Porous fusion cage design via integrated global-local topology optimization and biomechanical analysis of performance

2020 ◽  
Vol 112 ◽  
pp. 103982
Author(s):  
Hongwei Wang ◽  
Yi Wan ◽  
Quhao Li ◽  
Yan Xia ◽  
Xinyu Liu ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Biomechanical Analysis ◽  
Fusion Cage ◽  
Analysis Of Performance ◽  
Local Topology

Biomechanical analysis of combination Ti/PEEK fusion cage designed with topology optimization

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1245-1252
Author(s):  
Hongwei Wang ◽  
Yi Wan ◽  
Xinyu Liu ◽  
Zhanqiang Liu ◽  
Xiao Zhang ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Lumbar Fusion ◽  
Stress Shielding ◽  
Peak Stress ◽  
Biomechanical Analysis ◽  
Shielding Effect ◽  
Peek Cage ◽  
Fusion Procedure ◽  
Cage Subsidence ◽  
Fusion Cage

Fusion cage has been used in lumbar fusion procedure to treat degenerative disc disorders for decades. To address the drawback of Titanium (Ti) and polyetheretherketone (PEEK) cage, a combination Ti/PEEK cage was proposed in present study. Topology optimization was performed to tailor the topological structure of Ti/PEEK cage. The biomechanical performance was comprehensively assessed using finite element method under simulated physiological load conditions. The volume of optimized cage was reduced by 9.7%. The increased volume for bone graft might improve the fusion performance. The lower peak stress was observed on superior and inferior bone endplates of Ti/PEEK cage model, which reduced the risk of cage subsidence. Meanwhile, Ti/PEEK cage effectively reduced the stress shielding effect associated with over-stiffness of Ti cage. In conclusion, the combination Ti/PEEK cage might be a better choice for fusion surgery in relation to Ti or PEEK cage.

The Comparision of Hybrid and Quadrilateral Discretization Models for the Topology Optimization of Compliant Mechanisms

2011 ◽  
Author(s):  
Hong Zhou ◽  
Nitin M. Dhembare
Keyword(s):  
Topology Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Search Space ◽  
Structural Members ◽  
Constraint Violation ◽  
Local Connection ◽  
Hybrid Discretization ◽  
Local Topology ◽  
Design Cell

The design domain of a synthesized compliant mechanism is discretized into quadrilateral design cells in both hybrid and quadrilateral discretization models. However, quadrilateral discretization model allows for point connection between two diagonal design cells. Hybrid discretization model completely eliminates point connection by subdividing each quadrilateral design cell into triangular analysis cells and connecting any two contiguous quadrilateral design cells using four triangular analysis cells. When point connection is detected and suppressed in quadrilateral discretization, the local topology search space is dramatically reduced and slant structural members are serrated. In hybrid discretization, all potential local connection directions are utilized for topology optimization and any structural members can be smooth whether they are in the horizontal, vertical or diagonal direction. To compare the performance of hybrid and quadrilateral discretizations, the same design and analysis cells, genetic algorithm parameters, constraint violation penalties are employed for both discretization models. The advantages of hybrid discretization over quadrilateral discretization are obvious from the results of two classical synthesis examples of compliant mechanisms.

scholarly journals A lattice topology optimization of cervical interbody fusion cage and finite element comparison with ZK60 and Ti-6Al-4V cages

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jun Sun ◽  
Qiuan Wang ◽  
Dazhao Cai ◽  
Wenxiang Gu ◽  
Yiming Ma ◽  
...  
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Topology Optimization ◽  
Bone Graft ◽  
Interbody Fusion ◽  
Stress Shielding ◽  
Shielding Effect ◽  
Cervical Disc ◽  
Significant Difference ◽  
Fusion Cage

