The Experimental Study Of Maxillofacial Injury Associated With Craniocerebral Injury

Maxillofacial injury is common in our clinic work. Maxillofacial impact injury usually took place in time of peace; Maxillofacial fire-arm injury, especially explosive injury always took place in wartime. Maxillofacial region is closed to brain, so maxillofacial injury is often associated with brain injury, at the same time, severe brain injury is the main reason of the death to maxillofacial traumatic patients. But the researches in traumatic characteristics and damage mechanism have not been reported. To study the damage mechanism of maxillofacial injury associated with craniocerebral injury and changes of pathology, physiology, and function after injury, an animal model of maxillofacial impact injury associated with craniocerebral injury and an animal model of maxillofacial explosive injury associated with craniocerebral injury are established by the BIM- II type biological impact machine and a new spherical explosive. Life system changes after impact was monitored. The maxillofacial and brain injuries were examined. Craniptomy was done to animals of impact injury 6 hours after damage, however it was done to animals of explosive injury in different time point(l hour, 24 hours, 72 hours, 7 days, 14 days after damage). The pathological characteristics of corelative tissues were examined in detail under light and electron microscopes. The content of LPO, SOD, NO in soft tissue, brain, blood, and cerebral water content were measured, compared with control. The distribution and tissue location of NOS were studied by histochemistical and immunohistochemistic methods. Their relationship was studied to assess the pathological and physiological characteristics of maxillofacial injuries and brain damage associated. Recording the biomechanics respond data duringdamage and studying the characteristics of maxillofacial injury and brain damage associated and their relationship with biomechanics parameters and damage mechanism. The main purpose is to find out their clinic significance and provide experimental basics to further research work of trauma prevention and cure.The result indicated that:The BIM- II type biological impact machine and the spherical explosive can be easy controlled so that the damage energy can be repeated and standardization. Actual condition was truly simulated by the free situation of experimental animal. Damaged point could be selected, different kinds of maxillofacial injury and brain damage associated could be caused. These 2 animal models could be used in researches of damage mechanism and trauma prevention and cure of maxillofacial injury and brain damage associated.The content of LPO in blood, soft tissue, brain and NO in soft tissue, brain significantly increased with the severity of morphologic changes of local damaged tissue, edema of brain. Free radicals and NO are involved in the progress of tissue injury followed by maxillofacial impact and explosive injury. Cerebral NOS positive cells' expression increased with the progressive severity of craniocerebral injury, especially iNOS expression and the expression obviously possesses time dependency. iNOS distributed mainly inside nerve cells, the distribution was coincident with morphologic changes and increasing NO content of local damaged brain tissue.As the reaction of body, production of NO in blood was inhibited and production of SOD in blood was activated. The content of SOD in soft tissue and brain reduced with the severity of morphologic changes of local damaged tissue because a great deal of free radicals consumed SOD in local damaged tissue.The primary reason of maxillofacial injury associated with brain injury is the difference of velocity of brain and skull. It is the difference that cause relative movement between brain and skull and then cause contusion andlaceration of brain. On the other hand, stress could be transmitted to brain through direct connection of maxila and base of skull, it is also an important reason of maxillofacial injury associated with craniocereb'ral inj...