Page 14 - Read Online

Page 6 of 26 Chen et al. Plast Aesthet Res 2023;10:24 https://dx.doi.org/10.20517/2347-9264.2022.136

Figure 1. ICG angiography of DIEP flaps. (A) Heterogenous ICG appearance consistent with compromised venous outflow; (B)
Homogenous ICG appearance consistent with healthy venous outflow; This figure is quoted from Sharaf et al. published in Microsurgery
by Wiley Periodicals, Inc., copyright 2021 [70] . Reprinted with permission from John Wiley and Sons.

qualities, multiple technologies have since emerged, often used in combination with conventional
techniques.

Physical examination
Physical examination is a commonly practiced method for assessing flap viability. The physical examination
should include an assessment of flap color, temperature, turgor, and capillary refill [74,75] . Flap temperature
has previously been assessed via touch, temperature probe, temperature-sensitive tape, or handheld
contactless thermometer. However, surface temperature monitoring has not been routinely recommended
in larger perforator flaps due to its inability to detect changes prior to flap failure or predict reoperation in
[76]
DIEP flap breast reconstructions . Bleeding is also an important component of the physical examination in
flap monitoring. This can be ascertained via needle prick or skin incision; however, both of these techniques
can result in transient ecchymosis that may affect accurate flap assessment [74,76] .

The physical examination can aid in determining the etiology of flap thrombosis. An arterial thrombosis can
be characterized by a cool and pale appearing skin paddle, diminished turgor, and delayed capillary refill.
On the contrary, venous thrombosis is often characterized by an edematous and mottled appearing skin
[75]
paddle with brisk (< 1-2 seconds) capillary refill, increased turgor, and bleeding on needle prick .

Vascular flow
Physical examination is typically accompanied by a more objective assessment of vascular flow. Currently,
the most widely used techniques include those that monitor vascular flow and those that monitor tissue
ischemia [Table 1]. The most commonly used objective assessment is intermittent interrogation of blood
flow with an acoustic Doppler. While handheld acoustic Doppler sonography is not capable of performing
continuous monitoring, it is a widely available, cost-efficient, and non-invasive method for monitoring
vascular flow that can be easily operated by house staff .
[77]
Additional Doppler technologies have since been developed to allow for continuous flap monitoring,
including the Cook-Swartz implantable Doppler, flow coupler implantable Doppler, and laser Doppler
[78]
flowmetry . Given the invasive nature of implantable Doppler, some authors suggest that vessel
compression and anastomotic injury by the implanted cuff or wire should be considered . In addition,
[79]
laser Doppler is a promising non-invasive option but lacks consensus values for detection and thus remains
experimental .
[80]
At our institution, we recommend regularly spaced intervals of acoustic Doppler sonography, ideally in
combination with continuous tissue oximetry-based monitoring. However, implantable Doppler is used for