scholarly journals Modelling of Soft Connective Tissues to Investigate Female Pelvic Floor Dysfunctions

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Aroj Bhattarai ◽  
Manfred Staat
Keyword(s):  
Pelvic Floor ◽  
Soft Tissues ◽  
Volume Fraction ◽  
Collagen Fibre ◽  
Mixture Theory ◽  
Valsalva Manoeuvre ◽  
Connective Tissues ◽  
Pelvic Organs ◽  
Urethrovesical Junction ◽  
Tip Test

After menopause, decreased levels of estrogen and progesterone remodel the collagen of the soft tissues thereby reducing their stiffness. Stress urinary incontinence is associated with involuntary urine leakage due to pathological movement of the pelvic organs resulting from lax suspension system, fasciae, and ligaments. This study compares the changes in the orientation and position of the female pelvic organs due to weakened fasciae, ligaments, and their combined laxity. A mixture theory weighted by respective volume fraction of elastin-collagen fibre compound (5%), adipose tissue (85%), and smooth muscle (5%) is adopted to characterize the mechanical behaviour of the fascia. The load carrying response (other than the functional response to the pelvic organs) of each fascia component, pelvic organs, muscles, and ligaments are assumed to be isotropic, hyperelastic, and incompressible. Finite element simulations are conducted during Valsalva manoeuvre with weakened tissues modelled by reduced tissue stiffness. A significant dislocation of the urethrovesical junction is observed due to weakness of the fascia (13.89 mm) compared to the ligaments (5.47 mm). The dynamics of the pelvic floor observed in this study during Valsalva manoeuvre is associated with urethral-bladder hypermobility, greater levator plate angulation, and positive Q-tip test which are observed in incontinent females.

MRI urethrovesical junction mobility is associated with global pelvic floor laxity in female stress incontinence

2007 ◽  
Vol 86 (10) ◽  
pp. 1243-1250 ◽  
Author(s):  
Yan Ansquer ◽  
Pedro Fernandez ◽  
Sabine Aimot ◽  
Malika Bennis ◽  
Laurence Salomon ◽  
...  
Keyword(s):  
Pelvic Floor ◽  
Stress Incontinence ◽  
Female Stress Incontinence ◽  
Urethrovesical Junction

Some notes on a volume fraction mixture theory and a comparison with the kinetic theory of gases

1991 ◽  
Vol 29 (5) ◽  
pp. 561-573 ◽  
Author(s):  
A.C. Hansen ◽  
R.L. Crane ◽  
M.H. Damson ◽  
R.P. Donovan ◽  
D.T. Horning ◽  
...  
Keyword(s):  
Kinetic Theory ◽  
Volume Fraction ◽  
Mixture Theory ◽  
Kinetic Theory Of Gases ◽  
Fraction Mixture

QUASI-LINEAR VISCOELASTIC MODELLING OF UNCURED PREPREGS UNDER COMPACTION

2021 ◽  
Author(s):  
SIDDHESH S. KULKARNI ◽  
KAMRAN A. KHAN ◽  
REHAN UMER
Keyword(s):  
Stress Relaxation ◽  
Relaxation Function ◽  
Soft Tissues ◽  
Volume Fraction ◽  
Time Dependent ◽  
Strain History ◽  
Manufacturing Processes ◽  
Fiber Volume ◽  
Consolidation Process ◽  
Thermoset Resin

