1
|
Durcan C, Hossain M, Chagnon G, Perić D, Girard E. Characterization of the layer, direction and time-dependent mechanical behaviour of the human oesophagus and the effects of formalin preservation. J R Soc Interface 2024; 21:20230592. [PMID: 38593841 PMCID: PMC11003784 DOI: 10.1098/rsif.2023.0592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 03/05/2024] [Indexed: 04/11/2024] Open
Abstract
The mechanical characterization of the oesophagus is essential for applications such as medical device design, surgical simulations and tissue engineering, as well as for investigating the organ's pathophysiology. However, the material response of the oesophagus has not been established ex vivo in regard to the more complex aspects of its mechanical behaviour using fresh, human tissue: as of yet, in the literature, only the hyperelastic response of the intact wall has been studied. Therefore, in this study, the layer-dependent, anisotropic, visco-hyperelastic behaviour of the human oesophagus was investigated through various mechanical tests. For this, cyclic tests, with increasing stretch levels, were conducted on the layers of the human oesophagus in the longitudinal and circumferential directions and at two different strain rates. Additionally, stress-relaxation tests on the oesophageal layers were carried out in both directions. Overall, the results show discrete properties in each layer and direction, highlighting the importance of treating the oesophagus as a multi-layered composite material with direction-dependent behaviour. Previously, the authors conducted layer-dependent cyclic experimentation on formalin-embalmed human oesophagi. A comparison between the fresh and embalmed tissue response was carried out and revealed surprising similarities in terms of anisotropy, strain-rate dependency, stress-softening and hysteresis, with the main difference between the two preservation states being the magnitude of these properties. As formalin fixation is known to notably affect the formation of cross-links between the collagen of biological materials, the differences may reveal the influence of cross-links on the mechanical behaviour of soft tissues.
Collapse
Affiliation(s)
- Ciara Durcan
- Zienkiewicz Institute for Modelling, Data and Artificial Intelligence, Faculty of Science and Engineering, Swansea University, Swansea SA1 8EN, UK
- CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble Alpes University, Grenoble 38000, France
| | - Mokarram Hossain
- Zienkiewicz Institute for Modelling, Data and Artificial Intelligence, Faculty of Science and Engineering, Swansea University, Swansea SA1 8EN, UK
| | - Grégory Chagnon
- CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble Alpes University, Grenoble 38000, France
| | - Djordje Perić
- Zienkiewicz Institute for Modelling, Data and Artificial Intelligence, Faculty of Science and Engineering, Swansea University, Swansea SA1 8EN, UK
| | - Edouard Girard
- CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, Grenoble Alpes University, Grenoble 38000, France
- Laboratoire d’Anatomie des Alpes Françaises, Grenoble Alpes University, Grenoble, France
| |
Collapse
|
2
|
Gheysen L, Maes L, Caenen A, Segers P, Peirlinck M, Famaey N. Uncertainty quantification of the wall thickness and stiffness in an idealized dissected aorta. J Mech Behav Biomed Mater 2024; 151:106370. [PMID: 38224645 DOI: 10.1016/j.jmbbm.2024.106370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 12/21/2023] [Accepted: 01/01/2024] [Indexed: 01/17/2024]
Abstract
Personalized treatment informed by computational models has the potential to markedly improve the outcome for patients with a type B aortic dissection. However, existing computational models of dissected walls significantly simplify the characteristic false lumen, tears and/or material behavior. Moreover, the patient-specific wall thickness and stiffness cannot be accurately captured non-invasively in clinical practice, which inevitably leads to assumptions in these wall models. It is important to evaluate the impact of the corresponding uncertainty on the predicted wall deformations and stress, which are both key outcome indicators for treatment optimization. Therefore, a physiology-inspired finite element framework was proposed to model the wall deformation and stress of a type B aortic dissection at diastolic and systolic pressure. Based on this framework, 300 finite element analyses, sampled with a Latin hypercube, were performed to assess the global uncertainty, introduced by 4 uncertain wall thickness and stiffness input parameters, on 4 displacement and stress output parameters. The specific impact of each input parameter was estimated using Gaussian process regression, as surrogate model of the finite element framework, and a δ moment-independent analysis. The global uncertainty analysis indicated minor differences between the uncertainty at diastolic and systolic pressure. For all output parameters, the 4th quartile contained the major fraction of the uncertainty. The parameter-specific uncertainty analysis elucidated that the material stiffness and relative thickness of the dissected membrane were the respective main determinants of the wall deformation and stress. The uncertainty analysis provides insight into the effect of uncertain wall thickness and stiffness parameters on the predicted deformation and stress. Moreover, it emphasizes the need for probabilistic rather than deterministic predictions for clinical decision making in aortic dissections.
