Ureteral Stones and Their Impact on Changes in Renal Function. Peculiarities of Predicting the Recovery of Renal Function After Removal of Unilateral Ureteral Obstruction (Literature review)

Urolithiasis is a common chronic disease of the urinary system, manifested by the formation of stones in the kidneys and urinary tract organs. Urolithiasis ranks second in the incidence of kidney and urinary tract diseases and fourth among the causes of disability due to urological pathology. The medical and social significance of urolithiasis is due to the fact that in the vast majority of patients it develops in an active working age and leads to disability. The prevalence of urolithiasis is directly related to living conditions (nutrition, environmental situation, climatic conditions, quantity and quality of fluid consumed). Ureteral calculi are a pathological condition in which stones formed in the kidneys migrate to the bladder, causing ureteral obstruction and acute renal colic. Urethra stones can cause serious complications. The consequences of this are more severe than when the stones are otherwise localized. Calculi disrupt urine flow, causing pathological changes in the kidneys and the ureter itself. Ureteral obstruction can lead to inflammation of the renal tissue, the onset and progression of hydronephrotic transformation of the kidney and, as a result, nephron death, loss of kidney function, and renal failure. Due to the large number of cases of patient referrals regarding obstruction by ureteral calculi, the relevance of the search and development of modern minimally traumatic treatment methods is emphasized. To date, many methods of diagnosis and minimally invasive surgical interventions for ureteral stones of any localization have been developed. However, insufficient attention is paid to studying the issue of changes in the functional state of a blocked kidney, the likely early and long-term consequences of ureteral obstruction, taking into account the localization of stones and the duration of obstruction, and the possibilities of restoring lost kidney function after a complex of therapeutic measures. An accurate prediction of the recovery of renal function after the removal of a long-term ureteral block is of great clinical importance for urologists and nephrologists. The analysis of literature sources shows that today there are a number of issues that arise when trying to predict the degree of loss of renal function. Most previous methods and studies have used univariate analysis, which considers a single factor independently of other variables However, in the real world, several parameters must be taken into account that can significantly affect the prognosis (duration of obstruction, size and location of the stone, age and gender of the patient). Some of these factors can only be studied under experimental conditions. In particular, these include the function of the contralateral kidney, pyelolymphatic reflux, the presence of an opportunistic urinary tract infection, and the simultaneous use of nephrotoxic agents and medications that can have a harmful effect on renal function. This situation requires the creation of such a universal method that would assess the residual functional capacity of the kidney after the removal of calculous obstruction. Along with this, the methodology should be as accurate as possible, accessible, and take into account several important parameters at the same time.