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Page 2 of 10 García Nores et al. Plast Aesthet Res 2023;10:33 https://dx.doi.org/10.20517/2347-9264.2022.146

INTRODUCTION
Autologous free tissue transfer is considered a safe, common, and highly successful technique for breast
reconstruction. The historical evolution from the pedicled transverse rectus abdominis muscle (pTRAM) to
free TRAM (fTRAM), then muscle-sparing TRAM (msTRAM), and finally deep inferior epigastric artery
perforator (DIEP) or superficial inferior epigastric artery (SIEA) flaps has been remarkable but also
introduced new challenges. Important advancements in preoperative flap planning, harvest, and
postoperative monitoring have significantly decreased the rate of major complications such as total flap loss.
Furthermore, working in multidisciplinary teams when planning for immediate autologous reconstruction
allows for better planning and therefore better outcomes. However, several minor complications are still
routinely encountered, including donor site morbidity (e.g., bulge/hernia and wound dehiscence) and
partial flap loss or fat necrosis. While the reported incidence of fat necrosis ranges widely due to
inconsistent postoperative assessment and lack of standardization, a systematic review of 70 articles
conducted by Khansa et al. found a reported incidence of 3.0%-37.9% and the mean rate of fat necrosis to be
[1]
2
11.3% . Widely accepted risk factors include smoking, obesity [BMI (kg/m ) > 30], postoperative radiation
[2]
therapy, and ischemia . While some factors are clearly beyond our control at the time of surgery, there are
certain techniques we can employ to minimize the risks of complications. In this article, we aim to provide a
summary of the current literature on strategies for the prevention and management of partial flap loss (skin
involved) and fat necrosis to best guide today’s surgeon.

PREVENTION
Preoperative imaging
Numerous studies on the value of preoperative imaging for DIEP and other autologous flaps have been
published . Preoperative imaging to map perforator location and intramuscular course has been reported
[3,4]
to decrease operative time, total flap loss, and fat necrosis . This is based on the knowledge that a better
[5]
understanding of perforator course will help delineate vascular territories and therefore minimize fat
necrosis in under-perfused areas. The most common imaging modality utilized is CT Angiography (CTA),
but similar benefits have been reported using MR Angiography (MRA) and even ultrasound . There is
[6]
always a concern for the cost of imaging, additional radiation exposure, and possible incidental findings
[7]
leading to delays in care and additional workup . MRA is a strong competitor against CTA, as it does not
have any radiation exposure (although the radiation dose of a CTA can now be reduced to as low as 5
millisieverts, which is the equivalent of two abdominal X-Rays) and has a safer contrast allergy profile. MRA
has been described as having a clearer definition of the intramuscular perforators, whereas CTA is superior
in evaluating subcutaneous course. Davis et al. even describe using preoperative imaging to identify atypical
venous connections and predict venous congestion .
[8]
Intraoperative perfusion assessment
The introduction of indocyanine green laser angiography (ICG or SPY angiography) has also proven to be
beneficial for more than mastectomy flap evaluation. This technology allows the surgeon to assess
perforator location and intraoperative tissue perfusion during flap harvest, aiding in perforator selection.
The surgeon can also evaluate tissue perfusion after anastomosis to detect early signs of ischemia or venous
congestion, which could lead to partial or complete flap loss. SPY angiography technology can be employed
intraoperatively to assess the perforasome territory based on the selected perforator for a DIEP flap. The
authors routinely clamp the other perforators temporarily to gauge the perfusion of the skin paddle and/or
adipose tissue. Additional perforators can be harvested if the perforasome territory is deemed inadequate.
Once the flap is transferred and anastomosed, repeat SPY angiography objectively confirms that the flap is
well perfused. This technology is also useful in identifying early or partial venous congestion which may
lead to complete or partial flap necrosis and has been demonstrated to decrease postoperative
complications . Routinely, we repeat the SPY assessment after 15-20 min to assess for fluorescein clearance.
[9]