Anatomical landmark identification and patient positioning
10.3.2 Flap Design
The main surgical landmarks are the scapula especially the tip and the lateral board, the anterior superior iliac spine, and finally the midaxillary line. The first step is to draw a line which connects the midpoint of the axilla and a point midway between the anterior superior iliac spine and the posterior superior iliac spine on the iliac crest. This line corresponds to the latissimus dorsi line. Further steps depend on the type of flap required for the reconstruction. Skin paddles may be drawn on the skin depending on the surgical plan; multiple skin paddles can be harvested on the latissimus dorsi, anterior serratus, and scapular and parascapular flaps (Fig. 10.2a). Latissimus dorsi skin flap is drawn at the proximal or middle third of the line, because in this area perforating vessels that supply the skin are more numerous and reliable (Fig. 10.2a, b).
Fig. 10.2
Anatomical landmark identification with lat dorsi flap
When no skin paddle is needed, incision line is draw from midpoint of axilla and midpoint between anterior superior iliac spine and posterior superior iliac spine on the iliac crest (Fig. 10.3).
Fig. 10.3
Anatomical landmark identification without skin paddle
10.3.3 Step 1: Skin Incision
The skin incision and the flap design depend on the type of flap that will be harvested. In case of latissimus dorsi component, the incision is performed along the anterior margin of latissimus dorsi flap. The upper part of the incision can be S shape for a less tension closure at the end of flap harvesting. When it is not necessary, the incision follows the line previously outlined. The depth of the incision reaches the latissimus dorsi muscle and its fascia (Fig. 10.4).
Fig. 10.4
Step 1: Skin incision
In the downward part, the latissimus dorsi muscle fibers and the serratus anterior muscle fibers are positioned almost perpendicular (Fig. 10.5, red arrow). The first is on a deeper plane than the latter. The skin and subcutaneous tissue located at the superior boarder should be anchored with some hooks or skin stitches.
Fig. 10.5
Step 1: anterior skin flap elevation; lat dorsi and anterior serratus muscles identification
10.3.4 Step 2: Identification of Subscapular Vascular System
The connective tissue between latissimus dorsi and anterior serratus muscle contains the subscapular vascular system and its branches. The dissection of this space must be performed accurately, to allow the identification of all parts of the vascular system. The artery that supplies the anterior serratus muscle usually is the first to be visible. It goes along the muscle in contact to it (Fig. 10.6 red arrow). Artery that feeds the latissimus dorsi muscle normally starts in the posterior portion of the pedicle entering the muscle in its proximal third.
Fig. 10.6
Step 2: identification of anterior serratus branch of the pedicle (red arrow)
These two arteries are normally the terminal ones. The surgeon, usually, follows one of these braches to reach thoracodorsal trunk. Subsequently, it is possible to identify the other branches, the angular artery and the circumflex artery (Fig. 10.7).
Fig. 10.7
Step 2: main pedicle is identify
The circumflex artery is shown in Fig. 10.8 (yellow arrow). This artery is normally the first branch of thoracodorsal artery that origins from the axillary artery (red arrow) located near its vein (blue arrow).
Fig. 10.8
Step 2: anatomy of the subscapular system is shown: circumflex artery (yellow arrow); axillary vein (blue arrow) and artery (red arrow)
The angular artery starts normally deeper than the other ones, but there is a great variability in its origin. For this reason, it is more difficult to identify it.
Figure 10.9 shows the subscapular vascular system (green arrow, anterior serratus artery; yellow arrow, angular artery; blue arrow, latissimus dorsi artery; violet arrow, circumflex artery; and red arrow, subscapular artery).
Fig. 10.9
Step 2: Subscapular vascular system
The subsequent steps are based on the type of flap that is necessary.
10.3.5 Step 3: Latissimus Dorsi Flap Harvesting
When the vascular pedicle of the latissimus dorsi is identified (Fig. 10.10 red arrows, Fig. 10.11 right arrow), the projection of the artery is sign on the skin. A more precise skin flap is designed, depending on the surgical defect. Skin island dimensions can be up to 20 cm width (maximum to close primarily 8–10 cm), and 30 cm length in dimension can be harvested (Fig. 10.10).
Fig. 10.10
Step 3: latissimus dorsi flap harvesting
Fig. 10.11
Step 3: latissimus dorsi pedicle
At this time, posterior skin incision and resection of the muscle from downward to upward are performed. Keep in mind the position of the angular artery (Fig. 10.12 yellow arrow) and the latissimus dorsi one.
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