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Kote VB, Frazer LL, Hostetler ZS, Jones DA, Davis M, Op't Eynde J, Kait J, Pang D, Bass D, Koser J, Shah A, Yoganandan N, Stemper B, Bentley T, Nicolella DP. Investigating the Impact of Blunt Force Trauma: A Probabilistic Study of Behind Armor Blunt Trauma Risk. Ann Biomed Eng 2024:10.1007/s10439-024-03564-3. [PMID: 38922366 DOI: 10.1007/s10439-024-03564-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 06/13/2024] [Indexed: 06/27/2024]
Abstract
Evaluating Behind Armor Blunt Trauma (BABT) is a critical step in preventing non-penetrating injuries in military personnel, which can result from the transfer of kinetic energy from projectiles impacting body armor. While the current NIJ Standard-0101.06 standard focuses on preventing excessive armor backface deformation, this standard does not account for the variability in impact location, thorax organ and tissue material properties, and injury thresholds in order to assess potential injury. To address this gap, Finite Element (FE) human body models (HBMs) have been employed to investigate variability in BABT impact conditions by recreating specific cases from survivor databases and generating injury risk curves. However, these deterministic analyses predominantly use models representing the 50th percentile male and do not investigate the uncertainty and variability inherent within the system, thus limiting the generalizability of investigating injury risk over a diverse military population. The DoD-funded I-PREDICT Future Naval Capability (FNC) introduces a probabilistic HBM, which considers uncertainty and variability in tissue material and failure properties, anthropometry, and external loading conditions. This study utilizes the I-PREDICT HBM for BABT simulations for three thoracic impact locations-liver, heart, and lower abdomen. A probabilistic analysis of tissue-level strains resulting from a BABT event is used to determine the probability of achieving a Military Combat Incapacitation Scale (MCIS) for organ-level injuries and the New Injury Severity Score (NISS) is employed for whole-body injury risk evaluations. Organ-level MCIS metrics show that impact at the heart can cause severe injuries to the heart and spleen, whereas impact to the liver can cause rib fractures and major lacerations in the liver. Impact at the lower abdomen can cause lacerations in the spleen. Simulation results indicate that, under current protection standards, the whole-body risk of injury varies between 6 and 98% based on impact location, with the impact at the heart being the most severe, followed by impact at the liver and the lower abdomen. These results suggest that the current body armor protection standards might result in severe injuries in specific locations, but no injuries in others.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Dale Bass
- Wayne State University, Detroit, MI, USA
| | - Jared Koser
- Medical College of Wisconsin, Milwaukee, WI, USA
| | - Alok Shah
- Medical College of Wisconsin, Milwaukee, WI, USA
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Chaufer M, Delille R, Bourel B, Maréchal C, Lauro F, Mauzac O, Roth S. Review of non-penetrating ballistic testing techniques for protection assessment: From biological data to numerical and physical surrogates. Proc Inst Mech Eng H 2024; 238:383-402. [PMID: 38415326 DOI: 10.1177/09544119241232122] [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] [Indexed: 02/29/2024]
Abstract
Human surrogates have long been employed to simulate human behaviour, beginning in the automotive industry and now widely used throughout the safety framework to estimate human injury during and after accidents and impacts. In the specific context of blunt ballistics, various methods have been developed to investigate wound injuries, including tissue simulants such as clays or gelatine ballistic, physical dummies and numerical models. However, all of these surrogate entities must be biofidelic, meaning they must accurately represent the biological properties of the human body. This paper provides an overview of physical and numerical surrogates developed specifically for blunt ballistic impacts, including their properties, use and applications. The focus is on their ability to accurately represent the human body in the context of blunt ballistic impact.
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Affiliation(s)
- Martin Chaufer
- Interdisciplinary Laboratory Carnot of Bourgogne-Site UTBM, UMR 6303, CNRS/Université Bourgogne Franche-Comté (UBFC), Belfort, France
| | - Rémi Delille
- Univ. Polytechnique Hauts-de-France, CNRS, UMR 8201, LAMIH, Laboratoire d'Automatique de Mécanique et d'Informatique Industrielles et Humaines, Valenciennes, France
| | - Benjamin Bourel
- Univ. Polytechnique Hauts-de-France, CNRS, UMR 8201, LAMIH, Laboratoire d'Automatique de Mécanique et d'Informatique Industrielles et Humaines, Valenciennes, France
| | - Christophe Maréchal
- Univ. Polytechnique Hauts-de-France, CNRS, UMR 8201, LAMIH, Laboratoire d'Automatique de Mécanique et d'Informatique Industrielles et Humaines, Valenciennes, France
| | - Franck Lauro
- Univ. Polytechnique Hauts-de-France, CNRS, UMR 8201, LAMIH, Laboratoire d'Automatique de Mécanique et d'Informatique Industrielles et Humaines, Valenciennes, France
- Insa Hauts-de-France, Valenciennes, France
| | - Olivier Mauzac
- French Ministry of Interior, CREL/DEPAFI, Place Beauvau, Paris, France
| | - Sébastien Roth
- Interdisciplinary Laboratory Carnot of Bourgogne-Site UTBM, UMR 6303, CNRS/Université Bourgogne Franche-Comté (UBFC), Belfort, France
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Du L, Deng H, Wu X, Liu F, Yin T, Zheng J. Relationship Between Spleen Pathologic Changes and Spleen Stiffness in Portal Hypertension Rat Model. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:216-223. [PMID: 37919143 DOI: 10.1016/j.ultrasmedbio.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/16/2023] [Accepted: 10/01/2023] [Indexed: 11/04/2023]
Abstract
