Longer remaining membranous urethra was linked to faster continence after robotic prostatectomy

Design

Bayesian longitudinal meta-analysis of cohort studies

Population

938 men after robot-assisted radical prostatectomy across 8 cohorts

Primary outcome

Urinary continence over 12 months by postoperative MRI urethral length

Effect

OR 1.31 (1.04–1.67) per mm at 1 month; 1.55 (1.21–2.03) at 12 months

A Bayesian longitudinal meta-analysis combined eight cohorts (938 men) that measured membranous urethral length on MRI after robot-assisted radical prostatectomy and followed urinary continence.

At a reference length of about 13.5 mm, modelled continence was 26% at 1 month, 58% at 3 months, 76% at 6 months and 88% at 12 months. Each extra millimetre was associated with higher odds of continence: OR 1.31 at 1 month and 1.55 at 12 months, and a 22% shorter time to reaching 50% continence.

Removing one influential study weakened the association to the point of uncertainty, and the authors rate certainty as low. Preoperative urethral length is already used in counselling; this extends the idea to what is preserved after surgery. Whether a postoperative MRI adds anything to established predictors has not been shown, so it is not a reason to order one routinely.

• Consider membranous urethral length when counselling men about continence recovery after prostatectomy.
• Preserve as much membranous urethra as oncologically safe during apical dissection.
• Do not order routine postoperative MRI to predict continence; its added value is unproven.
• Tell men that most regain continence by 12 months, with recovery slower in the first 3 months.

Why it matters

It puts numbers on how much the preserved urethra may matter for the recovery men care most about.

Don't overread it

Low certainty, sensitive to one study, and not shown to add to existing predictors.

The statistics, in plain English

An odds ratio of 1.55 per millimetre at 12 months is a sizeable effect, but the credible interval became compatible with no effect when one study was removed, which is why certainty is rated low.

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