Collapse
Affiliation(s)
- Lise Gheysen
- Institute for Biomedical Engineering and Technology, Electronics and Information Systems, Ghent University, Belgium.
| | - Lauranne Maes
- Biomechanics Section, Mechanical Engineering, KU Leuven, Belgium
| | - Annette Caenen
- Institute for Biomedical Engineering and Technology, Electronics and Information Systems, Ghent University, Belgium; Cardiovascular Imaging and Dynamics, Department of Cardiovascular Sciences, KU Leuven, Belgium
| | - Patrick Segers
- Institute for Biomedical Engineering and Technology, Electronics and Information Systems, Ghent University, Belgium
| | - Mathias Peirlinck
- Department of BioMechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, the Netherlands
| | - Nele Famaey
- Biomechanics Section, Mechanical Engineering, KU Leuven, Belgium
| |
Collapse
|
3
|
Durcan C, Hossain M, Chagnon G, Perić D, Girard E. Mechanical experimentation of the gastrointestinal tract: a systematic review. Biomech Model Mechanobiol 2024; 23:23-59. [PMID: 37935880 PMCID: PMC10901955 DOI: 10.1007/s10237-023-01773-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 09/10/2023] [Indexed: 11/09/2023]
Abstract
The gastrointestinal (GI) organs of the human body are responsible for transporting and extracting nutrients from food and drink, as well as excreting solid waste. Biomechanical experimentation of the GI organs provides insight into the mechanisms involved in their normal physiological functions, as well as understanding of how diseases can cause disruption to these. Additionally, experimental findings form the basis of all finite element (FE) modelling of these organs, which have a wide array of applications within medicine and engineering. This systematic review summarises the experimental studies that are currently in the literature (n = 247) and outlines the areas in which experimentation is lacking, highlighting what is still required in order to more fully understand the mechanical behaviour of the GI organs. These include (i) more human data, allowing for more accurate modelling for applications within medicine, (ii) an increase in time-dependent studies, and (iii) more sophisticated in vivo testing methods which allow for both the layer- and direction-dependent characterisation of the GI organs. The findings of this review can also be used to identify experimental data for the readers' own constitutive or FE modelling as the experimental studies have been grouped in terms of organ (oesophagus, stomach, small intestine, large intestine or rectum), test condition (ex vivo or in vivo), number of directions studied (isotropic or anisotropic), species family (human, porcine, feline etc.), tissue condition (intact wall or layer-dependent) and the type of test performed (biaxial tension, inflation-extension, distension (pressure-diameter), etc.). Furthermore, the studies that investigated the time-dependent (viscoelastic) behaviour of the tissues have been presented.
Collapse
Affiliation(s)
- Ciara Durcan
- Zienkiewicz Centre for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Mokarram Hossain
- Zienkiewicz Centre for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK.
