The need for standardization of the valsalva leak-point pressure

An Overview of the Effect of Aging on the Female Urethra

Urethral function declines by roughly 15% per decade and profoundly contributes to the pathogenesis of urinary incontinence. Individuals with poor urethral function are more likely to fail surgical management for stress incontinence that focus on improving urethral support. The reduced number of intramuscular nerves and the morphologic changes in muscle and connective tissue collectively impact urethral function as women age. Imaging technologies like MRI and ultrasound have advanced our understanding of these changes. However, substantial knowledge gaps remain. Addressing these gaps can be crucial for developing better prevention and treatment strategies, ultimately enhancing the quality of life for aging women.

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.

Accuracy of methods for urinary detection in women with stress urinary incontinence

Purpose

We assessed the accuracy of urinary detection by visualization compared with a method using the urethral channel of a transurethral, three-channel urodynamic catheter.

Materials and Methods

This was a case series of 52 patients presenting with stress urinary incontinence over 2 years. Patients underwent video-urodynamic studies in both the supine and the erect positions by use of two techniques for measuring leak point pressure (LPP) by one examiner. LPP was determined as the intravesical pressure simultaneous to the starting point of urethral pressure changes through the urethral channel of a urodynamic catheter (LPP-ure) and then by visualization (LPP-vis) during different events. We also measured the time related to the provocations and the time to mark the leakage on the urodynamic machine by the examiner.

Results

The LPP-ure values (cough supine: 42.1±18.7, cough erect: 42.1±21.8, Valsalva supine: 42.2±23.3, Valsalva erect: 41.0±22.6 cmH₂O) were significantly lower than the LPP-vis values (89.9±29.4, 97.4±30.4, 70.6±25.2, and 74.4±32.6 cmH₂O, respectively, all p<0.001). Whereas the actual leakages happened during the pressure increases, urodynamic recording by visualization was done after those increases had finished.

Conclusions

The use of visualization as a urinary detection method entails potential errors that cannot be adjusted for on that time scale. Our results emphasize the need to standardize the methodologies used for urinary leakage detection, because this measurement is closely related to the accuracy of measurement of leak point pressure.

Is it possible to diagnose intrinsic sphincter deficiency in women?

PURPOSE OF REVIEW

The diagnosis of intrinsic sphincter deficiency became important about 20 years ago when it influenced the choice of operative procedure for women with stress urinary incontinence. However, it was ill-defined and diagnosed by a variety of techniques. The contemporary surgical treatment of urinary stress incontinence is by suburethral sling; so this review addresses three questions: is it still important to identify intrinsic sphincter deficiency prior to surgical intervention for stress incontinence? What techniques are available to do so? How robust are these measurements?

RECENT FINDINGS

There is some evidence that women with intrinsic sphincter deficiency have a poorer outcome if they are treated by a transobturator tape compared with a tension-free vaginal tape or a pubovaginal sling. Intrinsic sphincter deficiency continues to be mainly identified by low urethral closure pressures or low abdominal leak point pressures or both but the methodology is variable. There have been some attempts at using ultrasound to identify intrinsic sphincter deficiency but without any definite conclusions.

SUMMARY

Intrinsic sphincter deficiency is an imprecise diagnosis, which continues to be defined by a low pressure urethra. This can be measured in different ways but there is poor standardization of the tests to do so. Intrinsic sphincter deficiency appears to be clinically important but the full implications of this diagnosis will remain unknown until this imprecision is addressed.

Weak VLPP and MUCP correlation and their relationship with objective and subjective measures of severity of urinary incontinence

The aims of the present study were to find the correlation between Valsalva leak-point pressure (VLPP) and cough leak-point pressure (CLPP) and to determine whether the water perfusion maximum urethral closure pressure (MUCP) correlates with VLPP. Seventy-nine women with previously untreated stress urinary incontinence were recruited to participate in a clinical study. Their mean age was 56.4 years, mean BMI was 27.8, and mean parity was 1.9. The mean values of VLPP and CLPP were 50.4 and 52.9 cm H(2)O, respectively. We did not find statistically significant differences in the mean values of VLPP and CLPP. The mean value of MUCP at rest was 44.2 cm H(2)O and the mean value of MUCP during maximal Valsalva maneuver was 37.2 cm H(2)O; with 500 ml of sterile saline in the bladder the difference between them is statistically significant. In the study group (n=79), 56 patients (77%) had low VLPP (< or =60 cm H(2)O), 21 patients (30%) had low MUCP (< or =30 cm H(2)O), and 8 patients had MUCP< or =20 cm H(2)O (all at rest). Of the 56 patients with low VLPP, 16 also had a low MUCP (< or =30 cm H(2)O). This study mainly compares two parameters-the MUCP and the VLPP. Based on our results we can conclude that there is no correlation between these parameters. MUCP measures urethral resistance at rest and VLPP measures urethral resistance during increased intra-abdominal pressure (Valsalva maneuver).

