Urethral Outcomes of the Labia Minora Ring Flap for Metoidioplasty and Phalloplasty

To determine urethral outcomes of single-stage metoidioplasty and radial forearm free flap (RFFF) phalloplasty using the labia minora ring flap for urethral lengthening (UL).

A retrospective review was performed of patients undergoing single-stage metoidioplasty and RFFF phalloplasty utilizing the labia minora ring flap technique. The ring flap consists of endodermal labia minora tissue ventral to the clitoris and surrounding the vaginal introitus. During metoidioplasty, the ring flap accounts for the entirety of UL. During RFFF phalloplasty, the ring flap becomes the pars fixa (PF) urethra. The primary outcomes measured were rates of fistula, stricture, and surgical revision.

Between November 2017 and August 2023, 311 patients underwent metoidioplasty or RFFF phalloplasty (mean follow-up 37 months). Of the 69 metoidioplasties, urethrocutaneous fistulas developed in 11 patients (16%); strictures occurred in 4 (6%). Of the 242 phalloplasty patients, there were 71 fistulas (29%), 56 of which resolved spontaneously. Strictures developed in 44 patients (18%). Twenty-five patients (10%) developed both a stricture and fistula. Surgical repair was required in 8/69 (12%) metoidioplasty patients and in 46/242 (19%) RFFF phalloplasty patients for an overall revision rate of 17%.

UL during metoidioplasty or RFFF phalloplasty can be accomplished in a single stage using the labia minora ring flap with comparable surgical revision rates to previously described techniques. This approach can also be applied to other phalloplasty techniques. Many fistulas of the PF urethra resolve spontaneously. Higher urethral revision rates were seen in phalloplasty compared to metoidioplasty.