Suction ureteroscopy: higher stone-free rates, less sepsis, and device matters

Design

Systematic review with Bayesian random-effects network meta-analysis and meta-regression

Population

17 studies, 3657 patients with renal stones 2 cm or less (1677 aspiration sheath, 56 in-scope suction, 1924 control)

Primary outcome

30-day stone-free rate

Effect

Aspiration sheath OR 2.5 (95% CrI 2.0 to 3.1); postoperative sepsis OR 0.40 (0.12 to 0.97); device-level estimates ranged from OR 1.6 to 5.4

Seventeen comparative studies and 3657 patients were combined in a Bayesian network meta-analysis of suction-assisted flexible ureteroscopy for renal stones of 2 cm or less — flexible aspiration navigable sheaths, direct in-scope suction, and conventional access sheaths.

Aspiration sheaths gave a higher 30-day stone-free rate, odds ratio 2.5, and lower odds of postoperative sepsis at 0.40. Fever, complications and operative time also favoured them. Direct in-scope suction pointed the same way with far less precision, on only 56 patients.

The finding that stops this being a simple recommendation is the spread between devices. One sheath returned an odds ratio of 5.4 for stone clearance with a credible interval reaching 29; another showed no significant difference at all. So 'suction' is not one intervention, and a unit adopting it is choosing a specific device on evidence that varies from strong to absent depending on which one.

• Where an aspiration sheath is available, use it for renal stones of 2 cm or less.
• Check the evidence for the specific device you are buying, not for suction as a category.
• The sepsis signal is the reason to prioritise this in infected or high-risk stone patients.
• Intrarenal pressure control is the presumed mechanism; technique still governs it.
• Direct in-scope suction rests on 56 patients here — promising, not established.

Why it matters

It moves suction from a preference to a default for small renal stones, while showing the choice of device is not interchangeable.

Don't overread it

Mostly non-randomised comparative studies; the authors call for larger prospective trials.

The statistics, in plain English

Credible intervals from a Bayesian analysis are read like confidence intervals, and their width is the story here: 2.0 to 3.1 for aspiration sheaths overall is a firm result, while 1.0 to 29.0 for one device means almost nothing is pinned down. The sepsis estimate (0.40, 0.12 to 0.97) just excludes 1.0, so it is the weakest of the strong claims. Network meta-analysis of largely non-randomised comparative studies inherits their selection bias — surgeons choose suction for the cases they expect to go well.

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