scholarly journals Mathematical model and computational scheme for multi-phase modeling of cellular population and microenvironmental dynamics in soft tissue

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260108
Author(s):  
Gregory Baramidze ◽  
Victoria Baramidze ◽  
Ying Xu
Keyword(s):  
Soft Tissue ◽  
Interstitial Fluid ◽  
Soft Tissues ◽  
Constitutive Relations ◽  
State Variables ◽  
Advective Flux ◽  
Cellular Population ◽  
Multi Phase ◽  
Chemical Fields ◽  
Multiple Chemical

In this paper we introduce a system of partial differential equations that is capable of modeling a variety of dynamic processes in soft tissue cellular populations and their microenvironments. The model is designed to be general enough to simulate such processes as tissue regeneration, tumor growth, immune response, and many more. It also has built-in flexibility to include multiple chemical fields and/or sub-populations of cells, interstitial fluid and/or extracellular matrix. The model is derived from the conservation laws for mass and linear momentum and therefore can be classified as a continuum multi-phase model. A careful choice of state variables provides stability in solving the system of discretized equations defining advective flux terms. A concept of deviation from normal allows us to use simplified constitutive relations for stresses. We also present an algorithm for computing numerical approximations to the solutions of the system and discuss properties of these approximations. We demonstrate several examples of applications of the model. Numerical simulations show a significant potential of the model for simulating a variety of processes in soft tissues.

scholarly journals A Reactive Inelasticity Theoretical Framework for Modeling Viscoelasticity, Plastic Deformation, and Damage in Fibrous Soft Tissue

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Babak N. Safa ◽  
Michael H. Santare ◽  
Dawn M. Elliott
Keyword(s):  
Plastic Deformation ◽  
Soft Tissues ◽  
Constitutive Relations ◽  
Deformation Gradient ◽  
Theoretical Framework ◽  
Extracellular Proteins ◽  
External Loading ◽  
High Water Content ◽  
State Variables ◽  
Mechanical Behaviors

Fibrous soft tissues are biopolymeric materials that are made of extracellular proteins, such as different types of collagen and proteoglycans, and have a high water content. These tissues have nonlinear, anisotropic, and inelastic mechanical behaviors that are often categorized into viscoelastic behavior, plastic deformation, and damage. While tissue's elastic and viscoelastic mechanical properties have been measured for decades, there is no comprehensive theoretical framework for modeling inelastic behaviors of these tissues that is based on their structure. To model the three major inelastic mechanical behaviors of tissue's fibrous matrix, we formulated a structurally inspired continuum mechanics framework based on the energy of molecular bonds that break and reform in response to external loading (reactive bonds). In this framework, we employed the theory of internal state variables (ISV) and kinetics of molecular bonds. The number fraction of bonds, their reference deformation gradient, and damage parameter were used as state variables that allowed for consistent modeling of all three of the inelastic behaviors of tissue by using the same sets of constitutive relations. Several numerical examples are provided that address practical problems in tissue mechanics, including the difference between plastic deformation and damage. This model can be used to identify relationships between tissue's mechanical response to external loading and its biopolymeric structure.

scholarly journals A Reactive Inelasticity Theoretical Framework for modeling Viscoelasticity, Plastic Deformation, and damage in Soft Tissue

2018 ◽  
Author(s):  
Babak N. Safa ◽  
Michael H. Santare ◽  
Dawn M. Elliott
Keyword(s):  
Plastic Deformation ◽  
Soft Tissue ◽  
Internal State ◽  
Constitutive Relations ◽  
Deformation Gradient ◽  
Theoretical Framework ◽  
External Loading ◽  
State Variables ◽  
Mechanical Behaviors ◽  
Internal State Variables

