The stress changes of intervertebral disk of degenerative scoliosis after treatment with shortsegment internal fixation and fusion / 中国医师进修杂志

ABSTRACT

Objective To investigate the stress changes of intervertebral disk of degenerative scoliosis (DS) after treatment with short-segment internal fixation and fusion.Methods Based on the DS patient's CT images of the successive spinal column from T12 to superior segment of S1,assigning special material attributes to the model and forming the integrated and effective three dimensional finite element model of DS.Treated with the short-segment (one-segment and two-segment) spinal canal decompression +intervertebral bone fusion+pedicle screw internal fixation.Loading the model on the following posturesanteflexion,postextension,left lateral inclination,right lateral incliniation,left rotation and right rotation.Calculating and analyzing the stress distribution of intervertebral disk and comparing to that of the preoperative normal DS model.Results The stress of intervertebral disk after the short-segment internal fixation and fusion was increased than that of preoperation.The rotation motion affected greater to the upper intervertebral disk of fixation segment and the extension motion affected greater to the inferior intervertebral disk of fixation segment.The increase of stress of upper and inferior intervertebral disk of fixation segment treated with one-segment fixation and fusion(average was 6.03,4.58 MPa,separately) was greater than that of the two-segment fixation and fusion (average was 5.24,4.47 MPa,separately),but there was no statisticdifference (P ＞ 0.05).Conclusions The short-segment intemal fixation can increase the intervertebral disk stress of adjacent segment fixation of DS.The effect on the stress of upper and inferior intervertebral disk of fixation segment of one-segment fixation and fusion is greater than that of two-segment fixation and fusion.And the patient should avoid the rotation and extension movements after treated with the short-segment internal fixation and fusion.