Anatomical Relations of the Perforators from the Descending Lateral Femoral Circumflex Artery and Vastus Lateralis Motor Nerve Branches

Abstract

Background: The anterolateral thigh (ALT) flap, which is nourished by perforators from the descending branch of the lateral femoral circumflex artery (P), is one of the most commonly used flaps in soft tissue reconstruction. With the growing use of ALT flaps, attention toward donor-site morbidity has increased in recent years. Damage to the motor nerve branches of the vastus lateralis muscle (N) is one of the causes of donor-site morbidity, particularly muscle weakness. This study investigated the anatomical locations of the P and N in fresh-frozen cadaveric specimens. Methods: This study included 43 cadaver limbs. A silicone rubber compound (30 mL) was injected into the femoral artery to visualize the vessel. The locations of the P and motor points of N were measured to assess the risk of N injury during ALT flap harvesting. Results: There were one to six (mean, 2.7) P and two to seven (mean, 4) N. When the two most proximal perforators were used for flap harvesting, an average of 1.5 motor nerve branches (42%) was damaged because transection of the motor nerve branches was required for flap harvesting. In 33% of the limbs, only one motor nerve branch remained after the flap harvest. However, there were no cases where all motor nerve branches were severed. Conclusion: When an ALT flap with two perforators is harvested, weakness of the vastus lateralis muscle may occur in cases with a small number of motor nerve branches.