scholarly journals Timing of surgery for benign periacetabular tumor: virtual finite element analysis and clinical verification on 39 cases

2020 ◽  
Author(s):  
Hongsheng Yang ◽  
Wenli Zhang ◽  
Yun Lang ◽  
Xiang Fang ◽  
Duan Hong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Risk ◽  
Timing Of Surgery ◽  
Low Risk ◽  
Lesion Group ◽  
Timing Of Operation ◽  
Element Analysis ◽  
Prosthesis Replacement ◽  
Significant Difference

Abstract BackgroundThe treatment of periacetabular tumor has always been met with great challenges, including the lack of a standard for the timing of surgery. The purposes of this study were to predict the risk for fracture by finite element analysis of benign periacetabular tumor; to guide the timing of operation; and to verify the practical application of this standard through clinical cases. MethodsBone defects in different areas of the acetabulum were constructed, and the fracture risk was predicted by finite element analysis. According to the results of finite element analysis and Enneking classification, the patients with benign periacetabular tumor were divided into the low fracture risk noninvasive lesion, low fracture risk invasive lesion, and high fracture risk groups. The grouping was used to guide the timing of operation. ResultsThis study included 39 patients who were followed-up for at least two years to verify the effectiveness of this program. The 12 patients in the low risk noninvasive lesion group that did not undergo operation showed no obvious pathological changes and no pathological fracture; there was no significant difference in the MSTS-93 score between the first and last visits (P > 0.05). The 7 patients in the low risk invasive lesion group were treated with adjuvant therapy before the operation; the MSTS-93 score was significantly lower on the first visit than on the last visit (P < 0.05). The 20 cases that had high risk for fracture underwent surgery after the diagnosis; of these, 13 patients achieved osseointegration of the graft bone and 7 patients had no prosthesis loosening, detachment, displacement or rupture after prosthesis replacement. The MSTS-93 score significantly improved from a preoperative value of 19.61 ± 7.32 to a final follow-up value of 26.28 ± 15.59 (P < 0.01). ConclusionsOur study confirmed that for benign periacetabular tumor, finite element analysis, combined with the nature of the tumor, can predict the risk for acetabular fracture and guide the appropriate timing and method of operation, thereby, enabling a safe therapeutic effect.

scholarly journals Skeletal Microstructure and Estimated Bone Strength Improve Following Parathyroidectomy in Primary Hyperparathyroidism

2017 ◽  
Vol 103 (1) ◽  
pp. 196-205 ◽  
Author(s):  
Natalie E Cusano ◽  
Mishaela R Rubin ◽  
Barbara C Silva ◽  
Yu-Kwang Donovan Tay ◽  
John M Williams ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bone Density ◽  
Primary Hyperparathyroidism ◽  
Fracture Risk ◽  
Bone Strength ◽  
Failure Load ◽  
Mineral Density ◽  
Element Analysis ◽  
Volumetric Bone Density

Abstract Context High-resolution peripheral quantitative computed tomography (HRpQCT) is a noninvasive imaging technology that can provide insight into skeletal microstructure and strength. In asymptomatic primary hyperparathyroidism (PHPT), HRpQCT imaging has demonstrated both decreased cortical and trabecular indices, consistent with evidence for increased fracture risk. There are limited data regarding changes in HRpQCT parameters postparathyroidectomy. Objective To evaluate changes in skeletal microstructure by HRpQCT in subjects with PHPT after parathyroidectomy. Design We studied 29 subjects with PHPT (21 women, 8 men) with HRpQCT at baseline and 6, 12, 18, and 24 months postparathyroidectomy. Main Outcome Measures Volumetric bone mineral density, microarchitectural indices, and finite element analysis at the distal radius and tibia. Results At both the radius and tibia, there were significant improvements in total, cortical, and trabecular volumetric bone density as early as 6 months postparathyroidectomy (24-month values for total volumetric bone density, radius: +2.8 ± 4%, tibia: +4.4 ± 4%; P &lt; 0.0001 for both), cortical thickness (radius: +1.1 ± 2%, tibia: +2.0 ± 3%; P &lt; 0.01 for both), and trabecular bone volume (radius: +3.8 ± 5%, tibia: +3.2 ± 4%; P &lt; 0.0001 for both). At both sites, by finite element analysis, stiffness and failure load were improved starting at 6 months postparathyroidectomy (24-month values for failure load, radius: +6.2 ± 6%, tibia: +4.8 ± 7%; P &lt; 0.0001 for both). Conclusions These results provide information about skeletal microarchitecture in subjects with PHPT followed through 2 years after parathyroidectomy. Estimated bone strength is improved, consistent with data showing decreased fracture risk postparathyroidectomy.

