[1] Univ Med Ctr Utrecht, Dept Urol, NL-3508 GA Utrecht, Netherlands
[2] Guys & St Thomas NHS Fdn Trust, Dept Obstet & Gynaecol, London, England
[3] Maastricht Univ, Med Ctr, Dept Urol, Maastricht, Netherlands
[4] Univ Hosp Balgrist, Dept Neurourol, Zurich, Switzerland