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Sharma S, Buist ML. Comparing finite viscoelastic constitutive relations and variational principles in modeling gastrointestinal soft tissue deformation. J Mech Behav Biomed Mater 2024; 155:106560. [PMID: 38744120 DOI: 10.1016/j.jmbbm.2024.106560] [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: 12/18/2023] [Revised: 04/20/2024] [Accepted: 04/23/2024] [Indexed: 05/16/2024]
Abstract
The mechanical attributes of soft tissues within the gastrointestinal (GI) tract are crucial for the effective operation of the GI system, and alterations in these properties may play a role in motility-related disorders. Various constitutive modeling approaches have been suggested to comprehend the response of soft tissues to diverse loading conditions. Among these, hyperelastic constitutive models based on finite elasticity have gained popularity. However, these models fall short in capturing rate- and time-dependent tissue properties. In contrast, finite viscoelastic models offer a solution to overcome these limitations. Nevertheless, the development of a suitable finite viscoelastic model, coupled with a variational formulation for efficient finite element (FE) implementation, remains an ongoing challenge. This study aims to address this gap by developing diverse finite viscoelastic constitutive relations and applying them to characterize soft tissue. Furthermore, the research explores the creation of compressible, nearly incompressible, and incompressible versions of viscoelastic constitutive relations, along with their variational formulation, to facilitate efficient FE implementation. The proposed model demonstrates remarkable accuracy in replicating experimental results, achieving an R2 value exceeding 0.99.
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Affiliation(s)
- Swati Sharma
- Department of Biomedical Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore
| | - Martin Lindsay Buist
- Department of Biomedical Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117583, Singapore.
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2
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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.
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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
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Biomechanics of Hollow Organs: Experimental Testing and Computational Modeling. Bioengineering (Basel) 2023; 10:bioengineering10020175. [PMID: 36829669 PMCID: PMC9952441 DOI: 10.3390/bioengineering10020175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Hollow organs are visceral organs that are hollow tubes or pouches (such as the intestine or the stomach, respectively) or that include a cavity (such as the heart) and which subserve a vital function [...].
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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.
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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
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Zhang S, Xiao J, Wu P, Li C, Chen XD, Deng R, Dai B. A simulation study on expansion of a small intestine model reactor. Chem Eng Res Des 2022. [DOI: 10.1016/j.cherd.2021.12.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Bhattarai A, Kowalczyk W, Tran TN. A literature review on large intestinal hyperelastic constitutive modeling. Clin Biomech (Bristol, Avon) 2021; 88:105445. [PMID: 34416632 DOI: 10.1016/j.clinbiomech.2021.105445] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 06/29/2021] [Accepted: 07/29/2021] [Indexed: 02/07/2023]
Abstract
Impacts, traumas and strokes are spontaneously life-threatening, but chronic symptoms strangle patient every day. Colorectal tissue mechanics in such chronic situations not only regulates the physio-psychological well-being of the patient, but also confirms the level of comfort and post-operative clinical outcomes. Numerous uniaxial and multiaxial tensile experiments on healthy and affected samples have evidenced significant differences in tissue mechanical behavior and strong colorectal anisotropy across each layer in thickness direction and along the length. Furthermore, this study reviewed various forms of passive constitutive models for the highly fibrous colorectal tissue ranging from the simplest linearly elastic and the conventional isotropic hyperelastic to the most sophisticated second harmonic generation image based anisotropic mathematical formulation. Under large deformation, the isotropic description of tissue mechanics is unequivocally ineffective which demands a microstructural based tissue definition. Therefore, the information collected in this review paper would present the current state-of-the-art in colorectal biomechanics and profoundly serve as updated computational resources to develop a sophisticated characterization of colorectal tissues.
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Affiliation(s)
- Aroj Bhattarai
- Department of Orthopaedic Surgery, University of Saarland, Germany
| | | | - Thanh Ngoc Tran
- Department of Orthopaedic Surgery, University of Saarland, Germany.
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Nagaraja S, Leichsenring K, Ambati M, De Lorenzis L, Böl M. On a phase-field approach to model fracture of small intestine walls. Acta Biomater 2021; 130:317-331. [PMID: 34119714 DOI: 10.1016/j.actbio.2021.06.002] [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: 03/02/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 12/15/2022]
Abstract
We address anisotropic elasticity and fracture in small intestine walls (SIWs) with both experimental and computational methods. Uniaxial tension experiments are performed on porcine SIW samples with varying alignments and quantify their nonlinear elastic anisotropic behavior. Fracture experiments on notched SIW strips reveal a high sensitivity of the crack propagation direction and the failure stress on the tissue orientation. From a modeling point of view, the observed anisotropic elastic response is studied with a continuum mechanical model stemming from a strain energy density with a neo-Hookean component and an anisotropic component with four families of fibers. Fracture is addressed with the phase-field approach, featuring two-fold anisotropy in the fracture toughness. Elastic and fracture model parameters are calibrated based on the experimental data, using the maximum and minimum limits of the experimental stress-stretch data set. A very good agreement between experimental data and computational results is obtained, the role of anisotropy being effectively captured by the proposed model in both the elastic and the fracture behavior. STATEMENT OF SIGNIFICANCE: This article reports a comprehensive experimental data set on the mechanical failure behavior of small intestinal tissue, and presents the corresponding protocols for preparing and testing the samples. On the one hand, the results of this study contribute to the understanding of small intestine mechanics and thus to understanding of load transfer mechanisms inside the tissue. On the other hand, these results are used as input for a phase-field modelling approach, presented in this article. The presented model can reproduce the mechanical failure behavior of the small intestine in an excellent way and is thus a promising tool for the future mechanical description of diseased small intestinal tissue.
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Zhao J, Liao D, Wilkens R, Krogh K, Glerup H, Gregersen H. Bowel stiffness associated with histopathologic scoring of stenosis in patients with Crohn's disease. Acta Biomater 2021; 130:332-342. [PMID: 34119715 DOI: 10.1016/j.actbio.2021.06.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/31/2021] [Accepted: 06/03/2021] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND AIMS Intestinal stenosis is a common complication of Crohn's Disease (CD). Stenosis is associated with alteration of bowel mechanical properties. This study aims to quantitate the mechanical properties of the intestinal stenosis and to explore associations between histology and mechanical remodeling at stenotic intestinal sites in CD patients. METHODS Intestinal segments from stenotic sites were studied in vitro from 19 CD patients. A luminal catheter with a bag was used to stepwise pressurize the intestinal segments from 0-100 cmH2O with 10 cmH2O increments. B-mode ultrasound images were obtained at the narrowest part of the stenosis at each pressure level and morphometric parameters were obtained from ultrasound images. The mechanical behavior of the stenotic tissue were characterized by using an isotropic three dimensional strain energy function in Demiray model form, the mechanical constants were obtained by fitting the model to the recorded intraluminal pressure and the inner radius of the stenotic segment of the small bowel. Grading scores were used for histological analysis of inflammation, fibrosis, muscular hypertrophy and adipocyte proliferation in the intestinal layers. The collagen area fraction in intestinal layers was also calculated. Associations between histological and the mechanical constants (stiffness) were analyzed. RESULTS Chronic inflammation was mainly located in mucosa whereas fibrosis was found in submucosa. The mechanical remodeling was performed with changed mechanical constants ranged between 0.35-13.68kPa. The mechanical properties changes were associated mainly with chronic inflammation, fibrosis and combination of inflammation and fibrosis (R>0.69, P<0.001). Furthermore, the mechanical properties correlated with the collagen fraction in submucosa and muscular layers (R>0.53, P<0.05). CONCLUSIONS We quantitated the intestinal stenosis stiffness. Associations were found between bowel mechanical remodeling and histological changes at the stenotic site in CD patients. STATEMENT OF SIGNIFICANCE Although intestinal ultrasonography, CT and MRI can be used to diagnose Crohn's Disease (CD)-associated bowel strictures, these techniques may not have sufficient accuracy and resolution to differentiate predominantly inflammatory strictures from predominantly fibrotic strictures. The present study aims to quantitate the mechanical remodeling of intestinal stenosis and to explore the associations between histological parameters and mechanical properties at the intestinal stenotic sites in CD patients. For the first time, we quantitatively demonstrated that the mechanical properties of the intestinal wall in CD stenosis are associated with the chronic inflammation, fibrosis and collagen fraction in the intestinal layers. The results of this study may facilitate design and development of artificial biomaterials for gastrointestinal organs. The potential clinical implication of this study is that the histological characteristics in patients with CD can be predicted clinically by means of inflammation and fibrosis assessment in conjunction with tissue stiffness measurement.
