The Impact of Delayed-Phase Imaging at Admission on the Management of Urinary Extravasation in High-Grade Renal Trauma

Purpose: American Urological Association Urotrauma guidelines recommend delayed-phase imaging on presentation for all renal injuries, although data to support it are anecdotal. Forgoing delays risks unrecognized collecting system injuries. We hypothesized that renal trauma patients without admission delays have more complications from urinary extravasation. Materials and Methods: From 2005 through 2020, 1,751 renal trauma patients were identified from our institutional trauma registry. Included patients had an estimated American Association for the Surgery of Trauma renal injury grade of IIIeV and a perinephric fluid collection. Propensity scores for receipt of delayedphase imaging were calculated based on Injury Severity Score, arrival condition, admission systolic blood pressure, sex and renal injury grade. Propensity scoreadjusted logistic regression was used to compare clinical outcomes between those with and without admission delays. Results: Ninety (28.6%) of 315 included patients had delays on presentation. Patients without delays had higher Injury Severity Scores (29 vs 23, p=0.002), fewer isolated renal injuries (27.6% vs 38.9%, p=0.05) and lower grade renal injuries (56.9% vs 41.1% grade 3, p=0.03). After propensity score adjustment, patients with delays were more likely to undergo immediate interventions (OR 11.75, 95% CI 2.99-78.10) and interval stent placement for urinary extravasation (OR 6.86, 95% CI 1.56-47.64) without a difference in urological complications (OR 5.07, 95% CI 0.25-766.16). Conclusions: Delayed-phase imaging was associated with an increased odds of undergoing immediate and asymptomatic interval urological interventions without a difference in the odds of a complication after high-grade renal trauma. Post-trauma urinary extravasation requires further research to determine which patients require imaging and intervention.