scholarly journals Effect of vertebral degeneration on the instability of spine

2020 ◽  
Vol 60 (2) ◽  
Author(s):  
Olga Chabarova ◽  
Rimantas Kačianauskas ◽  
Vidmantas Alekna
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Lumbar Spine ◽  
Trabecular Bone ◽  
The Finite Element Method ◽  
Lateral Bending ◽  
Spine Stability ◽  
Healthy State ◽  
Cortical Shell ◽  
Vertebral Degeneration

Insufficient exploration of the dependence between diseases of degenerative bones and the range of motion (ROM) during torsion, flexion and lateral bending limits further understanding about the lumbar biomechanics and treating of the lumbar related dysfunction. The objective of this study was to determine the effect of vertebral degradation on the instability of spine 2 motion L2–L4 segments during torsion, flexion and lateral bending by the finite element method (FEM). Three different 3D FE models comprising the healthy state and the degradation of trabecular bone and cortical bone were developed. Nonlinear numerical analyses of lumbar spine stability discovered that osteoporotic degradation can lead to critical segmental ROM and intervertebral shearing values, which results in the loss of spine stability for the case of flexion loading. Instability is caused by microscopic changes in the thickness of cortical shell. This analysis of the intervertebral shearing and ROM may be further used to diagnose such translation abnormalities like hypomobility or hypermobility.

Bone tissue loads around titanium femoral implant and coated with porous layer

2018 ◽  
Vol 2 (90) ◽  
pp. 77-84
Author(s):  
G. Bobik ◽  
J. Żmudzki ◽  
K. Majewska
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Porous Material ◽  
Trabecular Bone ◽  
Cortical Bone ◽  
Bone Tissue ◽  
The Finite Element Method ◽  
Porous Shell ◽  
Cementless Implant ◽  
Trabecular Bone Tissue

Purpose: Difference in the mechanical properties of bone and stiffer femoral implant causes bone tissue resorption, which may result in implant loosening and periprosthetic fractures. The introduction of porous material reduces the stiffness of the implant. The aim of the study was to analyse the influence of porous shell of femoral revision implant on bone tissue loading distribution with use the finite element method. Design/methodology/approach: Load transfer in the femur has been investigated using the finite element method (Ansys). Cementless implant models were placed in the anatomical femur model. Femur model included sponge bone and cortical bone. The solid implant was compared with the implant containing porous material in 70% in outer layer with a thickness of 2 mm. Load of 1500 N during gait was simulated. In addition, the forces of the ilio-tibial band and the abductor muscles were implemented, as well as the torque acting on the implant. Findings: Increase of stress for the porous model was found. The underload zones in bone have been reduced. Loading distribution was slightly more favourable, albeit rather in cortical bone. Stress value in cancellous bone around cementless implant margin has increased to a level that is dangerous for bone loss. Stress in the implant was not dangerous for damage. The stress distribution was different in the implant neck zone where the porous shell borne a little less load and high stress was shifted to the stiffer core. Research limitations/implications: Variable conditions for fitting the stem to the bone as well as the friction conditions were not investigated. Practical implications: Stress values in the spongy bone around the insertion edge of the cementless implant are consistent with long-term clinical results of the bone atrophy in 1 and 2 Gruen`s zones around the fully porous implants. Originality/value: The advantage of fully porous coated implant was the decrease of risk of trabecular bone tissue resorption around the implant tip and the increase of risk of trabecular bone tissue resorption around insertion edge of the implant.

Geometric and Material Property Study of the Human Lumbar Spine Using the Finite Element Method

1992 ◽  
Vol 5 (4) ◽  
pp. 50-59 ◽  
Author(s):  
W. Suwito ◽  
T. S. Keller ◽  
P. K. Basu ◽  
A. M. Weisberger ◽  
A. M. Strauss ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Lumbar Spine ◽  
Material Property ◽  
The Finite Element Method ◽  
Human Lumbar Spine ◽  
Element Method

ASSESSMENT OF THE BIOMECHANICAL COMPATIBILITY OF AN INTERSPINOUS IMPLANT FOR "DYNAMIC STABILIZATION" THROUGH THE FINITE ELEMENT METHOD

2005 ◽  
Vol 05 (02) ◽  
pp. 375-382 ◽  
Author(s):  
R. CONTRO ◽  
P. VENA ◽  
D. GASTALDI ◽  
G. FRANZOSO
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Sagittal Plane ◽  
Compressive Force ◽  
Dynamic Stabilization ◽  
Strength Analysis ◽  
The Finite Element Method ◽  
Biomechanical Compatibility ◽  
Healthy State ◽  
Element Method

The paper addresses the biomechanical compatibility of an interspinous implant used for "dynamic stabilization" of a diseased intervertebral disc. A comparison between the behaviour of a titanium alloy ( Ti 6 Al 4 V ) implant and that of a superelastic alloy ( Ni - Ti ) implant has been carried out. The assessment of the biomechanical compatibility was achieved by means of the finite element method, in which suitably implemented constitutive laws for the materials have been used. The L4–L5 lumbar system in healthy state has been assumed as target for a biomechanically compatible implant. The L4–L5 system with the interspinous implant subjected to compressive force and bending moments has been simulated. A strength analysis for the bearing bone tissue in the posterior processes was also carried out. The results have shown that both implants were able to decrease the force on the apophyseal joints; however, the titanium-based implant exhibited a low biomechanical compatibility under extension-flexion in the sagittal plane; whereas the Ni - Ti exhibited a higher compatibility.

Simulation of tuning graphene plasmonic behaviors by ferroelectric domains for self-driven infrared photodetector applications

Nanoscale ◽  
2019 ◽  
Vol 11 (43) ◽  
pp. 20868-20875 ◽  
Author(s):  
Junxiong Guo ◽  
Yu Liu ◽  
Yuan Lin ◽  
Yu Tian ◽  
Jinxing Zhang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Interfacial Effect ◽  
Infrared Photodetector ◽  
The Finite Element Method ◽  
Ferroelectric Domains ◽  
Element Method

We propose a graphene plasmonic infrared photodetector tuned by ferroelectric domains and investigate the interfacial effect using the finite element method.

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