Characteristics and mechanism of lower limb injury induced by landmine blast: A research in a rabbit model.

BACKGROUND: Limb injuries caused by landmine explosions are tricky to treat and difficult to protect. It is necessary to establish an animal model for studying lower limb injury and to investigate the characteristics and mechanisms of lower limb injury induced by landmine blasts.

METHODS: Twenty-six mature white rabbits were randomly divided into sham group (n=10) and injury group (n=16). Landmine blast was simulated by electric detonators under the right lower limb in upright state by a special modified fixation frame. High-speed photography was used to observe the body movements. Vital signs, vascular injury (determining by digital subtraction angiography), pathological characteristics, and ATP concentration of the tibialis anterior muscle and triceps surae of shank were recorded for com-parison.

RESULTS: Generally, middle and lower segment of the injured legs of the rabbits was seriously damaged. The limb stump presents a distribution of three areas, tissue free zone, contusion hematoma, and edema contusion. Sneak wound track, myofascial destruction, and periosteum stripping were typical characteristics of landmine blast injury. ATP concentration and pathological analysis showed that the tibialis anterior muscle was the most seriously injured, followed by the gastrocnemius and soleus. ATP concentration of affected muscle of both the contusion and commotio area declined remarkably over time, but the muscle in the avulsion area stayed at a low activity level with no change over the time. Small vascular injury in the contusion area was evident. The site of the sciatic nerve lesion was higher than the muscle. Injured site of sciatic nerve injury was higher than serious contusion muscle. High-speed photography demonstrated that the joints of the injured limb extremely flexed followed by a rapid stretch under the blast shock wave.

CONCLUSION: The established experimental model presents typical effect of lower limbs wounded by the mine blast in war field. Landmine blast can cause typical damage on lower limbs including nerve lesion, knee injury, and microcirculation damage that is pro-gressive over time. The limb stump is divided into three zones based on gross pathology and micropathology, which can provide an important reference for clinical treatments and prognosis.