Urologists have long used urinary stents in patients who have - or who are at risk of developing - an obstruction or blockage of the kidney. These rodlike devices are inserted into the ureter to keep the canal open or to help with healing after trauma, surgery or radiotherapy. More recently the use of stents for the prostate and urethra has also become more widespread, despite poor results in first generation models. Constant development has led to the introduction of second generation stents with a variety of designs, materials and coatings. These have gone a long way to counter the...