1. CISNE Spine Academy, Star Medica, Chihuahua, Mexico
2. Health Services of the State, Department of Epidemiology, Faculty of Medicine and Biomedical Sciences of the Autonomous University of Chihuahua, Chihuahua, Mexico
3. Research Departmet, Faculty of Medicine and Biomedical Sciences of the Autonomous University of Chihuahua, Chihuahua, Mexico
4. Department of Orthopedics, Central Hospital of Chihuahua, Chihuahua, Mexico,