Page 365 - Read Online

Page 10 of 15 Carter et al. Plast Aesthet Res 2020;7:33 I http://dx.doi.org/10.20517/2347-9264.2020.81

Additional nerves that are present in the flap may also be anastomosed to the ilioinguinal nerve, further
improving light touch sensation to the neophallus [11,12] .

[30]
The technique of microsuturing the epineurium has imperfect functional outcomes . The axons from
the distal natal nerve must traverse the anastomosis and reach the proximal segment of the donor nerve.
Any anastomotic site scarring or fibrosis may create a mechanical impediment to the axons and limit
[30]
reinnervation outcomes . In addition to joining the aponeuroses with several sutures, we augment the
nerve repair with a fibrin sealant (Tisseel®; Baxter Healthcare; Deerfield, IL or an equivalent product). This
serves to mechanically protect the nerve repair during the remaining surgery, and from pulling during
patient movement [31,32] . Our patients have had favorable nerve regeneration outcomes after phalloplasty;
about 80% achieve erogenous sensation in the neophallus, and up to 95% achieve light touch sensation in the
neophallus. A notable 5% have no sensation to the neophallus whatsoever.

In order to further increase the speed and outcome of nerve regeneration, we have studied the use of
TM
nerve conduit wraps intended for peripheral nerve repair, such as the Axoguard Nerve Protector Wrap
(Axogen; Alachua, FL) to augment the standard end-to-end surgical technique. The ideal nerve wrap is non-
immunogenic, strong enough to resist degradation and compression, and prevents both scarring and nerve
[33]
TM
adhesion formation . The Axoguard implant is a sheath made of porcine extracellular matrix (ECM)
from small intestinal submucosa [33,34] . Its acellular matrix is composed of collagen, fibronectin, growth factors,
glycosaminoglycans, proteoglycans, and glycoproteins, all which may promote neural tissue revascularization
through the induction of cellular proliferation/differentiation as well as the deposition of host ECM
components [33,34] . It provides a physical barrier around the anastomosis, potentially protecting it from cellular
[33]
infiltration and allowing the nerve to glide normally during movement . With other surgical indications,
it has been shown to decrease nerve scarring during healing, with favorable functional outcomes [33,34] . We
will continue to investigate the role of these ECM nerve connection sheaths to see if they will improve the
efficiency of nerve regeneration over fibrin sealant alone.

POSTOPERATIVE FLAP MONITORING & FLAP COMPLICATIONS
The immediate postoperative healing period is crucial to phalloplasty flap survival. Notable potential
complications include infection, hematoma, wound dehiscence, urethral loss, partial phallic loss, and full
[9]
phallic loss . These complications are most frequently due to vascular compromise, often venous congestion
leading to potentially irreversible tissue injury [35-37] . The flaps used in phalloplasty pose an additional
challenge: they are much larger than most free flaps used for other tissue coverage indications, are freely
mobile, are anchored only at the base, are in a dependent position, and are positioned close to a natural
[6,9]
flexion point of the body . Partial and total phallic loss are devastating complications for both the patient
and surgeon.

An estimated 1%-9% of free flaps across all indications are lost due to vascular compromise [4,35-38] with
an estimated 95% of losses occurring during the first 24-72 h after surgery [37,39] . At our center, the rate of
flap compromise requiring reoperation after RFF phalloplasty is less than 1%, and much lower after ALT
phalloplasty. We currently have a 0% rate of acute, total neophallus loss. Even in those rare patients with
arterial/venous thrombosis in the early postoperative period, in our cohort of > 750 phalloplasty patients
we have not lost any flaps to acute graft thrombosis. Similarly, clinically significant partial flap loss is rare
at our center, although instances of partial flap compromise may contribute to urethral stricture and/or
fistula development (20% and 22% at our center, respectively). This is likely because of several factors: our
use of continuous flap oxygen monitoring, attentive expert bedside nursing, an on-call team of two surgeons
available at all times for emergency revision surgery, and the optimization of techniques made possible by a
large volume experience.