Systematic Review on the Learning Curve of Percutaneous Nephrolithotomy: Operative Time, Fluoroscopy Time, Stone-free...

To systematically review the learning curve of percutaneous nephrolithotomy (PCNL) among urology trainees, focusing on the number of procedures required to achieve proficiency and key performance metrics.

A systematic review was conducted in accordance with the PRISMA and the EAU guidelines. PubMed/Medline, Scopus, and Embase were searched up to December 9, 2024, for studies on learning curves in urology trainees performing PCNL on adult humans. Outcomes included operative time, fluoroscopy time, stone-free rate, puncture time and success, complications, and safety indicators. The protocol was registered in PROSPERO (CRD42025633899).

Seventeen studies (2230 patients) were included from 807 records. Operative time plateaued after 40-50 cases. Fluoroscopy time improved with experience and plateaued after 30-115 cases, with faster learning in supine positioning. Puncture success neared 100% after 25-50 cases, and puncture time improved after 36 cases. Complication and retreatment rates declined over time, although plateau phases were rarely reported. Stone-free rates and patient safety indicators improvement inconsistently across studies. Considerable heterogeneity in outcome definitions and reporting methods precluded pooled analysis.

Performance plateaus in PCNL are generally observed after 30-60 procedures, depending on surgical approach and stone complexity. Operative and fluoroscopy times, puncture success, and complication rates improved with experience. Stone-free and retreatment rates showed greater variability, with no clear patterns or plateaus. However, heterogeneity in reporting and outcome definitions currently limits inter-study comparisons and precludes meta-analysis. Standardized training and uniform evaluation methods are needed to better define surgical proficiency.