Importance of delayed imaging for blunt renal trauma.

The advent of noninvasive computed tomography of the abdomen and pelvis for evaluation of blunt renal trauma has led to the practice of expectant management for hemodynamically stable patients. Although expectant management of higher grade injuries (American Association for the Surgery of Trauma Renal Injury Scale) would intuitively result in an increased frequency of urologic complications, this has not been previously examined in a large series of patients utilizing contemporary radiologic imaging techniques. A retrospective review of patients from a single institution within a recent 4-year period revealed 4 grade I, 13 grade II, 21 grade III, 7 grade IV, and 4 grade V injuries. None of grade 1, 15% of grade II, 38% of grade III, 43% of grade IV, and 100% of grade V injuries had one or more (15 major and 11 minor) urologic complications. The incidence of urinary complications correlated significantly with increasing grade (0%, 15%, 38%, 43%, and 100% for grades I to V, respectively; r = 0.94, p = 0.0158). Of the delayed urologic complications, 50% were diagnosed on follow-up imaging studies and 33% of them required intervention. Therefore we advocate repeat imaging 2 to 4 days after trauma resulting in grade III to V blunt renal lacerations to identify delayed complications that may require intervention.