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On “Maximizing the Reliability and Safety of the Distally Based Sural Artery Flap (J Reconstr Microsurg 2008;24:589–594)”
26 March 2009 (online)
We read with great interest Wong and Tan's article on maximizing the reliability and safety of the distally based sural artery flap. We compliment the authors for their extensive literature analysis and description of various controversies regarding the distally based superficial sural artery flap. We also agree that this flap is very useful for soft tissue coverage involving the distal third of the leg, ankle, and the proximal dorsal foot. As an axial flap with a distal pivot point and a narrow but long pedicle, the arc of rotation can be very large. This flap can even be used in patients with diabetes or arteriosclerosis and who have had a revascularization bypass procedure. In these selective cases, the flap can be delayed to maximize vascularity.
We have successfully used this flap regularly over the years. There is, however, some morbidity associated with harvesting the sural artery flap, specifically the secondary hypoesthesia incurred in the territory of the sural nerve. Although rare, patients do complain of complications in 7.1% of cases. Armed with current anatomic knowledge of the blood supply of the superficial venous and nervous system of the lower leg, we have been successfully harvesting the distally based sural artery flap without including the sural nerve.
We have initiated a study of the skin microvasculature of the distally based superficial sural artery flap based on the distal fibular perforator, using three- and four-dimensional computed tomographic angiography. This technique has previously been used to study the vasculature of perforator flaps. Initial results show that:
While harvesting the distally based sural artery flap, the arterial supply to the sural nerve and to the lesser saphenous vein are two parallel systems arising from a common fibular perforator (Fig. 1). There are no direct arterial branches coming from the sural nerve arterial network in the proximal part of the leg. And in the distal part of the leg (after crossing the deep fascia), the arterial branches coming from the sural nerve network are reaching the lesser saphenous arterial network before supplying the skin (Fig. 2). The skin territory vascularized by the lesser saphenous arterial network is similar to the territory vascularized when both systems (vein and nerve) are included in the flap (Fig. 3).
Figure 1 The fibular perforator (a) arises posteriorly to the peroneus brevis muscle. The perforator is then separated into a venous branch for the lesser saphenous vein (b) and nerve branch for the sural nerve (c). The bifurcation is a communicating branch between these two networks (d). When the flap is harvested while sparing the sural nerve, the deep fascia can be opened longitudinally along the nerve for a distance of 4 cm, until the communicating branch is reached, to increase the arc of rotation.
Figure 2 Communicating branches between the neural and the venous networks. There is no direct branch from the sural nerve to the skin. The sural nerve (a) crosses the deep fascia (b), the neural arterial network (c), the lesser saphenous vein (d), the subcutaneous fat tissue (e), the communicating branches between neural and venous networks (f).
Figure 3 Three-dimensional computed tomographic angiography of the entire posterior skin of the leg harvested as a distally based superficial sural artery flap. The left figure (A) shows the vascular territory of a distally based superficial sural artery flap including both the sural nerve and the lesser saphenous vein. The right figure (B) shows the vascular territory of the flap including only the lesser saphenous vein. Both images show a similar vascular territory, which indicates that the inclusion of the sural nerve is not critical for the flap arterial blood supply.
In conclusion, based on the arterial supply of this flap, the sural nerve is not required to safely harvest a distally based pedicle sural artery flap. For the venous drainage of this flap, it is necessary to include the parallel veins of the lesser saphenous vein or to perform a venous anastomosis of the proximal lesser saphenous vein to a local recipient vein if there is venous congestion.
- 1 Wong C H, Tan B K. Maximizing the reliability and safety of the distally based sural artery flap. J Reconstr Microsurg. 2008; 24 589-594
- 2 Xu G, Lai-Jin L. The coverage of skin defects over the foot and ankle using the distally based sural neurocutaneous flaps: experience of 21 cases. J Plast Reconstr Aesthet Surg. 2008; 61 575-577
- 3 Karacalar A, Idil O, Demir A, Güneren E, Simşek T, Ozcan M. Delay in neurovenous flaps: experimental and clinical experience. Ann Plast Surg. 2004; 53 481-487
- 4 Touam C, Rostoucher P, Bhatia A, Oberlin C. Comparative study of two series of distally based fasciocutaneous flaps for coverage of the lower one-fourth of the leg, the ankle, and the foot. Plast Reconstr Surg. 2001; 107 383-392
- 5 Nakajima H, Imanishi N, Fukuzumi S et al.. Accompanying arteries of the lesser saphenous vein and sural nerve: anatomic study and its clinical applications. Plast Reconstr Surg. 1999; 103 104-120
- 6 Saint-Cyr M, Schaverien M, Arbique G, Hatef D, Brown S A, Rohrich R J. Three- and four-dimensional computed tomographic angiography and venography for the investigation of the vascular anatomy and perfusion of perforator flaps. Plast Reconstr Surg. 2008; 121 772-780
- 7 Loonen M P, Kon M, Schuurman A H, Bleys R L. Venous bypass drainage of the small saphenous vein in the neurovascular pedicle of the sural flap: anatomical study and clinical implications. Plast Reconstr Surg. 2007; 120 1898-1905
- 8 Belmahi A, Oufkir A A, Fejjal N. A simple way to secure the distally based fascio-cutaneous flap of the leg: the lesser sapheneous-greater sapheneous vein anastomosis. Report of 15 clinical cases. Ann Chir Plast Esthet. 2007; 52 89-95
Ali Mojallal, M.D.
Hopital Edouard Herriot, Plastic Surgery
Place d'Arsonval Lyon, France 69003