The Effect of Pubococcygeus Muscle Avulsion on the Anterior Vaginal Wall Support: A Biomechanical 3D Finite Element Modeling Study

2012 ◽  
Author(s):  
Luyun Chen ◽  
James A. Ashton-Miller ◽  
John O. L. DeLancey
Keyword(s):  
Finite Element ◽  
Levator Ani ◽  
Element Model ◽  
Pelvic Organ ◽  
Vaginal Wall ◽  
Anterior Vaginal Wall ◽  
Biomechanical Analysis ◽  
Pubic Bone ◽  
Levator Ani Muscle ◽  
3D Finite Element

Levator ani muscle defects are common in women after vaginal birth and have been associated with the development of pelvic organ prolapse (Kearney et al 2006, DeLancey et al 2007, and Dietz and Lanzarone 2005). Sometimes there is a loss of muscle substance but the overall shape of the muscle remains intact. In other instances, gross distortion of the muscle origin occurs (Huebner et al. 2008) presumably due to avulsion of muscle from the pubic bone. Theoretical biomechanical modeling work has showed that even with intact pubic origin, weakening of levator ani muscle leads to the development of cystocele (Chen et al, 2009). The biomechanical effects of avulsion of the pubic origin of the pubococcygeal muscle have not been fully explored. The objective of this study if to use a finite element model to perform a biomechanical analysis of how pubococcygeus muscle avulsion affects the descent of the anterior vaginal wall during a Valsalva.

Biomechanical Characterization of Sheep Vaginal Wall Tissue: A Potential Application in Human Pelvic Floor Disorders

2012 ◽  
Author(s):  
Sourav S. Patnaik ◽  
Benjamin Weed ◽  
Ali Borazjani ◽  
Robbin Bertucci ◽  
Mark Begonia ◽  
...  
Keyword(s):  
Levator Ani ◽  
Pelvic Organ ◽  
Vaginal Wall ◽  
Levator Ani Muscle ◽  
Social Psychological ◽  
Psychological Issues ◽  
Exact Etiology ◽  
History Of

Pelvic Organ Prolapse (POP) is a leading women’s health issue affecting a significant portion of the population and has been recently coined as a “silent epidemic”. POP leads to a considerable reduction in women’s quality of life and can cause chronic pelvic pain, sexual dysfunction, and social/psychological issues. The lifetime risk for having surgery for POP is approximately 11% with 200,000 POP procedures performed each year in USA, with an annual direct cost of over $1000 million. Exact etiology of POP is unclear, but it is understood that POP is multi-factorial in nature. Risk factors for POP include increasing age, obesity, multiple vaginal births, gravidity, history of hysterectomy, smoking, chronic cough conditions, frequent heavy lifting, and some genetic factors. POP results due to loss or damage of structural supports that support the pelvic organs (i.e. rectum, bowel, bladder, etc). Vaginal wall prolapse (anterior and posterior) is the most common presentation. This can result from weakening of the levator ani muscle and other connective tissue structures which not only control the mechanical function, but also help support neurological and anatomical function[1].

scholarly journals The construction of the scoliosis 3D finite element model and the biomechanical analysis of PVCR orthopaedy

2020 ◽  
Vol 27 (2) ◽  
pp. 695-700 ◽  
Author(s):  
Xuanhuang Chen ◽  
Hanhua Cai ◽  
Guodong Zhang ◽  
Feng Zheng ◽  
Changfu Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Biomechanical Analysis ◽  
3D Finite Element ◽  
3D Finite Element Model

scholarly journals Finite element model focused on stress distribution in the levator ani muscle during vaginal delivery

2016 ◽  
Vol 28 (2) ◽  
pp. 275-284 ◽  
Author(s):  
Ladislav Krofta ◽  
Linda Havelková ◽  
Iva Urbánková ◽  
Michal Krčmář ◽  
Luděk Hynčík ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Finite Element Model ◽  
Vaginal Delivery ◽  
Levator Ani ◽  
Element Model ◽  
Levator Ani Muscle

