The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform
John O.l. Delancey - One of the best experts on this subject based on the ideXlab platform.
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a multi compartment 3 d finite element model of rectocele and its interaction with cystocele
Journal of Biomechanics, 2015Co-Authors: Luyun Chen, Dee E. Fenner, James A Ashtonmiller, John O.l. DelanceyAbstract:We developed a subject-specific 3-D finite element model to understand the mechanics underlying formation of female pelvic organ prolapse, specifically a rectocele and its interaction with a cystocele. The model was created from MRI 3-D geometry of a healthy 45 year-old multiparous woman. It included anterior and posterior vaginal walls, levator ani muscle, cardinal and uterosacral ligaments, anterior and posterior arcus tendineus fascia pelvis, arcus tendineus levator ani, Perineal body, Perineal Membrane and anal sphincter. Material properties were mostly from the literature. Tissue impairment was modeled as decreased tissue stiffness based on previous clinical studies. Model equations were solved using Abaqus v 6.11. The sensitivity of anterior and posterior vaginal wall geometry was calculated for different combinations tissue impairments under increasing intraabdominal pressure. Prolapse size was reported as pelvic organ prolapse quantification system (POP-Q) point at point Bp for rectocele and point Ba for cystocele. Results show that a rectocele resulted from impairments of the levator ani and posterior compartment support. For 20% levator and 85% posterior support impairments, simulated rectocele size (at POP-Q point: Bp) increased 0.29 mm/cm H2O without apical impairment and 0.36 mm/cm H2O with 60% apical impairment, as intraabdominal pressures increased from 0 to 150 cm H2O. Apical support impairment could result in the development of either a cystocele or rectocele. Simulated repair of posterior compartment support decreased rectocele but increased a preexisting cystocele. We conclude that development of rectocele and cystocele depend on the presence of anterior, posterior, levator and/or or apical support impairments, as well as the interaction of the prolapse with the opposing compartment.
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Anatomy of the Perineal Membrane as seen in magnetic resonance images of nulliparous women
American Journal of Obstetrics and Gynecology, 2009Co-Authors: Catherine Brandon, Kindra A Larson, Christina Lewicky-gaupp, John O.l. DelanceyAbstract:Objective Recent cadaver research demonstrates the Perineal Membrane's ventral and dorsal portions and close relationship to the levator ani muscle. This study seeks to show these relationships in women by magnetic resonance (MR) images. Study Design The subjects were 20 asymptomatic nulliparous women with normal pelvic examinations. MR images were acquired in multiple planes. Anatomical relationships from cadaver studies were examined in these planes. Results In the coronal plane the ventral Perineal Membrane forms an interconnected complex with the compressor urethrae, vestibular bulb, and levator ani. The dorsal part connects the levator ani and vaginal side wall via a distinct band to the ischiopubic ramus. In the sagittal plane the parallel position of Perineal Membrane and levator ani are seen. Conclusion The Perineal Membrane's anatomical features can be seen in women with MR. The close relationship between the Perineal Membrane and levator ani is evident.
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Anatomy of the Perineal Membrane as seen in magnetic resonance images of nulliparous women.
American journal of obstetrics and gynecology, 2009Co-Authors: Catherine J Brandon, Christina Lewicky-gaupp, Kindra A Larson, John O.l. DelanceyAbstract:Recent cadaver research demonstrates the Perineal Membrane's ventral and dorsal portions and close relationship to the levator ani muscle. This study seeks to show these relationships in women by magnetic resonance (MR) images. The subjects were 20 asymptomatic nulliparous women with normal pelvic examinations. MR images were acquired in multiple planes. Anatomical relationships from cadaver studies were examined in these planes. In the coronal plane the ventral Perineal Membrane forms an interconnected complex with the compressor urethrae, vestibular bulb, and levator ani. The dorsal part connects the levator ani and vaginal side wall via a distinct band to the ischiopubic ramus. In the sagittal plane the parallel position of Perineal Membrane and levator ani are seen. The Perineal Membrane's anatomical features can be seen in women with MR. The close relationship between the Perineal Membrane and levator ani is evident.