Abstract Background In current clinical practice, the most commonly used fusion cage materials are titanium (Ti) alloys. However, titanium alloys are non-degradable and may cause stress shielding. ZK60 is a bio-absorbable implant that can effectively avoid long-term complications, such as stress shielding effects, implant displacement, and foreign body reactions. In this study, we aimed at investigating the biomechanical behavior of the cervical spine after implanting different interbody fusion cages. Methods The finite element (FE) models of anterior cervical disc removal and bone graft fusion (ACDF) with a ZK60 cage and a Ti cage were constructed, respectively. Simulations were performed to evaluate their properties of flexion, extension, lateral bending, and axial rotation of the cervical spine. Moreover, a side-by-side comparison was conducted on the range of motion (ROM), the deformation of cages, the stress in the cages, bone grafts, and cage-end plate interface. Simultaneously, according to the biomechanical analysis results, the microporous structure of the ZK60 cage was improved by the lattice topology optimization technology and validation using static structure. Results The ROMs in the current study were comparable with the results reported in the literature. There was no significant difference in the deformation of the two cages under various conditions. Moreover, the maximum stress occurred at the rear of the cage in all cases. The cage’s and endplate-cage interface’s stress of the ZK60 group was reduced compared with the Ti cage, while the bone graft stress in the ZK60 fusion cage was significantly greater than that in the Ti fusion cage (average 27.70%). We further optimized the cage by filling it with lattice structures, the volume was decreased by 40%, and validation showed more significant biomechanical properties than ZK60 and Ti cages. Conclusion The application of the ZK60 cage can significantly increase the stress stimulation to the bone graft by reducing the stress shielding effect between the two instrumented bodies. We also observed that the stress of the endplate-cage interface decreased as the reduction of the cage’s stiffness, indicating that subsidence is less likely to occur in the cage with lower stiffness. Moreover, we successfully designed a porous cage based on the biomechanical load by lattice optimization.

scholarly journals Design of a Metal 3D Printing Patient-Specific Repairing Thin Implant for Zygomaticomaxillary Complex Bone Fracture Based on Buttress Theory Using Finite Element Analysis

2020 ◽  
Vol 10 (14) ◽  
pp. 4738
Author(s):  
Yu-Tzu Wang ◽  
Chih-Hao Chen ◽  
Po-Fang Wang ◽  
Chien-Tzung Chen ◽  
Chun-Li Lin
Keyword(s):  
Finite Element ◽  
Topology Optimization ◽  
Biomechanical Analysis ◽  
Patient Specific ◽  
Element Analysis ◽  
Posterior Teeth ◽  
Frontal Process ◽  
Metal 3D Printing ◽  
Stress Variations ◽  
Zygomaticomaxillary Complex

This study developed a zygomaticomaxillary complex (ZMC) patient-specific repairing thin (PSRT) implant based on the buttress theory by integrating topology optimization and finite element (FE) analysis. An intact facial skeletal (IFS) model was constructed to perform topology optimization to obtain a hollow skeleton (HS) model with the structure and volume optimized. The PSRT implant was designed based on the HS contour which represented similar trends as vertical buttress pillars. A biomechanical analysis was performed on a ZMC fracture fixation with the PSRT implant and two traditional mini-plates under uniform axial loads applied on posterior teeth with 250 N. Results indicated that the variation in maximum bone stress and model volume between the IFS and HS models was 15.4% and 75.1%, respectively. Small stress variations between the IFS model and repairing with a PSRT implant (2.75–26.78%) were found for compressive stress at frontal process and tensile stress at the zygomatic process. Comparatively, large stress variations (30.67–96.26%) with different distributions between the IFS model and mini-plate models were found at the corresponding areas. This study concluded that the main structure/contour design of the ZMC repair implant according to the buttress position and orientation can obtain a favorable mechanical behavior.

