Anatomic study of the femur-vastus intermedius muscle-anterolateral thigh osteomyocutaneous free flap.

[INTRODUCTION] Resection of head and neck malignancy usually causes facial defects and esthetic deformities. Among the wide range of free flaps available for reconstruction, a novel chimeric free flap-the femur-vastus intermedius muscle-anterolateral thigh osteomyocutaneous free flap (FVATLO flap)-has been demonstrated for clinical use. In this study, we illustrate the anatomy and harvest of the FVATLO flap.

[METHODS] Eighteen fresh cadavers without damage to either thigh were recruited for dissection. Blood supply to the vastus intermedius muscle and femur were traced and recorded. The diameter, circumference of the middle part of the femur, and thickness of the femoral cortex were measured.

[RESULTS] The major blood supply to the vastus intermedius muscle showed two patterns of origin. The first arising from the descending branch of the lateral circumflex femoral artery (LCFA-db) accounts for 78% of the cases (28/36), and the second arising from the transverse branch of the lateral circumflex femoral artery (LCFA-tb) accounts for 22% (8/36). Blood supply to the femur consists of two major sources: one from branches penetrating through the nutrient foramen on the posteromedial surface of the femur to the medullary cavity, and the other from the periosteum branches spreading over on the femoral surface. No visible branch from the vastus intermedius muscle to the underlying periosteum was found. The mean diameter, femoral circumference, and mean cortical thickness were 26.30 mm, 85.58 mm, and 6.85 mm, respectively.

[CONCLUSION] Considering that there is only one injured donor site, the FVALTO flap is an alternative chimeric flap for cases with a large amount of soft tissue loss together with small bony defects.