Evaluation of the learning curve for percutaneous nephrolithotomy

Abstract

Purpose: To determine the number of percutaneous nephrolithotomy (PCNL) operations which are required to achieve competence or excellence.

Materials and 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.

Conclusion: 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.