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1.
Am J Obstet Gynecol ; 2024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38642697

RESUMO

BACKGROUND: The gold-standard treatment for advanced pelvic organ prolapse is sacrocolpopexy. However, the preoperative features of prolapse that predict optimal outcomes are unknown. OBJECTIVE: This study aimed to develop a clinical prediction model that uses preoperative scores on the Pelvic Organ Prolapse Quantification examination to predict outcomes after minimally invasive sacrocolpopexy for stages 2, 3, and 4 uterovaginal prolapse and vaginal vault prolapse. STUDY DESIGN: A 2-institution database of pre- and postoperative variables from 881 cases of minimally invasive sacrocolpopexy was analyzed. Data from patients were analyzed in the following 4 groups: stage 2 uterovaginal prolapse, stage 3 to 4 uterovaginal prolapse, stage 2 vaginal vault prolapse, and stage 3 to 4 vaginal vault prolapse. Unsupervised machine learning was used to identify clusters and investigate associations between clusters and outcome. The k-means clustering analysis was performed with preoperative Pelvic Organ Prolapse Quantification points and stratified by previous hysterectomy status. The "optimal" surgical outcome was defined as postoperative Pelvic Organ Prolapse Quantification stage <2. Demographic variables were compared by cluster with Student t and chi-square tests. Odds ratios were calculated to determine whether clusters could predict the outcome. Age at surgery, body mass index, and previous prolapse surgery were used for adjusted odds ratios. RESULTS: Five statistically distinct prolapse clusters (phenotypes C, A, A>P, P, and P>A) were found. These phenotypes reflected the predominant region of prolapse (apical, anterior, or posterior) and whether support was preserved in the nonpredominant region. Phenotype A (anterior compartment prolapse predominant, posterior support preserved) was found in all 4 groups of patients and was considered the reference in the analysis. In 111 patients with stage 2 uterovaginal prolapse, phenotypes A and A>P (greater anterior prolapse than posterior prolapse) were found, and patients with phenotype A were more likely than those with phenotype A>P to have an optimal surgical outcome. In 401 patients with stage 3 to 4 uterovaginal prolapse, phenotypes C (apical compartment predominant, prolapse in all compartments), A, and A>P were found, and patients with phenotype A>P were more likely than those with phenotype A to have ideal surgical outcome. In 72 patients with stage 2 vaginal vault prolapse, phenotypes A, A>P, and P (posterior compartment predominant, anterior support preserved) were found, and those with phenotype A>P were less likely to have an ideal outcome than patients with phenotype A. In 297 patients with stage 3 to 4 vaginal vault prolapse, phenotypes C, A, and P>A (prolapse greater in posterior than in anterior compartment) were found, but there were no significant differences in rate of ideal outcome between phenotypes. CONCLUSION: Five anatomic phenotypes based on preoperative Pelvic Organ Prolapse Quantification scores were present in patients with stages 2 and 3 to 4 uterovaginal prolapse and vaginal vault prolapse. These phenotypes are predictive of surgical outcome after minimally invasive sacrocolpopexy. Further work needs to confirm the presence and predictive nature of these phenotypes. In addition, whether the phenotypes represent a progression of prolapse or discrete prolapse presentations resulting from different anatomic and life course risk profiles is unknown. These phenotypes may be useful in surgical counseling and planning.