OBJECTIVE The aim of the study described here was to explore the influence of splenic pathology and hemodynamic parameters on spleen stiffness in portal hypertension (PH). METHODS A Sprague‒Dawley rat model of PH (n = 34) induced by CCl4 was established, and 9 normal rats were used as controls. All animals underwent a routine ultrasound examination, spleen stiffness measurement (SSM), liver stiffness measurement (LSM), portal vein pressure (PVP) measurement and histopathologic assessment. The diagnostic performance of SSM and LSM in PH was evaluated. SSMs were compared among the groups at different pathologic and hemodynamic levels. Multiple linear regression was used to analyze the factors affecting SSM. RESULTS SSM had excellent diagnostic efficacy for PH (area under the receiver operating characteristic curve [AUC] = 0.900) and was superior to LSM (AUC = 0.794). In a rat model of PH, pathologic changes such as splenic sinus widening, thickening of the splenic capsule and an increase in collagen fibers were observed in the spleen. There were significant differences in SSM at different splenic capsule thicknesses and splenic sinus widths (all p values <0.05), but there were no significant differences in the SSM at different levels of the splenic collagen fiber area and red pulp area (all p values >0.05). In addition, there were significant differences in SSM at different levels of portal vein diameter, blood flow and congestion index (all p values <0.05). Multiple linear regression analysis revealed that PVP, portal vein congestion index and splenic capsule thickness were significantly associated with SSM. CONCLUSION SSM is a good non-invasive way to assess PH. PVP, splenic capsule thickness and portal vein congestion index are responsible for spleen stiffness but not the proliferation of splenic fibrous tissue.
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Affiliation(s)
- Lingyue Du
- Department of Second Affiliated Hospital, School of Medicine, Chinese University of Hong Kong, Shenzhen & Longgang District People's Hospital of Shenzhen, Shenzhen, China; Department of Ultrasound, Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Huan Deng
- Department of Ultrasound, Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Xiaoting Wu
- Department of Second Affiliated Hospital, School of Medicine, Chinese University of Hong Kong, Shenzhen & Longgang District People's Hospital of Shenzhen, Shenzhen, China
| | - Fan Liu
- Department of Second Affiliated Hospital, School of Medicine, Chinese University of Hong Kong, Shenzhen & Longgang District People's Hospital of Shenzhen, Shenzhen, China
| | - Tinghui Yin
- Department of Ultrasound, Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Jian Zheng
- Department of Second Affiliated Hospital, School of Medicine, Chinese University of Hong Kong, Shenzhen & Longgang District People's Hospital of Shenzhen, Shenzhen, China; Department of Ultrasound, Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
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Singh G, Chanda A. Development and Mechanical Characterization of Artificial Surrogates for Brain Tissues. BIOMEDICAL ENGINEERING ADVANCES 2023. [DOI: 10.1016/j.bea.2023.100084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023] Open
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Quasi-Static Mechanical Properties and Continuum Constitutive Model of the Thyroid Gland. J Funct Biomater 2022; 13:jfb13040283. [PMID: 36547544 PMCID: PMC9783632 DOI: 10.3390/jfb13040283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/30/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022] Open
Abstract
The purpose of this study is to obtain the digital twin parameters of the thyroid gland and to build a constitutional model of the thyroid gland based on continuum mechanics, which will lay the foundation for the establishment of a surgical training system for the thyroid surgery robot and the development of the digital twin of the thyroid gland. First, thyroid parenchyma was obtained from fresh porcine thyroid tissue and subjected to quasi-static unconfined uniaxial compression tests using a biomechanical test platform with two strain rates (0.005 s-1 and 0.05 s-1) and two loading orientations (perpendicular to the thyroid surface and parallel to the thyroid surface). Based on this, a tensile thyroid model was established to simulate the stretching process by using the finite element method. The thyroid stretching test was carried out under the same parameters to verify the validity of the hyperelastic constitutive model. The quasi-static mechanical property parameters of the thyroid tissue were obtained by a quasi-static unconstrained uniaxial compression test, and a constitutional model that can describe the quasi-static mechanical properties of thyroid tissue was proposed based on the principle of continuum media mechanics, which is of great value for the establishment of a surgical training system for the head and neck surgery robot and for the development of the thyroid digital twin.
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Kochová P, Malečková A, Pálek R, Liška V, Bońkowski T, Horák M, Grajciarová M, Tonar Z. Porcine spleen as a model organ for blunt injury impact tests: An experimental and histological study. Anat Histol Embryol 2022; 51:576-586. [PMID: 35751561 DOI: 10.1111/ahe.12831] [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: 03/27/2022] [Revised: 06/06/2022] [Accepted: 06/06/2022] [Indexed: 11/30/2022]
Abstract
The spleen is a large and highly vascularized secondary lymphatic organ. Spleen injuries are among the most frequent trauma-related injuries in the abdominal region. The aims of the study were to assess the volume fractions of the main splenic tissue components (red pulp, white pulp, trabeculae and reticular fibres) and to determine the severity of splenic injury due to the experimental impact test. Porcine spleens (n = 17) were compressed by 6.22 kg wooden plate using a drop tower technique from three impact heights (50, 100 and 150 mm corresponding to velocities 0.79, 1.24 and 1.58 m/s). The pressure was measured via catheters placed in the splenic vein. The impact velocity was measured using lasers. The severity of induced injuries was analysed on the macroscopic level. The volume fractions of splenic components were assessed microscopically using stereology. The volume fraction of the red pulp was 76.4%, white pulp 21.3% and trabeculae 2.7% respectively. All impact tests, even with the low impact velocities, led to injuries that occurred mostly in the dorsal extremity of the spleen, and were accompanied by bleeding, capsule rupture and parenchyma crushing. Higher impact height (impact velocity and impact energy) caused more severe injury. Porcine spleen had the same volume fraction of tissue components as human spleen, therefore we concluded that the porcine spleen was a suitable organ model for mechanical experiments. Based on our observations, regions around hilum and the diaphragmatic surface of the dorsal extremity, that contained fissures and notches, were the most prone to injury and required considerable attention during splenic examination after injury. The primary mechanical data are now available for the researchers focused on the splenic trauma modelling.
