Circulating Mechanism of the “Pure” Venous Flap: Direct Observation of Microcirculation

ABSTRACT

The circulating mechanism of the “pure” venous flap was studied via venography and direct observation of the microcirculation through transparent ear chambers and ear edges in a rabbit model. The flap, without arterial inflow, survived with normal hair growth and wound healing. Renewed blood circulation occurred 3 to 5 hr after transfer. There were two typical flow patterns in the venules: one was a shaking movement with high frequency and short range; the other was a pendulum-like movement with low frequency and long range. The former was related to heart rate, while the later was not. The pendulum-like movement was the main flow responsible for perfusion of capillaries. Blood flow in the capillaries occurred 1 to 2 hr later than that in the venules. The pendulum-like flow perfused the capillaries in two ways: one was in the direction of venules to capillaries and then back to venules along the same route; the other was from venules to arterioles through arteriovenous shunts and then to capillaries. The first type of perfusion was gradually replaced by the second 2 days after transfer. There were extensive venous plexus flows in the flap, which lasted more than 4 weeks after transfer. Revascularized vessels ultimately supplied blood to the flap. The dynamic energy for the movement of blood at an early post-transfer stage was probably due to spontaneous venomotion.