Systematic Review on the Learning Curve of Percutaneous Nephrolithotomy: Operative Time, Fluoroscopy Time, Stone-free Rate, Puncture Performance, Complications, and Safety Indicators.

Objective: 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.

Methods: 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).

Results: 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.

Conclusion: 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.