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Nesbitt DQ, Burruel DE, Henderson BS, Lujan TJ. Finite element modeling of meniscal tears using continuum damage mechanics and digital image correlation. Sci Rep 2023; 13:4039. [PMID: 36899069 PMCID: PMC10006193 DOI: 10.1038/s41598-023-29111-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 01/31/2023] [Indexed: 03/12/2023] Open
Abstract
Meniscal tears are a common, painful, and debilitating knee injury with limited treatment options. Computational models that predict meniscal tears may help advance injury prevention and repair, but first these models must be validated using experimental data. Here we simulated meniscal tears with finite element analysis using continuum damage mechanics (CDM) in a transversely isotropic hyperelastic material. Finite element models were built to recreate the coupon geometry and loading conditions of forty uniaxial tensile experiments of human meniscus that were pulled to failure either parallel or perpendicular to the preferred fiber orientation. Two damage criteria were evaluated for all experiments: von Mises stress and maximum normal Lagrange strain. After we successfully fit all models to experimental force-displacement curves (grip-to-grip), we compared model predicted strains in the tear region at ultimate tensile strength to the strains measured experimentally with digital image correlation (DIC). In general, the damage models underpredicted the strains measured in the tear region, but models using von Mises stress damage criterion had better overall predictions and more accurately simulated experimental tear patterns. For the first time, this study has used DIC to expose strengths and weaknesses of using CDM to model failure behavior in soft fibrous tissue.
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Affiliation(s)
- Derek Q Nesbitt
- Biomedical Engineering Doctoral Program, Boise State University, Boise, ID, USA
| | - Dylan E Burruel
- Department of Mechanical and Biomedical Engineering, Boise State University, 1910 University Drive, Boise, ID, 83725-2085, USA
| | - Bradley S Henderson
- Department of Mechanical and Biomedical Engineering, Boise State University, 1910 University Drive, Boise, ID, 83725-2085, USA
| | - Trevor J Lujan
- Department of Mechanical and Biomedical Engineering, Boise State University, 1910 University Drive, Boise, ID, 83725-2085, USA.
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Kirilova-Doneva M, Pashkouleva D. The effects of age and sex on the elastic mechanical properties of human abdominal fascia. Clin Biomech (Bristol, Avon) 2022; 92:105591. [PMID: 35131681 DOI: 10.1016/j.clinbiomech.2022.105591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 12/19/2021] [Accepted: 01/28/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND The abdominal hernias become more prevalent with age, that can adversely affect life quality. The mechanical properties of abdominal wall layers are supposed to play a significant role in developing of an abdominal hernia.The objective of this study was to determine the mechanical properties of the human abdominal layer - fascia and the effects of age and sex on it for choosing the proper brand of hernia mesh. METHODS 78 samples harvested from 19 fresh cadavers were subjected to uniaxial tension tests and divided into four groups according to age. Group A corresponds to age up to 60 years, Group B to age 61-70 years, Group C to age 71-80 years and Group D to 81-90 years. Median stress-stretch ratio curves with respect to age, sex and direction of loading were obtained. Median values of the maximum tensile stress, stretch at maximum stress and elastic modulus calculated at 5% strain were determined. FINDINGS The abdominal fascia showed large variations between specimens depending on age and sex. The stiffness of the fascia increased with age. There is statistically significant differences between the median curves of male samples (P = 0.008) and female samples (P = 0.019) according to age in the L direction. Statistically significant differences between the values of maximum stress (P = 0.01) and elastic modulus (P = 0.003) from Group C in the L direction and maximum stress (P = 0.03) from Group D in the T direction was established. INTERPRETATION The female samples are stiffer than male samples especially after 80 years.
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Affiliation(s)
- Miglena Kirilova-Doneva
- Faculty of Pharmacy, Medical University-Sofia, Sofia, Bulgaria; Institute of Mechanics, Bulgarian Academy of Sciences, Sofia, Bulgaria.
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Eghbali R, Narooei K. A hyperelastic-damage model to study the anisotropic mechanical behavior of coral-hydrogel bio-composite. J Mech Behav Biomed Mater 2021; 126:105054. [PMID: 34933157 DOI: 10.1016/j.jmbbm.2021.105054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 12/11/2021] [Accepted: 12/14/2021] [Indexed: 12/01/2022]
Abstract
In this research, a hyperelastic strain energy function was developed to investigate the anisotropic mechanical behavior of a soft bio-composite containing the coral collagen fibers and alginate hydrogel matrix. This hyperelastic function considers the matrix isotropic response, anisotropic behavior of soft crimpled fibers, and matrix-fiber interaction. The material parameters of the model were assumed as a function of the volume fraction of fibers to consider the fiber content. The published experimental data of matrix and bio-composites with different volume fractions of fibers in different directions were used to find the material parameters. A damage model was developed to take into account the damage of matrix, fibers, and fiber-matrix interaction. Results showed that the interaction contribution increases by increasing the volume fraction of fibers due to the crosslinks between the matrix and fibers. Moreover, by exceeding the fibers volume fraction from 20%, the anisotropic stiffening dominates the interaction stiffening in the longitudinal test owing to the load-bearing of soft fibers. Simulation results exhibited that cross-plied bio-composites show more uniform deformations than angle-plied bio-composites. Moreover, the damage results showed that the matrix plays a significant role in the failure of bio-composites.
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Affiliation(s)
- R Eghbali
- Department of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran, Iran
| | - K Narooei
- Department of Materials Science and Engineering, K. N. Toosi University of Technology, Tehran, Iran.
