1. University Hospital Southampton NHS Trust, Southampton SO16 6YD, UK
2. Department of Urology, Comprehensive Cancer Center, Medical University of Vienna, 1090 Vienna, Austria
3. EAU Section of Urolithiasis (EULIS), 6803 AA Arnhem, The Netherlands
4. Urology Unit, School of Urology, Faculty of Medicine, Marche Polytechnic Unviersity, 60121 Ancona, Italy