Attached TRAM flaps
Any tissue flap needs a healthy blood supply to survive when it is moved from the donor site up to the chest. In an attached or pedicled TRAM reconstruction, a flap of skin, fat and most of the underlying abdominis rectus muscle is separated from the abdomen and then tunneled under the skin and up to the mastectomy site. A single strip of muscle acts as an umbilical cord between the new breast and it’s original blood supply. This produces a good reconstruction with reliable blood supply, but recovery is intense, and the trade-off is the loss of one or both abdominal muscles. (One muscle is used to create a breast for unilateral reconstruction; both muscles are used for bilateral reconstruction.)
Free TRAM flaps
Free TRAM reconstruction was developed to preserve a part of the muscle; it uses the same tissue as the attached TRAM, but the flap, including a portion of the muscle that surrounds the blood supply, is transferred entirely from the abdomen to the mastectomy site, where the blood vessels in the flap are then reconnected to blood vessels in the chest. This eliminates the need to tunnel under the skin (and the bulges that may develop) and reduces the likelihood of hernia. There’s a downside with Free TRAM as well, however: although the muscle remains in the abdomen, it is cut across its width to remove the small portion that is included in the flap. So even though most of the muscle remains in place, much of the muscle functionality is destroyed.
Muscle-sparing DIEP and SIEA flaps
The premise behind DIEP and SIEA flaps is simple: recreating breasts with living tissue without sacrificing any muscle. Deep inferior epigastric perforator (DIEP) flaps and superficial inferior epigastric artery (SIEA) flaps are improvements on tummy tuck flaps that are used for reconstruction. Unlike attached and free TRAMs, these DIEP and SIEA flaps leave the entire abdominis rectus muscle intact. The surgeries do require advanced skills to carefully extract the blood vessels from the muscle, and the operation takes longer, but the result is the same soft reconstructed breast with shorter recovery and no loss of muscle functionality in the abdomen.
DIEP and SIEA are essentially the same technique. The only difference is the source of blood vessels feeding the flap. Whichever artery provides the dominant supply of blood to the abdomen is used. The SIEA is advantageous because it runs just under the skin and doesn’t require cutting into the muscle at all; recovery is improved because the abdominal muscle is not only spared but is left undisturbed. In most women, however, the SIEA is usually too small to support the breast flap or has previously been severed during hysterectomy or cesarean surgery.
Attached TRAM was developed based on surgical abilities and restrictions more than 30 years ago, before techniques to tease delicate blood vessels from within the muscle made DIEP/SIEA possible. Even so, the attached TRAM is still widely performed, primarily because it is more available than DIEP/SIEA.
Looking at a reconstructed breast, you wouldn’t be able to identify which was created with a TRAM, DIEP or SIEA flap. Each of these procedures produces soft, natural-looking breasts. Nor would the abdominal incision site provide a clue: each of the surgeries leave a hip-to-hip scar between the belly button and the pubic bone.
Easier recovery and no loss of muscle make DIEP and SIEA advantageous for most women, but there are reasons why a lot of women have TRAMs instead. TRAM has been around a lot longer than DIEP/SIEA, and doesn’t require advanced microsurgical skills, so more surgeons perform TRAM. In some cases, health insurers still insist that DIEP/SIEA is experimental, even though they have been performed for several years. Some women never realize that DIEP/SIEA i even an option. For others, the need to travel to a DIEP/SIEA surgeon may be more than they are willing to do.
The good news is that more and more reconstructive surgeons are learning to perform DIEP/SIEA (and more health insurers are recognizing DIEP/SIEA as reconstructive options, making it more likely that women have the opportunity for muscle-sparing abdominal flaps for their breast reconstruction.