scholarly journals Cluster Analysis of Finite Element Analysis and Bone Microarchitectural Parameters Identifies Phenotypes with High Fracture Risk

2019 ◽  
Vol 105 (3) ◽  
pp. 252-262 ◽  
Author(s):  
Leo D. Westbury ◽  
Clare Shere ◽  
Mark H. Edwards ◽  
Cyrus Cooper ◽  
Elaine M. Dennison ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Cluster Analysis ◽  
Finite Element ◽  
Fracture Risk ◽  
High Fracture ◽  
Element Analysis

Finite Element Analysis of Proximal Femur QCT Scans for the Assessment of Hip Fracture Risk In Older Men

2008 ◽  
Vol 11 (3) ◽  
pp. 467-468 ◽  
Author(s):  
Tony M. Keaveny ◽  
Lynn M. Marshall ◽  
Carrie M. Nielson ◽  
Steven R. Cummings ◽  
Paul F. Hoffmann ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Hip Fracture ◽  
Fracture Risk ◽  
Proximal Femur ◽  
Older Men ◽  
Element Analysis ◽  
Hip Fracture Risk

Fracture risk in the femoral hip region: A finite element analysis supported experimental approach

2012 ◽  
Vol 45 (11) ◽  
pp. 1959-1964 ◽  
Author(s):  
Alexander Tsouknidas ◽  
Kleovoulos Anagnostidis ◽  
Georgios Maliaris ◽  
Nikolaos Michailidis
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Risk ◽  
Experimental Approach ◽  
Element Analysis

Finite element analysis and animal test verification of nitinol alloy iliac vein stent performance

2019 ◽  
Vol 233 (17) ◽  
pp. 6197-6208 ◽  
Author(s):  
HQ Feng ◽  
SB Wang ◽  
YG Wang ◽  
XQ Li ◽  
YJ Mao ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Strength ◽  
Equivalent Stress ◽  
Iliac Vein ◽  
Control Group ◽  
Element Analysis ◽  
Animal Test ◽  
Significant Difference ◽  
Test Verification

The design and fatigue strength of a nitinol iliac vein stent (NIVS) proposed in this study are assessed using the finite element analysis method. The influence of stent diameter and different release scales on its strength, lifespan and biomechanical properties of the vein wall is analyzed for self-developed NIVS of three different diameters (12, 14 and 16mm) and length of 26mm, which were implanted into the corresponding iliac vein with different release scales (80% and 90%). The results obtained strongly indicate that with an increase in the release scale, the equivalent elastic strain, safety factors of fatigue strength, and equivalent stress of the vessel wall exhibit a downward trend, while the most stressed cross-section coincides with the arc of stent-connecting rods. The efficiency and safety of the above stents were verified by in vivo tests (with observation periods of 30, 90 and 180 days after operation) on ten lab pigs, which underwent NIVS implantation into the iliac veins, with observation of hemodynamics, stent deployment, presence/absence of thrombosis, and monitoring of stent lumen loss and its rate. During the animal test verification, the stent release was satisfactory, while the radiography revealed no obvious stent displacement at different time points. In addition, the patency rate of the stent was 100%. Except for the control group, where a small amount of old thrombus was found, other stents exhibited no thrombus; at the same time, there was no significant difference in the lumen loss rate of the stent at each time point. Therefore, the proposed nitinol NIVS samples demonstrated a good performance, accurate positioning, and release, in addition to the reduced risk of lateral iliac vein thrombosis.

