Prefabricated flap size limitations utilizing an omental carrier.

Several researchers and clinicians have taken advantage of the omentum's rich vascular arcades to support skin grafts. We have previously described an experimental model using the omentum as a vascular carrier for prefabricated free flaps in the rat. In this study, we used this model to compare three different sizes of free flaps using the same size omental carrier. Twenty-four male Sprague-Dawley rats were used for this study. A 2.5 x 4 cm patch of omentum with gastroepiploic vessels and its rich vascular arcades was transferred under a bipedicled 2.5 x 6 cm (group I), a 2.5 x 8 cm (group II), and a 4 x 10 cm (group III) right abdominal panniculocutaneous flap. On the seventh postoperative day, the skin pedicles were divided and the skin flap raised as a composite island flap vascularized only by the underlying omental patch. The composite flap was then sutured back in place. Prefabricated flaps examined 7 days postoperatively demonstrated a dye florescence index percent (DFI) of 38.19 +/- 7.52 and 98.13 +/- 3.72% flap survival (FS) in the 6 x 2.5 cm skin flap group; a DFI of 39.96 +/- 6.81% and FS 94.88 +/- 7.08% in the 8 x 2.5 skin flap group (P > 0.05) and a DFI 29.71 +/- 2.85% and FS 57.06 +/- 9.52% in the 10 x 4 cm skin flap group (P < 0.05). India ink injection study and histologic examination confirmed revascularization of the overlying skin at 7 days. This study confirms that omentum can be used as a vascular carrier for prefabricated flaps. However, there is a limit to the size of the flap. A 10 cm2 carrier can support 57% of a 40 cm2 (10 x 4 cm) flap for a total area of 22.8 cm2, more than twice the area of the carrier.