If there is ureteral stent placed after surgery in stone patients, once it is removed, it is typically thrown into the garbage. With this study, it will be removed and the surface of the stent will be examined for crystals and adherent proteins. The collected samples will be submitted for SELDI analysis and to measure non-protein components. Each patient's serum sample will also be submitted for protein analysis. Other samples will be stored indefinitely until used. The urine, serum, and ureteral stents obtained in this study will be banked at -80C in a locked, secure area.