AbstractSoft tissues are biopolymeric materials, primarily made of collagen and water. These tissues have non-linear, anisotropic, and inelastic mechanical behaviors that are often categorized into viscoelastic behavior, plastic deformation, and damage. While tissue’s elastic and viscoelastic mechanical properties have been measured for decades, there is no comprehensive theoretical framework for modeling inelastic behaviors of these tissues that is based on their structure. To model the three major inelastic mechanical behaviors of soft tissue we formulated a structurally inspired continuum mechanics framework based on the energy of molecular bonds that break and reform in response to external loading (reactive bonds). In this framework, we employed the theory of internal state variables and kinetics of molecular bonds. The number fraction of bonds, their reference deformation gradient, and damage parameter were used as internal state variables that allowed for consistent modeling of all three of the inelastic behaviors of tissue by using the same sets of constitutive relations. Several numerical examples are provided that address practical problems in tissue mechanics, including the difference between plastic deformation and damage. This model can be used to identify relationships between tissue’s mechanical response to external loading and its biopolymeric structure.

Biphasic Poroviscoelastic Behavior of Hydrated Biological Soft Tissue

1999 ◽  
Vol 66 (2) ◽  
pp. 528-535 ◽  
Author(s):  
J.-K. Suh ◽  
M. R. DiSilvestro
Keyword(s):  
Fluid Flow ◽  
Soft Tissue ◽  
Interstitial Fluid ◽  
Soft Tissues ◽  
Soil Mechanics ◽  
Viscoelastic Behavior ◽  
Porous Matrix ◽  
Interstitial Fluid Flow ◽  
Poroelastic Theory ◽  
Biological Soft Tissue

Hydrated biological soft tissue consists of a porous extracellular matrix (ECM) and an interstitial fluid. The poroelastic theory (Biot, 1962), which was originally developed for soil mechanics, has been widely used for mathematical modeling of such hydrated biological tissue. This theory assumes that the ECM is incompressible and purely elastic, and that the interstitial fluid is incompressible and inviscid. The overall viscoelasticity of the tissue is expressed as a result of the frictional interaction between the elastic porous matrix and the interstitial fluid. The poroelastic theory, also known as the biphasic theory (Mow et al., 1980) in the biomechanics field, has served well over the past 20 years as an excellent modeling tool for the interstitial fluid flow-dependent viscoelastic response of hydrated soft tissue. It has been demonstrated that hydrated soft tissue also possesses a significant intrinsic viscoelasticity, independent of the interstitial fluid flow. The biphasic poroviscoelastic (BPVE) theory, which was first introduced by Mak (1986a and 1986b), incorporates a viscoelastic relaxation function into the effective solid stress of the poroelastic theory thus accounting for both intrinsic fluid flow-independent and fluid flow-dependent viscoelasticity. The objective of the present study is to investigate the biphasic poroviscoelastic characteristics of hydrated soft tissue, with an emphasis on the relative contribution of fluid flow-dependent and fluid flow-independent viscoelasticity to the overall viscoelastic behavior of soft tissues.

Imaging Features of Primary Tumors of the Hand

2020 ◽  
Vol 16 ◽  
Author(s):  
Filippo Boriani ◽  
Edoardo Raposio ◽  
Costantino Errani
Keyword(s):  
Soft Tissue ◽  
Soft Tissues ◽  
Epithelioid Sarcoma ◽  
Case Series ◽  
Malignant Neoplasm ◽  
Benign Tumors ◽  
Imaging Features ◽  
Primary Tumors ◽  
Therapeutic Decisions ◽  
Tumors Of The Hand

: Musculoskeletal tumors of the hand are a rare entity and are divided into skeletal and soft tissue tumors. Either category comprises benign and malignant or even intermediate tumors. Basic radiology allows an optimal resolution of bone and related soft tissue areas, ultrasound and more sophisticated radiologic tools such as scintigraphy, CT and MRI allow a more accurate evaluation of tumor extent. Enchondroma is the most common benign tumor affecting bone, whereas chondrosarcoma is the most commonly represented malignant neoplasm localized to hand bones. In the soft tissues ganglions are the most common benign tumors and epithelioid sarcoma is the most frequently represented malignant tumor targeting hand soft tissues. The knowledge regarding diagnostic and therapeutic management of these tumors is often deriving from small case series, retrospective studies or even case reports. Evidences from prospective studies or controlled trials are limited and for this lack of clear and supported evidences data from the medical literature on the topic are controversial, in terms of demographics, clinical presentation, diagnosis prognosis and therapy.The correct recognition of the specific subtype and extension of the tumor through first line and second line radiology is essential for the surgeon, in order to effectively direct the therapeutic decisions.

