| Objective:A three-dimensional(3D)printing guide plate for the anterior cervical pedicle screw(ATPS)insertion was designed and manufactured,and the accuracy of the guide plate was analyzed.On this basis,the feasibility and clinical value of the 3D printing anterior bilateral pedicle screw fixation in cervical tuberculosis(CTB)single-segment fusion and fixation were also analyzed and evaluated.Methods:Four Sawbones cervical spine models(C1-C7)were scanned by computed tomography(CT),and a safe anterior pedicle screw insertion channel was designed by Mimics 19.0 software.Twenty anterior pedicle screws were inserted into the cervical vertebral model(C3-C7)with the assistance of 3D printing guide plate.The cervical spine model after the screw insertion was scanned again by the CT,and the values of the screw deviating from the midline in the transverse and sagittal plane of the pedicle were measured.The safety of the screw insertion was evaluated according to the absolute and relative values of the screws deviating from the pedicles.Secondly,a case of the C5-6 single-segment CTB fusion was collected and treated by the spinal surgery of Jiangxi Provincial People's Hospital Affiliated to Nanchang University.Furthermore,the finite element comparative analysis(FECA)of artificial vertebral body group with bilateral pedicle screws fixation and group of conventional titanium mesh and plate fixation was performed after operation.In this process,the artificial vertebral body was implanted into a single-segment vertebral body model and the titanium mesh and plate were implanted into a long-segment interbody model at the same time.Stress cloud diagram under the static load,forward flexion,backward extension,left torsion,right torsion,left bending and right bending were collected respectively,and the stress distribution and the possibility of adjacent vertebral degeneration were compared and analyzed.Results:There was no significant difference in transverse internal and external displacement of anterior pedicle screws(P=0.688),and there was no significant difference in sagittal upward and downward displacement(P=0.967).According to absolute value of screw deviation from the pedicle,the number of screws in safe position was 19/20(95%);according to relative value of screw deviation from pedicle,the number of dangerous screws was 0/20.Secondly,based on the safety and accuracy of the ATPS insertion,3D printing anterior bilateral pedicle screw fixation of the artificial vertebral body can be effectively applied for single-segment fusion of CTB,and the efficacy and prognosis were ideal.Postoperative follow-up showed that the artificial vertebral body was fixed in place,and there were no signs of loosening in the pedicle screws,which obtained the bone fusion and the tuberculosis was completely cured.Besides,the single-segment model of artificial vertebral body implanted between C5-6 vertebral body and the long-segment model of conventional titanium mesh and plate implanted between C4-7 vertebral body were successfully constructed after operation,and the FECA was also performed.The results show that the fixed stress of artificial vertebral body group was more evenly dispersed under the conditions of static load,forward flexion,backward extension,left torsion,right torsion,left bending and right bending,while the fixed stress of titanium mesh and plate group was generally concentrated.Conclusions:The insertion of ATPS assisted by the 3D printing guide plate is safe and effective,and the artificial vertebral body fixed with anterior pedicle screws can be effectively applied in the CTB single-segment fusion and fixation,which can achieve the ultra-short segment fixation.By comparing the artificial vertebral body group with the titanium mesh and plate group,it can be known that the artificial vertebral body fixed with anterior pedicle screws can effectively delay the degeneration of adjacent vertebral bodies and intervertebral discs,and maximize the retention of cervical motion segments and functions. |
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