Christopher R Chapple1, Peter Albers2, John Denstedt3. 1. Department of Urology, Royal Hallamshire Hospital, Sheffield, UK. Electronic address: c.r.chapple@shef.ac.uk. 2. Department of Urology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany. 3. Department of Surgery, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada.