Urethral pressure variations in healthy females during rest and sleep

The female urethra: urethral function throughout a woman's lifetime

INTRODUCTION AND HYPOTHESIS

The objective of this narrative review is to describe changes in urethral function that occur during a woman's lifetime. Evaluation of urethral function includes measurements of urethral closure pressure, at rest and during stress, leak point pressure, and the detailed study of anatomical and histological changes of the urethral sphincteric mechanism.

METHODS

A literature search in MEDLINE, PubMed, and relevant journals from 1960 until 2020 was performed for articles dealing with urethral function and the impact of aging, pregnancy, and childbirth, female hormones, and menopausal transition on the urethral sphincteric mechanism. Longitudinal and cross-sectional epidemiological surveys, studies on histological changes in urethral anatomy during aging, and urodynamic data obtained at different points in a woman's lifetime, during pregnancy, after childbirth, as well as the effects of female hormones on urethral sphincter function are reviewed. Relevant studies presenting objective data are analyzed and briefly summarized.

RESULTS AND CONCLUSIONS

The findings lead one to conclude that a constitutional or genetic predisposition, aging, and senescence are the most prominent etiological factors in the development of urinary incontinence and other pelvic floor disorders. Vaginal childbirth dilates and may damage the compressed pelvic supportive tissues and is invariably associated with a decline in urethral sphincter function. Pregnancy, hormonal alterations, menopausal transition, weight gain, and obesity are at best of secondary influence on the pathology of lower urinary tract dysfunction. The decline of circulating estrogens during menopausal transition may play a role in the transition of fibroblasts to cellular senescence.

Urgency and urgency incontinence following stress urinary incontinence surgery: A review of evaluation and management

The presence of urgency urinary incontinence (U/UUI) after sling surgery is a common reason for dissatisfaction and imposition on quality of life. We aimed to evaluate and analyze the pathophysiology, evaluation, and treatment of U/UUI after sling surgery. A MEDLINE review was performed for relevant, English-language articles relating to storage and emptying symptoms after sling surgery. U/UUI may persist, be improved, or worsen in women with preoperative mixed urinary incontinence and may appear de novo in those women originally presenting with pure stress urinary incontinence (SUI). While the exact mechanism is not clear, partial bladder outlet obstruction (BOO) should always be suspected, especially in those women with worsened or de novo symptoms soon after sling surgery. Initial workup should elucidate the temporality, quality, and bother associated with symptoms and to evaluate the woman for urinary tract infection (UTI), pelvic organ prolapse (POP), or perforation of the lower urinary tract. The utility of urodynamics in attaining a definitive diagnosis of BOO is inconclusive. Treatment options include reevaluation of the patient after sling incision or after addressing UTI, POP, and perforation of the bladder or urethra. Women also typically undergo a multitiered approach to storage lower urinary tract symptoms outlined in the American Urological Association/Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction Overactive Bladder Guidelines. While improvement is typically seen with multimodality treatment, all women should be counseled regarding need for additional treatment for U/UUI, BOO, and SUI in the future.

Continuous urethral pressure measurements; measurement techniques; pressure variations; clinical interpretations; and clinical relevance. A Systematic Literature Analysis

AIMS

The clinical relevance of urethral pressure variations (UPV) in the pathophysiology of over active bladder syndrome (OAB) has remained controversial to date. Some studies report an association with OAB and/or detrusor over activity (DO). Recently the International Consultation on Incontinence-Research Society recommended new clinical research to be performed on this subject. We provide a systematic review of the literature to specify this recommendation.

METHODS

Literature search was performed in PubMed, Embase, Web of Science, Cochrane, Central, Cinahl, Academic Science Premier, Science Direct, and Wiley Online using a sensitive search string combination. All authors independently reviewed and scored full text papers and consensus about methodological quality was obtained according to Oxford Level of Evidence (LoE).

RESULTS

Four hundred eighty seven abstracts were screened, 25 papers met all predefined inclusion selection criteria. Incidence figures of UPV varied between 2% and 95%. Studies are of poor methodological quality with Oxford LoE scores of 3B and 4. Measurement methods and techniques show a large variety. The above mentioned association of DO/OAB with UPV is however frequently reported.

CONCLUSION

There exists a phenomenon of UPV, apart from DO, which may be a separate entity within OAB syndrome. Large variation in measurement techniques and patient populations hinders fundamental research as well as clinical progress. Clinical relevance of UPV and consequences for treatment therefore are yet to be established. Future prospective research with well-defined patient population and standardised urodynamic measurement techniques is needed. Results of standardized and objective evaluations should be compared to clinical signs and symptoms by validated questionnaires. Neurourol. Urodynam. 36:51-56, 2017. © 2015 Wiley Periodicals, Inc.

The impact of detrusor overactivity on the management of stress urinary incontinence in women

The presence of overactive bladder symptoms, urodynamic detrusor overactivity, and urge incontinence can complicate the diagnosis and management of stress urinary incontinence in women. The exact pathophysiology of mixed incontinence is not well characterized; in some patients, the stress and urge etiology may be pathologically linked. The role of urodynamics in evaluating patients with mixed incontinence remains controversial. Conservative therapies, such as bladder training, pelvic floor exercise, biofeedback, and electrical stimulation, offer moderate success in women with mixed incontinence. Surgery (colposuspension, bladder neck pubovaginal slings, and midurethral slings) offers excellent subjective and objective cure rates in patients with mixed incontinence. Preoperative detrusor overactivity is cured consistently 50%of the time with colposuspension and slings. Overall, the presence of preoperative detrusor overactivity does not appear to significantly worsen the outcome of conservative and surgical treatments for stress urinary incontinence in women.

