High grade renal trauma: Does the mechanism of penetrating injury influence renal salvage rate?

Background Most of the data on high grade Traumatic renal injuries (TRI) has come from centres which predominantly encounter blunt trauma. Blunt and penetrating mechanisms are not analogous, and it is imprudent to blindly extrapolate management strategies between the two groups. In addition, within the broad group of penetrating mechanisms of injury there are also major differences between gunshot wounds (GSW) and stab wounds (SW). The aim of this comparative study of GSW and SW to the kidney is to quantify the impact of the mechanism of injury on nephrectomy rate in high grade TRI. Methods A prospective trauma registry was interrogated retrospectively. All patients sustaining a high grade (Grade III to V) penetrating TRI were included. The diagnosis was made either with cross-sectional imaging or intra-operative findings. The nephrectomy rate of the different mechanisms of penetrating (GSW vs SW) TRI was compared in each grade. Results A total of 28 GSW and 27 SW causing high grade TRIs (Grade III-V) were included over the 85 months of the study. GSW lead to a higher nephrectomy rate than SWs 50.0 vs 19%, (p = 0.023). When comparing grade for grade, Grade III: 20.0 (GSW) vs 21% (SW), (p = 1). Grade IV: 71 (GSW) vs 17%, (SW) (p = 0.058) and Grade V: 100 (GSW) vs 0%, (SW) (p = 0.28). When comparing Grade IV – V together, the difference is 85 (GSW) vs 15%, (SW) (p = 0.001). Conclusion On a grade to grade comparison GSWs have a much higher risk for nephrectomy than SW's in grade IV and V TRI. TRI secondary to GSWs appears to be an independent risk factor for nephrectomy in high grade injuries. The mechanism of penetrating TRI should be considered in future management algorithms and clinical approaches.