The surgeon is occasionally confronted with a large defect which requires reconstruction without delay, which will not accept a free skin graft, and for which, for technical reasons, no flap is suitable, whether skin, fasciocutaneous, muscle or myocutaneous, pedicled or free. The sites most likely to give rise to such a problem are the scalp and the anterior chest wall.
In the scalp area, the form the problem takes is how to provide cover as rapidly as possible for the defect with an extensive area of bare bone on the vault of the skull, and prevent it from progressing to sequestration of the outer table. In the chest wall, the problem concerns the extensive defect, usually from a combination of breast surgery and radiation, which is clearly incapable of granulating.
A possible solution in both situations may
be to cover the defect with a tissue which will produce granulations rapidly and effectively,
and provide a surface which will then accept a free skin graft. The omentum is such a tissue , and it has the additional virtue of being able to fill a dead space with extremely vascular tissue, of particular value when the space is chronically infected, or the result of radiation injury.
In preparing the omentum for transfer,
it is first freed from its avascular attachments to the transverse colon, leaving it attached along the greater curvature of the stomach. It is vascularised from branches of the epiploic vessels which form a series of loops in the direction of its free border.
For transfer as a pedicled flap, it is usually pedicled on the right gastro-epiploic vessels, the larger of the two, though either can be used, the branches to the stomach being divided to allow it to be mobilised. Its looped vascular pattern allows it to be lengthened without losing its vascula-rity, and the calibre of its vessels makes its transfer as a free flap technically straight-forward.
Used as a free flap, omentum can be transferred
to the scalp area, using the superficial temporal vessels for anastomosis.
Used as a pedicled flap, it can be used to cover
the anterior chest wall. It is harvested using a linea alba approach, leaving a gap in its upper end to allow its transfer.
Depending on the degree of adiposity of the
patient the omentum can either be a substantial structure containing a proportion of fat, or apparently insubstantial. Regardless of which form it takes, when spread over the defect and tacked to its margins, it produces granulations with remarkable speed, and accepts a split skin graft readily.
The use of omentum has obvious disadvan-
tages, with the need for a laparotomy, and the postoperative discomfort and degree of immobility of the patient which is inevitable. The amount of tissue the omentum can provide cannot be assessed preoperatively, nor can the effect on it of previous abdominal surgery. It is generally used only when every alternative has been considered and none has been found suitable.
In such a situation its ad-verse features have to be accepted.