1. The Warren Alpert Medical School of Brown University, Providence, Rhode Island;
2. Center for Spine Health, and
3. Case Western Reserve University School of Medicine;
4. Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, Ohio;
5. NeuroSpine Surgery Research Group, Prince of Wales Private Hospital, Sydney, Australia; and
6. University of New South Wales, Sydney, Australia
7. Departments of Neurosurgery and
8. Orthopaedic Surgery, Cleveland Clinic;