2.
Sci Rep ; 14(1): 586, 2024 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-38182631

RESUMO

Mammalian pregnancy requires gradual yet extreme remodeling of the reproductive organs to support the growth of the embryos and their birth. After delivery, the reproductive organs return to their non-pregnant state. As pregnancy has traditionally been understudied, there are many unknowns pertaining to the mechanisms behind this remarkable remodeling and repair process which, when not successful, can lead to pregnancy-related complications such as maternal trauma, pre-term birth, and pelvic floor disorders. This study presents the first longitudinal imaging data that focuses on revealing anatomical alterations of the vagina, cervix, and uterine horns during pregnancy and postpartum using the mouse model. By utilizing advanced magnetic resonance imaging (MRI) technology, T1-weighted and T2-weighted images of the reproductive organs of three mice in their in vivo environment were collected at five time points: non-pregnant, mid-pregnant (gestation day: 9-10), late pregnant (gestation day: 16-17), postpartum (24-72 h after delivery) and three weeks postpartum. Measurements of the vagina, cervix, and uterine horns were taken by analyzing MRI segmentations of these organs. The cross-sectional diameter, length, and volume of the vagina increased in late pregnancy and then returned to non-pregnant values three weeks after delivery. The cross-sectional diameter of the cervix decreased at mid-pregnancy before increasing in late pregnancy. The volume of the cervix peaked at late pregnancy before shortening by 24-72 h postpartum. As expected, the uterus increased in cross-sectional diameter, length, and volume during pregnancy. The uterine horns decreased in size postpartum, ultimately returning to their average non-pregnant size three weeks postpartum. The newly developed methods for acquiring longitudinal in vivo MRI scans of the murine reproductive system can be extended to future studies that evaluate functional and morphological alterations of this system due to pathologies, interventions, and treatments.


Assuntos
Imageamento por Ressonância Magnética , Útero , Feminino , Humanos , Gravidez , Animais , Camundongos , Útero/diagnóstico por imagem , Projetos de Pesquisa , Vagina/diagnóstico por imagem , Período Pós-Parto , Mamíferos
3.
Int Urogynecol J ; 35(3): 537-544, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38197952

RESUMO

INTRODUCTION AND HYPOTHESIS: Magnetic resonance defecography imaging techniques have been used widely to study pelvic floor function and diagnose pelvic organ prolapse (POP). The aim of this study was to investigate the diagnostic accuracy of the H-line to detect bladder descent compared with the current landmark, the pubococcygeal line (PCL). METHODS: In this retrospective cohort study, patients who underwent MR defecography in our medical center and were diagnosed with moderate to severe cystocele by radiological measurements were recruited. One rest image and one maximum evacuation image for each subject were used for the following measurements: bladder base perpendicular distance from the genital hiatus (GH), indicative of clinically significant bladder descent, PCL as the current radiological reference line, and the H-line, or minimal levator hiatus line, indicative of pelvic floor muscle and connective tissue support. Subjects were categorized as having clinically significant cystocele if the "bladder base" reached within 1 cm or lower of the GH (stage II or higher cystocele). A comparison was performed to assess differences and predictive capabilities of the reference lines relative to the GH measure. RESULTS: Seventy subjects were included, 30 with clinically significant bladder descent based on distance to GH. Women with bladder descent were older (64.0 ± 11.8 vs 51.2 ± 15.6, p < 0.001), had increased parity (3 [1-7] vs 2 [0-5], p = 0.009), and had a bladder that descended lower than the H-line at rest (1.9 ± 0.5 vs 2.2 ± 0.4, p = 0.003) and evacuation (-2.4 ± 1.6 vs -0.7 ± 1.1, p < 0.001). Multivariate regression analysis confirmed that age, length of the H-line at evacuation, the perpendicular distances between the H-line and the lowest bladder point at rest, and the PCL to the lowest bladder point at evacuation significantly correlated with bladder descent. Receiver operating characteristic analysis was used to identify a measurement threshold to diagnose clinically significant cystocele for both measurements, bladder base to the H-line: -1.2 (80.0, 72.5) area under the curve (AUC) 0.82, and bladder base PCL: -3.3 (77.8, 79.5) AUC 0.86. CONCLUSION: Our data support the application of using the minimal levator hiatus plane and specifically the H-line as a reliable landmark to diagnose bladder descent using MR defecography imaging.


Assuntos
Cistocele , Bexiga Urinária , Humanos , Feminino , Bexiga Urinária/diagnóstico por imagem , Defecografia/métodos , Estudos Retrospectivos , Diafragma da Pelve , Cistocele/diagnóstico por imagem , Cistocele/patologia , Imageamento por Ressonância Magnética/métodos
4.
BJOG ; 131(3): 267-277, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37522240

