1 Department of Radiology, Fundación Instituto Valenciano de Oncología, 46009 Valencia, Spain; Spanish Back Pain Research Network, HLA-Moncloa University Hospital, Valladolid, Madrid, Spain. Electronic address: aranae@ext.uv.es.
2 Spanish Back Pain Research Network, HLA-Moncloa University Hospital, Valladolid, Madrid, Spain; Kovacs Back Pain Unit, HLA-Moncloa University Hospital, Valladolid, Madrid, Spain.