Methods: The distally based sural flap has been useful for reconstruction of the distal third portion of the lower leg. We retrospectively review in this report the clinical outcomes. Moreover, we studied the vascular anatomy surrounding the sural nerve using preserved cadavers. Twenty-eight consecutive cases of distally based sural flap transfer were reviewed retrospectively. All flaps were harvested with the deep fascia and lesser saphenous vein, but the sural nerve was excluded in all cases to prevent paresthesia. The sural nerve can be easily detached from the flap by meticulous dissection from the deep fascia without causing significant bleeding. In the vascular anatomic study, barium was injected through the femoral artery after elevating the flap in 20 legs of preserved cadavers. Subsequently, tissue specimens were harvested from the upper, middle, and lower sites of the flap for histologic analyses.
Results: Clinically, 22 of 28 flaps survived completely. Distal partial necrosis was observed in 5 flaps, and total necrosis was observed in 1 flap. Causes of total or partial necrosis have been suggested to be dependent on flap shape, pedicle length, and complicating diseases. Anatomic angiography revealed that small extrinsic vessels around the sural nerve and the lesser saphenous vein are important, especially in distally-based sural flap transfer; those around the sural nerve seem to have the most important impact on flap survival. The sural nerve has fewer intrinsic vessels than the extrinsic vessels of the sural nerve and lesser saphenous vein.
Conclusion: The distally based sural flap was useful for reconstruction of the distal third portion of the lower leg. Moreover, these clinical and anatomic findings suggest that the sural nerve can be preserved to prevent surgically induced paresthesia.