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Kenja K, Madireddy S, Vemaganti K. Calibration of hyperelastic constitutive models: the role of boundary conditions, search algorithms, and experimental variability. Biomech Model Mechanobiol 2020; 19:1935-1952. [PMID: 32140961 DOI: 10.1007/s10237-020-01318-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 02/20/2020] [Indexed: 11/26/2022]
Abstract
The calibration of hyperelastic constitutive models of soft tissue and tissue surrogates is often treated as an exercise in curve-fitting to the average experimental response, and many of the complicating factors such as experimental boundary conditions and data variability are ignored. In this work, we focus on three questions that arise in this area: the ramifications of ignoring the experimental boundary conditions, the use of local optimizers, and the role of data variability. Using data from a uniaxial extension experiment on a tissue surrogate, we study how these three factors affect the calibration of isotropic hyperelastic constitutive models. Our results show that even with the simplest of constitutive models, it is necessary to look beyond a "good fit" to the average.
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Affiliation(s)
- Krishna Kenja
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, 45221-0072, USA
| | - Sandeep Madireddy
- Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA
| | - Kumar Vemaganti
- Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH, 45221-0072, USA.
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The histological microstructure and in vitro mechanical properties of pregnant and postmenopausal ewe perineal body. ACTA ACUST UNITED AC 2020; 26:1289-1301. [PMID: 31513089 DOI: 10.1097/gme.0000000000001395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE The mechanical properties and microstructure of the perineal body are important for the improvement of numerical models of pelvic organs. We determined the mechanical parameters and volume fractions of the ewe perineal body as an animal model. METHODS The 39 specimens of 13 pregnant swifter ewes delivering by cesarean section (aged 2 years, weight 61.2 ± 6.2 kg (mean ± standard deviation) and 24 specimens of 8 postmenopausal swifter ewes 150 days after surgical ovariectomy (aged 7 years, 58.6 ± 4.6 kg)) were loaded uniaxially to determine Young's moduli of elasticity in the small (E0) and large (E1) deformation regions, and ultimate stresses and strains. The 63 adjacent tissue samples were processed histologically to assess volume fractions of smooth and skeletal muscle, adipose cells, elastin, and type I collagen using a stereological point testing grid. We compared the structural and mechanical differences along the ewe perineal body, and between pregnant and postmenopausal groups. RESULTS The pregnant/postmenopausal perineal body was composed of smooth muscle (12/14%; median), skeletal muscle (12/16%), collagen (10/23%), elastin (8/7%), and adipose cells (6/6%). The E0 was 37/11 kPa (median), E1 was 0.97/1.04 MPa, ultimate stress was 0.55/0.59 MPa, and ultimate strain was 0.90/0.87 for pregnant/postmenopausal perineal body. The perineal body showed a structural and mechanical stability across the sites. The pregnant ewes had a higher amount of skeletal muscle, higher E0, and a less amount of collagen when compared with postmenopausal ewes. CONCLUSIONS The data can be used as input for models simulating vaginal delivery, pelvic floor prolapsed, or dysfunction.
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The histological microstructure and in vitro mechanical properties of the human female postmenopausal perineal body. Menopause 2020; 26:66-77. [PMID: 29994970 DOI: 10.1097/gme.0000000000001166] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The perineal body connects muscles from the pelvic floor and is critical for support of the lower part of the vagina and proper function of the anal canal. We determined mechanical parameters and volume fractions of main components of the human female postmenopausal perineal body. METHODS The specimens were taken from 15 fresh female cadavers (age 74 ± 10, mean ± standard deviation). Seventy-five specimens from five regions of the perineal body were processed histologically to assess volume fractions of tissue components using stereological point testing grid. Fifteen specimens taken from the midline region were loaded uniaxially with 6 mm/min velocity until tissue rupture to determine Young's modulus of elasticity, ultimate stresses, and strains. RESULTS The perineal body was composed of collagen (29%), adipose cells (27%), elastin (7%), smooth muscle (11%), and skeletal muscle (3%). The residual tissue (19%) constituted mostly peripheral nerves, lumina of blood vessels, fibroblasts, and fibrocytes. Young's modulus of elasticity at midline region was 18 kPa (median) at small and 232 kPa at large deformations, respectively. The ultimate stress was 172 kPa and the ultimate strain was 1.4. CONCLUSIONS We determined the structural and mechanical parameters of the perineal body. The resultant data could be used as input for models simulating pelvic floor prolapse or dysfunction.
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Vaidya AJ, Wheatley BB. An experimental and computational investigation of the effects of volumetric boundary conditions on the compressive mechanics of passive skeletal muscle. J Mech Behav Biomed Mater 2019; 102:103526. [PMID: 31877528 DOI: 10.1016/j.jmbbm.2019.103526] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 10/03/2019] [Accepted: 11/06/2019] [Indexed: 12/25/2022]
Abstract
Computational modeling, such as finite element analysis, is employed in a range of biomechanics specialties, including impact biomechanics and surgical planning. These models rely on accurate material properties for skeletal muscle, which comprises roughly 40% of the human body. Due to surrounding tissues, compressed skeletal muscle in vivo likely experiences a semi-confined state. Nearly all previous studies investigating passively compressed muscle at the tissue level have focused on muscle in unconfined compression. The goals of this study were to (1) examine the stiffness and time-dependent material properties of skeletal muscle subjected to both confined and unconfined compression (2) develop a model that captures passive muscle mechanics under both conditions and (3) determine the extent to which different assumptions of volumetric behavior affect model results. Muscle in confined compression exhibited stiffer behavior, agreeing with previous assumptions of near-incompressibility. Stress relaxation was found to be faster under unconfined compression, suggesting there may be different mechanisms that support load these two conditions. Finite element calibration was achieved through nonlinear optimization (normalized root mean square error <6%) and model validation was strong (normalized root mean square error <17%). Comparisons to commonly employed assumptions of bulk behavior showed that a simple one parameter approach does not accurately simulate confined compression. We thus recommend the use of a properly calibrated, nonlinear bulk constitutive model for modeling of skeletal muscle in vivo. Future work to determine mechanisms of passive muscle stiffness would enhance the efforts presented here.
