title: [The use of S.T.O.N.E. scale in patients undergoing percutaneous nephrolithotomy].
abstract: OBJECTIVE
  The aim of this study was to apply the S.T.O.N.E. scale on our patients undergoing PCNL to predict stone free rate and complications using the modified Clavien scale.
  
  
  METHODS
  A historical cohort of patients undergoing PCNL was analyzed. All patients with computed tomography to assess stone-free rate with the S.T.O.N.E. scale and complications were evaluated by the modified Clavien scale.
  
  
  RESULTS
  In 102 patients 104 procedures were performed; the mean age was 48.4 years and 71% were women. The distribution of cases were classified as mild: 6.7%, moderate: 63.5% and severe: 29.8%. The stone free rate after the first procedure globally reached 58% and by grade was: mild 85.7%, moderate 71.2% and severe 25%. The RR for residual stones after the first procedure was 2.4 for moderate grade (CI 0.3 to 15, p=0.03) and 4.9 for severe grade (CI 0.7 - 30.9, p=0.08). The overall complication rate was 33%, separately Clavien 1: 14.4%, 2: 9.6%, 3a: 2.9%, 3b: 2.9% 4:1.9%, 5:1%.
  
  
  CONCLUSIONS
  The S.T.O.N.E. scale applied in our population can predict accurately and easily stone free rate in patients undergoing PCNL. We found no predictive association for this scale on complications.
authors.affiliation: Service of Urology. Hospital de Especialidades. Centro Médico Nacional Siglo XXI. Instituto Mexicano del Seguro Social. Distrito Federal. México.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: González-Rodríguez
authors.affiliation: Service of Urology. Hospital de Especialidades. Centro Médico Nacional Siglo XXI. Instituto Mexicano del Seguro Social. Distrito Federal. México.
authors.forename: Efrain
authors.initials: E
authors.lastname: Maldonado-Alcaraz
authors.affiliation: Service of Urology. Hospital de Especialidades. Centro Médico Nacional Siglo XXI. Instituto Mexicano del Seguro Social. Distrito Federal. México.
authors.forename: Eduardo Alonso
authors.initials: EA
authors.lastname: Serrano-Brambila
authors.affiliation: Service of Urology. Hospital de Especialidades. Centro Médico Nacional Siglo XXI. Instituto Mexicano del Seguro Social. Distrito Federal. México.
authors.forename: Virgilio Augusto
authors.initials: VA
authors.lastname: López-Sámano
authors.affiliation: Service of Urology. Hospital de Especialidades. Centro Médico Nacional Siglo XXI. Instituto Mexicano del Seguro Social. Distrito Federal. México.
authors.forename: Jorge
authors.initials: J
authors.lastname: Moreno-Palacios
mesh_terms: D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous; D011183:Postoperative Complications / Q000453:epidemiology; D011379:Prognosis