| Objective: To develop a two-way slide guide for pivotal lamina screws based on the anatomical data of the vertebrae,and to explore the safety,accuracy,and deviation factors of the guide lamina cross-screw screw assisted by the guide in vitro and in vivo experiments..Methods This experiment is divided into three partsPart I: Development of Bidirectional Sliding Rail Guide for Pedicle ScrewsThree-dimensional CT data of 40 random patients were selected,and the data was imported into the three-dimensional software for modeling.Nail placement was simulated on the model's pivotal lamina in accordance with the standard nail placement direction.To obtain the distance between the needle point and the upper and lower masses of the vertebral plate.At the same time,the position of the needle point of the laminar nail is locked to simulate the movable angle of the screw end of the laminar screw to obtain a fine adjustment angle.The anatomical data on the left is compared with the anatomical data on the right,and male and female are compared.A three-dimensional model of the guide was designed by combining the pin-out point data,the fine-tuning angle of the guide,and the principle of the concentricity of the slide rail,and the guide entity was produced using 3D printing technology.Part II: Safety and accuracy analysis for in vitro applicationsSelect 40 random three-dimensional CT data from January 2018 to June 2018,19 female patients,including 21 male patients,with an average height of(172.9 ±9.5cm)and an average age of(51.1 ± 12.8 years).Exclude patients with axial lamina defects and hypoplasia.The three-dimensional CT data was imported into the Med CAD module for modeling,and the transparent polyethylene material was used to print out the cervical spine specimens of groups a and b.The 3D printed cervical spine specimens are fully transparent.Group a(40)applies to the guide group,and group b(40)applies to the free-hand nail set.Using a self-made guide to assist in nail placement on group a specimens,insert laminar nails on group b specimens freely,and at the same time reconstruct a three-dimensional model to simulate nail placement on the computer,and measure the dangerous level and screw out of each group Point position and inclination angle.Guider nailing group(Group A: experimental group): use the laminar nail bidirectional slide rail guide to insert the laminar nail on the specimens in group a.The specimens of this nail are made of transparent material and can pass the naked eye Auxiliary vernier calipers were used to evaluate the relationship between the screw and the anterior and posterior cortex of the axial lamina(positional risk level)and the rate of double cortex.Obtain the value of the distance between the needle point and the upper and lower blocks of the axial lamina(the distance between the upper laminar screw and the outer edge of the lateral block L1 and the upper edge L2,the distance between the lower laminar screw and the outer edge of the lateral block L3 and the lower edge L4).And measure the inclination angle of the nail path.Free-hand nailing group(Group B: control group): Lamina nails were placed free-hand on the specimens of group b,and the relationship between the screw and the anterior and posterior cortex of the axial lamina and the double cortical rate were evaluated by visual aided vernier calipers.Obtain the value of the distance between the needle point and the upper and lower blocks of the axial lamina(the distance between the upper laminar screw and the outer edge of the lateral block L1 and the upper edge L2,the distance between the lower laminar screw and the outer edge of the lateral block L3 and the lower edge L4),And measure the inclination angle of the nail path.3D simulation nail placement group(Group C: ideal group): 40 cases of three-dimensional CT in the guide group are selected,and the CT data is reconstructed into a three-dimensional model using reconstruction software.The nail entry point and nail entry angle are selected by the standard nail placement method in the 3D software,Put the simulated laminar nail out of the dorsal cortex of the outer edge of the laminae to obtain the distance between the needle point and the lower and upper masses of the axial lamina(the distance between the upper laminar nail and the outer edge of the lateral mass L1 and the upper edge L2,inferior The distance between the laminar nail and the outer edge of the lateral mass L3 and the lower edge distance L4),and measure the inclination angle of the nail tract.Three sets of anatomical data were statistically analyzed to determine accuracy.Part III: Safety and accuracy analysis of clinical applicationsTen patients who needed posterior atlantoaxial fixation surgery(the pivotal pedicle or vertebral artery deformity could not undergo pedicle screw fixation and no lamina deformity or defect)from December 2018 to January 2020 were selected.Eligible persons use this guider to perform C2 laminar screw placement to complete the fixation operation.After operation,the relationship between the screw and the anterior and posterior cortex of the axial laminae is measured according to X-ray and CT,and the three-dimensional CT data of the above patients are reconstructed on the computer to form a three-dimensional model Simulate nail placement and measure the relationship between the screw and the anterior and posterior cortex of the axial lamina.Each group of data was analyzed statistically to determine accuracy.Clinical application group(Group D): 10 patients with posterior cervical spine fixation surgery from December 2018 to January 2020 were selected,cervical X-rays and CT scans were routinely taken before surgery,and the C2 pedicle was observed and measured For those who cannot perform pedicle screw fixation with pedicle variation,use this guide to perform C2 laminar nail fixation.The relationship between the screw and the anterior and posterior cortex of the vertebral lamina was measured according to X-rays and CT after operation(Figure 3).