[Clinical application and Zunyi Classification of free anterolateral thigh chimeric flaps]

Objective: To summarize the clinical application and Zunyi Classification of free anterolateral thigh chimeric flaps. Methods: This study was a retrospective observational study. From June 2021 to June 2024, 200 patients who underwent free anterolateral thigh chimeric flap transplantation and met the inclusion criteria were admitted to the Affiliated Hospital of Zunyi Medical University, including 106 males and 94 females, aged 3 to 77 years. The wound types included mechanical trauma wounds in 175 cases, chronic wounds in 18 cases, and other wounds (postoperative infection, burns, etc.) in 7 cases. The wounds were located distal to the ankle or wrist joints in 171 cases; between the knee and above the ankle or between the elbow and above the wrist in 24 cases; and between the sacrum and above the knee, or between the shoulder and above the elbow in 5 cases. The application of free anterolateral thigh chimeric flaps with different tissue components for repairing various defects was analyzed to sum up the classification of free anterolateral thigh chimeric flaps. Results: The Zunyi Classification of free anterolateral thigh chimeric flaps was successfully established, including 68 cases of type Ⅰ, 81 cases of type Ⅱ, 23 cases of type Ⅲ, and 28 cases of type Ⅳ. type Ⅰ chimeric flaps were composed of 1 type of tissue, such as bilobed, trilobed, or other lobed flaps, which were suitable for patients requiring repair of simple skin defects. Type Ⅱ chimeric flaps were composed of 2 types of tissue and were further classified into subtypes Ⅱa and Ⅱb based on the presence or absence of lobed skin. They were suitable for patients requiring repair of skin defects along with reconstructing the function of another tissue type. Type Ⅲ chimeric flaps were composed of 3 or more types of tissue and were further classified into subtypes Ⅲa and Ⅲb based on the presence or absence of lobed skin. They were suitable for patients requiring repair of skin defects along with reconstructing the function of 2 or more types of tissue. Type Ⅳ chimeric flaps required microsurgical construction via vascular anastomosis. These flaps could be flexibly designed with customized tissue combinations to meet specific wound reconstruction needs. They were indicated for patients with extensive skin defects, specialized tissue defects, or anatomical regions where reconstruction cannot be achieved by a single anterolateral thigh donor site, necessitating harvest of additional donor tissues. Conclusions: The Zunyi Classification of free anterolateral thigh chimeric flaps based on tissue sources of chimeric flaps emphasizes the functional requirements of recipient sites, which helps guide the repair of various complex wounds and facilitates clinical promotion.