title: Initial experience with the resonance metallic stent for antegrade ureteric stenting.
abstract: OBJECTIVE
  We describe our initial experience with a new metallic ureteric stent which has been designed to provide long-term urinary drainage in patients with malignant ureteric strictures. The aim is to achieve longer primary patency rates than conventional polyurethane ureteric stents, where encrustation and compression by malignant masses limit primary patency. The Resonance metallic double-pigtail ureteric stent (Cook, Ireland) is constructed from coiled wire spirals of a corrosion-resistant alloy designed to minimize tissue in-growth and resist encrustation, and the manufacturer recommends interval stent change at 12 months.
  
  
  METHODS
  Seventeen Resonance stents were inserted via an antegrade approach into 15 patients between December 2004 and March 2006. The causes of ureteric obstruction were malignancies of the bladder (n = 4), colon (n = 3), gynecologic (n = 5), and others (n = 3).
  
  
  RESULTS
  One patient had the stent changed after 12 months, and 3 patients had their stents changed at 6 months. These stents were draining adequately with minimal encrustation. Four patients are still alive with functioning stents in situ for 2-10 months. Seven patients died with functioning stents in place (follow-up periods of 1 week to 8 months). Three stents failed from the outset due to bulky pelvic malignancy resulting in high intravesical pressure, as occurs with conventional plastic stents.
  
  
  CONCLUSIONS
  Our initial experience with the Resonance metallic ureteric stent indicates that it may provide adequate long-term urinary drainage (up to 12 months) in patients with malignant ureteric obstruction but without significantly bulky pelvic disease. This obviates the need for regular stent changes and would offer significant benefit for these patients with limited life expectancy.
authors.affiliation: Department of Radiology, St. James's University Hospital, Beckett Street, Leeds, LS9 7TF, UK. Tze.Wah@leedsth.nhs.uk
authors.forename: Tze M
authors.initials: TM
authors.lastname: Wah
authors.forename: Henry C
authors.initials: HC
authors.lastname: Irving
authors.forename: Jon
authors.initials: J
authors.lastname: Cartledge
mesh_terms: D000328:Adult; D000368:Aged; D000497:Alloys; D020878:Device Removal; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010386:Pelvic Neoplasms / Q000150:complications*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D015607:Stents; D014517:Ureteral Obstruction / Q000000981:diagnostic imaging / Q000628:therapy*; D014567:Urography
chemical_list: D000497:Alloys; C035402:MP35N alloy