Anterior Compression Index For Evaluating Atlantoaxial Dislocation And Restoration

[Objective]Deduction and application of anterior compression index for evaluating atlantoaxial dislocation and restoration.[Method]28 cases of the control group persons and 28 cases of atlantoaxial dislocation treated with posterior restoration and screw-rod internal fixation technique before and after surgery were recruited in this study and their data was retrospectively analyzed.All of the people underwent sagittal computerized tomography scan films.The anterior compression index was measured in all cases.[Results]The mean value of anterior compression index of the control group persons was 87.86±24.98 mm2.The mean value of anterior compression index of the preoperative patients was 230.44±97.60 mm2,and the mean value of the postoperative patients was 106.27±73.53 mm2.It showed that there was significant difference between the preoperative patients and the control group persons(t=-7.50,P<0.0001).There was no significant difference between the postoperative patients and the control group persons(t=-1.26,P=0.2171).Anterior compression index of the postoperative patients were significantly lower than those of the preoperative patients(t=10.35,P<0.0001).[Conclusion]Anterior compression index can be an excellent measurement tool for the assessment of relationship of atlas and axis in atlantoaxial dislocation patients before and after posterior restoration operation.