An experimental study of prefabricated flaps using silicone sheets, with reference to the vascular patternization process.

A study of the vascularization process in prefabricated flaps, using silicone sheets, has been undertaken in rat models. It was found that the survival rate of flaps was most stable from 2 to 3 weeks after insertion of the silicone sheet, and that this rate decreased when the silicone sheet remained in place beyond that period. The results are probably due to the decrease of delayed effect. Changes that occurred in the circulation and component blood vessels within the flap over time were studied by microangiography, and were categorized at the following four stages: at less than 1 week from the initial surgery, from 1 week but less than 2 weeks, from 2 weeks but less than 4 weeks, and 4 weeks or more. The component vessels consisted of three types, that is, transferred vessels, original vessels, and newly formed vessels, with the last type further divided into three subtypes, to clarify the timing of the vascular proliferation and dilatation for each of the component vessels.