Omental Transposition
In this procedure, the transverse colon and stomach are delivered out of the abdomen. The greater omentum is then detached from the transverse colon. The omental apron is lifted upward, and the lesser sac is approached via the posterior part of the greater omentum. Dissection is carried out in the avascular plane between the antimesenteric border of the transverse colon and the posterior layer of the greater omentum.
The arterial pattern of the omental vessels (see the image below) is carefully studied. It is of particular importance to note the sizes of the right and left gastroepiploic arteries. Either of these vessels may be selected as a feeding vessel on which a pedicled graft is to be constructed.
The greater omentum is then detached from the greater curvature of thw stomach. The gastroepiploic arterial arch is retained in the omental pedicle graft. The vessels between the stomach and the arch are individually ligated and carefully divided. Strict hemostasis is maintained throughout. The omental pedicle must not be subjected to tension and must be kept moist during the procedure.
Once the omentum has been fully mobilized, the clinician should make the decision regarding which gastroepiploic artery should be divided in the creation of the omental pedicle. The omentum is then lengthened by dividing it according to the anatomic pattern of the vessels. The omental pedicle is converted into a ribbon form in this fashion. The distal end is tied with a thread to facilitate tunneling down the lower limbs. Again, strict hemostasis should be maintained throughout this procedure.
A suprainguinal incision about 3-4 cm in length is made on the affected side, and the omental pedicle is withdrawn from the abdomen, with care taken to ensure that it is not twisted or subjected to tension. Arterial pulsation should be readily palpable. The abdomen is closed in layers.
A horizontal subcutaneous incision about 4 cm in length is then made over the upper third of the thigh. Between this upper-thigh incision and the previously placed suprainguinal incision, a subcutaneous tunnel is made with the help of blunt dissection and an arterial forceps. The omental pedicle is advanced through this tunnel and brought out through the lower incision.
The omental pedicle is then placed over the leg, and its length is marked on the skin of the limb (see the first image below). A series of transverse incisions (typically three or four) are made over the medial aspect of the thigh and leg (see the second image below). The clinician should make a subfascial tunnel connecting these incisions, and the omental pedicle is advanced along this tunnel and delivered out of the last incision. The thread marker is removed, and the distal end of the pedicle is fixed to the gastrocnemius with atraumatic 2-0 chromic catgut.
The final step of the procedure is surgical wound closure. In the suprainguinal incision, the peritoneum is closed at the lateral ends so that the pedicle is not constricted. At all of the incision sites, the skin is sutured with nonabsorbable suture material; care must be taken not to include the omentum. After all of the wounds have been cleaned with an antiseptic solution, sterile dressings are applied.
Complications
Complications of pedicled omentoplasty include the following:
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Ileus
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Infection
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Abscess formation
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Intestinal obstruction
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Total necrosis of the omental flap
Performance of a pedicled omentoplasty with special attention to transposing techniques may minimize the complications attached to it.
One unusual complication involves herniation occurring through the tunnel created to bring the omentum into the thigh. Boiskin et al observed herniation of the transverse colon into the transposed omentum that was used for chest reconstruction after sternectomy. [26]
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Omentoplasty. Omentum being mobilized.
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Omentoplasty. Omentum being mobilized to reach below knee.
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Omentoplasty. Skin incisions made on limb for subcutaneous tunneling of omentum.
