Urethral pressure profile in female stress incontinence

The role of preoperative urodynamics in urogynecologic procedures

Urodynamic studies refer to any tests that provide objective information about lower urinary tract function with the goal of evaluating bladder and urethral function. Pre-operative urodynamic testing is commonly performed prior to urogynecologic procedures for urinary incontinence and pelvic organ prolapse. Although the utility of preoperative urodynamics testing before urogynecologic procedures have been challenged in the literature, the preoperative utilization of urodynamic testing in women with complex voiding dysfunction or associated conditions such as prolapse or urethral diverticulum is still considered important for surgical planning and pre-operative counseling.

Static single channel and multichannel water perfusion pressure profilometry in a bench model of a urethra

AIMS

To determine the catheter perfusion and withdrawal rate which generate the most repeatable single (SCPP) and multichannel pressure profilometry (MCPP) profiles in a bench model.

METHODS

A bench model using a urethral substitute was developed in which SCPP and MCPP were performed using the Brown-Wickham method. One single channel and four multichannel catheters were tested using seven withdrawal rates and three perfusion rates. Repeatability was determined using spread of mean profile pressure, cross-correlation, Bland-Altman statistic, and a one-tailed Student's t-statistic. An artificial urinary sphincter (AUS) model was constructed to create a predictable intraluminal profile. MCPP data were used to generate three-dimensional (3D) images of the pressures exerted by the AUS model.

RESULTS

A withdrawal rate of 0.5 mm/sec and perfusion rate 1 ml/min produced the most repeatable SCPP profiles with a spread of mean profile pressure ≤7 cmH(2)O. For MCPP, a 10 F 6-channel catheter using a withdrawal rate of 1 mm/sec and perfusion rate of 1 ml/min produced the most similar profiles (cross-correlation = 0.99). However, the spread of MCPP was large (spread ≤44 cmH(2)O per channel). Nevertheless MCPP was able to consistently demonstrate areas of high pressure as predicted by the AUS model.

CONCLUSIONS

MCPP was not repeatable and is an unreliable measure of urethral pressure. MCPP and 3D images do demonstrate directional differences predicted from the AUS model. These may be of use for qualitative understanding and appreciation of relative relationships if not actual forces within the urethra and have application in understanding urethral function in vivo.

Urethral pressure measurement in stress incontinence: does it help?

INTRODUCTION AND OBJECTIVES

The resting urethral pressure profile (UPP), used for the assessment of women with stress incontinence, is routine in many urodynamic units. It is time- and effort-consuming, and its diagnostic value is controversial, as well as its value in the prediction of outcome of anti-incontinence surgery. Herein, we assessed its value in the prediction of the outcome of surgery.

PATIENTS AND METHODS

Sixty women were randomized to fascial sling or TVT. Urodynamics were performed preoperatively, 6 months and annually thereafter. After filling and voiding cystometry, resting UPP was performed while sitting. Automated catheter pulling, at a rate of 1 mm/s, was adopted. Averaged readings were obtained. Comparison of maximum urethral closure pressure (MUCP) in success and failure, as well as in sling and TVT, was performed, utilizing ANOVA.

RESULTS

Preoperative MUCP and functional urethral length (FUL) were 72.9 +/- 27.9 cmH2O and 2.4 +/- 0.7 cm. At last follow-up, they were 71.1 +/- 20.7 cmH2O and 2.7 +/- 0.7 cm, respectively. The differences between sling and TVT as regards value of MUCP and FUL were not significant. The relationship of the outcome of surgery and UPP parameters showed no statistical difference. No significant effect was shown for the success of surgery, duration of follow-up, and interaction of outcome and time over MUCP (P = 0.82, 0.56 and 0.69, respectively) or FUL (P = 0.82, 0.11 and 0.67, respectively).

CONCLUSION

The routine use of resting UPP has no added value in terms of the prediction of success of incontinence surgery. It does not help with follow-up and adds to the time and cost of the examination.

CORRELATION BETWEEN URETHRAL SPHINCTER ACTIVITY AND VALSALVA LEAK POINT PRESSURE AT DIFFERENT BLADDER DISTENTIONS: REVISITING THE URETHRAL PRESSURE PROFILE

PURPOSE

We determined the correlation between Valsalva leak point pressure (LPP) and the urethral pressure profile (UPP) in urodynamically selected patients with stress urinary incontinence (SUI) as well as the interference of bladder volume on this correlation.

MATERIALS AND METHODS

A total of 450 consecutive women with SUI were clinically evaluated and underwent urodynamic study. Inclusion criteria were urodynamically demonstrable SUI with normal bladder compliance, sensitivity and capacity. Severe pelvic prolapse, detrusor overactivity and a pattern suggestive of obstruction were excluded. Urodynamic study was performed using a 7Fr 4 channel membrane catheter. LPP was determined at mid bladder capacity and UPP was determined at 50 ml, between 200 and 250 ml, and at bladder capacity.

