Omitting renorrhaphy in off-clamp partial nephrectomy is non-inferior, not better

Design

systematic review and random-effects meta-analysis (PRISMA 2020) of four comparative studies: one randomised trial and three propensity-score-matched studies

Population

787 patients undergoing purely off-clamp robot-assisted partial nephrectomy, sutureless versus conventional renorrhaphy

Primary outcome

Trifecta achievement

Effect

pooled risk ratio 1.17 (95% CI 0.97-1.41), I-squared 86.5%; randomised trial 0.97 (0.92-1.04), propensity-matched 1.26 (1.05-1.52); perioperative eGFR mean difference -3.89 (-6.16 to -1.62), no difference at 3 months

Routine suturing of the renal parenchyma after partial nephrectomy is done to secure haemostasis and close the collecting system, at the cost of compressing and devascularising the tissue being preserved. This meta-analysis pooled four comparative studies of 787 patients undergoing purely off-clamp robot-assisted partial nephrectomy, one randomised trial and three propensity-score-matched studies, with Trifecta achievement as the primary outcome.

Overall there was no significant difference in Trifecta achievement, risk ratio 1.17 (95% CI 0.97 to 1.41), with substantial heterogeneity at I-squared 86.5%. The two study designs disagreed, which is what drove that heterogeneity: the propensity-matched studies favoured the sutureless approach, risk ratio 1.26 (95% CI 1.05 to 1.52), while the randomised trial gave 0.97 (95% CI 0.92 to 1.04), meeting its non-inferiority criterion without showing superiority. The sutureless approach was associated with a smaller perioperative fall in eGFR, mean difference -3.89 (95% CI -6.16 to -1.62), but eGFR at three months did not differ. Major complications, transfusion and positive surgical margins were similar.

The disagreement between designs is the instructive part. In propensity-matched series the surgeon decides during the operation whether to suture, and that decision follows how the case is going, so easier cases are more likely to end up in the sutureless group. Randomisation removes that, and the effect disappears.

For a nephrologist advising a patient with a renal mass, the message is modest: this is a technique choice with equivalent short-term function, not a way to preserve kidney function. The perioperative eGFR advantage did not persist to three months, and the review is explicit that urinary complications, long-term function and oncological outcomes remain unresolved.

• Do not present a sutureless technique to patients as better preservation of kidney function; the early eGFR difference had gone by three months
• Treat propensity-matched surgical comparisons cautiously where the treatment decision is made intraoperatively
• Ask about baseline eGFR, solitary kidney and tumour complexity, which matter more to long-term function than the closure technique
• Arrange follow-up kidney function after any partial nephrectomy regardless of technique
• Note that urinary and vascular complications were sparsely reported and remain unresolved

The statistics, in plain English

An I-squared of 86.5% means the studies disagreed substantially, so the pooled risk ratio of 1.17 is an average across genuinely different results rather than a summary anyone should quote. Splitting by design explains it, and when a randomised trial and observational studies disagree this cleanly, the randomised estimate is the one to believe. Note also what non-inferiority means: the trial's interval of 0.92 to 1.04 stayed within its prespecified margin, which is a claim that the technique is not meaningfully worse, not a claim that it is equally good in every respect. The eGFR mean difference of -3.89 mL/min was measured perioperatively, when fluid shifts and analgesia move creatinine anyway, and it did not persist.

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