A reliable parameter for primary closure of the free anterolateral thigh flap donor site.

Background: Primary closure of the donor site after flap harvest is key to achieving a satisfactory result. The authors investigated the width of the harvested anterolateral thigh flap allowing primary closure of the donor site.

Methods: Sixty-five consecutive patients undergoing reconstructive procedures using anterolateral thigh flaps were divided into two groups: group A, primary closure of the donor site; and group B, donor site covered with split-thickness skin graft. Maximum flap width and thigh circumference were measured at the midpoint of the line connecting the lateral superior margin of the patella and the anterior superior iliac spine. The maximum flap width-to-thigh circumference ratio was calculated. Patients' body mass index and age were recorded. The outcome was evaluated by the surgeon.

Results: Primary closure of the donor site was possible in 56 patients (86 percent), and in nine patients (14 percent) a split-thickness skin graft was necessary. All of the donor sites were closed primarily when the flap width was less than 16 percent of the thigh circumference. There was a significant correlation between body mass index and the ratio (p<0.001, r=-0.573) and between patient age and the ratio (p=0.033, r=0.267). Muscle herniation was significantly higher in group B (p=0.029).

Conclusions: The flap width-to-thigh circumference ratio is a reliable parameter for preoperative planning of primary closure of the anterolateral thigh flap donor site. Primary closure can be achieved if the flap width-to-thigh circumference ratio is less than 16 percent. The patient's body mass index and age have to be taken into consideration.