The size of the calculi, their location, and complicating factors such as infection should all be considered. Most ureteral calculi smaller than 5 mm pass spontaneously, as do approximately half of calculi between 5 and 10 mm. Calculi larger than 10 mm are unlikely to pass without intervention. Distal calculi are more likely to pass spontaneously than calculi in mid- or proximal ureteral locations; most spontaneous passage occurs within 4 to 6 weeks (strength of recommendation [SOR]: A, prospective cohort studies). All patients with calculi complicated by such factors as obstruction, infection, renal injury, or a single kidney require surgical consultation (SOR: C, expert opinion). Medical expulsion therapy with alpha-blockers (usually tamsulosin) and nifedipine improves passage rates, including for some calculi larger than 10 mm (SOR: A, metaanalysis of prospective cohort studies)
