Extended TRAM flap: feasibility study on fresh human cadavers.

The purpose of this study was to investigate the feasibility of a superiorly based TRAM flap for breast reconstruction with its superior border abutting the inframammary fold. This flap would have a primary blood supply from the superior epigastric vessels, similar to a free flap attached to the mammary system. This flap, however, would not require microsurgery. Instead, it would have its superior epigastric pedicle lengthened by partial rib resection. Donor site closure would be accomplished by reverse abdominoplasty and the donor scar hidden in the inframammary fold. The surgical anatomy of such an extended TRAM flap (eTRAM) was investigated by cannulation of the internal mammary artery (IMA) in 10 fresh human cadavers bilaterally, injection with latex, and then dissection throughout its intrathoracic course. At the level of the third intercostal space, the mean external diameters of the right and left IMA were found to be 2.5 mm and 2.3 mm, respectively. The diameter of the vessel decreased until the IMA bifurcated into the superior epigastric artery and the musculophrenic artery, usually at the sixth intercostal space. The superior epigastric artery, having a mean diameter of 1.6 mm at its origin, descended caudally behind the seventh costal cartilage and could be followed until it entered the posterior rectus sheath and the rectus abdominis muscle. On its downward course, it was not embedded in the diaphragm muscle and was easily separated without violation of the thoracic cavity. From this anatomic study, it seems to be possible to raise an eTRAM after partial rib resection. Some technical considerations of such a flap are discussed. This modification of the TRAM would be helpful to surgeons commonly performing pedicled TRAM flaps and might extend its applicability beyond breast reconstruction to chest wall, intrathoracic, and head and neck reconstruction.