[Finite element analysis of bending and standing manipulation in the treatment of lumbosacral joint disorder].

OBJECTIVE:To analyze the displacement, stress and mechanism of lumbosacral joint disorder patients after bending and standing manipulation in the finite element model. METHODS:A three-dimensional finite element model of a patient with lumbosacral joint disorder was established. The finite element analysis method was used to observe and analyze the three loading conditions of the model:axial, 34 degree inclined upward and vertical upward. RESULTS:In the lumbosacral joint disorder model, the L₅ vertebral body was concentrated in the middle of the lower endplate, the intervertebral disc was concentrated in the center of the intervertebral disc, and the stress of S₁ and related structures were concentrated in the anterior and posterior edges of the vertebral body. After simulated manipulation, stress mainly concentrated in the anterior, posterior and central circular areas of L₅ vertebral upper endplate. The posterior structures of vertebral body concentrated in the ventral part of pedicle, isthmus and dorsal part of lamina. The stress of intervertebral disc dispersed in the posterior edge of vertebral body. Displacement results:In the lumbosacral joint disorder model, the left transverse process, the upper and lower articular process and the left part of spinous process were significantly displaced to the left, and the intervertebral disc was protruded forward. After simulated manipulation, the lower notch of L₅ vertebral body moved forward and upward; the area of intervertebral foramen increased; the inferior articular process of L₅ vertebral body moved forward; the superior articular process of sacrum moved forward and downward; the distance of articular process joints increased; and the displacement of sacrum concentrated on the posterior edge of vertebral body and the median sacral crest. CONCLUSIONS:Successful lumbosacral joint modeling can be carried out by finite element analysis, and the mechanism of bending and erecting manipulation is clear, which is effective and safe for the treatment of lumbosacral joint disorders.