1. Spine Surgery Unit 1, Bordeaux University Pellegrin Hospital, Bordeaux, France;
2. Department of Orthopedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan;
3. ELSAN, Polyclinique Jean Villar, Bruges, France;
4. Spine Surgery Unit, Vall d’Hebron Hospital, Barcelona, Spain;
5. Orthopedic and Spinal Surgery Department, Kingdom Hospital, Riyadh, Saudi Arabia;
6. Spine Surgery Unit, Hospital Universitario La Paz, Madrid, Spain;
7. Spine Center, Schulthess Klinik, Zurich, Switzerland;
8. Ankara Spine Center, Ankara, Turkey; and
9. Comprehensive Spine Center, Acibadem Maslak Hospital, Istanbul, Turkey