Factors predicting the spontaneous passage of a ureteric calculus of ≤ 10 mm

Objective: To evaluate the outcome of the expectant management of ureteric stones and to determine the factors predictive of the spontaneous passage of stones. Patients and methods: We retrospectively reviewed the medical records of patients who had ureteric stones of ≤ 10 mm and who were treated conservatively at our institutions during the period 2008–2013. The stone-passage rate and time, and different clinical, laboratory and radiological variables, were analysed. Results: In all, 163 patients with ureteric stones were enrolled in the study, of whom 127 (77.9%) passed their stones spontaneously, with a mean (SD) passage time of 24.0 (8.09) days. The cumulative stone-passage rate was 1.6%, 15%, 41.7%, 72.4%, 89.8% and 98.4% at 7, 14, 21, 28, 35 and 42 days from the first presentation, respectively. Patients with a high pain-scale score, stones of ≤ 5 mm, a lower ureteric stone, a high white blood cell count and those with absent computed tomography (CT) findings of perinephric fat stranding (PFS) and tissue-rim sign (TRS) had a higher likelihood of spontaneous stone passage. Patients with stones of ≤ 5 mm, stones in the lower ureter and those with no PFS had a shorter spontaneous passage time. In a multivariate analysis the absence of PFS and TRS were the only significant predictors for spontaneous stone passage (P 0.001 and 0.002, respectively). Conclusions: The spontaneous ureteric stone-passage rate and time varies with different factors. The absence of CT findings of PFS andTRSare significant predictors for stone passage, and should be considered when choosing the expectant management.