| | - Grégory Chagnon
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Djordje Perić
- Zienkiewicz Centre for Modelling, Data and AI, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK
| | - Edouard Girard
- Université Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
- Laboratoire d'Anatomie des Alpes Françaises, Université Grenoble Alpes, Grenoble, France
| |
Collapse
|
4
|
Caulk AW, Chatterjee M, Barr SJ, Contini EM. Mechanobiological considerations in colorectal stapling: Implications for technology development. Surg Open Sci 2023; 13:54-65. [PMID: 37159635 PMCID: PMC10163679 DOI: 10.1016/j.sopen.2023.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/07/2023] [Accepted: 04/08/2023] [Indexed: 05/11/2023] Open
Abstract
Technological advancements in minimally invasive surgery have led to significant improvements in patient outcomes. One such technology is surgical stapling, which has evolved into a key component of many operating rooms by facilitating ease and efficacy in resection and repair of diseased or otherwise compromised tissue. Despite such advancements, adverse post-operative outcomes such as anastomotic leak remain a persistent problem in surgical stapling and its correlates (i.e., hand-sewing), most notably in low colorectal or coloanal procedures. Many factors may drive anastomotic leaks, including tissue perfusion, microbiome composition, and patient factors such as pre-existing disease. Surgical intervention induces complex acute and chronic changes to the mechanical environment of the tissue; however, roles of mechanical forces in post-operative healing remain poorly characterized. It is well known that cells sense and respond to their local mechanical environment and that dysfunction of this "mechanosensing" phenomenon contributes to a myriad of diseases. Mechanosensing has been investigated in wound healing contexts such as dermal incisional and excisional wounds and development of pressure ulcers; however, reports investigating roles of mechanical forces in adverse post-operative gastrointestinal wound healing are lacking. To understand this relationship well, it is critical to understand: 1) the intraoperative material responses of tissue to surgical intervention, and 2) the post-operative mechanobiological response of the tissue to surgically imposed forces. In this review, we summarize the state of the field in each of these contexts while highlighting areas of opportunity for discovery and innovation which can positively impact patient outcomes in minimally invasive surgery.
Collapse
Affiliation(s)
- Alexander W. Caulk
- Corresponding author at: 60 Middletown Ave., North Haven, CT 06473, USA.
| | | | | | | |
Collapse
|
5
|
Ramaraju H, Sferra SR, Kunisaki SM, Hollister SJ. Finite element analysis of esophageal atresia repair with biodegradable polymer sleeves. J Mech Behav Biomed Mater 2022; 133:105349. [DOI: 10.1016/j.jmbbm.2022.105349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/20/2022] [Accepted: 06/28/2022] [Indexed: 10/17/2022]
|
6
|
Patel B, Gizzi A, Hashemi J, Awakeem Y, Gregersen H, Kassab G. Biomechanical constitutive modeling of the gastrointestinal tissues: a systematic review. MATERIALS & DESIGN 2022; 217:110576. [PMID: 35935127 PMCID: PMC9351365 DOI: 10.1016/j.matdes.2022.110576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The gastrointestinal (GI) tract is a continuous channel through the body that consists of the esophagus, the stomach, the small intestine, the large intestine, and the rectum. Its primary functions are to move the intake of food for digestion before storing and ultimately expulsion of feces. The mechanical behavior of GI tissues thus plays a crucial role for GI function in health and disease. The mechanical properties are characterized by a biomechanical constitutive model, which is a mathematical representation of the relation between load and deformation in a tissue. Hence, validated biomechanical constitutive models are essential to characterize and simulate the mechanical behavior of the GI tract. Here, a systematic review of these constitutive models is provided. This review is limited to studies where a model of the strain energy function is proposed to characterize the stress-strain relation of a GI tissue. Several needs are identified for more advanced modeling including: 1) Microstructural models that provide actual structure-function relations; 2) Validation of coupled electro-mechanical models accounting for active muscle contractions; 3) Human data to develop and validate models. The findings from this review provide guidelines for using existing constitutive models as well as perspective and directions for future studies.
