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Annals of the New York Academy of... Apr 2007The anatomic structures in the female that prevent incontinence and genital organ prolapse on increases in abdominal pressure during daily activities include sphincteric... (Review)
Review
The anatomic structures in the female that prevent incontinence and genital organ prolapse on increases in abdominal pressure during daily activities include sphincteric and supportive systems. In the urethra, the action of the vesical neck and urethral sphincteric mechanisms maintains urethral closure pressure above bladder pressure. Decreases in the number of striated muscle fibers of the sphincter occur with age and parity. A supportive hammock under the urethra and vesical neck provides a firm backstop against which the urethra is compressed during increases in abdominal pressure to maintain urethral closure pressures above the rapidly increasing bladder pressure. This supporting layer consists of the anterior vaginal wall and the connective tissue that attaches it to the pelvic bones through the pubovaginal portion of the levator ani muscle, and the uterosacral and cardinal ligaments comprising the tendinous arch of the pelvic fascia. At rest the levator ani maintains closure of the urogenital hiatus. They are additionally recruited to maintain hiatal closure in the face of inertial loads related to visceral accelerations as well as abdominal pressurization in daily activities involving recruitment of the abdominal wall musculature and diaphragm. Vaginal birth is associated with an increased risk of levator ani defects, as well as genital organ prolapse and urinary incontinence. Computer models indicate that vaginal birth places the levator ani under tissue stretch ratios of up to 3.3 and the pudendal nerve under strains of up to 33%, respectively. Research is needed to better identify the pathomechanics of these conditions.
Topics: Biomechanical Phenomena; Female; Humans; Pelvic Floor; Urethra
PubMed: 17416924
DOI: 10.1196/annals.1389.034 -
International Urogynecology Journal Mar 2021To evaluate the evidence for pathologies underlying stress urinary incontinence (SUI) in women. (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION AND HYPOTHESIS
To evaluate the evidence for pathologies underlying stress urinary incontinence (SUI) in women.
METHODS
For the data sources, a structured search of the peer-reviewed literature (English language; 1960-April 2020) was conducted using predefined key terms in PubMed and Embase. Google Scholar was also searched. Peer-reviewed manuscripts that reported on anatomical, physiological or functional differences between females with signs and/or symptoms consistent with SUI and a concurrently recruited control group of continent females without any substantive urogynecological symptoms. Of 4629 publications screened, 84 met the inclusion criteria and were retained, among which 24 were included in meta-analyses.
RESULTS
Selection bias was moderate to high; < 25% of studies controlled for major confounding variables for SUI (e.g., age, BMI and parity). There was a lack of standardization of methods among studies, and several measurement issues were identified. Results were synthesized qualitatively, and, where possible, random-effects meta-analyses were conducted. Deficits in urethral and bladder neck structure and support, neuromuscular and mechanical function of the striated urethral sphincter (SUS) and levator ani muscles all appear to be associated with SUI. Meta-analyses showed that observed bladder neck dilation and lower functional urethral length, bladder neck support and maximum urethral closure pressures are strong characteristic signs of SUI.
CONCLUSION
The pathology of SUI is multifactorial, with strong evidence pointing to bladder neck and urethral incompetence. While there is also evidence of impaired urethral support and levator ani function, standardized approaches to measurement are needed to generate higher levels of evidence.
Topics: Female; Humans; Parity; Pelvic Floor; Pregnancy; Urethra; Urinary Bladder; Urinary Incontinence, Stress
PubMed: 33416968
DOI: 10.1007/s00192-020-04622-9 -
Journal of Robotic Surgery Feb 2023The objective of the study was to test the impact of implementing standard full functional-length urethral sphincter (FFLU) and neurovascular bundle preservation (NVBP)...
The objective of the study was to test the impact of implementing standard full functional-length urethral sphincter (FFLU) and neurovascular bundle preservation (NVBP) with intraoperative frozen section technique (IFT) on long-term urinary continence in patients undergoing robotic-assisted radical prostatectomy (RARP). We relied on an institutional tertiary-care database to identify patients who underwent RARP between 01/2014 and 09/2019. Until 10/2017, FFLU was not performed and decision for NVBP was taken without IFT. From 11/2017, FFLU and IFT-guided NVBP was routinely performed in all patients undergoing RARP. Long-term continence (≥ 12 months) was defined as the usage of no or one safety- pad. Uni- and multivariable logistic regression models tested the correlation between surgical approach (standard vs FFLU + NVBP) and long-term continence. Covariates consisted of age, body mass index, prostate volume and extraprostatic extension of tumor. The study cohort consisted of 142 patients, with equally sized groups for standard vs FFLU + NVBP RARP (68 vs 74 patients). Routine FFLU + NVBP implementation resulted in a long-term continence rate of 91%, compared to 63% in standard RARP (p < 0.001). Following FFLU + NVBP RARP, 5% needed 1-2, 4% 3-5 pads/24 h and no patient (0%) suffered severe long-term incontinence (> 5 pads/24 h). No significant differences in patient or tumor characteristics were recorded between both groups. In multivariable logistic regression models, FFLU + NVBP was a robust predictor for continence (Odds ratio [OR]: 7.62; 95% CI 2.51-27.36; p < 0.001). Implementation of FFLU and NVBP in patients undergoing RARP results in improved long-term continence rates of 91%.
Topics: Male; Humans; Prostate; Urethra; Robotic Surgical Procedures; Treatment Outcome; Prostatectomy; Prostatic Neoplasms; Recovery of Function
PubMed: 35459985
DOI: 10.1007/s11701-022-01408-7 -
Ugeskrift For Laeger Apr 2023This review summarises the principles for diagnosing and treating acute urological trauma. Renal trauma can be life threatening, although most injuries are... (Review)
Review
This review summarises the principles for diagnosing and treating acute urological trauma. Renal trauma can be life threatening, although most injuries are self-limiting. Development in imaging and non-operative measures allows for a more conservative and nephron-sparing approach. Pelvic fracture urethral injury is often associated with multiple injuries. Strategy for intervention depends on whether the injury is partial or complete, anterior or posterior. Penile fracture is a rare but acute urological condition. Surgical treatment is necessary to minimize risk of complications. If handled accordingly, the functional outcome is good.
Topics: Humans; Urethra; Urethral Diseases; Fractures, Bone; Multiple Trauma; Kidney
PubMed: 37057693
DOI: No ID Found -
Physiological Reports Jan 2021To confirm changes in urethral activity with age, both intravesical pressure and urethral perfusion pressure (UPP) were recorded and external urethral sphincter...
To confirm changes in urethral activity with age, both intravesical pressure and urethral perfusion pressure (UPP) were recorded and external urethral sphincter electromyography (EUS-EMG) was performed. A total of 33 female Sprague Dawley rats aged 3 months (young rats), 12 months (middle-aged rats), and 24 months (aged rats) were used. Bladder activity was evaluated using continuous cystometry. Urethral activity was evaluated by simultaneously recording intravesical pressure and UPP in isovolumetric conditions under urethane anesthesia in each group. Additionally, EUS-EMG activity was monitored under the same conditions. In continuous cystometry, the amplitude of bladder contractions was not different among the three groups; nevertheless, residual urine volume was significantly increased in middle-aged and aged rats, as compared in young rats. With respect to UPP, the change in UPP was significantly smaller in aged rats (60%) and middle-aged rats (64%) than in young rats. Furthermore, the mean amplitude of high-frequency oscillations of the EUS was significantly lower in aged (61%) and middle-aged rats (70%) than in young rats. EUS-EMG revealed EUS bursting activity during voiding with clear active and silent phases in young rats but unclear active and silent phases in aged rats. Masson's trichrome staining of the urethra showed EUS atrophy in aged rats compared to young and middle-aged rats. The results indicate that aging induces two urethral dysfunctions in the urethral smooth muscle and EUS, which may lead to dyscoordination between the urinary bladder and urethra.
Topics: Aging; Animals; Female; Muscle Contraction; Muscle, Smooth; Rats; Rats, Sprague-Dawley; Urethra; Urinary Bladder; Urinary Bladder, Underactive
PubMed: 33356016
DOI: 10.14814/phy2.14643 -
Autonomic Neuroscience : Basic &... Nov 2021The storage and elimination of urine requires coordinated activity between muscles of the bladder and the urethra. This coordination is orchestrated by a complex system... (Review)
Review
The storage and elimination of urine requires coordinated activity between muscles of the bladder and the urethra. This coordination is orchestrated by a complex system containing spinal, midbrain and forebrain networks. Normally there is a reciprocity between patterns of activity in urinary bladder sacral parasympathetic efferents and somatic motoneurons innervating the striatal external urethral sphincter muscle. At the spinal level this reciprocity is mediated by ensembles of excitatory and inhibitory interneurons located in the lumbar-sacral segments. In this review I will present an overview of currently identified spinal interneurons and circuits relevant to the lower urinary tract and will discuss their established or hypothetical roles in the cycle of micturition. In addition, a recently discovered auxiliary spinal neuronal ensemble named lumbar spinal coordinating center will be described. Sexual dimorphism and developmental features of the lower urinary tract which may play a significant role in designing treatments for patients with urine storage and voiding dysfunctions are also considered. Spinal cord injuries seriously damage or even eliminate the ability to urinate. Treatment of this abnormality requires detailed knowledge of supporting neural mechanisms, therefore various experiments in normal and spinalized animals will be discussed. Finally, a possible intraspinal mechanism will be proposed for organization of external urethral sphincter (EUS) bursting which represents a form of intermittent EUS relaxation in rats and mice.
