<qa>  What is one of the most common procedures performed within urology?Ureteral stent placement is one of the most common procedures performed within urology. The stents are generally placed for relief of obstruction or to prevent obstruction following a urological procedure. Most patients with ureteral stents will eventually form stent encrustations. However, patients form these encrustations at dramatically different degrees and rates ranging from no encrustation at 1 year of stenting to severe encrustation in just a few weeks. The purpose of this study is to determine if the degree of encrustation on a stent for any given patient can be predicted based on 24 hour urine parameters prior to stent placement, with the stent in place and after stent removal. 