Reinforcement compaction sometimes referred as consolidation process and is one of the key steps in various composite manufacturing processes such as autoclave and out-of-autoclave processing. The prepregs consist of semi-cured thermoset resin system impregnating the fibers. hence, the prepreg shows strong viscoelastic compaction response, which strongly depends on compaction speed and stress relaxation. modeling of time-dependent response is of utmost importance to understand the behavior of prepregs during different stages of composites manufacturing processes. The quasilinear viscoelastic (QLV) theory has been extensively used for the modeling of viscoelastic response of soft tissues in biomedical applications. In QLV approach, the stress relaxation can be expressed in terms of the nonlinear elastic function and the reduced relaxation function. The constitutive equation can be represented by a convolution integral of the nonlinear strain history, and reduced relaxation function. This study adopted a quasilinear viscoelastic modeling approach to describe the time dependent behavior of uncured-prepregs under compression. The model was modified to account for the compaction behavior of the prepreg under a compressive load. The deformation behavior of the prepreg is usually characterized by the fiber volume fraction, V . In this study, the material used was a 2/2 Twill weave glass prepreg (M26T) supplied by Hexcel® Industries USA. We performed a compaction experiment of the uncured prepreg at room temperature at different displacement rate and subsequent relaxation to describe the viscoelastic behavior of the prepreg. The model parameter calibration was performed using the trust-region-reflective algorithm in matlab to a selected number of test data. The calibrated model was then used to predict the rate dependent compaction and relaxation response of prepregs for different fiber volume fractions and strain rates.

Implementation of Finite Deformation Triphasic Modeling in the Finite Element Code FEBio

2012 ◽  
Author(s):  
Gerard A. Ateshian ◽  
Steve Maas ◽  
Jeffrey A. Weiss
Keyword(s):  
Soft Tissues ◽  
Mixture Theory ◽  
Solid Matrix ◽  
Osmotic Swelling ◽  
Solute Content ◽  
Counter Ions ◽  
The Matrix ◽  
Triphasic Theory ◽  
Ion Species ◽  
And Diffusion

Many biological soft tissues exhibit a charged solid matrix, most often due to the presence of proteoglycans enmeshed within the matrix. The predominant solute content of the interstitial fluid of these tissues consists of the monovalent counter-ions Na+ and Cl−. The electrical interactions between the mobile ion species and fixed charge density of the solid matrix produces an array of mechano-electrochemical effects, including Donnan osmotic swelling, and streaming and diffusion potentials and currents. These phenomena have been successfully modeled by the triphasic theory of Lai et al. [1], which is based on the framework of mixture theory [2]. Other similar frameworks have also been proposed [3, 4]. The equations of triphasic theory are nonlinear, even in the range of infinitesimal strains. Therefore, numerical schemes are generally needed to solve all but the simplest problems using this framework.

Tensile Properties of the Swine Cardinal Ligament

2013 ◽  
Author(s):  
Frances M. Davis ◽  
Ting Tan ◽  
Suzanne Nicewonder ◽  
Raffaella De Vita
Keyword(s):  
Public Health ◽  
United States ◽  
Pelvic Floor Disorders ◽  
The United States ◽  
Pelvic Organ ◽  
Health Concern ◽  
Adult Women ◽  
Public Health Concern ◽  
Connective Tissues ◽  
Pelvic Organs

Pelvic floor disorders such as urinary incontinence, fecal incontinence, and pelvic organ prolapse represent a major public health concern in the United States affecting one third of adult women [1]. These disorders are determined by structural and mechanical alterations of the pelvic organs, their supporting muscles and connective tissues that occur mainly during pregnancy, vaginal delivery, and aging [1].

scholarly journals Vestibular Anatomic Localization of Pain Sensitivity in Women with Insertional Dyspareunia: A Different Approach to Address the Variability of Painful Intercourse

2020 ◽  
Vol 9 (7) ◽  
pp. 2023
Author(s):  
Ahinoam Lev-Sagie ◽  
Osnat Wertman ◽  
Yoav Lavee ◽  
Michal Granot
Keyword(s):  
Pelvic Floor ◽  
Hormonal Contraception ◽  
Pelvic Floor Muscles ◽  
Pain Experience ◽  
Pain Hypersensitivity ◽  
Contraception Use ◽  
Painful Intercourse ◽  
Tip Test ◽  
Anatomic Localization