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Affiliation(s)
- Anurag J Vaidya
- Department of Biomedical Engineering, Lewisburg, PA, 17837, USA
| | - Benjamin B Wheatley
- Department of Mechanical Engineering, Bucknell University, 1 Dent Drive, Lewisburg, PA, 17837, USA.
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Ferreira JPS, Rynkevic R, Martins PALS, Parente MPL, Famaey NM, Deprest J, Fernandes AA. Predicting the mechanical response of the vaginal wall in ball burst tests based on histology. J Biomed Mater Res B Appl Biomater 2019; 108:1925-1933. [PMID: 31845527 DOI: 10.1002/jbm.b.34534] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 11/08/2019] [Accepted: 11/21/2019] [Indexed: 12/20/2022]
Abstract
A histologically motivated (HM) coefficient that establishes a link between tissue's microstructure and material model through histological data is used in the prediction of the mechanical properties of vaginal tissue that is subjected to multiaxial loading conditions. Therefore, the material parameters were based on an HM coefficient obtained from tensile testing and histological data of comparable tissues. Uniaxial tensile test data and histological data were collected from three groups of sheep at different time points in their life cycle, including virgins, pregnant, and parous ewes. From this data, a correlation between material parameters and histological data was obtained. Spherical indentation (ball burst [BB]) tests were then performed in specimens with similar tissue structure. The histological data of these samples were used in conjunction with the correlations already established for the uniaxial samples data, to define the material parameters of the BB samples. Mechanical properties of the BB specimens were predicted through basic histology and using finite element modeling (FEM) simulations, without direct mechanical measurements. The predicted force and displacement values of the FEM simulation displayed a good correlation with the experimental (BB) testing results. No fitting of the BB results was performed. In this way, the use of uniaxial tests coupled with useful histological information offers a promising approach to predicting macroscopic material behavior under multiaxial loading conditions in biomechanics.
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Affiliation(s)
- João P S Ferreira
- Mechanical Engineering Department, Faculty of Engineering, University of Porto, Porto, Portugal.,Institute of Science and Innovation in Mechanical and Industrial Engineering, INEGI, Porto, Portugal
| | - Rita Rynkevic
- Mechanical Engineering Department, Faculty of Engineering, University of Porto, Porto, Portugal.,Institute of Science and Innovation in Mechanical and Industrial Engineering, INEGI, Porto, Portugal.,Development and Regeneration Department, Biomedical Sciences, KU Leuven, Leuven, Belgium.,Centre for Surgical Technologies Department, Group Biomedical Sciences, KU Leuven, Leuven, Belgium
| | - Pedro A L S Martins
- Mechanical Engineering Department, Faculty of Engineering, University of Porto, Porto, Portugal.,Institute of Science and Innovation in Mechanical and Industrial Engineering, INEGI, Porto, Portugal
| | - Marco P L Parente
- Mechanical Engineering Department, Faculty of Engineering, University of Porto, Porto, Portugal.,Institute of Science and Innovation in Mechanical and Industrial Engineering, INEGI, Porto, Portugal
| | - Nele M Famaey
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Jan Deprest
- Development and Regeneration Department, Biomedical Sciences, KU Leuven, Leuven, Belgium.,Centre for Surgical Technologies Department, Group Biomedical Sciences, KU Leuven, Leuven, Belgium.,Pelvic Floor Unit, University Hospitals KU Leuven, Leuven, Belgium
| | - António A Fernandes
- Mechanical Engineering Department, Faculty of Engineering, University of Porto, Porto, Portugal.,Institute of Science and Innovation in Mechanical and Industrial Engineering, INEGI, Porto, Portugal
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Rynkevic R, Ferreira J, Martins P, Parente M, Fernandes AA. Linking hyperelastic theoretical models and experimental data of vaginal tissue through histological data. J Biomech 2019; 82:271-279. [PMID: 30466952 DOI: 10.1016/j.jbiomech.2018.10.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/29/2018] [Accepted: 10/31/2018] [Indexed: 10/27/2022]
Abstract
Mechanical characterization of living tissues and computer-based simulations related to medical issues, has become increasingly important to improve diagnostic processes and treatments evaluation. This work proposes a link between the mechanical testing and the material model predictions through histological data of vaginal tissue. Histological data was used to link tensile testing experiments with material-dependent parameters; the approach was adequate to capture the nonlinear response of ovine vaginal tissue over a large strain range. The experimental data obtained on a previous study, has two main components: tensile testing and histological analysis of the ovine vaginal tissue. Uniaxial tensile test data and histological data were collected from three sheep groups: virgins, pregnant and parous. The distal part of vaginal wall was selected since it is prone to tears induced by vaginal delivery. The HGO (Holzapfel-Gasser-Ogden) model parameters were fitted using a stochastic approach, namely the Simple Genetic Algorithm (SGA). The SGA was able to fit the experimental data successfully (R2 > 0.986). The dimensionless coefficient ξ, was highly correlated with histological data. The ratio was seen to increase linearly with increasing collagen content. Coefficient ξ brings a new way of interpreting and understanding experimental data; it connects the nonlinear mechanical behaviour (tensile test) with tissue's morphology (histology). It can be used as an 'inverse' (approximate) method to estimate the mechanical properties without direct experimental measurements, through basic histology. In this context, the proposed methodology appears very promising in estimating the response of the tissue via histological information.
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Affiliation(s)
- Rita Rynkevic
- University of Porto, Faculty of Engineering, Portugal; INEGI, University of Porto, Faculty of Engineering, Portugal; KU Leuven, Department Development and Regeneration, Biomedical Sciences, Leuven, Belgium; Centre for Surgical Technologies, Group Biomedical Sciences, Belgium.
| | - João Ferreira
- University of Porto, Faculty of Engineering, Portugal; INEGI, University of Porto, Faculty of Engineering, Portugal.
| | - Pedro Martins
- University of Porto, Faculty of Engineering, Portugal; INEGI, University of Porto, Faculty of Engineering, Portugal.
| | - Marco Parente
- University of Porto, Faculty of Engineering, Portugal; INEGI, University of Porto, Faculty of Engineering, Portugal.
| | - Antonio A Fernandes
- University of Porto, Faculty of Engineering, Portugal; INEGI, University of Porto, Faculty of Engineering, Portugal.
