The Effects of Gunshot Wound of Extremities on Peripheral Nerves in Dogs / 第三军医大学学报

ABSTRACT

The effects of the temporary cavities and pressure waves of peripheral nerves were studied following 5.56mm and 7.62mm bullets shooting the soap block and both thighs of dogs. The studies indicated that there was an exponential regression correlation among the displacement and stretching ratio of nerves and temporary cavity, the maximum of pressure peak(MPP), and energy absorption (EA). The degree of nervous injuries depended on the temporary cavity volume and amounts of EA. The amounts of EA of 5.56mm bullets were 40.67kg?m,2.5 times as much that of 7.62mm bullets.MPP of 5.56mm bullets was 1.8 times as of 7.62mm.This suggested that the nerve injuries caused by 5.56mm bullets were more severe than of 7.62mm bullets. Pathological examination showed that the microstructure of nerves was damaged though the microstructure unchanged. Fibre-broken-up, bleeding in perineurium, deformation of axon, mitochondria swelling and axon membrane dividing from its myelin sheath could be seen. In 5.56 bullet wounding group the potential latency was prolonged and the amplitude decreased remarkedly. This indicated that the nerves were only damaged partially. In early management it is important to release intraneural pressure, remove the hematoma in the fascia to recover microcirculation.