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Affiliation(s)
- Petra Kochová
- European Centre of Excellence NTIS, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic
| | - Anna Malečková
- Department of Histology and Embryology and Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Richard Pálek
- Department of Surgery and Biomedical Center, Faculty of Medicine and University Hospital in Pilsen, Charles University, Pilsen, Czech Republic
| | - Václav Liška
- Department of Surgery and Biomedical Center, Faculty of Medicine and University Hospital 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
| | - Martina Grajciarová
- Department of Histology and Embryology and Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic
| | - Zbyněk Tonar
- European Centre of Excellence NTIS, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic
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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: 78] [Impact Index Per Article: 26.0] [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.
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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
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Nelson SJ, Creechley JJ, Wale ME, Lujan TJ. Print-A-Punch: A 3D printed device to cut dumbbell-shaped specimens from soft tissue for tensile testing. J Biomech 2020; 112:110011. [DOI: 10.1016/j.jbiomech.2020.110011] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 11/16/2022]
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Biomechanical properties of abdominal organs under tension with special reference to increasing strain rate. J Biomech 2020; 109:109914. [PMID: 32807339 DOI: 10.1016/j.jbiomech.2020.109914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 05/29/2020] [Accepted: 06/21/2020] [Indexed: 01/27/2023]
Abstract
Currently, abdominal finite element models overlook the organs such as gallbladder, bladder, and intestines, which instead are modeled as a simple bag that is not included in the analysis. Further characterization of the material properties is required for researchers to include these organs into models. This study characterized the mechanical properties of human and porcine gallbladder, bladder, and intestines using uniaxial tension loading from the rates of 25%/s to 500%/s. Small differences were observed between human and porcine gallbladder elastic modulus, failure stress, and failure strain. Strain rate was determined to be a significant factor for predicting porcine gallbladder elastic modulus and failure stress which were found to be 9.03 MPa and 1.83 MPa at 500%/s. Human bladder was observed to be slightly stiffer with a slightly lower failure stress than porcine specimens. Both hosts, however, demonstrated a strain rate dependency with the elastic modulus and failure stress increasing as the rate increased with the highest elastic modulus (2.16 MPa) and failure stress (0.65 MPa) occurring at 500%/s. Both human and porcine intestines were observed to be affected by the strain rate. Failure stress was found to be 1.6 MPa and 1.42 MPa at 500%/s for the human and porcine intestines respectively. For all properties found to be strain rate dependent, a numerical model was created to quantify the impact. These results will enable researchers to create more detailed finite element models that include the gallbladder, bladder, and intestines.
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Johnson B, Campbell S, Campbell-Kyureghyan N. The differences in measured prostate material properties between probing and unconfined compression testing methods. Med Eng Phys 2020; 80:44-51. [PMID: 32381284 DOI: 10.1016/j.medengphy.2020.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 01/21/2020] [Accepted: 03/01/2020] [Indexed: 01/20/2023]
Abstract
Characterization of the mechanical properties of organs is important for determining their behavior under load and understanding and predicting their response. In order to appropriately understand behavior, including developing predictive models, the method used to measure the properties should match the application as different testing techniques can yield different results. One of the organs where little mechanical testing has been performed is the prostate. Therefore, the goal of this paper is to expand the knowledge of prostate gland mechanical behavior by using two different compressive testing methods under various loading rates. No differences were found between the elastic modulus measured using the compression and probing protocols for both human and porcine specimens. The elastic modulus ranged from 0.08 MPa at 1%/s to 0.24 MPa at 25%/s for human specimens and from 0.2 MPa at 1%/s to 0.4 MPa at 25%/s for porcine specimens. A strain rate dependency of the elastic modulus was observed for both testing methods. The dependency on strain rate started to saturate at higher rates and a material model was created to quantify this dependence as well as the stress-strain behavior. No strain rate dependency was observed for failure stress or failure strain. Overall, similar values of elastic modulus were found for both probing and compression protocols and the relationship developed between elastic modulus and strain rate could be implemented in models of the prostate gland to aid in understanding the response to dynamic loads.
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Affiliation(s)
- Blake Johnson
- Industrial and Manufacturing Engineering Department, College of Engineering and Applied Science, University of Wisconsin-Milwaukee, 3200N Cramer St., Milwaukee, WI 53211, United States
| | - Scott Campbell
- Structural Analysis Consulting Group, PO Box 170735, Milwaukee, WI 53217, United States
| | - Naira Campbell-Kyureghyan
- Industrial and Manufacturing Engineering Department, College of Engineering and Applied Science, University of Wisconsin-Milwaukee, 3200N Cramer St., Milwaukee, WI 53211, United States; Department of Mechanical Engineering, School of Science and Engineering, Merrimack College, 315 Turnpike St., N Andover, MA 01845, United States.