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Chanda A, Ruchti T, Upchurch W. Biomechanical Modeling of Prosthetic Mesh and Human Tissue Surrogate Interaction. Biomimetics (Basel) 2018; 3:E27. [PMID: 31105249 PMCID: PMC6352698 DOI: 10.3390/biomimetics3030027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 09/09/2018] [Accepted: 09/13/2018] [Indexed: 11/30/2022] Open
Abstract
Surgical repair of hernia and prolapse with prosthetic meshes are well-known to cause pain, infection, hernia recurrence, and mesh contraction and failures. In literature, mesh failure mechanics have been studied with uniaxial, biaxial, and cyclic load testing of dry and wet meshes. Also, extensive experimental studies have been conducted on surrogates, such as non-human primates and rodents, to understand the effect of mesh stiffness, pore size, and knitting patterns on mesh biocompatibility. However, the mechanical properties of such animal tissue surrogates are widely different from human tissues. Therefore, to date, mechanics of the interaction between mesh and human tissues is poorly understood. This work addresses this gap in literature by experimentally and computationally modeling the biomechanical behavior of mesh, sutured to human tissue phantom under tension. A commercially available mesh (Prolene®) was sutured to vaginal tissue phantom material and tested at different uniaxial strains and strain rates. Global and local stresses at the tissue phantom, suture, and mesh were analyzed. The results of this study provide important insights into the mechanics of prosthetic mesh failure and will be indispensable for better mesh design in the future.
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Affiliation(s)
- Arnab Chanda
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA.
- Department of Aerospace Engineering and Mechanics, University of Alabama, Tuscaloosa, AL 35401, USA.
| | - Tysum Ruchti
- Department of Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA.
| | - Weston Upchurch
- Department of Aerospace Engineering and Mechanics, University of Alabama, Tuscaloosa, AL 35401, USA.
- Department of Surgery, University of Minnesota, Minneapolis, MN 55455, USA.
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An investigation into the role of different constituents in damage accumulation in arterial tissue and constitutive model development. Biomech Model Mechanobiol 2018; 17:1757-1769. [PMID: 30058051 DOI: 10.1007/s10237-018-1054-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 07/11/2018] [Indexed: 12/21/2022]
Abstract
Carotid atherosclerotic plaque rupture is one of the leading causes of stroke. Treatments for atherosclerosis can induce tissue damage during the deployment of an intravascular device or through external tissue clamping during surgery. In this paper, a constituent specific study was performed to investigate the role of the ground matrix and collagen fibres of arterial tissue in response to supra-physiological loads. Cyclic mechanical tests were conducted on intact and collagenase-digested strips of porcine common carotid arteries. Using these tests, four passive damage-relevant phenomena were studied, namely (i) Mullins effect, (ii) hysteresis, (iii) permanent set and (iv) matrix failure and fibre rupture. A constitutive model was also developed to capture all of these damage-relevant phenomena using a continuum damage mechanics approach. The implemented constitutive model was fit to experimental results for both intact and digested samples. The results of this work demonstrate the important role of the ground matrix in the permanent deformation of the arterial tissue under high loads. Supra-physiological load-induced tissue damage may play a key role in vascular remodelling in arteries with atherosclerosis or following interventional procedures.
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CHANDA ARNAB, FLYNN ZACHARY, UNNIKRISHNAN VINU. BIOMECHANICAL CHARACTERIZATION OF NORMAL AND PROLAPSED VAGINAL TISSUE SURROGATES. J MECH MED BIOL 2018. [DOI: 10.1142/s0219519417501007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In the recent years, poorly evaluated gynecological surgeries and urogynecological mesh implantations have been affecting millions of women in the US and across the globe. These failed surgeries could be mainly attributed to the nonavailability of vaginal tissues (due to ethical and biosafety issues), which does not allow any experimental testing of operation and mesh implantation techniques before an actual surgery. A surrogate which behaves biomechanically like the human vaginal tissue would be indispensable for simulating surgical suture of vaginal tissues in prolapse surgery, hysterectomy or surgery during traumatic child births (such as Cesarean). Also, vaginal tissue surrogates simulating the various prolapse conditions (such as vaginal tissue stiffening) would be very useful to evaluate tissue modifications due to prolapse, and also mesh and vaginal tissue interactions. In the current work, a low cost four-part silicone-based material was developed, which precisely simulates the linear and nonlinear mechanical behavior of the normal human vaginal tissue. Additionally, a range of four-part silicone-based novel materials were developed which precisely mimics the mechanical behavior of stiffened vaginal tissues at different degrees of prolapse. The linear and nonlinear mechanical behavior of all such novel materials were characterized using elastic and hyperelastic formulations. Such precisely characterized normal and prolapsed vaginal tissue surrogates have not been developed anywhere to date as per the best of our knowledge and would be clinically helpful for gynecological surgical planning in the future.
