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Dubik J, Tartaglione A, Miller KS, Dillard DA, De Vita R. History-Dependent Deformations of Rat Vaginas under Inflation. Integr Comp Biol 2022; 62:icac110. [PMID: 35781491 DOI: 10.1093/icb/icac110] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The vagina is a highly inhomogeneous, anisotropic, and viscoelastic organ that undergoes significant deformations in vivo. The mechanical attributes of this organ facilitate important physiological functions during menstruation, intercourse, and birthing. Despite the crucial mechanical role that the vagina plays within the female reproductive system, the deformations that the organ can sustain over time under constant pressure, in both the longitudinal direction (LD) and circumferential direction (CD), have not been fully characterized. This experimental study focuses on quantifying the creep properties of the vagina via ex vivo inflation testing using the rat as animal model. Toward this end, rat vaginas were subjected to three consecutively increasing constant luminal pressures (28 kPa, 55 kPa, and 83 kPa) using a custom-built experimental setup and the resulting inhomogeneous deformations were measured using the digital image correlation (DIC) method. The vagina was found to deform significantly more in the CD than the LD at any constant pressure, suggesting that the organ primarily adapts to constant pressures by significantly changing the diameter rather that the length. The change in deformation over time (i.e., creep) was significantly higher during the 1st inflation test at a constant pressure of 28 kPa than over the 2nd and 3rd inflation tests at constant pressures of 55 kPa and 83 kPa, respectively. The findings of this study on the mechanical behavior of the vagina could serve to advance our limited knowledge about the physiology and pathophysiology of this important reproductive organ.
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Affiliation(s)
- Justin Dubik
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, 330A Kelly Hall, 325 Stanger Street, Blacksburg, 24061, VA, USA
| | - Alfonsina Tartaglione
- Department of Mathematics and Physics, Università degli Studi della Campania "Luigi Vanvitelli", Viale Abramo Lincoln 5, Caserta, 81100, CE, Italy
| | - Kristin S Miller
- Department of Biomedical Engineering, Tulane University, 531 Lindy Boggs, New Orleans, 70118, LA, USA
| | - David A Dillard
- Department of Biomedical Engineering and Mechanics, Virginia Tech, 219A Norris Hall, 495 Old Turner Street, Blacksburg, 24061, VA, USA
| | - Raffaella De Vita
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, 330A Kelly Hall, 325 Stanger Street, Blacksburg, 24061, VA, USA
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Eltony AM, Shao P, Yun SH. Measuring mechanical anisotropy of the cornea with Brillouin microscopy. Nat Commun 2022; 13:1354. [PMID: 35293388 PMCID: PMC8924229 DOI: 10.1038/s41467-022-29038-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 02/17/2022] [Indexed: 12/13/2022] Open
Abstract
Load-bearing tissues are typically fortified by networks of protein fibers, often with preferential orientations. This fiber structure imparts the tissues with direction-dependent mechanical properties optimized to support specific external loads. To accurately model and predict tissues’ mechanical response, it is essential to characterize the anisotropy on a microstructural scale. Previously, it has been difficult to measure the mechanical properties of intact tissues noninvasively. Here, we use Brillouin optical microscopy to visualize and quantify the anisotropic mechanical properties of corneal tissues at different length scales. We derive the stiffness tensor for a lamellar network of collagen fibrils and use angle-resolved Brillouin measurements to determine the longitudinal stiffness coefficients (longitudinal moduli) describing the ex vivo porcine cornea as a transverse isotropic material. Lastly, we observe significant mechanical anisotropy of the human cornea in vivo, highlighting the potential for clinical applications of off-axis Brillouin microscopy. Here, Brillouin optical microscopy noninvasively visualizes microscale anisotropy of the porcine cornea owing to its lamellar fiber structure and quantifies the longitudinal moduli of the bulk tissue. Anisotropy is also detected in angle-resolved measurement of the human cornea in vivo.
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Affiliation(s)
- Amira M Eltony
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Peng Shao
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, 02114, USA.,Reveal Surgical Inc., Montréal, QC, H2N 1A4, Canada
| | - Seok-Hyun Yun
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, 02114, USA. .,Harvard-MIT Health Sciences and Technology, Cambridge, MA, 02139, USA.
