Three- and four-dimensional computed tomographic angiography and venography of the anterolateral thigh perforator flap

Background: This study presents a detailed three- and four-dimensional appraisal of the arterial and venous anatomy and perfusion of the anterolateral thigh flap using a novel computed tomographic technique. Methods: Eighteen anterolateral thigh flaps harvested from fresh Western cadavers were used. Four-dimensional computed tomographic angiography with injection of iodinated contrast medium into isolated perforators and their venae comitantes was used to investigate the arterial and venous anatomy and flap perfusion. Additional perforators were injected to investigate the vascular connections within the flap. Changes in flap perfusion after thinning and adipo-fascial flap harvest were also examined, and contrast density within each flap plexus with respect to the perforator was examined. Results: Large-diameter linking vessels at the suprafascial level enabled perfusion of adjacent vascular territories and of the subdermal plexus between angiotomes. Thinning reduced the size of the vascular territory by ligating recurrent vessels at the level of the suprafascial plexus. Adipofascial flap harvest prevented perfusion of the recurrent vessels, demonstrating the role of the subdermal plexus in recurrent flow. Three distinct perforator complex patterns were found with relevance to flap thinning. A superficial venous system perfused the venae comitantes of the descending branch of the lateral femoral circumflex artery and the long saphenous vein. Conclusions: A reduction in vascular territory occurs in the anterolateral thigh flap after thinning and is attributable to ligation of vessels within the suprafascial plexus. Recurrent flow through the subdermal plexus was seen dynamically for the first time and appears to be an important mechanism for skin perfusion.