Experimental study of individualized 3D printing navigation template in the treatment of upper cervical pedicle screw placement

Abstract

Objective To evaluate the accuracy and safety of individualized 3D printing-oriented template in the treatment of upper cervical pedicle screw placement. Methods The preoperative data of CT scan of 13 patients with cervical diseases in the CT Center of the Second Affiliated Hospital of Bengbu Medical College from October 2013 to September 2015 were analyzed by Mimics 15.0, Geomagic Studio 2013 and NX 8.5, and the use of 3D printing technology to print out the cervical and other proportional solid model, the upper cervical pedicle screw placement guide template. Two copies of each cervical spine model were divided into two groups: the experimental group was inserted into the atlantoaxial pedicle screw with the guide template. The control group was implanted with atlantoaxial pedicle screw by using imaging X-ray method. Two groups of upper cervical pedicle screw were placed by the same chief physician of spinal surgery. To evaluate the accuracy of screw placement in the sagittal plane and the cross-section of the pedicle by postoperative CT data, and whether the need for renovation, the accuracy of the fixation of the upper cervical pedicle screw was divided into 3 classes, in which class Ⅰ and Ⅱ type screws were acceptable nail, Ⅲ type screws were unacceptable nail. Results The experimental group: 19 blocks of upper cervical 3D printing screw guide templates were designed and printed, 37 pedicle screws of atlas and axis were inserted, including classⅠ 33 screws (86.49%), classⅡ 2 screws (8.11%) and classⅢ 2 screws (5.40%). The mean time of implanting a screw into upper cervical pedicle was 5.37±1.26 minutes. The average number of X-ray machine fluoroscopy of placing a screw was (5.48±1.19) times and the length of the screw was (28.38 ± 2.98) mm. The control group were implanted with the method of C-arm X ray fluoroscopy on a total of 37 upper cervical pedicle screws, of which class Ⅰ 23 screws (62.16%), Ⅱ 3 screws (8.11%), Ⅲ 11 screws (29.73%). The mean time of implanting a screw into upper cervical pedicle was 11.48±2.32 minutes. The average number of X-ray machine fluoroscopy of place a screw was (17.85±2.96) times and the length of the screw was (28.65±2.83) mm. The success rates of the screws in the experimental group and the control group were 94.60% (35/37) and 70.27% (25/37), respectively, the difference was statistically significant (Z=-5.790, P 0.05). The number of fluoroscopy in the experimental group was significantly lower than that in the control group, and the difference was statistically significant (t=-14.078, -23.586, all P values<0.01). Conclusions The personalized guide template assisted the superior cervical fixation significantly improved the safety and accuracy of the nail fixation, especially for the severe deformity of the upper cervical vertebral body. 3D print individualized cervical pedicle screw fixation nail guide plate shows the principle of individualized nailing. It can be clinically promoted with high success rate, safety, effectiveness and feasibility. Key words: Cervical vertebrae; Therapy, computer-assisted; Pedicle screws; Navigation template