RESULTS

A total of 200 women fulfilled the selection criteria, of whom 30, 114 and 56 had a LPP of 60 or less, between 60 and 120, and greater than 120 cm H2O, respectively. Except for age and the number of pads the 3 groups were well matched in clinical and bladder urodynamic parameters. A progressive correlation of LPP with maximum urethral closure pressure was found when UPP was performed at 50 ml (r = 0.305, p <0.0001), at 250 ml (r = 0.483, p <0.0001) and at maximum bladder filling (r = 0.561, p <0.0001). Urethral functional length did not show a correlation with LPP at a bladder distention of 50 ml (r = 0.117, p = 0.100) or 200 ml (r = 0.167, p = 0.019) but there was a minor correlation at bladder capacity (r = 0.234, p = 0.002).

CONCLUSIONS

There is a significant correlation between maximum urethral closure pressure and LPP. Patients with a LPP of 60 cm H2O or less have a shorter urethral functional length and lower sphincter activity. Patients with SUI have a more remarkable correlation between UPP and Valsalva LPP when UPP is determined after filling the bladder to more than 200 ml.

Changes in urethral function with bladder filling in the presence of urodynamic stress incontinence and detrusor overactivity

OBJECTIVE

The purpose of this study was to assess the effect of detrusor overactivity and bladder filling on urethral function with the use of urethral profilometry.

STUDY DESIGN

Women with symptoms of urinary incontinence were recruited from our urodynamic clinic. All of the women underwent videocystourethrography and urethral pressure profilometry with the bladder empty and then full. The maximum urethral closure pressure, mean urethral pressure, functional urethral length, and pressure transmission ratios for each quartile were analyzed.

RESULTS

Thirty-five women were recruited: 17 women had urodynamic stress incontinence, and 18 women had detrusor overactivity. In women with urodynamic stress incontinence, there was a significant increase in maximum urethral closure pressure and pressure transmission ratios over all quartiles when the bladder was full compared with empty. In women with detrusor overactivity, there was a significant decrease in functional urethral length and pressure transmission ratios in the second and third quartile of the urethral pressure profiles when the bladder was full compared with empty.

CONCLUSION

Decreases in functional urethral length and pressure transmission ratios with bladder filling in those women with detrusor overactivity are at variance with the normal physiologic response to bladder filling, which suggests that urethral function is affected by the presence of abnormal detrusor activity and that the valid assessment of urethral function may not be possible if the detrusor overactivity is not treated.

Clinical and urodynamic features of intrinsic sphincter deficiency

AIMS

A prospective analysis of 92 patients with genuine stress incontinence was performed to identify the clinical and urodynamic features of intrinsic sphincter deficiency (ISD).

METHODS

We divided the patients into two categories: 50 patients affected by pure ISD as they had severe stress incontinence and no urethral mobility; 42 patients suffering from stress urinary incontinence without ISD as they had mild stress incontinence and marked urethral hypermobility. Cystometry was normal in all patients. The presence/absence of ISD was considered the dependent variable and was correlated against the following independent variables: age, vaginal deliveries, menopause, previous urogynecological surgery and/or hysterectomy, supine stress test, irritative and/or obstructive symptoms, Valsalva leak point pressure (VLPP), maximum urethral closure pressure (MUCP), urethral functional length (UFL), and leakage during cystometry.

RESULTS

The statistical analysis showed close correlations between ISD and age (P < 0.001), menopausal status (P < 0.001), previous surgery (P < 0.0001), supine stress test (P < 0.0001), leakage during cystometry (P < 0.001), and UFL (P < 0.01). The VLPP was below the cut-off value (</=60 cm H(2)O) in 70% of ISD patients (P < 0.0001), whereas the MUCP in 50% of ISD patients (P < 0.0001). Multiple logistic analysis showed that lower VLPP, lower MUCP, and previous surgery correlate more significantly with ISD. After backward conditional stepwise logistic regression, the odds ratio of having ISD were VLPP = 2.3, MUCP = 7.7, VLPP + MUCP = 62.8.

CONCLUSIONS

ISD is related to the presence of a more severe clinical picture and case history, but the most significant independent variables are the VLPP and MUCP.

A comparison of urethral pressure profilometry using microtip and double-lumen perfusion catheters in women with genuine stress incontinence

OBJECTIVE

To compare urethral pressure profilometry measurements using microtip transducer and double-lumen perfusion catheters.

DESIGN

Prospective study.

SETTING

Tertiary referral urogynaecology unit.

SAMPLE

Three hundred and ninety two non-pregnant women with various lower urinary tract symptoms.

METHODS

Multichannel urodynamic investigations were performed using double-lumen perfusion catheters with external pressure transducers in 392 women. For those 301 (76.8%) diagnosed as having genuine stress incontinence, an investigation with microtip transducers followed. For data analysis, a mixed-effects model was used to evaluate changes in the urethral profilometry and an approach proposed by Bland and Altman was applied to access agreement between the two techniques.