The pathophysiology underlying painful intercourse is challenging due to variability in manifestations of vulvar pain hypersensitivity. This study aimed to address whether the anatomic location of vestibular-provoked pain is associated with specific, possible causes for insertional dyspareunia. Women (n = 113) were assessed for “anterior” and “posterior” provoked vestibular pain based on vestibular tenderness location evoked by a Q-tip test. Pain evoked during vaginal intercourse, pain evoked by deep muscle palpation, and the severity of pelvic floor muscles hypertonicity were assessed. The role of potential confounders (vestibular atrophy, umbilical pain hypersensitivity, hyper-tonus of pelvic floor muscles and presence of a constricting hymenal-ring) was analyzed to define whether distinctive subgroups exist. Q-tip stimulation provoked posterior vestibular tenderness in all participants (6.20 ± 1.9). However, 41 patients also demonstrated anterior vestibular pain hypersensitivity (5.24 ± 1.5). This group (circumferential vestibular tenderness), presented with either vestibular atrophy associated with hormonal contraception use (n = 21), or augmented tactile umbilical-hypersensitivity (n = 20). The posterior-only vestibular tenderness group included either women with a constricting hymenal-ring (n = 37) or with pelvic floor hypertonicity (n = 35). Interestingly, pain evoked during intercourse did not differ between groups. Linear regression analyses revealed augmented coital pain experience, umbilical-hypersensitivity and vestibular atrophy predicted enhanced pain hypersensitivity evoked at the anterior, but not at the posterior vestibule (R = 0.497, p < 0.001). Distinguishing tactile hypersensitivity in anterior and posterior vestibule and recognition of additional nociceptive markers can lead to clinical subgrouping.

scholarly journals Vertical flow of a multiphase mixture in a channel

2001 ◽  
Vol 6 (6) ◽  
pp. 505-526 ◽  
Author(s):  
Mehrdad Massoudi ◽  
C. Lakshmana Rao
Keyword(s):  
Volume Fraction ◽  
Constitutive Relations ◽  
Mixture Theory ◽  
Interaction Force ◽  
Solid Particles ◽  
Vertical Flow ◽  
Dimensionless Numbers ◽  
Dimensionless Velocity ◽  
Multiphase Mixture ◽  
Linear Boundary Value Problem

The flow of a multiphase mixture consisting of a viscous fluid and solid particles between two vertical plates is studied. The theory of interacting continua or mixture theory is used. Constitutive relations for the stress tensor of the granular materials and the interaction force are presented and discussed. The flow of interest is an ideal one where we assume the flow to be steady and fully developed; the mixture is flowing between two long vertical plates. The non-linear boundary value problem is solved numerically, and the results are presented for the dimensionless velocity profiles and the volume fraction as functions of various dimensionless numbers.

scholarly journals Pelvic floor and sexual male dysfunction

2013 ◽  
Vol 85 (1) ◽  
pp. 1 ◽  
Author(s):  
Antonella Pischedda ◽  
Ferdinando Fusco ◽  
Andrea Curreli ◽  
Giovanni Grimaldi ◽  
Furio Pirozzi Farina
Keyword(s):  
Quality Of Life ◽  
Pelvic Floor ◽  
Daily Life ◽  
Pelvic Floor Dysfunction ◽  
Urinary Continence ◽  
Pelvic Organs ◽  
Muscle Hypotonia ◽  
Pelvic Statics ◽  
Anal Area

The pelvic floor is a complex multifunctional structure that corresponds to the genito- urinary-anal area and consists of muscle and connective tissue. It supports the urinary, fecal, sexual and reproductive functions and pelvic statics. The symptoms caused by pelvic floor dysfunction often affect the quality of life of those who are afflicted, worsening significantly more aspects of daily life. In fact, in addition to providing support to the pelvic organs, the deep floor muscles support urinary continence and intestinal emptying whereas the superficial floor muscles are involved in the mechanism of erection and ejaculation. So, conditions of muscle hypotonia or hypertonicity may affect the efficiency of the pelvic floor, altering both the functionality of the deep and superficial floor muscles. In this evolution of knowledge it is possible imagine how the rehabilitation techniques of pelvic floor muscles, if altered and able to support a voiding or evacuative or sexual dysfunction, may have a role in improving the health and the quality of life.

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