The cutaneous and subcutaneous layers are incised along the designated line using a blade or electric scalpel, for 20 cm, of which 5–7 cm lies caudal to the ASIS. The subcutaneous fat layer thickness depends on patient habitus (Fig. 11.2).
Fig. 11.2
Step 1: Cutaneous incision
11.4.2.2 Step 2
The external oblique muscle and its aponeurosis are exposed below the subcutaneous fat tissue, and a cuff featuring about 2 cm of the muscle is formed around the iliac crest for inclusion in the flap (Fig. 11.3).
Fig. 11.3
Step 2: Exposure of external oblique muscle
11.4.2.3 Step 3
The external oblique muscle is incised, preserving the cuff along the crest, and the muscle is then exposed. This elevation plane is quite avascular, and blunt dissection is easy (Fig. 11.4).
Fig. 11.4
Step 3: Incision and elevation of the external oblique muscle and exposure of the internal oblique muscle
Care must be taken when approaching the posterior part of the muscle, where the iliac crest naturally bends medially, to avoid excessive inclusion of the external oblique muscle in the flap. Frequent palpation of the iliac crest bone to ensure correct positioning is useful. The entire oblique internal muscle is exposed, and the amount of cuff needed for reconstruction is outlined (Fig. 11.5).
Fig. 11.5
Step 3: Complete exposure of the internal oblique muscle and delimitation of the muscle paddle of the flap
11.4.2.4 Step 4
The muscle is incised up to the transversus abdominis muscle following the designated line, beginning from the medial area (Fig. 11.6). The plane between the two muscles is not always easy to identify; it is usually most obvious near the last rib. The different directions of the muscle fibers are also helpful. Obviously, the attachment of the internal oblique muscle to the crest must not be interrupted.
Fig. 11.6
Step 4: Incision and elevation of the internal oblique muscle paddle
11.4.2.5 Step 5
The muscle is then elevated (in a medial-to-distal sequence) from the transversus, with careful cauterization of all intramuscular vessels (Fig. 11.7).
Fig. 11.7
Step 5: Complete elevation of the internal oblique muscle and exposure of the transversus muscle
During this maneuver, the ascending branch of the DCIA that supplies the muscle is identified in the ventral surface of the muscle (Fig. 11.8, arrow).
Fig. 11.8
Step 5: Identification of the ascending branch of the DCIA
11.4.2.6 Step 6
The ascending branch is followed distally during dissection until it enters the DCIA, enabling safe and reliable identification of the vascular pedicle of the flap (Fig. 11.9).
Fig. 11.9
Step 6: Identification of the flap pedicle
Once identified, the DCIA and DCIV are dissected from the surrounding tissue up to their junctions with the external iliac artery and vein, with care taken to ligate or coagulate vascular branches that are not to be included in the flap (Fig. 11.10).
Fig. 11.10
Step 6: Dissection of the vascular pedicle
11.4.2.7 Step 7
The transversus abdominis muscle is incised about 2 cm distal to the iliac crest (Fig. 11.11) to create a muscle cuff protecting the vascular pedicle (which should not be proximally exposed to the ASIS).
Fig. 11.11
Step 7: Incision of the transversus muscle
After incision of the transversus, the preperitoneal fat must be retracted to expose the iliacus muscle over the inner surface of the iliac bone (Fig. 11.12).
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