Design Of Individualized Pedicle Guide Plate With 3D Printing And The Accuracy Evaluation Of Simulation Placement In Vitro

Objective: Pedicle screw placement technique is a skill that spine surgeons must master,for experienced spine surgeons,the incidence of screw placement is still greater than 10%,and there is a long learning curve in the technique by hand placement.Pedicle screw misplacement can cause nerve,viscera,blood vessel and other complications,although the incidence is low,but the consequences are serious,In addition,the screw position deviation to weaken the screw holding force,may cause some long-term complications.In this study,to design an individual pedicle guide plate with 3D printing and to simulate the placement of screw in vitro,this design plate will significantly reduced the difficulty of place screws and improve the placement accuracy.And to further explore the feasibility of vertebral pedicle screw placement.For the next step to provide practical experience in clinical application.Methods: Traditional pedicle screw placement depends on the surgeon’s experience and imaging data,various factors affect the subjective judgment of the surgeon,so place the screw variable is relatively large,it’s difficult to place screws and the misplacement rate is high.This study by 3D printing technology,preoperative planning and design of individual pedicle screw guide,no longer rely on the subjective judgment of the surgeon,but owing to guide plate objectively,this makes it easy and fast to place the screw process,theoretical placement accuracy will reach 100%.This study is to explore the assisted screw method,the specific process is divided into the following two parts.1 Lumbar spine CT scan data of 1 patient with degenerative lumbar spine(lumbar spinal stenosis)were selected from Hebei General Hospital in April2016.Three-dimensional reconstruction of the patient’s lumbar 1,3 and 5vertebral body.According to the patient’s lumbar CT data to do pre-experiment.Then according to the principle of screw placement,the screw position and orientation of the screw were designed,and the “best” pedicle guide plate model was designed.2 Lumbar spine CT scan data of 10 patients with degenerative lumbar spine(lumbar spinal stenosis)were selected from May 2016 to July 2016 in Hebei General Hospital.Three-dimensional reconstruction of each patient’s lumbar 1,3 and 5 vertebral body.According to the pre-experiment design“best” guide model,planning the screw position and orientation of the screw,each patient’s lumbar spine and its individualized pedicle guide plate were made,and then cut open to verify the placement of screw after simulation place screws in vitro model.Results:1 Pre-experimental design of the pedicle guide plate looks simple,beautiful,and the pedicle guide plate contact is good,no sliding or deformation and other adverse events,confirmed it’s easy to place screw operation;2 In the experiment,thirty pedicle guide plates and sixty screws were used in this experiment.Simulating the process of setting the screws well and the pedicle guide plate contact is good,no case of pedicle screw perforation pedicle cortex,screw position is accurate and reliable,the experimental result is good;3 The difference of the angle of the left pedicle screw in the transverse section of the test statistic Z value is-1.604 and the right is-1.381,left P =0.109> 0.05,right P = 0.167> 0.05.The difference of the angle of the left pedicle screw in the sagittal section of the test statistic Z value is-0.568 and the right is-0.510,left P = 0.570> 0.05,right P = 0.610> 0.05.According to the inspection level α=0.05.There was no significant difference in the transverse section angle and sagittal section angle between the right and left pedicle screw.Conclusions:1 This experiment design of the pedicle guide plate is simple and beautiful,the pedicle guide plate contact is good,making it easy to place the screw,and the screws are in good position;2 There was no statistically significant difference in the direction of advancement after placement of the screws.It is confirmed that the placement of individual pedicle guide plate in 3D printing is feasibility initial,but further study is needed in Clinical.