scholarly journals Effects of Bone Cement Distribution On Adjacent Endplates After Percutaneous Vertebroplasty For Thoracolumbar Fractures: A Finite Element Analysis

2021 ◽  
Author(s):  
Ye Han ◽  
Jincheng Wu ◽  
Xiaodong Wang ◽  
Wenshan Gao ◽  
Jianzhong Wang ◽  
...  
Keyword(s):  
Vertebral Body ◽  
Percutaneous Vertebroplasty ◽  
Compression Fracture ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Cement Injection ◽  
Thoracolumbar Region ◽  
Cement Distribution ◽  
Von Mises

Abstract BACKGROUND: Percutaneous vertebroplasty (PVP) is a common surgical method for the treatment of thoracolumbar compression fractures. Currently, no biomechanical analysis has been performed examining the effects of cement distribution and positioning on the overall thoracolumbar range of motion (ROM) and the stress applied to adjacent endplates.METHODS: A model of PVP following vertebral compression fracture was established based on computed tomography data. Cement was injected into the T12 vertebral body. Depending on the location of the injection site, the model was divided into a median cement model, a left cement model, an upper-left cement model, and a lower-left cement model. The postoperative thoracolumbar ROM and biomechanical changes to the adjacent endplates were analyzed.RESULTS: After cement injection, the overall ROM for the thoracolumbar region increased compared with that before cement injection. The maximum ROM of flexion was 9.28° for the left model; the maximum ROM of extension was 10.90° for the upper-left model; the maximum left and right rotations were 8.47° and 8.52°, respectively, for the left model; the maximum left bending was 13.10° for the left model; and the maximum right bending was 13.43° for the left model. The stress applied to the adjacent vertebral endplate in the median cement model increased compared with the intact model, and the von Mises stress (VMS) value changed with different cement positions.CONCLUSION: After cement injection, the overall stress value of the endplate adjacent to the vertebral body increased, and when the position of the cement shifts, the maximum VMS increased further for some positions, and the stress value for the endplate adjacent to the vertebral body increased, which may cause fractures in the relative position.

scholarly journals Effects of Bone Cement Distribution on Adjacent Endplates After Percutaneous Vertebroplasty for Thoracolumbar Fractures: A Finite Element Analysis

2021 ◽  
Author(s):  
Ye Han ◽  
Jincheng Wu ◽  
Xiaodong Wang ◽  
Wenshan Gao ◽  
Jianzhong Wang ◽  
...  
Keyword(s):  
Vertebral Body ◽  
Percutaneous Vertebroplasty ◽  
Compression Fracture ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Cement Injection ◽  
Thoracolumbar Region ◽  
Cement Distribution ◽  
Von Mises

Abstract BACKGROUND: Percutaneous vertebroplasty (PVP) is a common surgical method for the treatment of thoracolumbar compression fractures. Currently, no biomechanical analysis has been performed examining the effects of cement distribution and positioning on the overall thoracolumbar range of motion (ROM) and the stress applied to adjacent endplates.METHODS: A model of PVP following vertebral compression fracture was established based on computed tomography data. Cement was injected into the T12 vertebral body. Depending on the location of the injection site, the model was divided into a median cement model, a left cement model, an upper-left cement model, and a lower-left cement model. The postoperative thoracolumbar ROM and biomechanical changes to the adjacent endplates were analyzed.RESULTS: After cement injection, the overall ROM for the thoracolumbar region increased compared with that before cement injection. The maximum ROM of flexion was 9.28° for the left model; the maximum ROM of extension was 10.90° for the upper-left model; the maximum left and right rotations were 8.47° and 8.52°, respectively, for the left model; the maximum left bending was 13.10° for the left model; and the maximum right bending was 13.43° for the left model. The stress applied to the adjacent vertebral endplate in the median cement model increased compared with the intact model, and the von Mises stress (VMS) value changed with different cement positions.CONCLUSION: After cement injection, the overall stress value of the endplate adjacent to the vertebral body increased, and when the position of the cement shifts, the maximum VMS increased further for some positions, and the stress value for the endplate adjacent to the vertebral body increased, which may cause fractures in the relative position.

scholarly journals The Influence of Pelvic Tilt on Stress Distribution in the Acetabulum: Finite Element Analysis

2020 ◽  
Author(s):  
Kazuhiro Hasegawa ◽  
Tamon Kabata ◽  
Yoshitomo Kajino ◽  
Daisuke Inoue ◽  
Jiro Sakamoto ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Hip Joint ◽  
Tilt Angle ◽  
Pelvic Tilt ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Von Mises