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3
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Huntington AJ, Udayasuryan B, Du P, Verbridge SS, Abramowitch SD, Vita RD. Smooth Muscle Organization and Nerves in the Rat Vagina: A First Look Using Tissue Clearing and Immunolabeling. Ann Biomed Eng 2022; 50:440-451. [PMID: 35182248 DOI: 10.1007/s10439-022-02928-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 02/06/2022] [Indexed: 12/28/2022]
Abstract
Smooth muscle fibers within the vagina, as well as the nerve fibers that contribute to their control mechanisms, are important for the maintenance and alteration of vaginal length and tone. Vaginal smooth muscle (VaSM) is typically described as being arranged into two distinct concentric layers: an inner circular muscular layer and an outer longitudinal muscular layer. However, the distribution of VaSM oriented in the longitudinal direction (LD) and circumferential direction (CD) has never been quantified. In this study, tissue clearing and immunohistochemistry were performed so that the VaSM, and surrounding nerves, within whole rat vaginas ([Formula: see text]) could be imaged without tissue sectioning, preserving the three-dimensional architecture of the organs. Using these methods, the vagina was viewed through the full thickness of the muscularis layer, from the distal to the proximal regions. The VaSM orientation in the proximal and distal regions and the VaSM content along the LD and CD were quantified. Additionally, a qualitative assessment of vaginal nerves was performed. When compared using a permuted version of the Watson [Formula: see text] test, the orientation of VaSM in the proximal and distal regions were found to be significantly different in 4 of the 6 imaged rat vaginas ([Formula: see text]). While the distal vagina contained a similar amount of VaSM oriented within [Formula: see text] of the LD and within [Formula: see text] of the CD, the proximal vagina contained significantly more VaSM oriented towards the LD than towards the CD. Nerve fibers were found to be wavy, running both parallel and perpendicular to vascular and non-vascular smooth muscle within the vagina. Micro-structural analyses, like the one conducted here, are necessary to understand the physiological function and pathological changes of the vagina.
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Affiliation(s)
- Alyssa J Huntington
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, 330A Kelly Hall, 325 Stanger Street, Blacksburg, 24061, VA, USA
| | - Barath Udayasuryan
- Department of Biomedical Engineering and Mechanics, Virginia Tech, 330 Kelly Hall, 325 Stanger Street, Blacksburg, 24061, VA, USA
| | - Pang Du
- Department of Statistics, Virginia Tech, 417A Hutcheson Hall, 250 Drillfield Drive, Blacksburg, 24061, VA, USA
| | - Scott S Verbridge
- Department of Biomedical Engineering and Mechanics, Virginia Tech, 330 Kelly Hall, 325 Stanger Street, Blacksburg, 24061, VA, USA
| | - Steven D Abramowitch
- Translational Biomechanics Lab, Department of Bioengineering, University of Pittsburgh, Benedum Hall, 3700 O'Hara Street, Pittsburgh, 15213, PA, USA
| | - Raffaella De Vita
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, 330A Kelly Hall, 325 Stanger Street, Blacksburg, 24061, VA, USA.
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4
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Lauterbach R, Gruenwald I, Ersheed A, Mattar K, Matanes E, Justman N, Amnon A, Lowenstein L. Tension Free Vaginal Tape for Repair of Stress Urinary Incontinence Affects Vaginal Elasticity and Sexual Function. J Gynecol Surg 2022. [DOI: 10.1089/gyn.2021.0149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Roy Lauterbach
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, and Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Ilan Gruenwald
- Department of Neuro-Urology, Rambam Health Care Campus, and Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Angie Ersheed
- Department of Obstetrics and Gynecology, Ha`emek Medical Center, and Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Kamel Mattar
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, and Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Emad Matanes
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, and Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Naphtali Justman
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, and Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Amit Amnon
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, and Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Lior Lowenstein
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, and Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
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Kirilova-Doneva M, Pashkouleva D. The effects of age and sex on the elastic mechanical properties of human abdominal fascia. Clin Biomech (Bristol, Avon) 2022; 92:105591. [PMID: 35131681 DOI: 10.1016/j.clinbiomech.2022.105591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 12/19/2021] [Accepted: 01/28/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND The abdominal hernias become more prevalent with age, that can adversely affect life quality. The mechanical properties of abdominal wall layers are supposed to play a significant role in developing of an abdominal hernia.The objective of this study was to determine the mechanical properties of the human abdominal layer - fascia and the effects of age and sex on it for choosing the proper brand of hernia mesh. METHODS 78 samples harvested from 19 fresh cadavers were subjected to uniaxial tension tests and divided into four groups according to age. Group A corresponds to age up to 60 years, Group B to age 61-70 years, Group C to age 71-80 years and Group D to 81-90 years. Median stress-stretch ratio curves with respect to age, sex and direction of loading were obtained. Median values of the maximum tensile stress, stretch at maximum stress and elastic modulus calculated at 5% strain were determined. FINDINGS The abdominal fascia showed large variations between specimens depending on age and sex. The stiffness of the fascia increased with age. There is statistically significant differences between the median curves of male samples (P = 0.008) and female samples (P = 0.019) according to age in the L direction. Statistically significant differences between the values of maximum stress (P = 0.01) and elastic modulus (P = 0.003) from Group C in the L direction and maximum stress (P = 0.03) from Group D in the T direction was established. INTERPRETATION The female samples are stiffer than male samples especially after 80 years.