scholarly journals Developing a Quantifying Device for Soft Tissue Material Prop-Erties around Lumbar Spines

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 67
Author(s):  
Song Joo Lee ◽  
Yong-Eun Cho ◽  
Kyung-Hyun Kim ◽  
Deukhee Lee
Keyword(s):  
Lumbar Spine ◽  
Soft Tissue ◽  
Young’S Modulus ◽  
Viscoelastic Properties ◽  
Soft Tissues ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress And Strain ◽  
Commercial Device ◽  
Tissue Material

Knowing the material properties of the musculoskeletal soft tissue could be important to develop rehabilitation therapy and surgical procedures. However, there is a lack of devices and information on the viscoelastic properties of soft tissues around the lumbar spine. The goal of this study was to develop a portable quantifying device for providing strain and stress curves of muscles and ligaments around the lumbar spine at various stretching speeds. Each sample was conditioned and applied for 20 repeatable cyclic 5 mm stretch-and-relax trials in the direction and perpendicular direction of the fiber at 2, 3 and 5 mm/s. Our device successfully provided the stress and strain curve of the samples and our results showed that there were significant effects of speed on the young’s modulus of the samples (p < 0.05). Compared to the expensive commercial device, our lower-cost device provided comparable stress and strain curves of the sample. Based on our device and findings, various sizes of samples can be measured and viscoelastic properties of the soft tissues can be obtained. Our portable device and approach can help to investigate young’s modulus of musculoskeletal soft tissues conveniently, and can be a basis for developing a material testing device in a surgical room or various lab environments.

scholarly journals Quantification of assembly forces during creation of head-neck taper junction considering soft tissue bearing: a biomechanical study

Arthroplasty ◽  
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Toni Wendler ◽  
Torsten Prietzel ◽  
Robert Möbius ◽  
Jean-Pierre Fischer ◽  
Andreas Roth ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Work Experience ◽  
Soft Tissues ◽  
Force Sensor ◽  
Biomechanical Study ◽  
Measuring System ◽  
Wide Range ◽  
Head Neck

Abstract Background All current total hip arthroplasty (THA) systems are modular in design. Only during the operation femoral head and stem get connected by a Morse taper junction. The junction is realized by hammer blows from the surgeon. Decisive for the junction strength is the maximum force acting once in the direction of the neck axis, which is mainly influenced by the applied impulse and surrounding soft tissues. This leads to large differences in assembly forces between the surgeries. This study aimed to quantify the assembly forces of different surgeons under influence of surrounding soft tissue. Methods First, a measuring system, consisting of a prosthesis and a hammer, was developed. Both components are equipped with a piezoelectric force sensor. Initially, in situ experiments on human cadavers were carried out using this system in order to determine the actual assembly forces and to characterize the influence of human soft tissues. Afterwards, an in vitro model in the form of an artificial femur (Sawbones Europe AB, Malmo, Sweden) with implanted measuring stem embedded in gelatine was developed. The gelatine mixture was chosen in such a way that assembly forces applied to the model corresponded to those in situ. A study involving 31 surgeons was carried out on the aforementioned in vitro model, in which the assembly forces were determined. Results A model was developed, with the influence of human soft tissues being taken into account. The assembly forces measured on the in vitro model were, on average, 2037.2 N ± 724.9 N, ranging from 822.5 N to 3835.2 N. The comparison among the surgeons showed no significant differences in sex (P = 0.09), work experience (P = 0.71) and number of THAs performed per year (P = 0.69). Conclusions All measured assembly forces were below 4 kN, which is recommended in the literature. This could lead to increased corrosion following fretting in the head-neck interface. In addition, there was a very wide range of assembly forces among the surgeons, although other influencing factors such as different implant sizes or materials were not taken into account. To ensure optimal assembly force, the impaction should be standardized, e.g., by using an appropriate surgical instrument.

