Muscle devitalization in high-energy missile wounds, and its dependence on energy transfer

Relations between the energy transferred by a high-velocity missile along a wound channel and the ensuing tissue destruction were studied in 25 live, anesthetized pigs. They were wounded in the muscular parts of the hind legs by an assault rifle bullet or by a spherical steel ball at about 1,000 m/s. The penetration of the assault rifle bullets was recorded by a stereo, multichannel flash X-ray arrangement. The energy transfer in the wound was evaluated from the X-rays. The wounds were surgically debrided in sections by a skilled surgeon. The energy transfer of the spherical steel bullets was measured. These animals had the thigh surrounded with a plaster of Paris cast, in order to suppress, as far as possible, the formation of the temporary cavity. The wounds were debrided. The amounts of tissue debrided were weighed and utilized as a measure of the extent of the injury. Good and consistent correlations between energy transfer and tissue debridement were obtained for the wound types studied. The amount of tissue debrided diminished by about 40% for the plaster-covered animals. Influence of boundary effects could be studied, and the results give indications of the mechanisms of missile wounding.