1. Department of Orthopedic and Trauma Surgery, University Hospital of Cologne, Cologne, Germany
2. Department of Orthopedic and Trauma Surgery, Marien Krankenhaus gGmbH, Bergisch Gladbach, Germany
3. Department of Radiology, University Hospital of Düsseldorf, Düsseldorf, Germany
4. Department of Spine Surgery, KLINIK am RING, Cologne, Germany