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11
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Wang D, Xiong Y, Zhang B, Zhang YF, Rosen D, Ge Q. Design framework for mechanically tunable soft biomaterial composites enhanced by modified horseshoe lattice structures. SOFT MATTER 2020; 16:1473-1484. [PMID: 31971207 DOI: 10.1039/c9sm02119a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Soft biomaterials have a wide range of applications in many areas. However, one material can only cover a specific range of mechanical performance such as the elastic modulus and stretchability. In order to improve the mechanical performance of soft biomaterials, lattice structures are embedded to reinforce the biomaterials. In this paper, rectangular and triangular lattice structures formed by modified horseshoe microstructures are used because their mechanical properties are tunable and can be tailored precisely to match the desired properties by adjusting four geometrical parameters, the length L, radius R, width w and arc angle θ0. A theoretical design framework for the modified horseshoe lattice structures is developed to predict the dependence of the mechanical behaviors on geometrical parameters. Both experiments and finite element simulations on lattice structures are conducted to validate the theoretical models. Results show that a wide range of design space for the elastic modulus (a few kPa to hundreds of MPa), stretchability (strain up to 180%) and Poisson ratio (ranging from -0.5 to 1.2) can be achieved. Experiments on lattice-hydrogel composites are also conducted to verify the reinforcement effect of lattice structures on the hydrogel. This work provides a theoretical method to predict the mechanical behaviors of the lattice structures and aid the rational design of reinforced biomaterials, which has applications in tissue engineering, drug delivery and intraocular lenses.
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Affiliation(s)
- Dong Wang
- Robotics Institute, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
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12
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The effect of steatosis and fibrosis on blunt force vulnerability of the liver. Int J Legal Med 2020; 134:1067-1072. [PMID: 31938832 PMCID: PMC7181547 DOI: 10.1007/s00414-019-02245-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 12/30/2019] [Indexed: 01/22/2023]
Abstract
The aim of our study was to examine the possible effect of steatosis and fibrosis on the blunt force vulnerability of human liver tissue. 3.5 × 3.5 × 2-cm-sized liver tissue blocks were removed from 135 cadavers. All specimens underwent microscopical analysis. The tissue samples were put into a test stand, and a metal rod with a square-shaped head was pushed against the capsular surface. The force (Pmax) causing liver rupture was measured and registered with a Mecmesin AFG-500 force gauge. Six groups were formed according to the histological appearance of the liver tissue: intact (group 1), mild steatosis (group 2), moderate steatosis (group 3), severe steatosis (group 4), fibrosis (group 5), and cirrhosis (group 6). The average Pmax value was 34.1 N in intact liver samples (range from 18.1 to 60.8 N, SD ± 8.7), 45.1 N in mild steatosis (range from 24.2 to 79.8 N SD ± 12.6), 55.4 N in moderate steatosis (range from 28.9 to 92.5 N, SD ± 16.0), 57.6 N in severe steatosis (range from 39.8 to 71.5 N, SD ± 11.9), 63.7 N in fibrosis (range from 37.8 to 112.2 N, SD ± 19.5), and 87.1 N in the case of definite cirrhosis (range from 52.7 to 162.7 N, 30.3). The Pmax values were significantly higher in samples with visible structural change than in intact liver sample (p = 0.023, 0.001, 0.009, 0.0001, 0.0001 between group 1 and groups 2 to 6 respectively). Significant difference was found between mild steatosis (group 2) and cirrhosis (group 6) (p = 0.0001), but the difference between mild, moderate, and severe steatosis (groups 2, 3, and 4) was not significant. Our study demonstrated that contrary to what is expected as received wisdom dictates, the diseases of the parenchyma (steatosis and presence of fibrosis) positively correlate with the blunt force resistance of the liver tissue.
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Higginson SM, Sheets NW, Sue LP, Wolfe MM, Kwok AM, Dirks RC, Doggett RS, Gopal VC, Davis JW. Changes in splenic capsule with aging; beliefs and reality. Am J Surg 2019; 220:178-181. [PMID: 31623879 DOI: 10.1016/j.amjsurg.2019.09.035] [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: 04/13/2019] [Revised: 09/20/2019] [Accepted: 09/26/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Research describing the splenic capsule and its effect on non-operative management of splenic injuries is limited. The aim of this study is to identify the current beliefs about the splenic capsule thickness and investigate changes in the splenic capsule with age. METHODS Trauma Medical Directors were surveyed on their beliefs regarding splenic capsule thickness changes with age. Thicknesses of cadaveric splenic capsule samples were measured. RESULTS The majority of trauma medical directors (59%) believe the capsule thickness decreases with age. There were 94 splenic specimens obtained. The splenic capsules of infants were thin and had a uniform layer of elastin fibers. With aging, the capsule becomes thick and develops a collagen layer. CONCLUSION Most trauma directors believe the splenic capsule thickness decreases with age. However, our results demonstrate that the splenic capsule thickness increases during childhood but remains constant in adulthood.