RESUMO

OBJECTIVE: To identify vaginal morphology and position factors associated with prolapse recurrence following vaginal surgery. DESIGN: Secondary analysis of magnetic resonance images (MRI) of the Defining Mechanisms of Anterior Vaginal Wall Descent cross-sectional study. SETTING: Eight clinical sites in the US Pelvic Floor Disorders Network. POPULATION OR SAMPLE: Women who underwent vaginal mesh hysteropexy (hysteropexy) with sacrospinous fixation or vaginal hysterectomy with uterosacral ligament suspension (hysterectomy) for uterovaginal prolapse between April 2013 and February 2015. METHODS: The MRI (rest, strain) obtained 30-42 months after surgery, or earlier for participants with recurrence who desired reoperation before 30 months, were analysed. MRI-based prolapse recurrence was defined as prolapse beyond the hymen at strain on MRI. Vaginal segmentations (at rest) were used to create three-dimensional models placed in a morphometry algorithm to quantify and compare vaginal morphology (angulation, dimensions) and position. MAIN OUTCOME MEASURES: Vaginal angulation (upper, lower and upper-lower vaginal angles in the sagittal and coronal plane), dimensions (length, maximum transverse width, surface area, volume) and position (apex, mid-vagina) at rest. RESULTS: Of the 82 women analysed, 12/41 (29%) in the hysteropexy group and 22/41 (54%) in the hysterectomy group had prolapse recurrence. After hysteropexy, women with recurrence had a more laterally deviated upper vagina (p = 0.02) at rest than women with successful surgery. After hysterectomy, women with recurrence had a more inferiorly (lower) positioned vaginal apex (p = 0.01) and mid-vagina (p = 0.01) at rest than women with successful surgery. CONCLUSIONS: Vaginal angulation and position were associated with prolapse recurrence and suggestive of vaginal support mechanisms related to surgical technique and potential unaddressed anatomical defects. Future prospective studies in women before and after prolapse surgery may distinguish these two factors.


Assuntos
Prolapso de Órgão Pélvico , Prolapso Uterino , Feminino , Humanos , Estudos Prospectivos , Estudos Transversais , Resultado do Tratamento , Procedimentos Cirúrgicos em Ginecologia/métodos , Vagina/diagnóstico por imagem , Vagina/cirurgia , Histerectomia Vaginal , Prolapso Uterino/cirurgia , Prolapso de Órgão Pélvico/cirurgia
5.
Comput Methods Programs Biomed ; 244: 107938, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38056313

RESUMO

BACKGROUND AND OBJECTIVES: Finite element simulations are widely employed as a non-invasive and cost-effective approach for predicting outcomes in biomechanical simulations. However, traditional finite element software, primarily designed for engineering materials, often encountered limitations in contact detection and enforcement, leading to simulation failure when dealing with complex biomechanical configurations. Currently, a lot of model tuning is required to get physically accurate finite element simulations without failures. This adds significant human interaction to each iteration of a biomechanical model. This study addressed these issues by introducing PolyFEM, a novel finite element solver that guarantees inversion- and intersection-free solutions with completely automatic collision detection. The objective of this research is to validate PolyFEM's capabilities by comparing its results with those obtained from a well-established finite element solver, FEBio. METHODS: To achieve this goal, five comparison scenarios were formulated to assess and validate PolyFEM's performance. The simulations were reproduced using both PolyFEM and FEBio, and the final results were compared. The five comparison scenarios included: (1) reproducing simulations from the FEBio test suite, consisting of static, dynamic, and contact-driven simulations; (2) replicating simulations from the verification paper published alongside the original release of FEBio; (3) a biomechanically based contact problem; (4) creating a custom simulation involving high-energy collisions between soft materials to highlight the difference in collision methods between the two solvers; and (5) performing biomechanical simulations of biting and quasi-stance. RESULTS: We found that PolyFEM was capable of replicating all simulations previously conducted in FEBio. Particularly noteworthy is PolyFEM's superiority in high-energy contact simulations, where FEBio fell short, unable to complete over half of the simulations in Scenario 4. Although some of the simulations required significantly more simulation time in PolyFEM compared to FEBio, it is important to highlight that PolyFEM achieved these results without the need for any additional model tuning or contact declaration. DISCUSSION: Despite being in the early stages of development, PolyFEM currently provides verified solutions for hyperelastic materials that are consistent with FEBio, both in previously published workflows and novel finite element scenarios. PolyFEM exhibited the ability to tackle challenging biomechanical problems where other solvers fell short, thus offering the potential to enhance the accuracy and realism of future finite element analyses.


