Gunshot wounds: Radiology and wound ballistics

The G2 research R.I.P. fragmenting bullet-radiographic features of a recently encountered projectile

Gunshot wounds (GSWs) are an important cause of disability and death in the USA. Although radiography is limited in its ability to detect bullet types, a projectile introduced during the last decade, the R.I.P. bullet by G2 Research, consists of a base slug connected to 6 to 8 sharp trocars designed to diverge within soft tissue following impact, resulting in what we believe to be a unique imaging appearance that can be confusing to those not familiar with this particular projectile. Furthermore, this bullet is 100% copper, which may allow for safe imaging with magnetic resonance imaging if correctly identified prior to scanning.

Effects of Re-heating Tissue Samples to Core Body Temperature on High-Velocity Ballistic Projectile-tissue Interactions

Damage produced by high-speed projectiles on organic tissue will depend on the physical properties of the tissues. Conditioning organic tissue samples to human core body temperature (37°C) prior to conducting ballistic experiments enables their behavior to closely mimic that of living tissues. To minimize autolytic changes after death, the tissues are refrigerated soon after their removal from the body and re-heated to 37°C prior to testing. This research investigates whether heating 50-mm-cube samples of porcine liver, kidney, and heart to 37°C for varying durations (maximum 7 h) can affect the penetration response of a high-speed, steel sphere projectile. Longer conditioning times for heart and liver resulted in a slight loss of velocity/energy of the projectile, but the reverse effect occurred for the kidney. Possible reasons for these trends include autolytic changes causing softening (heart and liver) and dehydration causing an increase in density (kidney).

Firearms, bullets, and wound ballistics: an imaging primer

Based on its intrinsic mass and velocity, a bullet has an upper limit of wounding potential. Actual wound severity is a function of the bullet construction and trajectory, as well as the properties of the tissues traversed. Interpreting physicians must evaluate the bullet trajectory and describe patterns of injury resulting from the effect of energy transfer from the projectile into living tissue. A basic understanding of firearms, projectiles, and wound ballistics can help the interpreting physicians in conceptualizing these injuries and interpreting these cases.

Clinical update: gunshot wound ballistics

Although firearm related injury and mortality actually may be declining, gunshot trauma remains a significant cause of morbidity and socioeconomic cost with 115,000 missile injuries annually and as many as 40,000 deaths. Wounds typically are classified as low-velocity (< 2000 feet/second) or high-velocity (> 2000 feet/second). However, these terms can be misleading. More important is the efficiency of energy transfer, which is dependent on the projectile's physical characteristics including deformation and fragmentation, kinetic energy, stability, entrance profile, path traveled through the body, and the biologic characteristics of the tissues. Therefore, the decision whether to explore the wound should not be based solely on the involvement of a high-velocity or low-velocity weapon. The majority of low-velocity gunshot wounds can be treated safely nonoperatively with local wound care and outpatient treatment. Treatment of associated fractures generally is dictated by the bony injuries, which have similar personalities to closed fractures. Because contamination is not always apparent, routine antibiotic prophylaxis still is recommended. The soft tissues assume a more crucial role in high-velocity and shotgun fractures, whereas high-energy injuries and grossly contaminated wounds mandate irrigation, appropriate debridement, and the use of open fracture protocols. However, a patient with a high-velocity wound with limited soft tissue disruption, no significant functional deficits, no evidence of bullet fragmentation, and minimal bony involvement can be a candidate for simple wound care. When exploration is indicated, decompression and excision of necrotic tissue is the rule with color, consistency, contractility, and capacity to bleed providing valuable information regarding muscle viability.