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Carter et al. Plast Aesthet Res 2020;7:33 I http://dx.doi.org/10.20517/2347-9264.2020.81 Page 5 of 15

Figure 4. Delayed anterolateral thigh flap ready for use for phalloplasty, 6 months after flap creation. Note that the superior contour of
the flap has not been incised in order to decrease flap edema. Nonviable flap edges (not present in this patient) can be identified and
removed if present at this stage

[3]
thick flap to create the neophallus if the flap thickness is too great . In that case, we do not tubularize the
flap to create the neourethra in the first stage and instead, perform penile urethroplasty in a subsequent
stage. Staged penile urethroplasty is a long, invasive procedure that may have a higher rate of dehiscence
than primary urethroplasty [6,10] . We counsel and caution our patients when pinched anterior thigh skin/fat
thickness is > ½ inch (1.3 cm) and strongly advise against the ALT flap in those with a pinched thigh skin/fat
thickness > 1 inch (2.5 cm).

The ideal management of the too-thick ALT donor site, other than avoidance of this flap, has not been
established. We have created an experimental protocol for patients with thick ALT flap donor sites who
request ALT phalloplasty and will not/cannot consider RFF phalloplasty. The surgery is staged, allowing
for two opportunities to thin the flap while protecting the blood supply in the tissue to be used to make the
neourethra and shaft. We perform a simultaneous subtotal vaginectomy and delay of the flap in the first
stage. The flap is dissected in the usual fashion, except the tissue around its perforators is left unoperated. Fat
deep to Scarpa’s fascia is removed, which moderately reduces phallic girth. The superior incision line is not
created at this time in order to decrease subsequent lymphedema of the flap [Figure 4]. After 6 months, there
is compensatory hypertrophy of the perforators, any tissue loss at the edge of the flap will have occurred and
is discarded, and a second moderate thinning of the flap possible. We do not thin the flap during the typical
single-stage ALT phalloplasty because of the increased risk of devascularizing the flap.

Optimizing the donor template
Donor site dimensions are important when considering the final length and girth of the neophallus,
including sufficient girth for the insertion of a penile prosthetic device. Depending on the anticipated surgical
technique, the flap design may include the penile shaft only, two separate flaps for the penile shaft and penile
urethra, or the TWT flap design. The TWT flap style is a well-established technique and is almost exclusively
used in our high-volume center when urethral extension is desired. The ideal donor site configuration is
unknown, but we have introduced several small modifications that appear to improve outcomes.

(1) Create an “as short-as-possible” urethral extension. This allows the neourethra to protrude from the shaft,
simplifying urethral anastomosis. This urethral extension can theoretically impair blood flow to this portion
of the flap, so we create the shortest possible extension that will allow for tensionless anastomosis.

(2) In order to maximize the proximal urethral blood supply, we spare the dermis medial to the urethral
extension as well as a 2-3 cm zone of subdermal fat superior to the urethral extension.