Assuntos
Software , Humanos , Simulação por Computador , Fenômenos Biomecânicos , Análise de Elementos Finitos
6.
Ann Biomed Eng ; 52(2): 292-301, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37828266

RESUMO

Remodeling of the sacrum and coccyx to accommodate pregnancy and delivery has been hypothesized but not directly quantified. This study aimed to quantify the remodeling of the sacrum and coccyx by comparing midsagittal lengths, angles, curvature, and shape between nulliparous, pregnant, and parous women using both 2 and 3 dimensional measures. Ninety pelvic magnetic resonance images of the pelvis were retrospectively collected and segmented. Twelve length, angle, and curvature measurements were made using definitions from previous literature on the midsagittal plane to define the sacrum, coccyx, and combined sacrum-coccyx shape. These measures were followed by a statistical shape analysis, which returned modes of variation and principal component scores. A separate MANCOVA analysis was conducted for both the 2D and 3D measures. The 2D and 3D analyses agreed that pregnant women had a significantly straighter coccyx and combined sacrum/coccyx than nulliparous (9.1% and 5.6%, respectively) and parous (7.5% and 2.7%, respectively) subjects. All comparisons showed that, on average, a pregnant woman's sacrum and coccyx were significantly straighter than their nulliparous counterparts. Then after delivery, the sacrum/coccyx returned, but not completely back to a more curved configuration.


Assuntos
Cóccix , Sacro , Humanos , Feminino , Gravidez , Estudos Retrospectivos , Pelve , Imageamento por Ressonância Magnética
7.
Int Urogynecol J ; 34(10): 2399-2406, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37145123

RESUMO

INTRODUCTION AND HYPOTHESIS: Endovaginal ultrasound has long been hypothesized to have a significant effect on locations of what it visualizes. However, little work has directly quantified its effect. This study aimed to quantify it. METHODS: This cross-sectional study consisted of 20 healthy asymptomatic volunteers who underwent both endovaginal ultrasound and MRI. The urethra, vagina, rectum, pelvic floor, and pubic bone were segmented in both ultrasound and MRI using 3DSlicer. Then, using 3DSlicer's transform tool the volumes were rigidly aligned based on the posterior curvature of the pubic bone. The organs were then split into thirds along their long axis to compare their distal, middle, and proximal sections. Using Houdini, we compared the location of the centroid of each of the urethra, vagina, and rectum and the surface-to-surface difference of the urethra and rectum. The anterior curvature of the pelvic floor was also compared. Normality of all variables was assessed by Shapiro-Wilk test. RESULTS: The largest amount of surface-to-surface distance was observed in the proximal region for the urethra and rectum. Across all three organs, the majority of the deviation was in the anterior direction for geometries obtained from ultrasound versus those from MRI. For each subject, the trace defining the midline of the levator plate was more anterior for ultrasound compared to MRI. CONCLUSIONS: While it has often been assumed that placing a probe in the vagina probably distorts the anatomy, this study quantified the distortion and displacement of the pelvic viscera. This allows for better interpretation of clinical and research findings based on this modality.

8.
Biomech Model Mechanobiol ; 22(3): 1083-1094, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36862346

RESUMO

Composites comprising crimped fibers of finite length embedded in a soft matrix have the potential to mimic the strain-hardening behavior of tissues containing fibrous collagen. Unlike continuous fiber composites, such chopped fiber composites would be flow-processable. Here, we study the fundamental mechanics of stress transfer between a single crimped fiber and the embedding matrix subjected to tensile strain. Finite element simulations show that fibers with large crimp amplitude and large relative modulus straighten significantly at small strain without bearing significant load. At large strain, they become taut and hence bear increasing load. Analogous to straight fiber composites, there is a region near the ends of each fiber which bears much lower stress than the midsection. We show that the stress-transfer mechanics can be captured by a shear lag model where the crimped fiber can be replaced with an equivalent straight fiber whose effective modulus is lower than that of the crimped fiber, but increases with applied strain. This allows estimating the modulus of a composite at low fiber fraction. The degree of strain hardening and the strain needed for strain hardening can be tuned by changing relative modulus of the fibers and the crimp geometry.


