title: A Comparative in Vitro Study of Power Output Deterioration over Time Between Ho:YAG Laser Fibers from Different Manufacturers as a Function of Deflection and Power Input.
abstract: OBJECTIVE
  To investigate the performance of laser fibers from 6 major manufacturers in vitro and to identify the effect of time and angulations (180° and 0°) on fiber power output.
  
  
  METHODS
  Overall, 36 single-use fibers were used. Each was tested with an energy input of 0.8, 1.4 and 2.0 Joules. A power detector measured power output after 1, 5, 10 and 15 minutes for three 15-minute cycles of continuous use. For the first 2 cycles, the fiber was bent to 180° with the use of a pre fabricated mould. Analysis of the data was performed by ANOVA and Tukey's test when the results were significant amongst groups. Statistical significance was deemed p < 0.05.
  
  
  RESULTS
  No fiber fracture occurred. There was no significant difference in output at 15 minutes of continuous use at 0° and 180°. The reduction in energy output at the 15th minute of continuous use at 180° was not significant for any fiber type or initial input. Only output differences between the fibers proved to be significant (p = 0.001).
  
  
  CONCLUSIONS
  Fiber fracture and decline in performance is not due to deflection and continuous use. Frictional forces that occur between the fiber tip and the stone fragments may be responsible.
authors.affiliation: Locum Consultant Urological Surgeon, Torbay Hospital, South Devon Healthcare NHS Foundation Trust, Torbay, UK.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bourdoumis
authors.affiliation: Christie NHS Foundation Trust, Manchester, UK.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Christopoulos
authors.affiliation: Department of Medical Physics, Royal London Hospital, Barts Health NHS Trust, London.
authors.forename: Nirmal
authors.initials: N
authors.lastname: Raj
authors.affiliation: Barts Health School of Medicine, London, UK.
authors.forename: Artemis
authors.initials: A
authors.lastname: Fedder
authors.affiliation: Sobeh's Vascular & Medical Center Dubai, Dubai, the United Arab Emirates.
authors.forename: Noor
authors.initials: N
authors.lastname: Buchholz
keywords: Holmium laser; Laser treatment; Lithiasis; Ureteroscopy