scholarly journals Imaging of Joint and Soft Tissue Involvement in Systemic Lupus Erythematosus

2021 ◽  
Vol 23 (9) ◽  
Author(s):  
Andrea Di Matteo ◽  
Gianluca Smerilli ◽  
Edoardo Cipolletta ◽  
Fausto Salaffi ◽  
Rossella De Angelis ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Soft Tissue ◽  
Lupus Erythematosus ◽  
Structural Damage ◽  
Structural Changes ◽  
Soft Tissues ◽  
Imaging Techniques ◽  
Joint Involvement ◽  
Systemic Lupus ◽  
Muscle Involvement

Abstract Purpose of Review To highlight the potential uses and applications of imaging in the assessment of the most common and relevant musculoskeletal (MSK) manifestations in systemic lupus erythematosus (SLE). Recent Findings Ultrasound (US) and magnetic resonance imaging (MRI) are accurate and sensitive in the assessment of inflammation and structural damage at the joint and soft tissue structures in patients with SLE. The US is particularly helpful for the detection of joint and/or tendon inflammation in patients with arthralgia but without clinical synovitis, and for the early identification of bone erosions. MRI plays a key role in the early diagnosis of osteonecrosis and in the assessment of muscle involvement (i.e., myositis and myopathy). Conventional radiography (CR) remains the traditional gold standard for the evaluation of structural damage in patients with joint involvement, and for the study of bone pathology. The diagnostic value of CR is affected by the poor sensitivity in demonstrating early structural changes at joint and soft tissue level. Computed tomography allows a detailed evaluation of bone damage. However, the inability to distinguish different soft tissues and the need for ionizing radiation limit its use to selected clinical circumstances. Nuclear imaging techniques are valuable resources in patients with suspected bone infection (i.e., osteomyelitis), especially when MRI is contraindicated. Finally, dual energy X-ray absorptiometry represents the imaging mainstay for the assessment and monitoring of bone status in patients with or at-risk of osteoporosis. Summary Imaging provides relevant and valuable information in the assessment of MSK involvement in SLE.

scholarly journals Micro-CT imaging of Thiel-embalmed and iodine-stained human temporal bone for 3D modeling

2021 ◽  
Vol 50 (1) ◽  
Author(s):  
Sebastian Halm ◽  
David Haberthür ◽  
Elisabeth Eppler ◽  
Valentin Djonov ◽  
Andreas Arnold
Keyword(s):  
Soft Tissue ◽  
Temporal Bone ◽  
Middle Ear ◽  
3D Modeling ◽  
Soft Tissues ◽  
Ct Imaging ◽  
Micro Ct ◽  
Data Set ◽  
Iodine Staining ◽  
Tissue Structures

Abstract Introduction This pilot study explores whether a human Thiel-embalmed temporal bone is suitable for generating an accurate and complete data set with micro-computed tomography (micro-CT) and whether solid iodine-staining improves visualization and facilitates segmentation of middle ear structures. Methods A temporal bone was used to verify the accuracy of the imaging by first digitally measuring the stapes on the tomography images and then physically under the microscope after removal from the temporal bone. All measurements were compared with literature values. The contralateral temporal bone was used to evaluate segmentation and three-dimensional (3D) modeling after iodine staining and micro-CT scanning. Results The digital and physical stapes measurements differed by 0.01–0.17 mm or 1–19%, respectively, but correlated well with the literature values. Soft tissue structures were visible in the unstained scan. However, iodine staining increased the contrast-to-noise ratio by a factor of 3.7 on average. The 3D model depicts all ossicles and soft tissue structures in detail, including the chorda tympani, which was not visible in the unstained scan. Conclusions Micro-CT imaging of a Thiel-embalmed temporal bone accurately represented the entire anatomy. Iodine staining considerably increased the contrast of soft tissues, simplified segmentation and enabled detailed 3D modeling of the middle ear.

