Topology Optimization Analysis Of Posterior Lumbar Fixation Instrument

Lumbar disc herniation is a common lumbar disease,and with the development of the times have a younger trend,lumbar disc herniation will result in low back pain and numbness and other symptoms.Under the influence of external factors,the nucleus pulposus annulus compressional deformation or damage and the rear side of the spinal nerve root irritation or compression suffered,resulting in corresponding clinical symptoms Lumbar 4-5,lumbar 5-sacral 1 is the most concentrated in the lumbar spine segment.Transforaminal Lumbar Interbody Fusion(TLIF)is the main surgical procedure for unstable lumbar spinal stenosis in lumbar degenerative diseases.Bilateral pedicle screw fixation(bilateral fixation)are now widely used to improve the rate of postoperative fusion for the lumbar instability and bilateral lower extremity neurological symptoms associated.While the posterior approach fusion will result in postoperative epidural fibrosis,paravertebral muscle extensively stripped stretch injury;while over-fixed fusion segment stiffness caused by excessive adjacent nodes segment in the long-term secondary degeneration and produce the corresponding clinical symptoms.while fixed fusion segment stiffness lead to adjacent nodes segment in the long-term secondary degeneration and produce the corresponding clinical symptoms.In this paper,the main content is to model the lumbar and use finite element analysis to optimize the implanted devices.The design of new equipment would meet the support conditions and reduce pedicle screw system stiffness and volume.This study will provide preliminary theoretical support for clinical application.Firstly,a female was used as a model,and the data were acquired by ctscan,then extracted by MIMICS,and the model of L1-L5 lumbar segment was imported into ANSYS and the discs were built according to the data of discs in references,Ansa was used to build a hexahedral model.Secondly,the original vertebral model was verified by ROM comparison with the previous literature.After the initial model was modified,the nucleus pulposus was removed and the pedicle screw system was implanted.The model was called the nail model.Through comparison with the results of other published papers,the feasibility and accuracy of the model are verified.Finally,the maximal pressure of the pedicle screw rod was used as the limiting condition,and the volume of the pedicle screw rod of the nail model was optimized as the objective function.Then the shape was optimized to reduce the volume to obtain the new pedicle screw rod model.The optimized model was re-modeled and compared with the original pedicle rod system to verify the effectiveness of the optimized model.Verified,the new pedicle rod to meet the needs and the volume of rods to reduce the 55%.