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Affiliation(s)
- Sara M Higginson
- Department of Surgery, UCSF Fresno, 1st Floor Admin, 2823 Fresno Street, Fresno, CA, 93721, USA; Regions Hospital Burn Center, 640 Jackson Street, St. Paul, MN, 55101, USA.
| | - Nicholas W Sheets
- Department of Surgery, UCSF Fresno, 1st Floor Admin, 2823 Fresno Street, Fresno, CA, 93721, USA.
| | - Lawrence P Sue
- Department of Surgery, UCSF Fresno, 1st Floor Admin, 2823 Fresno Street, Fresno, CA, 93721, USA.
| | - Mary M Wolfe
- Department of Surgery, UCSF Fresno, 1st Floor Admin, 2823 Fresno Street, Fresno, CA, 93721, USA.
| | - Amy M Kwok
- Department of Surgery, UCSF Fresno, 1st Floor Admin, 2823 Fresno Street, Fresno, CA, 93721, USA.
| | - Rachel C Dirks
- Department of Surgery, UCSF Fresno, 1st Floor Admin, 2823 Fresno Street, Fresno, CA, 93721, USA.
| | - Reuben S Doggett
- Retired - Sierra Pathology Associates, 305 Park Creek Dr, Clovis, CA, 93612, USA
| | - Venu C Gopal
- Chief Fresno County Coroner, 3150 East Jefferson Ave, Fresno, CA, 93725, USA.
| | - James W Davis
- Department of Surgery, UCSF Fresno, 1st Floor Admin, 2823 Fresno Street, Fresno, CA, 93721, USA.
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Crump MR, Gong AT, Chai D, Bidinger SL, Pavinatto FJ, Reihsen TE, Sweet RM, MacKenzie JD. Monolithic 3D printing of embeddable and highly stretchable strain sensors using conductive ionogels. NANOTECHNOLOGY 2019; 30:364002. [PMID: 31121565 DOI: 10.1088/1361-6528/ab2440] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Medical training simulations that utilize 3D-printed, patient-specific tissue models improve practitioner and patient understanding of individualized procedures and capacitate pre-operative, patient-specific rehearsals. The impact of these novel constructs in medical training and pre-procedure rehearsals has been limited, however, by the lack of effectively embedded sensors that detect the location, direction, and amplitude of strains applied by the practitioner on the simulated structures. The monolithic fabrication of strain sensors embedded into lifelike tissue models with customizable orientation and placement could address this limitation. The demonstration of 3D printing of an ionogel as a stretchable, piezoresistive strain sensor embedded in an elastomer is presented as a proof-of-concept of this integrated fabrication for the first time. The significant hysteresis and drift inherent to solid-phase piezoresistive composites and the dimensional instability of low-hysteresis piezoresistive liquids inspired the adoption of a 3D-printable piezoresistive ionogel composed of reduced graphene oxide and an ionic liquid. The shear-thinning rheology of the ionogel obviates the need to fabricate additional structures that define or contain the geometry of the sensing channel. Sensors are printed on and subsequently encapsulated in polydimethylsiloxane (PDMS), a thermoset elastomer commonly used for analog tissue models, to demonstrate seamless fabrication. Strain sensors demonstrate geometry- and strain-dependent gauge factors of 0.54-2.41, a high dynamic strain range of 350% that surpasses the failure strain of most dermal and viscus tissue, low hysteresis (<3.5% degree of hysteresis up to 300% strain) and baseline drift, a single-value response, and excellent fatigue stability (5000 stretching cycles). In addition, we fabricate sensors with stencil-printed silver/PDMS electrodes in place of wires to highlight the potential of seamless integration with printed electrodes. The compositional tunability of ionic liquid/graphene-based composites and the shear-thinning rheology of this class of conductive gels endows an expansive combination of customized sensor geometry and performance that can be tailored to patient-specific, high-fidelity, monolithically fabricated tissue models.
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Affiliation(s)
- Michael R Crump
- Department of Material Science & Engineering, University of Washington, Seattle, WA 98195-2120, United States of America
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15
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Mihai LA, Goriely A. How to characterize a nonlinear elastic material? A review on nonlinear constitutive parameters in isotropic finite elasticity. Proc Math Phys Eng Sci 2017; 473:20170607. [PMID: 29225507 PMCID: PMC5719638 DOI: 10.1098/rspa.2017.0607] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/03/2017] [Indexed: 01/22/2023] Open
Abstract
The mechanical response of a homogeneous isotropic linearly elastic material can be fully characterized by two physical constants, the Young’s modulus and the Poisson’s ratio, which can be derived by simple tensile experiments. Any other linear elastic parameter can be obtained from these two constants. By contrast, the physical responses of nonlinear elastic materials are generally described by parameters which are scalar functions of the deformation, and their particular choice is not always clear. Here, we review in a unified theoretical framework several nonlinear constitutive parameters, including the stretch modulus, the shear modulus and the Poisson function, that are defined for homogeneous isotropic hyperelastic materials and are measurable under axial or shear experimental tests. These parameters represent changes in the material properties as the deformation progresses, and can be identified with their linear equivalent when the deformations are small. Universal relations between certain of these parameters are further established, and then used to quantify nonlinear elastic responses in several hyperelastic models for rubber, soft tissue and foams. The general parameters identified here can also be viewed as a flexible basis for coupling elastic responses in multi-scale processes, where an open challenge is the transfer of meaningful information between scales.
