PROSPECTIVE EVALUATION OF URETERAL STENT DURABILITY IN PATIENTS WITH CHRONIC URETERAL OBSTRUCTION NEJD F. ALSIKAFI, R. COREY O’CONNOR, DIMITRI D. KUZNETSOV, ABRAHAM H. DACHMAN, GREGORY T. BALES, AND GLENN S. GERBER ABSTRACT Objectives. To prospectively evaluate the durability of ureteral stents in patients with chronic ureteral obstruction. Methods. Twenty-nine renal units from 22 patients with known chronic ureteral obstruction treated with indwelling ureteral stents were studied at 3, 6, 9, and 12 months after initial stent placement (7 to 8F Percuflex) by abdominal x-ray, serum creatinine, and renal and bladder ultrasonography. Renal ultrasound scans were performed by a single senior radiologist with specific attention paid to any increase in hydro- nephrosis and to the presence of ureteral jets. The stent was changed when calcifications were seen along the stent on abdominal x-ray, if an increase in serum creatinine occurred, or if any increase in hydronephrosis or absence of ureteral jets was seen on ultrasonography. In addition, the stents were changed if new-onset flank pain and/or pyelonephritis developed. If none of the above occurred, the stents were changed after 12 months. Results. Two patients died of metastatic cancer, leaving 25 renal units available for follow-up. The mean and median time to stent change were 6 months. At 3, 6, 9, and 12 months, the number of renal units that did not meet the criteria warranting stent change was 18 (72%), 12 (48%), 6 (24%), and 2 (8%), respectively. Only 2 (8%) of 25 renal units did not meet any exclusion criteria at 12 months. The most common reasons for requiring the stent to be changed were new-onset flank pain in 8 (35%), an increase in serum creatinine in 7 (30%), and new-onset or increased hydronephrosis in 7 (30%). No criteria were useful in predicting how long stents could be maintained in an individual patient. Conclusions. The stents were maintained for more than 6 months in 12 (48%) of 25 renal units. However, very few patients were able to maintain chronic ureteral stents for 12 months without requiring stent change based on our criteria. UROLOGY 59: 847–850, 2002. © 2002, Elsevier Science Inc. P atients with chronic hydronephrosis are often treated with indwelling ureteral stents that are usually changed every 3 to 6 months. The fre- quency of stent changes is a source of patient bother and subjects patients to an increased risk of anesthetic and/or iatrogenic complications. Fur- thermore, many patients endure significant dis- comfort due to urinary tract instrumentation. These factors undoubtedly have a negative impact on the patient’s quality of life. In an effort to assess the durability of recently produced stents, human and animal studies have been performed that suggest that ureteral stents can remain patent and be safely left in situ for 9 to 24 months in certain subsets of patients. 1–3 How- ever, it is unclear from these studies whether pa- tients can withstand less frequent stent changes without adverse consequences such as encrusta- tion, infection, obstruction, and loss of renal func- tion. 4,5 Additionally, calcifications can make stent removal difficult and in some cases may necessitate auxiliary procedures such as extracorporeal shock wave lithotripsy or other procedures to be per- formed. 6 It is also unclear what factors, if any, can be used to predict reliably the frequency that stent changes will be needed in an individual patient. In the present study, we prospectively evaluated From the Departments of Surgery, Section of Urology, and Radi- ology, University of Chicago Hospitals, Chicago, Illinois Reprint requests: Nejd F. Alsikafi, M.D., Department of Sur- gery, Section of Urology, MC6038, University of Chicago Hospi- tals, 5841 South Maryland Avenue, Chicago, IL 60611 Submitted: November 8, 2001, accepted (with revisions): Jan- uary 28, 2002 ADULT UROLOGY © 2002, ELSEVIER SCIENCE INC. 0090-4295/02/$22.00 ALL RIGHTS RESERVED PII S0090-4295(02)01599-6 847