[Clinical application effects of the "three-source and four-line method" in the design and harvest of anterolateral lower leg perforator flaps].

Objective: To explore the clinical application effects of the "three-source and four-line method" in the design and harvest of anterolateral lower leg perforator flaps. Methods: This study was a retrospective study of case series. From August 2023 to July 2024, the patients with hand or foot wounds who met the inclusion criteria were admitted to Suzhou Ruihua Orthopedic Hospital, including 24 patients from the Department of Hand Surgery and 6 patients from the Department of Foot and Ankle Surgery. There were 22 males and 8 females, aged 18 to 58 years. After debridement, the single wound area ranged from 2.0 cm×1.5 cm to 15.0 cm×4.5 cm. By applying the "three-source and four-line method", the line connecting the fibular head and the tip of the lateral malleolus was defined as Line C, representing the body surface marking line of the fibula; Line B was defined as Line C shifted 1.5 cm anteriorly, representing the axis of the superficial peroneal artery perforator flap; Line A was defined as Line C shifted 3.0 cm anteriorly, representing the axis of the anterior tibial artery perforator flap; Line D was defined as Line C shifted 1.5 cm posteriorly, representing the axis of the peroneal artery perforator flap. Then the color Doppler ultrasound detector was employed to identify perforators from the three vascular origins along Lines A, B, and D. Accordingly, anterolateral lower leg perforator flaps were designed and harvested to repair the wounds. A total of 35 flaps were harvested, with the single flap area ranging from 2.5 cm×2.0 cm to 16.0 cm×5.0 cm. The donor site wounds were closed by direct suturing. During surgery, the total number of actually used perforators, as well as the number, caliber, vascular pedicle length of perforators from different sources, and the vertical distances from the skin entry points of the perforators to their corresponding axes were recorded. After surgery, the flap survival was observed. During follow-up, the color, texture, and appearance of the flaps and the scar condition of donor sites were recorded. At the final follow-up, the flap repair outcome was evaluated using the flap comprehensive rating scale, and the excellent and good ratio of flap repair outcome was calculated. Results: During surgery, a total of 38 perforators were actually used. Among them, 6 perforators originated from the anterior tibial artery, with a mean caliber of 0.47 mm, a mean vascular pedicle length of 4.33 cm, and a mean vertical distance from the skin entry point of the perforator to the Line A of 0.48 cm. Twenty perforators originated from the superficial peroneal artery, with a mean caliber of 0.51 mm, a mean vascular pedicle length of 5.25 cm, and a mean vertical distance from the skin entry point of the perforator to the Line B of 0.54 cm. Twelve perforators originated from the peroneal artery, with a mean caliber of 0.72 mm, a mean vascular pedicle length of 4.13 cm, and a mean vertical distance from the skin entry point of the perforator to the Line D of 0.43 cm. After surgery, all flaps survived smoothly. Follow up for 6 to 15 months showed the flaps exhibited favorable color, soft texture, and no obvious bulkiness; only linear scars were left at the donor sites. At the final follow-up, the scores of flap comprehensive rating scale ranged from 82 to 94 and the excellent and good ratio of flap repair outcome was 100% (35/35). Conclusions: The "three-source and four-line method" has the advantages of simple operation and accurate perforator localization. It is helpful for flexible preoperative design and safe intraoperative harvest of the anterolateral lower leg perforator flaps with high clinical application value.