Introduction: Urinary extravasation (UE) is a main criterion for grade IV renal trauma. An appropriately-timed excretory phase CT is needed for accurate diagnosis. We aimed to assess the compliance with excretory phase imaging in a multi-center study and evaluate the management of UE after high-grade renal trauma (HGRT). Methods: We used HGRT data from 7 Level-1 trauma centers. Patients with CT scans were included. Demographics, injury and imaging characteristics, and interventions were reviewed. We assessed compliance with obtaining excretory phase CT and its timing (9 minutes delay considered as adequate), and the rate of interventions for UE. We defined UE information as Ux (unknown/excretory imaging not done), U0 (no UE in excretory imaging), and U1 (UE present). Results: We reviewed data from 550 patients with HGRT (grades III: 284 [51.5%]; IV: 250 [45.5%]; V: 16 [3%]) according to the 2018 AAST grading system. Only 324 (59%) had excretory phase images available within the initial CT to assess for UE with compliance rates between 26% to 100% between different centers. The median time between the arterial and delayed phase was 8 minutes (IQR: 4–11); 51% of the excretory images were inadequately timed ( <9 minutes). Overall, 94 (17%) were diagnosed with UE either initially (n=62) or in follow up images (n=32). Of these, 22 (23%) underwent ureteral stent placement and 5 (5%) received peri-renal drains. Of the 262 with U0, 21 had UE diagnosed in follow up studies (8% missed UE with initial excretory imaging). Of the 226 with Ux, 11 were diagnosed with UE in follow up imaging (5% missed UE without initial excretory imaging). 59 of 94 patients with UE (63%) would have been grade IV only due to UE. Compared to the other patients with UE, these had lower rates of bleeding interventions (8% vs. 31%), active bleeding, and had smaller hematoma and lacerations sizes. Conclusions: About 40% of those with HGRT did not undergo excretory phase imaging in the initial assessment. The compliance in obtaining these images and the timing were variable and suboptimal. These can lead to inaccurate and incomplete grading of renal injuries in regards to UE. UE status can be provided as separate information or be included under grade III renal injuries. SOURCE OF Funding: None