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Affiliation(s)
- Jingbo Zhao
- Standard (Chongqing) Pathological Diagnosis Center. No. 8 Xiyuan North Road, Shapingba District, Chongqing, China; Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Denmark; Giome Academia, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Donghua Liao
- Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Denmark; Giome Academia, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
| | - Rune Wilkens
- Gastrounit, Division of Medicine, Hvidovre Hospital, University of Copenhagen, Copenhagen, Denmark; Diagnostic Centre, University Research Clinic for Innovative Patient Pathways, Silkeborg Regional Hospital, Silkeborg, Denmark
| | - Klaus Krogh
- Neurogastroenterology Unit, Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Henning Glerup
- Diagnostic Centre, University Research Clinic for Innovative Patient Pathways, Silkeborg Regional Hospital, Silkeborg, Denmark
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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.
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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.
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Biomechanical Force Prediction for Lengthening of Small Intestine during Distraction Enterogenesis. Bioengineering (Basel) 2020; 7:bioengineering7040140. [PMID: 33171760 PMCID: PMC7711478 DOI: 10.3390/bioengineering7040140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/04/2020] [Accepted: 10/28/2020] [Indexed: 11/16/2022] Open
Abstract
Distraction enterogenesis has been extensively studied as a potential treatment for short bowel syndrome, which is the most common form of intestinal failure. Different strategies including parenteral nutrition and surgical lengthening to manage patients with short bowel syndrome are associated with high complication rates. More recently, self-expanding springs have been used to lengthen the small intestine using an intraluminal axial mechanical force, where this biomechanical force stimulates the growth and elongation of the small intestine. Differences in physical characteristics of patients with short bowel syndrome would require a different mechanical force—this is crucial in order to achieve an efficient and safe lengthening outcome. In this study, we aimed to predict the required mechanical force for each potential intestinal size. Based on our previous experimental observations and computational findings, we integrated our experimental measurements of patient biometrics along with mechanical characterization of the soft tissue into our numerical simulations to develop a series of computational models. These computational models can predict the required mechanical force for any potential patient where this can be advantageous in predicting an individual’s tissue response to spring-mediated distraction enterogenesis and can be used toward a safe delivery of the mechanical force.
