Introduction. In recent years, there has been a persistent trend towards an increase in the incidence of urolithiasis. The treatment of large and complex kidney stones greatest difficulty is one of the challenges. Such stones, as well as surgical methods of their removal, can have an adverse effect on the functional state of the kidneys, which confers a significant medical, social and economic problem.

The purpose of this study is to identify factors affecting the functional state of the kidneys in the postoperative period when using various video endoscopic methods of surgical treatment of patients with large and complex kidney stones.

Materials and methods. We analyzed the results of treatment of 97 patients with large and complex kidney stones. Depending on the treatment, all these patients were divided into three groups: 1st – 44 (45,36%) patients who underwent percutaneous nephrolithotripsy in prone position, 2nd – 29 (29,9%) patients who underwent percutaneous nephrolithotripsy in the supine position, 3rd – 24 (24,74%) of the patient who underwent pyelolithotomy with laparoscopic and retroperitoneoscopic approaches. Assessment of the area and density of stones was performed by computed tomography. The glomerular filtration rate (GFR) was calculated by CKD-PI formula and dynamic nephroscintigraphy was used to assess of each kidney function.

Results. In the postoperative period, the decrease in GFR was most pronounced in the group of patients after percutaneous nephrolithotripsy in the supine position. Among the most significant factors worsening this indicator were the volume of intraoperative (r=0,410, p<0,001, n=97) and postoperative blood loss (r=0,294, p <0.01, n=97), duration of surgery (r=0,187, p <0,1, n=97), density (r=0,426, p <0,001, n=97) and the area (r=0,554, p <0,001, n=97) of the concretion, as well as the body mass index (r=0,294, p <0,01, n=97).

Conclusions. The most significant factors that have a negative impact on the functional state of the kidneys were the density and area of the stone, the patient's body mass index and the volume of intraoperative blood loss. The least deterioration of kidney function in the postoperative period was observed with endoscopic pyelolithotomy, and the greatest – with percutaneous nephrolithotripsy in the patient's back position.