Encrusted urinary stents: evaluation and endourologic management.

Ureteral stents and nephrostomy tubes have been used extensively in urology. Attendant to their use are their associated morbidities, such as pain, infection, and encrustation. We review the literature on the subject of the encrusted stents and drainage catheters, discuss the risk factors for encrustation, and describe the endourologic evaluation and management of these encrusted and retained urinary drainage devices. A variety of factors contribute to the rate at which this process occurs, including the material of the stent or catheter, urine composition, and duration of use. The risk of stent encrustation is increased in patients with a history of urolithiasis and with progressively longer indwelling times. Novel stent designs incorporating antimicrobial eluting stents and stents with enzymes to degrade urinary oxalate have shown promise in vitro to minimize stent morbidity. Imaging plays a pivotal role in determining the appropriate surgical management of the encrusted and retained stent. In cases in which encrustation is minimal, extracorporeal shock wave lithotripsy has been used with high success rate. Calcifications along the ureteral component of the stent can be treated with retrograde ureteroscopy and laser lithotripsy while the percutaneous route is the preferred primary approach when stone size is greater than 2 cm and/or if there is associated significant encrustation on the proximal ureteral end of the stent. It is not unusual to need multiple sessions to successfully render the patient stent and stone free, depending on which modalities are used. A computerized tracking system for patients with indwelling ureteral stents has been advocated to reduce the number of "forgotten" stents. Finally, it is of paramount importance that the treating urologist communicates clearly to the patient the presence of any internal urologic stents, the temporary intent of their use, risks with prolonged indwelling times, and the need for appropriate follow-up to avoid complications of encrustation.