Two Easy and Simple Modifications When Using a Distally Based Sural Flap to Reduce the Risk of Venous Congestion

Abstract

Sir: We want to congratulate Loonen et al. for their very interesting publication.1 They describe an anatomical study performed on five human cadaver legs. In addition, they performed a duplex sonographic study on five legs of three young healthy volunteers. The results are indeed very interesting and, more important, of clear clinical relevance and with high clinical implication. As mentioned in their article, the use of the distally based sural flap seems to have a definite risk of postoperative complication. As the distally based sural flap is a retrograde perfused flap, the venous valves are unfavorable for venous drainage of the flap. In addition, the neurovascular pedicle of the distally based sural flap usually has to be rotated nearly 180 degrees. This procedure also favors venous congestion of the flap. As already published in 2005 by Kneser et al.2 and in 2007 by Bach et al.,3 our department has considerable clinical experience with the use of distally based sural flaps and other distally based flaps of the lower extremity. Our clinical findings and experience support the anatomical findings published by Loonen et al. To minimize the incidence of venous congestion with consecutive partial or total necrosis of the sural flap, we usually perform the following two modifications: We usually include the cutis and subcutis with the neurovascular pedicle of the sural flap. Therefore, our sural flaps are by definition not true island flaps. However, in our hands, this modification enhances the venous drainage of the sural flap by using the subdermal venous plexus and helps to prevent undue tension or torque on the pedicle. If venous congestion of the sural flap is diagnosed during the operation or even postoperatively, we perform a venous anastomosis of the proximal end of the sural flap vein with a subcutaneous vein found locally in the region of the former defect. Especially in patients who needed a very long pedicle and coverage at a far distal point on their lower extremity, we experienced full flap survival when anastomosing the saphenous vein to a local recipient, with complete resolution of the venous congestion (Fig. 1). We can therefore confirm that the authors’ theoretical concept does work very well clinically also. These two modifications are easy and simple methods that are used in our institution if venous congestion of a distally based sural flap occurs.Fig. 1.: (Left) Distally based sural flap with 180-degree rotation of a very long pedicle (asterisk), which includes the cutis and subcutis and thus the subdermal venous plexus. (Right) Distal zone of the sural flap 1 week after completion of a venous anastomosis (V) of the proximal end of the sural flap vein with a subcutaneous vein found locally in the region of the former defect.Adrian Dragu, M.D. Alexander D. Bach, M.D. Ulrich Kneser, M.D. Raymund E. Horch, M.D. Department of Plastic and Hand Surgery University Hospital Erlangen Erlangen, Germany