Comparison and validation of finite element analysis with a servo-hydraulic testing unit for a biodegradable fixation system in a rabbit model

2014 ◽  
Vol 43 (1) ◽  
pp. 32-39 ◽  
Author(s):  
O. Atali ◽  
A. Varol ◽  
S. Basa ◽  
C. Ergun ◽  
S. Hartomacıoğlu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Rabbit Model ◽  
Hydraulic Testing ◽  
Element Analysis ◽  
Testing Unit ◽  
Fixation System

scholarly journals Finite Element Analysis and Comparative Study of 4 Kinds of Internal Fixation Systems for Anterior Cervical Discectomy and Fusion in Children

2021 ◽  
Author(s):  
ziyu li ◽  
Jianqiang Zhou ◽  
Zhijun Li ◽  
Shaojie Zhang ◽  
xing wang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cervical Spine ◽  
Finite Element Model ◽  
Internal Fixation ◽  
Element Model ◽  
Lower Cervical Spine ◽  
Element Analysis ◽  
Internal Fixation System ◽  
Fixation System

Abstract Background: Spinal injury in children usually occurs in the cervical spine region. Anterior fixation of lower cervical spine has been applied in the treatment of pediatric cervical spine injury and disease due to its stable and firm mechanical properties. This study performed finite element analysis and comparison of 4 different anterior cervical internal fixation systems for children, and explored more stable methods of anterior cervical internal fixation in children. Methods: A finite element model of 6-year-old children with lower cervical spine C4/5 discectomy was established, and the self-designed lower cervical spine anterior locking internal fixation system ACBLP and the children’s anterior cervical internal fixation system ACOP, ACVLP, ACSLP plate screws were fixed and loaded on the model. 27.42N•m torque load was applied to each internal fixation model under 6 working conditions of anteflexion, backward flexion, left flexion, right flexion, left rotation and right rotation, to simulate the movement of the cervical spine. The activity and stress distribution cloud diagram of each finite element model was obtained. Results: In the four internal fixation models of ACOP, ACVLP, ACSLP, and ACBLP, the mobility of C4/5 segment basically showed a decreasing relationship, and the mobility of adjacent segments increased significantly. In the Mises stress cloud diagram of the cervical spine of the four models, the vertebral body and accessories of the ACBLP model born the least stress, followed by ACSLP; The steel plate and screws in the ACVLP internal fixation model were the most stressed; The stress of the internal fixation system (plate/screw) in all models increased in the order of ACBLP, ACSLP, ACVLP, and ACOP.Conclusions: ACBLP internal fixation system had obvious advantages in anterior internal fixation of lower cervical spine in children, C4/5 had the smallest degree of movement, relative displacement was minimal, the stress on the pedicle was the least while the stress on the plate screw was relatively the smallest.

scholarly journals Retropharyngeal Reduction Plate for Treatment of Irreducible Atlantoaxial Dislocation: A Cadaveric Test and Finite Element Analysis

2020 ◽  
Author(s):  
Yukun Du ◽  
Zhao Meng ◽  
Jianyi Li ◽  
Zheng Zhao ◽  
Xiangyang Wang ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Pedicle Screw Fixation ◽  
Atlantoaxial Dislocation ◽  
Element Analysis ◽  
Irreducible Atlantoaxial Dislocation ◽  
Plate System ◽  
Fixation System

