Anterolateral Thigh Flap in Experimental Rat Models

We have been interested in the article by Tetik Menevse et al, entitled “Expansion of Surviving Skin Paddle of Neurocutaneous Island Flaps in Rats by VEGF.”[1] The authors present a successful experience with a neurocutaneous island flap based on a cutaneous branch arising mainly from the saphenous nerve and sometimes from the epigastric nerve. We congratulate the authors for their results, which, by adding further proof of the role of growth factors in flap survival, will hopefully help accelerate the field toward the use of the vascular endothelial growth factor (VEGF) in human patients. As proposed by Gurunluoglu et al,[2] the authors defined their model as an “anterolateral thigh flap.” Our experience in the dissection of 20 male Sprague-Dawley rats, weighing 300 to 350 g, confirms that the lateral aspect of the thigh in rats is supplied by the terminal branch of the iliolumbar artery and vein. These vessels originate from the abdominal aorta and from the inferior vena cava, respectively; the left one may arise from the common iliac as well.[3] On each side, after crossing the ventral surface of the psoas major muscle, the vascular bundle divides at the level of the quadratus lumborum muscle into an iliac and a lumbar pedicle (Fig. [1]). The lateral cutaneous nerve of the thigh is a collateral branch of the lumbar plexus that pierces the lateral aspect of the psoas major muscle belly to join the iliolumbar vascular bundle just before its main bifurcation. The lateral cutanous nerve of the thigh, together with the inferior divisions of the iliolumbar artery and veins, run in an inferolateral direction as a neurovascular bundle to pierce the muscular abdominal wall over the lateral third of the inguinal ligament and then branch in the lateral aspect of the thigh (Fig. [2]).

Figure 1 Psoas muscle removed and lateral cutaneous nerve of the thigh (white arrow) exposed with its origin from the lumbar plexus. Black arrow, descending branch of the iliolumbar artery.

Figure 2 Left view of the branching pattern of the neurovascular pedicle into the anterolateral aspect (ALT) of the thigh after it pierces the lateral abdominal wall over the lateral third of the inguinal ligament. Fvv,n, femoral vessels and nerve; SEvv,n, superficial epigastric vessels and nerve; dILvv, descending iliolumbar vessels; LCNT, lateral cutaneous nerve of the thigh.

We consider that the model proposed by our colleagues should be finally renamed as the “anteromedial thigh flap” in respect of the cutaneous distribution of the saphenous nerve and its branches on the anterior and medial aspect of the rat's lower extremity, as well as the actual location of the flap on the anteromedial aspect of the thigh; a proper anterolateral thigh flap on experimental rats, here proposed for the first time, can be definitely based on the neurovascular pedicle composed of the lateral cutaneous nerve of the thigh and the terminal cutaneous branch of the iliolumbar pedicle, which we found consistently on each side of our 20-rat sample.

REFERENCES

• 1 Tetik Menevse G, Islamoglu K, Ege Ozgentas H. Expansion of surviving skin paddle of neurocutaneous island flaps in rats by VEGF.  J Reconstr Microsurg. 2007;  23 99-105
• 2 Gurunluoglu R, Bayramicli M, Sonmez A, Numanoglu A. A neurocutaneous island flap model: an experimental study in rats.  Ann Plast Surg. 2000;  44 53-58
• 3 Greene E C. Anatomy of the Rat. New York; Hafner Publishing Co 1935