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structure of the Perineal Membrane in females gross and microscopic anatomy
Obstetrics & Gynecology, 2008Co-Authors: Tamara Stein, John O.l. DelanceyAbstract:OBJECTIVE: To re-examine the anatomy of the Perineal Membrane and its anatomical relationships in whole-pelvis and histologic serial section as well as gross anatomical dissection. METHODS: Serial trichrome-stained histologic sections of five female pelvic specimens (0-37 years old) were examined. Specimens included the urethra, Perineal Membrane, vagina, and surrounding structures. Macroscopic whole-pelvis sections of three adults, 28-56 years of age, in axial, sagittal, and coronal sections were also studied. Dissections of six female cadavers, 48-90 years of age, were also performed. RESULTS: The Perineal Membrane is composed of two regions, one dorsal and one ventral. The dorsal portion consists of bilateral transverse fibrous sheets that attach the lateral wall of the vagina and Perineal body to the ischiopubic ramus. This portion is devoid of striated muscle. The ventral portion is part of a solid three-dimensional tissue mass in which several structures are embedded. It is intimately associated with the compressor urethrae and the urethrovaginal sphincter muscle of the distal urethra with the urethra and its surrounding connective. In this region the Perineal Membrane is continuous with the insertion of the arcus tendineus fascia pelvis. The levator ani muscles are connected with the cranial surface of the Perineal Membrane. The vestibular bulb and clitoral crus are fused with the Membrane's caudal surface. CONCLUSION: The structure of the Perineal Membrane is a complex three-dimensional structure with two distinctly different dorsal and ventral regions; not a simple trilaminar sheet with perforating viscera.
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The axial location of structural regions in the urethra: a magnetic resonance study in nulliparous women.
Obstetrics and gynecology, 2003Co-Authors: Wolfgang H Umek, Rohna Kearney, Daniel M Morgan, James A Ashton-miller, John O.l. DelanceyAbstract:To define and quantify the appearance and location of distinct regions of the bladder neck and urethra by using axial magnetic resonance images from healthy, continent, nulliparous women. Seventy-eight asymptomatic, healthy, nulliparous women (mean age 29.2 +/- 5.4 years) volunteered for this study. All women were proven continent on urodynamic examination. Axial proton density magnetic resonance images of the pelvic floor were analyzed at 5-mm intervals. A geometric origin was established at the internal urethral meatus. The presence or absence of each of six structural regions--the bladder base, bladder neck, striated urethral sphincter, compressor urethrae and urethrovaginal sphincter, Perineal Membrane, and distal urethra--was then noted in each more distal image. The proportion of women in whom a structural region was seen at each 5-mm interval was recorded. The striated urogenital sphincter was observed at 5-25 mm distal to the bladder base. It was observed 10 and 15 mm below the bladder base in 91% (95% confidence interval [CI] 85%, 98%) and 99% (95% CI 97%, 100%), respectively, of all women. The Perineal Membrane, marking the distal end of the muscular urethra, was located 20-35 mm distal to the bladder base. The length of the muscular region of the urethra ranged from 20 to 35 mm (mean 24 mm, 95% CI 24, 25 mm). Magnetic resonance images allow the normal appearance and location of urethral and bladder neck structures to be quantified in healthy, continent, nulliparous women.
Jean De Leval - One of the best experts on this subject based on the ideXlab platform.
