Urban free falls and patterns of renal injury: a 20-year experience with 396 cases.

OBJECTIVE: To determine the distribution and stage of renal injuries from free falls and to determine the appropriate methods for their evaluation and management.
MATERIALS AND METHODS: We reviewed the records of 423 patients with renal injuries after a fall from height. Twenty-seven patients did not survive their injuries and were removed from the study.
RESULTS: Based on the American Association for the Surgery of Trauma grading scale, 372 of the renal injuries (94%) were grade 1, whereas 24 injuries (6%) were grade 2 to 4. None of the injuries was grade 5. Of the patients with grade 2 to 4 renal injuries, nine patients had grade 2, three patients had grade 3, nine patients had grade 4, and one patients had a forniceal rupture, as well as two patients with ureteropelvic junction disruptions (one bilateral), four with segmental vascular injuries, and two with hilar vessel injuries. Mean height of free fall was 23.1 feet (range, 10-60 feet) and mean Injury Severity Score was 20.6. Neither the degree of renal injury nor the Injury Severity Score statistically correlated to the height of the free fall. Patients with grade 2 to 4 were more likely than patients with grade 1 renal injuries to be in shock and to have intra-abdominal injuries, gross hematuria, and higher Injury Severity Score(33%, 34%, 62%, 24.6 vs. 6%, 9%, 14%, 20.1, respectively). The degree of hematuria and the grade of renal injury, however, did not correlate. Grade 2 to 4 renal injuries had microscopic hematuria and no shock in 8.3% (2 of 24 patients) and no hematuria in 20.8% (5 of 24 patients). Thus, standard selection criteria for renal imaging of blunt trauma, namely gross hematuria or microhematuria and shock would have missed 7 or 29% of our grade 2 to 4 renal injuries, or 1.8% of all grade 1 to 4. Half of the patients with grade 2 to 4 renal injuries had associated multiple-system injuries, and half had flank ecchymosis or tenderness. Of the patients with grade 2 to 4 injuries, 9 patients (37%) underwent surgical exploration and repair of injury. All renal units were preserved and underwent successful reconstruction. Six of the nine patients initially were explored because of associated intra-abdominal injuries. No major urological sequelae were noted postoperatively or in follow-up of all renal injuries.
CONCLUSION: The height of the free fall cannot reliably predict the degree of the resulting renal injury. Despite the absence of hematuria or shock, vertical deceleration injuries, in particular those associated with multiple-system injuries and/or physical signs of potential renal injury (e.g., flank ecchymosis), demand renal imaging. After a fall from height, the ureteropelvic junction and renal vasculature should also be imaged for potential injury.