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Affiliation(s)
- L Angela Mihai
- School of Mathematics, Cardiff University, Senghennydd Road, Cardiff, CF24 4AG, UK
| | - Alain Goriely
- Mathematical Institute, University of Oxford, Woodstock Road, Oxford, OX2 6GG, UK
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16
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Humphrey C, Kumaratilake J. Ballistics and anatomical modelling – A review. Leg Med (Tokyo) 2016; 23:21-29. [DOI: 10.1016/j.legalmed.2016.09.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/22/2016] [Accepted: 09/05/2016] [Indexed: 01/02/2023]
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17
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Muiznieks LD, Keeley FW. Biomechanical Design of Elastic Protein Biomaterials: A Balance of Protein Structure and Conformational Disorder. ACS Biomater Sci Eng 2016; 3:661-679. [DOI: 10.1021/acsbiomaterials.6b00469] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Lisa D. Muiznieks
- Molecular
Structure and Function Program, Research Institute, The Hospital for Sick Children, 686 Bay Street, Toronto, Ontario, Canada M5G 0A4
| | - Fred W. Keeley
- Molecular
Structure and Function Program, Research Institute, The Hospital for Sick Children, 686 Bay Street, Toronto, Ontario, Canada M5G 0A4
- Department
of Biochemistry and Department of Laboratory Medicine and Pathobiology, 1 King’s College Circle, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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Arndt S, Russell A, Tomas J, Müller P, Shekhar S, Brandstädter K, Bruns C, Wex C. Rupture probability of porcine liver under planar and point loading. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/5/055018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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19
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Arun MWJ, Umale S, Humm JR, Yoganandan N, Hadagali P, Pintar FA. Evaluation of kinematics and injuries to restrained occupants in far-side crashes using full-scale vehicle and human body models. TRAFFIC INJURY PREVENTION 2016; 17 Suppl 1:116-123. [PMID: 27586112 DOI: 10.1080/15389588.2016.1197394] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 05/31/2016] [Indexed: 06/06/2023]
Abstract
OBJECTIVE The objective of the current study was to perform a parametric study with different impact objects, impact locations, and impact speeds by analyzing occupant kinematics and injury estimations using a whole-vehicle and whole-body finite element-human body model (FE-HBM). To confirm the HBM responses, the biofidelity of the model was validated using data from postmortem human surrogate (PMHS) sled tests. METHODS The biofidelity of the model was validated using data from sled experiments and correlational analysis (CORA). Full-scale simulations were performed using a restrained Global Human Body Model Consortium (GHBMC) model seated on a 2001 Ford Taurus model using a far-side lateral impact condition. The driver seat was placed in the center position to represent a nominal initial impact condition. A 3-point seat belt with pretensioner and retractor was used to restrain the GHBMC model. A parametric study was performed using 12 simulations by varying impact locations, impacting object, and impact speed using the full-scale models. In all 12 simulations, the principal direction of force (PDOF) was selected as 90°. The impacting objects were a 10-in.-diameter rigid vertical pole and a movable deformable barrier. The impact location of the pole was at the C-pillar in the first case, at the B-pillar in the second case, and, finally, at the A-pillar in the third case. The vehicle and the GHBMC models were defined an initial velocity of 35 km/h (high speed) and 15 km/h (low speed). Excursion of the head center of gravity (CG), T6, and pelvis were measured from the simulations. In addition, injury risk estimations were performed on head, rib cage, lungs, kidneys, liver, spleen, and pelvis. RESULTS The average CORA rating was 0.7. The shoulder belt slipped in B- and C-pillar impacts but somewhat engaged in the A-pillar case. In the B-pillar case, the head contacted the intruding struck-side structures, indicating higher risk of injury. Occupant kinematics depended on interaction with restraints and internal structures-especially the passenger seat. Risk analysis indicated that the head had the highest risk of sustaining an injury in the B-pillar case compared to the other 2 cases. Higher lap belt load (3.4 kN) may correspond to the Abbreviated Injury Scale (AIS) 2 pelvic injury observed in the B-pillar case. Risk of injury to other soft anatomical structures varied with impact configuration and restraint interaction. CONCLUSION The average CORA rating was 0.7. In general, the results indicated that the high-speed impacts against the pole resulted in severe injuries, higher excursions followed by low-speed pole, high-speed moving deformable barrier (MDB), and low-speed MDB impacts. The vehicle and occupant kinematics varied with different impact setups and the latter kinematics were likely influenced by restraint effectiveness. Increased restraint engagement increased the injury risk to the corresponding anatomic structure, whereas ineffective restraint engagement increased the occupant excursion, resulting in a direct impact to the struck-side interior structures.
