title: [Changes in physical characteristics of endourologic catheters caused by shock waves].
abstract: OBJECTIVE
  To analyze the shock wave effects on double-J stent.
  
  
  METHODS
  Retention strength modifications induced by shock waves were analyzed: a) 60 double-J stents obtained from patients were compared (20 had not been treated by ESWL; 20 had been treated by piezoelectric-ESWL and 20 by electrohydraulic-ESWL; b) the effects of piezoelectric-ESWL were determined in vitro using 36 stress-tested double-J stent segments (Urosoft, C-Flex and silicone) vs. a control group.
  
  
  RESULTS
  The retention strength of the stents from ESWL-treated patients, especially those that had been submitted to piezoelectric-ESWL, was lower than in stents from patients that had not undergone ESWL (p < 0.05). The foregoing has been corroborated by the in vitro findings. The impact frequency causing maximum damage is specific for each material. Microphotographic studies revealed fracture lines on the surfaces of the ESWL-treated stents (Urosoft and C-Flex).
  
  
  CONCLUSIONS
  The foregoing findings may explain the high incidence of double-J stent migration observed in ESWL-treated patients.
authors.affiliation: Servicio de Urología, Hospital Ramón y Cajal, Madrid, España.
authors.forename: F J
authors.initials: FJ
authors.lastname: Burgos Revilla
authors.forename: J C
authors.initials: JC
authors.lastname: Saez Garrido
authors.forename: M
authors.initials: M
authors.lastname: Tellez Martínez-Fornes
authors.forename: E
authors.initials: E
authors.lastname: Martín Martín
authors.forename: J
authors.initials: J
authors.lastname: Vallejo Herrador
mesh_terms: D002404:Catheterization; D008096:Lithotripsy; D014546:Urinary Catheterization / Q000295:instrumentation*
vernacular_title: Modificaciones de las características físicas de los catéteres endourológicos inducidas por la onda de choque.