Thoracoabdominal Flaps for Breast Reconstruction: Different Types and Classification

*Ernesto A. Moretti*

## **Abstract**

The thoracoabdominal flaps allow the closure thoracic defects with a lower technical difficulty and morbidity compared to remote flaps. In mammary oncological reconstructive surgery, they were used primarily as fasciocutaneous flaps for patients with locally advanced breast cancer (T3 and T4 tumors) that require large skin resections and a fast and effective coverage of the thoracic defect. In recent years, they have resurged as a therapeutic option to solve postoperative complications due to ischemia and skin necrosis with exposure of tissue expanders or breast implants. The increase in the practice of risk-reducing mastectomies (RRM) has led to areas of small skin suffering or necrosis that require local flaps to solve the complication. It is in these indications, where these flaps have an optimal application. In the present study, the thoracoabdominal flaps are presented as a very useful reconstructive technique to cover skin defects in breast surgery complications. A classification is presented to clarify these fasciocutaneous flaps, as well as examples of their applications.

**Keywords:** thoracoabdominal flap, thoracoepigastric flap, breast reconstruction, surgery, complications

#### **1. Introduction**

The reconstruction of breast deformities secondary to procedures for oncological disease is still one of the main challenges of reconstructive plastic surgery. Immediate reconstruction with alloplastic materials is one of the most common alternatives for selected patients, who often prefer this type of surgery over reconstruction with more extensive and complex procedures that involve the use of autologous tissues [1]. However, the resection techniques and the adjuvant treatments for oncological surgery condition (particularly radiotherapy) frequently give a hostile and inadequate adaptation of the organism to implants and tissue expanders, producing in numerous cases the dehiscence of wounds, necrosis of the cutaneous tissues, and the exposure of the alloplastic material, risking the esthetic result of the surgery, and on unfortunate occasions, lead to the failure of the repair technique due to the need for explantation, producing a transient deformity that has a high emotional impact for the patient [2].

The thoracoabdominal flaps are one of the best known and most used flaps in breast reconstruction surgery, particularly in resolving complications.

This chapter details the thoracoabdominal flaps described in the literature, as well as clarifies their planning and rotation. A classification is presented to avoid confusion in the nomenclature.

## **2. History**

The lateral pedicle thoracoabdominal flap or also called the lateral thoracodorsal flap is a rotation/transposition fasciocutaneous flap based on the posterior perforators of the intercostal vessels of the thoracodorsal vessels and was initially described by Hölmstrom and Lossing [3] in 1986. In their publication, the flap is combined with breast implants as an alternative to musculocutaneous flaps for breast reconstruction. The Hölmstrom technique is based on the description of the thoracoepigastric flap described by Cronin [4] and Bohmert [5], a technique that describes a similar flap but with a medial pedicle (based on the perforators of the superior epigastric artery).

The use of this lateral pedicle thoracoabdominal flap has had numerous publications in Scandinavian countries, where there are several publications [6–8]. In Latin America, although is less widespread, there are works published such as Pontes [9] from Brazil, Carriquiri [10] from Uruguay, and Fullana Sastre from Barcelona [11].

## **3. Anatomy of the toracoabdominal flaps**

When considering the anatomy of the intercostal vessels, it is important to understand its origins. The intercostal vessels form an arcade between the aorta posteriorly and the internal mammary vessels anteriorly.

The arcade is divided into vertebral, costal, and muscular segments. In the lateral area of the thorax, the six, seven, and eight intercostal vessels give lateral anterior perforators (LICAP: lateral intercostal anterior perforator) that provide irrigation to the skin, subcutaneous tissues, and muscular fascias (**Figure 1**).

These perforators supply the anterior region of the thorax and abdomen below the lower outer quadrant (LOQ) of the mammary region. The intercostal vessels continue their internal course below the costal arches and deliver the second anterior perforators. This perforator is called AICAP (anterior intercostal perforator), which supplies the regions of the thorax and abdomen at the level of the lower inner quadrant (LIQ) of the mammary region (**Figure 2**).

These perforators of the intercostal vessels six, seven, and eight can be identified with echo Doppler, although they can constantly be marked in an imaginary vertical line from the submammary fold to the nipple-areola complex. Continuing along the route, the intercostal vessels join to the internal mammary or middle thoracic artery, closing the vascular circuit (**Figure 3**). This artery is a collateral vessel from the subclavian artery.

In this thoracoabdominal area below the lower internal quadrant of the breast, the middle thoracic artery delivers perforators at the level of the sixth costal arch and subsequently delivers perforators that cross the rectus abdominis muscle. In this area, the internal mammary artery changes name to the superior epigastric artery. These perforators supply the central part and lower inner quadrants of the thoracic region and upper hemiabdomen, making the MICAP perforators (Middle Intercostal Anterior Perforator) (**Figure 4**).

*Thoracoabdominal Flaps for Breast Reconstruction: Different Types and Classification DOI: http://dx.doi.org/10.5772/intechopen.112912*

#### **Figure 1.**

*Intraoperative image at the level of the submammary fold in its external area, where the lateral perforator of the intercostal vessels (LICAP) is marked (red arrow).*

#### **Figure 2.**

*Intraoperative image of breast reduction surgery, where the anterior perforating vessels of the fifth intercostal artery are observed (AICAP).*

#### **Figure 3.**

*Image obtained from fresh cadaveric dissection, where the second, third, fourth, and fifth intercostal arteries are observed in the direction of joining with the internal mammary artery. The red arrows show the perforators.*

#### **Figure 4.**

*Image where the first perforator of the superior epigastric artery is identified with a red arrow. This perforator comes from the internal mammary artery that changes its name when it crosses the diaphragm. The perforator of the sixth intercostal artery provides irrigation to the innermost sectors of the lower region of the thorax (MICAP) (yellow arrow). Anatomically, the perforators of the epigastric artery do not join the intercostal vessels.*

*Thoracoabdominal Flaps for Breast Reconstruction: Different Types and Classification DOI: http://dx.doi.org/10.5772/intechopen.112912*

#### **Figure 5.**

*Intraoperative image of breast reconstruction showing the lateral thoracic artery perforator, base of the fasciocutaneous flap LTAP.*

It should also be mentioned that the lateral irrigation of the thorax and upper hemiabdomen receive irrigation from the lateral thoracic artery, which comes from the axillary artery, and delivers two to three perforators in its lower part, creating perforators called LTAP (lateral thoracic artery perforator) (**Figure 5**). These perforators supply the skin, subcutaneous tissue, and muscle fascia at the level of the midaxillary line in the region of the sixth, seventh, and eighth ribs.

In conclusion, the area of the chest wall beneath the inframammary fold and upper abdominal area can be divided into four regions. Medially, the medial intercostal artery perforator (MICAP) is present; centrally, the AICAP is present, and laterally, the LICAP and the LTAP are present.

#### **4. Surgical variants**

The following table classifies the fasciocutaneous flaps of the upper hemiabdomen and lower parts of the thorax. Different thoracoabdominal flaps and their surgical variants are listed.

## **5. Classification**

#### **5.1 Fasciocutaneous flaps of the upper hemiabdomen and lower part of the thorax**

• TYPE I: Lateral Thoracoabdominal Flaps.

	- III A: Lateral rotation base (based on the LICAP).
	- III B: Medial rotation base (based on the MICAP).
	- IV A: Lateral rotation base (based on the LICAP).
	- IV B: Medial rotation base (based on the MICAP).
