The superficial inferior epigastric artery flap (SIEA) reconstruction is performed with soft tissue from the abdomen including skin and fat, but does not require any dissection of muscle in the abdominal wall. In theory, this flap should be even less prone to hernia formation than the DIEP, but we have seen very little evidence of hernia formation even after DIEP flap harvest. The main advantage of the SIEA flap is that less dissection results in less postoperative pain and quicker recovery from surgery.
It is interesting to note that the SIEA flap has been performed almost since the inception of microsurgery and was actually described in the mid 1970's. In fact, it was used at that time for breast reconstruction but the flap fell out of favor because it was felt to be technically quite difficult (it is and was more so then). With advances in reconstructive techniques, we are now able to reapply this flap for breast reconstruction.
This SIEA can be used for immediate or delayed breast reconstruction. It consists of the abdominal skin and fat and some blood vessels. The tissue gets nourishing circulation from superficial vessels just below the skin surface. Like the DIEP flap, the tissue that is used is the same tissue that is discarded in the cosmetic tummy tuck operation: more commonly known as an abdominoplasty.
The SIEA flap is technically more demanding than the DIEP flap because of the small blood vessel size, and should only be performed by experienced microsurgeons and microsurgical teams. Whether the SIEA flap or DIEP flap can be used for reconstruction depends on intraoperative findings related to vessel size and blood flow. The decision between DIEP or SIEA is usually an intraoperative decision based on blood supply.
Not all patients have the SIEA blood vessels or adequate vessel size. The absence, presence or adequacy of vessels cannot be determined for certainly until after surgery begins, although a non-invasive Doppler exam can be helpful in predicting vessel presence. Patients who have had Cesarean sections are less likely to have SIEA vessels. If SIEA vessels are not present, patients are reconstructed with the DIEP flap.Although we like to perform the SIEA reconstruction if we can, since it provides an opportunity for less surgical dissection, the DIEP flap is excellent as well. Rather than calling it a second choice, we like to think of it as an equally good alternate to the SIEA.
Another point to remember is that if a patient requires a particularly large reconstruction that requires more than half of the abdominal skin and fat, then she may not be able to have an SIEA flap even if vessels are present. This is because the SIEA flap sometimes does not provide adequate circulation across the midline of the abdomen. If that is the case, the DIEP flap is used.
The figure above the same abdominal tissue (outlined in blue) that is used in the DIEP flap is used in the SIEA reconstruction. After this tissue is used for the reconstruction, the abdominal procedure is completed with a tummy tuck.
Advantages of the SIEA flap include:
The SIEA flap can be used for immediate or delayed breast reconstruction.
The tissue used for SIEA breast reconstruction contains skin, fat and blood vessels. It is the same tissue area that is discarded in the classical cosmetic surgery procedure called the tummy tuck. The technical name for the cosmetic procedure is abdominoplasty. In reconstructive breast surgery, instead of discarding the abdominal tummy tuck tissue, the tissue is used to reconstruct a breast.
The area outlined in blue on the abdomen represents the amount of abdominal skin that typically is removed in SIEA reconstruction. The paired rectus abdominus muscles are illustrated in dark red. They are the muscles that give the abdomen strength and are the major generators of force in the sit-up. Their outlines are seen in physically fit individuals as a "six pack".
The blood vessels are pictured that supply circulation to the abdominal tissue. These vessels are superficial to the muscles and run in the substance of the abdominal fat. In a TRAM flap, the muscle is cut and used as part of the reconstruction. This creates potential for abdominal weakness and hernias. In the SIEA flap the muscle is not removed. A major advantage of the SIEA flap is that it does not require loss of the rectus abdominus muscles.
In microvascular SIEA breast reconstruction, the excess abdominal skin and fat is removed, without any need for removal of abdominal muscles or the supporting fascia. Shaping of the fat and skin is performed to match as closely as possible to the other breast.
A small piece of rib cartilage is removed from the chest and the blood vessels underneath the cartilage are used to establish cirulation in the shaped abdominal fat and skin. In some patients, no rib cartilage is removed.