Analysis of the Effect of Lumbar Spine Fusion on the Superior Adjacent Intervertebral Disk in the Presence of Disk Degeneration, Using the Three-Dimensional Finite Element Method

Abstract

The purpose of this study was to analyze the effect of lumbar spine fusion on the superior adjacent intervertebral disk in the context of disk degeneration, using a nonlinear three-dimensional finite element method. Detailed L3-L5 motion segment models of normal and degenerated intervertebral disks were developed. In fusion models, L4-L5 was fixed by either posterolateral fusion or posterior lumbar interbody fusion (PLIF). Various loading conditions such as compression loading, compression loading plus flexion moment loading, or compression loading plus extension moment loading were applied to study the corresponding stress. Tresca stress on the posterolateral part of intervertebral annulus fiber and von Mises stress on the vertebral endplate (the superior and inferior sides of L3 and L4) were reduced in all degenerated disk models compared with the normal disk models. The PLIF model showed an increase in the percentage change of stress on the vertebral endplate and on the intervertebral annulus fibrosus when flexion and extension moment loadings were applied. This finding suggests that surgeons should consider the risk of exacerbating degeneration of intervertebral disks by undertaking lumbar spine fusion, when degeneration is found in intervertebral disks adjacent to vertebrae requiring fusion.

Adjacent Segment Degeneration After Lumbar Interbody Fusion With Percutaneous Pedicle Screw Fixation for Adult Low-Grade Isthmic Spondylolisthesis: Minimum 3 Years of Follow-up

“…This has been proven by an observed increase in the intradiscal pressures and segmental motion at the adjacent segment after lumbar arthrodesis. 13,14 Through this alteration, it seems that lumbar arthrodesis contributes to the degeneration of the adjacent segments. 15 However, an alternative theory claims that ASD follows a natural degenerative course in patients who are predisposed.…”

Effects of rod stiffness and fusion mass on the adjacent segments after floating mono-segmental fusion: a study using finite element analysis

“…It has been suspected that the stiffness of the instrumented levels relates directly to increased stress on the cranial adjacent segment and facet joints [10,11]. The increased load over time leads to segmental hypermobility, facet joint hypertrophy, osteophyte formation, and spinal stenosis [12].…”

Design, construction and mechanical testing of digital 3D anatomical data-based PCL–HA bone tissue engineering scaffold

“…In 1988, Geol took advantage of CT geometrical scanning to reconstruct the human digital model, but the meshing accuracy of CT-based digitized human anatomical model was very low, it was difficult to ensure the accuracy of model solution results [26]. With the continuous development of CT and 3D reconstruction, especially the technological innovation of 32-row and over, multi-slice spiral CT and dual-source CT, the CT bone 3D imagingresolution keeps increasing, not only the resolution of field of view (FOV) has been significantly improved, the slice thickness could reach the mm level, providing the possibility towards the digitized reconstruction of CT-based 3D data [27,28].…”

“…Therefore, the cell delivery-based bone repairing technology, which is currently available in clinic, is still limited to the repairing of focal lesions [5]. In recent years, the high polymer-inorganic substances has become the hotspot in the bone tissue engineering (BTE) research because of its biodegradability and easy 3D processing [6], Alothman et al [7] found that the composite of high-density polyethylene (HDPE)-hydroxyapatite (HA) exhibited the tensile strength as up to [22][23][24][25][26][27][28] MPa and the changes of HA content might adjust the characteristic of composite; Zein et al [8] found that the compressive strength of poly-e-caprolactone (PCL) could reach 4-77 MPa, and the yield strength cold reach 0.4-3.6 MPa when the pore size was 160-700 mm and the porosity was 48-77 %, which was much more suitable for the requirements of BTE.…”