| Objective:In order to establish an atlas, measure the separate atlas specimens anatomical to find the anatomical data, to help choose the right pedicle screw. Support for clinical atlas into the nail, and measuring the angle of the screw channel with a specific plane, screw placementsupported.Methods:Guilin Medical College Department of Anatomy, provided the30specimens of dried bone specimens (excluding damaged and deformed specimens),regardless of age, sex, height, and other effects of30specimens were unarmed atlas screw Road pedicle screw placement. Take the midpoint of the inside and outside edge of the lateral mass of atlas posterior arch projection from the vertebral artery base groove at the thinnest at2mm pedicle screws along the sagittal plane by the side of the block point to the entrance angle a, screw axis in the sagittal plane and the plane of Atlas formed by the side of the vertical angle β. Using the appropriate length of the screw is placed according to design good screw channel. Completed placed screws and then remove it and use the protractor to measure the horizontal angle alpha; screw and atlas lateral plane angles, namely the pedicle angleβ; then use vernier caliper to measure the sulcus of vertebral artery of posterior arch at the bottom of the thinnest height (h), and the maximum width of the measurement of bow out (W) Cl screw entrance point; the width of Wl, the distance Dl nodules and the entry point. The total length of screw channel (AB); between atlas lateral mass underneath the dorsal edge and the outer edge of the length of D2. The measured data using SPSS software processing statistics. Radiography before the measurement with a digital camera and Photoshop software protractor measurements, length domestic vernier caliper, each specimen repeated measurements be accurate.Results:(1) the bottom of the atlas vertebral artery groove bow at the thinnest width greater than height (w> h), there are differences (P<0.05) by t test.(2) The vertical distance between the atlas into nail point after nodules was20.9±3.1mm.(3) The atlas screw bone screw channel in total length (i.e. the starting point along axis A to reach the distance) of the vertebral i. e. the AB total length of25.2±2.9mm. (4) the distance between the inside and outside edge at the bottom of the side block dorsal D2atlas was10.9±1.1mm.(5) The atlas pedicle screws horizontal angle (a) of10.8°±3.9°; vertical angle (β) measurement was4.2°±0.8°Conclusion:atlas pedicle screw fixation anatomically feasible, take atlas lateral mass below the midpoint of the inside and outside edge of the projection from the posterior arch bow at the thinnest vertical distance of2mm at the bottom of the vertebral artery grooveplaced in the entrance point of the screw; screw placement to take lateral angle10.8°±3.9°， vertical angle of4.2°±0.8°; atlas screws choose a diameter of3.5mm, the posterior arch of the atlas height is decided atlas screw keyfactors, the length of21~30mm screws, into the nail depth is not more than30mm, it is feasible, safe and reliable. |
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