Percutaneous renal access: the learning curve of a simplified approach.

Background And Purpose: Fluoroscopically guided techniques to access the kidney percutaneously with low exposure to radiation have been used successfully for many years in our training center. The purpose of this study was to analyze the learning process and to establish the number of procedures necessary for a nonexperienced urologist to achieve competence at performing percutaneous renal access.

Materials And Methods: Eighty-two percutaneous renal accesses in patients with renal stones or ureteropelvic junction obstruction were evaluated. The time needed to perform a correct puncture and the fluoroscopic screening time were recorded for each renal access. Descriptive analysis, analysis of variance, and a Markov chain were used to analyze the results.

Results: The rate of success increased from 82.5% to 97.6% after the first 40 punctures. Puncture time and fluoroscopy time decreased as the number of procedures increased. Incidence of complications was 30% for the first 20 cases, decreasing to 10% in the next 20 cases and 3.7% in the last 33 cases.

Conclusions: The fluoroscopy-guided approach used in this study is an effective and reproducible technique. Our analysis revealed that at least 50 procedures are needed to acquire reliable competence in obtaining access to the kidney.