JOURNAL CLUB: Incidence of Urinary Leak and Diagnostic Yield of Excretory Phase CT in the Setting of Renal Trauma.

Abstract

The purpose of this article is to calculate the incidence of urinary leak, at both admission and delayed presentation, in the setting of blunt or penetrating renal trauma, and to determine the diagnostic yield of 5-minute excretory phase images on admission CT. Renal injuries were retrospectively identified from the trauma registry at an urban level I trauma center over a 6-year period. Follow-up imaging and clinical and surgical notes were reviewed and served as the aggregate reference standard. The total incidence of urinary leak, diagnostic yield of 5-minute-delayed admission CT scan, and the incidence of missed urinary leak not identified on admission 5-minute-delayed scan were calculated. There were a total of 431 renal injuries in 413 patients, of whom 201 patients (48.7%, including 60.8% of patients with grade IV or V injuries) underwent delayed phase imaging at admission, yielding 25 patients with 26 urinary leaks (all grade IV or V injuries). The incidence of urinary leak in grade IV or V injuries was 26.8%. One patient had a delayed diagnosis of urinary leak 36 hours after the initial CT scan, which did not show a urinary leak (0.23% of the total, or 1.0% of all high-grade renal injuries). The incidence of urinary leak after blunt or penetrating renal trauma was 6.1% and was seen in 26.8% of grade IV and V injuries. Admission excretory phase CT identified urinary leaks in 96% of patients. The incidence of delayed diagnosis of urinary leak is low.