Collapse
Affiliation(s)
- Bhavesh Patel
- California Medical Innovations Institute, 11107 Roselle St, San Diego, CA 92121, USA
| | - Alessio Gizzi
- Department of Engineering, Campus Bio-Medico University of Rome, Via A. del Portillo 21, 00128 Rome, IT
| | - Javad Hashemi
- California Medical Innovations Institute, 11107 Roselle St, San Diego, CA 92121, USA
| | - Yousif Awakeem
- California Medical Innovations Institute, 11107 Roselle St, San Diego, CA 92121, USA
| | - Hans Gregersen
- California Medical Innovations Institute, 11107 Roselle St, San Diego, CA 92121, USA
| | - Ghassan Kassab
- California Medical Innovations Institute, 11107 Roselle St, San Diego, CA 92121, USA
- Corresponding author , Tel: 001-858-249-7400, Fax: 001-858-249-7419, (Ghassan Kassab)
| |
Collapse
|
7
|
Durcan C, Hossain M, Chagnon G, Perić D, Bsiesy L, Karam G, Girard E. Experimental investigations of the human oesophagus: anisotropic properties of the embalmed muscular layer under large deformation. Biomech Model Mechanobiol 2022; 21:1169-1186. [PMID: 35477829 PMCID: PMC9045687 DOI: 10.1007/s10237-022-01583-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 03/31/2022] [Indexed: 11/24/2022]
Abstract
The oesophagus is a primarily mechanical organ whose material characterisation would aid in the investigation of its pathophysiology, help in the field of tissue engineering, and improve surgical simulations and the design of medical devices. However, the layer-dependent, anisotropic properties of the organ have not been investigated using human tissue, particularly in regard to its viscoelastic and stress-softening behaviour. Restrictions caused by the COVID-19 pandemic meant that fresh human tissue was not available for dissection. Therefore, in this study, the layer-specific material properties of the human oesophagus were investigated through ex vivo experimentation of the embalmed muscularis propria layer. For this, a series of uniaxial tension cyclic tests with increasing stretch levels were conducted at two different strain rates. The muscular layers from three different cadaveric specimens were tested in both the longitudinal and circumferential directions. The results displayed highly nonlinear and anisotropic behaviour, with both time- and history-dependent stress-softening. The longitudinal direction was found to be stiffer than the circumferential direction at both strain rates. Strain rate-dependent behaviour was apparent, with an increase in strain rate resulting in an increase in stiffness in both directions. Histological analysis was carried out via various staining methods; the results of which were discussed with regard to the experimentally observed stress-stretch response. Finally, the behaviour of the muscularis propria was simulated using a matrix-fibre model able to capture the various mechanical phenomena exhibited, the fibre orientation of which was driven by the histological findings of the study.
Collapse
Affiliation(s)
- Ciara Durcan
- Zienkiewicz Centre for Computational Engineering, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK.,Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Mokarram Hossain
- Zienkiewicz Centre for Computational Engineering, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK.
| | - Grégory Chagnon
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Djordje Perić
- Zienkiewicz Centre for Computational Engineering, Faculty of Science and Engineering, Swansea University, Swansea, SA1 8EN, UK
| | - Lara Bsiesy
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Georges Karam
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Edouard Girard
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France.,Laboratoire d'Anatomie des Alpes Françaises, Univ. Grenoble Alpes, Grenoble, France
| |
Collapse
|
8
|
Acharya S, Halder S, Kou W, Kahrilas PJ, Pandolfino JE, Patankar NA. A fully resolved multiphysics model of gastric peristalsis and bolus emptying in the upper gastrointestinal tract. Comput Biol Med 2022; 143:104948. [PMID: 35091365 PMCID: PMC9014465 DOI: 10.1016/j.compbiomed.2021.104948] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/09/2021] [Accepted: 10/13/2021] [Indexed: 11/22/2022]
Abstract
Over the past few decades, in silico modeling of organ systems has significantly furthered our understanding of their physiology and biomechanical function. In spite of the relative importance of the digestive system in normal functioning of the human body, there is a scarcity of high-fidelity models for the upper gastrointestinal tract including the esophagus and the stomach. In this work, we present a detailed numerical model of the upper gastrointestinal tract that not only accounts for the fiber architecture of the muscle walls, but also the multiphasic components they help transport during normal digestive function. Construction details for 3D models of representative stomach geometry are presented along with a simple strategy for assigning circular and longitudinal muscle fiber orientations for each layer. We developed a fully resolved model of the stomach to simulate gastric peristalsis by systematically activating muscle fibers embedded in the stomach. Following this, for the first time, we simulate gravity-driven bolus emptying into the stomach due to density differences between ingested contents and fluid contents of the stomach. Finally, we present a case of retrograde flow of fluid from the stomach into the esophagus, resembling the phenomenon of acid reflux. This detailed computational model of the upper gastrointestinal tract provides a foundation for future models to investigate the biomechanics of acid reflux and probe various strategies for gastric bypass surgeries to address the growing problem of obesity.