Topics: Animals; Humans; Interneurons; Male; Mice; Motor Neurons; Rats; Spinal Cord; Spinal Cord Injuries; Urethra; Urinary Bladder; Urination
PubMed: 34391124
DOI: 10.1016/j.autneu.2021.102861 -
Stem Cells and Development Feb 2020Stress urinary incontinence (SUI) after prostate surgery is primarily caused by urethral sphincter damage. There are few effective therapeutic approaches for male SUI...
Stress urinary incontinence (SUI) after prostate surgery is primarily caused by urethral sphincter damage. There are few effective therapeutic approaches for male SUI due to both insufficient study of the structure of the external urethral sphincter (EUS) and incomplete understanding of the resident EUS stem/progenitor cells. The goals of this study were to localize and to determine the distribution of tissue-resident stem/progenitor cells in the male EUS throughout EUS development and to understand the anatomic temporal patterns of the EUS. Newborn Sprague Dawley rats were intraperitoneally injected with the thymidine analogue, 5-ethynyl-2-deoxyuridine (EdU), and the EUS was harvested at five time points (1, 2, 3, 4, and 8 weeks postinjection). The tissue was then processed for EdU staining and immunofluorescence staining for stem cell markers Ki67 and proliferating cell nuclear antigen. We counted the EdU+ label-retaining cells (LRCs) at each time point and colocalized with each stem cell marker, also we isolated and cultured the cells in vitro. The results revealed that the number of EdU+ LRCs in each EUS cross-section decreased over time and that the LRCs were located immediately under the basal membrane of laminin, densely adherent to the muscle fibers. In addition, the thickness of the striated muscle layer developed much faster than the smooth muscle layer during EUS development. By 4 weeks, the structure of the EUS layers was well differentiated. The EUS resident stem/progenitor cells were isolated with MACS MicroBeads system, and myogenesis was confirmed. In this study, we defined both the time-course development of the EUS and the distribution of resident stem/progenitor cells. This information is crucial for forthcoming studies regarding male micturition and for development of novel therapeutic approaches for postoperative male SUI.
Topics: Adult Stem Cells; Animals; Cell Self Renewal; Cells, Cultured; Male; Muscle Development; Rats; Rats, Sprague-Dawley; Urethra
PubMed: 31822215
DOI: 10.1089/scd.2019.0241 -
Neurourology and Urodynamics Nov 2021A critical appraisal of the literature regarding female urethral function and dysfunction is needed in light of recent evidence showing the urethra's role in causing... (Review)
Review
INTRODUCTION
A critical appraisal of the literature regarding female urethral function and dysfunction is needed in light of recent evidence showing the urethra's role in causing stress and urge urinary incontinence.
METHODS
An evidence assessment was conducted using selected articles from the literature that contained mechanistic data on factors affecting urethral function and failure.
RESULTS
Maximal urethral closure pressure (MUCP) is 40% lower in stress urinary incontinence (SUI) than normal controls. Evidence from five women shows relatively equal contributions to MUCP from striated/smooth muscle, vascular-plexus, connective tissue. MUCP varies twofold in individuals of similar age and declines 15% per decade even in nulliparous women. Age explains 57% of the variance in MUCP. This parallels with striated/smooth muscle loss and reduced nerve density. Factors influencing pressure variation minute-to-minute and decade-to-decade are poorly understood. Connective tissue changes have not been investigated. MUCP in de novo SUI persisting 9-months postpartum is 25% less than in age and parity-matched controls. Longitudinal studies do not show significant changes in urethral function after vaginal birth suggesting that changes in urethral support from birth may unmask pre-existing sphincter weakness and precipitate SUI. Mechanisms of interaction between support injury, pre-existing urethral weakness, and neuropathy are unclear.
