Investigation of factors affecting spontaneous ureteral stone excretion

Abstract

Introduction: Various factors such as structure of stone, size, location of stone and metabolic diseases affect stone excretion. Objectives: The aim of this study was to investigate factors related to spontaneous ureteral stone excretion. Patients and Methods: This descriptive-analytical observational study was conducted in the university urology centers of Yazd, Iran, during a 16-month period. All patients presenting with unilateral ureteral stone whose ureteral stone was confirmed by CT scan or ultrasound were included in the study. Pregnant patients, patients with uncontrolled hypertension, patients with multiple urinary stones, patients with more than four weeks of history of urinary stones, patients with severe hydronephrosis, and patients with malformations of ureter and kidney were excluded from the study. Computed tomography and ultrasound of the patients evaluated the size of the stone, the location of the stone and the degree of hydronephrosis and also perinephric stranding. Results: In this study, 146 patients with mean age of 45.3±15.1 years (ranging from 11 to 84 years) were enrolled. CT scan and ultrasound were diagnostic in 121 (82.9%) and 25 patients (17.1%) respectively. In logistic regression model analysis, size less than 5mm, stone location and male gender and diabetes were significant predictors of spontaneous stone excretion, while size less than 5 mm was the strongest predictor. Conclusion: The strongest predictor of spontaneous excretion is the size of the stone and the next step is the location of the stone. Male gender and diabetes are also contributing factors to the spontaneous excretion of ureteral stones.