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ZHANG PEISEN, LI JING, HAO YANG, CIUTI GASTONE, ARAI TATSUO, HUANG QIANG, DARIO PAOLO. EXPERIMENTAL ASSESSMENT OF INTACT COLON DEFORMATION UNDER LOCAL FORCES APPLIED BY MAGNETIC CAPSULE ENDOSCOPES. J MECH MED BIOL 2020. [DOI: 10.1142/s0219519420500414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Magnetically guided capsule endoscopy is a promising technology for clinical application. A platform that simulates the magnetic capsule endoscope system is built to study the deformation process of the colon when its lumen suffers local forces. Force-displacement curves of the porcine large intestine under various experiment conditions, including different loading positions (haustra or taeniae coli), loading directions, colon inner pressures and specimen lengths, were measured to analyze the mechanical behavior of the intact large intestine during interactions with magnetic capsule endoscopes. In the practical application of the magnetic capsule endoscope, these data are imperative to optimize the control scheme and reduce operation risks. Based on our experiments, the taeniae coli of the intact large intestine show higher linear stiffness than the haustra, and inflation reduces the linear stiffness of the colon. Magnetic capsule with small edge radii can more easily damage or even perforate the colon. Based on our test results, we suggest that the force applied to the colon should be limited to below 17[Formula: see text]N when the capsule is actuated forward along the colon and limited to below 10[Formula: see text]N when the capsule is vertical to the colon during lesion screening.
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Affiliation(s)
- PEISEN ZHANG
- Intelligent Robotics Institute, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing, P. R. China
| | - JING LI
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing, P. R. China
| | - YANG HAO
- Intelligent Robotics Institute, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing, P. R. China
| | - GASTONE CIUTI
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing, P. R. China
- The Biorobotics Institute, Scuola Superiore Sant’Anna, 56025, Pontedera, Pisa, Italy
| | - TATSUO ARAI
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing, P. R. China
| | - QIANG HUANG
- Intelligent Robotics Institute, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing, P. R. China
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing, P. R. China
| | - PAOLO DARIO
- Beijing Advanced Innovation Center for Intelligent Robots and Systems, Beijing Institute of Technology, Beijing, P. R. China
- The Biorobotics Institute, Scuola Superiore Sant’Anna, 56025, Pontedera, Pisa, Italy
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Panda SK, Buist ML. A viscoelastic framework for inflation testing of gastrointestinal tissue. J Mech Behav Biomed Mater 2020; 103:103569. [DOI: 10.1016/j.jmbbm.2019.103569] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 11/26/2019] [Accepted: 11/29/2019] [Indexed: 12/01/2022]
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Hosseini HS, Taylor JS, Wood LS, Dunn JC. Biomechanics of small intestine during distraction enterogenesis with an intraluminal spring. J Mech Behav Biomed Mater 2020; 101:103413. [DOI: 10.1016/j.jmbbm.2019.103413] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 06/13/2019] [Accepted: 08/31/2019] [Indexed: 12/25/2022]
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Guachi R, Bini F, Bici M, Campana F, Marinozzi F, Guachi L. Finite element analysis in colorectal surgery: non-linear effects induced by material model and geometry. COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING: IMAGING & VISUALIZATION 2019. [DOI: 10.1080/21681163.2019.1679669] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Robinson Guachi
- Department of Mechatronics, Universidad Internacional del Ecuador, Quito, Ecuador
- Dipartimento di ingegneria Meccanica e Aerospaziale, Universita degli Studi di Roma La Sapienza, Roma, Italy
| | - Fabiano Bini
- Dipartimento di ingegneria Meccanica e Aerospaziale, Universita degli Studi di Roma La Sapienza, Roma, Italy
| | - Michele Bici
- Dipartimento di ingegneria Meccanica e Aerospaziale, Universita degli Studi di Roma La Sapienza, Roma, Italy
| | - Francesca Campana
- Dipartimento di ingegneria Meccanica e Aerospaziale, Universita degli Studi di Roma La Sapienza, Roma, Italy
| | - Franco Marinozzi
- Dipartimento di ingegneria Meccanica e Aerospaziale, Universita degli Studi di Roma La Sapienza, Roma, Italy
| | - Lorena Guachi
- Mathematical and Computational Sciences, Yachay University, Urcuquí, Ecuador
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The Turning Point for Morphomechanical Remodeling During Complete Intestinal Obstruction in Rats Occurs After 12–24 h. Ann Biomed Eng 2018; 46:705-716. [DOI: 10.1007/s10439-018-1992-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 02/05/2018] [Indexed: 12/31/2022]
