Reply: Technical Description and Microsurgical Outcomes in Phalloplasty Using the Deep Inferior Epigastric Artery and Locoregional Veins.

Abstract

Sir: We appreciate the comment regarding our article1 by Dr. Cheng et al., which is based on their extensive experience with this particular reconstruction. Our evolution toward a dual-outflow flap was driven by an early series of venous complications and flap take-backs. In addition to the sheer size of the flap, as mentioned by Cheng et al., tubularizing it in two directions can further increase the risk for vascular compromise. In the absence of solid data, we let our practice be guided by individual failures and are reluctant to repeat what has previously failed. In one patient in our series, a free ulnar forearm flap for urethral reconstruction failed on postoperative day 6. In this case, the comitantes of the ulnar artery had been connected to the deep and superficial inferior epigastric veins, which was the only time the superficial inferior epigastric vein was used. The greater saphenous vein is reliable and, in our opinion, a better size match for the cephalic vein. How many veins are required for adequate outflow? In general, this is determined by the choice of flap and the flap size. In the vast majority of free flaps, the venous anatomy allows for drainage through various H-branches and connections between deep and superficial venous systems, allowing for adequate outflow through a single vein. In particularly large free flaps such as the deep inferior epigastric perforator flap, either the deep or superficial system may be dominant, making additional venous drainage beneficial or even necessary. The available data regarding single versus dual outflow for radial forearm flaps are based on flaps that are much smaller than what is used for phalloplasty. Inadequate venous drainage through one system is a scenario that would present acutely in the operating room rather than in the postoperative period either by clinical examination or with the assistance of indocyanine green angiography, as mentioned by the authors. Causes of postoperative venous congestion in our series were more likely to be attributed to compressive forces from fluid accumulation (e.g., seroma/hematoma), kinking of the singular vein, or a technical issue. At our center, we have gravitated toward the addition of the deep inferior epigastric vein to provide this additional “backup” vein that takes a more direct and shorter trajectory into the deep venous system. The superficial inferior epigastric vein still crosses the groin crease and, in our opinion, has an inferior size match with the greater saphenous vein. Another consideration is whether portions of the flap that cannot be directly inspected, and are vulnerable based on tubularization, should be “super drained.” This approach has been advocated by Chen and Safa,2 where a branch of the basilic vein is anastomosed. However, in our experience, this has not been necessary. Both the proximal and distal aspects of the neourethra are visible in the “Big Ben method” of staged phalloplasty. We believe that partial flap loss is more likely a function of the limited angiosome of a single arterial inflow than of inadequate outflow. The body of granular literature for optimization of phalloplasty is still lacking. It seems that several experienced phalloplasty surgeons have independently concluded that connection of at least two veins is a worthy and feasible technique. The specific artery or vein(s) used is less important than the microsurgical wherewithal required for this procedure. DISCLOSURE The authors have no financial interest to declare in relation to the content of this communication. Sara Danker, M.D.Jens U. Berli, M.D.Division of Plastic and Reconstructive SurgeryOregon Health & Science UniversityPortland, Ore.