Abstract: A 17-year-old male patient sustained extensive avulsion injury of the gluteosacral and other regions with large soft tissue defects following traffic accident， complicated by hemorrhagic shock， open fractures of the pelvis and left femur， wound infection， and sciatic nerve exposure， with skin defect involving approximately 20% of total body surface area. Upon admission， an emergency green channel was established and multidisciplinary consultation was conducted. Wound debridement， vacuum sealing drainage， fracture reduction and fixation， and ileostomy were performed. After satisfactory granulation tissue formation was achieved in the wound， a 35 cm×18 cm pedicled anterolateral thigh myocutaneous flap based on the descending branch of the lateral circumflex femoral artery was harvested and transferred in a retrograde manner for reconstruction of the primary defect， with split-thickness skin grafting performed at the donor site. Postoperative survival of both the flap and skin graft was satisfactory. Six-month follow-up examination demonstrated favorable sensory recovery and contour of the flap， with muscle strength graded as 5 and essentially normal function of the affected lower extremity.

Key words: Anterolateral thigh myocutaneous flap, &emsp, Gluteosacral region, &emsp, Soft tissue defects, &emsp, Wound repair