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Affiliation(s)
- Miglena Kirilova-Doneva
- Faculty of Pharmacy, Medical University-Sofia, Sofia, Bulgaria; Institute of Mechanics, Bulgarian Academy of Sciences, Sofia, Bulgaria.
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Lauterbach R, Gutzeit O, Matanes E, Linder R, Mick I, Aharoni S, Gruenwald I, Wiener Z, Lowenstein L. Vaginal Fractional Carbon Dioxide Laser Treatment and Changes in Vaginal Biomechanical Parameters. Lasers Surg Med 2021; 53:1146-1151. [PMID: 33834503 DOI: 10.1002/lsm.23405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND OBJECTIVES Vaginal fractional carbon dioxide (CO2 ) laser treatment has emerged in the past two decades as a non-surgical option for vaginal tightening. Mounting evidence supports the effectiveness and safety of this treatment for female sexual dysfunction. A newly developed vaginal tactile imaging (VTI) technique accurately evaluates the biomechanical parameters of the female pelvic floor and vagina, including tissue elasticity, pelvic support, and pelvic muscle function in high definition. In the current study, we evaluated changes in objective biomechanical parameters using VTI, following vaginal CO2 laser treatment for vaginal tightening and sexual dysfunction. STUDY DESIGN/MATERIALS AND METHODS We conducted a prospective cohort between June 2018 and January 2020. Inclusion criteria were vaginal looseness, decreased local sensation during sexual intercourse, and sexual dysfunction. All the participants were treated with a vaginal carbon dioxide laser. They underwent a gynecological evaluation based on the Vaginal Health Index (VHI) and sexual function assessment according to the Female Sexual Function Index (FSFI). Vaginal biomechanical parameters were assessed by VTI. Initial evaluations were performed at the pre-treatment consult visit, 1 week prior to the first treatment and at a 6-month post-treatment follow-up visit. RESULTS Twenty-five women were included in the final analysis. Compared with baseline, the post-treatment mean scores for vaginal elasticity and tightening were higher (54.8 ± 5.2 vs. 41.5 ± 6.3, P = 0.0027 and 1.97 ± 0.25 vs. 1.32 ± 0.31, P = 0.0014, respectively). Post-treatment increases were demonstrated in pelvic muscle contraction strength (25.9 ± 3.5 vs. 16.5 ± 4.2, P = 0.0011) and in reflex pelvic muscle contraction (2.93 ± 0.44 vs. 2.12 ± 0.47, P = 0.0022); the mean FSFI and VHI scores were higher following treatment (28.47 ± 1.73 vs. 21.12 ± 1.58, P = 0.036 and 19.15 ± 1.27 vs. 11.6 ± 0.97, P = 0.0032). CONCLUSIONS The quantification of vaginal biomechanical parameters using VTI technology offers objective evidence of the beneficial effect of vaginal CO2 laser treatment. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.