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Affiliation(s)
- ARNAB CHANDA
- Department of Aerospace Engineering and Mechanics, University of Alabama, Tuscaloosa 35487, USA
| | - ZACHARY FLYNN
- Department of Mechanical Engineering, University of Alabama, Tuscaloosa 35487, USA
| | - VINU UNNIKRISHNAN
- Department of Aerospace Engineering and Mechanics, University of Alabama, Tuscaloosa 35487, USA
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Ramo N, Shetye SS, Puttlitz CM. Damage Accumulation Modeling and Rate Dependency of Spinal Dura Mater. ACTA ACUST UNITED AC 2017; 1:0110061-110068. [DOI: 10.1115/1.4038261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 10/17/2017] [Indexed: 11/08/2022]
Abstract
As the strongest of the meningeal tissues, the spinal dura mater plays an important role in the overall behavior of the spinal cord-meningeal complex (SCM). It follows that the accumulation of damage affects the dura mater's ability to protect the cord from excessive mechanical loads. Unfortunately, current computational investigations of spinal cord injury (SCI) etiology typically do not include postyield behavior. Therefore, a more detailed description of the material behavior of the spinal dura mater, including characterization of damage accumulation, is required to comprehensively study SCI. Continuum mechanics-based viscoelastic damage theories have been previously applied to other biological tissues; however, the current work is the first to report damage accumulation modeling in a tissue of the SCM complex. Longitudinal (i.e., cranial-to-caudal long-axis) samples of ovine cervical dura mater were tensioned-to-failure at one of three strain rates (quasi-static, 0.05/s, and 0.3/s). The resulting stress–strain data were fit to a hyperelastic continuum damage model to characterize the strain-rate-dependent subfailure and failure behavior. The results show that the damage behavior of the fibrous and matrix components of the dura mater are strain-rate dependent, with distinct behaviors when exposed to strain rates above that experienced during normal voluntary neck motion suggesting the possible existence of a protective mechanism.
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Affiliation(s)
- Nicole Ramo
- School of Biomedical Engineering, Colorado State University, 1376 Campus Delivery, Fort Collins, CO 80523-1376
| | - Snehal S. Shetye
- Department of Mechanical Engineering, Colorado State University, 1374 Campus Delivery, Fort Collins, CO 80523-1374
| | - Christian M. Puttlitz
- School of Biomedical Engineering, Department of Mechanical Engineering, Department of Clinical Sciences, Colorado State University, 1374 Campus Delivery, Fort Collins, CO 80523-1374
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Chanda A, Unnikrishnan V, Richter HE, Lockhart ME. A biofidelic computational model of the female pelvic system to understand effect of bladder fill and progressive vaginal tissue stiffening due to prolapse on anterior vaginal wall. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2016; 32:e02767. [PMID: 26732347 DOI: 10.1002/cnm.2767] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 12/23/2015] [Accepted: 12/27/2015] [Indexed: 06/05/2023]
Abstract
Treatment of anterior vaginal prolapse (AVP), suffered by over 500,000 women in the USA, is a challenge in urogynecology because of the poorly understood mechanics of AVP. Recently, computational modeling combined with finite element method has been used to model AVP through the study of pelvic floor muscle and connective tissue impairments on the anterior vaginal wall (AVW). Also, the effects of pelvic organ displacements on the AVW were studied numerically. In our current work, an MRI-based full-scale biofidelic computational model of the female pelvic system composed of the urinary bladder, vaginal canal, and the uterus was developed, and a novel finite element method framework was employed to simulate vaginal tissue stiffening and also bladder filling due to expansion for the first time. A mesh convergence study was conducted to choose a computationally efficient mesh, and a non-linear hyperelastic Yeoh's material model was adopted for the study. The AVW displacements, mechanical stresses, and strains were estimated at varying degrees of bladder fills and vaginal tissue stiffening. Both bladder filling and vaginal stiffening were found to increase the stress concentration on the AVW with varying trends, which have been discussed in detail in the paper. To our knowledge, this study is the first to estimate the individual and combined effects of bladder filling and vaginal tissue stiffening due to prolapse on the AVW. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Arnab Chanda
- Department of Aerospace Engineering and Mechanics, University of Alabama, Tuscaloosa, 35487, AL, USA
| | - Vinu Unnikrishnan
- Department of Aerospace Engineering and Mechanics, University of Alabama, Tuscaloosa, 35487, AL, USA.
| | - Holly E Richter
- Division of Urogynecology and Pelvic Reconstructive Surgery, Department of Obstetrics and Gynecology, University of Alabama at Birmingham, 1720 2nd Ave S, Birmingham, AL, 35233, USA
| | - Mark E Lockhart
- Department of Radiology, University of Alabama at Birmingham, 1720 2nd Ave S, Birmingham, AL, 35233, USA
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Li W, Luo X. An Invariant-Based Damage Model for Human and Animal Skins. Ann Biomed Eng 2016; 44:3109-3122. [PMID: 27066788 PMCID: PMC5042997 DOI: 10.1007/s10439-016-1603-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 03/31/2016] [Indexed: 11/29/2022]
Abstract
Constitutive modelling of skins that account for damage effects is important to provide insight for various clinical applications, such as skin trauma and injury, artificial skin design, skin aging, disease diagnosis, surgery, as well as comparative studies of skin biomechanics between species. In this study, a new damage model for human and animal skins is proposed for the first time. The model is nonlinear, anisotropic, invariant-based, and is based on the Gasser-Ogden-Holzapfel constitutive law initially developed for arteries. Taking account of the mean collagen fibre orientation and its dispersion, the new model can describe a wide range of skins with damage. The model is first tested on the uniaxial test data of human skin and then applied to nine groups of uniaxial test data for the human, swine, rabbit, bovine and rhino skins. The material parameters can be inversely estimated based on uniaxial tests using the optimization method in MATLAB with a root mean square error ranged between 2.15% and 12.18%. A sensitivity study confirms that the fibre orientation dispersion and the mean fibre angle are among the most important factors that influence the behaviour of the damage model. In addition, these two parameters can only be reliably estimated if some histological information is provided. We also found that depending on the location of skins, the tissue damage may be brittle controlled by the fibre breaking limit (i.e., when the fibre stretch is greater than 1.13-1.32, depending on the species), or ductile (due to both the fibre and the matrix damages). The brittle damages seem to occur mostly in the back, and the ductile damages are seen from samples taken from the belly. The proposed constitutive model may be applied to various clinical applications that require knowledge of the mechanical response of human and animal skins.