Reduction in nocturnal functional bladder capacity is a common factor in the pathogenesis of refractory nocturnal enuresis

OBJECTIVE

To evaluate the diurnal and nocturnal bladder reservoir function in patients with refractory primary nocturnal enuresis (PNE).

PATIENTS AND METHODS

Ninety-five children (68 boys, 27 girls, mean age 9.3 years) with significant PNE (>/=3 wet nights/week) that was refractory to treatment with desmopressin +/- an enuretic alarm were assessed using detailed recording of voiding frequency and urinary volume both day and night, natural filling cystometry during the day and continuous cystometry with simultaneous electroencephalogram monitoring during sleep at night.

RESULTS

Patients could be broadly categorized into two groups. Group A comprised those with normal daytime urodynamics and functional bladder capacity (FBC) on detailed frequency-volume recording, but who developed marked detrusor instability associated with a significant reduction in nocturnal FBC and small-volume voiding only after sleep at night (33 patients, 35%); and group B, those with abnormal daytime urodynamics and with reduced FBC and small-volume voiding both day and night, but who somehow managed to mask their bladder symptoms during the day (62 patients, 65%). There was no evidence of nocturnal polyuria in either group and the ratios of day : night urinary output volumes for type A and type B patients were 1.48 and 1.99, respectively.

CONCLUSION

A reduction in nocturnal FBC, either occurring only after sleep at night in association with the appearance of detrusor instability in patients with normal daytime urodynamics and FBC, or as a manifestation of occult voiding dysfunction or bladder outlet obstruction that affects the bladder reservoir function both day and night, appears to be a common factor and probably the main cause for a mismatch between nocturnal urine output and bladder storage capacity in patients with severe bed-wetting that was refractory to treatment.

In vivo evaluation of visco-elasticity in a biological tube. Part 1. Stress relaxation in the female urethra studied by cross-sectional area and pressure measurements

The urethral response to a sudden forced dilatation was studied by a mathematical analysis of the pressure response in ten healthy women. A total of 60 dilatations, using various sizes and velocities of deformation, were performed in the high-pressure zone. The decay in pressure during relaxation proved to follow an exponential equation of the following form: Y = Z + C alpha e-t/tau alpha + C beta e-t/tau beta, where Z is the equilibrium pressure, C alpha and C beta are pressure decay, and T alpha and T beta are time constants. The time constants were unaffected by the circumstances of dilatation, whereas all the other parameters were correlated to size or velocity of dilatation, or both. The time constants showed a fairly high reproducibility when repeated after one weak. The method is presumed to characterise the tissue composition of the periluminal tissue layers and may prove useful in the evaluation of the normal urethral sphincter function. Furthermore, it may prove of value in the elucidation of the pathophysiology of stress urinary incontinence.

Urethral pressure variation in women with vulvar vestibulitis syndrome

OBJECTIVES

It is hypothesized that patients with vulvar vestibulitis syndrome will demonstrate increased urethral pressure variability.

STUDY DESIGN

Twelve patients with confirmed vulvar vestibulitis syndrome were compared with two groups: 13 patients with chronic pelvic pain matched for age and race and 23 asymptomatic unmatched patients. Urodynamic variables studied included maximum urethral pressure, functional urethral length, bladder capacity, and urethral pressure variability. During urethral pressure measurement each patient was given a standard mental exercise.

RESULTS

Urethral pressure variability was significantly greater in patients with vulvar vestibulitis than in those with chronic pain or in asymptomatic controls (Wilcoxon test, p < 0.001). Use of a multiple regression model that controlled for age, race, and parity showed that diagnostic group predicted a significant degree of urethral pressure variability (F = 8.18, p < 0.001).

CONCLUSIONS

Vulvar vestibulitis syndrome is associated with increased urethral pressure variability, and variation in muscular tone of the urethra is the probable source of this variability. However, the possible relationship with the pathogenesis of vulvar vestibulitis syndrome is unknown at present.

Urethral pressure and pressure variations in healthy fertile and postmenopausal women with reference to the female sex hormones

The impact of female sex hormones on the rhythmic urethral pressure variations (UPV) was analysed based on data from one hour urethral pressure recordings from 10 healthy fertile female volunteers measured three times during the menstrual cycle and from 12 healthy postmenopausal women measured twice within two months. The mean maximum urethral pressure (mMUP) and the mean maximum urethral closure pressure (mMUCP) had a median value of 66.5 (Interquartile 58.0-86.0) and 60.0 (49.0-80.0) cm.H2O respectively in the healthy fertile females. The postmenopausal women had a significantly lower mMUP and mMUCP of 55.5 (48.5-58.5) and 43.5 (35.5-47.0) cm.H2O) respectively. Rhythmic UPV was recorded inhealthy fertile and postmenopausal women. Frequency analysis of the UPV revealed a frequency spectrum from 0.0015 to 0.035 Hz on top of which were respiration fluctuations and vascular pulsations. The UPV amplitude was related to the mMUP and increased with increasing mMUP. The parameters analysed were stable during the menstrual cycle and during menopause. Thus no difference in the UPV frequencies or amplitudes was observed between the healthy fertile and the postmenopausal women. The investigation shows that the pressure variation in urethra apparently is not modulated by female sex hormones.