颌面部撞击伤伴发颅脑损伤的实验研究

目的 :研究颌面部撞击伤合并颅脑损伤的致伤机制和损伤特点。方法 :采用水平气动式撞击机分别以 4 77m/s± 0 5 3m/s(A组 )、9 16m/s± 0 6 5m/s(B组 )和 13 95m/s± 0 6 7m/s(C组 )的速度撞击兔左侧面中部 (n =6 )。观察致伤后动物的生命体征的变化 ,并对颌面部软组织、脑组织进行损伤的大体和光、电镜观察 ,测定致伤后 6h血清中脂质过氧化物 (LPO)、超氧化物歧化酶 (SOD) ,一氧化氮 (NO)的含量变化和脑含水量 ,同时记录致伤瞬间脑内压力和头颅冲击加速度。结果 :形态学改变低速和中速致伤组 (A和B组 )主要以局部损伤为主 ,高速致伤组 (C组 )则同时合并颅脑损伤。兔致伤后 6h血清中LPO、SOD值以及脑含水量C组显著高于A、B组 (P <0 0 5 ) ,而NO值明显低于A、B组 (P <0 0 5 )。头颅加速度和颅内压峰值C组均明显高于A、B两组 (P <0 0 5 )。结论 :致伤瞬间头颅冲击加速度响应和脑内压力变化是造成颌面部损伤合并颅脑损伤的重要生物力学因素

Study on Maxillofacial Impact Injury Associated with Brain Injury

OBJECTIVE: The purpose was to study the mechanism and the characteristics of brain damage associated with maxillofacial injury under the impacting load of middle face. METHODS: Eighteen rabbits were subjected to impacting on left middle face with pneumatic impact device, which were horizontally located on the ground. The impact velocities respectively were 4.77 m/s +/- 0.53 m/s (group A), 9.16 m/s +/- 0.65 m/s (group B) and 13.95 m/s +/- 0.67 m/s (group C). The acceleration of head and stress of encephalic was monitored during the impact period. The pathological characteristics of correlative tissues were examined in detail 6 hours after impacting. The contents of LPO, SOD and NO in blood and water in brain were measured at the same time. RESULTS: The contents of LPO and SOD in blood significantly increased along with the increasing of impact velocity (P < 0.05). The same pattern was observed in the changing of water content of brain (P < 0.05). But the contents of NO in blood reduced when the impact velocity increased (P < 0.05). The animals of group A showed single fracture of middle face bone, while Group B showed multiple fractures of middle face bone. Group C represented severe maxillofacial injury associated with brain damage. The pathological damage of brain became more serious along with the increase of impact velocity. The peak value of head acceleration and encephalic stress of group C were higher than that of group A and group B (P < 0.05). CONCLUSION: The responses of head acceleration and encephalic stress resulting from middle face impacting might play a key role in brain injury associated with maxillofacial injury.