The anatomic basis for arteriovenous shunting in human lower leg fascial flaps

Clinical experience has suggested that arteriovenous shunting may occur in fascial flaps. The anatomic basis for this has not been fully established. The aim of this study was to determine the size, location, and nature of arteriovenous shunts in human lower leg deep fascia. Deep fascia was harvested from the limbs of nine embalmed cadavers. Small pieces of fascial tissue were studied with the aid of three staining techniques (methylene blue, oil red-O triethyl phosphate, and Gomori's rapid one-stage trichrome technique), which were used to enable the microvascular anatomy to be visualized more clearly. Arteriovenous anastomoses proximal to the capillary bed and with an external diameter greater than 50 microns were identified in the suprafascial, subfascial, and intrafascial plexuses but were not found to be a common feature of the microvascular anatomy. Thoroughfare channels within the capillary bed and with an external diameter ranging from 12 to 25 microns were frequently identified in all three levels of the fascial plexus. The results of this study establish an anatomic basis for arteriovenous shunting in fascial flaps.