[Analysis of a three-dimensional finite element model of atlas and axis complex fracture].

Objective: To explored the clinical application of the three-dimensional finite element model of atlantoaxial complex fracture. Methods: A three-dimensional finite element model of cervical spine (FEM/intact) was established by software of Abaqus6.12.On the basis of this model, a three-dimensional finite element model of four types of atlantoaxial complex fracture was established: C(1) fracture (Jefferson)+ C(2) fracture (type Ⅱfracture), Jefferson+ C(2) fracture(type Ⅲfracture), Jefferson+ C(2) fracture(Hangman), Jefferson+ stable C(2) fracture (FEM/fracture). The range of motion under flexion, extension, lateral bending and axial rotation were measured and compared with the model of cervical spine. Results: The three-dimensional finite element model of four types of atlantoaxial complex fracture had the same similarity and profile.The range of motion (ROM) of different segments had different changes.Compared with those in the normal model, the ROM of C(0/1) and C(1/2) in C(1) combined Ⅱ odontoid fracture model in flexion/extension, lateral bending and rotation increased by 57.45%, 29.34%, 48.09% and 95.49%, 88.52%, 36.71%, respectively.The ROM of C(0/1) and C(1/2) in C(1) combined Ⅲodontoid fracture model in flexion/extension, lateral bending and rotation increased by 47.01%, 27.30%, 45.31% and 90.38%, 27.30%, 30.0%.The ROM of C(0/1) and C(1/2) in C(1) combined Hangman fracture model in flexion/extension, lateral bending and rotation increased by 32.68%, 79.34%, 77.62% and 60.53%, 81.20%, 21.48%, respectively.The ROM of C(0/1) and C(1/2) in C(1) combined axis fracture model in flexion/extension, lateral bending and rotation increased by 15.00%, 29.30%, 8.47% and 37.87%, 75.57%, 8.30%, respectively. Conclusions: The three-dimensional finite element model can be used to simulate the biomechanics of atlantoaxial complex fracture.The ROM of atlantoaxial complex fracture is larger than nomal model, which indicates that surgical treatment should be performed.目的： 探索寰枢椎复合骨折三维有限元模型的临床应用。 方法： 在正常全颈椎有限元模型的基础上，应用有限元ABAQUS 6.12软件，建立4种不同类型的寰枢椎复合骨折的全颈椎有限元模型：C(1)(Jefferson)骨折＋C(2)(Ⅱ型骨折)、C(1)(Jefferson)骨折＋C(2)(Ⅲ型骨折)、C(1)(Jefferson)骨折＋C(2)(Hangman)骨折、C(1)(Jefferson)骨折＋C(2)(稳定性骨折)模型(FEM/fracture)(FEM/fracture)，测量颈椎在前屈、后伸、侧屈、旋转等工况下活动度(ROM)，并与正常全颈椎有限元模型测量结果进行比较。 结果： 建立的寰枢椎复合骨折有限元模型几何相似性好，各个工况下活动度在不同节段有不同改变。C(1)骨折＋Ⅱ型齿状突骨折其C(0/1)、C(1/2)相对于正常模型前屈＋后伸、侧屈、旋转活动度明显增加，分别增加57.45%、29.34%、48.09%及95.49%、88.52%、36.71%；C(1)骨折＋Ⅲ型齿状突骨折其C(0/1)、C(1/2)节段分别增加47.01%、27.30%、45.31%及90.38%、27.30%、30.02%；C(1)骨折＋Hangman骨折其C(0/1)及C(1/2)分别增加32.68%、79.34%、77.62%及60.53%、81.20%、21.48%；C(1)骨折＋稳定性枢椎骨折其C(0/1)及C(1/2)分别增加15.00%、29.30%、8.47%及37.87%、75.57%、8.30%。 结论： 不同类型寰枢椎复合骨折三维有限元模型能较好模拟临床实际情况，可对寰枢椎复合骨折的患者进行生物力学研究，寰枢椎复合骨折时比无损伤状态时有更大活动度，提示应进行手术处理。.