1. Urology Department, University Hospital of Salamanca, 37007 Salamanca, Spain
2. Department of Surgery, University of Salamanca, 37007 Salamanca, Spain
3. Urology Department, Puerta del Mar University Hospital in Cádiz, 11009 Cádiz, Spain
4. Nephrology Department, University Hospital of Salamanca, 37007 Salamanca, Spain
5. Urology Unit, Surgery Department, University of La Laguna, San Cristóbal de La Laguna, 38200 Santa Cruz of Tenerife, Spain