3D Finite Element Simulation for Turning of Hardened 45 Steel

2019 ◽  
Vol 13 (2) ◽  
pp. 181-188
Author(s):  
Meng Liu ◽  
Guohe Li ◽  
Xueli Zhao ◽  
Xiaole Qi ◽  
Shanshan Zhao
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cutting Force ◽  
Finite Element Simulation ◽  
Orthogonal Experiment ◽  
Element Model ◽  
3D Finite Element ◽  
Element Simulation ◽  
Metal Machining ◽  
Single Factor Experiment

Background: Finite element simulation has become an important method for the mechanism research of metal machining in recent years. Objective: To study the cutting mechanism of hardened 45 steel (45HRC), and improve the processing efficiency and quality. Methods: A 3D oblique finite element model of traditional turning of hardened 45 steel based on ABAQUS was established in this paper. The feasibility of the finite element model was verified by experiment, and the influence of cutting parameters on cutting force was predicted by single factor experiment and orthogonal experiment based on simulation. Finally, the empirical formula of cutting force was fitted by MATLAB. Besides, a lot of patents on 3D finite element simulation for metal machining were studied. Results: The results show that the 3D oblique finite element model can predict three direction cutting force, the 3D chip shape, and other variables of metal machining and the prediction errors of three direction cutting force are 5%, 9.02%, and 8.56%. The results of single factor experiment and orthogonal experiment are in good agreement with similar research, which shows that the model can meet the needs for engineering application. Besides, the empirical formula and the prediction results of cutting force are helpful for the parameters optimization and tool design. Conclusion: A 3D oblique finite element model of traditional turning of hardened 45 steel is established, based on ABAQUS, and the validation is carried out by comparing with experiment.

scholarly journals 3D finite element model of dynamic material behaviors for multilayer ultrasonic metal welding

2021 ◽  
Vol 62 ◽  
pp. 302-312
Author(s):  
Ninggang Shen ◽  
Avik Samanta ◽  
Wayne W. Cai ◽  
Teresa Rinker ◽  
Blair Carlson ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
3D Finite Element ◽  
Ultrasonic Metal Welding ◽  
3D Finite Element Model ◽  
Material Behaviors ◽  
Metal Welding

scholarly journals A Novel, Improved Equivalent Circuit Model for Double-Sided Linear Induction Motor

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1644
Author(s):  
Qian Zhang ◽  
Huijuan Liu ◽  
Tengfei Song ◽  
Zhenyang Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Equivalent Circuit ◽  
Skin Effect ◽  
Equivalent Circuit Model ◽  
Element Model ◽  
Circuit Model ◽  
End Effects ◽  
3D Finite Element ◽  
Linear Induction

A novel, improved equivalent circuit model of double-sided linear induction motors (DLIMs) is proposed, which takes the skin effect and the nonzero leakage reactance of the secondary, longitudinal, and transverse end effects into consideration. Firstly, the traditional equivalent circuit with longitudinal and transverse end effects are briefly reviewed. Additionally, the correction coefficients for longitudinal and transverse end effects derived by one-dimensional analysis models are given. Secondly, correction factors for skin effect, which reflects the inhomogeneous air gap magnetic field vertically, and the secondary leakage reactance are derived by the quasi-two-dimensional analysis model. Then, the proposed equivalent circuit is presented, and the excitation reactance and secondary resistance are modified by the correction coefficients derived from the three analytical models. Finally, a three-dimensional (3D) finite element model is used to verify the proposed equivalent circuit model under varying air gap width and frequency, and the results are also compared with that of the traditional equivalent circuit models. The calculated thrust characteristics by the proposed equivalent circuit and 3D finite element model are experimentally validated under a constant voltage–frequency drive.

