Effect of the location and severity of partial ureteral obstruction on urinary system stone disease formation

This study aimed to observe the effect of the location and severity of partial ureteral obstruction, based on ureteropelvic and ureterovesical junction strictures, on stone formation. Forty 8-week-old male rats were divided into five groups: control and mild/severe proximal or distal ureteral obstruction groups. A partial ureteral obstruction was created according to the type of obstruction by a surgical procedure. After 5 days of intraperitoneal glyoxylate injection, the urine, blood samples, and kidney tissues of the rats were examined. There were significant differences in urine citrate concentrations, pH values, and oxalate/creatinine, citrate/creatinine, and calcium/creatinine ratios between the groups (all p < 0.05). The mean citrate/creatinine ratio was 21.13 ± 0.44 in the control group, 17.31 ± 3.82 in the distal obstruction group, and 15.48 ± 1.87 in the proximal obstruction group. Regarding the degree of obstruction, urine citrate concentrations, pH values, and citrate/creatinine were lower, and the oxalate/creatinine ratio was higher in severe obstruction than in mild obstruction (p < 0.05). This study represents an initial attempt to evaluate a model of partial ureteral obstruction and urolithiasis. The findings indicate that obstruction alters urinary parameters, such as citrate and pH, indirectly increasing the risk of stone formation. Furthermore, stone formation in an obstructed urinary system appears to be a complex process. However, metabolic evaluation and treatment may help prevent stone formation in patients with ureteral obstruction.