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Affiliation(s)
- Wenguang Li
- School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Xiaoyu Luo
- School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8QW, UK
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16
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Abstract
Damage to soft tissues in the human body has been investigated for applications in healthcare, sports, and biomedical engineering. This paper reviews and classifies damage models for soft tissues to summarize achievements, identify new directions, and facilitate finite element analysis. The main ideas of damage modeling methods are illustrated and interpreted. A few key issues related to damage models, such as experimental data curve-fitting, computational effort, connection between damage and fractures/cracks, damage model applications, and fracture/crack extension simulation, are discussed. Several new challenges in the field are identified and outlined. This review can be useful for developing more advanced damage models and extending damage modeling methods to a variety of soft tissues.
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Affiliation(s)
- Wenguang Li
- School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
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17
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Hou M, Wu Q, Dai M, Xu P, Gu C, Jia X, Feng J, Mo X. Fabrication of electrospun thermoplastic polyurethane blended poly (l-lactide-co-e-caprolactone) microyarn scaffolds for engineering of female pelvic-floor tissue. Biomed Mater 2014; 10:015005. [DOI: 10.1088/1748-6041/10/1/015005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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García A, Martínez MA, Peña E. Determination and modeling of the inelasticity over the length of the porcine carotid artery. J Biomech Eng 2014; 135:31004. [PMID: 24231815 DOI: 10.1115/1.4023371] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 01/10/2013] [Indexed: 11/08/2022]
Abstract
The study of the mechanical properties of swine carotids has clinical relevance because it is important for the appropriate design of intravascular devices in the animal trial phases. The inelastic properties of porcine carotid tissue were investigated. Experimental uniaxial cyclic tests were performed along the longitudinal and circumferential directions of vessels. The work focused on the determination, comparison, and constitutive modeling of the softening properties and residual stretch set of the swine carotid artery over long stretches and stress levels in both proximal and distal regions. It was observed that the residual strain depends on the maximum stretch in the previous load cycle. The strain was higher for distal than for proximal samples and for circumferential than for longitudinal samples. In addition, a pseudoelastic model was used to reproduce the residual stretch and softening behavior of the carotid artery. The model presented a good approximation of the experimental data. The results demonstrate that the final results in animal trial studies could be affected by the location studied along the length of the porcine carotid.
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Chen B, Dave B. Challenges and Future Prospects for Tissue Engineering in Female Pelvic Medicine and Reconstructive Surgery. Curr Urol Rep 2014; 15:425. [DOI: 10.1007/s11934-014-0425-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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20
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Trajkovski A, Omerović S, Hribernik M, Prebil I. Failure Properties and Damage of Cervical Spine Ligaments, Experiments and Modeling. J Biomech Eng 2014; 136:031002. [DOI: 10.1115/1.4026424] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 01/06/2014] [Indexed: 11/08/2022]
Abstract
Cervical spine ligaments have an important role in providing spinal cord stability and restricting excessive movements. Therefore, it is of great importance to study the mechanical properties and model the response of these ligaments. The aim of this study is to characterize the aging effects on the failure properties and model the damage of three cervical spine ligaments: the anterior and the posterior longitudinal ligament and the ligamentum flavum. A total of 46 samples of human cadaveric ligaments removed within 24–48 h after death have been tested. Uniaxial tension tests along the fiber direction were performed in physiological conditions. The results showed that aging decreased the failure properties of all three ligaments (failure load, failure elongation). Furthermore, the reported nonlinear response of cervical ligaments has been modeled with a combination of the previously reported hyperelastic and damage model. The model predicted a nonlinear response and damage region. The model fittings are in agreement with the experimental data and the quality of agreement is represented with the values of the coefficient of determination close to 1.
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Affiliation(s)
- Ana Trajkovski
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva cesta 6, Ljubljana 1000, Slovenia e-mail:
| | - Senad Omerović
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva cesta 6, Ljubljana 1000, Slovenia e-mail:
| | - Marija Hribernik
- Medical Faculty, University of Ljubljana, Vrazov trg 2, Ljubljana 1000, Slovenia e-mail:
| | - Ivan Prebil
- Faculty of Mechanical Engineering, University of Ljubljana, Aškerčeva cesta 6, Ljubljana 1000, Slovenia e-mail:
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21
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Hernández-Gascón B, Grasa J, Calvo B, Rodríguez JF. A 3D electro-mechanical continuum model for simulating skeletal muscle contraction. J Theor Biol 2013; 335:108-18. [PMID: 23820034 DOI: 10.1016/j.jtbi.2013.06.029] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 06/10/2013] [Accepted: 06/20/2013] [Indexed: 11/25/2022]
Abstract
A thermodynamically consistent three-dimensional electro-mechanical continuum model for simulating skeletal muscle contraction is presented. Active and passive responses are accounted for by means of a decoupled strain energy function into passive and active contributions. The active force is obtained as the maximum tetanic force penalized by two functions that consider the external stimulus frequency and the overlap between actin and myosin filaments. Passive response is modelled by a transversely isotropic strain energy function. The robustness of the model is analyzed by means of finite element simulations that reproduce the one-dimensional isometric, concentric and eccentric contractions in a simplified model of a muscle. The model has also been implemented to reproduce isometric and concentric contractions on a three-dimensional finite element model of the rat tibialis anterior (TA) muscle. The finite element model was obtained from magnetic resonance imaging and the preferential directions associated with the collagen and muscular fibres were considered. The proposed model was able to reproduce the observed experimental response of the active force generated by the isolated rat TA muscle during isometric and concentric contractions. In addition, the predicted force-velocity relationship is in good agreement with experimental data reported for the fast-twitch extensor digitorum longus (e.d.l) muscle of male rats.
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Affiliation(s)
- B Hernández-Gascón
- Aragón Institute of Engineering Research. University of Zaragoza, Ed. Betancourt, C/ Maria de Luna s/n 50018 Zaragoza, Spain.
