Introduction: Percutaneous nephrolithotomy is a challenging procedure that urology trainees should be familiar with during residency. The advent of simulators, such as the PERC Mentor, allows the development of this competency in a safer and stress-free environment. There are two primary methods of gaining percutaneous renal access: the triangulation method and the bull’s eye method. It is generally believed that it is more difficult to teach triangulation access; however, to our knowledge, there is no study comparing the skill acquisition of both techniques. Our goal was to assess which method is associated with easier attainment in aptitude by using the PERC Mentor simulator. A secondary goal was to assess differences in subjective and objective outcomes between the two methods.

Methods: Fifteen simulator- and procedure-naive medical trainees were randomized into two groups using a crossover randomized study design. Participants were provided with written, video, and live in-person instructions on how to perform each technique. They all performed both methods on the PERC Mentor simulator and were assessed objectively using the PERC Mentor performance data report and subjectively using the Percutaneous Nephrolithotomy-Global Rating Scale (PCNL-GRS) scoring system. Statistical analysis was performed using Student’s t-test and non-parametric Wilcoxon signed-rank test.

Results: There was no statistical difference in the outcomes and complication rates between the two methods. However, the bull’s eye method of obtaining percutaneous renal access was associated with significantly decreased operative time, as well as fluoroscopy time compared to the triangulation method.

Conclusions: Teaching of both techniques was equally well-received by students. Percutaneous renal access could be obtained using either technique successfully. The bull’s eye method, however, was associated with less operative and fluoroscopy time when compared to the triangulation method.