A multicentered comparison of measurements obtained with microtip and external water pressure transducers

This study compared simultaneous intravesical pressure readings obtained with catheter-mounted microtip transducers and external water pressure transducer catheters during filling cystometry. Women undergoing multichannel urodynamic testing were randomly assigned to one of three groups: two microtip catheters, two external water pressure transducer catheters, or one of each type. Intravesical pressure was measured simultaneously for each transducer combination in each subject for minimal and maximal Valsalva effort and minimal, moderate, and maximal cough effort at two sequential bladder volumes (150 and 300 ml). Paired t tests were used to compare the means of the intravesical pressure obtained by the two types of catheters. The largest mean differences were observed when comparing microtip and water pressure transducers. Correlations of maximum pressure were consistently high between two microtip transducers and two water pressure transducers but lower for the microtip-water combination. Excellent reproducibility was demonstrated with transducers of similar types for intravesical pressures recorded during Valsalva and cough in women without prolapse. However, considerable variability was seen in pressures recorded by different transducers, particularly dependent on the water catheter manufacturer, indicating that intravesical pressure recordings from microtip and water-based systems are not interchangeable.

Comparison of measurements obtained with microtip and external water pressure transducers

The aim of this study was to compare pressure readings obtained with catheter-mounted microtip and external water pressure transducers using a mechanical model for vesical pressure during Valsalva straining and coughing. The two catheter-mounted pressure transducers were simultaneously placed in a vinyl i.v. bag designed to mimic the parameters of the human bladder to allow comparison of simultaneous readings from both transducers. Simulated cough and Valsalva maneuvers of various strengths at different volumes (100 ml, 200 ml, 300 ml) were performed and the pressure readings generated by the two systems compared. The Pearson correlation coefficient between the systems was 0.998 for coughs and 0.998 for Valsalva efforts. Data were also analyzed by volume and strength of simulated cough and Valsalva effort, and correlations were found to be high (> or = 0.940) for all subgroup analyses. Mean absolute differences between events recorded by the two systems were small, as indicated by the y-intercept of 3.76 cmH2O pressure. Neither transducer recorded consistently higher pressures than the other. We concluded that there is a high correlation between pressure measurements obtained from microtip and external water pressure transducers during simulated cough and Valsalva efforts in this model. As similar correlation should exist in vivo, urodynamic data generated by the two transducer types should be comparable.

Evaluation of minimally invasive analysis system for cough leak point pressure measurement

PURPOSE

Leak point pressure (LPP) measurement has become standard in the diagnosis of stress urinary incontinence. Leak point pressure is determined by increasing abdominal pressure, which can be done with a Valsalva maneuver or coughing, that is Valsalva LPP and cough LPP (CLPP). It may be influenced by catheter size, bladder volume and interobserver variability. A new, computerized LPP measuring technique for routine use in daily urodynamic practice was tested at a female unit urodynamic practice to evaluate female urinary incontinence.

MATERIALS AND METHODS

A total of 28 female patients with a mean age of 54.07 years (range 23 to 82) and urinary incontinence underwent a new, minimally invasive measurement of the cough leak point. Measurements are made with the patient standing and repeated 3 times per patient. Additionally, parameters of the corresponding leak were recorded simultaneously. All patients underwent new CLPP measurement and a standard, complete urodynamic investigation, including filling cystometry with abdominal LPP and urethral pressure profile at rest. Statistical evaluation was done by linear regression analysis and the correlation coefficients among CLPP, age, standard abdominal LPP and maximum urethral pressure, and among the 3 measurements for each patient.

