Which renal access technique for PCNL is more difficult to teach using simulation?

Abstract

Introduction: Percutaneous nephrolithotomy (PCNL) is a challenging procedure that urology trainees should be familiar with during residency. Simulators, such as the PERC Mentor, allow the development of this competency in a safer, stress-free environment. There are two primary fluoroscopic methods of gaining percutaneous renal access: the triangulation method and the bull's eye method. Our goal was to assess which method is easier to teach novices by using the PERC Mentor simulator. A secondary goal was to assess differences in subjective and objective outcomes.

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, in-person demonstrations and hands-on practice for each technique. They then performed each method and were assessed objectively using the PERC Mentor performance data report and subjectively using the PCNL global rating scale (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. The bull's eye method of obtaining percutaneous access was associated with a significant decrease in operative time (91 seconds vs. 128 seconds, p=0.03) and fluoroscopy time (87 seconds vs. 123 seconds, p=0.03) compared to the triangulation method.

Conclusions: Teaching of both techniques was equally well acquired by students. Both techniques had similar outcomes; however, the bull's eye method was associated with less operative and fluoroscopy time when compared to the triangulation method among novices.

Figure 1

Participant allocation methods.

Figure 2

Effect of percutaneous access (PCA) attempts on objective and subjective performance. PCNL: percutaneous nephrolithotomy