Applications Of Three-dimensional Ct Angiograph In The Operation Of Posterior Atlas Fixation

Objective:To observe normal three-dimensional CTA images of the upper cervical spine. The anatomy of atlantal posterior arch and the accompanying VA’s journey were studied, to provide the basis of micro vascular anatomy for clinical treatment.Methods:Four hundred cases without pathological lesions of atlantoaxial joint were selected from the3D data of head-neck CTA examination. All the3D images were formed with volume rendering (VR) together with the techniques of separating, fusing, opacifying and false-coloring (SFOF). On the3D images, the courses and variations of VA were observed, and the posterior screw-related date of the atlantal posterior arch were measured.Results:All the3DCTA images are of high quality and up to our requirements. The courses of VA accompanied with the atlas were curved. There were385cases with typical itinerary, accounting for96.25%. Variations were found in15cases, including3cases of bilateral variation, a total of18sides. There were11sides of persistent first intersegmental artery (PIA),6sides of fenestrated VA (FA),1side of abnormal posterior inferior cerebellar artery (PICA) respectively.48cases of posterior ponticulus were found, accounting for12%.10cases were bilateral, a total of58sides. The bottom of the vertebral artery’s groove was the weakest part of the posterior arch, its left and right height was (4.45±0.70) mm and (4.64±0.72) mm, while its left and right width was (8.61±1.03) mm and (8.82±1.00) mm.Conclusion:The shape of the atlantal posterior arch and the vicinal VA are polytropic. Therefore, preoperative radiological studies should be performed to identify any anatomical variations. Using preoperative3DCT angiography, we can precisely identify those important informations and improve the safety of operation.