title: Laser Fiber and Flexible Ureterorenoscopy: The Safety Distance Concept.
abstract: The costs of flexible ureterorenoscopes (fURSs) and their repair oblige the surgeon to know the proper handling of instruments. There is a lack of evidence in the literature about the safety distance that the laser fiber should have once out from the ureterorenoscope to avoid instrumental damages.
  
  
  
  We performed an in vitro observational study. Seven fURSs were tested. The distance from the laser fiber tip and the fURS camera was measured at the first appearance on the endoscopic screen and when the fiber was reaching one-fourth of the screen. Second, to evaluate the impact of the holmium laser bubble according to different fiber distances, an assessment of the size and shape of the bubble created at the tip of the fiber with the laser activated was done, recording the images with a high-speed camera.
  
  
  
  The first appearance on the screen of the laser tip is different in different ureterorenoscopes. In all the ureterorenoscopes, we observed that when the laser fiber was at ¼ of the screen, the bubble was never touching the fURS tip.
  
  
  
  Even if there is a big limitation of this study due to the impossibility to measure and to evaluate the damage of the fURS tip surface, we observed that when the laser fiber tip reaches ¼ of the screen, the bubble generated by laser activation is never rebounding on the camera of the ureterorenoscope, preserving it from laser damages. We can define this position as the safety distance.
authors.affiliation: 1 Department of Urology, Hôpital Tenon, Université Pierre et Marie Curie-Paris VI 4 rue de la Chine , Paris, France .|2 Department of Urology, Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano , Milano, Italy .
authors.forename: Michele
authors.initials: M
authors.lastname: Talso
authors.affiliation: 1 Department of Urology, Hôpital Tenon, Université Pierre et Marie Curie-Paris VI 4 rue de la Chine , Paris, France .|3 Fundacion Puigvert, Department of Urology, Universitat Autonoma de Barcelona, Barcelona, Spain .
authors.forename: Esteban
authors.initials: E
authors.lastname: Emiliani
authors.affiliation: 1 Department of Urology, Hôpital Tenon, Université Pierre et Marie Curie-Paris VI 4 rue de la Chine , Paris, France .|4 Laboratoire PIMM-UMR 8006 Ecole Nationale des Arts et Métiers-131 Boulevard de l'Hôpital , Paris, France .
authors.forename: Mattieu
authors.initials: M
authors.lastname: Haddad
authors.affiliation: 4 Laboratoire PIMM-UMR 8006 Ecole Nationale des Arts et Métiers-131 Boulevard de l'Hôpital , Paris, France .
authors.forename: Laurent
authors.initials: L
authors.lastname: Berthe
authors.affiliation: 1 Department of Urology, Hôpital Tenon, Université Pierre et Marie Curie-Paris VI 4 rue de la Chine , Paris, France .
authors.forename: Mohammed
authors.initials: M
authors.lastname: Baghdadi
authors.affiliation: 2 Department of Urology, Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico, Università degli Studi di Milano , Milano, Italy .
authors.forename: Emanuele
authors.initials: E
authors.lastname: Montanari
authors.affiliation: 1 Department of Urology, Hôpital Tenon, Université Pierre et Marie Curie-Paris VI 4 rue de la Chine , Paris, France .
authors.forename: Olivier
authors.initials: O
authors.lastname: Traxer
mesh_terms: D004867:Equipment Design; D006801:Humans; D020702:Hysteroscopes; D007668:Kidney; D053844:Lasers, Solid-State; D017602:Lithotripsy, Laser / Q000295:instrumentation* / Q000379:methods; D061214:Patient Safety; D018666:Ureteroscopy / Q000295:instrumentation* / Q000379:methods
keywords: cost; flexible ureterorenoscopy; holmium laser; laser fiber; safety; stone