**3.1 Applied anatomy**

Rectus abdominis is a *vertically oriented* flat muscle *situated on* the bilateral side of the midline of the abdomen and en-sheathed into the anterior and posterior rectus sheath. It *arises* from the costochondral parts of the 5th, 6th, and 7th ribs and xiphisternum and is *inserted* into pubic symphysis. It has two dominant vascular pedicles, thus making it a kind of *type III* muscle. Superiorly it is *nourished by* the superior epigastric artery and veins that arise from internal mammary arteries and veins respectively and inferiorly it is supplied by the deep inferior epigastric artery and veins which is a branch of the external iliac artery and accompanying veins respectively. It is also supplied by several minor pedicles of subcostal and intercostal arteries and veins.

Based on the arterial and venous circulation pattern, the lower abdomen is divided into four zones (I–IV) of perfusion. *Zone I* is just above the muscle on the ipsilateral side, and *Zone II* is the zone opposite to the muscle on the contralateral side. *Zone III* is the ipsilateral side adjacent to Zone I and *Zone IV* is the contralateral side adjacent to Zone II.

The anterior rectus sheath overlies the rectus abdominis muscle and the anterior rectus sheath contains three tendinous intersections, first at the level of costal cartilage, second at the midpoint between the umbilicus and costal cartilage, and third at the level of umbilicus.

## **3.2 Flap harvesting**

*Flap marking***: (Figure 6)** The flap's skin paddle can be marked *vertically* along the muscle or *transversely* in the lower abdomen. In the case of women with pannus who desire to undergo abdominoplasty surgery, the flap is marked in the same fashion as an abdominoplasty incision. Lower abdominal tissue is pinched with the thumb and index finger and that determines the donor area to be closed primarily. The both sides of ASIS (Anterior superior iliac spine) are marked, then an incision is marked joining the two ASIS meeting in the midline just above the mons pubis. Another curvilinear incision is marked superiorly so the skin paddle of the flap becomes boat-shaped or elliptical. Both sides of muscles are marked along with two subcostal sides. The umbilicus is marked circumferentially for dissection. It is also important to examine the presence of rectus diastasis (straight leg raising test) which is marked accordingly.

*Technique*: An incision is made first in the lower part, and skin and subcutaneous tissue are incised. If possible, an attempt may be made to dissect the superficial inferior epigastric veins which will be in the subcutaneous space of the lower abdomen on

**Figure 6.** *Marking for TRAM flap.*

#### *Flaps for Breast Reconstruction DOI: http://dx.doi.org/10.5772/intechopen.114019*

both sides. The same vein can be used for supercharging in case of venous congestion of superiorly based pedicle flap or as an extra draining vein for free flap. The superior incision is made and the elliptical flap is elevated from lateral to medial. Once we reach near the lateral border of the anterior rectus sheath, we get the lateral row of perforators, that is cauterized and sacrificed. Anterior rectus sheath is incised and a plane is dissected between the rectus muscle anteriorly and posteriorly, away from the skin paddle. It is important to maintain the continuity of the rectus sheath anteriorly with the skin paddle and muscles. Also, the tendinous intersection found at three defined levels needs to be dissected. In case of *superiorly based pedicle flap*, the superior pedicle is dissected which lies in the subcostal region deep to muscle in its medial half. The muscle including soft tissue is dissected from below upwards and is brought over the defects for insetting. A tunnel is created between the defect and the origin the of muscle (**Figure 7**). The inset is completed.

For raising it as a free flap for breast reconstruction, it can be as VRAM or TRAM. The commonly performed TRAM has its pedicle in the lower part, once we elevate the muscle, it is easier to identify the pedicle which is dissected to its origins. It is usually found lateral half of the muscle in the lower parts. The muscle is cut superiorly and the flap includes skin and a subcutaneous tissue along with muscle. We can reconstruct the breast by providing the good bulk of muscle by either pedicle or free rectus abdominis myocutenous flap (**Figure 8**).

*The donor area*: The donor area is closed primarily in layers after securing the hemostasis. If there is a presence of rectus diastasis, rectus plication can be done. Also, any hernial orifices can be reduced and repaired in the same sitting by putting mesh. It can be combined with the dissection of upper abdominal tissue along with the repositioning of the umbilicus.

**Figure 7.** *TRAM flap dissected with the creation of tunnel through mastectomy side.*

#### **Figure 8.**

*Late post-operative result of TRAM flap reconstruction.*
