The study and design of atlantoaxial lateral mass intervertebral fusion cage for BI-AAD patients

ZHAO Xinghua; XIA Zhiyuan; JIAN Fengzeng; CHEN Zan

Abstract：Objective The geometry of the lateral joint of BI-AAD patients was measured and the loosening tool and the corresponding intervertebral fusion cage were designed.Methods A total of 28 cases of BI-AAD patients were collected from our hospital and cooperative hospital between November 2015 and April 2016 as experimental group,with 25 cases of normal people as control group.The clinical data and the cranio cervical thin CT scan data were collected,and the diameter length of lateral atlantoaxial joint in ooronal section and vertical section,atlantodental interval,sagittal joint inclination,Chamberlain line,and the craniocervical tilt were measured with the RadiAnt DICOM Viewer (32-bit) software.An intervertebral fusion cage for BI-AAD patients was designed and analyzed.Results The data showed that there was no significant difference between the left and right joints in the two groups (P ＞0.05).The diameter length of atlantoaxial lateral mass in coronal section and vertical section and atlantodental interval of BI-AAD patients were significantly less than those of control group (P ＜0.001).The sagittal joint inclination,and the craniocervical tilt,atlantodental interval of BI-AAD patients were significantly bigger than those of the control group (P ＜0.001).Therefore,we designed the atlantoaxial lateral joints fusion cage for BI-AAD patients according to the measurement data.Conclusion There are different degrees of deformity in the lateral atlantoaxial joint of BI-AAD patients.Based on the morphology of lateral joint deformity,an atlantoaxial lateral mass intervertebral fusion cage,joint facet scraper and joint loosening tool are designed.