title: A standardized scoring system in the prediction of success and complications of percutaneous nephrolithotomy: Guy's stone scoring system.
abstract: OBJECTIVE
  In this study, our aim was to determine the role of Guy's stone scoring system (GSS) in the prediction of percutaneous nephrolithotomy (PNL) success and its ability to foresee potential complications in consideration of Clavien grading system (CGS).
  
  
  METHODS
  The data of 244 patients who underwent PNL between January 2009 and May 2014 were retrospectively examined. Renal stones were evaluated using GSS with the aid of the patients' preoperative radiological evaluations and their postoperative complications were assessed with CGS.
  
  
  RESULTS
  Mean age of the patients (men, n=166; 68% and women, n=78; 32%) was 46.50±13.12 years (range, 16-80 yrs). Clinically significant residual stones were not detected in 195 (79.9%) patients, while they were found in 49 (20.1%) patients. Guy's stone scores of 1, 2, 3 and 4 points were estimated in 21.3, 37.7, 29.9, and 11.1% of the cases, respectively. Based on modified Clavien complication grading system, complications were categorized as Clavien grade 1, 2 and 3 in 81.9, 17.2, and 0.8% of the cases, respectively. Clavien Grade 4 and 5 complications were not encountered. A statistically significant correlation was found between Guy's Stone scores and Clavien grades (p<0.02). A statistically and highly significant difference was detected between Guy's stone scores of the cases with respect to residual stones (p=0.001; p<0.01).
  
  
  CONCLUSIONS
  Our study findings have revealed that GSS is a successful and easily applicable method for the prediction of success and likelihood of complications of PNL.
authors.affiliation: Department of Urology. Fatih Sultan Mehmet Research & Training Hospital. Istanbul. Turkey.
authors.forename: Fatih
authors.initials: F
authors.lastname: Uruc
authors.affiliation: Department of Urology. Fatih Sultan Mehmet Research & Training Hospital. Istanbul. Turkey.
authors.forename: Ozgur Haki
authors.initials: OH
authors.lastname: Yuksel
authors.affiliation: Department of Urology. Fatih Sultan Mehmet Research & Training Hospital. Istanbul. Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Urkmez
authors.affiliation: Department of Urology. Fatih Sultan Mehmet Research & Training Hospital. Istanbul. Turkey.
authors.forename: Aytac
authors.initials: A
authors.lastname: Sahin
authors.affiliation: Department of Urology. Dumlupinar University Faculty of Medicine. Kutahya. Turkey.
authors.forename: Bekir
authors.initials: B
authors.lastname: Aras
authors.affiliation: Department of Urology. Fatih Sultan Mehmet Research & Training Hospital. Istanbul. Turkey.
authors.forename: Ayhan
authors.initials: A
authors.lastname: Verit
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous / Q000009:adverse effects*; D011379:Prognosis; D012074:Remission Induction; D012189:Retrospective Studies; D055815:Young Adult