- Design
- Two-centre randomised controlled trial
- Population
- 95 patients with ureteric stents for urolithiasis, Germany
- Primary outcome
- Stent encrustation weight at 30 days
- Effect
- About 50% less encrustation; mean difference 22.8 mg (95% CI 2.4 to 43.2)
This randomised trial at two German centres allocated 100 patients needing a ureteric stent for stone disease to a standard 6 F stent or an identical stent with a covalent sulfonic acid coating. Stents were removed at 30 days at the time of definitive stone treatment; 95 were analysed.
Encrustation weight was about half with the coated stent (mean difference 22.8 mg, 95% CI 2.4 to 43.2). Stent-related urinary symptoms rose less (by 3.6 vs 7.8 points), light physical activity was better, fatigue was less, and fewer patients needed antibiotics (7.1% vs 31.8%).
This is a small trial of one product over 30 days, and how the coated stent performs over longer dwell times is not known. Cost and availability in India are also unknown. The general lesson stands: stent symptoms and encrustation are common and worth minimising, starting with the shortest dwell time that is safe.
- Keep ureteric stent dwell time as short as clinically possible.
- Ask about stent symptoms at follow-up; they affect daily activity and work.
- Consider coated stents where available, recognising that evidence is from one small trial.
- Keep a stent register so no stent is forgotten.
Why it matters
Stent symptoms are one of the commonest complaints after stone surgery, and encrustation complicates removal.
Don't overread it
One 100-patient trial of one coating over 30 days; the antibiotic finding rests on small numbers with a very wide interval.
The statistics, in plain English
The encrustation difference interval (2.4 to 43.2 mg) excludes no effect but is wide. The odds ratio for antibiotic need (6.1, CI 1.1 to 33) is very imprecise.
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