Should blunt segmental vascular renal injuries be considered an American Association for the Surgery of Trauma Grade 4 renal injury?

Abstract

Background: Renal segmental vascular injury (SVI) following blunt abdominal trauma is not part of the original American Association for the Surgery of Trauma (AAST) renal injury grading system. Recent recommendations support classifying SVI as an AAST Grade 4 (G4) injury. Our primary aim was to compare outcomes following blunt renal SVI and blunt renal collecting system lacerations (CSLs). We hypothesize that renal SVI fare well with conservative management alone and should be relegated a less severe renal AAST grade.

Methods: We retrospectively identified patients with SVI and G4 CSL admitted to a Level 1 trauma center between 2003 and 2010. Penetrating trauma was excluded. Need for surgical intervention, length of stay, kidney salvage (>25% renal preservation on renography 6-12 weeks after injury), and delayed complication rates were compared between the SVI and CSL injuries. Statistical analysis used χ, Fisher's exact, and t tests.

Results: A total of 56 patients with SVI and 88 patients with G4 CSL sustained blunt trauma. Age, Injury Severity Score (ISS), and length of stay were similar for the two groups. Five patients in each group died of concomitant, nonrenal injuries. In the G4 CSL group, 15 patients underwent major interventions, and 32 patients underwent minor interventions. Only one patient in the SVI group underwent a major intervention. The renal salvage rate was 85.7% following SVI versus 62.5% following CSL (p = 0.107).

Conclusion: Overall, surgical interventions are significantly lower among the SVI cohort than the G4 CSL cohort. Further analysis using a larger cohort of patients is recommended before revising the current renal grading system. Adding SVI as a G4 injury could potentially increase the heterogeneity of G4 injuries and decrease the ability of the AAST renal injury grading system to predict outcomes, such as nephrectomy rate.

Level of evidence: Epidemiologic study, level IV.

Figure 1

(a) Arterial phase of transverse CT scan revealing a left segmental vascular renal injury (arrow). The CT was performed at the time of presentation to the emergency department. A collecting system injury was not present, as here was no evidence of contrast extravascular on subsequent delayed imaging. Follow up imaging 48 hours later was negative for collecting system injury. (b) Delayed imaging from transverse CT scan of a right renal segmental vascular injury (arrow) 48 hours after blunt abdominal trauma. The CT scan was performed to assess for renal injury progression using a low-dose radiation protocol.