title: Evaluation of the learning curve for percutaneous nephrolithotomy.
abstract: OBJECTIVE
  To determine the number of percutaneous nephrolithotomy (PCNL) operations which are required to achieve competence or excellence.
  
  
  METHODS
  One hundred and five consecutive PCNL operations performed by a fellow in endourology, with no previous experience in performing solo PCNL, were studied. Operation duration, stone extraction percent, stone-free rate, number of access, tubeless cases, and complications were studied in sequential groups of 15 patients as the surgeon gained experience.
  
  
  RESULTS
  Operation duration decreased from the mean of 95.4 minutes in the first to 15th patients to 78.3 minutes in the 31st to 45th patients, and then remained unchanged. Minor complications were only observed in the first to 45th patients. Stone extraction percent increased from the mean of 88.3% in the first to 15th patients to 99.3% in 91st to 105th patients. Percentage of patients with no residual fragments decreased from 53% in the first to 15th patients to 6.7% in the 91st to 105th patients. No statistically significant differences were observed in estimated blood loss or transfusion rate between sequential groups of subjects.
  
  
  CONCLUSIONS
  An improvement in operation duration was observed, and absence of complications was achieved after 45 cases. The improvement in stone clearance was observed up to the last subjects. Competence and excellence were achieved after 45 and 105 operations, respectively.
authors.affiliation: Urology and Nephrology Research Center, Tehran, Iran.
authors.forename: Seyed Amir Mohsen
authors.initials: SA
authors.lastname: Ziaee
authors.forename: Mehrdad Mohammadi
authors.initials: MM
authors.lastname: Sichani
authors.forename: Amir Hossein
authors.initials: AH
authors.lastname: Kashi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Samzadeh
mesh_terms: D000328:Adult; D016063:Blood Loss, Surgical / Q000706:statistics & numerical data; D001803:Blood Transfusion / Q000706:statistics & numerical data; D002983:Clinical Competence / Q000706:statistics & numerical data*; D004503:Education, Medical, Graduate / Q000706:statistics & numerical data*; D006801:Humans; D007431:Intraoperative Complications; D059032:Learning Curve; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous / Q000706:statistics & numerical data*; D013663:Teaching / Q000379:methods; D013996:Time and Motion Studies