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Page 4 of 9 O’Connor et al. Plast Aesthet Res 2019;6:26 I http://dx.doi.org/10.20517/2347-9264.2019.38

Flap necrosis
Any surgeon performing complex ventral hernia repair should have an intimate knowledge of the blood
supply to the abdominal wall. The inferior epigastric artery supplies the majority of blood flow to the
rectus abdominis muscle with collaterals to the superior epigastric from the internal mammary. These
send perforating branches anteriorly through the anterior rectus sheath to supply the subcutaneous fat
and overlying abdominal wall skin. The largest concentration of these perforators lies within 10 cm of the
umbilicus in all directions and preservation of this pedicle is paramount in preventing tissue ischemia and
subsequent SSO. This principle has driven innovation in abdominal wall reconstruction to preserve as
[19]
much of the abdominal wall blood supply as possible .

To minimize large subcutaneous flaps that contribute to skin necrosis, retrorectus placement of the mesh
[20]
whenever possible in a “sublay” technique has been widely popularized in recent years . If a component
separation is required for closure of the midline, the debate over wound complication rates between
anterior component separation (ACS) and transversus abdominis release (TAR) still continues. The TAR
repair has been described extensively with very low wound complication rate. In Novitsky’s 2012 paper,
only one of the 42 original patients developed skin flap necrosis with the TAR technique, and this patient
[21]
[22]
had subcutaneous flaps raised during the initial operation . Harth et al. presented similar findings when
studying the flaps raised in panniculectomy during hernia repair. They found a 70% wound complication
rate in the panniculectomy group with 40% requiring return to the operating room for debridement. This
highlights the morbidity associated with large subcutaneous flaps on the abdominal wall when combined
with hernia repair.

For large hernias in which mobility of the anterior elements prevents closure of the linea alba, an ACS
may be required to gain mobility of greater than 15 cm. In this case, a periumbilical perforator sparing
technique preserves blood supply to the skin flap and has been shown to reduce SSO and skin necrosis [23,24] .
This technique involves tunneling around the periumbilical pedicle of perforator vessels to gain access
[19]
to the external oblique muscle release, and can be done either open or endoscopically . If concerns of
ischemia remain, the flap can be evaluated with fluorescence angiography to thoroughly evaluate the
[25]
viability of skin and subcutaneous tissue . The mesh should still be placed in the retrorectus space to
prevent further undermining of the flap, and to provide another barrier between the skin and the mesh
[20]
should skin necrosis or SSI occur .

Interparietal hernia
Interparietal hernias occur in retromuscular repairs due to dehiscence of the posterior rectus fascia/
peritoneal closure, allowing intrabdominal contents to herniate between the posterior fascia and the mesh.
Bowel can become acutely incarcerated in this layer, or adhesions and fistulas can form due to direct
exposure of the mesh to the bowel. This is a rare complication with only small case series in existence, the
largest of which describes 9 (1.8%) cases out of 511 retromuscular hernia repairs. In this series, the majority
of patients presented with acute obstruction within 30 days of the index operation. One patient presented
over 10 months after surgery with resolving abdominal pain and 2 were found incidentally on imaging for
other reasons. Because of its rarity, the diagnosis can be difficult and is often missed because of the atypical
appearance on CT scan. On cross sectional imaging, the posterior sheath can appear as a shelf with fluid,
omentum, or bowel lying between it and the overlying rectus muscles [Figure 1] [26,27] .

Lack of bowel function within a few days of surgery should be treated with a high index of suspicion and
be evaluated with a CT scan to look for acute causes of bowel obstruction. In the case of interparietal
hernia, management then depends on the timing of presentation. In the acute period, the mesh can be in
direct contact with bowel increasing the risk of adhesions. The posterior defect should be bridged with a
piece of absorbable synthetic or biologic mesh; this acts as a barrier between bowel and the mesh to allow