Assuntos
Colágeno , Estresse Mecânico
9.
Urogynecology (Phila) ; 29(9): 740-747, 2023 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-36946905

RESUMO

IMPORTANCE: In the past, urethral shape, mobility, and urodynamics have been used to retrospectively demonstrate correlations with stress urinary incontinence. Our previous work has shown a relationship between urethral function and shape in symptomatic women. OBJECTIVE: This study aimed to characterize the effect of pelvic floor squeeze and strain maneuvers on urethral shapes and pressure in a cohort of patients without pelvic floor disorders. STUDY DESIGN: In this cross-sectional study, volunteers underwent dynamic pelvic floor ultrasound examination, and a modified urodynamic study. Urethral length, thickness, and proximal and distal swing angles were measured at rest, squeeze, and strain. The midsagittal urethral walls were traced so that a statistical shape model could be performed. Means and standard deviations of imaging and urodynamic measures were calculated. RESULTS: Data from 19 participants were analyzed. On average during squeeze compared with rest, urethral length increased by 6%, thickness decreased by 42% (distal, P < 0.001), 10% (middle), and urethral pressure increased by 14%. Opposite shape changes-length decreased by 10% ( P = 0.001), thickness increased by 57% (distal, P < 0.001), 20% (middle, P < 0.001)-and increased urethral mobility were observed during strain, with larger pressure increases occurring (29%, P < 0.001). Fifty-one percent of the total shape variance described the differences between maneuvers. These differences were statistically different between groups ( P < 0.001 for comparisons, all others P > 0.05). CONCLUSIONS: Dynamic ultrasound and urodynamics allow for the establishment of baseline ranges in urethral metrics (2-dimensional measures, shape, and pressure) and how they are altered during maneuvers. These data can allow for a more objective identification of incontinence via ultrasound and urodynamic testing.


Assuntos
Tosse , Incontinência Urinária por Estresse , Humanos , Feminino , Estudos Transversais , Estudos Retrospectivos , Incontinência Urinária por Estresse/diagnóstico por imagem , Uretra/diagnóstico por imagem
10.
Int Urogynecol J ; 34(7): 1627-1633, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36656345

RESUMO

INTRODUCTION AND HYPOTHESIS: Measurements of levator bowl volume using advanced imaging, may be predictive of pelvic floor muscle function. The aim of this study was to compare the volume of the levator bowl using both magnetic resonance imaging (MRI) and endovaginal ultrasound (EVU) of healthy asymptomatic women. METHODS: All participants underwent a comprehensive interview including completion of the Pelvic Floor Distress Inventory Questionnaire-20 questionnaire, pelvic examination with a pelvic organ prolapse quantification evaluation, MRI, and EVU. The pelvic floor was segmented using Slicer and the MRI segmentations were trimmed using two methods: soft-tissue landmarks and the field of view (FOV) of the ultrasound volume. The levator bowl volume of the 3D segmented shapes was measured using Blender's 3D printing toolkit. Normality was tested using the Shapiro-Wilks test and comparisons were made using self-paired t tests. RESULTS: The final analysis included 19 patients. Levator bowl volume measured via MRI was larger than that measured in EVU (46.1 ± 7.9 cm3 vs 27.4 ± 5.9 cm3, p<0.001). Reducing the FOV of the MRI to that of EVU caused the MRI volume to be much closer to the EVU volume (35.5 ± 3.3 cm3 vs 27.4 ± 5.9 cm3, p<0.001); however, it remained significantly larger. CONCLUSION: Levator bowl volume measured using MRI was larger than that measured using EVU no matter the method of delineation of the levator muscles. Although EVU is safe, cheap, and easy to perform, it captures a smaller volume of levator bowel than MRI.


