title: Externally coated ureteral metallic stents: an unfavorable clinical experience.
abstract: OBJECTIVE
  The purpose of the present study was to evaluate the use of externally coated stents in patients with malignant ureteral obstruction.
  
  
  METHODS
  We have prospectively evaluated 16 patients, 10 men and 6 women, with malignant ureteral obstruction treated successfully by placement of Passager metal stents (Boston Scientific, Natick, MA, USA) bypassing the stricture. Mean patient age was 65.6 years (range 62-78 years). Ureteral patency was confirmed 24 and 48 hours by injection of contrast material through the nephrostomy tube, and after patency confirmation the nephrostomy catheter was removed.
  
  
  RESULTS
  All stents were positioned successfully, and the postoperative course was uneventful. In 13 cases (81.2%) the prostheses finally migrated into the bladder hindering overall ureteral patency (mean time of migration: 1.5 months). Patency was achieved in the remaining ureters (n=3), during the follow-up period (mean: 8 months, range 6-16 months), without any need for further intervention.
  
  
  CONCLUSIONS
  The inappropriate anchorage and the increased ureteral peristalsis are the main causes of migration towards the bladder, thus, minimizing the usefulness of this stent for the treatment of ureteral strictures.
authors.affiliation: Department of Urology, University of Patras Medical School, University Hospital, Rio, 26 500, Patras, Greece. gbarbal@med.upatras.gr
authors.forename: George A
authors.initials: GA
authors.lastname: Barbalias
authors.forename: Evangelos N
authors.initials: EN
authors.lastname: Liatsikos
authors.forename: Christina
authors.initials: C
authors.lastname: Kalogeropoulou
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Karnabatidis
authors.forename: Petros
authors.initials: P
authors.lastname: Zabakis
authors.forename: Anastasios
authors.initials: A
authors.lastname: Athanasopoulos
authors.forename: Petros
authors.initials: P
authors.lastname: Perimenis
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Siablis
mesh_terms: D000368:Aged; D020099:Coated Materials, Biocompatible / Q000009:adverse effects; D005260:Female; D005548:Foreign-Body Migration; D005833:Genital Neoplasms, Female / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000150:complications; D012004:Rectal Neoplasms / Q000150:complications; D015607:Stents / Q000009:adverse effects*; D016896:Treatment Outcome; D014517:Ureteral Obstruction / Q000209:etiology / Q000628:therapy*
chemical_list: D020099:Coated Materials, Biocompatible