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Affiliation(s)
- Mike W J Arun
- a Department of Neurosurgery , Medical College of Wisconsin , Milwaukee , Wisconsin
| | - Sagar Umale
- a Department of Neurosurgery , Medical College of Wisconsin , Milwaukee , Wisconsin
| | - John R Humm
- a Department of Neurosurgery , Medical College of Wisconsin , Milwaukee , Wisconsin
| | - Narayan Yoganandan
- a Department of Neurosurgery , Medical College of Wisconsin , Milwaukee , Wisconsin
| | - Prasanaah Hadagali
- a Department of Neurosurgery , Medical College of Wisconsin , Milwaukee , Wisconsin
| | - Frank A Pintar
- a Department of Neurosurgery , Medical College of Wisconsin , Milwaukee , Wisconsin
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Gaur P, Chawla A, Verma K, Mukherjee S, Lalvani S, Malhotra R, Mayer C. Characterisation of human diaphragm at high strain rate loading. J Mech Behav Biomed Mater 2016; 60:603-616. [DOI: 10.1016/j.jmbbm.2016.02.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 02/12/2016] [Accepted: 02/25/2016] [Indexed: 11/26/2022]
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21
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Dương MT, Nguyễn NH, Trần TN, Tolba R, Staat M. Influence of refrigerated storage on tensile mechanical properties of porcine liver and spleen. Int Biomech 2015. [DOI: 10.1080/23335432.2015.1049295] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Schwartz D, Guleyupoglu B, Koya B, Stitzel JD, Gayzik FS. Development of a computationally efficient full human body finite element model. TRAFFIC INJURY PREVENTION 2015; 16 Suppl 1:S49-S56. [PMID: 26027975 DOI: 10.1080/15389588.2015.1021418] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
INTRODUCTION A simplified and computationally efficient human body finite element model is presented. The model complements the Global Human Body Models Consortium (GHBMC) detailed 50th percentile occupant (M50-O) by providing kinematic and kinetic data with a significantly reduced run time using the same body habitus. METHODS The simplified occupant model (M50-OS) was developed using the same source geometry as the M50-O. Though some meshed components were preserved, the total element count was reduced by remeshing, homogenizing, or in some cases omitting structures that are explicitly contained in the M50-O. Bones are included as rigid bodies, with the exception of the ribs, which are deformable but were remeshed to a coarser element density than the M50-O. Material models for all deformable components were drawn from the biomechanics literature. Kinematic joints were implemented at major articulations (shoulder, elbow, wrist, hip, knee, and ankle) with moment vs. angle relationships from the literature included for the knee and ankle. The brain of the detailed model was inserted within the skull of the simplified model, and kinematics and strain patterns are compared. RESULTS The M50-OS model has 11 contacts and 354,000 elements; in contrast, the M50-O model has 447 contacts and 2.2 million elements. The model can be repositioned without requiring simulation. Thirteen validation and robustness simulations were completed. This included denuded rib compression at 7 discrete sites, 5 rigid body impacts, and one sled simulation. Denuded tests showed a good match to the experimental data of force vs. deflection slopes. The frontal rigid chest impact simulation produced a peak force and deflection within the corridor of 4.63 kN and 31.2%, respectively. Similar results vs. experimental data (peak forces of 5.19 and 8.71 kN) were found for an abdominal bar impact and lateral sled test, respectively. A lateral plate impact at 12 m/s exhibited a peak of roughly 20 kN (due to stiff foam used around the shoulder) but a more biofidelic response immediately afterward, plateauing at 9 kN at 12 ms. Results from a frontal sled simulation showed that reaction forces and kinematic trends matched experimental results well. The robustness test demonstrated that peak femur loads were nearly identical to the M50-O model. Use of the detailed model brain within the simplified model demonstrated a paradigm for using the M50-OS to leverage aspects of the M50-O. Strain patterns for the 2 models showed consistent patterns but greater strains in the detailed model, with deviations thought to be the result of slightly different kinematics between models. The M50-OS with the deformable skull and brain exhibited a run time 4.75 faster than the M50-O on the same hardware. CONCLUSIONS The simplified GHBMC model is intended to complement rather than replace the detailed M50-O model. It exhibited, on average, a 35-fold reduction in run time for a set of rigid impacts. The model can be used in a modular fashion with the M50-O and more broadly can be used as a platform for parametric studies or studies focused on specific body regions.
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Affiliation(s)
- Doron Schwartz
- a Wake Forest University School of Medicine , Winston-Salem , North Carolina
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23
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Effects of pressure on the shear modulus, mass and thickness of the perfused porcine kidney. J Biomech 2015; 48:30-7. [DOI: 10.1016/j.jbiomech.2014.11.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 09/20/2014] [Accepted: 11/10/2014] [Indexed: 01/09/2023]
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Wex C, Arndt S, Stoll A, Bruns C, Kupriyanova Y. Isotropic incompressible hyperelastic models for modelling the mechanical behaviour of biological tissues: a review. ACTA ACUST UNITED AC 2015; 60:577-92. [DOI: 10.1515/bmt-2014-0146] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 05/07/2015] [Indexed: 11/15/2022]
Abstract
AbstractModelling the mechanical behaviour of biological tissues is of vital importance for clinical applications. It is necessary for surgery simulation, tissue engineering, finite element modelling of soft tissues, etc. The theory of linear elasticity is frequently used to characterise biological tissues; however, the theory of nonlinear elasticity using hyperelastic models, describes accurately the nonlinear tissue response under large strains. The aim of this study is to provide a review of constitutive equations based on the continuum mechanics approach for modelling the rate-independent mechanical behaviour of homogeneous, isotropic and incompressible biological materials. The hyperelastic approach postulates an existence of the strain energy function – a scalar function per unit reference volume, which relates the displacement of the tissue to their corresponding stress values. The most popular form of the strain energy functions as Neo-Hookean, Mooney-Rivlin, Ogden, Yeoh, Fung-Demiray, Veronda-Westmann, Arruda-Boyce, Gent and their modifications are described and discussed considering their ability to analytically characterise the mechanical behaviour of biological tissues. The review provides a complete and detailed analysis of the strain energy functions used for modelling the rate-independent mechanical behaviour of soft biological tissues such as liver, kidney, spleen, brain, breast, etc.
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25
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Effect of storage on tensile material properties of bovine liver. J Mech Behav Biomed Mater 2014; 29:339-49. [DOI: 10.1016/j.jmbbm.2013.09.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 09/18/2013] [Accepted: 09/22/2013] [Indexed: 11/17/2022]
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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.
