Sural perforator flap: assessment of the posterior calf region as donor site for a free fasciocutaneous flap.

Three kinds of free fasciocutaneous flap from the posterior calf region have been described in the literature: the medial sural perforator flap, the lateral sural perforator flap, and the traditional posterior calf fasciocutaneous flap that is supplied by superficial cutaneous vessels. Moreover, it has been reported that superficial cutaneous vessels are of a suitable size for microanastomosis when deep musculocutaneous perforators are absent or relatively tiny. To establish a safe technique for free fasciocutaneous flap elevation from the posterior calf region, we examined the number and location of the musculocutaneous perforators and the size of superficial cutaneous vessels at their origin from the popliteal artery in six formalinized cadavers. We found that all legs had at least one perforator either from the medial sural artery or the lateral sural artery. By contrast, we failed to find superficial cutaneous vessels of suitable size for microanastomosis in three legs, and there was no significant inverse relationship between the diameter of the superficial cutaneous artery and the number of musculocutaneous perforators. Our results suggest that the medial sural perforator flap and the lateral sural perforator flap might be the surgeon's first and second choice, respectively. The traditional posterior calf fasciocutaneous flap should be the third choice because our study suggests that its availability is doubtful. Another site is recommended, when preoperative Doppler study suggests that the existence of musculocutaneous perforator is in doubt. Two clinical cases, with a medial sural perforator flap and a lateral sural perforator flap, respectively, are presented.