Abstract Background: Clinical studies have shown that irreducible atlantoaxial dislocation (IAAD) can achieve reduction, decompression, fixation and fusion by transoral, posterior, and other traditional approaches. The present study aims to introduced a newly designed reduction plate through the retropharyngeal approach and evaluate its feasibility by cadaveric test and finite element analysis.Methods: A cadaveric specimen and a 45-year-old postoperative female patient diagnosed with IAAD who underwent the traditional posterior fixation were enrolled in this scientific study. The retropharyngeal approach involved placing the reduction plate into a cadaveric specimen’s cervical spine. Spiral CT thinly scanning (0.05 mm) from the base of the occipital bone to C7 vertebrae was performed and reconstructed for three-dimensional (3D) finite element analysis using Mimics software based on the Dicom data of two different fixations. Biomechanical distribution was compared between two fixations under different stress conditions, including flexion, extension, bending and rotation, respectively.Results: There was no significant difference in maximum stress between the retropharyngeal reduction plate system and the posterior atlantoaxial pedicle screw fixation system during flexion. Under states of extension, bending and rotation, the maximum stress of the reduction plate system was significantly lower than that of the posterior atlantoaxial pedicle screw fixation system. Both of the maximum stresses between two fixations were far lower than the maximum yield strength (795-827 MPa) and ultimate strength (860-896 MPa) of the titanium alloys. There was no significantly stress concentration between retropharyngeal reduction plate system and the posterior atlantoaxial pedicle screw fixation system under different movement.Conclusions: The cadaveric test showed that it is feasible to place the reduction plate using the retropharyngeal approach. The finite element analysis indicated that the retropharyngeal reduction plate system may provide relatively reliable fixation compared with traditional posterior fixation. A new choice of designing a surgical plan for treating atlantoaxial dislocation is presented.

scholarly journals Finite Element Analysis of the Optimal Configuration of Bridging Combined Internal Fixation System in The Treatment of Vancouver B1 Periprosthetic Femoral Fractures

2021 ◽  
Author(s):  
Long Zhang ◽  
Md Ariful Haque ◽  
Ying Xiong ◽  
Jing Qin ◽  
Luyun Liu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Periprosthetic Fracture ◽  
Femoral Fractures ◽  
Connecting Rod ◽  
Element Analysis ◽  
The Third ◽  
Von Mises ◽  
Internal Fixation System ◽  
Fixation System

Abstract Background and Objective: The incidence of periprosthetic fracture increases with the increase of total hip arthroplasty. The treatment of periprosthetic fracture is always a difficult point. The bridged combined internal fixation system (Ortho-bridge System, OBS) is well adapted to the characteristics of periprosthetic fractures.In this study, finite element analysis was used to evaluate the optimal configuration of OBS for fixation of Vancouver B1 periprosthetic femoral fractures.Methods: A three-rod combination OBS fixation model was established to evaluate the optimal position of the third rod, the cross Angle of proximal screws, the diameter of the connecting rod, and the number of screws. Femoral displacement and the maximum Von Mises (equivalent) stress of OBS were used as evaluation indexes.Results: The third rod is located at 35mm below the lateral fovea of the femur and the minimum Von Mises peak stress of OBS, which is the best location for placing the third rod. It is feasible for proximal screw intersection Angle to be about 71° and 84°.To fix the strength, the 6mm connecting rod is better. Considering the number of screws scheme comprehensively, scheme D is the best number of screws scheme.Conclusion: The personalized and diversified fixation mode of OBS is well adapted to the characteristics of periprosthetic fracture and provides an effective means for the treatment of periprosthetic femoral fracture.

Finite Element Analysis of Distinguish between Two Bone Materials in Femoral Fixation System

2014 ◽  
Vol 915-916 ◽  
pp. 883-886
Author(s):  
Li Min Dong ◽  
Ya Lei Gao ◽  
Wei Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Maximum Stress ◽  
Stress And Strain ◽  
Axial Loads ◽  
Element Analysis ◽  
Bone Material ◽  
Significant Difference ◽  
Single Bone ◽  
Fixation System

This paper deals with the difference of finite element analysis of results between distinguishing bone materials modeling and single bone material modeling. The computed tomography (CT) data was used to build the model that can distinguish cortical bone, cancellous bone of the femur model, together with the plates could be used to set up internal fixation system and do the finite element analysis. The results indicated that the distributions of stress and strain were basically the same, so were the location of the maximum stress and strain. While, except under the axial loads the value of maximum stress and the value of maximum strain showed significant differences. Finally, study reached the conclusion that under the axial loads there were no significant difference between the two methods, thus the single bone material model could be used for easier computing, while, under the other 4 consequences paper recommended distinguishing bone material method for more practical results.

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