The Biomechanical Analysis Of Fracture Of The Skull Base Caused By Traffic Accidents

Objective: To analyse the mechanism of the fracture of the skull base causedby external shocks in the simulated traffic accidents, and clarify the relationshipbetween the strength and position of force and the fracture of the skull base.Method: To establish the three-dimensional finite element model of the skull basecontaining the lower jaw,and analyse the changes of the model loading differentstrength of force by using the workbench of the anasys13.0sofeware. Firstly, thebilateral occipital condyle will be restrained, and the forehead will be loading forcehorizontally backwards, respectively for100N、200N、300N、400N. Then, the occipitalcondyle will be loading force vertically, respectively for400N、800N、1200N, on thecondition of top of the skull restrained. Lastly, by restraining the bilateral occipitalcondyle, the mandible will be loading force horizontally backwards, respectively for0°、40°、50°、60°at the successive condition of200N、300N、400N. The workbench willcomplete the analysis solution, and get the commensurate displacement and equivalentstress nephogram. Result: when the loading force of the forehead horizontallybackwards reached300N and400N, the anterior cranial fossa occurred a significantdisplacement with the shape variables about1mm, which will lead to the fracture of it.At the same time, the posterior cranial fossa occurred a stress concentration area, andthe equivalent stress will overrun the limit of the yield with the strength of400N, whilethe stress contour of the middle cranial fossa could not reach the yield limit. In theprocess of the occipital condyle loading force vertically, the posterior cranial fossaoccurred a significant stress concentration area, which did not reach the yield limit ofthe skull base, and it would not lead to the fracture of the posterior cranial fossa. In thecourse of the mandible loading force horizontally backwards, a significant stressconcentration area and displacement can be observed at the middle cranial fossa, and thefracture of it will happen with the strength of300N and400N in spite of different loading angle. Moreover, with the increasing loading force gradually. the stressconcentration is becoming evident in the posterior cranial fossa, and it will exceed theultimate load of the skull base,which can cause the fracture at the strength of400N.Conclusion: In the process of traffic accidents, the impact of the forehead and themandible suffered can be conductive to the skull base,which can lead to the fracture ofthe corresponding skull base area. When the forehead is subjected to the impact, thefracture of the forehead will happen, and the fracture line would extend to the anteriorcranial fossa. The mechanism of the fracture of the posterior cranial fossa tend to thestress concentration. When the mandible is subjected to the impact at the fixed angle,the stress transmit to the skull base along the mandibular ramus, which will lead to thefracture of the middle cranial fossa, and the the stress concentration of the posteriorcranial fossa. The fracture of the posterior cranial fossa will happen at the strength of400N.