Interbody Fusion Cage Design Using Integrated Global Layout and Local Microstructure Topology Optimization

Spine ◽  
2004 ◽  
Vol 29 (16) ◽  
pp. 1747-1754 ◽  
Author(s):  
Chia-Ying Lin ◽  
Chun-Ching Hsiao ◽  
Po-Quan Chen ◽  
Scott J. Hollister
Keyword(s):  
Topology Optimization ◽  
Interbody Fusion ◽  
Fusion Cage ◽  
Interbody Fusion Cage

Biomechanical analysis and design of a dynamic spinal fixator using topology optimization: a finite element analysis

2014 ◽  
Vol 52 (5) ◽  
pp. 499-508 ◽  
Author(s):  
Hung-Ming Lin ◽  
Chien-Lin Liu ◽  
Yung-Ning Pan ◽  
Chang-Hung Huang ◽  
Shih-Liang Shih ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Topology Optimization ◽  
Biomechanical Analysis ◽  
Element Analysis ◽  
Analysis And Design

scholarly journals Biomechanical Analysis and Design Method for Patient-Specific Reconstructive Implants for Large Bone Defects of the Distal Lateral Femur

Biosensors ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 4
Author(s):  
Po-Kuei Wu ◽  
Cheng-Wei Lee ◽  
Wei-Hsiang Sun ◽  
Chun-Li Lin
Keyword(s):  
Topology Optimization ◽  
Bone Cement ◽  
Fe Analysis ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Internal Cavity ◽  
Solid Core ◽  
Bone Scaffold ◽  
Analysis And Design

This study aims to develop a generalizable method for designing a patient-specific reconstructive scaffold implant for a large distal lateral femur defect using finite element (FE) analysis and topology optimization. A 3D solid-core implant for the distal femur defect was designed to withhold the femur load. Data from FE analysis of the solid implant were use for topology optimization to obtain a ‘bone scaffold implant’ with light-weight internal cavity and surface lattice features to allow for filling with bone material. The bone scaffold implant weighed 69.6% less than the original solid-core implant. The results of FE simulation show that the bone repaired with the bone scaffold implant had lower total displacement (12%), bone plate von Mises stress (34%), bone maximum first principal stress (33%), and bone maximum first principal strain (32%) than did bone repaired with bone cement. The trend in experimental strain with increasing load on the composite femur was greater with bone cement than with the bone scaffold implant. This study presents a generalizable method for designing a patient-specific reconstructive scaffold implant for the distal lateral femur defect that has sufficient strength and space for filling with allograft bone.

scholarly journals Porous Biodegradable Lumbar Interbody Fusion Cage Design and Fabrication Using Integrated Global-Local Topology Optimization With Laser Sintering

2013 ◽  
Vol 135 (10) ◽  
Author(s):  
Heesuk Kang ◽  
Scott J. Hollister ◽  
Frank La Marca ◽  
Paul Park ◽  
Chia-Ying Lin
Keyword(s):  
Topology Optimization ◽  
Lumbar Spine ◽  
Interbody Fusion ◽  
Optimization Technique ◽  
Stress Shielding ◽  
Interconnected Porosity ◽  
Human Lumbar Spine ◽  
Fusion Cage ◽  
Material Layout ◽  
Interbody Fusion Cage

Biodegradable cages have received increasing attention for their use in spinal procedures involving interbody fusion to resolve complications associated with the use of nondegradable cages, such as stress shielding and long-term foreign body reaction. However, the relatively weak initial material strength compared to permanent materials and subsequent reduction due to degradation may be problematic. To design a porous biodegradable interbody fusion cage for a preclinical large animal study that can withstand physiological loads while possessing sufficient interconnected porosity for bony bridging and fusion, we developed a multiscale topology optimization technique. Topology optimization at the macroscopic scale provides optimal structural layout that ensures mechanical strength, while optimally designed microstructures, which replace the macroscopic material layout, ensure maximum permeability. Optimally designed cages were fabricated using solid, freeform fabrication of poly(ε-caprolactone) mixed with hydroxyapatite. Compression tests revealed that the yield strength of optimized fusion cages was two times that of typical human lumbar spine loads. Computational analysis further confirmed the mechanical integrity within the human lumbar spine, although the pore structure locally underwent higher stress than yield stress. This optimization technique may be utilized to balance the complex requirements of load-bearing, stress shielding, and interconnected porosity when using biodegradable materials for fusion cages.

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