An experimental neurovascular island skin flap for the study of the delay phenomenon.

We present an experimental neurovascular island skin flap. It is a consistent, reproducible model which produces a definite pattern of surviving skin flap area versus skin flap necrosis. There is a constant, anatomically definable nerve and vascular supply to the flap. This model permits independent experimental manipulation of the neural, arterial, and venous supply to the skin. It is useful, therefore, for the study of the vascular mechanisms of the skin microcirculation. We also demonstrated that increased flap survival can be produced by a delay involving denervation alone (leaving the vascular supply intact) or by devascularization alone (leaving the nerve supply intact). We conclude that both the adrenergic denervation and the ischemia contribute to the production of the delay phenomenon. We suggest that sustained vasodilation--vascular smooth muscle relaxation--is the vascular mechanism that accounts for the delay phenomenon.