title: Prospective evaluation of ureteral stent durability in patients with chronic ureteral obstruction.
abstract: OBJECTIVE
  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 hydronephrosis 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.
authors.affiliation: Department of Surgery, Section of Urology, University of Chicago Hospitals, Chicago, Illinois 60611, USA.
authors.forename: Nejd F
authors.initials: NF
authors.lastname: Alsikafi
authors.forename: R Corey
authors.initials: RC
authors.lastname: O'Connor
authors.forename: Dimitri D
authors.initials: DD
authors.lastname: Kuznetsov
authors.forename: Abraham H
authors.initials: AH
authors.lastname: Dachman
authors.forename: Gregory T
authors.initials: GT
authors.lastname: Bales
authors.forename: Glenn S
authors.initials: GS
authors.lastname: Gerber
mesh_terms: D002908:Chronic Disease; D005500:Follow-Up Studies; D006801:Humans; D011446:Prospective Studies; D015607:Stents; D013997:Time Factors; D014517:Ureteral Obstruction / Q000628:therapy*