Modified distally based sural neuro-veno-fasciocutaneous flap: anatomical study and clinical applications

The distally based sural neuro-veno-fasciocutaneous flap has been used widely for reconstruction of foot and ankle soft-tissue defects. The distal pivot point of the flap is designed at the lowest septocutaneous perforator from the peroneal artery of the posterolateral septum, which is, on average, 5 cm (4-7 cm) above the lateral malleolus. A longer neuro-veno-adipofascial pedicle would be needed to reversely reach the distal foot defect when the flap is dissected based on this perforating branch, which may result in more trauma in flap elevation and morbidity of the donor site. In this article, we explored new pivot points for this distally based flap in an anatomic study of 30 fresh cadavers. The results showed that the peroneal artery terminates into two branches: the posterior lateral malleolus artery and lateral calcaneal artery. These two branches also send off cutaneous perforators at about 3 and 1 cm above the tip of lateral malleolus, respectively, which can be used as arterial pivot points for the flap. A communicating branch between the lesser saphenous vein and the peroneal venae comitantes was found, accompanied by the perforator of the posterior lateral malleolus artery. This modified, distally based sural flap with lower pivot points was successfully transferred for repair of soft-tissue defects in 21 patients. The size of flaps ranged from 4 x 3 cm to 18 x 12 cm. All flaps survived without complications. Neither arterial ischemia nor venous congestion was noted. In conclusion, the vascular pivot point of a distally based sural flap can be safely designed at 1.5 cm proximal to the tip of the lateral malleolus. This modified flap provides a valuable tool for repair of foot and ankle soft-tissue defects.