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22
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Hernández-Gascón B, Peña E, Grasa J, Pascual G, Bellón JM, Calvo B. Mechanical Response of the Herniated Human Abdomen to the Placement of Different Prostheses. J Biomech Eng 2013; 135:51004. [DOI: 10.1115/1.4023703] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 02/19/2013] [Indexed: 01/02/2023]
Abstract
This paper describes a method designed to model the repaired herniated human abdomen just after surgery and examine its static mechanical response to the maximum intra-abdominal pressure provoked by a physiological movement (standing cough). The model is based on the real geometry of the human abdomen bearing a large incisional hernia with several anatomical structures differentiated by MRI. To analyze the outcome of hernia repair, the surgical procedure was simulated by modeling a prosthesis placed over the hernia. Three surgical meshes with different mechanical properties were considered: an isotropic heavy-weight mesh (Surgipro®), a slightly anisotropic light-weight mesh (Optilene®), and a highly anisotropic medium-weight mesh (Infinit®). Our findings confirm that anisotropic implants need to be positioned such that the most compliant axis of the mesh coincides with the craneo-caudal direction of the body.
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Affiliation(s)
| | | | - Jorge Grasa
- Associate Professor e-mail: Aragón Institute of Engineering Research (I3A), University of Zaragoza, CIBER-BBN, Centro de Investigación en Red en Bioingeniería, Biomateriales y Nanomedicina, Zaragoza 50018, Spain
| | - Gemma Pascual
- Associate Professor Faculty of Medicine, Department of Medical Specialities, University of Alcalá, CIBER-BBN, Centro de Investigación en Red en Bioingeniería, Biomateriales y Nanomedicina, Alcalá 28871, Spain e-mail:
| | - Juan M. Bellón
- Professor Faculty of Medicine, Department of Surgery, University of Alcalá, CIBER-BBN, Centro de Investigación en Red en Bioingeniería, Biomateriales y Nanomedicina, Alcalá 28871, Spain e-mail:
| | - Begoña Calvo
- Professor Aragón Institute of Engineering Research (I3A), University of Zaragoza, CIBER-BBN, Centro de Investigación en Red en Bioingeniería, Biomateriales y Nanomedicina, Zaragoza 50018, Spain e-mail:
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23
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Martins P, Lopes Silva-Filho A, Rodrigues Maciel da Fonseca AM, Santos A, Santos L, Mascarenhas T, Natal Jorge RM, Ferreira AJM. Biomechanical properties of vaginal tissue in women with pelvic organ prolapse. Gynecol Obstet Invest 2012; 75:85-92. [PMID: 23295833 DOI: 10.1159/000343230] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 08/23/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS To compare biomechanical properties of vaginal tissues between women with and without pelvic organ prolapse (POP) and investigate factors that may influence these properties. METHODS Forty patients submitted to POP surgery and 15 non-POP cadavers were evaluated. The tissue was excised from anterior and posterior middle third vagina. The biomechanical properties considered were stiffness (E) and maximum stress (S), and they were evaluated by means of uniaxial tension tests. RESULTS POP patients were associated with higher values of E (13.1 ± 0.8 vs. 9.5 ± 0.7 MPa; p < 0.001) and S (5.3 ± 0.5 vs. 3.2 ± 0.9 MPa; p < 0.001) in the anterior vaginal wall compared to the posterior wall. In contrast, non-POP women presented lower values of E (6.9 ± 1.1 vs. 10.5 ± 1.0 MPa; p = 0.01) and S (2.6 ± 0.4 vs. 3.5 ± 0.4 MPa; p = 0.043) in the anterior wall. The occurrence of POP was the only independent predictor of higher values of E and S in anterior vaginal samples (p = 0.003 and p = 0.008, respectively). Women with severe anterior vaginal prolapse presented higher levels of E and S in the anterior sample compared to those with lower POP stages (p = 0.001 and p = 0.01; respectively). CONCLUSION Women with POP present significant changes of biomechanical properties in the vagina.
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Affiliation(s)
- Pedro Martins
- Department of Gynecology and Obstetrics, Faculty of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil
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24
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Forsell C, Swedenborg J, Roy J, Gasser TC. The Quasi-Static Failure Properties of the Abdominal Aortic Aneurysm Wall Estimated by a Mixed Experimental-Numerical Approach. Ann Biomed Eng 2012; 41:1554-66. [DOI: 10.1007/s10439-012-0711-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 11/20/2012] [Indexed: 10/27/2022]
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25
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Hernández-Gascón B, Mena A, Peña E, Pascual G, Bellón JM, Calvo B. Understanding the Passive Mechanical Behavior of the Human Abdominal Wall. Ann Biomed Eng 2012; 41:433-44. [DOI: 10.1007/s10439-012-0672-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 09/29/2012] [Indexed: 02/05/2023]
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26
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Mechanical characterization and constitutive modelling of the damage process in rectus sheath. J Mech Behav Biomed Mater 2012; 8:111-22. [DOI: 10.1016/j.jmbbm.2011.12.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 11/26/2011] [Accepted: 12/16/2011] [Indexed: 11/23/2022]
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27
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Marini G, Maier A, Reeps C, Eckstein HH, Wall WA, Gee MW. A continuum description of the damage process in the arterial wall of abdominal aortic aneurysms. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2012; 28:87-99. [PMID: 25830207 DOI: 10.1002/cnm.1472] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In the present work, we develop a three-dimensional isotropic finite-strain damage model for abdominal aortic aneurysm (AAA) wall that considers both the characteristic softening of the material caused by damage and the spatial variation of the material properties. A strain energy function is formulated that accounts for a hyperelastic, slightly compressible, isotropic material behavior during the elastic phase, whereas the damage process only contributes to the material response when the elastic limit of the AAA wall is exceeded. Material and damage parameters are obtained by fitting the strain energy function to the experimental data obtained by uniaxial tensile tests of freshly harvested AAA wall samples. The damage model extends the validity of the material law to a strain range of up to 50%. Purely elastic material laws for AAA wall are only valid for a strain range of up to 17%. In a series of finite element simulations of patient-specific AAAs, serving as numerical examples, we investigate the applicability of the damage model. The use of the damage model does not yield a more distinct identification of rupture-prone AAAs than other computational-based risk indices. However, the benefit of the finite-strain damage model is the potential capability to trigger growth and remodeling processes in mechanobiological models.
