title: The use of a ureteral access sheath does not improve stone-free rate after ureteroscopy for upper urinary tract stones.
abstract: OBJECTIVE
  To evaluate the impact of a ureteral access sheath (UAS) on stone-free (SF) rate after flexible ureteroscopy for upper urinary tract stones.
  
  
  METHODS
  We retrospectively reviewed 280 patients who underwent flexible ureteroscopy (URS) for upper urinary tract stone between 2009 and 2012. Patients were divided into two groups based on whether a UAS was used (n = 157) or not (n = 123). SF rate was evaluated at one and three months after surgery by abdominal imaging. Quantitative and qualitative variables were compared with Student's t test and χ2 test, respectively. A logistic regression model was used to determine the predictive factors of SF status.
  
  
  RESULTS
  Stone size was similar in both groups (15.1 vs. 13.7 mm, p = 0.21). SF rates at one and 3 months were comparable in UAS and non-UAS groups (76 vs. 78% and 86 vs. 87%, p = 0.88 and 0.89, respectively). Complication rates were similar in both groups (12.7 vs. 12.1%, p = 0.78). In multivariable analysis, stone size was the only predictive factor of SF rate (p = 0.016).
  
  
  CONCLUSIONS
  The routine use of a UAS did not improve SF rate in patients undergoing flexible URS for upper urinary tract calculi.
authors.affiliation: Department of Urology, Pontchaillou University Hospital, University of Rennes 1, 35000, 2 Rue Henri le Guilloux, Rennes, France, gberquet@hotmail.fr.
authors.forename: Gaetan
authors.initials: G
authors.lastname: Berquet
authors.forename: Paul
authors.initials: P
authors.lastname: Prunel
authors.forename: Grégory
authors.initials: G
authors.lastname: Verhoest
authors.forename: Romain
authors.initials: R
authors.lastname: Mathieu
authors.forename: Karim
authors.initials: K
authors.lastname: Bensalah
mesh_terms: D000328:Adult; D000368:Aged; D004864:Equipment and Supplies; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D016896:Treatment Outcome; D018666:Ureteroscopy / Q000295:instrumentation* / Q000379:methods*; D014545:Urinary Calculi / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery*