1
|
Tatarenko Y, Li M, Pouletaut P, Kammoun M, Hawse JR, Joumaa V, Herzog W, Chatelin S, Bensamoun SF. Multiscale analysis of Klf10's impact on the passive mechanical properties of murine skeletal muscle. J Mech Behav Biomed Mater 2024; 150:106298. [PMID: 38096609 DOI: 10.1016/j.jmbbm.2023.106298] [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: 01/13/2023] [Revised: 09/19/2023] [Accepted: 12/02/2023] [Indexed: 01/09/2024]
Abstract
Skeletal muscle is a hierarchical structure composed of multiple organizational scales. A major challenge in the biomechanical evaluation of muscle relates to the difficulty in evaluating the experimental mechanical properties at the different organizational levels of the same tissue. Indeed, the ability to integrate mechanical properties evaluated at various levels will allow for improved assessment of the entire tissue, leading to a better understanding of how changes at each level evolve over time and/or impact tissue function, especially in the case of muscle diseases. Therefore, the purpose of this study was to analyze a genetically engineered mouse model (Klf10 KO: Krüppel-Like Factor 10 knockout) with known skeletal muscle defects to compare the mechanical properties with wild-type (WT) controls at the three main muscle scales: the macroscopic (whole muscle), microscopic (fiber) and submicron (myofibril) levels. Passive mechanical tests (ramp, relaxation) were performed on two types of skeletal muscle (soleus and extensor digitorum longus (EDL)). Results of the present study revealed muscle-type specific behaviors in both genotypes only at the microscopic scale. Interestingly, loss of Klf10 expression resulted in increased passive properties in the soleus but decreased passive properties in the EDL compared to WT controls. At the submicron scale, no changes were observed between WT and Klf10 KO myofibrils for either muscle; these results demonstrate that the passive property differences observed at the microscopic scale (fiber) are not caused by sarcomere intrinsic alterations but instead must originate outside the sarcomeres, likely in the collagen-based extracellular matrix. The macroscopic scale revealed similar passive mechanical properties between WT and Klf10 KO hindlimb muscles. The present study has allowed for a better understanding of the role of Klf10 on the passive mechanical properties of skeletal muscle and has provided reference data to the literature which could be used by the community for muscle multiscale modeling.
Collapse
Affiliation(s)
- Y Tatarenko
- Sorbonne University, Université de Technologie de Compiègne, CNRS UMR 7338, Biomechanics and Bioengineering, Compiègne, France; ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
| | - M Li
- University of Calgary, Faculty of Kinesiology, Human Performance Laboratory, Calgary, Alberta, Canada
| | - P Pouletaut
- Sorbonne University, Université de Technologie de Compiègne, CNRS UMR 7338, Biomechanics and Bioengineering, Compiègne, France
| | - M Kammoun
- Sorbonne University, Université de Technologie de Compiègne, CNRS UMR 7338, Biomechanics and Bioengineering, Compiègne, France
| | - J R Hawse
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - V Joumaa
- University of Calgary, Faculty of Kinesiology, Human Performance Laboratory, Calgary, Alberta, Canada
| | - W Herzog
- University of Calgary, Faculty of Kinesiology, Human Performance Laboratory, Calgary, Alberta, Canada
| | - S Chatelin
- ICube, CNRS UMR 7357, University of Strasbourg, Strasbourg, France
| | - S F Bensamoun
- Sorbonne University, Université de Technologie de Compiègne, CNRS UMR 7338, Biomechanics and Bioengineering, Compiègne, France.
| |
Collapse
|
2
|
Pöhler GH, Klimeš F, Winther H, Wacker F, Ringe KI. Evaluation of tissue shrinkage after CT-guided microwave ablation in patients with liver malignancies using Jacobian determinant. Int J Hyperthermia 2022; 39:1371-1378. [PMID: 36266247 DOI: 10.1080/02656736.2022.2134593] [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: 10/24/2022] Open
Abstract
PURPOSE To assess short-term tissue shrinkage in patients with liver malignancies undergoing computed tomography (CT)-guided microwave ablation (MWA) using Jacobian determinant (JD). MATERIALS AND METHODS Twenty-nine patients with 29 hepatic malignancies (primary n = 24; metastases n = 5; median tumor diameter 18 mm) referred to CT-guided MWA (single position; 10 min, 100 W) were included in this retrospective IRB-approved study, after exclusion of five patients. Following segmentation of livers and tumors on pre-interventional images, segmentations were registered on post-interventional images. JD mapping was applied to quantify voxelwise tissue volume changes after MWA. Percentual volume changes were evaluated in the ablated tumor, a 5-cm tumor perimeter and in the whole liver and compared in different clinical conditions (tumor entity: primary vs. secondary; tumor location: subcapsular vs. non-subcapsular; tumor volume: >/<6 ml: cirrhosis: yes vs. no; prior chemotherapy: yes vs. no using Shapiro-Wilk, χ2 and Wilcoxon rank sum tests, respectively (with p < 0.05 deemed significant). RESULTS Tissue volume change was 0.6% in the ablated tumor, 1.6% in the 5-cm perimeter and 0.3% in the whole liver. Shrinkage in the ablated tumor was pronounced in non-subcapsular located tumors, whereas tissue expansion was noted in subcapsular tumors (median -3.5 vs. 1.1%; p = 0.0195). Shrinkage in the whole liver was higher in tumor volumes >6ml, compared with smaller tumors, in which tissue expansion was noted (median -1.0 vs. 2.5%; p = 0.002). Other clinical conditions had no significant influence on the extent of tissue shrinkage (p > 0.05). CONCLUSION 3D Jacobian analysis shows that hepatic tissue deformation following MWA is most pronounced in a 5-cm area surrounding the treated tumor. Tumor location and tumor volume may have an impact on the extent of tissue shrinkage which may affect estimation of the safety margin.
Collapse
Affiliation(s)
- Gesa H Pöhler
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Filip Klimeš
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Hinrich Winther
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Frank Wacker
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Kristina I Ringe
- Department of Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| |
Collapse
|
3
|
Singh G, Chanda A. Mechanical properties of whole-body soft human tissues: a review. Biomed Mater 2021; 16. [PMID: 34587593 DOI: 10.1088/1748-605x/ac2b7a] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 09/29/2021] [Indexed: 11/11/2022]
Abstract
The mechanical properties of soft tissues play a key role in studying human injuries and their mitigation strategies. While such properties are indispensable for computational modelling of biological systems, they serve as important references in loading and failure experiments, and also for the development of tissue simulants. To date, experimental studies have measured the mechanical properties of peripheral tissues (e.g. skin)in-vivoand limited internal tissuesex-vivoin cadavers (e.g. brain and the heart). The lack of knowledge on a majority of human tissues inhibit their study for applications ranging from surgical planning, ballistic testing, implantable medical device development, and the assessment of traumatic injuries. The purpose of this work is to overcome such challenges through an extensive review of the literature reporting the mechanical properties of whole-body soft tissues from head to toe. Specifically, the available linear mechanical properties of all human tissues were compiled. Non-linear biomechanical models were also introduced, and the soft human tissues characterized using such models were summarized. The literature gaps identified from this work will help future biomechanical studies on soft human tissue characterization and the development of accurate medical models for the study and mitigation of injuries.
Collapse
Affiliation(s)
- Gurpreet Singh
- Centre for Biomedical Engineering, Indian Institute of Technology (IIT), Delhi, India
| | - Arnab Chanda
- Centre for Biomedical Engineering, Indian Institute of Technology (IIT), Delhi, India.,Department of Biomedical Engineering, All India Institute of Medical Sciences (AIIMS), Delhi, India
| |
Collapse
|
4
|
Yang Y, Yung KL, Hung TWR, Yu KM. Analyzing Liver Surface Indentation for In Vivo Refinement of Tumor Location in Minimally Invasive Surgery. Ann Biomed Eng 2021; 49:1402-1415. [PMID: 33258091 PMCID: PMC8058013 DOI: 10.1007/s10439-020-02698-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 11/18/2020] [Indexed: 10/27/2022]
Abstract
Manual palpation to update the position of subsurface tumor(s) is a normal practice in open surgery, but is not possible through the small incisions of minimally invasive surgery (MIS). This paper proposes a method that has the potential to use a simple constant-force indenter and the existing laparoscopic camera for tumor location refinement in MIS. The indenter floats with organ movement to generate a static surface deformation on the soft tissue, resolving problems of previous studies that require complicated measurement of force and displacement during indentation. By analyzing the deformation profile, we can intraoperatively update the tumor's location in real-time. Indentation experiments were conducted on healthy and "diseased" porcine liver specimens to obtain the deformation surrounding the indenter site. An inverse finite element (FE) algorithm was developed to determine the optimal material parameters of the healthy liver tissue. With these parameters, a computational model of tumorous tissue was constructed to quantitatively evaluate the effects of the tumor location on the induced deformation. By relating the experimental data from the "diseased" liver specimen to the computational results, we estimated the radial distance between the tumor and the indenter, as well as the angular position of the tumor relative to the indenter.
Collapse
Affiliation(s)
- Yingqiao Yang
- Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, R606, 1 Yuk Road, Hung Hom, Kowloon, Hong Kong.
| | - Kai-Leung Yung
- Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, R606, 1 Yuk Road, Hung Hom, Kowloon, Hong Kong
| | - Tin Wai Robert Hung
- Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, R606, 1 Yuk Road, Hung Hom, Kowloon, Hong Kong
| | - Kai-Ming Yu
- Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, R606, 1 Yuk Road, Hung Hom, Kowloon, Hong Kong
| |
Collapse
|
5
|
Malečková A, Kochová P, Pálek R, Liška V, Mik P, Bońkowski T, Horák M, Tonar Z. Blunt injury of liver: mechanical response of porcine liver in experimental impact test. Physiol Meas 2021; 42:025008. [PMID: 33482651 DOI: 10.1088/1361-6579/abdf3c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE The liver is frequently injured in blunt abdominal trauma caused by road traffic accidents. The testing of safety performance of vehicles, e.g. belt usage, head support, seat shape, or air bag shape, material, pressure and reaction, could lead to reduction of the injury seriousness. Current trends in safety testing include development of accurate computational human body models (HBMs) based on the anatomical, morphological, and mechanical behavior of tissues under high strain. APPROACH The aim of this study was to describe the internal pressure changes within porcine liver, the severity of liver injury and the relation between the porcine liver microstructure and rupture propagation in an experimental impact test. Porcine liver specimens (n = 24) were uniformly compressed using a drop tower technique and four impact heights (200, 300, 400 and 500 mm; corresponding velocities: 1.72, 2.17, 2.54 and 2.88 m s-1). The changes in intravascular pressure were measured via catheters placed in portal vein and caudate vena cava. The induced injuries were analyzed on the macroscopic level according to AAST grade and AIS severity. Rupture propagation with respect to liver microstructure was analyzed using stereological methods. MAIN RESULTS Macroscopic ruptures affected mostly the interface between connective tissue surrounding big vessels and liver parenchyma. Histological analysis revealed that the ruptures avoided reticular fibers and interlobular septa made of connective tissue on the microscopic level. SIGNIFICANCE The present findings can be used for evaluation of HBMs of liver behavior in impact situations.
Collapse
Affiliation(s)
- Anna Malečková
- Department of Histology and Embryology, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Petra Kochová
- European Centre of Excellence NTIS, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic
| | - Richard Pálek
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Department of Surgery, Faculty of Medicine and University Hospital in Pilsen, Charles University, Pilsen, Czech Republic
| | - Václav Liška
- Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic.,Department of Surgery, Faculty of Medicine and University Hospital in Pilsen, Charles University, Pilsen, Czech Republic
| | - Patrik Mik
- Department of Anatomy, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Tomasz Bońkowski
- New Technologies-Research Centre, University of West Bohemia, Pilsen, Czech Republic
| | - Miroslav Horák
- Department of Mechanics, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic
| | - Zbyněk Tonar
- European Centre of Excellence NTIS, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic
| |
Collapse
|
6
|
Quantifying tactile properties of liver tissue, silicone elastomers, and a 3D printed polymer for manufacturing realistic organ models. J Mech Behav Biomed Mater 2020; 104:103630. [DOI: 10.1016/j.jmbbm.2020.103630] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 01/17/2023]
|
7
|
Kammoun M, Pouletaut P, Nguyen TN, Subramaniam M, Hawse JR, Bensamoun SF. The Effect of Freezing Time on Muscle Fiber Mechanical Properties. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:5356-5359. [PMID: 31947066 DOI: 10.1109/embc.2019.8857804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this study was to investigate the effect of freezing time on the functional behavior of mouse muscle fibers. Passive mechanical tests were performed on single soleus muscle fibers from fresh (0 month) and preserved (stored at -20°C for 3, 6, 9 and 12 months) 3 month old mice. The Young's modulus and the dynamic and the static stresses were measured. A viscoelastic Hill model of 3rd order was used to fit the experimental relaxation test data. The statistical analysis corresponding to the elastic modulus of single muscle fibers did not differ when comparing fresh and stored samples for 3 and 6 months at -20 °C. From 9 months, fibers were less resistant and the mechanical properties were damaged. The primary goal of this study was to complete the gold standard process of muscle fiber preservation for subsequent mechanical property studies. We have demonstrated that muscle fibers can be stored at -20°C for up to 6 months without altering their mechanical properties.
Collapse
|
8
|
Balog S, Li Y, Ogawa T, Miki T, Saito T, French SW, Asahina K. Development of Capsular Fibrosis Beneath the Liver Surface in Humans and Mice. Hepatology 2020; 71:291-305. [PMID: 31206736 PMCID: PMC6918014 DOI: 10.1002/hep.30809] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 06/11/2019] [Indexed: 12/13/2022]
Abstract
Glisson's capsule is the connective tissue present in the portal triad as well as beneath the liver surface. Little is known about how Glisson's capsule changes its structure in capsular fibrosis (CF), which is characterized by fibrogenesis beneath the liver surface. In this study, we found that the human liver surface exhibits multilayered capsular fibroblasts and that the bile duct is present beneath the mesothelium, whereas capsular fibroblasts are scarce and no bile ducts are present beneath the mouse liver surface. Patients with cirrhosis caused by alcohol abuse or hepatitis C virus infection show development of massive CF. To examine the effect of alcohol on CF in mice, we first injected chlorhexidine gluconate (CG) intraperitoneally and then fed alcohol for 1 month. The CG injection induces CF consisting of myofibroblasts beneath the mesothelium. One month after CG injection, the fibrotic area returns to the normal structure. In contrast, additional alcohol feeding sustains the presence of myofibroblasts in CF. Cell lineage tracing revealed that mesothelial cells give rise to myofibroblasts in CF, but these myofibroblasts disappear 1 month after recovery with or without alcohol feeding. Capsular fibroblasts isolated from the mouse liver spontaneously differentiated into myofibroblasts and their differentiation was induced by transforming growth factor beta 1 (TGF-β1) or acetaldehyde in culture. In alcohol-fed mice, infiltrating CD11b+ Ly-6CLow/- monocytes had reduced mRNA expression of matrix metalloproteinase 13 and matrix metalloproteinase 9 and increased expression of tissue inhibitor of matrix metalloproteinase 1, Tgfb1, and interleukin-10 during resolution of CF. Conclusion: The present study revealed that the structure of Glisson's capsule is different between human and mouse livers and that alcohol impairs the resolution of CF by changing the phenotype of Ly-6CLow/- monocytes.
Collapse
Affiliation(s)
- Steven Balog
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, Keck School of Medicine, University of Southern California, CA, USA
| | - Yuchang Li
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, Keck School of Medicine, University of Southern California, CA, USA
| | - Tomohiro Ogawa
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, Keck School of Medicine, University of Southern California, CA, USA.,Center for the Advancement of Higher Education, Faculty of Engineering, Kindai University, Hiroshima, Japan
| | - Toshio Miki
- Department of Surgery, Keck School of Medicine, University of Southern California, CA, USA
| | - Takeshi Saito
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, Keck School of Medicine, University of Southern California, CA, USA.,Department of Medicine, Keck School of Medicine, University of Southern California, CA, USA
| | | | - Kinji Asahina
- Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, Keck School of Medicine, University of Southern California, CA, USA.,Contact Information: Kinji Asahina, Ph.D., FAASLD, Southern California Research Center for ALPD and Cirrhosis, Department of Pathology, Keck School of Medicine, University of Southern California, 1333 San Pablo St., MMR402, Los Angeles, CA 90033-9141, Tel: 323-442-2213, Fax: 323-442-3126,
| |
Collapse
|
9
|
Bose P, Eyckmans J, Nguyen TD, Chen CS, Reich DH. Effects of Geometry on the Mechanics and Alignment of Three-Dimensional Engineered Microtissues. ACS Biomater Sci Eng 2018; 5:3843-3855. [DOI: 10.1021/acsbiomaterials.8b01183] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Prasenjit Bose
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jeroen Eyckmans
- Department of Biomedical Engineering and the Biological Design Center, Boston University, Boston, Massachusetts 02215, United States
- The Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
| | - Thao D. Nguyen
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Christopher S. Chen
- Department of Biomedical Engineering and the Biological Design Center, Boston University, Boston, Massachusetts 02215, United States
- The Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
| | - Daniel H. Reich
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, United States
| |
Collapse
|
10
|
Characterization of perfused and sectioned liver tissue in a full indentation cycle using a visco-hyperelastic model. J Mech Behav Biomed Mater 2018; 90:591-603. [PMID: 30500697 DOI: 10.1016/j.jmbbm.2018.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 10/09/2018] [Accepted: 11/04/2018] [Indexed: 12/22/2022]
Abstract
Realistic modeling of biologic material is required for optimizing fidelity in computer-aided surgical training and assistance systems. The modeling of liver tissue has remained challenging due to its nonlinear viscoelastic properties and high hysteresis of the stress-strain relation. While prior studies have described the behavior of liver tissue during the loading status (in elongation, compression, or indentation tests) or unloading status (in stress relaxation or creep tests), a hysteresis curve with both loading and unloading processes was incompletely defined. We seek to use a single material model to characterize the mechanical properties of liver tissue in a full indentation cycle ex vivo perfused and then sectioned. Based on measurements taken from ex-vivo perfused porcine livers, we converted force-displacement curves to stress-strain curves and developed a visco-hyperelastic constitutive model to characterize the liver's mechanical behavior at different locations under various rates of indentation (1, 2, 5, 10, and 20 mm/s). The proposed model is a mixed visco-hyperelastic model with up to 6 coefficients. The normalized root mean square standard deviations of fitted curves are less than 5% and 10% in low (<0.05) and high strain (>0.3) conditions respectively.
Collapse
|
11
|
Dunford KM, LeRoith T, Kemper AR. Effects of postmortem time and storage fluid on the material properties of bovine liver parenchyma in tension. J Mech Behav Biomed Mater 2018; 87:240-255. [PMID: 30096512 DOI: 10.1016/j.jmbbm.2018.05.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 11/28/2022]
Abstract
In motor vehicle collisions (MVCs), liver injuries are one of the most frequently reported types of abdominal organ trauma. Although finite element models are utilized to evaluate the risk of sustaining an abdominal organ injury in MVCs, these models must be validated based on biomechanical data in order to accurately assess injury risk. Given that previous studies that have quantified the tensile failure properties of human liver parenchyma have been limited to testing at 48 h postmortem, it is currently unknown how the material properties change between time of death and 48 h postmortem. Therefore, the objective of this study was to quantify the effects of postmortem degradation on the tensile material properties of bovine liver parenchyma with increasing postmortem time when stored in DMEM or saline. A total of 148 uniaxial tension tests were successfully conducted on parenchyma samples of fourteen bovine livers acquired immediately after death. Liver tissue was submerged in DMEM or saline and kept cool during sample preparation and storage. Twelve livers were stored as large blocks of tissue, while two livers were stored as small blocks and slices. Tension tests were performed on multiple dog-bone samples from each liver at three time points: ~6 h, ~24 h, and ~48 h postmortem. The data were then analyzed using a Linear Mixed Effect Model to determine if there were significant changes in the failure stress, failure strain, and modulus with respect to postmortem time. The results of the current study showed that the failure strain of bovine liver parenchyma decreased significantly between 6 h and 48 h after death when stored as large blocks in saline and refrigerated. Conversely, neither the failure stress nor failure strain changed significantly with respect to postmortem time when stored as large blocks in DMEM. The modulus did not change significantly with respect to postmortem time for tissue stored as large blocks in either saline or DMEM. Cellular disruption increased with postmortem time for tissue stored as large blocks, with tissue stored in saline showing the greatest increase at each time point. In addition, preliminary results indicated that reducing the tissue storage size had a negative effect on the material properties and cellular architecture. Overall, this study illustrated that the effects of postmortem liver degradation varied with respect to the preservation fluid, storage time, and storage block size.
Collapse
Affiliation(s)
- Kristin M Dunford
- Virginia Tech, Center for Injury Biomechanics, Department of Biomedical Engineering and Mechanics, 440 Kelly Hall, 325 Stanger St., Blacksburg, VA 24061, USA.
| | - Tanya LeRoith
- Virginia-Maryland College of Veterinary Medicine, Anatomic Pathology, Department of Biomedical Sciences & Pathobiology, 132 IDRF, 295 Duckpond Dr., Blacksburg, VA 24061, USA.
| | - Andrew R Kemper
- Virginia Tech, Center for Injury Biomechanics, Department of Biomedical Engineering and Mechanics, 449 Kelly Hall, 325 Stanger St., Blacksburg, VA 24061, USA.
| |
Collapse
|
12
|
De S, Rosen J, Dagan A, Hannaford B, Swanson P, Sinanan M. Assessment of Tissue Damage due to Mechanical Stresses. Int J Rob Res 2016. [DOI: 10.1177/0278364907082847] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
While there are many benefits to minimally invasive surgery (MIS), force feedback or touch sensation is limited in the currently available MIS tools, such as surgical robots, creating the potential for excessive force application during surgery and unintended tissue injury. The goal of this work was to develop a methodology with which to identify stress magnitudes and durations that can be safely applied with a MIS grasper to di ferent tissues, potentially improving MIS device design and reducing potentially adverse clinically relevant consequences. Using the porcine model, stresses typically applied in MIS were applied to liver, ureter and small bowel using a motorized endoscopic grasper. Acute indicators of tissue damage including cellular death and infiltration of inflammatory cells were measured using histological and image analysis techniques. Finite element analysis was used to identify approximate stress distributions experienced by the tissues. Parameters used in these finite element models specifically reflected the properties of liver, which served as an initial proxy for all tissues, as stress distributions rather than absolute values were desired. Local regions predicted to have uniform stress by the computational models were mapped to and analyzed in the tissue samples for acute damage. Analysis of variance (ANOVA) and post-hoc analyses were used to detect stress magnitudes and durations that caused significantly increased tissue damage with the goal to ultimately identify safe stress `thresholds' during grasping of the studied tissues. Preliminary data suggests a graded non-linear response between applied stress magnitude and apoptosis in liver and small bowel as well as neutrophil infiltration in the small bowel. The ureter appeared to be more resistant to injury at the tested stress levels. By identifying stress magnitudes and durations within the range of grasping loads applied in MIS, it may be possible for researchers to create a `smart' surgical robot that can guide a surgeon to manipulate tissues with minimal resulting damage. In addition, surgical simulator design can be improved to reflect more realistic tissue responses and evaluate trainees' tissue handling skills.
Collapse
Affiliation(s)
- Smita De
- BioRobotics Laboratory, Department of Bioengineering University of Washington Box 352500, Seattle, WA 98195-2500, USA {sd6, rosen}@u.washington.edu, ,
| | - Jacob Rosen
- BioRobotics Laboratory, Department of Bioengineering University of Washington Box 352500, Seattle, WA 98195-2500, USA {sd6, rosen}@u.washington.edu, ,
| | - Aylon Dagan
- BioRobotics Laboratory, Department of Bioengineering University of Washington Box 352500, Seattle, WA 98195-2500, USA {sd6, rosen}@u.washington.edu, ,
| | - Blake Hannaford
- BioRobotics Laboratory, Department of Bioengineering University of Washington Box 352500, Seattle, WA 98195-2500, USA {sd6, rosen}@u.washington.edu, ,
| | - Paul Swanson
- Department of Anatomic Pathology University of Washington Box 352500, Seattle, WA 98195-2500, USA
| | - Mika Sinanan
- Department of Surgery, University of Washington Box 352500, Seattle, WA 98195-2500, USA
| |
Collapse
|
13
|
Bircher K, Ehret AE, Mazza E. Mechanical Characteristics of Bovine Glisson's Capsule as a Model Tissue for Soft Collagenous Membranes. J Biomech Eng 2016; 138:2530163. [DOI: 10.1115/1.4033917] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Indexed: 01/19/2023]
Abstract
An extensive multiaxial experimental campaign on the monotonic, time- and history-dependent mechanical response of bovine Glisson's capsule (GC) is presented. Reproducible characteristics were observed such as J-shaped curves in uniaxial and biaxial configurations, large lateral contraction, cyclic tension softening, large tension relaxation, and moderate creep strain accumulation. The substantial influence of the reference state selection on the kinematic response and the tension versus stretch curves is demonstrated and discussed. The parameters of a large-strain viscoelastic constitutive model were determined based on the data of uniaxial tension relaxation experiments. The model is shown to well predict the uniaxial and biaxial viscoelastic responses in all other configurations. GC, the corresponding model, and the experimental protocols are proposed as a useful basis for future studies on the relation between microstructure and tissue functionality and on the factors influencing the mechanical response of soft collagenous membranes.
Collapse
Affiliation(s)
- Kevin Bircher
- Institute for Mechanical Systems, ETH Zurich, Zurich 8092, Switzerland e-mail:
| | - Alexander E. Ehret
- Institute for Mechanical Systems, ETH Zurich, Zurich 8092, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland e-mail:
| | - Edoardo Mazza
- Institute for Mechanical Systems, ETH Zurich, Zurich 8092, Switzerland; Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf 8600, Switzerland e-mail:
| |
Collapse
|
14
|
Ayyildiz M, Cinoglu S, Basdogan C. Effect of normal compression on the shear modulus of soft tissue in rheological measurements. J Mech Behav Biomed Mater 2015; 49:235-43. [DOI: 10.1016/j.jmbbm.2015.05.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/02/2015] [Accepted: 05/13/2015] [Indexed: 11/24/2022]
|
15
|
Mechanical characterization of human gastrocolic ligament until failure. J Appl Biomater Funct Mater 2015; 13:e106-15. [PMID: 24756780 DOI: 10.5301/jabfm.5000193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2013] [Indexed: 11/20/2022] Open
Abstract
Road accidents can lead to abdominal injuries ranging from severe to lethal, that include hemorrhage of organs and their attachment system. A good understanding and prediction of abdominal injuries therefore requires investigation of the mechanical properties of the attachment systems of abdominal organs. In particular, the gastrocolic ligament (GCL) is one major link between the stomach and the transverse colon. This study aims to investigate the mechanical properties of the GCL under very low and high strain rate uniaxial tensile tests until failure. Thirty-five GCL samples were dissected from 7 embalmed cadavers and tested at a rate of 1 mm/s and 1 m/s. Incidence of freezing was also evaluated. The mechanical response of GCL samples showed an approximately bilinear curve. Within the first linear region (less than 5% of ligament strain), the apparent elastic modulus was estimated at 247±144 kPa, while in the second region, it was estimated at 690±282 kPa. The average failure stress (σfail) and failure strain (εfail) were 131.6±50 kPa and 29%±8%, respectively. High strain rate loading also showed high sensitivity to strain rate. The estimated GCL mechanical properties in this study can be implemented in finite element models of the abdomen to further investigate the mechanical contribution of the organ attachment system under traumatic loading conditions.
Collapse
|
16
|
Lu YC, Kemper AR, Gayzik S, Untaroiu CD, Beillas P. Statistical modeling of human liver incorporating the variations in shape, size, and material properties. STAPP CAR CRASH JOURNAL 2013; 57:285-311. [PMID: 24435736 DOI: 10.4271/2013-22-0012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The liver is one of the most frequently injured abdominal organs during motor vehicle crashes. Realistic numerical assessments of liver injury risk for the entire occupant population require incorporating inter-subject variations into numerical models. The main objective of this study was to quantify the shape variations of human liver in a seated posture and the statistical distributions of its material properties. Statistical shape analysis was applied to construct shape models of the livers of 15 adult human subjects, recorded in a typical seated (occupant) posture. The principal component analysis was then utilized to obtain the modes of variation, the mean model, and 95% statistical boundary shape models. In addition, a total of 52 tensile tests were performed on the parenchyma of three fresh human livers at four loading rates (0.01, 0.1, 1, and 10 s^-1) to characterize the rate-dependent and failure properties of the human liver. A FE-based optimization approach was employed to identify the material parameters of an Ogden material model for each specimen. The mean material parameters were then determined for each loading rate from the characteristic averages of the stress-strain curves, and a stochastic optimization approach was utilized to determine the standard deviations of the material parameters. Results showed that the first five modes of the human liver shape models account for more than 60% of the overall anatomical variations. The distributions of the material parameters combined with the mean and statistical boundary shape models could be used to develop probabilistic finite element (FE) models, which may help to better understand the variability in biomechanical responses and injuries to the abdominal organs under impact loading.
Collapse
Affiliation(s)
- Yuan-Chiao Lu
- Virginia Tech-Wake Forest University, Center for Injury Biomechanics
| | - Andrew R Kemper
- Virginia Tech-Wake Forest University, Center for Injury Biomechanics
| | - Scott Gayzik
- Virginia Tech-Wake Forest University, Center for Injury Biomechanics
| | - Costin D Untaroiu
- Virginia Tech-Wake Forest University, Center for Injury Biomechanics
| | | |
Collapse
|
17
|
Bel-Brunon A, Coret M, Bruyère-Garnier K, Combescure A. Compared prediction of the experimental failure of a thin fibrous tissue by two macroscopic damage models. J Mech Behav Biomed Mater 2013; 27:262-72. [PMID: 23773977 DOI: 10.1016/j.jmbbm.2013.05.019] [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: 10/01/2012] [Revised: 05/16/2013] [Accepted: 05/17/2013] [Indexed: 10/26/2022]
Abstract
Several models for fibrous biological tissues have been proposed in the past, taking into account the fibrous microstructure through different homogenization methods. The aim of this paper is to compare theoretically and experimentally two existing homogenization methods - the Angular Integration method and the Generalized Structure Tensor method - by adapting them to a damage model for a planar fibrous tissue made of linear elastic and brittle fibers. The theoretical implementation of the homogenization methods reveals some differences once damage starts in the fibrous tissue; in particular, the anisotropy of the tissue evolves differently. The experimental aspect of this work consists in identifying the parameters of the damage model, with both homogenization methods, using inflation tests until rupture on a biological membrane. The numerical identification method is based on the simulation of the tests with the real geometry of the samples and the real boundary conditions computed by Stereo Digital Image Correlation. The identification method is applied to human liver capsule. The collagen fibers Young's modulus (19±6MPa) as well as their ultimate longitudinal strain (33±4%) are determined; no significant difference was observed between the two methods. However, by using the experimental boundary conditions, we could observe that the damage progression is faster for the Angular Integration version of the model.
Collapse
Affiliation(s)
- A Bel-Brunon
- Université de Lyon, Lyon F-69000, France; INSA-Lyon, LaMCoS UMR5259, F-69621, France; Ifsttar, UMRT9406, LBMC, F-69675 Bron, France; Université Lyon 1, F-69622 Villeurbanne, France.
| | | | | | | |
Collapse
|
18
|
Umale S, Deck C, Bourdet N, Dhumane P, Soler L, Marescaux J, Willinger R. Experimental mechanical characterization of abdominal organs: liver, kidney & spleen. J Mech Behav Biomed Mater 2012; 17:22-33. [PMID: 23127642 DOI: 10.1016/j.jmbbm.2012.07.010] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 07/10/2012] [Accepted: 07/27/2012] [Indexed: 01/21/2023]
Abstract
Abdominal organs are the most vulnerable body parts during vehicle trauma, leading to high mortality rate due to acute injuries of liver, kidney, spleen and other abdominal organs. Accurate mechanical properties and FE models of these organs are required for simulating the traumas, so that better designing of the accident environment can be done and the organs can be protected from severe damage. Also from biomedical aspect, accurate mechanical properties of organs are required for better designing of surgical tools and virtual surgery environments. In this study porcine liver, kidney and spleen tissues are studied in vitro and hyper-elastic material laws are provided for each. 12 porcine kidneys are used to perform 40 elongation tests on renal capsule and 60 compression tests on renal cortex, 5 porcine livers are used to perform 45 static compression tests on liver parenchyma and 5 porcine spleens are used to carry out 20 compression tests. All the tests are carried out at a static speed of 0.05 mm/s. A comparative analysis of all the results is done with the literature and though the results are of same order of magnitude, a slight dissonance is observed for the renal capsule. It is also observed that the spleen is the least stiff organ in the abdomen whereas the kidney is the stiffest. The results of this study would be essential to develop the FE models of liver, kidney and spleen which can be further used for impact biomechanical and biomedical applications.
