Role of ureteral wall thickness and computed tomography imaging in predicting spontaneous passage of ureteral stones

Urolithiasis is a common health problem with a high recurrence rate, and effectively balancing follow-up with intervention is important for patient safety. In this context, our study aims to identify criteria that can predict the likelihood of spontaneous passage (SP) of ureteral stones.

A retrospective analysis was performed on 2,773 patients who presented to our hospital with renal colic over a 4-year period. The study included 897 patients with unilateral ureteral stones measuring ≤10 mm, identified using non-contrast computed tomography, and inflammatory serum markers assessed through biochemical testing. Variables analyzed to predict the likelihood of SP included stone size, lateralization and location, ureteral wall thickness (UWT) at the stone site, stone density, degree of hydronephrosis (HN), ureteral length, parenchymal thickness and density, and various biochemical parameters.

It was determined that the SP of ureteral stones was considerably affected by larger stone size (right >6.5 mm, left >6 mm), higher stone density (>957 Hounsfield units), increased UWT (>1.7 mm), presence of high-grade HN (grade ≥2), and elevated neutrophil-lymphocyte ratio (NLR) (>2.15) and platelet-lymphocyte ratio (PLR) (>10.28) values in blood. No statistically significant relationship was observed between SP and ureteral length, renal parenchymal thickness, or renal parenchymal density. It was found that when the UWT at the level of the ureteral stone exceeded 1.7 mm, the risk of the stone not passing spontaneously increased by 706.5 times in univariate logistic regression (LR) analysis and by 337.9 times in multivariate LR analysis compared with individuals with a wall thickness below this threshold.

Our study demonstrated that, in addition to stone size and location, increased UWT at the stone level, higher stone density, the presence of concomitant high-grade HN, and elevated NLR and PLR values in the blood could be used as criteria to determine the likelihood of SP of ureteral stones. According to our results, UWT was shown to be a stronger risk factor for failure of SP than stone size.

The findings indicate that wall thickness around ureteral stones is a risk factor with a higher negative predictive value for SP than the stone size and location.