1. Spine Department, University Hospital, Strasbourg, France
2. Parisian Institute, Geoffroy Saint-Hilaire Clinic, Paris, France
3. Neuro-Surgery Department, University Hospital, Dijon, France
4. Orthopaedic Department, Back Aquitain Center, Mérignac, France
5. Neuro-Surgery Department, Clinic of Parc, St-Priest-en-Jarez, France