Collapse
Affiliation(s)
- Sagar Umale
- Institut de Mécanique des Fluides et des Solides, UNISTRA-CNRS, Strasbourg, France
| | | | | | | | | | | | | |
Collapse
|
19
|
Robot-assisted transvaginal peritoneoscopy using confocal endomicroscopy: a feasibility study in a porcine model. Surg Endosc 2012; 26:2532-40. [DOI: 10.1007/s00464-012-2228-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 02/17/2012] [Indexed: 01/25/2023]
|
20
|
Umale S, Chatelin S, Bourdet N, Deck C, Diana M, Dhumane P, Soler L, Marescaux J, Willinger R. Experimental in vitro mechanical characterization of porcine Glisson's capsule and hepatic veins. J Biomech 2011; 44:1678-83. [DOI: 10.1016/j.jbiomech.2011.03.029] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Revised: 03/22/2011] [Accepted: 03/25/2011] [Indexed: 12/07/2022]
|
21
|
McKee CT, Last JA, Russell P, Murphy CJ. Indentation versus tensile measurements of Young's modulus for soft biological tissues. TISSUE ENGINEERING. PART B, REVIEWS 2011; 17:155-64. [PMID: 21303220 PMCID: PMC3099446 DOI: 10.1089/ten.teb.2010.0520] [Citation(s) in RCA: 393] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 02/07/2011] [Indexed: 12/21/2022]
Abstract
In this review, we compare the reported values of Young's modulus (YM) obtained from indentation and tensile deformations of soft biological tissues. When the method of deformation is ignored, YM values for any given tissue typically span several orders of magnitude. If the method of deformation is considered, then a consistent and less ambiguous result emerges. On average, YM values for soft tissues are consistently lower when obtained by indentation deformations. We discuss the implications and potential impact of this finding.
Collapse
Affiliation(s)
- Clayton T. McKee
- Department of Surgical and Radiological Science, School of Veterinary Medicine, University of California Davis, Davis, California
| | - Julie A. Last
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, Madison, Wisconsin
| | - Paul Russell
- Department of Surgical and Radiological Science, School of Veterinary Medicine, University of California Davis, Davis, California
| | - Christopher J. Murphy
- Department of Surgical and Radiological Science, School of Veterinary Medicine, University of California Davis, Davis, California
- Department of Ophthalmology and Vision Science, School of Medicine, University of California Davis, Davis, California
| |
Collapse
|
22
|
Sala A, Turini G, Ferrari M, Mosca F, Ferrari V. Integration of biomechanical parameters in tetrahedral mass-spring models for virtual surgery simulation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2011; 2011:4550-4554. [PMID: 22255350 DOI: 10.1109/iembs.2011.6091127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Surgical simulation requires to have an operating scenario as similar as possible to the real conditions that the surgeon is going to face. Not only visual and geometric patient properties are needed to be reproduced, but also physical and biomechanical properties are theoretically required. In this paper a physically based patient specific simulator for solid organs is described, recalling the underlying theory and providing simulation results and comparisons. The main biomechanical parameters (Young's modulus and density) have been integrated in a Mass-Spring-Damper model (MSDm) based on a tetrahedral structured network. The proposed algorithms allow the automatic setting of node mass and spring stiffness, while the damping coefficient have been modeled using the Rayleigh approach. Moreover, the method automatically detects the organ external layer, allowing the usage of both the surface and internal Young's moduli: for the capsule (or stroma) and for the internal part (or parenchyma). Finally the model can be manually tuned to represent lesions with specific biomechanical properties. The method has beed tested with various material samples. The results have shown a good visual realism ensuring the performance required by an interactive simulation.
Collapse
Affiliation(s)
- Alessandro Sala
- EndoCAS - Center for Computer Assisted Surgery, University of Pisa, 56124 Pisa, Italy.
| | | | | | | | | |
Collapse
|
23
|
Roan E. The Effect of Glisson’s Capsule on the Superficial Elasticity Measurements of the Liver. J Biomech Eng 2010; 132:104504. [DOI: 10.1115/1.4002369] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In the past decade, novel tools for surgical planning and disease diagnosis have been developed to detect the liver’s mechanical properties. Some tools utilize superficial indentation type measurements to determine the elasticity of the liver parenchyma and to assume material homogeneity. In fact, the liver is a soft tissue covered with a connective sheathing that is called Glisson’s capsule. This article quantifies the effect of this capsule on the measured or “effective” elastic modulus obtained by indentation with a spherical geometry. Two sets of parametric computational studies in which the Glisson capsule thickness and elasticity were varied, demonstrated the relationship between the measured elastic response and the underlying parenchymal elastic response. Previously reported in vivo indentation data on the human liver were utilized to determine the elasticity of its parenchyma. The results indicated a linear relationship between the effective (measured) elastic response and the underlying parenchyma for the Glisson capsule thicknesses considered. When previously published human liver indentation data were analyzed, the measured elastic modulus was nearly 6.9% greater than the underlying parenchyma elastic modulus. Although the analyzed data were obtained from a single liver and yet displayed a significant variation, the Glisson capsule elasticity induced a significant but systematic error as well. The Glisson capsule thickness error was negligible for capsule parameters associated with a normal liver. Based on this work, an emphasis on the Glisson capsule’s contribution to the mechanical response of the liver would enhance the clinical potential of indentation-based novel tools for liver care.
Collapse
Affiliation(s)
- Esra Roan
- Department of Biomedical Engineering, and Department of Mechanical Engineering, University of Memphis, 330 Engineering Technology Building, Memphis, TN 38152
| |
Collapse
|
24
|
Szegedi M, Rassiah-Szegedi P, Fullerton G, Wang B, Salter B. A proto-type design of a real-tissue phantom for the validation of deformation algorithms and 4D dose calculations. Phys Med Biol 2010; 55:3685-99. [PMID: 20530851 DOI: 10.1088/0031-9155/55/13/008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The purpose of this study is to design a real-tissue phantom for use in the validation of deformation algorithms. A phantom motion controller that runs sinusoidal and non-regular patient-based breathing pattern, via a piston, was applied to porcine liver tissue. It was regulated to simulate movement ranges similar to recorded implanted liver markers from patients. 4D CT was applied to analyze deformation. The suitability of various markers in the liver and the position reproducibility of markers and of reference points were studied. The similarity of marker motion pattern in the liver phantom and in real patients was evaluated. The viability of the phantom over time and its use with electro-magnetic tracking devices were also assessed. High contrast markers, such as carbon markers, implanted in the porcine liver produced less image artifacts on CT and were well visualized compared to metallic ones. The repositionability of markers was within a measurement accuracy of +/-2 mm. Similar anatomical patient motions were reproducible up to elongations of 3 cm for a time period of at least 90 min. The phantom is compatible with electro-magnetic tracking devices and 4D CT. The phantom motion is reproducible and simulates realistic patient motion and deformation. The ability to carry out voxel-based tracking allows for the evaluation of deformation algorithms in a controlled environment with recorded patient traces. The phantom is compatible with all therapy devices clinically encountered in our department.