CONCLUSION
Urethral failure is the predominant cause of SUI and a contributing factor for UUI; potentially explaining why mixed symptoms predominate in epidemiological studies. Age-related striated muscle loss and differences between women of similar age are prominent features of poor urethral closure. Yet, connective tissue changes, vasculature function, and complex interactions among factors are poorly understood.
Topics: Female; Humans; Muscle, Smooth; Pregnancy; Urethra; Urinary Incontinence, Stress; Urinary Incontinence, Urge; Vagina
PubMed: 34488242
DOI: 10.1002/nau.24760 -
Neurourology and Urodynamics Feb 2016Urethral pathophysiology is often neglected in discussions of bladder dysfunction. It has been debated whether "urethral sphincter instability," referred to based on... (Review)
Review
AIMS
Urethral pathophysiology is often neglected in discussions of bladder dysfunction. It has been debated whether "urethral sphincter instability," referred to based on observed "urethral pressure variations," is an important aspect of overactive bladder syndrome (OAB). The purpose of this report is to summarize current urethral pathophysiology evidence and outline directions for future research based on a literature review and discussions during the ICI-RS meeting in Bristol in 2014.
METHODS
Urethral pathophysiology with a focus on urethral pressure variation (UPV) was presented and discussed in a multidisciplinary think tank session at the ICI_R meeting in Bristol 2014. This think tank session was based on collaboration between physicians and basic science researchers.
RESULTS
Experimental animal studies or studies performed in clinical series (predominantly symptomatic women) provided insights into UPV, but the findings were inconsistent and incomplete. However, UPV is certainly associated with lower urinary tract symptoms (likely OAB), and thus, future research on this topic is relevant.
CONCLUSIONS
Future research based on adequately defined clinical (and urodynamic) parameters with precisely defined patient groups might shed better light on the cause of OAB symptoms. Further fundamental investigation of urethral epithelial-neural interactions via the release of mediators should enhance our knowledge and improve the management of patients with OAB.
Topics: Animals; Humans; Lower Urinary Tract Symptoms; Pressure; Prognosis; Risk Factors; Urethra; Urinary Bladder; Urinary Bladder, Overactive; Urodynamics
PubMed: 26872575
DOI: 10.1002/nau.22815 -
Neurourology and Urodynamics Nov 2011The Sprague-Dawley (SD) rat, an out-bred, all-purpose strain, has served well for lower urinary tract research. However, to test new cellular therapies for conditions... (Comparative Study)
Comparative Study
AIMS
The Sprague-Dawley (SD) rat, an out-bred, all-purpose strain, has served well for lower urinary tract research. However, to test new cellular therapies for conditions such as stress urinary incontinence, an in-bred rat strain with immune tolerance, such as the Lewis rat, may be more useful. The objective of this study was to reveal any differences in lower urinary tract continence mechanisms between the Lewis and SD rat.
METHODS
The contribution of (1) the striated and smooth muscle to the mechanical and functional properties of the urethra in vitro, and (2) the striated sphincter to leak point pressure (LPP) and reflex continence mechanisms in vivo were assessed in normal (control) Lewis and SD rats and in a model of stress urinary incontinence produced by bilateral pudendal nerve transection.
RESULTS
Control, Lewis rats had significantly lower LPP, significantly less fast-twitch skeletal muscle and relied less on the striated sphincter for continence than control, SD rats, as indicated by the failure of neuromuscular blockade with alpha-bungarotoxin to reduce LPP. Nerve transection significantly decreased LPP in the SD rat, but not in the Lewis rat. Although the Lewis urethra contained more smooth muscle than the SD rat, it was less active in vitro as indicated by a low urethral baseline pressure and lack of response to phenylephrine.
CONCLUSIONS
We have observed distinct differences in functional and mechanical properties of the SD and Lewis urethra and have shown that the Lewis rat may not be suitable as a chronic model of SUI via nerve transection.
Topics: Acetylcholine; Animals; Biomechanical Phenomena; Bungarotoxins; Disease Models, Animal; Female; Phenylephrine; Pressure; Pudendal Nerve; Rats; Rats, Inbred Lew; Rats, Sprague-Dawley; Reflex; Sneezing; Species Specificity; Urethra; Urinary Incontinence; Urodynamics
PubMed: 21826722
DOI: 10.1002/nau.21158