Geometric Model Of Reduction In Basilar Invagination With Atlantoaxial Dislocation And Its Clinical Application

[Objective]To establish a geometric model of the Atlantoaxial dislocation and Basilar invagination reduction,to estimate the theoretical reduction distance and the theoretical reduction angle of the atlantoaxial in different cases before operation,and use it for intraoperative quantitative reduction.[Methods]A retrospective analysis of 35 patients with Atlantoaxial dislocation and Basilar invagination admitted in the Department of Neurosurgery,First Affiliated Hospital of Chongqing Medical University.All patients measured the relevant data according to the geometric model before the operation,and based on it,the fusion cage of the corresponding height was selected during the operation and placed in the C1/2 facet joint,quantitative reduction was performed.Compare the difference between the theoretical reset value and the actual reset value to verify the reliability of the geometric model.[Results]The theoretical vertical reduction distance(TVRDA)of all patients was 5.79±2.96 mm,and the actual vertical reduction distance(AVRDA)was7.43±2.96 mm.There was no statistical difference(t=-1.96,p=0.069> 0.05);the theoretical reduction angle(TRA)was 10.80±2.24°,the actual reduction angle(ARA)was 10.64±7.00°,there was no statistical difference(t=0.085,p=0.933>0.05).After 6 months of continuous follow-up,all patients achieved satisfactory fusion,and their symptoms were significantly relieved compared with preoperatively.The JOA score increased from 10.2±2.1 points preoperatively to 13.5±2.3 points.There were no complications such as rupture,displacement of the internal fixation system,and infection of the operation area.[Conclusion]This geometric model can estimate the vertical reduction distance and the reduction angle of the axial before operation,and provide a reference for the height of the fusion cage,the angle of the cantilever pressure rod and the degree of reduction during the operation,so as to avoid under-reduction or over reduction.Make the operation more reasonable and accurate.