Free flap neovascularization: myth or reality?

The blood supply of 17 free flaps was studied several months after surgery. The aim was to see whether or not the free flaps acquired blood flow through vessels across the flap inset independently of the main vascular anastomoses. A color Doppler flowmeter was used to identify the original arterial and venous anastomoses, the vessels in the margin of the flap, and also across the flap inset. The main vascular pedicle was then manually compressed for 2 min and blood flow was again examined in the vessels at the margin of the flap. The flap vessels (post-anastomotic), the anastomoses, and the recipient vessels (pre-anastomotic) could be identified in every case. There was no evidence of anastomotic stenosis. No vessels (neo-vascularization) greater than 0.5 mm could be identified across the flap inset. Small arteries could be identified in the flap near the inset. These vessels emptied completely on manual compression of the vascular pedicle for 2 min and did not refill until the compression was released. This evidence suggests that the free flaps do not receive significant blood flow through vessels across the flap inset, and are therefore significantly dependent for vascularity on the original anastomoses even 1 year after surgery.