Analyses Of Stress And Displacement Of Lumbar Vertebrae During Simulating Sitting-Rotatory Manipulation By Finite Element

Objective1. To explore effects of sitting-rotatory manipulation on inner stress and displacement of lumbar intervertebral disc.2. To explore the mechanism, rationality and security of sitting-rotation manipulation.Method1.The largest forces of thumb on the spinous process of fourth lumbar vertebra were tested and recorded with a press sensor testing system during cracking sounds of the lumbar located and rotatory manipulation.2.Model establishing: one intact fresh young man cadaveric specimens was scanned with CT with 1mm interval through its lumbar vertebrae. Then, the jpg-format data of CT were inputted into computer and were utilized to establish the three-dimensional FEM by using software Mimics. Then the FEM was modified by Freeform system. The finite element system contained of 20781 nodes and 13632 elements.3. Two kinds of sitting-rotation manipulations were decomposed by principium of manipulation. The parameters of mechanics wre analyzed with the three-dimensional finite element system and computed with software Ansys 9. 0.Result1. As the cracking sound , the forces to the fourth spinous process of lumbar vertebra were 4. 98±1. 24kg and 6. 71±1.66kg respectively in left and right thumbs.2. Characteristic of stress, displacement of lumbar disc.lumbar Rotatory Manipulation The stress, displacement of lumbar disc were increasing continuously during manipulation. The stress was concentrated around outlayer of annulus fibrous, which is bigger than the stress in nucleus pulposus. The stress was descended from left-anterior side of the lateral border to right-posterior side of the lateral border in a form of arc. The displacement, just as the stress, descended form left-anterior side of the lateral border to right-posterior side of the lateral border in a form of arc. The displacement of right-posterior region was larger than the left-posterior region.Lumbar Erected and Rotatory Manipulation The stress , displacement of lumbar disc were increasing continuously during manipulation. The stress was descended from right side of the lateral border to left side. The final displacement is increased gradually centered around the right side of nucleus pulposus. The biggest displacement is located at the left side of the lateral border.Conclusion1. By causing the displacement of intervertebral disc and articular process, the manipulation was helpful to relieve the conglutination of nerve toot.2. Cmparing the two kinds of manipulation , the lumbar rotatory manipulation is more effective and safty.