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Affiliation(s)
- Giacomo Marini
- 1Swiss Federal Institute of Technology (ETH), Institute for Biomechanics, HCI E 355.1, Zurich 8093, Switzerland
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28
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An irreversible constitutive model for fibrous soft biological tissue: a 3-D microfiber approach with demonstrative application to abdominal aortic aneurysms. Acta Biomater 2011; 7:2457-66. [PMID: 21338718 DOI: 10.1016/j.actbio.2011.02.015] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 01/18/2011] [Accepted: 02/09/2011] [Indexed: 11/21/2022]
Abstract
Understanding the failure and damage mechanisms of soft biological tissue is critical to a sensitive and specific characterization of tissue injury tolerance and its relation to biological responses. Despite increasing experimental and analytical efforts, failure-related irreversible effects of soft biological tissue are still poorly understood. There is still no clear definition of what "damage" of a soft biological material is, and conventional macroscopic indicators, as known from damage of engineering materials for example, may not identify the tissue's tolerance to injury appropriately. To account for the complex three-dimensional arrangement of collagen, a microfiber model approach is applied, where constitutive relations for collagen fibers are integrated over the unit sphere, which in turn defines the tissue's macroscopic properties. A collagen fiber is represented by a bundle of proteoglycan cross-linked collagen fibrils that undergoes irreversible deformations when exceeding its elastic tensile limit. The proposed constitutive model is able to predict strain stiffening at physiological strain levels and does not exhibit a clear macroscopic elastic limit, two typical features known from soft biological tissue testing. An elastic-predictor/plastic-corrector implementation of the model is followed and constitutive parameters are estimated from in vitro test data from a particular abdominal aortic aneurysm (AAA). Damage-based structural instabilities of the AAA under different inflation conditions are investigated, where the collagen orientation density has been estimated from its in vivo stress state.
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29
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Martins PA, Jorge RMN, Ferreia AJ, Saleme CS, Roza T, Parente MM, Pinotti M, Mascarenhas T, Santos A, Santos L, Silva-Filho AL. Vaginal Tissue Properties versus Increased Intra-Abdominal Pressure: A Preliminary Biomechanical Study. Gynecol Obstet Invest 2011; 71:145-50. [DOI: 10.1159/000315160] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Accepted: 05/05/2010] [Indexed: 11/19/2022]
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30
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Ochoa I, Peña E, Andreu EJ, Pérez-Ilzarbe M, Robles JE, Alcaine C, López T, Prósper F, Doblaré M. Mechanical properties of cross-linked collagen meshes after human adipose derived stromal cells seeding. J Biomed Mater Res A 2010; 96:341-8. [PMID: 21171153 DOI: 10.1002/jbm.a.32988] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 09/15/2010] [Accepted: 09/17/2010] [Indexed: 11/08/2022]
Abstract
The main goal of this study was to evaluate the potential of collagen meshes derived from porcine dermis as scaffolds for repairing pelvic organ prolapses. Mechanical properties of collagen meshes with different cross-linking percentages before and after Adipose Derived Stromal Cells (ADSC) seeding were studied as well as the cell-scaffold interaction. Uniaxial tensile tests of the collagen meshes with three different cross-linking percentages (full-, partial-, and noncross-linked) were carried out along orthogonal directions. Their mechanical properties were studied with the same tests before and after seeding with human derived adipose stem cells (ADSC) after 1 and 7 days. Histological analyses were performed to determine adhesion and proliferation of ADSC. Significant differences in mechanical properties of the unseeded meshes were observed between each orthogonal direction independently of the cross-linking percentage. A better cell adhesion rate was observed in the cross-linked meshes. An increase in the mechanical properties after cell seeding was observed with a direct relation with the degree of cross-linking. All meshes analyzed showed a marked anisotropy that should be taken into account during the surgical procedure. The cross-linking treatment increased cell adhesion and the mechanical properties of the collagen meshes after seeding. These results suggest that the mechanical properties of this type of collagen mesh could be useful as scaffolds for repair of pelvic organ prolapse.
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Affiliation(s)
- Ignacio Ochoa
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN, Spain.
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31
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Martins P, Peña E, Calvo B, Doblaré M, Mascarenhas T, Natal Jorge R, Ferreira A. Prediction of nonlinear elastic behaviour of vaginal tissue: experimental results and model formulation. Comput Methods Biomech Biomed Engin 2010; 13:327-37. [DOI: 10.1080/10255840903208197] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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32
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da Silva-Filho AL, Martins PALS, Parente MP, Saleme CS, Roza T, Pinotti M, Mascarenhas T, Natal Jorge RM. Translation of biomechanics research to urogynecology. Arch Gynecol Obstet 2010; 282:149-55. [DOI: 10.1007/s00404-010-1396-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Accepted: 02/08/2010] [Indexed: 02/03/2023]
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33
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Calvo B, Ramírez A, Alonso A, Grasa J, Soteras F, Osta R, Muñoz M. Passive nonlinear elastic behaviour of skeletal muscle: Experimental results and model formulation. J Biomech 2010; 43:318-25. [DOI: 10.1016/j.jbiomech.2009.08.032] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 07/17/2009] [Accepted: 08/18/2009] [Indexed: 10/20/2022]
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34
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Experimental study and constitutive modeling of the viscoelastic mechanical properties of the human prolapsed vaginal tissue. Biomech Model Mechanobiol 2009; 9:35-44. [DOI: 10.1007/s10237-009-0157-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 04/07/2009] [Indexed: 10/20/2022]
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