| Objective: Pedicle screw internal fixation technique has been widely used in spinal surgery .The depth of the screw is generally up to 80% of the sagittal diameter of the vertebral body in the patients with good bone density, but the postoperative complications of internal fixation is still more common in osteoporosis patients.Recently, it has been reported that the CBT technique can significantly improve the stability of the screw fixation in osteoporotic patients. However,because of the nerve and blood vessels adjacent to the vertebral pedicle and lumbar spine, the accuracy of the CBT technique must be higher. The purpose of this study is to rebuild the lumbar spine CT image data by digital technology before operation,virtual inserting CBT screws, measure screw data, and provide individual guidance for the placement of CBT screw, in order to improve the accuracy of the CBT technique.Methods: The data of the lumbar CT scan images collected from 30 patients admitted to the Tumor Hospital of Yunnan Province from 2014 to 2016.The DICOM format of the original data are imported into Mimics 17.0 for image processing and 3D modeling Reconstruction, measurement of vertebral canal sagittal diameter,vertebral sagittal diameter, pedicle width, height, centrum height of the vertebral body, virtual double cortical pedicle screw length, screw diameter, crossed corners of the cruciform, sagittal Angle. The measured parameters were analyzed by SPSS 20.0 and Graphpad Prism5 software. The results of each individual measurement were compared with the sex of the patients, and discussing the relationship between them.The sex was divided into two groups, an independent sample t test was used to analyze the sex group. The parameters of the left and right vertebrae were tested by using the independent sample t test. It is with α = 0.05 as the test standard. For each individual parameters of L1-L5, we use the variance analysis method and LSD comparison to check whether it changes with the segment and observe the change trend of each individual parameters from L1 to L5.Results: The SCSD,PH,PW and CSD from L1 to L3 vertebrae were significantly different between men and women (P <0.05). The mean height of the PH, PW and CSD of the vertebral body were male> female, while the mean value of the SCSD from L1 to L3 vertebrae was female> male.The length of the CBT screw were male>female. There is a significant difference in the average length of CBT screw between male and female (P <0.05). The length of virtual CBT screws from L1-L5 were 36.75 ± 3.18mm,38.19 ± 3.20mm,39.36 ± 3.32mm,39.79 ± 3.49mm and 38.32 ±3.88mm respectively. From L1-L4, the length of the virtual cruise line gradually increased, while L4-L5 showed a significant downward trend. After comparison showed, in addition to between L2 and L5, L3 and L4 the outer no significant differences,pairwise comparisons were significant differences (P<0.05).The diameter of virtual CBT screw from L1-L5 was 6.21 ± 1.10mm,6.22 ± 1.10mm,6.91 ± 1.20mm,7.35 ± 1.30mm and 8.42 ± 1.40mm respectively. From L2-L4, the diameter of the virtual screw is gradually increasing. There was no significant difference between L1 and L2, and there was significant difference between the others (P<0.05). The TSA of the virtual CBT screw from L1-L5 were 8.50 ± 2.40 °,8.60 ± 2.30 °, 9.10 ± 2.40 °, 9.20 ± 2.30 0 and 8.80 ± 2.10 0. After comparison showed ,there was no significant difference between the these groups (P> 0.05). The sagittal screw angle (SSA) of the virtual CBT screw from L1 -L5 was 26.20 ± 4.40°,25.50 ± 4.50 °,26.10 ± 4.90 °, 26.00 ± 4.50° and 25.80 ± 4.70°. After comparison showed,there was no significant difference between these groups (P> 0.05). There is no regular trend between TSA or SSA and lumbar segment.Conclusions: The L1-L3 pedicle height(PH), width(PW) and vertebral sagittal diameter in male patients is generally bigger than thats of female patients, and the L1-L3 vertebral body sagittal diameter in male patients is generally smaller than female patients. The mimics can simulate the stapling and measure the related surgical parameters before operation, which can provide a high reference value for clinical operation..Simulating the lumbar pedicle screw placement by using software found that the left and right sides of the pedicle screw length and diameter have no significant difference.The pedicle screw length of male patients is significantly longer than thats of female patients.There was no significant difference between men and women in screw diameter. The length of the virtual screw length is increasing from L1 to L4, and the diameter of the virtual screw increases gradually from L2 to L5. |
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