Study On Fixation Of Unstable Pelvic Fracture With Steel Plate Based On 3D Print Technique Combined With Finite Element Analysis

Through the search of multiple databases,and a large number of literature to check the pelvic fracture,fixed instruments,3D printing technology and the use of materials and finite element analysis to sum up the understanding of 3D printing technology and finite element in the application of pelvic fractures at the same time,And provide the theoretical basis for the next research work.Objective:To establish a pelvic unstable fracture model by 3D printing technique,to simulate the surgical approach,pre-bending steel plate,screw number,length,angle and so on.Methods:volunteers,Zhang,gender:female,age:45 years old,height falls injury,confirmed by CT examination of pelvis without deformity and other lesions.When the routine scan,the patient should take the supine position,head and foot direction,from the highest point of the pelvic iliac crest to the large pelvic tuberosity pelvic,in the Mxview workstation CT section image data thin layer reconstruction(0.5),format DICOM and then in the CT room will bone window and soft tissue window burn disc.The use of Mimics 10.01 software(Materialise,Belgium)for pelvic fracture virtual reduction surgery internal fixation design for preoperative accurate design of surgical programs to provide a reliable basis.The pelvic pelvis 64-slice/256-slice spiral CT scan,collected high-quality layer thickness 0.5 mm,pelvic soft tissue window,DICOM format CT data,DICOM format data into Mimics10.01,using software measurements(measurement)tool for maximum fracture Bit segmentation Segmentation function for three-dimensional reconstruction of different color fragments of bone fragments,with Simulation(simulation)function of virtual fractures broken bone block reset.And then use the Export function to generate the STL format for 3D printing after resetting the pelvic model data.Mimics 10.01 software MedCAD(medical computer aided design)function for virtual internal fixation design,the best position of steel design,the best position of the screw design.In the preoperative simulation operation of the patients on the computer,first of all,the pelvic fracture of the patient in the way of reset,movement distance and rotation angle to carefully understand,and how to avoid the blood vessels during surgery to simulate.The operation of the 3D model was carried out on the individual models of the 3D model,which included the arterial and venous blood vessels and the pelvic fractures.The main contents of the operation were as follows:the surgical approach was determined according to the specific situation of the fracture,the alignment of the fracture block,Use the length of the screw,the number of screws,the position and angle of the nail into the simulation.Results:The model of 3D unstable pelvic fracture was established,and the number,length and placement angle of the screw were simulated.Conclusion:In this part,we study the operation of unstable pelvic fractures by 3D printing technique,including understanding the type of pelvic fracture and the distance of fracture,and through the operation of 3D pelvic fracture model to determine the surgical approach,The number of screws,length,pitch angle and so on.Objective:To analyze the pelvic and internal fixator material properties of the unstable pelvic fracture repair model of 3D,and to add contact pairs.In the finite element analysis software to set the load,constraints,interaction and other conditions.And the finite element analysis of the stress distribution and displacement distribution of the pelvic model of unstable fractures with tension plate was completed.The stress distribution of the bone after repair and the maximum stress.The use of 3D printing technology to reconstruct the pelvic model and simulation of the finite element analysis;Methods:The model of unstable pelvic fracture was completed.The model was analyzed by finite element mesh.The material properties of pelvic and internal fixator were set and the contact pairs were added.In the finite element analysis software to set the load,constraints,interaction and other conditions.And the finite element analysis of stress distribution and displacement distribution of pelvic model with unstable fracture after fixation with internal fixator was completed.The stress distribution of the bone after repair and the maximum stress.Results:The 500N vertical force was applied to the pelvic model.The stress distribution of the pelvic model was not symmetrical and the stress value was 932.4MPa.The pelvic model under the 500N load,the occurrence of smaller strain,pelvic model maximum strain value of 0.0342.Simulated normal body weight,loaded in the pelvic model above the 500N,so that bilateral acetabular fixation,fixed repair after the pelvic model of volunteers in patients with displacement of 1.532.Conclusion:To analyze and establish the finite element models,it was provided to compare the 3D printing combined plate internal fixation treatment with the traditional plate internal fixation treatment by the three-dimensional finite element analysis.Objective:The biomechanical performance advantages of 3D printed steel plate were verified and evaluated by the finite element analysis of the pelvic model in the two groups after the internal fixation treatment in the fourth part.Methods:Retrospective analysis of January 2014-January 2016 in our hospital orthopedic clinical treatment and meet the requirements of the unstable pelvic fracture in 30 patients,male patients in 19 cases,11 cases of female patients,routine examination,to understand Fractures of the details,to avoid misdiagnosis,missed diagnosis at the same time to determine the surgical approach,including the identification of pelvic orthostatic,the entrance of the X-ray,parallel pelvic CT examination.Two groups of patients after