Abstract Background Finite element analysis (FEA) has been previously applied for the biomechanical analysis of acetabular dysplasia and osteotomy. However, until now, there have been little reports on the use of FEA to evaluate the effects of pelvic tilt on stress distribution in the acetabulum. Methods We used the Mechanical Finder Ver. 7.0 (RCCM, Inc., Japan) to construct finite element models based on 3D-CT data of patients, and designed dysplasia, borderline, and normal pelvic models. For analysis, body weight was placed on the sacrum and the load of the flexor muscles of the hip joint was placed on the ilium. The pelvic tilt was based on the anterior pelvic plane, and the pelvic tilt angles were -20°, 0°, and 20°. The load of the flexor muscle of the hip joint was calculated using the moment arm equation.Results All three models showed the highest values of von Mises stress in the -20° pelvic tilt angle, and the lowest in the 20° angle. Stress distribution concentrated in the load-bearing area. The maximum values of von Mises stress in the borderline at pelvic tilt angles of -20° was 3.5Mpa, and in the dysplasia at pelvic tilt angles of 0° was 3.1Mpa. Conclusions The pelvic tilt angle of -20° of the borderline model showed equal maximum values of von Mises stress than the dysplasia model of pelvic tilt angle of 0°, indicating that pelvic retroversion of -20° in borderline is a risk factor for osteoarthritis of the hip joints, similar to dysplasia.

scholarly journals Effects of Pentagonal Pore Sizes in the Zinc Hydroxyapatite Parietal-Temporal Implant

2021 ◽  
Vol 11 (11) ◽  
pp. 76-85
Author(s):  
Wan Nur Fatini Syahirah W. Dagang ◽  
◽  
Nik Harisha Qistina Nik Hamdi ◽  
Shahrul Hisyam Marwan ◽  
Jamaluddin Mahmud ◽  
...  
Keyword(s):  
Pore Size ◽  
Mechanical Performance ◽  
Biomechanical Properties ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Pore Sizes ◽  
Alloplastic Materials ◽  
Cranial Implant ◽  
Von Mises

To reconstruct the fractured skull, affected patients are advised to undergo cranioplasty, which is a surgical procedure to repair the cranial defect by implanting materials such as autologous bone grafts or synthetic alloplastic materials. The use of synthetic alloplastic materials such as hydroxyapatite (HA) has been widely accepted due to their biocompatibility and suitability for larger cranial defects. The zinc hydroxyapatite (ZnHA) material is favourable as HA mimics 60% of the actual human bone, whereas zinc helps to improve its biomechanical properties. The purpose of this study is to construct the ZnHA cranial implant with different pore sizes of 600, 900, and 1200 µm in pentagonal shapes and to study its mechanical performance. At the end of the research, it was found that the implant with a pore size of 900 µm is the most appropriate implant to be utilized without affecting its mechanical performance. Aspects such as the deformation and von Mises stress are discussed to assist on the development of the ZnHA cranial implant. Keywords — Biomechanical analysis, cranial implant, finite element analysis, pore size, zinc hydroxyapatite

scholarly journals Kyphoplasty of Osteoporotic Fractured Vertebrae: A Finite Element Analysis about Two Types of Cement

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Carolin Meyer ◽  
Kerstin van Gaalen ◽  
Tim Leschinger ◽  
Max J. Scheyerer ◽  
Wolfram F. Neiss ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Vertebral Body ◽  
Lumbar Vertebrae ◽  
Von Mises Stress ◽  
Vertebral Compression Fractures ◽  
Stress Concentrations ◽  
Lower Stress ◽  
Element Analysis ◽  
Von Mises

