Utility of MDCT findings in predicting patient management outcomes in renal trauma.

PURPOSE: The purpose of this study is to assess the utility of computed tomography (CT) in predicting clinical outcomes in renal trauma.

MATERIALS/METHODS: This retrospective study was IRB approved and HIPAA compliant; informed consent was waived. One-hundred-sixty-two, trauma-related renal injuries (157 adults) from January 01, 2006 to December 31, 2013 were included in this retrospective study. CT findings of vascular and collecting system (CS) injuries were recorded, and American Association for the Surgery of Trauma (AAST) renal injury grades were assigned. Fisher's exact test evaluated correlations between AAST grade and active hemorrhage, AAST grade and surgical/endovascular therapy, active hemorrhage and surgical/endovascular therapy, and size of perinephric hematomas and CS injuries. The unpaired t test correlated to the size of perinephric hematomas in CS injuries diagnosed on initial versus repeat imaging.

RESULTS: AAST grades were as follows: 120 grades I-III and 42 grade IV/V. Active hemorrhage was diagnosed in 25 (15%) patients and CS injury in 22 (14%) patients. Seven (8%) patients received surgical/endovascular therapy. There were statistically significant correlations between AAST grade and active hemorrhage (p = 0.003), active hemorrhage and surgical/endovascular therapy (p < 0.0001), and large perinephric hematomas (>2 cm) and CS injuries (p < 0.0001). There was no significant correlation between AAST grade and surgical/endovascular therapy (p = 0.08). Of the CS injuries (50%), 11/22 had no evidence of CS injury on initial imaging, being detected on follow-up CT. These "masked cases" demonstrated significant differences in perinephric hematoma size when compared to CS injuries diagnosed on initial imaging (p = 0.01).

CONCLUSION: Active hemorrhage in renal trauma is a significant predictor of surgical/endovascular therapy, in contradistinction to the AAST grade. In collecting system injuries, a large fraction was not detectable on initial CT, supporting the need for repeat imaging in cases with large perinephric hematomas.