Assuntos
Imageamento Tridimensional , Prolapso de Órgão Pélvico , Humanos , Feminino , Imageamento Tridimensional/métodos , Prolapso de Órgão Pélvico/diagnóstico , Ultrassonografia , Imageamento por Ressonância Magnética , Diafragma da Pelve
11.
Ann Biomed Eng ; 51(7): 1461-1470, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36715838

RESUMO

Specific levator ani muscle imaging measures change with pregnancy and vaginal parity, though entire pelvic floor muscle complex (PFMC) shape variation related to pregnancy-induced and postpartum remodeling has never been quantified. We used statistical shape modeling to compute the 3D variation in PFMC morphology of reproductive-aged nulliparous, late pregnant, and parous women. Pelvic magnetic resonance images were collected retrospectively and PFMCs were segmented. Modes of variation and principal component scores, generated via statistical shape modeling, defined significant morphological variation. Nulliparous (have never given birth), late pregnant (3rd trimester), and parous (have given birth and not currently pregnant) PFMCs were compared via MANCOVA. The overall PFMC shape, mode 2, and mode 3 significantly differed across patient groups (p < 0.001, = 0.002, = 0.001, respectively). This statistical shape analysis described greater perineal and external anal sphincter descent, increased iliococcygeus concavity, and a proportionally wider mid-posterior levator hiatus in late pregnant compared to nulliparous and parous women. The late pregnant group was the most divergent, highlighting differences that likely reduce the mechanical burden of vaginal childbirth. This robust quantification of PFMC shape provides insight to pregnancy and postpartum remodeling and allows for generation of representative non-patient-specific PFMCs that can be used in biomechanical simulations.


Assuntos
Parto , Diafragma da Pelve , Gravidez , Humanos , Feminino , Adulto , Paridade , Diafragma da Pelve/diagnóstico por imagem , Diafragma da Pelve/fisiologia , Estudos Retrospectivos , Parto Obstétrico
12.
Int Urogynecol J ; 34(2): 535-543, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35794274

RESUMO

INTRODUCTION AND HYPOTHESIS: Pelvic organ prolapse (POP) is often diagnosed during an in-office examination, which looks for motion of the vaginal wall while performing a strain maneuver. It is believed that the pelvic organs in adequately supported women are relatively stationary. This study was aimed at investigating the physiological displacements of pelvic organs using MR defecography. METHODS: This prospective cohort study included 19 volunteers. Midsagittal slices representing rest and the maximum movement of the posterior vaginal fornix during three maneuvers were identified. Normalized axes for analysis were defined as the x' (line connecting the inferior-posterior-most point on the pubic symphysis to the anterior edge of the sacrococcygeal joint) and the y' (line orthogonal to the x axis that passed through the sacral promontory). The positions of the posterior vaginal fornix, mid-vagina, bladder neck, anorectal junction, and hymen were recorded. These subjects were then analyzed using the current radiological grading system of POP to determine any overlap between asymptomatic subjects and diagnostic ranges of POP. RESULTS: Evacuation caused the most motion in the landmarks. The majority of the motion of the landmarks was along the y axis. The posterior vaginal fornix experienced significant descent (125% of the initial distance) without much anterior-posterior translation (7% of the initial distance) during defecation. All landmarks experienced similar trends. CONCLUSIONS: We have shown that there is significant rotational motion of the pelvic organs around the pubic bone in adequately supported women. This motion when described using radiological grading is likely to be considered mild or moderate prolapse, which may contribute to overdiagnosis of POP.


Assuntos
Prolapso de Órgão Pélvico , Vísceras , Feminino , Humanos , Estudos Prospectivos , Prolapso de Órgão Pélvico/diagnóstico , Vagina , Diafragma da Pelve
13.
J Biomech Eng ; 145(1)2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-35900843

RESUMO

Computational modeling serves an important role in childbirth-related research. Prescribed fetal descent trajectory is a key characteristic in childbirth simulations. Two major types of fully prescribed fetal descent trajectories can be identified in the literature: straight descent trajectories and curve of Carus. The straight descent trajectory has the advantage of being simpler and can serve as a reasonable approximation for relatively small fetal movements during labor, but it cannot be used to simulate the entire childbirth process. The curve of Carus is the well-recognized fetal descent trajectory with physiological significance. However, no detailed procedure to geometrically define the curve of Carus can be found in existing computational studies. This status of curve of Carus simulation in the literature hinders the direct comparison of results across different studies and the advancement of computational techniques built upon previous research. The goals of this study are: (1) propose a universal approach to derive the curve of Carus for the second stage of labor, from the point when the fetal head engages the pelvis to the point when the fetal head is fully delivered; and (2) demonstrate its utility when considering various fetal head sizes. The current study provides a detailed formulation of the curve of Carus, considering geometries of both the mother and the fetus. The maternal geometries were obtained from MRI data, and the fetal head geometries were based on laser scanning of a replica of a real fetal head.


