1. Spine Group, Irmandade da Santa Casa de Misericórdia de São Paulo Medical School and Hospitals, São Paulo, Brazil
2. Spine Group, Clínica Palermo (Cirugía Columna), Bogotá D.C., Colombia
3. Spine Surgery Division, Instituto do Câncer do Estado de São Paulo, Brazil
4. Spine Group, Department of Orthopedics and Traumatology, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
5. Spine Surgery Division, Neurological Institute of Curitiba, Curitiba, Brazil
6. Spine Division, Orthopaedics and Traumatology Institute, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil