Propeller Flaps and Potential Lymphatic Damage

Propeller flaps have gained significant popularity over the past decades as a local reconstructive option. Although they avoid a free flap procedure, they present several disadvantages such as poor perfusion at the tip of the flap (often the point of greatest need), the inability to work simultaneously with the orthopedic team in the same body region, and the necessity of creating generously sized flaps due to the poor elasticity of the skin, especially in the context of traumatized and edematous limbs.1 In addition to these, there is another important drawback that, according to our literature research, seems to have been overlooked, namely the potential transection and inversion (up to 180 degrees) of long segments of lymphatic collectors. When a propeller flap is islanded, the lymphatic collectors contained within the flap are transected in 2 points (at the proximal and distal end of the flap) and reversed. This inversion causes the valves within the lymphatic vessels to oppose the physiological lymph flow, leading to significant impairment. This risk of lymphatic damage is very high at the medial aspect of the thigh and leg where most of the lymphatic collectors follow the great saphenous vein, especially from the medial knee upward2,3 (Fig. 1). In the lower limb, in fact, there are 4 primary pathways of lymphatic vessels: anterolateral, anteromedial, posterolateral, and posteromedial.4 Three of these pathways eventually converge along the great saphenous vein in the thigh region. Consequently, harvesting a propeller flap in this area could result in the damage of the majority of lymphatic pathways, thereby increasing the risk of clinical consequences, mostly lymphedema of the distal limb.Fig. 1.: Lymphatic collectors (black lines) and the GSV (blue line) have been marked in a healthy patient using indocyanine green angiography and ultrasound, respectively. As already highlighted in previous anatomical studies, collectors are more scattered distally on the leg, and proceeding proximally, they gather around the GSV. Two lines have been marked in green parallel to the GSV at a 3-cm distance as a reference. GSV, great saphenous vein.Propeller flaps planned on perforators of the posterior tibial artery (most of them emerging between the flexor digitorum longus and the soleus muscle)1 and perforators of the superficial femoral artery (usually musculocutaneous or septocutaneous perforators, at the level of vastus medialis and sartorius muscle)5 abundantly invade this lymphatic-rich area. It seems logical that the more proximal the damage to the lymphatic system, the higher the potential risk of clinical consequences (such as lymphedema, lymphorrhea, and lymphocele), as they will impact a longer segment of the lower limb. These considerations could be extended to every type of local flap that distorts the lymphatics. However, we believe that propeller flaps are particularly risky because they transect and rotate long segments of the collectors. It is important to emphasize that the human body can regenerate a damaged lymphatic system, and this also applies to skin flaps, and alternative lymphatic routes distant from the operated areas can also be enhanced. However, this regeneration is often unreliable and insufficient, and it is our strong belief that a more anatomically respectful and conservative approach should be considered.6 Moreover, the donor site of propeller flaps, on many occasions, even needs to be skin grafted, thus creating an additional barrier in the difficult lymphatic pathway’s regeneration. In our opinion, propeller flaps can on many occasions be planned in such a way that they maintain their clinical utility while reducing the risk of unwanted iatrogenic damage (Fig. 2).Fig. 2.: Patient with a soft tissue sarcoma of the distal medial thigh (black circle). The GSV and the accompanying lymphatics have been marked on the skin. At the time of tumor excision, if the resultant defect needs to be filled, a propeller flap can be designed away from the lymphatic collectors, avoiding unnecessary iatrogenic damage. GSV, great saphenous vein.DISCLOSURE The authors have no financial interest to declare in relation to the content of this article.