title: Incidence and Predictors for Ipsilateral Hydronephrosis Following Ureteroscopic Lithotripsy.
abstract: OBJECTIVE
  To review our experience in using ureteroscopy (URS) with lithotripsy for renal or ureteral calculi to determine the incidence and predictors of postprocedural ipsilateral hydronephrosis.
  
  
  METHODS
  Records of 324 URS cases for renal or ureteral calculi with imaging performed 4-12 weeks postprocedure were reviewed. Ipsilateral hydronephrosis was determined by computed tomography scan or renal ultrasound. Univariate and multivariate analyses determined the factors associated with hydronephrosis.
  
  
  RESULTS
  176 men and 148 women with a median age of 50 years were included. Median stone size was 6 mm and operative duration was 60 minutes; 30% of patients had multiple calculi; and 35% had undergone a prior ipsilateral URS. Overall, 49 of 324 patients (15%) had evidence of hydronephrosis, with 65% of these patients having symptoms and 40% requiring ancillary procedures. On multivariate analysis, increasing stone diameter (odds ratio [OR] 8.9, 95% confidence interval [CI] 1.9-23.8, P = .03), prior ipsilateral URS (OR 7.7, 95% CI 1.8-28.2, P = .006), longer operative duration (OR 6.5, 95% CI 1.8-16.3, P = .02), and renal colic symptoms (OR 48.3, 95% CI 14.7-71.4, P <.001) independently predicted hydronephrosis. Conversely, other factors including stone impaction at procedure, ureteral dilation, use of an access sheath, intraoperative perforation, or use of a stent did not associate with ipsilateral hydronephrosis.
  
  
  CONCLUSIONS
  In this contemporary cohort study, 15% of patients undergoing URS had evidence of ipsilateral hydronephrosis. Larger stone size, longer OR duration, prior ipsilateral URS, and recurrent colic were associated with an increased likelihood for this observation. Patients and stone cases with such characteristics likely warrant imaging modalities beyond plain radiography.
authors.affiliation: Division of Urology, Penn State Milton S. Hershey Medical Center, Hershey, PA.
authors.forename: Meredith L
authors.initials: ML
authors.lastname: Barbour
authors.affiliation: Division of Urology, Penn State Milton S. Hershey Medical Center, Hershey, PA. Electronic address: jraman@hmc.psu.edu.
authors.forename: Jay D
authors.initials: JD
authors.lastname: Raman
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000453:epidemiology*; D015994:Incidence; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D061646:Operative Time; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome; D014514:Ureteral Calculi / Q000628:therapy*; D018666:Ureteroscopy / Q000009:adverse effects*