To prospectively summary the piercing-out position, direction, length and piercing-in position of perforator, and investigate the feasibility of preoperative design and optimization of the anterolateral thigh flap and its clinical application.

All 58 cases of anterolateral thigh flaps were designed and taken from the lateral thigh area from January, 2014 to January, 2016. Portable Doppler ultrasound was used before an operation to detect the piercing-out position (point P) of perforators. The direction and length (lower subcutaneous segment of perforators) of perforators after leaving piercing-out position were observed during the operation. And the piercing-in positions (point P') on superficial fascia and the dermis were observed. Based on this, we added line B (anterior superior spine-lateral femoral epicondyle) and line C (anterior superior spine-the middle point of superior border of patella) in the lateral and anterior side of original ilium-patella line in the thigh (line A) , respectively.

All perforators found in 58 cases before and during the operations were located on line A or between line A and line B. No perforators were found between line A and line C. Perforators walked toward the anterior medial side after leaving the muscle membrane. The perforator vascular subcutaneous segment (distance between point P and point P') was (2.02±0.23) cm. There was rectus muscle branch in the descending branch of lateral femoral circumflex artery, while no rectus muscle cutaneous branch was seen. 20 cases were designed by one-line method, 12 cases were designed by two-line method, while 26 cases were designed by three-line method.

Advanced three-line method is beneficial to detect of the perforators on the anterior thigh lateral region and to reduce the intraoperative injury perforator vessels at the puncture point. Clinical application of the anterior lateral thigh flap is simple and reliable.

Anterolateral thigh flap; Perforator; Detection; Repair; Reconstructive