• AAST injury scale
• Computed Tomography
• CT
• Renal trauma

Objectives. The purpose of our study is to assess the role of multidetector computed tomography (MDCT) in predicting therapeutic management and clinical outcomes of patients with renal trauma in terms of statistical significance. Furthermore, the work aims to analyze the current effectiveness of the American Association for the Surgery of Trauma (AAST) injury scale as a severity grading system and indicator for operative/non-operative approach.

Materials and methods. The study includes sixty-one polytraumatized patients admitted to the Emergency Department of Pisa from January 2013 to March 2017 that underwent a MDCT examination with diagnosis of renal trauma. CT features were retrospectively evaluated and ranked according to the revised AAST injury scale, with a final grade assignment to each renal trauma; findings like vascular contrast extravasation (active hemorrhage) and contained vascular injuries (pseudoaneurysm) were also recorded. The chi-squared test was used to determine the statistical correlation between AAST renal injury grade and the need for operative (surgical/endovascular) management, CT findings of active hemorrhage/pseudoaneurysm and the need for operative (surgical/endovascular) management, AAST renal injury grade and CT findings of active hemorrhage/pseudoaneurysm.

Results. Renal trauma injuries were classified as low-grade and high-grade as follows: 39 (64%) AAST I-III and 22 (36%) AAST IV-V. The presence of active hemorrhage and/or pseudoaneurysm was found in 28/61 (45%) patients, of which 21 (75%) required surgical/endovascular intervention. Twenty-one out of 22 (96%) of renal injuries handled operatively showed active bleeding at CT examination (n = 12 low-grade; n = 9 high-grade). Statistical analysis demonstrated significant correlation (p value < 0,0001) between the presence of active hemorrhage/pseudoaneurysm and the need for operative management. On the contrary, no statistically significant association was found between the AAST grade and the need for operative management (p value = 0,251), and between the AAST grade and the presence of active hemorrhage/pseudoaneurysm (p value = 0,958).

Conclusion. Vascular CT findings, not mentioned in the AAST injury scale, represent an important added value in establishing the severity grade of traumatic renal injuries and the best approach to decide the appropriate therapeutic options. In contradistinction to the AAST grade, active vascular contrast extravasation and/or contained vascular injuries are significant predictor of the need for operative management.