Assuntos
Parto Obstétrico , Parto , Simulação por Computador , Parto Obstétrico/métodos , Feminino , Feto/fisiologia , Cabeça , Humanos , Parto/fisiologia , Gravidez
16.
Int Urogynecol J ; 33(6): 1649-1657, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35394140

RESUMO

INTRODUCTION AND HYPOTHESIS: We present a 3D computational approach for automated clitoral measurements. We hypothesized that computationally derived measurements would be comparable and less variable than reported manual measures. METHODS: In this retrospective study, MRIs of 22 nulliparous women age 20-49 years with normal vaginal and clitoral anatomy were collected. Manual segmentations were performed to reconstruct 3D models of the whole clitoris (glans, body, crura, and bulbs) and vagina. The length, width, and volume of the clitoral structures and the distance between the vagina and clitoral structures were calculated. Computed clitoral morphometrics (length, width) were compared to median [range] values from a previously published cadaver study (N = 22) using the median test and Moses extreme reaction test. Calculated distances were compared to mean (± SD) reported by a 2D MRI study (N = 20) using independent t-test and Levene's test. RESULTS: Overall, computed clitoral morphometrics were similar to manual cadaver measurements, where the majority of length and width measures had ~1-2 mm difference and had less variability (smaller range). All calculated distances were significantly smaller and had smaller SDs than manual 2D MRI values, with two-fold differences in the means and SDs. Large variation was observed in clitoral volumetric measures in our cohort. CONCLUSIONS: The proposed 3D computational method improves the standardization and consistency of clitoral measurements compared to traditional manual approaches. The use of this approach in radiographic studies will give better insight into how clitoral anatomy relates to sexual function and how both are impacted by gynecologic surgery, where outcomes can assist treatment planning.


Assuntos
Clitóris , Imageamento por Ressonância Magnética , Adulto , Cadáver , Clitóris/anatomia & histologia , Clitóris/diagnóstico por imagem , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Vagina , Adulto Jovem
17.
Ann Biomed Eng ; 50(4): 440-451, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35182248

RESUMO

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.


Assuntos
Contração Muscular , Músculo Liso , Animais , Feminino , Contração Muscular/fisiologia , Músculo Liso/fisiologia , Ratos , Bexiga Urinária , Vagina/patologia
18.
Int Urogynecol J ; 33(3): 541-550, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33822259

RESUMO

INTRODUCTION AND HYPOTHESIS: Urethral closure mechanism dysfunction in female stress urinary incontinence (SUI) is poorly understood. We aimed to quantify these mechanisms through changes in urethral shape and position during squeeze (voluntary closure) and Valsalva (passive closure) via endovaginal ultrasound in women with varying SUI severity. METHODS: In this prospective cohort study, 76 women who presented to our tertiary center for urodynamic testing as preoperative assessment were recruited. Urodynamics were performed according to International Continence Society criteria. Urethral pressures were obtained during serial Valsalva maneuvers. Urethral lengths, thicknesses, and angles were measured in the midsagittal plane via dynamic anterior compartment ultrasound. Statistical shape modeling was carried out by a principal component analysis on aligned urethra shapes. RESULTS: Age, parity, and BMI did not vary by SUI group. Ultrasound detected a larger retropubic angle, urethral knee-pubic bone angle (a novel measure developed for this study), and infrapubic urethral length measurements at Valsalva in women with severe SUI (p = 0.016, 0.015, and 0.010). Shape analysis defined increased "c" shape concavity and distal wall pinching during squeeze and increased "s" shape concavity and distal wall thickening during Valsalva (p < 0.001). It also described significant urethral shape differences across SUI severity groups (p < 0.001). CONCLUSIONS: Dynamic endovaginal ultrasound can visualize and allow for quantification of voluntary and passive urethral closure and variations with SUI severity. In women with severe SUI, excessive bladder neck and distal urethra swinging during Valsalva longitudinally compressed the urethra, resulting in a proportionally thicker wall at the mid-urethra and urethral knee.


