Superficial versus deep: options in venous drainage of the radial forearm free flap

We performed a fresh cadaver dissection study of the superficial venous system (cephalic vein and its branches) and the deep venous system (venae comitantes) of the radial forearm to assess the suitability of each system for venous anastomosis during free tissue transfer. We used methyl methacrylate to evaluate vessel diameters and anatomic variability of both venous systems. Colored radiopaque injectate allowed us to combine anatomic dissection with tissue radiographs. We discovered the cephalic vein to invariably be of larger caliber than the venae comitantes. Ensuring capture of the cephalic vein in the flap necessitated additional dorsoradial subcutaneous dissection beyond the boundaries of the skin flap in four of ten specimens. The vessel diameters of the venae comitantes in four cadavers were less than 2 mm. Proximal confluence of the two venae comitantes, and communication between the deep and superficial venous systems were encountered in only four cases. In these cases, had an anastomotic site been chosen proximal to such a communication to ensure greater vessel caliber, pedicle length probably would have made free tissue transfer unwieldy. We recommend mapping the course of the cephalic vein before flap elevation and maintaining a wide proximal subcutaneous pedicle to capture the best possible superficial drainage system. If the superficial venous system has been damaged (as by previous intravenous catheterization), one may not necessarily be able to rely on the vessel caliber of the deep venae comitantes for microvenous anastomosis.