RESULTS

: The assignment of leakage to the pressure signal presented no problem. All CLPP data were reproducible in the 3 repeated measurements per patient. No correlation was seen between CLPP and abdominal LPP or the urethral pressure profile.

CONCLUSIONS

The study confirm that the CLPP is a practicable, consistent and minimally invasive method in routine use. Clinical use is easy and reproducible, and only 1 catheter is required for measurement.

Baseline abdominal pressure and valsalva leak point pressures-correlation with clinical and urodynamic data

AIMS

To characterize the factors contributing to changes in baseline abdominal pressure (P(abd)) and the correlation between DeltaVLPP, VLPP(tot), and other clinical and urodynamic variables.

METHODS

Two hundred sixty-four female patients who had undergone an anti-incontinence procedure between February 1994 and October 1999 were retrospectively reviewed. The urodynamics performed for each patient included abdominal and vesical pressures measured in a standardized manner with the patient sitting upright and the pressure sensors maintained at the level of the symphysis pubis. VLPP was determined at bladder volumes of 200 mL during a gradually increasing Valsalva maneuver.

RESULTS

Baseline P(abd) varied between 10 and 55 cm H(2)O (mean, 32.7 +/- 8.8) and were significantly correlated with patient weight (P<0.001) and with patient body mass index (P<0.001). Baseline P(abd) was not found to be correlated with patient age, Baden and Walker Classification of the grading of pelvic floor prolapse, degree of incontinence (determined by the number of pads used per day), or prior surgical procedures for stress incontinence. Higher baseline P(abd) were significantly correlated with the peak abdominal pressure reached during the Valsalva maneuver (P<0.0001) and with VLPP(tot) (P<0.0001) but not with DeltaVLPP. Higher VLPP(tot) significantly correlated with decreased age (P=0.004), less severe incontinence (P=0.004), higher peak Valsalva pressure (P<0.0001), and the ability to increase abdominal pressure for a longer period of time (time to peak P(abd) during Valsalva). VLPP(tot) and DeltaVLPP had similar statistical correlation with all the clinical variables examined and neither could predict the outcome of any anti-incontinence surgery. By using a VLPP of 60 cm H(2)O as a cutoff to differentiate severe ISD from GSUI, 211 (67.4%) of the patients would be categorized as having ISD according to their DeltaVLPP compared with only 106 (40.1%) by using the VLPP(tot).

CONCLUSIONS

Baseline P(abd) varies considerably among patients, is correlated with patient weight and habitus. In addition, it varies with both the ability to be increased for longer periods of time and with VLPP(tot). Looking at VLPP(tot) and DeltaVLPP will result in a different categorization of the type of incontinence in at least 25% of patients and, thus, affect the physician's selection of an anti-incontinence procedure for an individual patient.

Observations on the function of the female urethra: III: An overview with special reference to the relation between urethral hypermobility and urethral incompetence

AIMS

To analyze the relation between urethral hypermobility and urethral incompetence, and to summarize the interdependence between maximum urethral closure pressure (MUCP), urethral hypermobility, and urethral incompetence.

PATIENTS AND METHODS

A group of 255 patients was selected from a large bank of cases. Inclusion criteria were age 20 years or above, no neurological disease, stable bladder, and no previous incontinence surgery or hysterectomy. The degree of hypermobility (cysto-urethrocele) and the degree of urethral incompetence (abdominal leak point pressure (ALPP)) were determined. Statistical analyses between urethral hypermobility and incompetence were performed with Spearman's correlation and the Jonckherre-Terpstra test.

RESULTS

The Spearman's rank correlation test showed a statistically significant relation between urethral hypermobility and the degree of urethral incompetence (P = 0.0049).

CONCLUSIONS

The statistically significant relation between urethral incompetence and hypermobility suggests that urethral incompetence will increase as the degree of urethral hypermobility does. Optimal conditions for urinary continence include a high maximum urethral closure pressure, absence of hypermobility, and a low degree of urethral incompetence. This last factor is assured by a strong support underneath the urethra permitting compression of the latter during straining. Failure of the urethral closure mechanism is highly probable with a diminished maximum closure pressure accompanied by urethral hypermobility often associated with a high degree of urethral incompetence. Clinically significant urinary incontinence may appear in many intermediate circumstances between these two extreme states, but stress urinary incontinence is essentially an activity-related phenomenon.