1 Department of Plastic, Hand, and Reconstructive Surgery, Burn Center, BG-Trauma Center, Tübingen, Germany Institute for Clinical Epidemiology and Applied Biometry, Tübingen, Germany Department of Plastic, Hand, and Reconstructive Surgery, Burn Center, BG-Trauma Center, Eberhard-Karls-University Tübingen, Tübingen, Germany Department for Plastic Surgery, Marienhospital Stuttgart, Stuttgart, Germany.