This study presents a rare case of extensive tissue loss from the posterior pelvic wall (gluteal, sacral, and perianal region) and from the intrapelvic organs (rectum) following unusual trauma. This patient underwent successful reconstruction by a method that has not been previously described. Rectal wall reconstruction was performed using gracilis muscle transfer, and sacral reconstruction was performed by gluteus maximus muscle island transfer. Three-year follow-up demonstrated a normal life pattern.