We now know that most patients with blunt renal injury will not require surgery, and most will not require any intervention whatsoever [1–3]. The brave new world of non-operative management of renal trauma is to understand just which patients with high-grade renal trauma will require acute or delayed intervention. The above paper advances our understanding of this difficult question in some important ways:

Urinary extravasation by itself is a benign condition that usually does not require intervention. Only 37% of patients with urinary extravasation required stents and it is possible that as these authors treated some asymptomatic patients that this number should be even lower. Further, urinary extravasation alone did not predict the need for open surgical intervention in this study.

Vigilance is still required in an initially non-operative approach. Initially non-operative treatments are referred to as an ‘expectant’ approach by some for this reason. In this series, 11% of those managed non-operatively ultimately required open surgical intervention (a number that matches other similar series). In all, 14% required angioembolisation. Expectant management does not mean no management.

Fever and ‘clot obstruction’ were important predictors of those requiring stents.

Patients with devitalised parenchyma, indeed, do poorer than other patients. This has been proposed before by Moudouni et al.[4]. Devitalised parenchyma estimated to be >25% of the kidney on CT was associated with a three-fold increase in the need for angioembolisation, and a nearly two-fold increase in the need for open surgical intervention. Patients with large areas of devascularisation also had a four-fold decrease in relative renal function: 40% in those with <25% devitalised parenchyma to 10% in those with >25%.

Angioembolisation seems to be an appropriate initial treatment method of choice for those with clinically significant renal bleeding. It was used in 25 patients compared with renorrhaphy/nephrectomy, which was required in 15. I will emphasise that angioembolisation should be performed in a timely fashion, by well-trained practitioners and may not be preferable to immediate open surgery in those who are exsanguinating from the kidney.

We need to continue to save kidneys after trauma by observing them instead of rushing to surgically explore them (at a high risk of nephrectomy). We also need to continue to save patients by not observing those who are bleeding to death from their kidneys, in favour of speedy, expert angioembolisation, attempted renorrhaphy, and only rarely nephrectomy.