Biomechanical Of Lateral Atlantoaxial Articulation In Craniovertebral Junction Malformation:afinite Element Analysis And Research On Operation Strategy

Background and objectives: CVJM(Craniovertebral Junction Malformation) is diseased from the skull base to disc area between axis C2(Cervical 2) and third cervical vertebra C3(Cervical 3),such as atlantoaxial dislocation and skull base depression etc, and it is harmful to nerve function so that the patient has symptoms of fatigue and walking instability and so on. The operation usually including atlantoaxial internal fixation and posterior occipital cervical posterior internal fixation is a effective method to treat deformity, but the patients with craniovertebral junction malformation has usually abnormal situation such as vertebral artery exist widely abnormal anatomic deformity. At this time if we do the surgical operation of pedicle screw fixation, We will damage the spinal cord and vertebral artery easily. The general construct of internal fixation instruments are based on the axial pedicle screw. When deformity of axial pedicle bone is insufficient for pedicle screw, the fixation can’t satisfy the required treatment of CVJM. At the sa me time, the axial lamina in patients on the height and thickness is superior to condition of normal bone for placement. Therefore, based on medical data of CVJM, we established a finite element model and get the data withthe atlantoaxial joint surface stress distribution. All of this will provide a new way for us to how to choice operation scheme and design the internal fixation device in the future.Methods: CT scan images of the were obtained. The Analytical model was constructed by advanced three-dimension modeling and finite element softwares. A comparison of range of motion difference between the deformity model and normal model, referring to the experience of clinical observation, was used to verify the validity of the model. applying respectively the same loads and boundary conditions on Finite element model. The effectiveness was verified by contrastive analysis of the variation in lateral atlantoaxial joint stresses;according to the results of anatomical measurement and finite element analysis,38 cases of patients with CVJM operate on the help of the digital navigation.Results: the finite element model with high geometric accuracy and Reliable parameter had built.Compared to the results of cadaver test and finite element model based in normal cranio-vertebral junction, the segment mobility coincides with the actual clinical performance in patients. The stress distribution the lateral junction between atlas and axis of can be reasonably explained the deformation of lateral atlantoaxial joint structure and its important role in remaining stable between atlantoaxial vertebrae under different physiological conditions,Conclusions: The structure of lateral atlantoaxial joint changes in patients of craniovertebral Junction malformation, the biomechanical stability for preoperative diagnosis and intraoperative treatment operation has a certain value. In the clinical practice,4 kinds of classification methods are proposed, which provides a new, safe and reliable method for doctors.