The effect of standard percutaneous nephrolithotomy, miniaturized percutaneous nephrolithotomy and retrograde intrarenal surgery on biomarkers of renal injury: a randomized clinical trial.

Background: Observational studies on the association of endourological procedures with renal parenchymal damage are lacking. This randomized trial examined the effect of standard percutaneous nephrolithotomy (sPCNL) in comparison with miniaturized-PCNL (mini-PCNL) and retrograde intrarenal surgery (RIRS) for nephrolithiasis treatment on novel biomarkers of renal injury.

Methods: Seventy-five patients were randomized in a 1:1:1 ratio to receive sPCNL, mini-PCNL and RIRS for nephrolithiasis. The ratios of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1) and interleukin-18 (IL-18) normalized for urinary creatinine (Cr) were calculated from urine samples collected at baseline (2-h preoperatively) and at 2-, 6-, 24- and 48-h postoperatively. Two-way mixed analysis of variance (ANOVA) for repeated measurements was used to evaluate the effects of type of procedure and time on studied biomarkers.

Results: Between baseline and 2-h postoperatively, no significant differences were observed in NGAL/Cr changes between sPCNL [median (interquartile range) 9.46 (4.82-14.9)], mini-PCNL [12.78 (1.69-25.24)] and RIRS [6.42 (2.61-23.90)] ( = .902). Similarly, no between-group differences were observed for KIM-1/Cr ( = .853) and IL-18 ( = .980) at 2 h, and all biomarkers at any time-point postoperatively. Within-groups, significant increases from baseline were noted for NGAL/Cr (sPCNL,  < .001; mini-PCNL,  < .001; RIRS,  = .001), KIM-1/Cr and IL-18/Cr at 2 h; progressively lower increases from baseline were noted in all groups for KIM-1/Cr and IL-18/Cr at 6-, 24- and 48-h postoperatively. As such, a significant effect of time but not of type of procedure was evidenced with two-way mixed ANOVA. No significant between-group differences were observed in acute kidney injury incidence and complications.

Conclusions: The endourological procedures under study are associated with similar patterns of early tubular injury, detected by novel biomarkers, which is largely reduced within 48 h and no changes in glomerular function.