1. Department of Orthopaedics, Trauma and Reconstructive Surgery, RWTH Aachen University, Germany
2. Department of Orthopedic, Trauma and Plastic Surgery, University Hospital Leipzig, Germany
3. University Center of Orthopedic, Trauma and Plastic Surgery, University Hospital Carl Gustav Carus at TU Dresden, Germany
4. Spinecenter, Schön Klinik Munich Harlaching University, Deutschland
5. Department I of Internal Medicine, Medical Faculty, University Hospital of Cologne, University of Cologne, Germany
6. Department of Orthopaedic Surgery, Klinikum Magdeburg gGmbH, Germany
7. Spine Department, Center for Musculoskeletal Surgery, Charité University Medicine BerlinUniversity, Germany
8. Department of Orthopedic and Trauma Surgery, Medical Faculty, University of Cologne, Germany