the purpose of this experimental model with rabbits is investigating the variation of blood flow in the expanded skin versus expansion time. new zealand breed rabbits are used. two groups are studied: f-1 receiving expanders on the right tight and f-2 receiving expanders bilateraly. progressively, five expansions are performed. the first radioiosotopic perfusional evaluation is performed just after the surgery and the following evaluation are performed at the second, sixth, thirteenth, twentieth and twenty-seventh post-surgical days. as radiotracer, technetium 99m are used in the chemical form of sodium pertechnetate. scintillographic images are obtained by cgr scintillation camera. the quantitative analysis is done by calculation of the reperfusion rate.