Collapse
Affiliation(s)
- M Szegedi
- Health Science Center, University of Texas, San Antonio, TX, USA.
| | | | | | | | | |
Collapse
|
25
|
Hollenstein M, Jabareen M, Breitenstein S, Riener MO, Clavien PA, Bajka M, Mazza E. Intraoperative mechanical characterization of human liver. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/pamm.200910022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
26
|
Constantinides G, Kalcioglu ZI, McFarland M, Smith JF, Van Vliet KJ. Probing mechanical properties of fully hydrated gels and biological tissues. J Biomech 2008; 41:3285-9. [PMID: 18922534 DOI: 10.1016/j.jbiomech.2008.08.015] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 08/11/2008] [Accepted: 08/14/2008] [Indexed: 11/15/2022]
Abstract
A longstanding challenge in accurate mechanical characterization of engineered and biological tissues is maintenance of both stable sample hydration and high instrument signal resolution. Here, we describe the modification of an instrumented indenter to accommodate nanomechanical characterization of biological and synthetic tissues in liquid media, and demonstrate accurate acquisition of force-displacement data that can be used to extract viscoelastoplastic properties of hydrated gels and tissues. We demonstrate the validity of this approach via elastoplastic analysis of relatively stiff, water-insensitive materials of elastic moduli E>1000 kPa (borosilicate glass and polypropylene), and then consider the viscoelastic response and representative mechanical properties of compliant, synthetic polymer hydrogels (polyacrylamide-based hydrogels of varying mol%-bis crosslinker) and biological tissues (porcine skin and liver) of E<500 kPa. Indentation responses obtained via loading/unloading hystereses and contact creep loading were highly repeatable, and the inferred E were in good agreement with available macroscopic data for all samples. As expected, increased chemical crosslinking of polyacrylamide increased stiffness (E40 kPa) and decreased creep compliance. E of porcine liver (760 kPa) and skin (222 kPa) were also within the range of macroscopic measurements reported for a limited subset of species and disease states. These data show that instrumented indentation of fully immersed samples can be reliably applied for materials spanning several orders of magnitude in stiffness (E=kPa-GPa). These capabilities are particularly important to materials design and characterization of macromolecules, cells, explanted tissues, and synthetic extracellular matrices as a function of spatial position, degree of hydration, or hydrolytic/enzymatic/corrosion reaction times.
Collapse
Affiliation(s)
- Georgios Constantinides
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | | | | | | |
Collapse
|
27
|
Nava A, Mazza E, Furrer M, Villiger P, Reinhart W. In vivo mechanical characterization of human liver. Med Image Anal 2008; 12:203-16. [DOI: 10.1016/j.media.2007.10.001] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 10/01/2007] [Accepted: 10/02/2007] [Indexed: 12/01/2022]
|
28
|
Mazza E, Grau P, Hollenstein M, Bajka M. Constitutive Modeling of Human Liver Based on in Vivo Measurements. MEDICAL IMAGE COMPUTING AND COMPUTER-ASSISTED INTERVENTION – MICCAI 2008 2008; 11:726-33. [DOI: 10.1007/978-3-540-85990-1_87] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
|
29
|
Mazza E, Nava A, Hahnloser D, Jochum W, Bajka M. The mechanical response of human liver and its relation to histology: an in vivo study. Med Image Anal 2007; 11:663-72. [PMID: 17719834 DOI: 10.1016/j.media.2007.06.010] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 05/04/2007] [Accepted: 06/20/2007] [Indexed: 01/15/2023]
Abstract
The mechanical response of human liver is characterized in vivo by means of intra-operative aspiration experiments. Mechanical characterization is combined with histological evaluation of liver tissue biopsies obtained from the resected liver at the site of mechanical testing. This procedure enables a quantitative analysis of the correlation between mechanical response and tissue micro-structure of normal and diseased liver. Ten organs were tested in vivo at multiple locations, as well as ex vivo immediately after resection. Biopsies were analyzed in terms of pathology and percentage of connective tissue content. The change of the mechanical parameters from in vivo to ex vivo has been determined, with an increase of 17% of the proposed stiffness index. The relationship between mechanical parameters and various pathologic conditions affecting the tissue samples has been quantified, with fibrosis leading to a response up to three times stiffer as compared with normal tissue. Increased stiffness can be detected by digital palpation (increased "consistency") and may suggest the presence of a tumor. The present observations suggest that stiffness increase cannot be attributed to the tumoral tissue itself, but rather to the fibrotic stroma that often arise within or adjacent to the tumor. Variation of the mechanical parameters as a function of connective tissue content has been evaluated based on the histological examinations and the results confirm a direct proportionality between stiffness index and connective tissue percentage. The approach described here might eventually lead to a diagnostic procedure and complement other clinical methods, like palpation and ultrasound examination of the liver.
Collapse
Affiliation(s)
- Edoardo Mazza
- Department of Mechanical Engineering, Swiss Federal Institute of Technology, 8092, Zurich, Switzerland.
| | | | | | | | | |
Collapse
|