Orthodontic Pre Grafting Closure of Large Alveolar Bony and Soft Tissue Gaps: A Novel Nonsurgical Protraction of the Lesser Segments in Growing Patients With Cleft Lip and Palate

2021 ◽  
pp. 105566562110076
Author(s):  
Maria Costanza Meazzini ◽  
Noah Cohen ◽  
Valeria Marinella Augusta Battista ◽  
Cristina Incorvati ◽  
Federico Biglioli ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Surgical Procedures ◽  
Efficient Method ◽  
Bone Grafting ◽  
Cleft Lip ◽  
Soft Tissues ◽  
Cleft Lip And Palate ◽  
Face Mask ◽  
Younger Patients ◽  
Good Healing

Background: Closure of wide alveolar clefts with large soft tissue gaps and reconstruction of the dentoalveolar defect are challenging for the surgeon. Some authors successfully used interdental segmental distraction, which requires an additional surgical procedure. Objective: This study evaluates the effectiveness of tooth borne devices utilized to orthopedically advance the lesser segments, with a complete approximation of the soft tissue of the alveolar stumps, allowing traditional simultaneous soft tissue closure and bone grafting, and avoiding the need for supplementary surgery. Methods: Eight growing patients, 2 with unilateral complete cleft lip and palate (UCLP) and 6 with bilateral complete cleft lip and palate (BCLP), with large soft tissue and bony alveolar defects prior to bone grafting were prospectively selected. A banded rapid palatal expander (RPE) in BCLP and a modified RPE in UCLP combined with protraction face mask in younger patients or a modified Alt-Ramec in patients older than 12 years were applied. Radiographic and photographic records were available at T0, at the end of protraction (T1) and at least 1 year after bone grafting (T2). Results: Patients with large gaps showed a significant reduction in the bony cleft area and approximation of the soft tissues at T1. All patients received bone grafting with good healing and ossification at T2. Conclusion: In growing patients with UCLP and BCLP with large gaps, presurgical orthodontic protraction seems to be an efficient method to reduce the cleft defect, minimizing the risk of post grafting fistulas, reducing the need for supplementary surgical procedures.

scholarly journals Accuracy and Reliability of Soft Tissue Landmarks Using Three-Dimensional Imaging in Comparison With Two-Dimensional Cephalometrics: A Systematic Review

2020 ◽  
Vol 54 (4) ◽  
pp. 289-296
Author(s):  
Adeeba Ali ◽  
Anil K. Chandna ◽  
Anshul Munjal
Keyword(s):  
Systematic Review ◽  
Soft Tissue ◽  
3D Imaging ◽  
Soft Tissues ◽  
Three Dimensional ◽  
Database Search ◽  
Cochrane Library ◽  
Two Dimensional ◽  
Imaging Tool ◽  
Electronic Database Search

Background: Concerns about the accuracy and reliability of soft tissue landmarks using two-dimensional (2D) and three-dimensional (3D) imaging. Objective: The aim of the systematic review is to estimate accuracy and reliability of soft tissue landmarks with 2D imaging and 3D imaging for orthodontic diagnosis planning and treatment planning purposes. Data Sources: Electronic database search was performed in MEDLINE via PubMed, Embase via embase.com, and the Cochrane library website. Selection Criteria: The data were extracted according to two protocols based on Centre for Evidence-Based Medicine (CEBM) critical appraisal tools. Next, levels of evidence were categorized into three groups: low, medium, and high. Data Synthesis: Fifty-five publications were found through database search strategies. A total of nine publications were included in this review. Conclusion According to the available literature, 3D imaging modalities were more accurate and reliable as compared to 2D modalities. Cone beam computed tomography (CBCT) was considered the most reliable imaging tool for soft tissues.

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