If conservative treatment of osteoporotic vertebral compression fractures fails, vertebro- or kyphoplasty is indicated. Usually, polymethylmethacrylate cement (PMMA) is applied coming along with many disadvantageous features. Aluminum-free glass-polyalkenoate cement (GPC) appears to be a benefit alternative material. This study aimed at comparing the mean stress values in human vertebrae after kyphoplasty with PMMA and GPC (IlluminOss™) at hand of a finite element analysis. Three models were created performing kyphoplasty using PMMA or IlluminOss™, respectively, at two native, human lumbar vertebrae (L4) while one remains intact. Finite element analysis was performed using CT-scans of every vertebra. Moreover the PMMA-treated vertebra was used as a model as analyses were executed using material data of PMMA and of GPC. The unimpaired, spongious bone showed potentials of 0.25 MPa maximally. After augmentation stress levels showed fivefold increase, rising from externally to internally, revealing stress peaks at the ventral border of the spinal canal. At central areas of cement 1 MPa is measured in both types of cement. Around these central areas the von Mises stress decreased about 25-50% (0.5-0.75 MPa). If workload of 500 N was applied, the stress appeared to be more centralized at the IlluminOss™-model, similar to the unimpaired. Considering the endplates the GPC model also closely resembles the unimpaired. Comparing the PMMA-treated vertebral body and the GPC-simulation, there is an obvious difference. While the PMMA-treated model showed a central stress peak of 5 MPa, the GPC-simulation of the same vertebral body presents lower stress of 1.2-2.5 MPa. Finite element analysis showed that IlluminOss™ (GPC), used in kyphoplasty of vertebral bodies, creates lower level stress and strain compared to standardly used PMMA, leading to lower stress concentrations on the cranial and caudal vertebral surface especially. GPC appears to own advantageous biological and clinical relevant features.

scholarly journals The influence of pelvic tilt on stress distribution in the acetabulum: finite element analysis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Kazuhiro Hasegawa ◽  
Tamon Kabata ◽  
Yoshitomo Kajino ◽  
Daisuke Inoue ◽  
Jiro Sakamoto ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Hip Joint ◽  
Tilt Angle ◽  
Pelvic Tilt ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Von Mises

Abstract Background Finite element analysis (FEA) has been previously applied for the biomechanical analysis of acetabular dysplasia and osteotomy. However, until now, there have been little reports on the use of FEA to evaluate the effects of pelvic tilt on stress distribution in the acetabulum. Methods We used the Mechanical Finder Ver. 7.0 (RCCM, Inc., Japan) to construct finite element models based on 3D-CT data of patients, and designed dysplasia, borderline, and normal pelvic models. For analysis, body weight was placed on the sacrum and the load of the flexor muscles of the hip joint was placed on the ilium. The pelvic tilt was based on the anterior pelvic plane, and the pelvic tilt angles were -20°, 0°, and 20°. The load of the flexor muscle of the hip joint was calculated using the moment arm equation. Results All three models showed the highest values of von Mises stress in the -20° pelvic tilt angle, and the lowest in the 20° angle. Stress distribution concentrated in the load-bearing area. The maximum values of von Mises stress in the borderline at pelvic tilt angles of -20° was 3.5Mpa, and in the dysplasia at pelvic tilt angles of 0° was 3.1Mpa. Conclusions The pelvic tilt angle of -20° of the borderline model showed equal maximum values of von Mises stress than the dysplasia model of pelvic tilt angle of 0°, indicating that pelvic retroversion of -20° in borderline is a risk factor for osteoarthritis of the hip joints, similar to dysplasia.

scholarly journals To Evaluate the Influence of Implant Length on Stress Distribution of Osseointegrated Implant: A Three-Dimensional Finite Element Analysis: An In Vitro Study

2018 ◽  
Vol 6 (02/03) ◽  
pp. 097-105
Author(s):  
Neha Jindal ◽  
Manjit Kumar ◽  
Shailesh Jain ◽  
Navjot Kaur ◽  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Biomechanical Analysis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Von Mises ◽  
The Impact ◽  
Implant Length ◽  
Nonsignificant Decrease

AbstractFinite element analysis is a technique for obtaining a solution to a complex mechanical problem by dividing the problem domain into a collection of much smaller and simpler domains (elements) in which the field variables can be interpolated with the use of shape functions. An overall approximated solution to the original problem is determined based on variational principles. Finite element analysis can provide a nondestructive system for quantifying stresses generated at the various interfaces of similar or dissimilar material. The finite element method also allows the study of the internal state of stress of components as well as stress patterns in two or more dissimilar materials adjacent to each other without affecting their independent behavior. This method is therefore ideally suitable for the biomechanical analysis of orthopedic, cardiovascular, and dental structures. In this study, implants of different length were numerically analyzed using bone-implant models developed from computed tomography-generated images of the mandible with osseointegrated implants. The impact of various lengths on stress distribution was examined using implants with a length of 8, 10, and 13 mm in mandibular first molar region under axial load of 100 N and buccolingual load of 50 N. All materials were assumed to be linearly elastic and isotropic. The Statistical Package for the Social Sciences software package was used for statistical analysis. Maximum von Mises stresses were located around the implant neck. It was demonstrated that there was statistically nonsignificant decrease in von Mises stress as the implant length increased. Within the limitations of this study, there was statistically nonsignificant decrease in von Mises stress as the implant length increased.