Collapse
Affiliation(s)
- Shashank Acharya
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Sourav Halder
- Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL, 60208, USA
| | - Wenjun Kou
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Peter J Kahrilas
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - John E Pandolfino
- Division of Gastroenterology and Hepatology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA
| | - Neelesh A Patankar
- Department of Mechanical Engineering, Northwestern University, Evanston, IL, 60208, USA; Theoretical and Applied Mechanics Program, Northwestern University, Evanston, IL, 60208, USA.
| |
Collapse
|
9
|
Xu R, Fang X, Wu S, Wang Y, Zhong Y, Hou R, Zhang L, Shao L, Pang Q, Zhang J, Cui X, Zuo R, Yao L, Zhu Y. Development and Prospect of Esophageal Tissue Engineering. Front Bioeng Biotechnol 2022; 10:853193. [PMID: 35252159 PMCID: PMC8892191 DOI: 10.3389/fbioe.2022.853193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Currently, patients with esophageal cancer, especially advanced patients, usually use autologous tissue for esophageal alternative therapy. However, an alternative therapy is often accompanied by serious complications such as ischemia and leakage, which seriously affect the prognosis of patients. Tissue engineering has been widely studied as one of the ideal methods for the treatment of esophageal cancer. In view of the complex multi-layer structure of the natural esophagus, how to use the tissue engineering method to design the scaffold with structure and function matching with the natural tissue is the principle that the tissue engineering method must follow. This article will analyze and summarize the construction methods, with or without cells, and repair effects of single-layer scaffold and multi-layer scaffold. Especially in the repair of full-thickness and circumferential esophageal defects, the flexible design method and the binding force between the layers of the scaffold are very important. In short, esophageal tissue engineering technology has broad prospects and plays a more and more important role in the treatment of esophageal diseases.
Collapse
Affiliation(s)
- Rui Xu
- The Affiliated Hospital of Medical School, Ningbo University, Ningbo, China
- School of Medicine, Ningbo University, Ningbo, China
| | - Xinnan Fang
- School of Medicine, Ningbo University, Ningbo, China
| | - Shengqian Wu
- School of Medicine, Ningbo University, Ningbo, China
| | - Yiyin Wang
- School of Medicine, Ningbo University, Ningbo, China
| | - Yi Zhong
- School of Medicine, Ningbo University, Ningbo, China
| | - Ruixia Hou
- The Affiliated Hospital of Medical School, Ningbo University, Ningbo, China
- School of Medicine, Ningbo University, Ningbo, China
- *Correspondence: Ruixia Hou,
| | - Libing Zhang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, China
| | - Lei Shao
- School of Medicine, Ningbo University, Ningbo, China
| | - Qian Pang
- School of Medicine, Ningbo University, Ningbo, China
| | - Jian Zhang
- The Affiliated Lihuili Hospital, Ningbo University, Ningbo, China
| | - Xiang Cui
- The Affiliated Lihuili Hospital, Ningbo University, Ningbo, China
| | - Rongyue Zuo
- The Affiliated Hospital of Medical School, Ningbo University, Ningbo, China
| | - Liwei Yao
- The Affiliated Hospital of Medical School, Ningbo University, Ningbo, China
| | - Yabin Zhu
- School of Medicine, Ningbo University, Ningbo, China
| |
Collapse
|
10
|
Ren P, Deng X, Li K, Li G, Li W. 3D biomechanical properties of the layered esophagus: Fung-type SEF and new constitutive model. Biomech Model Mechanobiol 2021; 20:1775-1788. [PMID: 34132899 DOI: 10.1007/s10237-021-01476-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 06/04/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND PURPOSE Most current studies on the passive biomechanical properties of esophageal tissues directly use the exponential strain energy function (SEF) to fit and calculate the constants of the constitutive equation. In the context of the extensive application of exponential SEF, in-depth research on the exponential SEF is still lacking. The purpose of this study is to combine the exponential function with the polynomial SEF to obtain the most suitable constitutive equation to describe the three-dimensional passive behavior of the esophagus. METHODS fresh pig esophagus with a length of 13 cm in the middle position was selected as esophageal samples. The esophageal sample was separated into muscular layer and mucosal layer with surgical scissors. Stretch-inflation mechanical tests of the intact esophagus, esophageal muscular, and esophageal mucosa were carried out on a triaxial test machine. The external radius, axial force, and internal pressure were recorded simultaneously. The seven-parameter Fung-type SEF and several new SEFs combining polynomials and exponents were used to fit the experimental data curves. RESULTS The stretch-inflation test data and the morphometric parameters at the zero-stress state of the layered esophagus were obtained. The new SEF with polynomial and exponential combination is more suitable to describe describing the three-dimensional passive biomechanical properties of esophageal tissue. Among them, New-Fung13 SEF is more suitable for describing the passive biomechanical properties of intact esophageal tissue, Sokolis-Fung13 SEF is more suitable for the esophageal muscle layer, and New-Fung10 SEF is more suitable for the esophageal mucosa. The constitutive parameters of the optimal constitutive model for each layer of the esophagus were obtained.
