1. Department of Orthopaedic Surgery and Traumatology Klinikum Esslingen Esslingen am Neckar Germany
2. Laboratory for Applied and Clinical Anatomy, Department of Anatomy, Histology and Embriology Semmelweis University Budapest Hungary
3. Clinical Anatomy Tübingen University of Tübingen Tübingen Germany
4. Department of Neurosurgery Leeds Teaching Hospitals NHS Trust Leeds United Kingdom
5. Oklahoma Heart Hospital Oklahoma City Oklahoma USA
6. Georgia Spine & Neurosurgery Center Atlanta Georgia USA
7. The Spine Clinic of Oklahoma City Oklahoma City Oklahoma USA