| Objectives: To analyze the stress distribution in the lumbar facet joint afterthoraclumbar kyphosis under4different physiologicalloadings.Methods: A three-dimensional finite element model of the normal human lumbarspine was established.Three spinal segments (L3-S1) were used to investigate andwere modified to simulate5different lordosis of lumbar. The3D finite elementmodels were imported into Ansys software and analyzed.500N pressure was addedon the upper surface of L3, a toque of10Nm moments was loaded to simulate lumbaraxial compression, flexion, extension, and lateral bending.The stress distributions inthe lumbar facet joint were measured and analyzed.Results: In normal lumbar lordosis,under neutral position,the total pressure of bothside of L4/5facet joint is88.52N, under flexion position,the total pressure of bothside of L4/5facet joint is37.21N,under extension position,the total pressure of bothside of L4/5facet joint is104.18N,under the lateral bending position,the total pressureof both side of L4/5facet joint is87.71N,the pressure of right facet joint ismaximum,which is gradually decreased to the contralateral.After the lumbar lordosisis increased of40°,under neutral position,the total pressure of both side of L4/5facetjoint is increased of105.48N, under flexion position,the total pressure of both sideof L4/5facet joint is54.27N,under extension position,the total pressure of both side of L4/5facet joint is151.96N,under the lateral bending position,the total pressure ofboth side of L4/5facet joint is103.62N,the pressure of right facet joint ismaximum,which is gradually decreased to the contralateral.Conclusions: Under the lumbar lordosis compensatory increase, the stressdistribution of lumbar facet joint will change. Though the total stress is almost thesame, the stress on the lumbar facet joint will increase relatively, which remains oneof the mechanism of degenerative changes of lumbar facet joint and low back pain. |
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