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Affiliation(s)
- Roy Lauterbach
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, 3525408, Israel
| | - Ola Gutzeit
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, 3525408, Israel
| | - Emad Matanes
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, 3525408, Israel
| | - Revital Linder
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, 3525408, Israel
| | - Ido Mick
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, 3525408, Israel
| | - Saar Aharoni
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, 3525408, Israel
| | - Ilan Gruenwald
- Neuro-urology Unit, Rambam Medical Center, Technion, Faculty of Medicine, Haifa, 3525408, Israel
| | - Zeev Wiener
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, 3525408, Israel
| | - Lior Lowenstein
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, 3525408, Israel
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7
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Pack E, Dubik J, Snyder W, Simon A, Clark S, De Vita R. Biaxial Stress Relaxation of Vaginal Tissue in Pubertal Gilts. J Biomech Eng 2020; 142:031002. [PMID: 31833537 DOI: 10.1115/1.4045707] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Indexed: 01/04/2023]
Abstract
Pelvic organ prolapse (POP) is a condition characterized by displacement of the vagina from its normal anatomical position leading to symptoms such as incontinence, physical discomfort, and poor self-image. Conservative treatment has shown limited success and surgical procedures, including the use of mesh, often lead to severe complications. To improve the current treatment methods for prolapse, the viscoelastic properties of vaginal tissue need to be characterized. We determined the biaxial stress relaxation response of vaginal tissue isolated from healthy pubertal gilts. Square specimens (n = 20) with sides aligned along the longitudinal directions (LD) and circumferential direction (CD) of the vagina were biaxially displaced up to 5 N. The specimens were then kept at the displacements corresponding to 5 N for 20 min in both the LD and CD, and the corresponding strains were measured using digital image correlation (DIC). The stresses in the LD and CD were found to decrease by 49.91 ± 5.81% and 46.22 ± 5.54% after 20 min, respectively. The strain in the LD and CD increased slightly from 0.080 ± 0.054 to 0.091 ± 0.064 and 0.050 ± 0.039 to 0.058 ± 0.047, respectively, but these changes were not significant (p > 0.01). By using the Peleg model, the initial decay rate and the asymptotic stress during stress relaxation were found to be significantly higher in the LD than in the CD (p≪0.001), suggesting higher stress relaxation in the LD. These findings may have implications for improving current surgical mesh, mechanical devices, and physical therapy used for prolapse treatment.
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Affiliation(s)
- Erica Pack
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061; STRETCH Lab, Department of Biomedical Engineering and Mechanics, and School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061
| | - Justin Dubik
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061
| | - William Snyder
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061
| | - Alexander Simon
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061
| | - Sherrie Clark
- Department of Large Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061
| | - Raffaella De Vita
- STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061
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8
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Tissue Anisotropy Modeling Using Soft Composite Materials. Appl Bionics Biomech 2018; 2018:4838157. [PMID: 29853996 PMCID: PMC5966707 DOI: 10.1155/2018/4838157] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 04/11/2018] [Indexed: 11/22/2022] Open
Abstract
Soft tissues in general exhibit anisotropic mechanical behavior, which varies in three dimensions based on the location of the tissue in the body. In the past, there have been few attempts to numerically model tissue anisotropy using composite-based formulations (involving fibers embedded within a matrix material). However, so far, tissue anisotropy has not been modeled experimentally. In the current work, novel elastomer-based soft composite materials were developed in the form of experimental test coupons, to model the macroscopic anisotropy in tissue mechanical properties. A soft elastomer matrix was fabricated, and fibers made of a stiffer elastomer material were embedded within the matrix material to generate the test coupons. The coupons were tested on a mechanical testing machine, and the resulting stress-versus-stretch responses were studied. The fiber volume fraction (FVF), fiber spacing, and orientations were varied to estimate the changes in the mechanical responses. The mechanical behavior of the soft composites was characterized using hyperelastic material models such as Mooney-Rivlin's, Humphrey's, and Veronda-Westmann's model and also compared with the anisotropic mechanical behavior of the human skin, pelvic tissues, and brain tissues. This work lays the foundation for the experimental modelling of tissue anisotropy, which combined with microscopic studies on tissues can lead to refinements in the simulation of localized fiber distribution and orientations, and enable the development of biofidelic anisotropic tissue phantom materials for various tissue engineering and testing applications.
