Common Mistakes that Make the Anterolateral Thigh Flap Unreliable for the Beginner

It has been two decades since the description of the anterolateral thigh (ALT) flap; however, skepticism still prevails in certain parts of the world about the reliability of this donor site. The aim of this presentation was to systematically evaluate the pitfalls that a beginner could experience in flap dissection, in order to simplify flap harvest and decrease dissection time. The experience is based on 85 flaps performed in various reconstructive procedures in the last 5 years.

The first mistake is to consider the ALT flap as a septocutaneous flap, which is a myocutaneous flap of the vastus lateralis muscle in 85% of the cases. Therefore, an indication requiring a thinner flap will necessitate perforator flap dissection, which might be difficult or unexpected for the inexperienced surgeon. The second mistake is to rely on a hand-held Doppler in flap design, which has been shown to have only a 40% correlation with the actual perforators. When required, a color Doppler study should be performed instead, which is even capable of discriminating between septocutaneos and myocutaneous perforators. The third mistake is to plan and incise the skin flap before identifying the perforator status. In addition, incision and dissection should begin from the medial aspect, never circumferentially.

The fourth mistake is to be lost in the anatomic variations published. These variations are limited to 10% of cases, and those which make this donor site invalid are less than 4%. It should also be noted that the vessel referred to as perforators in one article may not be the same type of vessel described in the next. This is particularly true for the earlier studies that frequently reported absence of the perforators; they were referring to the absence of septocutaneous perforators, as the perforator flap concept based on myocutaneous perforators was not available yet. The fifth mistake is to start dissection of a perforator from periphery to center without identifying the proximal main vessel. This may lead the surgeon to other pedicle dissections, thus wasting time. The sixth mistake is to cut the motor nerve to the vastus lateralis muscle due to its twisting around the perforators. It is possible to free the nerve from the vascular pedicle following pedicle division in all single-perforator flaps.

By avoiding these pitfalls, the authors did not encounter any dissection-related flap failures in their series. When the confusion in the nomenclature and knowledge about dissection techniques of the ALT flap are clarified, this flap becomes one of the most versatile and reliable donors.