Based On The Finite Element Method To Explore The Influence Of The Lumbar Fixed-point Rotation Reduction Method On The Lumbar Spine Stress After Endoscopic Spinal Nucleus Extraction

Objective: Set up the human body normal lumbar 1-5 segments(L1-5)and endoscopic excision of nucleus pulposus in the spine(PELD)after the three-dimensional finite element model(FEM)of lumbar,lumbar fixed-point rotation analyze the difference in stress changes of the two lumbar spine models under the action of the fixed-point rotation reduction method of the lumbar spine,explain the safety and risk of the fixed-point rotation reduction method of the lumbar spine during postoperative lumbar spine operation,analyze the mechanical effect of the technique and the normal lumbar The operation difference of the posterior lumbar spine.Methods:Collection 1 healthy young volunteers ridge lumbar CT imaging,image through Mimics Geomagic stoudio Solidwork software,such as the mask of image are extracted Smoothing trim reverse build grid cutting and steps to deal with normal lumbar spinal finite element model is set up and verify the validity of the model,the reference based on finite element model of normal lumbar spine after endoscopic excision of nucleus pulposus of lumbar spine model,according to the double chair lumbar fixed-point rotation steps reset method respectively in the ansys software to load working condition of the two models.Results:(1)Established a finite element model of the lumbar spine and verified the validity of the lumbar spine model.(2)Reference literature combined with the morphology of the intervertebral disc after nucleus pulposus to establish a model of nucleus pulposus based on the normal lumbar spine model.(3)In the lumbar fixed-point rotation reduction technique,(1)the stress on the outer edge of the upper and lower lamina of the lumbar spine is greater than the stress inside the lamina.(2)The main stress of the normal and postoperative L4-L5 segments is distributed in the posterior structure.The maximum stress value of the postoperative L4 posterior structure is the largest,with the maximum stress reaching 27.1Mpa.(3)The contact surface between the normal and postoperative model facet joints is mainly located on the rotating side when the manipulation is loaded.The displacement distance of the facet joint in the postoperative L4-5 segment is smaller than that of the normal L4-5 segment,and the postoperative facet joint facet joint stress is greater than the normal L4-5 segments.(4)The displacement trend of the intervertebral disc after operation is similar to that of the normal intervertebral disc,mainly concentrated on the right anterolateral fibrous annulus,and bulges and shifts to the front right.The displacement distance is smaller than that of the normal intervertebral disc.Postoperative nucleus pulposus and intervertebral disc stress were higher than normal intervertebral discs,and the local distribution was uneven.Conclusion(s):(1)During fixed-point rotation reduction of the lumbar spine,the relative displacement of the intervertebral disc or the intervertebral foramen and the nerve root is the main treatment mechanism,and this technique can adjust the relative position of the small joints,loosen the adhesion of the small joints,and correct the disorder of the small joints.(2)During fixed-point rotation reduction of the lumbar spine,the postoperative lumbar facet joint stress increases,prompting the surgeon to realize that the removal of the nucleus pulposus will cause the lumbar spine bearing capacity to be weakened and the facet joint load to increase,and the operation should be strictly control the operation force to avoid facet joint injury.(3)The stress concentration in the pedicle and the spinous process of L4 of the two models was observed by the lumbar fixed point rotation reduction technique,and the maximum stress was within the range of safety values.Therefore,the stress concentration in the facet joint,pedicle and spinous process of the two models could not result in fracture.Therefore,we believed that this technique was safe,but it was not suitable for patients with spondylolysis.(4)Lumbar spine fixed-point rotation reduction technique has reduced therapeutic effect on patients with recurrence after nucleus pulposus removal.Manipulation should be adjusted reasonably according to the clinical situation to avoid aggravating clinical symptoms or complications.