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9
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Robison KM, Conway CK, Desrosiers L, Knoepp LR, Miller KS. Biaxial Mechanical Assessment of the Murine Vaginal Wall Using Extension-Inflation Testing. J Biomech Eng 2018; 139:2648715. [PMID: 28787477 DOI: 10.1115/1.4037559] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Indexed: 12/31/2022]
Abstract
Progress toward understanding the underlying mechanisms of pelvic organ prolapse (POP) is limited, in part, due to a lack of information on the biomechanical properties and microstructural composition of the vaginal wall. Compromised vaginal wall integrity is thought to contribute to pelvic floor disorders; however, normal structure-function relationships within the vaginal wall are not fully understood. In addition to the information produced from uniaxial testing, biaxial extension-inflation tests performed over a range of physiological values could provide additional insights into vaginal wall mechanical behavior (i.e., axial coupling and anisotropy), while preserving in vivo tissue geometry. Thus, we present experimental methods of assessing murine vaginal wall biaxial mechanical properties using extension-inflation protocols. Geometrically intact vaginal samples taken from 16 female C57BL/6 mice underwent pressure-diameter and force-length preconditioning and testing within a pressure-myograph device. A bilinear curve fit was applied to the local stress-stretch data to quantify the transition stress and stretch as well as the toe- and linear-region moduli. The murine vaginal wall demonstrated a nonlinear response resembling that of other soft tissues, and evaluation of bilinear curve fits suggests that the vagina exhibits pseudoelasticity, axial coupling, and anisotropy. The protocols developed herein permit quantification of biaxial tissue properties. These methods can be utilized in future studies in order to assess evolving structure-function relationships with respect to aging, the onset of prolapse, and response to potential clinical interventions.
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Affiliation(s)
- Kathryn M Robison
- Mem. ASME Department of Biomedical Engineering, Tulane University, 6823 St. Charles Avenue, New Orleans, LA 70118 e-mail:
| | - Cassandra K Conway
- Department of Biomedical Engineering, Tulane University, 6823 St. Charles Avenue, New Orleans, LA 70118 e-mail:
| | - Laurephile Desrosiers
- Department of Female Pelvic Medicine & Reconstructive Surgery, Ochsner Clinical School, 1514 Jefferson Highway, New Orleans, LA 70121 e-mail:
| | - Leise R Knoepp
- Department of Female Pelvic Medicine & Reconstructive Surgery, Ochsner Clinical School, 1514 Jefferson Highway, New Orleans, LA 70121 e-mail:
| | - Kristin S Miller
- Mem. ASME Department of Biomedical Engineering, Tulane University, 6823 St. Charles Avenue, New Orleans, LA 70118 e-mail:
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Chrysanthopoulou EL, Pergialiotis V, Perrea D, Κourkoulis S, Verikokos C, Doumouchtsis SK. Platelet rich plasma as a minimally invasive approach to uterine prolapse. Med Hypotheses 2017; 104:97-100. [PMID: 28673602 DOI: 10.1016/j.mehy.2017.05.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 05/24/2017] [Indexed: 12/19/2022]
Abstract
Pelvic organ prolapse (POP) is a major health problem that affects many women with potentially severe physical and psychological impact as well as impact on their daily activities, and quality of life. Several surgical techniques have been proposed for the treatment of POP. The FDA has published documents that refer to concerns about the use of synthetic meshes for the treatment of prolapse, in view of the severe complications that may occur. These led to hesitancy in use of these meshes and partial increase in use of other biological grafts such as allografts and xenografts. Although there seems to be an increasing tendency to use grafts in pelvic floor reconstructive procedures due to lower risks of erosion than synthetic meshes, there are inconclusive data to support the routine use of biological grafts in pelvic organ prolapse treatment. In light of these observations new strategies are needed for the treatment of prolapse. Platelet rich plasma (PRP) is extremely rich in growth factors and cytokines, which regulate tissue reconstruction and has been previously used in orthopaedics and plastic surgery. To date, however, it has never been used in urogynaecology and there is no evidence to support or oppose its use in women who suffer from POP, due to uterine ligament defects. PRP is a relatively inexpensive biological material and easily produced directly from patients' blood and is, thus, superior to synthetic materials in terms of potential adverse effects such as foreign body reaction. In the present article we summarize the existing evidence, which supports the conduct of animal experimental and clinical studies to elucidate the potential role of PRP in treating POP by restoring the anatomy and function of ligament support.
