Introduction. Percutaneous nephrolithotomy (PNL), being a minimally invasive procedure, is accompanied by damage to blood vessels and renal parenchyma and, as a consequence, impaired renal hemodynamics. In this work we determined the dynamics of the biomarker of acute kidney injury NGAL depending on the deficit of renal function on the ipsilateral side, the type of stone, the number of accesses, the duration of the procedure, and the initial level of NGAL.
Aim. To study the role of NGAL in determining the potential risks of renal parenchyma damage with PNL in adult patients with nephrolithiasis.
Materials and methods. A total of 46 patients in whom the serum concentration of NGAL was determined before and immediately after PNL, as well as 6, 12, 24 and 48 hours later, were included in the study. PNL was performed under endotracheal anesthesia in the prone position using the standard technique with a 24 Fr nephroscope. When creating an additional (more than one) access, a nephroscope with a 16.5 Fr access sheath was used.
Results. Our results showed that the functional state of the renal parenchyma depended to a greater extent on the initial deficit of more than 50% according to nuclear scintigraphy with staghorn stones of 3-4 types, and to a lesser extent on the duration of the procedures, the number of accesses and the presence of bacteriuria.
Conclusion. Determination of NGAL concentration can be a convenient test for assessing the impairment and restoration of the functional state of the renal parenchyma in the early stages after PNL.

Keywords: markers of kidney injury, NGAL, neutrophil gelatinase-associated lipocalin, percutaneous nephrolithotomy, kidney stones, urolithiasis