| Vol. 3, Issue 2, Article 1 |
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Meagher, Shah. |
People own guns for a myriad of reasons, including hunting, sport shooting, and collecting. Guns are also owned, at least in part, for self-defense. Fear of crime is widespread, and many consider keeping a gun in the home a reasonable precaution. Forty percent of American homes contain one or more firearms. Studies show that people who keep guns for self-defense are more likely to keep at least one gun loaded and unlocked than people who keep guns for other purposes.
The United States leads industrialized nations with the highest numbers and rates of firearm deaths. Each year, firearms cause approximately 38,000 deaths and 99,000 non-fatal injuries in the U.S. The incidence of penetrating head injury in the United States is about 12 per 100,000 population, the highest of any developed country in the world.
In the United States, firearms are the implement of choice for the commission of both homicide and suicide, and the favored target is the craniofacial region.
Initial patient selection was performed using a computerized search of the database cataloging University of Michigan CT examinations. The keywords used were "gunshot", "gun", "shotgun", "bullet", "face", "maxillofacial", "orbits", "cranium", and "brain". The search was limited to head, maxillofacial, orbital, and neck CT's performed at the University of Michigan between January of 1998 and December of 2002. A total of 39 patients were identified. The caseload was then examined and patients with gunshot injuries to the face and cranium were retained while patients with gunshot injuries solely to the neck were excluded. Patient electronic medical records were then examined retrospectively to identify lethality, the firearm used, the location of the injury (including entry and exit sites), the place at which the injury occurred (home, etc.), and existence of co-morbid factors.
Injuries were stratified into one of four categories: accidentally self-inflicted, intentionally self-inflicted, accidentally inflicted by another, and intentionally inflicted by another. Pertinent imaging studies were reviewed and representative examples of various injuries photographed. Detailed 3D reformats and reconstructions of these injuries were created using a GE Advantage 4.0 workstation. The "Reformat", "SolidFacial", and "CT Soft" reconstruction algorithms were employed.
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Figure 1, A-C: LEthal intentionally self-inflicted handgun injury. Right temporal entry wound and left parietal exit wound. Reformatted paraxial image traces the path of the bullet, outlined by hemorrhage, bone fragments and vapor bubbles. Massive edmea with poor grey-white differentiation and sulcal effacement is seen. There are subdural, intraparenchymal, and inraventricular hemorrhages with pneumocephalus and blood in the interhemispheric fissure.
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Figure 2, A-C: Lethal close-range handgun injury intentionally inflicted by another. Right frontal entry wound. Bone fragments, vapor bubbles, bullet fragments, and hemorrhag are left in the bullet's wake. The bullet is lodged in the fractured left frontal bone. Massive edema with basal cistern effacement and transtentorial coning is identified. Massive edema and coning were seen in all cases of lethal close-range handgun injury where bullet penetrated the skull and traveled through brain parenchyma.
39 patients were identified with gunshot injuries to the face and cranium. Of the 39 cases, 20 were intentionally self-inflicted, 16 were intentionally inflicted by another, 1 accidentally inflicted by another, and 2 had no pertinent information to determine who inflicted the injury. Of 20 intentionally self-inflicted injuries, 12 were by handguns, 5 by shotguns, 2 by rifles, and 1 by BB gun. Of 16 injuries intentionally inflicted by another, 14 involved handguns and 2 involved shotguns. The sole accidental injury inflicted by another was a non-lethal hunting accident involving a shotgun. For the 2 unknowns, 1 involved a handgun and 1 a BB gun.
13 fatalities occurred among the 39 patients. 7 of 20 intentionally self-inflicted injuries were fatal, all employing handguns. 5 of 16 injuries intentionally inflicted by another were fatal, again, all involving handguns. 13 of 20 self-inflicted injuries were non-lethal: 5 used handguns, 5 used shotguns, 2 used rifles, and 1 used a BB gun. 11 of 16 injuries intentionally inflicted by another were non-lethal: 9 involved handguns and 2 involved shotguns. Of 2 unknown cases, 1 was lethal (handgun) and 1 was not (BB gun).
All fatalities resulted from handguns. No shotgun or rifle injuries were lethal. All 7 patients with intentionally self-inflicted shotgun and rifle blasts devastated facial soft tissue and bone. Injury extent was determined, at least in part, by position of the muzzle inside the mouth or under the chin.
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Figure 3, A-C: Long-range handgun injury intentionally inflicted by another. There is no skull penetration. Bullet deforms primarily against the petrous temporal bone. There is a depressed fracture of the right parieto-occipital bone above the petrous region with countercoup contusion and a small subdural hemorrhage in the left frontal region. No brain edema is identified.
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Figure 4 A-C: BB gun injury, accidentally self-inflicted. Trace the path of the BB through the right eye with ruptured orbital globe demonstrating irregular contour, vapor bubbles, and vitreous hemorrhage. The low-velocity BB penetrated the right orbital roof, stopping at the base of the right front lobe. No brain edema or intracranial hemorrhage is identified.
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