Finite Element Analysis Of Lumber Vertebrae Fracture Treating With Pedicle Screw And Three-dimensional Preoperative Design

Purpose:(1) the three dimensional pre-plan of lumbar fracture with pedicle internal fixation;(2) the three dimensional finite element analysis of lumbar fracture treated with pedicle internal fixation.Methods:(1) Volunteers are to anatomical position lie in CT bed, scan data stored in DICOM format. CT data import Boholo in medical image processing software; rebuild produce normal and 3 d model of the fracture spine. Through the different image threshold carefully observe the fracture morphology, location, degree of crush, presence of foreign bodies fall in vertebral canal compression of spinal cord or nerve, the degree of damage assessment of soft tissue;(2) In fully assess basic vital signs and fracture around the bone and soft tissue injury after injury, the software of a transverse, coronal and sagittal identification respectively under three view window and related structure, nailing using Mimics software comes with measuring tools, precision evaluation parameters related to nail;(3) Then the computer aided design software(Solidworks software) design of pedicle screws into the model in STL format. Adjust the direction and point of view, nailing simulation operation process of the pedicle screws into the corresponding location, and observe the location of the pedicle screws and bone structure around relationships, thus determining the screw placement;(4) the action condition are analyzed with the finite element mechanics related parametersResult:(1) the use of the software for conventional CT scanning and the DICOM data generation, 3 d image model accurate reconstruction of the spine related structures, sweeping aside all the nuances of burst fracture structure in front of the clinician. And surrounding tissues of the spine imaging position after fitting, the bony structure of clear observation and the location of the organs and tissues around the relationship and the mutual relationship, and a quick organs, rapid visual evaluation of tissue damage.(2) 11 thoracic pedicle width is 4.34 ~ 4.83 mm, placement Angle of 0 ~ 14.79, in length is 36.10 ~ 51.37 mm; The first lumbar pedicle width 5.57 ~ 671 mm, placement Angle 0 ~ 16.92, 39.13 ~ 52.72 mm in length; Lumbar pedicle width is5.66 ~ 7.32 2 mm, placement Angle 0 ~ 23.96, in 39.28 ~ 51.13 mm length.(3) internal fixation in recumbent force minimum condition, the stress distribution more uniform, Under normal standing operation, the stress in the fracture of internal fixation is relatively small, the stress of the pedicle screws is recumbent state increased about 25%; Stress increased significantly under the stairs action, pedicle and appear stress concentration phenomenon, a lay down under the action of pedicle stress increases about 100%.Conclusion:(1) this research use Boholo medical image processing software can be rapid assessment of injury of injured vertebral auxiliary in medical decisions.(2) Mimics can be used to conduct a preliminary preoperative planning, accurate measurement of pedicle related parameters, auxiliary operation, in order to reduce the occurrence of surgical complications.(3) using the software of finite element model can be established, and analysis of mechanical parameters under various movement of the spine.