scholarly journals Animal models for pelvic organ prolapse: systematic review

2021 ◽  
Author(s):  
Marina Gabriela M. C. Mori da Cunha ◽  
Katerina Mackova ◽  
Lucie Hajkova Hympanova ◽  
Maria Augusta T. Bortolini ◽  
Jan Deprest
Keyword(s):  
Pelvic Organ Prolapse ◽  
Animal Models ◽  
Vaginal Delivery ◽  
Structural Changes ◽  
Meta Analysis ◽  
Levator Ani ◽  
Complete Recovery ◽  
Pelvic Organ ◽  
Squirrel Monkeys ◽  
Levator Ani Muscle

Abstract Introduction and hypothesis We aimed to summarize the knowledge on the pathogenesis of pelvic organ prolapse (POP) generated in animal models. Methods We searched MEDLINE, Embase, Cochrane and the Web of Science to establish what animal models are used in the study of suggested risk factors for the development of POP, including pregnancy, labor, delivery, parity, aging and menopause. Lack of methodologic uniformity precluded meta-analysis; hence, results are presented as a narrative review. Results A total of 7426 studies were identified, of which 51 were included in the analysis. Pregnancy has a measurable and consistent effect across species. In rats, simulated vaginal delivery induces structural changes in the pelvic floor, without complete recovery of the vaginal muscular layer and its microvasculature, though it does not induce POP. In sheep, first vaginal delivery has a measurable effect on vaginal compliance; measured effects of additional deliveries are inconsistent. Squirrel monkeys can develop POP. Denervation of their levator ani muscle facilitates this process in animals that delivered vaginally. The models used do not develop spontaneous menopause, so it is induced by ovariectomy. Effects of menopause depend on the age at ovariectomy and the interval to measurement. In several species menopause is associated with an increase in collagen content in the longer term. In rodents there were no measurable effects of age apart of elastin changes. We found no usable data for other species. Conclusion In several species there are measurable effects of pregnancy, delivery and iatrogenic menopause. Squirrel monkeys can develop spontaneous prolapse.

scholarly journals Biomechanical characteristics of tibio-femoral joint after partial medial meniscectomy in different flexion angles: a finite element analysis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xiaohui Zhang ◽  
Shuo Yuan ◽  
Jun Wang ◽  
Bagen Liao ◽  
De Liang
Keyword(s):  
Finite Element ◽  
Articular Cartilage ◽  
Finite Element Model ◽  
Medial Meniscus ◽  
Lateral Meniscus ◽  
Element Model ◽  
Magnetic Resonance Images ◽  
Biomechanical Analysis ◽  
Joint Stress ◽  
Tibiofemoral Joint

Abstract Background Recent studies have pointed out that arthroscopy, the commonly-used surgical procedure for meniscal tears, may lead to an elevated risk of knee osteoarthritis (KOA). The biomechanical factors of KOA can be clarified by the biomechanical analysis after arthroscopic partial meniscectomy (APM). This study aimed to elucidate the cartilage stress and meniscus displacement of the tibiofemoral joint under flexion and rotation loads after APM. Methods A detailed finite element model of the knee bone, cartilage, meniscus, and major ligaments was established by combining computed tomography and magnetic resonance images. Vertical load and front load were applied to simulate different knee buckling angles. At the same time, by simulating flexion of different degrees and internal and external rotations, the stresses on tibiofemoral articular cartilage and meniscus displacement were evaluated. Results Generally, the contact stress on both the femoral tibial articular cartilage and the meniscus increased with the increased flexion degree. Moreover, the maximum stress on the tibial plateau gradually moved backward. The maximum position shift value of the lateral meniscus was larger than that of the medial meniscus. Conclusion Our finite element model provides a realistic three-dimensional model to evaluate the influence of different joint range of motion and rotating tibiofemoral joint stress distribution. The decreased displacement of the medial meniscus may explain the higher pressure on the knee components. These characteristics of the medial tibiofemoral joint indicate the potential biomechanical risk of knee degeneration.

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