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Guachi R, Bini F, Bici M, Campana F, Marinozzi F. Finite Element Model Set-up of Colorectal Tissue for Analyzing Surgical Scenarios. VIPIMAGE 2017 2018. [DOI: 10.1007/978-3-319-68195-5_65] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Sokolis DP. Experimental study and biomechanical characterization for the passive small intestine: Identification of regional differences. J Mech Behav Biomed Mater 2017; 74:93-105. [DOI: 10.1016/j.jmbbm.2017.05.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/11/2017] [Accepted: 05/19/2017] [Indexed: 12/16/2022]
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Sun D, Zhao J, Liao D, Chen P, Gregersen H. Shear Modulus of the Partially Obstructed Rat Small Intestine. Ann Biomed Eng 2016; 45:1069-1082. [DOI: 10.1007/s10439-016-1739-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 09/17/2016] [Indexed: 12/11/2022]
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Cao DQ, Luo L, Wang RO, Yang Z, Zhang LL, You LY, Wang Q, Song Q, Li XR, Liang Y. Protective effects of Raphanus sativus extract on intestinal mucosal peroxide damage in rats with incomplete intestinal obstruction. Shijie Huaren Xiaohua Zazhi 2015; 23:4236-4241. [DOI: 10.11569/wcjd.v23.i26.4236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the protective effects of Raphanus sativus extract (Rex) on intestinal mucosal peroxide damage in a rat model of incomplete intestinal obstruction (IIO).
METHODS: Sprague-Dawley rats were randomly divided into a normal group (group A, n = 14), a sham-operation group (group B, n = 14), an intestinal obstruction group (group C, n = 20) and an intestinal obstruction + Rex group (group D, n = 20). IIO was induced by surrounding the terminal ileum with a sterile pipe. After that, the animals in group D was given Rex (100 mg/kg body weight), while the rest groups were given equal volumes of saline. On days 5 and 7, the abdominal cavity was opened to collect 3 mL blood from the abdominal aorta for determining superoxide dismutase (SOD) and malondialdehyde (MDA) levels. Meanwhile, two segments of the small intestine were taken 4 cm above the obstructive for hematoxylin-eosin (HE) staining and for measuring diamine oxidase (DAO), respectively.
RESULTS: At each corresponding time point, compared with group B, SOD and DAO levels were significantly lower (P < 0.05 or P < 0.01) and MDA content and mucosal injury score were significantly higher (P < 0.01) in group C. Swelling, necrosis and shedding were visible in epithelial cells. Meanwhile, the submucosa, muscular and serosa had apparent congestion with infiltration of inflammatory cells. Compared with group C, treatment with Rex in group D significantly increased SOD activity (P < 0.05 or P < 0.01) and DAO content (P < 0.01), while MDA content and mucosal injury score were significantly decreased (P < 0.01). The damage of the ileum mucosa, infiltration of inflammatory cells and vascular responses in the ileum were significantly alleviated after treatment with Rex.
CONCLUSION: Rex can elevate serum SOD activity, reduce MDA content and increase tissue DAO levels in rats with IIO to protect the intestinal mucosal from being damaged by oxidative stress reaction effectively.
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Robertson D, Cook D. Unrealistic statistics: how average constitutive coefficients can produce non-physical results. J Mech Behav Biomed Mater 2014; 40:234-239. [PMID: 25247769 DOI: 10.1016/j.jmbbm.2014.09.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 08/24/2014] [Accepted: 09/02/2014] [Indexed: 12/12/2022]
Abstract
The coefficients of constitutive models are frequently averaged in order to concisely summarize the complex, nonlinear, material properties of biomedical materials. However, when dealing with nonlinear systems, average inputs (e.g. average constitutive coefficients) often fail to generate average behavior. This raises an important issue because average nonlinear constitutive coefficients of biomedical materials are commonly reported in the literature. This paper provides examples which demonstrate that average constitutive coefficients applied to nonlinear constitutive laws in the field of biomedical material characterization can fail to produce average stress-strain responses and in some cases produce non-physical responses. Results are presented from a literature survey which indicates that approximately 90% of tissue measurement studies that employ a nonlinear constitutive model report average nonlinear constitutive coefficients. We suggest that reviewers and editors of future measurement studies discourage the reporting of average nonlinear constitutive coefficients. Reporting of individual coefficient sets for each test sample should be considered and discussed as designation for a "best practice" in the field of biomedical material characterization.