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Affiliation(s)
- E L Chrysanthopoulou
- Laboratory of Experimental Surgery and Surgical Research N.S. Christeas, National and Kapodistrian University of Athens, Greece; Department of Obstetrics and Gynaecology, Queen's Hospital, Rom Valley Way, Romford, Essex, United Kingdom.
| | - V Pergialiotis
- Laboratory of Experimental Surgery and Surgical Research N.S. Christeas, National and Kapodistrian University of Athens, Greece
| | - D Perrea
- Laboratory of Experimental Surgery and Surgical Research N.S. Christeas, National and Kapodistrian University of Athens, Greece
| | | | - C Verikokos
- Laboratory of Experimental Surgery and Surgical Research N.S. Christeas, National and Kapodistrian University of Athens, Greece; 2nd Department of Surgery, Vascular Surgery Unit, Laiko General Hospital, Medical School of Athens, Greece
| | - S K Doumouchtsis
- Laboratory of Experimental Surgery and Surgical Research N.S. Christeas, National and Kapodistrian University of Athens, Greece; Department of Obstetrics and Gynaecology, Epsom and St Helier University Hospitals NHS Trust, United Kingdom; St George's University of London, London, United Kingdom
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11
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Ribeiro J, Lopes H, Martins P. A hybrid method to characterise the mechanical behaviour of biological hyper-elastic tissues. COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING: IMAGING & VISUALIZATION 2016. [DOI: 10.1080/21681163.2015.1034295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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12
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Berardi M, Martinez-Romero O, Elías-Zúñiga A, Rodríguez M, Ceretti E, Fiorentino A, Donzella G, Avanzini A. Levator ani deformation during the second stage of labour. Proc Inst Mech Eng H 2014; 228:501-508. [PMID: 24793220 DOI: 10.1177/0954411914533678] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A very important medical problem for females is urinary incontinence, sometimes associated with faecal incontinence and pelvic organ prolapse. One of the most common reasons these issues are increasing is clearly the muscle damage during childbirth. This article focusses on understanding the complex behaviour of the levator ani muscles involved in the second stage of labour. A geometrical model obtained from a 23-year-old nulliparous woman was used to simulate childbirth. Several assumptions were introduced in order to simplify the problem without significantly affecting the global response of the system. An anisotropic hyperelastic model was used to characterize the material behaviour; the muscle fibres were assumed to be mostly orientated circumferentially. In addition, particular attention was also put to the boundary conditions of the model. The introduction of the constraints imposed by the coccyx bone in the central area of the levator ani group represents one the most important improvement compared to previous computational models. The maximum deformation and stress were found in the pubococcygeus muscle of the levator ani group. A stretch value close to 2.2 was determined by considering different material parameters. The results seem convincing with respect to medical observation and previous analysis. However, there are still some limitations concerning the material definition and the geometry and trajectory of the head that can be further improved.
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Affiliation(s)
- Mario Berardi
- Department of Mechanical and Industrial Engineering, University of Brescia, Brescia, Italy
| | | | - Alex Elías-Zúñiga
- Departamento de Ingeniería Mecánica, Tecnológico de Monterrey, Monterrey, México
| | - Mauricio Rodríguez
- Departamento de Ingeniería Mecánica, Tecnológico de Monterrey, Monterrey, México
| | - Elisabetta Ceretti
- Department of Mechanical and Industrial Engineering, University of Brescia, Brescia, Italy
| | - Antonio Fiorentino
- Department of Mechanical and Industrial Engineering, University of Brescia, Brescia, Italy
| | - Giorgio Donzella
- Department of Mechanical and Industrial Engineering, University of Brescia, Brescia, Italy
| | - Andrea Avanzini
- Department of Mechanical and Industrial Engineering, University of Brescia, Brescia, Italy
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13
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The influence of regional profiles and senescence on the biomechanical properties of the temporalis muscle. J Biomech 2013; 46:1592-5. [DOI: 10.1016/j.jbiomech.2013.03.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 02/19/2013] [Accepted: 03/18/2013] [Indexed: 11/22/2022]
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Martins P, Lopes Silva-Filho A, Rodrigues Maciel da Fonseca AM, Santos A, Santos L, Mascarenhas T, Natal Jorge RM, Ferreira AJM. Biomechanical properties of vaginal tissue in women with pelvic organ prolapse. Gynecol Obstet Invest 2012; 75:85-92. [PMID: 23295833 DOI: 10.1159/000343230] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 08/23/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS To compare biomechanical properties of vaginal tissues between women with and without pelvic organ prolapse (POP) and investigate factors that may influence these properties. METHODS Forty patients submitted to POP surgery and 15 non-POP cadavers were evaluated. The tissue was excised from anterior and posterior middle third vagina. The biomechanical properties considered were stiffness (E) and maximum stress (S), and they were evaluated by means of uniaxial tension tests. RESULTS POP patients were associated with higher values of E (13.1 ± 0.8 vs. 9.5 ± 0.7 MPa; p < 0.001) and S (5.3 ± 0.5 vs. 3.2 ± 0.9 MPa; p < 0.001) in the anterior vaginal wall compared to the posterior wall. In contrast, non-POP women presented lower values of E (6.9 ± 1.1 vs. 10.5 ± 1.0 MPa; p = 0.01) and S (2.6 ± 0.4 vs. 3.5 ± 0.4 MPa; p = 0.043) in the anterior wall. The occurrence of POP was the only independent predictor of higher values of E and S in anterior vaginal samples (p = 0.003 and p = 0.008, respectively). Women with severe anterior vaginal prolapse presented higher levels of E and S in the anterior sample compared to those with lower POP stages (p = 0.001 and p = 0.01; respectively). CONCLUSION Women with POP present significant changes of biomechanical properties in the vagina.