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transobturator vaginal tape inside out for the surgical treatment of female stress urinary incontinence anatomical considerations
The Journal of Urology, 2005Co-Authors: Pierre Bonnet, David Waltregny, Olivier Reul, Jean De LevalAbstract:Purpose: We have recently described a novel surgical technique for female stress urinary incontinence, that is the transobturator vaginal tape inside out, which uses specific instruments for the passage of a synthetic tape from beneath the urethra toward the thigh folds. Herein we report the results of cadaver dissection performed to determine the anatomical trajectory of the tape and its relationships with neighboring neurovascular structures and organs. Materials and Methods: Insertion of the transobturator vaginal tape inside out tape was performed by different surgeons in 12 freshly frozen female cadavers according to the standard procedure. The thigh, obturator, Perineal and pelvic regions were dissected and tape trajectory was recorded. An additional cadaver was dissected without prior tape placement. Results: The tape was inserted according to a certain consistent path, that is penetration from the suburethral space into a strictly Perineal region limited medial and cranial by the levator ani muscle, caudal by the Perineal Membrane and lateral by the obturator internus muscle. This region corresponded to the most anterior recess of the ischiorectal fossa. The tape then perforated the obturator Membrane and muscles, and exited through the skin after traversing adductor muscles and subcutaneous tissue. The tape was coursed away from 1) the dorsal nerve to the clitoris located more superficially below the Perineal Membrane, 2) the obturator nerve and vessels, and 3) the saphenous and femoral vessels. Conclusions: These findings strongly suggest that our transobturator technique is highly accurate, reproducible and safe, and it does not require perioperative cystoscopy.
Richard A Santucci - One of the best experts on this subject based on the ideXlab platform.
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siu icud consultation on urethral strictures pelvic fracture urethral injuries
Urology, 2014Co-Authors: R. Gomez, Tony Mundy, Deepak Dubey, Abdel Wahab Elkassaby, Ron Kodama, Richard A SantucciAbstract:The posterior urethra pierces the Perineal diaphragm in close relationship to the pubic arc elements of the bony pelvis to which it is tethered by attachments to the puboprostatic ligaments and the Perineal Membrane. Because of these relationships, it is not surprising that fracture disruptions of the pelvic ring can be associated with injuries to the urethra at this level. Although the relationship between pelvic fracture and posterior urethral injury has been recognized for >1 century, considerable controversy exists on almost any aspect of these injuries, from the anatomy and classification of the injuries to the strategies for acute management, reconstruction, and treatment of complications, to mention just a few. What it is not controversial and well known is that these injuries can result in significant morbidity in the long run—mainly strictures, erectile dysfunction, and urinary incontinence—which can cause lifelong disability. It also well known that, just as in many other areas of trauma, the severity and duration of the complications can be reduced considerably if the injury is diagnosed and treated promptly and efficiently. This chapter summarizes the most relevant published evidence about the management of pelvic fracture urethral injuries. This comprehensive review, performed by an international panel of experts, will provide valuable information and recommendations to help urologists worldwide improve the treatment and outcomes of their injured patients.
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SIU/ICUD Consultation on Urethral Strictures: Pelvic fracture urethral injuries.
Urology, 2014Co-Authors: R. Gomez, Tony Mundy, Deepak Dubey, Ron Kodama, Abdel Wahab El-kassaby, Firdaoessaleh, Richard A SantucciAbstract:The posterior urethra pierces the Perineal diaphragm in close relationship to the pubic arc elements of the bony pelvis to which it is tethered by attachments to the puboprostatic ligaments and the Perineal Membrane. Because of these relationships, it is not surprising that fracture disruptions of the pelvic ring can be associated with injuries to the urethra at this level. Although the relationship between pelvic fracture and posterior urethral injury has been recognized for >1 century, considerable controversy exists on almost any aspect of these injuries, from the anatomy and classification of the injuries to the strategies for acute management, reconstruction, and treatment of complications, to mention just a few. What it is not controversial and well known is that these injuries can result in significant morbidity in the long run—mainly strictures, erectile dysfunction, and urinary incontinence—which can cause lifelong disability. It also well known that, just as in many other areas of trauma, the severity and duration of the complications can be reduced considerably if the injury is diagnosed and treated promptly and efficiently. This chapter summarizes the most relevant published evidence about the management of pelvic fracture urethral injuries. This comprehensive review, performed by an international panel of experts, will provide valuable information and recommendations to help urologists worldwide improve the treatment and outcomes of their injured patients.
