1. Postgraduation Program in Health Sciences, University of Caxias do Sul, Caxias do Sul, Brazil;
2. Department of Neurosurgery, University of Caxias do Sul, Caxias do Sul, Brazil;
3. Cajuru University Hospital, Spine Surgery Unit, Curitiba, Brazil;
4. São Vicente de Paulo Hospital, Neurosurgery Unit, Passo Fundo, Brazil;
5. Hospital Universitario Fundación Favaloro, Spine Surgery, Buenos Aires, Argentina;
6. Department of Traumatology—Spine Unit, Clínica Alemana, Santiago, Chile;
7. Department of Neurosurgery—Spine Surgery, Hospital de Clínicas José de San Martin—University of Buenos Aires, Buenos Aires, Argentina;
8. Department of Orthopedics and Traumatology, Hospital de Especialidades, Guadalajara, Mexico;
9. Instituto Tecnológico y de Estudios Superiores de Monterrey, Campus Guadalajara, Guadalajara, Jalisco, México;
10. Spine Surgery Department, Instituto Nacional de Rehabilitación, Mexico City, Mexico;
11. Department of Orthopaedics—Spine Surgery, Hospital Dr Diego Thompsonn, Bueno Aires, Argentina;
12. Department of Neurosurgery, Professor and Chairman, Lahey Hospital and Medical Center—Tufts University School of Medicine, Burlington, USA