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Affiliation(s)
- Pedro Martins
- Department of Gynecology and Obstetrics, Faculty of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil
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Martins P, Silva-Filho AL, Fonseca AMRM, Santos A, Santos L, Mascarenhas T, Jorge RMN, Ferreira AM. Strength of round and uterosacral ligaments: a biomechanical study. Arch Gynecol Obstet 2012; 287:313-8. [PMID: 23001414 DOI: 10.1007/s00404-012-2564-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Accepted: 09/10/2012] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate the tensile biomechanical properties of round and uterosacral ligaments. METHODS Tissue samples were obtained from 15 female cadavers without pelvic organ prolapse. Uniaxial tensile tests were performed to obtain stiffness and maximum stress of round and uterosacral ligaments. Correlations were calculated using the Pearson correlation coefficient. Statistical differences between groups were tested using Student's paired and unpaired t test. RESULTS There was a great variability in the measurements of stiffness and maximum stress in pelvic ligaments. The round ligaments demonstrated stiffness of 9.1 ± 1.6 MPa (mean ± SEM) (ranging from 2 to 25.6 MPa) and maximum stress of 4.3 ± 0.7 MPa (ranging from 1.2 to 11.5 MPa). The stiffness of the uterosacral ligaments was 14.1 ± 1.4 MPa (ranging from 5.7 to 26.1 MPa) with maximum stress of 6.3 ± 0.8 MPa (ranging from 2.2 to 11.9 MPa). There was a strong positive correlation between stiffness and maximum stress in female pelvic ligaments (ρ = 0.851; p < 0.001). The uterosacral ligaments demonstrated higher stiffness and maximum stress compared to the round ligaments (p = 0.006 and p = 0.034; respectively). Age, body mass index and menopausal status were not associated with the biomechanical proprieties of round and uterosacral ligaments. Nulliparous women had lower uterosacral stiffness (15.5 ± 1.3 vs. 10 ± 1.8 MPa; p = 0.033) and maximum stress (8.2 ± 0.9 vs. 4.2 ± 1.1 MPa; p = 0.028) compared to parous women. CONCLUSION The uterosacral ligaments are significantly more resistant than round ligaments. Parturition seems to enhance the stiffness and maximum stress of the ligaments.
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Affiliation(s)
- Pedro Martins
- IDMEC-Polo FEUP, Faculty of Engineering, University of Porto, Porto, Portugal
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Comparative analysis of pelvic ligaments: a biomechanics study. Int Urogynecol J 2012; 24:135-9. [PMID: 22751993 DOI: 10.1007/s00192-012-1861-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 06/10/2012] [Indexed: 12/28/2022]
Abstract
INTRODUCTION AND HYPOTHESIS Pelvic organ prolapse (POP) affects one third of women of all ages and is a major concern for gynecological surgeons. In pelvic reconstructive surgery, native ligaments are widely used as a corrective support, while their biomechanical properties are unknown. We hypothesized differences in the strength of various pelvic ligaments and therefore, aimed to evaluate and compare their biomechanical properties. MATERIALS AND METHODS Samples from the left and right broad, round, and uterosacral ligaments from 13 fresh female cadavers without pelvic organ prolapse were collected. Uniaxial tension tests at a constant rate of deformation were performed and stress-strain curves were obtained. RESULTS We observed a non-linear stress-strain relationship and a hyperelastic mechanical behavior of the tissues. The uterosacral ligaments were the most rigid whether at low or high deformation, while the round ligament was more rigid than the broad ligament. CONCLUSION Pelvic ligaments differ in their biomechanical properties and there is fairly good evidence that the uterosacral ligaments play an important role in the maintenance of pelvic support from a biomechanical point of view.