admission,after cleaning the wound,the line temporary fixed,that is,pressure bandage.And according to the patient’s injury for debridement suture repair.If the patient’s pelvic posterior ring there is a vertical displacement or associated with lower extremity fractures need to continue bone traction 3-7 days.Group A patients were treated with MIAP.Group B patients were treated with 3D printing technique combined with MIAP for pelvic repair.After the operation,the two groups of patients routinely use antibiotics to prevent infection,and 3-5 days after surgery,according to the specific recovery of patients,to encourage patients to carry out appropriate activities,4-6 weeks after the partial weight walking.3,6,12 months after surgery to the outpatient review,X-ray confirmed fracture after walking only weight walking.The patients were followed up for 1-3 years,and the recovery of the patients and the occurrence of complications were recorded.The operation time,the number of X-ray fluoroscopy,the length of incision,the postoperative Majeed function score and the occurrence of complications were recorded.The experimental data were analyzed using SPSS 19.0 statistical software.Results:The operation time,bleeding volume,incision length and fluoroscopy time were significantly higher in group A than in group B(P<0.05).The rate of Majeed evaluation in group A was significantly lower than that in group B(P<0.05).Two groups of patients were followed up and compared.(P<0.05).The good and good rate of Matta evaluation in group A was significantly lower than that in group B(P<0.05).The time of fracture healing,time of follow-up and free exercise in group A were significantly higher than those in group B There was no major blood vessel or nerve injury in both groups.No postoperative fixation,loosening or rupture occurred.A group of patients with a postoperative incision infection,after repeated dressing wound healing,B group was no patients with wound infection.There was no significant difference in the probability of complications between the two groups(p<0.05).Conclusion:The minimally invasive catheters have the advantages of simple operation,high safety,good reduction of fracture,good radiation received by both doctors and patients,and the use of 3D printing technique combined with minimally invasive catheters to treat pelvic fractures Treatment,the effect obtained by the use of minimally invasive treatment of independent treatment of bone plate,in addition to the operation time,the amount of intraoperative blood loss is further reduced,it is worth to promote in the clinical.Objective:To evaluate the specific efficacy of 3D printing technique in patients with internal fixation using 3D printing technique by finite element analysis.Methods:Two groups of patients in the fourth study were analyzed by finite element analysis.The pelvis was scanned and analyzed by finite element analysis.Perform finite element analysis.SIEMENS’s 64-slice spiral CT machine was used to scan the volunteers,and the three-dimensional reconstruction of the pelvis was performed using the famous 3D reconstruction software Mimics 10.01(Matefialise,Belgium).According to the shape of the internal fixation device,UG(Siemens PLM Sofhvare,Germany)software was used to prepare the internal fixation device.The image is imported into the 3D reverse engineering software Geomagic Studio 12 for surface reconstruction.Iliac and sacral surfaces are irregular,need to manually handle,modify the surface data,make it by the more regular surface composition,otherwise in the future finite element analysis will be wrong.The resulting surface is saved as a SAT format file and output.The SAT format file output in the Geomagic Studio 12 software is imported into a three-dimensional solid model in SolidWorks 2014(Dassault Systemes S.A.,USA).The file is saved and output in X T format.And then the establishment of the pelvic model into a large general finite element analysis software Abaqus 6.11.1(SIMULIA company,France)in the loading,material properties of the assignment and loading operations and other processes.According to the previous part of the method,in the Abaqus the pelvic model of the various parts and internal fixation equipment were carried out the assignment of material properties.And calculated.ResuIts:Three-dimensional finite element analysis was performed on the pelvis of the two groups of patients.Two groups of pelvic models were subjected to bilateral acetabular confinement and 500 N vertical force was applied to the pelvic model above the sacral The stress distribution in the pelvic model of the two groups was not completely symmetrical.The stress distribution of the fixed side was significantly greater than that of the healthy side,and the stress distribution of the two groups appeared at the fracture site,the bending place of the steel plate and the contact area of the screw and the steel plate.The asymmetric distribution of the stress in the model was higher than that in the patients with the pelvic model The maximal strain of the pelvic model was(0.0536 ± 0.0013)mm,and the maximal strain in the 3D group was(0.0343 ± 0.0012)mm.The weight of normal human body was simulated,and the upper loading of the pelvis model of the two groups was up to 500N,which made the bilateral acetabulum fixed.The displacement of the pelvis model of the two volunteers was observed.The displacement of the pelvic model of the normal plate fixation group was(6.782 + 0.01 1)mm,and the displacement of the pelvic model in the 3D group was(2.533 + 0.013)mm.Conclusion:Through the three-dimensional finite element method,the pelvis was analyzed and the weight of normal adult was simulated and analyzed.Finally,it is proved that the stability of 3D printed auxiliary steel plate is better than that of the internal fixation of the pelvis,which proves the reliability of 3D printing technology.