title: External validation of Resorlu-Unsal stone score as predictor of outcomes after retrograde intrarenal surgery.
abstract: OBJECTIVE
  To externally validate Resorlu-Unsal stone score (RUSS) and to evaluate its predictive accuracy.
  
  
  METHODS
  Data of patients who underwent retrograde intrarenal surgery (RIRS) between October 2013 and June 2015 were collected. RUSS was applied to all patients, and the nomogram was externally validated. Area under the curve (AUC) was used for clinical validity assessment.
  
  
  RESULTS
  A total of 85 patients were included in the study. Mean patient age was 54.3 ± 16.5, and mean stone size was 12.0 ± 6.21 mm. After applying RUSS, 56.5, 28.2, 9.41, and 5.88 % had score 0, 1, 2, and 3, respectively. RUSS was significantly associated with stone location and size. Postoperative stone-free rate was 74.1 %. Postoperative outcomes were significantly associated with RUSS and stone size. RUSS was found to be the only significant independent predictor in multivariate analysis, while it provided high predictive accuracy with an estimated AUC of 0.707.
  
  
  CONCLUSIONS
  RUSS is a simple scoring system that may predict postoperative stone-free rate after RIRS with great efficacy and accuracy.
authors.affiliation: Department of Urology, Hadassah Hebrew University Medical Center, Ein-Kerem, 91120, Jerusalem, Israel. sfoungaristosst@gmail.com.
authors.forename: Stavros
authors.initials: S
authors.lastname: Sfoungaristos
authors.affiliation: Department of Urology, Hadassah Hebrew University Medical Center, Ein-Kerem, 91120, Jerusalem, Israel.
authors.forename: Ofer N
authors.initials: ON
authors.lastname: Gofrit
authors.affiliation: 1st Urology Department, G. Gennimatas Hospital, Aristotle University, Thessaloniki, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Mykoniatis
authors.affiliation: Department of Urology, Hadassah Hebrew University Medical Center, Ein-Kerem, 91120, Jerusalem, Israel.
authors.forename: Ezekiel H
authors.initials: EH
authors.lastname: Landau
authors.affiliation: 1st Urology Department, Laiko Hospital, University of Athens, Athens, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Katafigiotis
authors.affiliation: Department of Urology, Hadassah Hebrew University Medical Center, Ein-Kerem, 91120, Jerusalem, Israel.
authors.forename: Dov
authors.initials: D
authors.lastname: Pode
authors.affiliation: 1st Urology Department, Laiko Hospital, University of Athens, Athens, Greece.
authors.forename: Constantinos A
authors.initials: CA
authors.lastname: Constantinides
authors.affiliation: Department of Urology, Hadassah Hebrew University Medical Center, Ein-Kerem, 91120, Jerusalem, Israel.
authors.forename: Mordechai
authors.initials: M
authors.lastname: Duvdevani
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007669:Kidney Calculi / Q000175:diagnosis* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D009403:Nephrostomy, Percutaneous / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
keywords: Renal stone; Ureteral stones; Ureteroscopy; Urolithiasis