How Black is Black?: The Curious Case of Lower Extremity Reconstruction with Free Anterolateral Thigh Flaps with a Phenomenon of Complete Dermal Necrosis but Viable Sub-Dermal Components

Microsurgery and free tissue transfer remain a valuable option in the reconstruction of lower extremity trauma for coverage of exposed vital structures, when options for local or regional soft tissue cover are limited. The success rate, however, is relatively less for lower extremity-free flap reconstructions as compared to other locations. Vascular insufficiency, especially venous thrombosis, contributes to this. Late venous insufficiency affects the distal part of flap vasculature, causing small vessel thrombosis. Herein, we describe three cases where free tissue transfer done for lower extremity trauma and burns showed delayed venous insufficiency, with complete skin necrosis of the entire flap. After initial re-exploration, where the anastomosis was found to be patent, the sub-dermal components of the flap were salvaged in its entirety through watchful waiting, anticoagulation therapy, negative pressure wound therapy, and subsequent skin grafting. The remaining flap served the purpose of coverage for the exposed vital structures of the foot.