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Egorov V, van Raalte H, Lucente V. Quantifying vaginal tissue elasticity under normal and prolapse conditions by tactile imaging. Int Urogynecol J 2012; 23:459-66. [PMID: 22072417 PMCID: PMC3306492 DOI: 10.1007/s00192-011-1592-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 10/17/2011] [Indexed: 02/04/2023]
Abstract
INTRODUCTION AND HYPOTHESIS Vaginal tactile imaging (VTI) is based on principles similar to those of manual palpation. The objective of this study is to assess the clinical suitability of new approach for imaging and tissue elasticity quantification under normal and prolapse conditions. METHODS The study subjects included 31 women with normal and prolapse conditions. The tissue elasticity (Young's modulus) was calculated from spatial gradients in the resulting 3-D tactile images. RESULTS Average values for tissue elasticity for the anterior and posterior compartments for normal conditions were 7.4 ± 4.3 kPa and 6.2 ± 3.1 kPa respectively. For Stage III prolapse the average values for tissue elasticity for anterior and posterior compartments were 1.8 ± 0.7 kPa and 1.8 ± 0.5 kPa respectively. CONCLUSIONS VTI may serve as a means for 3-D imaging of the vagina and a quantitative assessment of vaginal tissue elasticity, providing important information for furthering our understanding of pelvic organ prolapse and surgical treatment.
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Mechanical characterization and constitutive modelling of the damage process in rectus sheath. J Mech Behav Biomed Mater 2012; 8:111-22. [DOI: 10.1016/j.jmbbm.2011.12.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 11/26/2011] [Accepted: 12/16/2011] [Indexed: 11/23/2022]
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Trindade V, Martins P, Santos S, Parente M, Natal Jorge R, Santos A, Santos L, Fernandes J. Experimental study of the influence of senescence in the biomechanical properties of the temporal tendon and deep temporal fascia based on uniaxial tension tests. J Biomech 2012; 45:199-201. [DOI: 10.1016/j.jbiomech.2011.09.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 09/09/2011] [Accepted: 09/13/2011] [Indexed: 10/16/2022]
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Gabriel B, Rubod C, Brieu M, Dedet B, de Landsheere L, Delmas V, Cosson M. Vagina, abdominal skin, and aponeurosis: do they have similar biomechanical properties? Int Urogynecol J 2010; 22:23-7. [PMID: 20798926 DOI: 10.1007/s00192-010-1237-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 07/30/2010] [Indexed: 11/26/2022]
Abstract
INTRODUCTION AND HYPOTHESIS despite minimal fundamental works, there is an increasing use of meshes in urogynecology. The concept is mainly based on experiences with abdominal wall surgery. We aimed to compare the biomechanical properties of vaginal tissue, abdominal aponeurosis, and skin. METHODS samples from 11 fresh women cadavers without prolapse were collected. Uniaxial tension tests were performed and stress-strain curves were obtained. RESULTS biomechanical properties of the vagina, aponeurosis, and skin differed significantly. The aponeurosis was much more rigid and less extendible than the vagina and skin. Vaginal tissue was less rigid but more extendible than skin. There was no difference between the vagina and skin at low strains (p = 0.341), but a highly significant difference at large strains (p = 0.005). CONCLUSIONS skin and aponeurosis are not suited to predict vaginal tissue biomechanics. We should be cautious when transferring experiences from abdominal wall surgery to vaginal reconstructive surgery.
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Affiliation(s)
- Boris Gabriel
- Clinique de chirurgie gynécologique, Hopital Jeanne de Flandre, Centre Hospitalier Regional Universitaire de Lille, 2, av. Oscar Lambret, 59037 Lille Cedex, France.
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