Finite element analysis and design of an interspinous device using topology optimization

Abstract

Recently, interspinous stabilization with Coflex-F implant has become an alternative to treat lumbar spinal stenosis (LSS). However, little attention focused on modifying the structure of the device to obtain the better clinic application. The purpose of this study was to design a new interspinous implant using topology optimization methods and evaluate its biomechanical performance. The finite element models of healthy lumbar spine and surgical lumbar spine with Coflex-F and Coflex-NEW (the new designed implant) were constructed. Finite element analysis was applied to each of the three models. The interspinous implant structure after topology optimization was remodeled at an 8% reduced volume compared with the Coflex-F device, and they can both provide stability in all motion at the surgical segment. Additionally, the advantage of Coflex-NEW was that it can decrease the von Mises stress of the implant structure in flexion, extension, torsion, and the spinous process in flexion, extension, and bending. The stress in spinous process with Coflex-NEW was well-distributed. Graphical abstract ᅟ.

Biomechanical evaluation of strategies for adjacent segment disease after lateral lumbar interbody fusion: is the extension of pedicle screws necessary?

“…Then, ABAQUS software (version 2016, Simulia Inc., USA) was used to set the properties of the lumbar spine components. The material properties were described in the previous literature as specified in Table 1 [16][17][18].…”

“…Utilizing a similar approach to that of Chen et al [21] and Zhong et al [22], a 150 N axial compressive preload was set, and a pure moment of 10 N-m was applied to simulate the model in six directions: (1) flexion (Flx); (2) extension (Ext); (3) left bending (LB); (4) right bending (RB); (5) left rotation (LR); and (6) right rotation (RR). The applied load in this study was deemed to be sufficient to generate maximum physiological motion but was small enough not to harm the specimens according to previous studies [17,21,23]. ABAQUS 2016 software was used for these analyses.…”

Biomechanical evaluation of strategies for adjacent segment disease after lateral lumbar interbody fusion: is the extension of pedicle screws necessary?

“…Then, ABAQUS software (version 2016, Simulia Inc., USA) was used to set the properties of the lumbar spine components. The material properties were described in the previous literature as specified in Table 1 [16][17][18]. The nucleus pulposus and ground substance of the annulus fibrosis were modelled as a homogeneous, hyper-elastic material using the Mooney-Rivlin model [19].…”

“…Utilizing a similar approach to that of Chen et al [21] and Zhong et al [22], a 150 N axial compressive pre-load was set, and a pure moment of 10 N-m was applied to simulate the model in six directions: (1) flexion (Flx); (2) extension (Ext); (3) left bending (LB); (4) right bending (RB); (5) left rotation (LR); and (6) right rotation (RR). The applied load in this study was deemed to be sufficient to generate maximum physiological motion but was small enough not to harm the specimens according to previous studies [17,21,23]. ABAQUS 2016 software was used for these analyses.…”

Biomechanical Evaluation of strategies for Adjacent Segment Disease after Lateral lumbar interbody fusion: is extension of pedicle screw necessary?

“…Then ABAQUS software (version 2016, Simulia Inc., USA) was used to set properties of the lumbar spine components. The material properties were referred to the previous literature as specified in Table 1 [15][16][17]. The nucleus pulposus and ground substance of annulus fibrosis were modeled as a homogeneous, hyper-elastic material using the Mooney-Rivlin model [18].…”