(Grade 1-5),mark and measure L1: distance between the upper needle exit point and the outer edge of the side block,L2: distance between the upper needle exit point and the upper edge of the side block,L3: distance between the lower needle exit point and the outer edge of the side block L4: The distance between the lower needle exit point and the lower edge of the side block,and the inclination angle of the nail channel.3D simulation nail placement group(Group E: ideal group): 10 patients in the clinical group were selected for 3D CT,and CT data was reconstructed into a 3D model using reconstruction software.In the Med CAD module,a 3 mm diameter cylinder was used instead of the screw.Obtain the nail placement data to simulate the placement of nails,pierce the simulated lamina nails out of the outer edge of the lamina,and measure the needle point.L3: The distance between the lower needle exit point and the outer edge of the side block L4: The distance between the lower needle exit point and the lower edge of the side block,and the inclination angle of the nail channel is measured.The anatomical data of the two groups were analyzed statistically to determine accuracy.ResultsPart I : Needle point data(L1 / L2 / L3 / L4)are 6.44 ± 0.52 mm,7.05 ± 0.48 mm,3.55 ± 0.75 mm,5.09 ± 0.74 mm,and the fine adjustment angle of the slide rail is10.51 ° ± 0.87 °.There was no statistically significant difference between the left and right sides of the two groups of data(P>0.05),and there was no statistically significant difference between the two groups of men and women(P>0.05).In this experiment,through the above anatomical data,the needle point of the spinal lamina nail was used as the marking point,and the principle of the curved slide rail centripetality combined with the anatomical structure of the spinal lamina and spinous process was used to design the auxiliary spinal lamina through 3D printing technology.A two-way slide rail type guide for a vertebral lamina nail inserted with a nail,the guide includes a fixing frame body,a two-way guide sleeve,an arc-shaped centripetal slide rail,a slide rail connecting ring and other parts;the fixing frame body includes an arc shape Bidirectional fixing frame: the upper end is a spinous process locking sleeve,which can be inserted into a Kirschner wire to fix the guide on the spinous process,and the central part is an arc-shaped centripetal slide rail.The guide can be fixed on the slide through the slide rail connecting ring The inside of the rail ensures the centripetality of the sleeve.At the same time,the guide tube is a three-stage sleeve structure,which can complete all nail placement operations.At the same time,in order to obtain better stability,the main body of the guide adopts a metal structure,which can reduce the operation process.Deformation.Part II: In group A,the 80 vertebral lamina nails were acceptable in 75 cases through the observation position in the transparent specimen,the positional risk was 5cases,the acceptance rate was 93%,of which 74 reached the double cortex and the double cortex rate was 92 %.The screw position of group B can be accepted as 62,the positional risk is 18,the acceptance rate is 77%,of which 26 have reached the double cortex,and the rate of double cortex is 32%.There was a statistically significant difference between group A and group B in the location safety level and double cortical rate(P <0.05).The accuracy of the needle exit point of group A is L1 / L2 / L3 / L4: 6.55±0.75 mm,7.61 ± 1.05 mm,3.6 ± 0.84 mm,4.97 ± 0.68 mm,the inclination angle is55.73°±1.54°,the exit of group B Needle point accuracy L1 / L2 / L3 / L4 are 4.71±0.84 mm,6.03 ±0.79 mm,5.11 ± 0.83 mm,6.13±0.58 mm,inclination angle is 51.92°±3.11°,the accuracy of the needle point of group C L1 / L2 / L3 / L4 are 6.44±0.52 mm,7.05±0.48 mm,3.55±0.75 mm,5.09±0.74 mm,and the inclination angle is55.51°±1.62°.The accuracy of the needle point of Group A and C is compared,The difference was not statistically significant(P> 0.05),the accuracy of the needle point of group B and C was compared,the difference was statistically significant(P <0.05),the accuracy of the introversion angle of group A and group C was not statistically different Significance in learning(P> 0.05).The accuracy of the introversion angle between Group A and Group B was statistically significant(P <0.05).Part III: The group of 20 pivotal laminar nails in the d group can accept 75 cases,and the position risk is 5 cases.The acceptable rate is 93%,of which 74 are bicortical,and the rate is 92%.The needle exit point data(L1 / L2 / L3 / L4)of group D were6.17 ± 0.45 mm,6.91 ± 0.98 mm,4.07 ± 0.78 mm,5.11 ± 0.81 mm,and the inclination angle of group D was 54.88 ° ± 1.49 °,The needle point data(L1 / L2 / L3 / L4)of group E are 6.31 ± 0.54 mm,7.115 ± 0.52 mm,3.81 ± 0.91 mm,5.04 ± 0.77 mm,and the inclination angle of group E is 56.69 ° ± 1.65 °.Comparison of the accuracy of the needle point between group D and group E,the difference was not statistically significant(P> 0.05),and the accuracy of the introverted angle between group D and group E(Table 7),the difference was not statistically significant(P> 0.05),ConclusionThe guide has a metal frame structure,structural stability,and the operation does not require repeated perspectives,which can reduce the operation time and reduce the amount of radiation.Due to the reusability,the economy is high.The guide locks the nail entry point and needle exit point at the same time Positioning and guidance,increasing the double cortical rate,and then assisting the two cross-fixation brackets to fix the guide to the spinous process,which can firmly stabilize the guide and avoid guiding errors.Multi-point fixation can ensure that It can also be effectively and accurately guided under conditions.In vitro experiments and clinical application studies have shown that the bidirectional slide rail guide assisted placement of pivotal laminar nails has higher safety and can achieve higher The double cortical rate effectively increases the mechanical strength of the screw placement.At the same time,the precision of the two-way sliding guide of the vertebral plate nails and the inclination angle of the auxiliary nail placement are closer to the ideal nail channel,which has a higher accuracy.Accuracy and safety. |
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