ANATOMIC VARIATIONS AND TECHNICAL PROBLEMS OF THE ANTEROLATERAL THIGHFLAP - A REPORT OF 74 CASES

We have transferred 74 free or pedicled anterolateral thigh flaps, inc luding those combined with other flaps, for reconstruction of various types of defects. We report several anatomic variations of the lateral circumflex arterial system and discuss some technical problems with t his flap. Septocutaneous perforators were found in 28 of 74 cases (37. 8 percent), and no perforators were found in 4 cases (5.4 percent). In the 70 cases with perforators, 171 tiny cutaneous perforators (an ave rage of 2.31 per case) were found. Musculocutaneous perforators (81.9 percent) were much more common than septocutaneous perforators (18.1 p ercent). Perforators were concentrated near the midpoint of the latera l thigh, and the selection of perforators as nutrient vessels for the anterolateral thigh flap was related to the length of the pedicle and the thickness of the skin flap. Anatomic variations of the branching p attern of perforators were classified into eight types. Flaps with per forators that arise directly from the profunda femoris artery are diff icult to combine with other free flaps. Because the perforators are ex tremely small and tend to thrombose soon after congestion develops, th ese flaps are difficult to salvage with recirculation surgery. Therefo re, several perforators should be included with the flap, if possible. The descending artery of the lateral circumflex femoral artery was al ways accompanied by two veins with different back-flow strengths. Ther efore, veins for microsurgical anastomosis must be chosen carefully. B ecause it is nourished by several perforators arising from the descend ing artery, the vastus lateralis muscle can be combined with the anter olateral thigh flap. However, splitting the muscle longitudinally with out harvesting its blood supply is complicated because its fibers are oblique. The rectus femoris muscle can also be combined with the anter olateral thigh flap, but its pedicle is short and its origin is very n ear the site of anastomosis. When the anterolateral thigh flap is comb ined with the tensor fasciae latae musculocutaneous flap, the large sk in area of the lateral part of thigh can be transferred to repair the massive defects. The anterolateral thigh flap has many advantages and can be used to reconstruct many types of defect. However, anatomic var iations must be considered if the flap is to be used safely and reliab ly.