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Affiliation(s)
- Daniel Robertson
- Department of Mechanical Engineering, New York University-Abu Dhabi, PO BOX 129188, Abu Dhabi, United Arab Emirates.
| | - Douglas Cook
- Department of Mechanical Engineering, New York University-Abu Dhabi, PO BOX 129188, Abu Dhabi, United Arab Emirates.
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Identification of biomechanical properties in vivo in human uterine cervix. J Mech Behav Biomed Mater 2014; 39:27-37. [PMID: 25084120 DOI: 10.1016/j.jmbbm.2014.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 06/30/2014] [Accepted: 07/04/2014] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND AIMS The course and outcome of pregnancy is closely correlated to change of biomechanical properties of the uterine cervix. The aim of this study was to build a non-linear, fiber reinforced mechanical model of the cervix for estimation of mechanical characteristics of the cervix in early- and term-pregnant women based on recordings of in vivo pressure and diameter by means of the Functional Luminal Imaging Probe (FLIP) technology. MATERIALS AND METHODS Five early- and six term-pregnant women were examined with a FLIP probe. The bag on the probe was inserted into the cervical canal for concomitant measurement of diameters at 16 serial locations along the canal and the bag pressure. The bag was inflated to a maximum volume of 50 ml. A three-fiber-families model including isotropic elastin-dominated matrix and anisotropic collagen was introduced to describe the mechanical behavior of the cervical canal. The unknown geometric and mechanical parameters were calculated on the basis of the mid-cervical diameters and the intraluminal pressures during the inflation. RESULTS The wall thickness in the unloaded state (zero pressure applied) and mechanical properties of the matrix material (c) and collagens (c1, c2) were estimated with good fits of the calculated intraluminal pressures to the FLIP recordings during the cervical canal distension. No significant difference in the wall thickness was found between the early- and term-pregnant women (10.3 ± 0.8mm vs. 11.7 ± 2.2mm, p=0.30). The cervical matrix material and the collagen in the early-pregnant women were much stiffer than that in the term-pregnant women (p<0.05). CONCLUSIONS The cervical mechanical properties can be obtained from recorded pressure and diameter data in vivo via the established mechanical model. Matrix material and collagens of the cervix wall were remodeled during pregnancy. The mechanical model can be applied to other tubular visceral organs where concomitant measures of pressure and diameter can be obtained for better understanding diseases and their evolution or treatment.
