Background : Masculinizing gender-affirmation surgery is commonly accomplished using radial forearm free flap (RF) phalloplasty. These flaps provide a unique challenge to the reconstructive surgeon as the flap is a tubularized structure with limited capacity for swelling before resultant compromise to the flap vascular supply. Historically, free flap phalloplasty necrosis rates have been reported in the range of 3.4 - 25 percent. We hypothesize that venous congestion in the urethral segment is the primary source of edema in double-tube phalloplasty reconstruction. With a limited flap volume, urethral edema causes a compartment syndrome-like effect, further limiting venous outflow and eventually leading to partial or complete flap loss. Our group has sought to avoid this devastating outcome by ensuring venous drainage specifically to the urethral segment (often with a secondary venous anastomosis), in combination with perioperative fluid limitation and early flap decompression with significant edema. The outcomes of 41 consecutive radial forearm flaps over 13 months were prospectively followed, with particular attention to partial or complete flap loss and the need for reoperation.
Methods : Preoperatively, fluid management is discussed with the anesthesia team with a goal of 2 or fewer liters of intraoperative fluid. During flap harvest, any superficial veins serving the urethral segment are dissected; if these drain to the profunda cubitalis vein a single anastomosis is performed, otherwise the peri-urethral veins are prepared for additional microvascular anastomosis. Postoperatively, intravenous fluids are discontinued on postoperative day one and administered as needed. Flaps are monitored with clinical exam and both external doppler and implantable venous doppler. If flap compromise due to edema is suspected, the phallus is decompressed urgently with release of the outermost suture line and diuretics are administered. Flap complications were assessed over the study period. Complications included need for takeback, infection, partial flap necrosis, glans atrophy, dehiscence, or persistent edema.
Results : Over 13 months from 10/2017 to 11/2018, 41 consecutive patients underwent RF phalloplasty reconstruction. All flaps were double-tubed including pars pendulans reconstruction. Primary glansplasty was performed in 60.9% of cases.
There was zero incidence of complete or partial flap loss. Two flaps (4.8%) were found to be edematous and required urgent ventral decompression but were rescued and managed with skin grafting of the ventral phallus. Two different patients (4.8%) required operative groin exploration for venous obstruction and groin hematoma within the first postoperative day but did not require phalloplasty decompression and had no flap loss. The mean follow-up period was 7.5 months.
Conclusions : Flap-threatening edema in radial forearm phalloplasty may result from congestion in the ulnar-most flap, which comprises the urethral segment and forms the inner tube in double-tube formation. A standardized approach in flap design with harvest of a urethral draining vein may decrease flap edema. In instances edema compromises flow, perioperative fluid management and early flap decompression are able to prevent flap loss. Utilizing this algorithm, no flap failures have yet occurred. Analysis of long-term urethral complications will provide additional information regarding perfusion of the urethral inner-tube. This protocol in flap design and perioperative management appears safe and effective.