Marlene M. Corton - One of the best experts on this subject based on the ideXlab platform.
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anatomy histology and nerve density of clitoris and associated structures clinical applications to vulvar surgery
American Journal of Obstetrics and Gynecology, 2019Co-Authors: Lindsey A Jackson, Adam M Hare, Kelley S Carrick, Jennifer J Hamner, Denise M.o. Ramirez, Marlene M. CortonAbstract:Background A precise understanding of structures comprising the female external genitalia is essential in obstetric and gynecologic practice. Objective To further characterize the anatomy, histology, and nerve density of the clitoris and associated structures, and to provide clinical correlations to vulvar surgery. Materials and Methods Unembalmed female cadavers were examined. The length and width of the body, glans, and crura of the clitoris were measured. Distances from the glans to the urethra and from the dorsal surface of the clitoral body to the mid pubic arch were recorded. The path of the dorsal nerve of the clitoris was examined, and the nerve width was measured as it emerged from the lateral surface of crura and at the distal clitoral body. Distances from where the dorsal nerve emerged from the Perineal Membrane to the posterior surface of the Membrane and to mid pubic arch were measured. Connective tissue layers associated with the clitoris were examined. Tissue was harvested from additional unembalmed cadavers, and nerve density of the labia minora, glans, and clitoral body were analyzed. Histological examination was performed on vulvar structures to clarify tissue composition. Descriptive statistics were used for data analyses. Results A total of 27 cadavers (aged 48–96 years) were examined, 22 grossly and 5 histologically. The median length and width of clitoral body were 29 mm (range, 13–59 mm) and 9 mm (range, 5–14 mm), respectively. The glans was 8 mm (range, 5–12 mm) long and 4 mm (range, 3–10 mm) wide. The length of the crura was 50 mm (range, 25–68 mm), and the width at the anterior portion was 9 mm (range, 2–13 mm). The closest distance from the glans to the urethra was 25 mm (range, 14–37 mm) and from the clitoral body to the mid pubic arch was 29 mm (range, 14–46 mm). The widths of the dorsal nerve at the lateral crura and at the distal clitoral body were 3 mm (range, 2–4 mm) and 1 mm (range, 1–2 mm), respectively. The distance from the dorsal nerve as it emerged from the Perineal Membrane to the mid pubic arch was 34 mm (range, 20–48 mm) and to the posterior surface of the Membrane was 20 mm (range, 8–31 mm). The dorsal nerve and artery of the clitoris coursed adjacent to the medial surface of the inferior pubic ramus surrounded by a dense fibrous capsule adherent to the periosteum. The nerve and artery then coursed deep to dense connective tissue layers, which were contiguous with the suspensory ligament and fascia of the clitoris. Histologic examination revealed the presence of erectile tissue in the clitoral body, crura, and vestibular bulbs, but such tissue was absent in the glans and labia minora. Nerve density analysis revealed statistically significant greater density in the dorsal compared with ventral half of the clitoral body. Although not statistically significant, there was increased nerve density in the distal compared to the proximal half of the labia minora. Conclusion Precise knowledge of clitoral anatomy and associated neurovascular structures is essential to safely complete partial vulvectomies, clitoral and vulvar reconstructive procedures, anti-incontinence surgeries, and repair of obstetric lacerations. Understanding the range of anatomic variations and awareness of the areas of increased nerve density is important during counseling and surgical planning. Although the dorsal nerve of the clitoris courses deep to dense connective tissue layers, inadvertent injury may occur in the setting of deep dissection or suture placement. The dorsal nerve seems most vulnerable with surgical entry or lacerations that extend from the midline of the prepuce to the inferior pubic rami.
