Predictors of the need for nephrectomy after renal trauma.

BACKGROUND: Initial management of solid organ injuries in hemodynamically stable patients is nonoperative. Therefore, early identification of those injuries likely to require surgical intervention is key. We sought to identify factors predictive of the need for nephrectomy after trauma.
METHODS: This is a retrospective review of renal injuries admitted over a 12-year period to a Level I trauma center.
RESULTS: Ninety-seven patients (73% male) sustained a kidney injury (mean age, 27 +/- 16; mean Injury Severity Score, 13 +/- 10). Of the 72 blunt trauma patients, 5 patients (7%) underwent urgent nephrectomy, 3 (4%) had repair and/or stenting, and 89% were observed despite a 29% laparotomy rate for associated intraabdominal injuries in this group. Twenty-five patients with penetrating trauma underwent eight nephrectomies (31%), one partial nephrectomy, and two renal repairs. Regardless of the mechanism of injury, patients requiring nephrectomy were in shock, had a higher 24-hour transfusion requirement, and were more likely to have a high-grade renal laceration (all p < 0.05). Bluntly injured patients requiring nephrectomy had more concurrent intraabdominal injuries (p < 0.0001). Overall, patients after penetrating trauma were more severely injured, had higher 24-hour transfusion requirements, and a higher nephrectomy rate (all p < 0.05). Despite a higher injury severity in the penetrating group, however, mortality was higher in the bluntly injured group (p < 0.0001). Univariate predictors for nephrectomy included: revised trauma score, injury severity score, Glasgow Coma Scale score, shock on presentation, renal injury grade, and 24-hour transfusion requirement. No patient with a mild or moderate renal injury required nephrectomy, whereas 6 of 12 (50%) grade 4 injuries and 7 of 8 (88%) grade 5 injuries required nephrectomy. Multiple logistic regression analysis confirmed penetrating injury, renal injury grade, and Glasgow Coma Scale score as predictive of nephrectomy.
CONCLUSION: Overall, injury severity, severity of renal injury grade, hemodynamic instability, and transfusion requirements are predictive of nephrectomy after both blunt and penetrating trauma. Nephrectomy is more likely after penetrating injury.