title: Ureteral obstruction: is the full metallic double-pigtail stent the way to go?
abstract: BACKGROUND
  The Resonance metallic ureteral stent (Cook Medical, Bloomington, Indiana, USA) has been introduced for the management of extrinsic-etiology ureteral obstruction for time periods up to 12 mo.
  
  
  OBJECTIVE
  The current study aims to determine short- and medium-term effectiveness of the Resonance stent in malignant and benign ureteral obstruction.
  
  
  METHODS
  In total, 50 patients with extrinsic malignant obstruction (n=25), benign ureteral obstruction (n=18), and previously obstructed mesh metal stents (n=7) were prospectively evaluated.
  
  
  METHODS
  All patients were treated by Resonance stent insertion. Twenty stents were inserted in antegrade fashion, and the remaining stents were inserted in a retrograde approach. No patient dropped out of the study. The follow-up evaluation included biochemical and imaging modalities.
  
  
  METHODS
  We evaluated the technical success rate, stricture patency rate, complications, and the presence and type of encrustation.
  
  
  CONCLUSIONS
  The technical success rate of transversal and stenting of the strictures was 100%. In 19 patients, balloon dilatation was performed prior to stenting. The mean follow-up period was 8.5 mo. The stricture patency rate in patients with extrinsic malignant ureteral obstruction was 100% and in patients with benign ureteral obstruction 44%. Failure of Resonance stents in all cases of obstructed metal stents was observed shortly after the procedure (2-12 d). In nine cases, stent exchange was demanding. Encrustation was present in 12 out of 54 stents.
  
  
  CONCLUSIONS
  The Resonance stent provides safe and sufficient management of malignant extrinsic ureteral obstruction. Resonance stent use in benign disease needs further evaluation, considering the untoward results of the present study.
authors.affiliation: Department of Urology, University of Patras, Patras, Greece. liatsikos@yahoo.com
authors.forename: Evangelos
authors.initials: E
authors.lastname: Liatsikos
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Kallidonis
authors.forename: Iason
authors.initials: I
authors.lastname: Kyriazis
authors.forename: Constantinos
authors.initials: C
authors.lastname: Constantinidis
authors.forename: Kari
authors.initials: K
authors.lastname: Hendlin
authors.forename: Jens-Uwe
authors.initials: JU
authors.lastname: Stolzenburg
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Karnabatidis
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Siablis
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D015607:Stents; D013997:Time Factors; D014517:Ureteral Obstruction / Q000601:surgery*