Analysis of ballistic trajectories and its association with clinical outcomes in civilian penetrating brain injury.

Purpose: Civilian penetrating brain injuries (PBI) caused by firearms are a medical emergency with high rates of morbidity and mortality. The aim of this study was to evaluate the association between trajectory vectors in CT brain angiography and clinical outcomes in patients with civilian gunshots.

Methods: This is a retrospective analytical cross-sectional study that includes patients over 15 years of age with PBI due to firearms, admitted from January 2019 to December 2021 at a University Hospital in Cali, Colombia. A brain CT with angio-CT was performed the first day of admission. An XYZ coordinate system centered on the Turk's saddle was developed. Trajectories of projectiles were plotted and compared to a patient 0 in a 3D-Slicer software. A bivariate analysis of the clinical and geometric characteristics of the trajectory was performed. Primary outcomes include mortality and disability at 6 months.

Results: Twenty-eight patients with a mean age of 27.39 ± 11.66 years were included. The vectors of non-survivors show a trend, crossing at a specific area. This area was designated as a "potential lethal zone" and inside this area, injuries around 25.3 mm from the circle of Willis, were associated with greater mortality (p < 0.005).

Conclusions: In our study PBI avoiding the ventricular system, brain stem, dorsum sellae and the circle of Willis were associated with more survivability. A "potential lethal zone" was detected and associated with poor outcome after civilian PBI due to firearms. A better evaluation of the performance of this "potential lethal zone" in larger studies will be required.