The correlation of urethral resistance pressure with maximum urethral closure pressure and stress incontinence

Biomechanical study of the male lower urinary tract: Simulation of internal and external sphincters dyssynergia

Urethral sphincter dysfunction is an important cause of stress urinary incontinence (SUI). The most effective treatment is the insertion of an artificial urethral sphincter (AUS), which relies to a large extent on the surgeon's experience. However, there is no quantitative standard for cuff tightness, resulting in frequent postoperative complications. This study aimed to investigate the effect of internal and external sphincter dyssynergia on urodynamic parameters in the lower urinary tract. A geometric model of male lower urinary tract tissue was constructed from collodion slices, accounting for the active behavior of the internal and external sphincters. Normal and dyssynergic internal and external sphincters (active sphincter behavior was individually injured by 25%, 50%, 75%, or 100%) were simulated with fluid-structure interactions and changes in urethral stress, displacement, and urine flow rate were detected. We found that when the internal sphincter was injured by 25%, 50%, 75%, and 100%, urethral stress near the internal sphincter decreased by 8.3%, 15.6%, 24.3%, and 35.7%, respectively. Additionally, when the external sphincter was injured by 25%, 50%, 75%, and 100%, urethral stress near the external sphincter was reduced by 13.3%, 24.3%, 38.6%, and 46.6%, respectively. Internal sphincter injury primarily affects positions near the internal sphincter and prostate, while external sphincter injury affects the area between the prostate and urethral outlet. These data could facilitate the standardized evaluation of internal and external sphincter dysfunction and lead to novel methods of preoperative assessment for AUS surgery.

Correlations between severity of anterior vaginal wall prolapse and parameters of urethral pressure profile

OBJECTIVE

Previous studies have shown that anterior vaginal wall prolapse (AVWP) results in reduction of pressure in the proximal urethra. However, the effect of severity of AVWP on urethral pressure is controversial. This study aimed to evaluate parameters of the urethral pressure profile in different stages of AVWP.

MATERIALS AND METHODS

From 2016 to 2017, 286 consecutive patients with urogynecologic complaints who were referred to our urodynamic unit were enrolled in this study to analyze their urethral pressure profiles. Stages of AVWP were regrouped into three groups ranging from mild to severe stages (groups 1-3). Maximal urethral pressure, urethral closure pressure, functional urethral length, length of continence zone, as well as area of continence zone were compared among these three groups.

RESULTS

Distribution of age, parity, and menopausal women were significantly different among these three groups. Maximal urethral pressure (pressures for groups 1, 2, and 3 were 74.6∼75.9cmH2O, 69.7∼73.4cmH2O, and 58.3∼60.5cmH2O, respectively; all P<.05) and stress urethral closure pressure (pressures for groups 1, 2, and 3 were 69.3cmH2O, 62.3cmH2O, and 52.2cmH2O, respectively; all P<.05) gradually and significantly decreased, consistent with the severity of AVWP. However, the attenuated maximal urethral pressure and stress urethral closure pressure in accordance with severity did not show any significant difference after controlling for age, body mass index, parity, menopause, and stress urinary incontinence symptoms.

CONCLUSION

Our results showed that AVWP significantly attenuated urethral pressure. However, patient age, menopausal status, and number of parities seem to be more influential in compromising urethral function than just AVWP alone.

The pathophysiology of stress urinary incontinence: a systematic review and meta-analysis

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.

Persistent and recurrent stress urinary incontinence following mid-urethral tape surgery in women: a UK perspective

Stress urinary incontinence is a common health problem that affects a large proportion of women in Britain. It poses physical and psychological implications for the affected women and is a frequent indication for referral to tertiary urology centres. Midurethral tape surgery (MUTS) has established itself as the standard first-line surgical treatment as a result of its low morbidity, short hospital stay and high long-term success. Failure of the initial surgery can present as persistent or recurrent symptoms. This is a major challenge to the treating urologists as a result of the complicated nature of the condition and the lack of strong evidence supporting individual treatment modalities. In this article we discuss the factors associated with MUTS failure and the surgical options for its treatment.

Urodynamics in the management of female stress incontinence--which test and when?

PURPOSE OF REVIEW

This article reviews the literature from the last 12 months in the context of our existing knowledge base and reviews the contentious issue of the role of preoperative urodynamics for stress urinary incontinence, with particular reference to the choice of urodynamic investigations for diagnostic differentiation between intrinsic sphincter deficiency and urethral hypermobility, assessing symptom severity and predicting postoperative prognosis.

RECENT FINDINGS

While there are significant conflicting data regarding the role of urodynamics, particularly in the functional assessment of the urethra, it is clear that these diagnostic techniques can provide clinically useful data. It is in this context that recent guidelines advising on restricted use of invasive urodynamics preoperatively should be carefully reviewed.

SUMMARY

There is a pressing need for randomized controlled trials to be performed to fully assess the role of urodynamics in the preoperative assessment of stress urinary incontinence, especially at this time of rapid change in the surgical treatments available.