Application Research Of A Novel Laser Positioning And Navigation System For Pedicle Screw Insertion

Objective Pedicle screw insertion is a commonly used spinal internal fixation technology.However,because of the special morphology of pedicle,and the abundant blood vessels and nerves beside the vertebral body,it is difficult to locate the position in the process of puncture and placement of pedicle screw.Puncture failure often leads to disastrous consequences.Accurate determination of "positioning","orientation" and "depth" in the process of pedicle puncture and nail placement is a hot spot in the research of surgical navigation in the Department of orthopedics.The laser positioning and navigation system based on C arm is easy to operate.The operation path is direct and the positioning accuracy is <1mm.Its linear navigation principle is different from the commonly used computer aided surgery(CAS,GPS like location principle).The aim of this study is to evaluate the feasibility,safety and accuracy of laser guided placement of pedicle screws under linear navigation.Methods For the first part of the experiment,to establish human spine pedicle puncture point model,C arm machine along the spine axis at-30 DEG ~30 DEG to 5 DEG intervals of rotation and perspective of vertebral pedicle image positioning was verified by laser puncture point position.In the second part,through the normal human spinal CT 3D reconstruction data,computer simulation,to determine the best sites of the best angle and the best depth of puncture,puncture and pedicle screw measurement in the process of perforation of medial and lateral cortical angle threshold;3D print vertebral body,with the disposal of steel ball in the best puncture point,analysis of the 3D printing vertebral body imaging in C arm machine,verify the feasibility of linear navigation assisted pedicle screw placement and puncture.In the third part,5 cadaver specimens,with experimental group and control group respectively corresponding to the same vertebral pedicle specimens,preoperative CT scan,and plan operation path;the experimental group underwent laser navigation assisted percutaneous pedicle screw fixation,the control group using open pedicle screws unarmed operation,record of vertebral body pedicle and pedicle screw positioning time,operation time.Using X-ray and CT scanning after operation,according to the Gertzbein and Robbins evaluation system to judge the success rate of pedicle screws;the actual postoperative pedicle screw insertion point,the actual screw path and the optimal entry point,the best placement path for comparison in CT image,on the part of the CT scanning metal artifact large incision vertebral pedicle screw through the cortex,direct judgment,evaluation of placement accuracy.Results(1)The imaging of vertebral pedicle and its puncture point in the C arm machine changes with the change of vertebral body angle.The angle of perspective of C arm machine can be adjusted to the axis of pedicle,which can be combined with laser linear navigation.(2)Pedicle axis perspective,the best puncture point(steel ball sites)in the Pedicle film center,the C arm X-ray and computer simulation calculations to adjust the angle after the reconstruction of the Pedicle deviation angle fit,Pedicle axis perspective position for laser linear optimal puncture guide navigation,the navigation device according to the deflection angle Pedicle estimates from the deflection angle,adjustment from vertebral standard anteroposterior position to Pedicle axial is simple,reasonable and feasible.(3)The Gertzbein and Robbins system was used to evaluate the experimental group and the control group placement accuracy,input SPSS(19.0),the experimental group placement success rate was 94.29%(33/35),the control group was nailing achievement rate was 91.42%(32/35),chi square test was performed,the P value of >0.05,no statistical difference;the needle point deviation from the value of the experimental group(control group),1.08±0.76mm(2.61±0.89mm),had statistical significance(mean of difference = 1.53 mm,95%CI = 1.34-1.72,P<0.05);the needle direction deviation from the value of the experimental group(control group),2.41±1.18°(4.52±0.99°),had statistical significance(mean of difference = 2.11,95%CI = 1.59-2.52,P<0.05),the experimental group placement accuracy due to the control group;the vertebral body and the vertebral arch root positioning time the experimental group average was 294.9± 50.93 s,the control group average was 433.3±60.78 s,the operation time of experimental group was 506.2±63.7s,the control group was 633.7±114.9s,P values were less than 0.05,both had statistical difference,navigation Nailing can effectively reduce the location of vertebral pedicle and the time of nail operation.Conclusion Laser positioning and navigation system is safe and accurate for the application of puncture,nail,biopsy and foreign body removal,including pedicle screw insertion and screw placement.It can be used for reference in other minimally invasive percutaneous operations.