Biomechanical changes in the head associated with penetrating injuries of the maxilla and mandible: an experimental investigation.
OBJECTIVE
In this experiment, we studied the craniocerebral injury that occurs due to the transmission of forces when maxillofacial gunshot wounds are sustained by the facial bones and cranium.


METHODS
Forty fresh pigs' heads were wounded by one of the following methods: steel spheres weighing 1.03 g at an impact velocity of 1,400 m/s, steel spheres weighing 1.03 g at an impact velocity of 800 m/s, M193 military bullets, or M56 military bullets. Pressure waves in the brain, acceleration of the head, and stress changes in the facial bones and cranium at the moment of the impact were recorded by pressure and acceleration transducers and strain gauges and were statistically compared.


RESULTS
Some obvious differences between the mechanical values obtained from high-and low-velocity missile wounds were found. A negative relationship between the peak value of the pressure wave in the brain and the distance from the point of impact to the transducer was obtained. The acceleration of the head in the direction of the ballistic path was the strongest in absolute value. There were differences in the stress values between the mandible and the temporal bone.


CONCLUSIONS
Acceleration of the head, pressure wave changes in the brain, and injury from bony stress conduction all play important roles in associated craniocerebral damage after maxillofacial firearm wounds.
Tan
Yinghui
Y
Department of Oral and Maxillofacial Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing, PR China. tanyh1962@yahoo.com.cn
Zhou
Shuxia
S
Jiang
Hetian
H
D000054:Acceleration; D000818:Animals; D001696:Biomechanical Phenomena; D001930:Brain Injuries / Q000209:etiology / Q000503:physiopathology*; D020197:Head Injuries, Penetrating / Q000503:physiopathology*; D007427:Intracranial Pressure; D008446:Maxillofacial Injuries / Q000150:complications*; D013314:Stress, Mechanical; D013552:Swine; D014732:Vibration; D014948:Wounds, Gunshot / Q000503:physiopathology*