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Anatomic relationships of the pudendal nerve branches
American Journal of Obstetrics and Gynecology, 2011Co-Authors: T. Ignacio Montoya, Lewis Calver, Jennifer Prats, Kelley S Carrick, Marlene M. CortonAbstract:Objective: We sought to characterize the distribution of the pudendal nerve branches and to correlate findings with injury risk related to common midurethral sling procedures. Study Design: Dissections were performed in 18 female cadavers. Biopsies were obtained to confirm gross findings by histology. Results: In all dissections, most of the clitoral and Perineal nerves coursed caudal to the ventral portion of the Perineal Membrane. The inferior rectal nerve did not enter the pudendal canal in 44% (n = 8) of specimens. Nerve tissue was confirmed histologically in tissue sampled. Conclusion: The clitoral and Perineal branches of the pudendal nerve should be at low risk of direct nerve injury during midurethral slings and similar procedures as they course caudal to the ventral portion of the Perineal Membrane. The inferior rectal nerve might be at risk of injury during procedures that involve passage of needles through the ischioanal fossa. © 2011 Mosby, Inc.
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Anatomical path of the tension-free vaginal tape: reassessing current teachings.
American journal of obstetrics and gynecology, 2006Co-Authors: David D. Rahn, Spyridon I. Marinis, Joseph I. Schaffer, Marlene M. CortonAbstract:Objective The objective of the study was to revisit the anatomical path of the tension-free vaginal tape and better describe its relationship to the Perineal Membrane and other important anatomic landmarks. Study design Dissections of the anterior Perineal triangle, periurethral, and retropubic spaces were performed in 24 unembalmed female cadavers following placement of the tension-free vaginal tape to identify the sling's relationship to the Perineal Membrane, periurethral muscles, and the arcus tendineus fascia pelvis. Results In 100% of specimens, the device passed cephalad to the Perineal Membrane. The urethrovaginal sphincter muscle was perforated in 2 of the specimens. The sling passed lateral to the arcus tendineus and perforated the pubococcygeus muscle in 6 (25%) of the cadavers. In the remaining 18 (75%) specimens, the mesh was medial to the arcus tendineus and penetrated the periurethral connective tissue. Conclusion The assertion that the tension-free vaginal tape perforates the Perineal Membrane is incorrect.
Pierre Bonnet - One of the best experts on this subject based on the ideXlab platform.
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transobturator vaginal tape inside out for the surgical treatment of female stress urinary incontinence anatomical considerations
The Journal of Urology, 2005Co-Authors: Pierre Bonnet, David Waltregny, Olivier Reul, Jean De LevalAbstract:Purpose: We have recently described a novel surgical technique for female stress urinary incontinence, that is the transobturator vaginal tape inside out, which uses specific instruments for the passage of a synthetic tape from beneath the urethra toward the thigh folds. Herein we report the results of cadaver dissection performed to determine the anatomical trajectory of the tape and its relationships with neighboring neurovascular structures and organs. Materials and Methods: Insertion of the transobturator vaginal tape inside out tape was performed by different surgeons in 12 freshly frozen female cadavers according to the standard procedure. The thigh, obturator, Perineal and pelvic regions were dissected and tape trajectory was recorded. An additional cadaver was dissected without prior tape placement. Results: The tape was inserted according to a certain consistent path, that is penetration from the suburethral space into a strictly Perineal region limited medial and cranial by the levator ani muscle, caudal by the Perineal Membrane and lateral by the obturator internus muscle. This region corresponded to the most anterior recess of the ischiorectal fossa. The tape then perforated the obturator Membrane and muscles, and exited through the skin after traversing adductor muscles and subcutaneous tissue. The tape was coursed away from 1) the dorsal nerve to the clitoris located more superficially below the Perineal Membrane, 2) the obturator nerve and vessels, and 3) the saphenous and femoral vessels. Conclusions: These findings strongly suggest that our transobturator technique is highly accurate, reproducible and safe, and it does not require perioperative cystoscopy.