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Page 16 of 26 Chen et al. Plast Aesthet Res 2023;10:24 https://dx.doi.org/10.20517/2347-9264.2022.136

Alternative venous drainage
Several methods exist for the medical management of venous insufficiency in free flaps, with varying levels
[127]
of success demonstrated in the literature . Local injection of subcutaneous heparin has been demonstrated
to be effective in several studies. More recently, the use of subcutaneous heparin was discussed by Perez et
al, who showed that local subcutaneous injection of LMWH is an effective method for flap salvage in cases
[135]
of venous congestion .
Relief of venous congestion may be further facilitated by pricking or de-epithelialization of the flap. Pricking
[136]
the flap with a needle allows blood loss from the congested area, thereby reducing venous compromise .
In a similar manner, de-epithelializing a portion of the flap allows for venous drainage. Heparin may be
injected into the de-epithelialized area or a heparin-soaked gauze may be applied to the de-epithelialized
area to further increase venous outflow [136,137] .

Hirudotherapy, the use of medicinal leeches, may be used in cases of irreparable venous insufficiency and/or
flap necrosis secondary to venous compromise. The application of leeches provides temporary relief of
venous congestion while a more reliable network for venous drainage is being established [127,138] . The
effectiveness of medicinal leech therapy in decreasing venous congestion is two-fold; the initial blood meal
by the leech allows for active drainage of ~5-15 mL of congested blood, after which passive blood loss from
the bite injury continues to occur. Leech-mediated release of vasoactive substances allows for further local
thrombolysis and anticoagulation [139,140] . While leech therapy for free flap salvage has reported success rates
ranging from 60-80%, it may be less effective for higher volume flaps such as TRAM or DIEP flaps [127,138] .
Primary complications of leech therapy include infection and anemia . The evidence for medicinal leech
[139]
therapy is limited to case series and retrospective studies. While Pannucci et al. found that leech therapy in
microvascular breast flaps was associated with higher flap loss rates, this is likely secondary to significant
selection bias . Current evidence indicates that leech therapy should be used with discretion and in
[141]
consideration of patient-specific risk factors . In our experience, leech therapy should be considered as an
[141]
adjunct in cases with significant intra-flap venous insufficiency that does not respond adequately to other
therapies.

Veno-cutaneous catheterization presents another option for the relief of venous congestion. An
angiocatheter is placed into a superficial vein at the margin of the flap. Distilled heparin solution is injected
into the vein. The catheter is left in place with a valve such that venous drainage may occur as needed.
When clinical signs of congestion improve, the catheter may be removed [142-144] . In comparison to leech
therapy, veno-cutaneous catheterization is less costly. Further, Mozafari et al. showed that veno-cutaneous
catheter use is associated with decreased blood loss, wound dehiscence, and flap necrosis compared to leech
[145]
therapy. It is also associated with high rates of nursing and patient satisfaction . All reported protocols
indicate that the catheter must be placed in the operating room, which is a notable disadvantage of this
technique . In our experience, venocutaneous catheterization can be difficult to maintain for more than 1-
[127]
2 days, given the high likelihood of catheter thrombosis with intermittent use.

Negative pressure therapy has also been reported in the literature for the management of venous
congestion. However, its use in practice is still rare. Negative pressure therapy is thought to reduce
congestion by decreasing edema, increasing drainage and local venous flow, and increasing the rate of
neovascularization [146-148] . Negative pressure may also have a compressive effect, making the overall benefit of
this therapy difficult to accurately assess .
[127]