The medial sural artery perforator flap (MSAP) is useful for reconstructing thin, pliable regions such as the palm and foot and can include the great saphenous vein as a donor vein or be converted into a free muscle flap using the medial gastrocnemius. We reviewed four free MSAP performed between December 2023 and June 2025. Patients (three men, one woman; aged 54–77 years, mean 65.8) had defects caused by infection (palm 1, foot 1) , frostbite (1) , and trauma (1) . Flap sizes ranged from 10×5 cm to 18×7 cm. One flap developed venous congestion on postoperative day 1 and necrosed, requiring transfer of an anterolateral thigh flap. The other three survived; in one case, perforator injury required conversion to a medial sural artery free muscle flap followed by delayed skin grafting. Donor veins were venae comitantes in three cases and the great saphenous vein alone in one. Necrosis likely resulted from kinking at the dorsoplantar junction and vascular compression. Adequate flap length and gentle positioning are essential. Even with a single great saphenous vein, flap survival was satisfactory, confirming its reliability as a drainage route.
