[An experimental study to determine the most effective delay procedures on secondary vascularized skin island flaps].

Secondary vascularized flaps made from implanted vascular bundles in the subcutaneous tissues have dominant vascularities. Animal experiments were performed using white rabbits, two types of skin flaps were made on their backs. The first delay procedure was performed on the left side where the vascular bundle had been implanted with an elevation of distally based flap (size 2 cm x 7 cm). 28 out of 32, secondary vascularized skin island flaps survived either partially or completely in the first procedure. Moreover, the first delay method was observed to be efficacious in 15 out of 16 cases (p less than 0.01). The viability of vascular bundles of secondary vascularized flap was thus proved. The first stage of the second delay procedure was performed in bilateral side using the same procedure as the first delay. Two weeks later, two types of delay method were carried out. On the left side, a proximally based flap (size 2 cm x 7 cm) was made at the distal area of the first delay flap. On the right side, a bipedicled flap was made (size 2 cm x 14 cm). These flaps were elevated as secondary vascularized skin island flaps two weeks later. In all cases, the latter procedure produced a longer survival rate compared with the former (p less than 0.01). It was concluded experimentally that the most effective second delay procedure was the bipedicled flap method.