Penetrating renal injuries account for 5 to 29 percent of all kidney traumas.1 Although there is some heterogeneity in the data, studies suggest that most penetrating renal injuries are the result of gunshot wounds (83 to 86 percent).1-3 Last month’s Bulletin article outlined the importance of suspecting, diagnosing, and treating renal knife wounds, and the framework remains the same when thinking about gunshot wounds to the kidney.4
Unique pathology
However, projectile injuries to the kidney are unique in their pathophysiology and amount of destruction. Unlike stab wounds, the damage from projectiles affects organs other than the object itself.1,5 With respect to renal trauma, bullets are classified as either high-velocity projectiles, such as a rifle round, or low-velocity, found in handguns.1 Higher-velocity bullets often create temporary cavitation of energy along their path, which collapses and creates a shearing force on the surrounding tissues.1,5 Consequently, projectile injuries are rarely isolated to single organs.
With the higher risk for multiple organ injuries, as well as the difficulty in estimating their ballistic damage, penetrating renal trauma was previously considered an absolute indication for renal exploration.1 With improvements in imaging, as well as nonoperative protocols, this expectation has been relaxed.1,3 However, despite the advancements in nonoperative management, the rates of nephrectomy, failure of angioembolization, and multiple organ injuries were higher in projectile injuries to the kidney when compared with blunt trauma.
A fatal injury
To examine the occurrence of patients with gunshot wounds to the kidneys, the National Trauma Data Bank® (NTDB®) research admission year 2017 medical records were searched using the International Classification of Diseases, 10th Revision Clinical Modification codes. Specifically searched were records that contained one of 192 nonwar-related E codes for penetrating injury and a diagnosis code S37.0 (injury of the kidney). A total of 1,637 records were found, of which 1,439 records contained a discharge status, including 937 patients discharged to home, 238 to acute care/rehab, 40 to law enforcement, and 33 to skilled nursing facilities; 191 died (see Figure 1). Of these patients, 91 percent were men, on average 30.4 years old, had an average hospital length of stay of 13.3 days, an intensive care unit length of stay of 8.0 days, an average injury severity score of 25, and were on the ventilator for an average of 5.7 days. Of those tested for alcohol, 32 percent (314 out of 982) tested positive.
Figure 1. Hospital Discharge Status
