EXTRACORPOREAL SHOCKWAVE LITHOTRIPSY OF STONES IN LOWER CALICES OF KIDNEY

The article presents the results of the study aimed to evaluation of possible relationship between anatomical structure of the renal pelvis of the kidney, the size of the stone and the effectiveness of extracorporeal shockwave lithotripsy (ESWL) of stones in lower calices of kidney, defined as "stone-free state". ESWL was performed in 285 patients. Sizes of stones varied from 5 to 25 mm. With interval distribution of stone sizes, the greatest number of cases was detected with size of 5 to 12 mm. The destruction of stone required one ESWL session in 196 cases, and three sessions only in 12 cases. The total number of pulses per one stone did not exceed 9500, and more than 70% of the stones have been effectively destroyed with less than 3000 pulses. The result of treatment was assessed 3-4 months after the last ESWL session on the basis of ultrasound and X-ray examination using nominal (dichotomous) scale. In addition, for verification of significant (expected and unexpected) correlations, exploratory analysis of the correlation matrices of factors possibly affecting the discharge of stone fragments was performed. Positive treatment outcome was recorded in 212 (74,4%) patients. Residual stone fragments (≥ 5 mm) were identified in 73 (25,6%) patients; in 69 patients fragments corresponded to the initial localization and 4 fragments were located in the pelvis and calices of middle and lower segments of the kidney. Statistical processing found no association between the size of the stone and the number of ESWL sessions required for its destruction (P=0,4056). The analysis of relationship between the nature of the complications and size of stone revealed differences, but there were no significant differences in median test (p=0.1067). Based on exploratory analysis and correlations identified, in-depth evaluation was carried out on three factors: the size of the stone, length of lower calices neck, and pyelocaliceal corner. Width of lower calices neck as a statistically nonsignificant criterion was excluded from further analysis. A full-scale statistical analysis resulted in a number of conclusions that reflect the dependence of the efficiency of ESWL of stones in lower calices of kidney on size of the stone and a number of anatomical features of the renal pelvis system

kidney stones, stones in lower calices, extracorporeal shockwave lithotripsy, length of lower calices neck, pyelocaliceal corner