Page 428 - Read Online

Page 10 of 13 Singh et al. Plast Aesthet Res 2020;7:39 I http://dx.doi.org/10.20517/2347-9264.2019.76

Abdominal wall vascularized composite allograft
Multiple techniques have been described to help achieve abdominal wall closure including component
separation, Gortex patch, use of biologic mesh (as described above), autologous flaps, and more recently
abdominal wall transplantation. Abdominal wall transplantation, more commonly known as abdominal
wall vascularized composite allograft (AW-VCA), is a modern alternative to abdominal wall closure
which is typically reserved for truly complex defects. Utilization of AW-VCA can be separated into three
categories: (1) patients receiving AW-VCA in conjunction with intestinal transplant; (2) patients receiving
AW-CVA who already have a visceral organ transplant such as liver, kidney, or pancreas; and (3) AW-CVA
performed as an isolated soft tissue transplant, which has shown promise in cadaver models. It is
important to note that in non-transplant patients performing AW-VCA will subject patients to lifelong
immunosuppression. On the contrary, for transplant patients, they are already immune suppressed.

AW-VCA can be either partial or full-thickness. In full-thickness transplants, the abdominal wall -
including the peritoneum, rectus abdominis muscle(s), and variable amounts of oblique muscle, as well as
skin and soft tissue - are harvested en bloc. Partial-thickness reconstruction involves vascularized or non-
[25]
vascularized fascia in patients with adequate skin cover, but insufficient or inadequate fascia .
Two techniques have been described for abdominal wall transplants. In the conventional method, blood
supply from the donor is taken from the inferior epigastric vessels, which are left in continuity with the
[12]
femoral and iliac vessels and then anastomosed to the recipient’s common iliac artery and vein . The
second method uses a microvascular technique to anastomose the donor’s inferior epigastric vessels
to those of the recipient . The fascia of the donor is then sutured to the abdominal wall fascia of the
[26]
recipient. A layered closure involving the subcutaneous tissues and skin of the donor and recipient is then
performed, thereby completing graft integration. In both techniques, the abdominal donor graft is taken
from a beating-heart donor. Procurement ideally is taken from the same donor of the abdominal organs.
Interestingly, there have been reports of procurement from abdominal wall-specific donors.

Levi’s group in 2003 was the first group to report their experience in a nine-case series of abdominal wall
[12]
transplants . This series included adults and children and was later pooled with additional patients in
2009 . Noted indications for intestinal transplant in their series included Gardner’s syndrome, trauma,
[27]
[12]
Churg-Strauss vasculitis, and intestinal motility disorders such as Hirschsprung and pseudo-obstruction .
Since the initial report in 2003, there have been 35 cases of AW-VCA transplantation with flap survival
rates as high as 88% with immunosuppression [25,28] .

Postoperative immunosuppression protocols are center-specific. These regimens commonly include
antibody induction with maintenance therapy using tacrolimus and/or mycophenolate mofetil. Steroids
may also be used during maintenance therapy. One study noted a rejection rate of 17.7% among a cohort of
17 patients . Rejection of the graft is often accompanied by a maculopapular rash or skin breakdown. This
[29]
is in part due to the strong antigen surveillance role played by Langerhan cells within the skin, which may
demonstrate signs of rejection when other composite tissues may not. Early skin changes on the abdominal
wall are an indication of rejection and thus treatments such as steroid boluses and medication adjustments
can be initiated sooner. Rejection may respond to topical immunosuppressive application as well or in
conjunction with oral steroids The added benefit of a skin rash is being a sentinel marker of infection that
provides a visual which patients may share with their transplant team, prompting intervention sooner than
would be otherwise. Furthermore, because transplanted skin can act as a marker of visceral rejection via
a rash, patients may have immunosuppressive regimens titrated down as long as such symptoms do not
[30]
occur . It is worth noting that multiple studies have reported that deaths after transplantation have not
been directly related to abdominal wall transplants.