Accuracy Study Of Individualized 3D Printing Navigation Template For Pedicle Screw Fixation In Upper Cervical Spine

Objective:1.Evaluate the accuracy of individualized 3D guides for assisting atlantoaxial pedicle placement by comparing the pre-designed virtual screws of the atlantoaxial vertebrae and the Individualized 3D guide plate assisted placement of pedicle screws2.Dissect the pedicle of the Corpse specimen,see if the pedicle is broken or not,and evaluate the success rate of the individualized guide plate to assist the upper cervical pedicle screw placement.Methods:1Using a 64-slice CT scan of ten fresh cervical cervical adult cadaver specimens to obtain DICOM format data,import it into the reverse engineering software mimics 17.0,Reconstruction of high precision cervical vertebrae models。Designing the virtual screws path according to the principle of method of intraoperative implanting pedicle screw,and fine tune the path of virtual screw,Measure and record the direction of the virtual screw.The temporal cortical data of the atlas and the posterior axis were extracted,and the individualized guide plates were designed in reverse.We print out the guide and pair with human cervical specimens,andplace the atlantoaxial pedicle screw under the navigation of the guide.Using a 64-slice CT scan of ten fresh cervical cervical adult cadaver specimens again,import it into the reverse engineering software mimics 17.0.We measure and record the direction of the actual screws.The virtual screws data is compared with the actual screws path to evaluate the accuracy of the individualized 3D guide plate to assist the upper cervical spine.2.Remove the soft tissue around the pedicle,see if the pedicle screw breaks through the cortex,use the oscillating saw to open the pedicle,and demonstrate the feasibility of individualized guide plate assisted upper cervical pedicle screw implantation.Results:1In this experiment,10 specimens were used,20 3D guide plates,40 screws,20 C1 pedicle screws and 20 C2 pedicle screws,20 left pedicle screws,and right pedicle screw.20 pieces.The simulated Implanting process was smoothly,and the guide plate was closely attached to the posterior arch surface of the atlas and the posterior surface of the atlas vertebral lamina.The guide plate did not move laterally.Weimport actual nail and virtual nail data into SPSS.Verify the normality of the data using Q-Q plots in SPSS software.The date of the virtual screws and the actual screws of the atlas and the atlas are subject to a normal distribution.We select the paired sample t test to calculate the mean and standard deviation of the two sets of data.The specific data are shown in the figure,according to the test level α=0.05(two sides),p>0.05,so it can not be considered between the virtual nail path and the actual nail track.The difference was statistically significant.2.The soft tissue around the pedicle was removed to see the integrity of the pedicle.The vertebral body was dissected with a oscillating saw to confirm that the nail was located in the pedicle and the distance between the edge of the nail and the cortical bone of the pedicle was measured.A total of 40 pedicle screws were placed,and 40 screws did not break through the pedicle cortex.After the dissection,it was confirmed that the nails were located in the pedicle,and the success rate of nail placement was 100%.