[1] Justus Liebig Univ Giessen, Dept Urol Pediat Urol & Androl, Giessen, Germany
[2] Univ Bern, Bern Univ Hosp, Dept Urol, Inselspital, Bern, Switzerland
[3] Univ Med Ctr RWTH Aachen, Dept Urol & Pediat Urol, Aachen, Germany
[4] Martin Luther Univ Halle Wittenberg, Dept Urol & Kidney Transplantat, Halle, Germany
[5] Univ Basel, Ctr Biomech & Calorimetry, Merian Iselin Klin, Alta Uro AG, Basel, Switzerland
[6] Freeman Rd Hosp, Newcastle Upon Tyne, England