Different Structural Integrity Assessment Methods for Pipe Containing Circumferential Through-Thickness Crack

2011 ◽  
Author(s):  
Huifeng Jiang ◽  
Xuedong Chen ◽  
Zhichao Fan
Keyword(s):  
Fracture Toughness ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Integrity ◽  
Load Ratio ◽  
Limit Load ◽  
Element Analysis ◽  
Integrity Assessment ◽  
Significant Difference ◽  
Calculated Load

Heretofore, several kinds of codes are applicable to the structural integrity assessment for pipe containing defects, i.e. API 579, R6 and BS 7910 etc. In this paper, different methods from API 579-1/ASME FFS-1: 2007 and R6-2000 were employed to assess the integrity of pipe containing a circumferential through-thickness crack. However, there was a significant difference between the calculated load ratios by these two codes, although the calculated fracture ratios were very close. To verify these results, elastic-plastic finite element analysis was carried out to calculate the limit load and the load ratio. Additionally, the experimental results and our previous engineering experience were also referred to. The final results imply that the larger load ratio obtained from R6-2000 rather than API 579 code is more reasonable for the pipe with good fracture toughness.

Prediction of Closure Bolt Loads in Small Pressure Vessels: NUREG/CR-6007 vs. Detailed Finite Element Analysis

2010 ◽  
Author(s):  
Charles A. McKeel
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Small Diameter ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Containment Vessel ◽  
Fea Model ◽  
Significant Difference ◽  
Load Increase ◽  
The Difference

Closure bolt loads in a flanged cylindrical containment vessel under internal pressure are determined by detailed Finite Element Analysis (FEA) and compared to values determined using NUREG/CR-6007 equations. The containment vessel is of small diameter with an inwardly dished bolted head that geometrically contrasts with the large, flat lidded casks which the NUREG addressed. The comparison showed a significant difference in the magnitude of pressure driven prying load between the FEA model and the NUREG approximate equations. This difference affected the predicted pressure that overcomes preload, and the rate of load increase after preload was exceeded. The difference was likely due to the contrasts between this vessel’s closure shape compared to the more typical flat cask lid shape used in the NUREG development.

scholarly journals Mechanical and Finite Element Analysis of an Innovative Orthopedic Implant Designed to Increase the Weight Carrying Ability of the Femur and Reduce Frictional Forces on an Amputee’s Stump

2019 ◽  
Vol 184 (Supplement_1) ◽  
pp. 627-636 ◽  
Author(s):  
Tejas P Chillale ◽  
Nam Ho Kim ◽  
Larry N Smith
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Weight Bearing ◽  
Contact Forces ◽  
Element Analysis ◽  
Normal Contact ◽  
Fea Modeling ◽  
Significant Difference ◽  
Frictional Forces ◽  
Weight Carrying

Abstract This study was designed to test the hypothesis that: “A properly designed implant that harnesses the principle of the incompressibility of fluids can improve the weight carrying ability of an amputee’s residual femur and reduce the frictional forces at the stump external socket interface.” The hypothesis was tested both mechanically on an Amputee Simulation Device (ASD) and through Finite Element Analysis (FEA) modeling software. With the implant attached to the femur, the FEA and ASD demonstrated that the femur carried 90% and 93% respectively of the force of walking. Without the implant, the FEA model and ASD femur carried only 35% and 77%, respectively, of the force of walking. Statistical calculations reveal three (3) degrees of separation (99% probability of non-random significant difference) between with and without implant data points. FEA modeling demonstrates that the normal contact forces and shear forces are pushed the distal weight-bearing area of the amputee stump, relieving the lateral stump of frictional forces. The ASD mechanical and FEA modeling data validate each other with both systems supporting the hypotheses with confidence intervals of three degrees of separation between with implant and without implant models.

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