A dye study in fresh cadavers to outline retrograde flaps of the lower limbs and to examine clinical implications

The reconstruction of distal lower limb defects to meet functional and cosmetic requirements is challenging. The aim of this study was to ascertain the safe hemodynamic territory of various retrograde flaps that are frequently used. We carried out a dye study on both lower limbs of ten fresh cadavers using methylene blue to assess the safe limit of retrograde flaps of different types (i.e., fasciocutaneous flap, adipofascial flap, and fasciocutaneous flap with adipofascial extension) based on the two lower perforators of the posterior tibial artery. The dye penetrated the vascular network up to 20 cm in the fasciocutaneous flaps from a point 8 cm proximal to the tip of the medial malleolus. The extent of the dye was 40 and 20% less in adipofascial flaps and fasciocutaneous flaps with adipofascial extension, respectively, compared to fasciocutaneous flaps. In live subjects, the safe territory is expected to be about 2 cm more in each flap, based on our clinical observations. These findings are of significance since such flaps can be safely selected for various defects depending on their location, their dimensions, and the availability of suitable local tissues.