside of the breast skin (external expansion). These devices have to be used for extended periods of time and can be quite laborious.
Furthermore, liposuction of very large volumes of fat tissue is needed to harvest the fat that is used for the breast reconstruction. Liposuction has its own associated potential complications which should be carefully considered when exploring reconstructive options:
- Contour deformities. If an area is aggressively over-suctioned, it can lead to divots in the skin. These can be very difficult to correct.
- Seromas. These are collections of body fluid in the areas that are suctioned. They can persist as soft contour deformities in the suctioned areas.
- Fat embolism. During liposuction, small blood vessels can be ruptured or broken, making it possible for small pieces of fat to enter the blood stream and plug vessels in the lungs and/or brain.
- Visceral perforation. Since liposuction is done through small puncture incisions, the surgeon cannot see the end of the liposuction cannula. This makes it possible for the tip of the cannula to travel deeper than desired, leading to puncture of the internal organs such as the intestines during abdominal liposuction.
Another potential concern that has been raised by some Medical Oncologists and Surgical Oncologists relates to the effects the grafted fat cells may have on the beds of tissue into which they are grafted. Fat tissue contains several different types of cells. Small parts of these cells are known as stem cells because they have the ability to turn into different types of tissue and to dictate the behavior of the cells nearby. For cases where the reconstruction is taking place after a mastectomy that is done for a breast cancer, this raises the theoretical concern that these stem cells, if grafted into the area where the cancer once was, could influence the behavior of the cells at the recipient site and promote cancer recurrences. Several scientific studies in laboratory and animal models have been carried out to evaluate this concern. Most show that the stem cells that are in fat grafts do not promote tumor growth, but some studies indicate otherwise and no human studies have been done at this time.
In summary, fat grafting is an important part of advanced breast reconstruction and can be used in several different ways to fine-tune other types of reconstruction and possibly even reconstruct entire breasts. While the technique has been around for years, there is a recent revival in interest around fat grafting and several centers are exploring the ways it can be safely used in breast reconstruction.
Dr. Kocak, MD, MS, of Midwest Breast and Aesthetic Surgery provides breast reconstruction, including perforator flaps, in Columbus and Cleveland, OH.