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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
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Kemper AR, Santago AC, Stitzel JD, Sparks JL, Duma SM. Effect of Strain Rate on the Material Properties of Human Liver Parenchyma in Unconfined Compression. J Biomech Eng 2013; 135:104503-8. [DOI: 10.1115/1.4024821] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 06/17/2013] [Indexed: 12/21/2022]
Abstract
The liver is one of the most frequently injured organs in abdominal trauma. Although motor vehicle collisions are the most common cause of liver injuries, current anthropomorphic test devices are not equipped to predict the risk of sustaining abdominal organ injuries. Consequently, researchers rely on finite element models to assess the potential risk of injury to abdominal organs such as the liver. These models must be validated based on appropriate biomechanical data in order to accurately assess injury risk. This study presents a total of 36 uniaxial unconfined compression tests performed on fresh human liver parenchyma within 48 h of death. Each specimen was tested once to failure at one of four loading rates (0.012, 0.106, 1.036, and 10.708 s−1) in order to investigate the effects of loading rate on the compressive failure properties of human liver parenchyma. The results of this study showed that the response of human liver parenchyma is both nonlinear and rate dependent. Specifically, failure stress significantly increased with increased loading rate, while failure strain significantly decreased with increased loading rate. The failure stress and failure strain for all liver parenchyma specimens ranged from −38.9 kPa to −145.9 kPa and from −0.48 strain to −1.15 strain, respectively. Overall, this study provides novel biomechanical data that can be used in the development of rate dependent material models and the identification of tissue-level tolerance values, which are critical to the validation of finite element models used to assess injury risk.
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Affiliation(s)
| | | | | | | | - Stefan M. Duma
- Center for Injury Biomechanics, Virginia Tech—Wake Forest University, Blacksburg, VA 24061
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Helfenstein C, Gennisson JL, Tanter M, Beillas P. Internal kidney's behaviour during compressive loading using ultrafast echography. Comput Methods Biomech Biomed Engin 2013; 16 Suppl 1:200-1. [DOI: 10.1080/10255842.2013.815911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Nicolle S, Noguer L, Palierne JF. Shear mechanical properties of the porcine pancreas: experiment and analytical modelling. J Mech Behav Biomed Mater 2013; 26:90-7. [PMID: 23820244 DOI: 10.1016/j.jmbbm.2013.05.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 05/16/2013] [Accepted: 05/27/2013] [Indexed: 12/31/2022]
Abstract
We provide the first account of the shear mechanical properties of porcine pancreas using a rheometer both in linear oscillatory tests and in constant strain-rate tests reaching the non-linear sub-failure regime. Our results show that pancreas has a low and weakly frequency-dependent dynamic modulus and experiences a noticeable strain-hardening beyond 20% strain. In both linear and non-linear regime, the viscoelastic behaviour of porcine pancreas follows a four-parameter bi-power model that has been validated on kidney, liver and spleen. Among the four solid organs of the abdomen, pancreas proves to be the most compliant and the most viscous one.
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Affiliation(s)
- S Nicolle
- Université de Lyon, F-69622, Lyon, France.
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Lu YC, Untaroiu CD. Effect of storage methods on indentation-based material properties of abdominal organs. Proc Inst Mech Eng H 2012; 227:293-301. [DOI: 10.1177/0954411912468558] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
To investigate the possible changes in material properties of cadaveric abdominal organs due to the preservation methods, the indentation data obtained from porcine abdominal organs (kidney, liver, and spleen) preserved by cooling and freezing are analyzed statistically in this study. Indentation tests were first conducted on fresh specimens. One half of the specimens of each organ were then frozen (preserved at −12 °C), and the other half of the specimens were cooled (preserved at 4 °C). All preserved specimens were retested after 20 days. Force and displacement data recorded during indentation were analyzed using a quasi-linear viscoelastic model. The results show that both cooling and freezing storage increased the kidney stiffness. In contrast, both storage methods decreased the stiffness of the spleen specimens. While cooling increased the liver stiffness, no significant changes of the instantaneous elastic response were observed in the liver specimens preserved by freezing. The liver and spleen’s reduced relaxation responses and the liver’s instantaneous elastic response were significantly different when comparing between cooling and freezing effects after 20 days of preservation. This study showed that both cooling and freezing storage methods significantly changed the material properties of abdominal organs, especially the instantaneous elastic response. More research is needed in investigating the effect of preservation on failure properties and mechanical properties under large deformation.
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Affiliation(s)
- Yuan-Chiao Lu
- Virginia Tech and Wake Forest University School of Biomedical Engineering and Sciences, Center for Injury Biomechanics, Virginia Tech, Blacksburg, VA, USA
| | - Costin D Untaroiu
- Virginia Tech and Wake Forest University School of Biomedical Engineering and Sciences, Center for Injury Biomechanics, Virginia Tech, Blacksburg, VA, USA
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Lateral Impact Validation of a Geometrically Accurate Full Body Finite Element Model for Blunt Injury Prediction. Ann Biomed Eng 2012; 41:497-512. [DOI: 10.1007/s10439-012-0684-3] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 10/22/2012] [Indexed: 11/25/2022]
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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.
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Affiliation(s)
- Sagar Umale
- Institut de Mécanique des Fluides et des Solides, UNISTRA-CNRS, Strasbourg, France
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External Landmark, Body Surface, and Volume Data of a Mid-Sized Male in Seated and Standing Postures. Ann Biomed Eng 2012; 40:2019-32. [DOI: 10.1007/s10439-012-0546-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 03/05/2012] [Indexed: 12/15/2022]
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