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Suki B. Assessing the Functional Mechanical Properties of Bioengineered Organs With Emphasis on the Lung. J Cell Physiol 2014; 229:1134-40. [DOI: 10.1002/jcp.24600] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 03/03/2014] [Indexed: 01/16/2023]
Affiliation(s)
- Béla Suki
- Department of Biomedical Engineering; Boston University; Boston Massachusetts
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Sokolis DP, Sassani SG. Microstructure-based constitutive modeling for the large intestine validated by histological observations. J Mech Behav Biomed Mater 2013; 21:149-66. [DOI: 10.1016/j.jmbbm.2013.02.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 02/12/2013] [Accepted: 02/20/2013] [Indexed: 10/27/2022]
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Finite element modelling of stapled colorectal end-to-end anastomosis: Advantages of variable height stapler design. J Biomech 2012; 45:2693-7. [DOI: 10.1016/j.jbiomech.2012.07.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 07/12/2012] [Accepted: 07/14/2012] [Indexed: 01/14/2023]
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Sokolis DP, Orfanidis IK, Peroulis M. Biomechanical testing and material characterization for the rat large intestine: regional dependence of material parameters. Physiol Meas 2011; 32:1969-82. [DOI: 10.1088/0967-3334/32/12/007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Bellini C, Glass P, Sitti M, Di Martino ES. Biaxial mechanical modeling of the small intestine. J Mech Behav Biomed Mater 2011; 4:1727-40. [DOI: 10.1016/j.jmbbm.2011.05.030] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Revised: 05/03/2011] [Accepted: 05/23/2011] [Indexed: 12/22/2022]
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Yang Z, Li K, Yuan ML, Wang C, Bo L, Qiu YB, Peng MF, Zhu XY, Zhang L. Effect of electroacupuncture at Tsusanli on intestinal myoelectric activity in rats with incomplete intestinal obstruction. Shijie Huaren Xiaohua Zazhi 2011; 19:1237-1243. [DOI: 10.11569/wcjd.v19.i12.1237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effect of electroacupuncture at Tsusanli on the regulation of gastrointestinal motility in rats with incomplete intestinal obstruction.
METHODS: The 1/2 terminal ileum of rats with intestinal obstruction was ligated to generate a model of incomplete intestinal obstruction. Rats were randomly divided into control group (n = 10), sham-operated group (n = 10), intestinal obstruction group (IO group, n = 10), and intestinal obstruction + electroacupuncture group (14 d IO + EA subgroup, n = 10, 21 d IO + EA subgroup, n = 10). At 2 hours after the last treatment, changes in body weight and myoelectric slow wave activity in the ileum were recorded, and ileal histomorphological changes were observed with the unaided eyes.
RESULTS: Compared to the control group, rats of the IO group showed significant weight loss (P < 0.01). However, the body weight increased obviously in the IO+EA group compared to the IO group (P < 0.01). The amplitude (mV) for the myoelectric slow wave in the IO group on day 14 was significantly lower than that in the control group (0.11 ± 0.03 vs 0.35 ± 0.06, P < 0.01), and the coefficient of variation (CV) of the mean frequency (%) and amplitude (%) was significantly higher in the IO group than in the control and sham-operated groups (27.71 ± 10.54 vs 14.08 ± 4.22, 22.00 ± 6.24; 75.54 ± 8.59 vs 15.84 ± 1.49, 20.67 ± 7.57, all P < 0.01). After 14 days of electroacupuncture, the mean frequency for the myoelectric slow wave in the ileum in the IO + EA group was significantly higher than that in the IO group (33.18 ± 2.56 vs 24.01 ± 0.92, P < 0.01). Compared to the IO group, the mean amplitude (mV) in the IO + EA group remarkably increased on day 5 (0.25 ± 0.09 vs 0.11 ± 0.03, P < 0.05). The CV of frequency (%) in the IO + EA group was significantly lower than that in the IO group (17.02 ± 3.62 vs 27.71 ± 10.54, P < 0.05). The CV of amplitude (%) in the IO + EA group was significantly lower than that in the IO group (58.39 ± 9.56 vs 75.54 ± 8.59, P < 0.01). After 21 days of electroacupuncture, the mean frequency in the ileum in the IO + EA group significantly increased compared to the IO group (40.55 ± 5.29 vs 33.18 ± 2.56, P < 0.01). Compared to the IO group, the CV of amplitude (%) in the IO + EA group was significantly lower (44.00 ± 11.61 vs 58.39 ± 9.56, P < 0.05).
CONCLUSION: A rat model of incomplete intestinal obstruction could be generated by ligating the 1/2 terminal ileum of rats with intestinal obstruction. Electroacupuncture at Tsusanli exerts a therapeutic effect against incomplete intestinal obstruction by regulating intestinal myoelectric activity.
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