[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).


CONCLUSIONS
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.
Bo
B
B
Department of Oral and Maxillofacial Surgery, Stomatological College, Fourth Military Medical University.
Zhou
S
S
Zhang
M
M
He
L
L
D000818:Animals; D001696:Biomechanical Phenomena; D001930:Brain Injuries / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D007427:Intracranial Pressure; D008297:Male; D008446:Maxillofacial Injuries / Q000150:complications*; D011817:Rabbits