title: Temporal Trends and Treatment Outcomes of Flexible Ureteroscopy for Lower Pole Stones in a Tertiary Referral Stone Center.
abstract: BACKGROUND
  To evaluate trends in efficacy and safety of flexible ureteroscopy (fURS) for the treatment of lower pole stones (LPS) over a 6-year period and to compare the annual outcomes after one fURS procedure retrospectively.
  
  
  METHODS
  Four hundred nine patients were treated for pure LPS. An analysis of the annual outcomes regarding patient characteristics, operative parameters, stone-free rates (SFRs), and complication rates (CRs) was performed. The SFR was stratified according to stone size and number of stones per patient. Patient data are expressed as mean±standard deviation.
  
  
  RESULTS
  There were no annual differences regarding age, body-mass index, stone size (7.09±4.31 mm), number of stones per patient (1.66±2.86), operative time (52.93±33.58 minutes), use of postoperative stents (59.2%), and the Ho:YAG laser lithotripsy rate (49.4%) during the 6-year period. Total primary SFR (annual range) of 97.6% (88.2%-100%), 89.1% (82.9%-96.3%), 71% (60%-78.6%) for urinary calculi <5 mm (3.43±0.78 mm), 5-9 mm (6.69±1.34 mm), and ≥10 mm (13.09±6.02 mm) could be demonstrated over the 6-year period. The total SFR differed significantly between urinary calculi <5 mm, 5-9 mm, and those ≥10 mm (p<0.0179). The SFR (annual range) decreased from 90% (86.2%-95.4%) in patients with 1 stone to 84.1% (60%-100%) in those with ≥3 stones. Perioperative complications (annual range) occurred in 9.7% (6%-13.6%) of the patients (Clavien I 5.1% [1.2%-8.6%], Clavien II 2% [0%-4.9%], Clavien IIIa 0.9% [0%-3.4%], Clavien IIIb 1.7% [1.2%-4.8%]) without differences in the annual CR.
  
  
  CONCLUSIONS
  fURS is a safe and efficacious procedure for the treatment of LPS with high primary SFR and low CR. fURS in larger LPS (≥10 mm) is associated with the risk for staged procedures.
authors.affiliation: Department of Urology, Asklepios Hospital Barmbek , Hamburg, Germany .
authors.forename: Ann Kathrin
authors.initials: AK
authors.lastname: Orywal
authors.affiliation: Department of Urology, Asklepios Hospital Barmbek , Hamburg, Germany .
authors.forename: Ann Sophie
authors.initials: AS
authors.lastname: Knipper
authors.affiliation: Department of Urology, Asklepios Hospital Barmbek , Hamburg, Germany .
authors.forename: Christian
authors.initials: C
authors.lastname: Tiburtius
authors.affiliation: Department of Urology, Asklepios Hospital Barmbek , Hamburg, Germany .
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Gross
authors.affiliation: Department of Urology, Asklepios Hospital Barmbek , Hamburg, Germany .
authors.forename: Christopher
authors.initials: C
authors.lastname: Netsch
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000628:therapy*; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D017602:Lithotripsy, Laser / Q000379:methods / Q000639:trends*; D008297:Male; D008875:Middle Aged; D061646:Operative Time; D012017:Referral and Consultation; D012189:Retrospective Studies; D012449:Safety; D015607:Stents; D062606:Tertiary Care Centers; D016896:Treatment Outcome; D020709:Ureteroscopes; D018666:Ureteroscopy / Q000379:methods / Q000639:trends*; D055815:Young Adult