Collapse
Affiliation(s)
- Pan Ren
- Tribology Research Institute, Key Laboratory for Advanced Technology of Materials of Ministry of Education, Southwest Jiaotong University, Chengdu, 610031, China
| | - Xing Deng
- Tribology Research Institute, Key Laboratory for Advanced Technology of Materials of Ministry of Education, Southwest Jiaotong University, Chengdu, 610031, China
| | - KeZhou Li
- Department of Pancreatic Surgery, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - GuiHao Li
- Tribology Research Institute, Key Laboratory for Advanced Technology of Materials of Ministry of Education, Southwest Jiaotong University, Chengdu, 610031, China
| | - Wei Li
- Tribology Research Institute, Key Laboratory for Advanced Technology of Materials of Ministry of Education, Southwest Jiaotong University, Chengdu, 610031, China.
| |
Collapse
|
11
|
Wang Y, Song XF, Su YS, Xu XS. Design and evaluation of a novel anti-reflux biliary stent with cone spiral valve. Proc Inst Mech Eng H 2020; 235:54-64. [PMID: 32988290 DOI: 10.1177/0954411920959986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Endoscopic placement of biliary stent is a well-established palliative treatment for biliary obstruction. However, duodenobiliary reflux after stent placement has been a common problem which may lead to dreadful complications. This paper designed a novel anti-reflux biliary stent with a cone spiral valve. Fluid-Structure Interaction (FSI) simulations were established to evaluate the efficiency of the anti-reflux stent comparing with a clinically applied standard stent. According to the stress distribution of the valve, the fatigue performance in the stress concentration area was analyzed. The results show that when the antegrade flow through the valve, the cone spiral valve could stretch and open to realize adequate drainage under the normal physiological pressure of biliary tract; When the duodenal reflux through the valve, the valve would be compressed and close with a result of nearly zero at the outlet flow rate. Furthermore, the anti-reflux stent achieved improved radial mechanical performance with 2.7 times higher radial stiffness than standard stent. Finite element analysis (FEA) also indicates that compared with the standard stent, the addition of the anti-reflux valve had little negative effect on flexibility of the stent. Fatigue analysis results showed that the valve was reliable. This research provides the new stent with a cone spiral valve and proves that it is technically feasible and effective for preventing the duodenobiliary reflux while ensuring the antegrade bile flow without compromising the other biomechanical performances.
