Comparison of two types of arterialized venous forearm flaps for oral reconstruction and proposal of a reliable procedure.

The mechanism of survival of venous flaps is not yet completely understood. To determine the conditions for reliable success, in 1996 and 1997 we used arterialized venous forearm flaps for oral reconstruction in patients with neoplastic disease. Building on earlier experience with flow-through flaps, we compared two different designs obeying the following specifications: five so-called arterialized flow-through flaps, elevated from the ulnar flexor side of the forearm, with a single vein for orthograde inflow and outflow, diameter not larger than 2 mm (type 1); and five arterialized flaps with two parallel veins on the proximal side of the flap, also with a diameter of 1-2 mm, to avoid by-passing of flap tissue by 'catching' the blood in the venous/capillary system (type 2). There were nine male and one female patients with a mean age of 55.7 years. We covered defects of the anterior or anterolateral floor of the mouth to avoid folding of the flaps. Microsurgical anastomosis was done to the facial artery, the cranial thyroid artery and the external jugular vein or the facial vein. Average size of the flaps was 23 +/- 7.28 cm2 (type 1) and 25 +/- 5 cm2 (type 2). Four flaps of type 1 showed total or subtotal success and only one was lost because of a haematoma. In comparison with this we saw three losses in type 2 and only one partial and one total success, respectively. Analysis showed regularly occurring problems: there was failure of venous drainage in the lost type 2 flaps one day after microsurgery. In the flow-through flaps and the surviving type 2 flaps which had visible communicating branches between the two veins, the partial by-passing of the arterial input avoided this problem. There was no donor site morbidity after covering with a split-thickness skin graft. It could be shown that survival of arterialized venous forearm flaps is based on a combination of an arteriovenous shunt and capillary blood flow. In conclusion, we define six rules for a reliable venous forearm flap.