Two most important predictors of stone passage are stone size and location.
Contemporary data from MIMIC study:
How long to manage conservatively?
AUA guidelines suggest intervening after 4 – 6 weeks.
- Experimental data on unilateral complete obstruction suggest irreversible renal damage can occur after six weeks (noting most stones don’t cause complete obstruction)
- Most studies suggests if stones pass, most will have done so by around 30 – 40 days
- EAU – “estimated 95 % of stones up to 3 mm pass within 40 days”
Repeat hospital visits, uncontrolled pain, worsening renal function and any signs of infection also should prompt management.
Do you give tamsulosin?
Contradictory evidence with some studies showing benefit and some trials showing no benefit.
Meta-analysis finds greatest benefit in distal stones > 5 mm.
EAU – “MET seems to be efficacious for treating patients with ureteric stones amenable to conservative management – greatest benefit might be among those with > 5mm distal ureteric stones”
“Consider a-blockers for MET as one of the treatment options for distal stones > 5 mm”
AUA – “Uncomplicated ureteric stones < 10 mm should be offered observation, and those with distal stones < 10 mm should be offered MET”
- Nifedipine (calcium channel blocker) has insufficient data (one positive and one negative trial) and cannot be recommended
- AUA recognises trials showed no benefit for distal stones smaller than 5 mm (and these have high rates of passage anyway)
- Not many trials include proximal or mid ureteric stones and no benefit has been demonstrated for these stones (AUA panel suggests a trial can be considered anyway)
Use of alpha blockers for MET is off-label.
UK SUSPEND 2015 trial (Pickard)
- Tamsulosin vs nifedipine vs placebo, 1100 patients
- Single ureteric stone up to 10 mm, 65 % distal stones
- 80 % free from intervention at 4 weeks – same in all three groups
- Additional 7-8 % required intervention up to 12 weeks – no difference in groups
- No benefit to either medication demonstrated
- No benefit in subgroup analysis for size and location (though not specifically powered)
- Not included in AUA analysis due to different outcome (need for intervention) rather than radiological evidence of stone passage
- Trial notes that lack of routine imaging to confirm stone passage was offset by follow up to 12 weeks at which time symptoms should declare
Australian trial (Furyk 2016)
- Distal stones only
- CT at 28 days
- 87 % passage in tamsulosin, 81 % placebo – no difference statistically
- 83 % vs 61 % for pre-specified subgroup > 5 mm – significant – NNT 4.5
Chinese trial (Ye 2018)
- 3000 patients
- Distal stones, CT at 28 days
- 86 vs 79 % passage favouring tamsulosin, significant, more so in > 5 mm stones
- Less pain relief and time to stone passage with tamsulosin
Anything else to try improving stone passage?
- Meta-analysis of 3 trials concludes sexual intercourse benefit in facilitating stone passage in men with ureteric stones