title: [Plasma-deposited carbon coating on urological indwelling catheters: Preventing formation of encrustations and consecutive complications].
abstract: BACKGROUND
  Any material placed in the urinary tract is susceptible to the formation of encrustations of crystalline bacterial biofilms. These biofilms cause severe complications in some cases. The strategies used so far for reduction of these complications by surface modifications of the implant material failed to show the expected results.
  
  
  METHODS
  In this study, we investigated amorphous carbon coatings (a-C:H) for their ability to effectively reduce or to repress the progressive formation of infection-enhancing crystalline biofilms as new functional surface coatings. In nine patients suffering for several years from stenting, a-C:H-coated ureteral stents were tested in treatment attempts. The current replacement intervals amounted to a mean of 77 days; the principle cause for early replacement was massive stent encrustations associated with symptomatic urinary tract infections.
  
  
  RESULTS
  In total, 20 coated ureteral stents were tested spanning indwelling times between 3 and 4 months. No stent-related complications occurred. In all cases extraordinarily facile handling, less pain during replacement, and markedly increased tolerance were observed. Symptomatic urinary tract infections were reduced by more than 50%. The stents remained virtually free of encrustations.
  
  
  CONCLUSIONS
  a-C:H coatings are a novel strategy leading to an enhancement of long-term applicability of ureteral stents and catheters and to improved patient comfort.
authors.affiliation: Abteilung für Experimentelle Urologie, Klinik und Poliklinik für Urologie, Universitätsklinikum, Sigmund-Freud-Strasse 25, 53105, Bonn. norbert.laube@ukb.uni-bonn.de
authors.forename: N
authors.initials: N
authors.lastname: Laube
authors.forename: J
authors.initials: J
authors.lastname: Bradenahl
authors.forename: A
authors.initials: A
authors.lastname: Meissner
authors.forename: J
authors.initials: J
authors.lastname: V Rappard
authors.forename: L
authors.initials: L
authors.lastname: Kleinen
authors.forename: S C
authors.initials: SC
authors.lastname: Müller
mesh_terms: D000328:Adult; D000368:Aged; D018441:Biofilms / Q000254:growth & development*; D002244:Carbon; D020099:Coated Materials, Biocompatible; D003460:Crystallization; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017616:Magnesium Compounds; D008297:Male; D008875:Middle Aged; D010710:Phosphates; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012307:Risk Factors; D015607:Stents / Q000382:microbiology; D000069877:Struvite; D014517:Ureteral Obstruction / Q000209:etiology / Q000382:microbiology / Q000628:therapy*; D014552:Urinary Tract Infections / Q000382:microbiology / Q000517:prevention & control
chemical_list: D020099:Coated Materials, Biocompatible; D017616:Magnesium Compounds; D010710:Phosphates; D002244:Carbon; D000069877:Struvite