Assuntos
Uretra , Incontinência Urinária por Estresse , Feminino , Humanos , Gravidez , Estudos Prospectivos , Uretra/diagnóstico por imagem , Bexiga Urinária , Incontinência Urinária por Estresse/cirurgia , Urodinâmica
19.
Int Urogynecol J ; 33(2): 327-335, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33860812

RESUMO

INTRODUCTION AND HYPOTHESIS: We compared the impact of a mesh manufactured from the soft elastomer polydimethylsiloxane (PDMS) to that of a widely used lightweight polypropylene (PP) mesh. To achieve a similar overall device stiffness between meshes, the PDMS mesh was made with more material and therefore was heavier and less porous. We hypothesized that the soft polymer PDMS mesh, despite having more material, would have a similar impact on the vagina as the PP mesh. METHODS: PDMS and PP meshes were implanted onto the vaginas of 20 rabbits via colpopexy. Ten rabbits served as sham. At 12 weeks, mesh-vagina complexes were explanted and assessed for contractile function, histomorphology, total collagen, and glycosaminoglycan content. Outcome measures were compared using one-way ANOVA and Kruskal-Wallis testing with appropriate post-hoc testing. RESULTS: Relative to sham, vaginal contractility was reduced following the implantation of PP (p = 0.035) but not the softer PDMS (p = 0.495). PP had an overall greater negative impact on total collagen and glycosaminoglycan content, decreasing by 53% (p < 0.001) and 54% (p < 0.001) compared to reductions of 35% (p = 0.004 and p < 0.001) with PDMS. However, there were no significant differences in the contractility, collagen fiber thickness, total collagen, and glycosaminoglycan content between the two meshes. CONCLUSIONS: Despite having a substantially higher weight, PDMS had a similar impact on the vagina compared to a low-weight PP mesh, implicating soft polymers as potential alternatives to PP. The notion that heavyweight meshes are associated with a worse host response is not applicable when comparing across materials.


Assuntos
Prolapso de Órgão Pélvico , Polipropilenos , Animais , Elastômeros , Feminino , Humanos , Prolapso de Órgão Pélvico/cirurgia , Coelhos , Telas Cirúrgicas , Vagina/cirurgia
20.
Int Urogynecol J ; 33(3): 551-561, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33787951

RESUMO

INTRODUCTION AND HYPOTHESIS: In Part 1, we observed urethral mechanics during Valsalva that oppose current continence theories. In this study, we utilize a finite element model to elucidate the role of supportive tissues on the urethra during Valsalva. By determining the sensitivity of urethral motion and deformations to variations in tissue stiffnesses, we formulate new hypotheses regarding mechanisms of urethral passive closure. METHODS: Anatomy was segmented from a nulliparous, continent woman at rest. The model was tuned such that urethral motion during Valsalva matched that observed in that patient. Urethra and surrounding tissue material properties were varied using Latin hypercube sampling to perform a sensitivity analysis. As in Part 1, urethral length, proximal and distal swinging, and shape parameters were measured at peak Valsalva for 50 simulations, and partial rank correlation coefficients were calculated between all model inputs and outputs. Cumulative influence factors determined which tissue properties were meaningfully influential (≥ 0.5). RESULTS: The material properties of the urethra, perineal membrane, bladder, and paraurethral connective tissues meaningfully influenced urethral motion, deformation, and shape. Reduction of the urethral stiffness and/or the perineal membrane soft constraint resulted in simulated urethral motions and shapes associated with stress urinary incontinence in Part 1. CONCLUSIONS: The data from Parts 1 and 2 suggest that connective tissues guide the controlled swinging motion and deformation of the urethra needed for passive closure during Valsalva. The swinging and kinking quantified in Part 1 and simulated in Part 2 are inconsistent with current continence theories.


Assuntos
Uretra , Incontinência Urinária por Estresse , Feminino , Humanos , Masculino , Bexiga Urinária , Urodinâmica , Manobra de Valsalva
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