Strong Correlation but Moderate Agreement: Comparison of Clavien-Dindo and Clavien-Madadi Classification Systems in Pediatric Percutaneous Nephrolithotomy.
BACKGROUND The Clavien-Dindo (CD) classification is widely used for grading surgical complications; however, its applicability in pediatric populations may be limited due to differences in perioperative management, particularly the routine use of general anesthesia. The Clavien-Madadi (CM) classification has been proposed as a pediatric-specific alternative. This study aimed to compare CD and CM classifications in pediatric percutaneous nephrolithotomy (PNL) and evaluate their agreement and clinical relevance. METHODS A total of 270 pediatric PNL procedures were retrospectively analyzed. Complications were graded using both CD and CM systems. Correlation and agreement were assessed using Spearman's coefficient and kappa statistics. Clinical predictors of complications were also evaluated. RESULTS Thirty-five complications (12.9%) were identified. A very strong correlation was observed between CD and CM classifications (ρ = 0.964, p < 0.001), whereas agreement analysis showed only moderate concordance (κ = 0.407). Weighted kappa indicated substantial agreement (κ ≈ 0.82), suggesting discrepancies were mainly between adjacent grades. The CM system demonstrated a consistent tendency to assign lower grades for certain interventional complications. Stone volume (p = 0.017), operation time (p = 0.044), and fluoroscopy time (p = 0.035) were significantly associated with complications. CONCLUSIONS Despite strong correlation, CD and CM classifications are not interchangeable. The CD system may overestimate complication severity in pediatric patients due to its anesthesia-based grading criteria, whereas the CM system appears more aligned with pediatric clinical practice.