Collapse
Affiliation(s)
- Yue Wang
- Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin, China
| | - Xiao-Fei Song
- Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin, China
| | - Yu-Shan Su
- Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin, China
| | - Xin-Sheng Xu
- Nankai Hospital, Nankai University, Tianjin, China
| |
Collapse
|
12
|
Zaccaria A, Migliavacca F, Pennati G, Petrini L. Modeling of braided stents: Comparison of geometry reconstruction and contact strategies. J Biomech 2020; 107:109841. [DOI: 10.1016/j.jbiomech.2020.109841] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 04/21/2020] [Accepted: 05/05/2020] [Indexed: 11/25/2022]
|
13
|
Del Rosso S, Iannucci L, Curtis PT. Finite element simulation of the braiding process. ACTA ACUST UNITED AC 2019; 5:1. [PMID: 30873338 PMCID: PMC6383729 DOI: 10.1186/s40759-019-0041-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 01/09/2019] [Indexed: 11/10/2022]
Abstract
Braiding is one of the most common technique employed for the manufacture of fabrics and ropes. It is also commonly used to produce near-net shaped preforms for advanced fibre reinforced composites. This paper presents an explicit finite element approach to create and simulate the braiding process for the virtual manufacture of 2D braids. The process starts from the definition of an analytical function which describes the movement of the carriers on a braiding track plate. Models of idealised Maypole-type braiding machines are built and used to shape virtual yarns into braids. This procedure can be used in a parameter control fashion, to optimise or to create virtual braided structures, which can serve as input for other structural analyses. It is emphasised that multiple cylinders are required for the modelling of a multifilament yarn to achieve better correlation with the experimental results. A parametric study is presented to investigate the effect of the number of virtual cylinders to represent a real yarn and the shape of the final braid. Excellent correlation was found between the virtual models and the experimental results when comparing the braid angle and yarn width.
Collapse
Affiliation(s)
- S Del Rosso
- Imperial College London, Exhibition Road, London, SW7 2AZ UK
| | - L Iannucci
- Imperial College London, Exhibition Road, London, SW7 2AZ UK
| | - P T Curtis
- Imperial College London, Exhibition Road, London, SW7 2AZ UK
| |
Collapse
|
14
|
A modular inverse elastostatics approach to resolve the pressure-induced stress state for in vivo imaging based cardiovascular modeling. J Mech Behav Biomed Mater 2018; 85:124-133. [DOI: 10.1016/j.jmbbm.2018.05.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/28/2018] [Accepted: 05/22/2018] [Indexed: 01/18/2023]
|
15
|
Mozafari H, Dong P, Zhao S, Bi Y, Han X, Gu L. Migration resistance of esophageal stents: The role of stent design. Comput Biol Med 2018; 100:43-49. [PMID: 29975854 DOI: 10.1016/j.compbiomed.2018.06.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 06/26/2018] [Accepted: 06/26/2018] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Stenting is one of the major treatments for malignant esophageal cancer. However, stent migration compromises clinical outcomes. A flared end design of the stent diminishes its migration. The goal of this work is to quantitatively characterize stent migration to develop new strategies for better clinical outcomes. METHODS An esophageal stent with flared ends and a straight counterpart were virtually deployed in an esophagus with asymmetric stricture using the finite element method. The resulted esophagus shape, wall stress, and migration resistance force of the stent were quantified and compared. RESULTS The lumen gain for both the flared stent and the straight one exhibited no significant difference. The flared stent induced a significantly larger contact force and thus a larger stress onto the esophagus wall. In addition, more migration resistance force was required to pull the flared stent through the esophagus. This force was inversely related to the occurrence rate of stent migration. A doubled strut diameter also increased the migration resistance force by approximately 56%. An increased friction coefficient from 0.1 to 0.3 also boosted the migration resistance force by approximately 39%. SUMMARY The mechanical advantage of the flared stent was unveiled by the significantly increased contact force, which provided the anchoring effect to resist stent migration. Both the strut diameter and friction coefficient positively correlated with the migration resistance force, and thus the occurrence of stent migration.
Collapse
Affiliation(s)
- Hozhabr Mozafari
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588-0656, USA
| | - Pengfei Dong
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588-0656, USA
| | - Shijia Zhao
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588-0656, USA
| | - Yonghua Bi
- Department of Interventional Radiology, The First Affiliated Hospital of Zhengzhou University, Henan Province, China
| | - Xinwei Han
- Department of Interventional Radiology, The First Affiliated Hospital of Zhengzhou University, Henan Province, China.
| | - Linxia Gu
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68588-0656, USA; Department of Interventional Radiology, The First Affiliated Hospital of Zhengzhou University, Henan Province, China; Nebraska Center for Materials and Nanoscience, Lincoln, NE, 68588-0656, USA.
| |
Collapse
|