Percutaneous Vertebroplasty in Osteoporotic Vertebral Body Compression Fracture

2001 ◽  
Vol 44 (2) ◽  
pp. 145 ◽  
Author(s):  
Hyuk Jung Kim ◽  
Seon Kyu Lee ◽  
Hee Young Hwang ◽  
Hyung Sik Kim ◽  
Joon Seok Ko ◽  
...  
Keyword(s):  
Vertebral Body ◽  
Percutaneous Vertebroplasty ◽  
Compression Fracture ◽  
Vertebral Body Compression Fracture

Effects of occlusal scheme on All-on-Four abutments, screws and prostheses: A three-dimensional finite element study

2020 ◽  
Author(s):  
Nurullah Türker ◽  
Hümeyra Tercanlı Alkış ◽  
Steven J Sadowsky ◽  
Ulviye Şebnem Büyükkaplan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Good Prognosis ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Group Function ◽  
Occlusal Contact ◽  
Maximum Deformation ◽  
Contact Points ◽  
Von Mises

An ideal occlusal scheme plays an important role in a good prognosis of All-on-Four applications, as it does for other implant therapies, due to the potential impact of occlusal loads on implant prosthetic components. The aim of the present three-dimensional (3D) finite element analysis (FEA) study was to investigate the stresses on abutments, screws and prostheses that are generated by occlusal loads via different occlusal schemes in the All-on-Four concept. Three-dimensional models of the maxilla, mandible, implants, implant substructures and prostheses were designed according to the All-on-Four concept. Forces were applied from the occlusal contact points formed in maximum intercuspation and eccentric movements in canine guidance occlusion (CGO), group function occlusion (GFO) and lingualized occlusion (LO). The von Mises stress values for abutment and screws and deformation values for prostheses were obtained and results were evaluated comparatively. It was observed that the stresses on screws and abutments were more evenly distributed in GFO. Maximum deformation values for prosthesis were observed in the CFO model for lateral movement both in the maxilla and mandible. Within the limits of the present study, GFO may be suggested to reduce stresses on screws, abutments and prostheses in the All-on-Four concept.

scholarly journals 3D Finite Element Analysis of Rotary Instruments in Root Canal Dentine with Different Elastic Moduli

2021 ◽  
Vol 11 (6) ◽  
pp. 2547 ◽  
Author(s):  
Carlo Prati ◽  
João Paulo Mendes Tribst ◽  
Amanda Maria de Oliveira Dal Piva ◽  
Alexandre Luiz Souto Borges ◽  
Maurizio Ventre ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Root Canal ◽  
Elastic Moduli ◽  
Reaction Force ◽  
Von Mises Stress ◽  
Elastic Behavior ◽  
Element Analysis ◽  
Heat Treated ◽  
Von Mises

The aim of the present investigation was to calculate the stress distribution generated in the root dentine canal during mechanical rotation of five different NiTi endodontic instruments by means of a finite element analysis (FEA). Two conventional alloy NiTi instruments F360 25/04 and F6 Skytaper 25/06, in comparison to three heat treated alloys NiTI Hyflex CM 25/04, Protaper Next 25/06 and One Curve 25/06 were considered and analyzed. The instruments’ flexibility (reaction force) and geometrical features (cross section, conicity) were previously investigated. For each instrument, dentine root canals with two different elastic moduli(18 and 42 GPa) were simulated with defined apical ratios. Ten different CAD instrument models were created and their mechanical behaviors were analyzed by a 3D-FEA. Static structural analyses were performed with a non-failure condition, since a linear elastic behavior was assumed for all components. All the instruments generated a stress area concentration in correspondence to the root canal curvature at approx. 7 mm from the apex. The maximum values were found when instruments were analyzed in the highest elastic modulus dentine canal. Strain and von Mises stress patterns showed a higher concentration in the first part of curved radius of all the instruments. Conventional Ni-Ti endodontic instruments demonstrated higher stress magnitudes, regardless of the conicity of 4% and 6%, and they showed the highest von Mises stress values in sound, as well as in mineralized dentine canals. Heat-treated endodontic instruments with higher flexibility values showed a reduced stress concentration map. Hyflex CM 25/04 displayed the lowest von Mises stress values of, respectively, 35.73 and 44.30 GPa for sound and mineralized dentine. The mechanical behavior of all rotary endodontic instruments was influenced by the different elastic moduli and by the dentine canal rigidity.

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