title: Value of preoperative stone scoring systems in predicting the results of percutaneous nephrolithotomy.
abstract: BACKGROUND
  Guy's Stone Score and S.T.O.N.E. Nephrolithometry nomograms have been introduced for systematic and quantitative assessment of kidney stones. The aim of this study was to reveal the value of two scorings systems, Guy and S.T.O.N.E, most frequently used for predicting postoperative stone-free status prior to Percutaneous Nephrolithotomy (PCNL), in the prediction of postoperative results of PCNL.
  
  
  METHODS
  We retrospectively examined patients who underwent PCNL. Preoperative abdominopelvic computerized tomography images of these patients were reviewed and scored according to the Guy and S.T.O.N.E. systems. The relationship between the Guy and S.T.O.N.E. scores, and their postoperative stone-free status, complications based on Clavien system, operation time, fluoroscopy time and period of hospitalization was compared.
  
  
  RESULTS
  We identified a total of 102 patients who underwent PCNL between 2010 and 2014, having met the inclusion criteria. The relationships between the total S.T.O.N.E score and Clavien score (p <0.001); time of operation (p = 0.012) and stone-free status (p <0.001); Guy stone score and Clavien score (p <0.001); and period of hospitalization (p <0.001) and time of operation (p <0.001) were found to be statistically significant. There was no statistically significant relationship between Guy score and stone-free status and no statistically significant relationship was found between fluoroscopy time and both stone scoring systems.
  
  
  CONCLUSIONS
  Guy and S.T.O.N.E. scoring systems may be used as effective instruments particularly for predicting postoperative complications.
authors.affiliation: Sakarya University Training and Research Hospital, Sakarya, Turkey.
authors.forename: Şükrü
authors.initials: Ş
authors.lastname: Kumsar
authors.affiliation: Sakarya University Training and Research Hospital, Sakarya, Turkey.
authors.forename: Hüseyin
authors.initials: H
authors.lastname: Aydemir
authors.affiliation: Sakarya University Training and Research Hospital, Sakarya, Turkey.
authors.forename: Fikret
authors.initials: F
authors.lastname: Halis
authors.affiliation: Sakarya University Training and Research Hospital, Sakarya, Turkey.
authors.forename: Osman
authors.initials: O
authors.lastname: Köse
authors.affiliation: Sakarya University Training and Research Hospital, Sakarya, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Gökçe
authors.affiliation: Sakarya University Training and Research Hospital, Sakarya, Turkey.
authors.forename: Oztug
authors.initials: O
authors.lastname: Adsan
keywords: complication; computerized tomography; percutaneous nephrolithotomy; renal stone