High-grade renal injury: non-operative management of urinary extravasation and prediction of long-term outcomes.

OBJECTIVE: To predict the outcomes of a non-operative approach to managing urinary extravasation after blunt renal trauma. PATIENTS AND METHODS: A prospective observational study was conducted between January 2004 and October 2011. First-line non-operative management was proposed for 99 patients presenting with a grade IV blunt renal injury according to the revised American Association for the Surgery of Trauma (AAST) classification. Among them, 72 patients presented with a urinary extravasation. Management and outcomes were recorded and compared between patients presenting and those who did not present with urinary leakage. Relative postoperative renal function was assessed 6 months after the trauma using dimercapto-succinic acid renal scintigraphy. Predictors of the need for endoscopic or surgical management and long-term renal function were evaluated on multivariate analysis. RESULTS: Among patients with urinary leakage, endoscopic ureteric stent placement and open surgery were required in 37% and 15%, respectively. On multivariate analysis, fever of >38.5 °C and ureteric clot obstruction were independent predictors of the need for ureteric stent placement. The only predictor of open surgery was the percentage of devitalised parenchyma. Long-term renal function loss was correlated to the percentage of devitalised parenchyma and associated visceral lesions. Urinary extravasation did not predict surgical intervention or long-term renal function loss. CONCLUSIONS: Urinary extravasation after blunt renal trauma can be successfully managed conservatively and does not predict long-term decreased renal function or surgery requirement. A devascularised parenchyma volume of >25% predicts a higher rate of surgery and poorer renal function.