RESULTS

Of the 301 women with genuine stress incontinence, 272 were eligible for this study. In resting status, the differences between the two techniques were statistically significant (48.9cm H2O vs 73.4cm H2O, P = 0.0001) after adjusting for age. Moreover, the agreement study also confirmed that these two techniques do not agree sufficiently.

CONCLUSION

Maximum urethral closure pressure obtained from the double-lumen catheter was significantly higher than that obtained from the microtip catheter. Use of the double-lumen catheter for the measurement of maximum urethral closure pressure can be considered a reliable technique since its reproducibility is as good as that of the microtip catheter. Therefore, the diagnosis of 'low pressure urethra' will be different between the two techniques.

Is urethral pressure profilometry a useful diagnostic test for stress urinary incontinence?

Urethral pressure profilometry is commonly used as a diagnostic test for stress urinary incontinence. The objective of this article is to review the published literature on urethral pressure profilometry to summarize its usefulness. MEDLINE was used to search the published English literature from 1966 to October 2000 for full-length original research articles on urethral pressure profilometry and stress urinary incontinence in women. Terms related to urethral pressure profilometry are defined consistently but techniques are not standardized, introducing variation in test results. Reproducibility of urethral pressure profilometry parameters is poor, both because of biological variation and variation within the test procedure itself (related in part to lack of standardization). Parameters of urethral pressure profilometry do not distinguish between continent and incontinent women and do not characterize the severity of incontinence or urethral incompetence. It is, therefore, concluded that urethral pressure profilometry is not a useful diagnostic test for stress urinary incontinence in women. Its use in clinical management is not supported by current evidence.

Clinical assessment of urethral sphincter function

Measurements of urethral pressures, such as maximum urethral pressure, are widely believed to have relevance in the management of urinary incontinence despite evidence to the contrary. In this study maximum urethral pressure and the abdominal pressure required to cause stress incontinence were measured in 125 women with stress incontinence. In women the abdominal pressure required to cause stress incontinence was unrelated to maximum urethral pressure. These findings indicate that maximum urethral pressure has little relationship to urethral resistance to abdominal pressure. In the 9 children with myelodysplasia we compared the detrusor pressure with the abdominal pressure required to induce urethral leakage. These values also were quite different, indicating that as far as the urethra is concerned abdominal pressure and detrusor pressure are not equivalent forces.

The cutaneo-urethral reflex. Description of the reflex and its role in stress urinary incontinence

The present communication describes the “cutaneo-urethral reflex” and its clinical significance. The study comprised 39 healthy volunteers and 14 patients with urinary stress incontinence. The periurethral skin was stimulated by pencil electrode and the EMG activity of the external urethral sphincter was recorded by concentric needle electrode inserted into the sphincter. The external urethral sphincter basal activity was increased with periurethral skin stimulation. The reflex response was absent when the external urethral sphincter or the periurethral skin were anesthetized. The recording of the cutaneo-urethral reflex in 14 urinary stress incontinent patients showed absence of reflex in 4 patients and weak activity in 10. These results suggest a weak external urethral sphincter in stress incontinence. Together with the absent or weak straining urethral reflex, it is believed that urinary stress incontinence is due to weak external urethral sphincter contraction on coughing; intra-urethral pressure, on coughing, is not elevated enough to be above the intravesical pressure, with a resulting urinary leak. EMG recording of the urethral reflex may thus prove valuable in the diagnosis of control urinary disorders and can be included as an investigative tool in such disorders.

The significance of prior anti-incontinence surgery in women who present with urinary incontinence

In a series of 148 consecutive female patients with urinary incontinence 62 (group 1) had undergone 1 or more prior anti-incontinence operations and 86 (group 2) had none. After clinical and urodynamic assessment the incidence of detrusor instability in the 2 groups (44 and 51 per cent) was not significantly different but the incidence of stress incontinence in group 1 was significantly greater than in group 2 (58 and 38 per cent, p less than 0.05). Of the 69 patients with a final diagnosis of stress urinary incontinence 45 (24 in group 1) had surgery and were followed for a mean of 17 months postoperatively. Of the patients 43 (95 per cent) were cured or improved. A total of 17 patients (71 per cent) in group 1 and 3 (17 per cent) in group 2 had a fascial sling. Eight patients had symptomatic postoperative detrusor instability and all had a fascial sling. There also was a significant decrease in postoperative peak flow rate (p less than 0.01) in these patients. Neither the number of previous operations nor the presence of preoperative detrusor instability had a significant effect on the incidence of postoperative detrusor instability.

Factors that influence the incidence of detrusor instability in women

Detrusor instability was examined in 108 women with urinary incontinence. The presence of instability correlated with the symptoms of urge incontinence in 81 of 99 patients. The technique of the cystometrogram also proved important and minor variations significantly altered the incidence. Finally, there seems to be a significant correlation between reduced urethral closure as measured by the urethral pressure profile and instability, suggestive of a causal relationship. An understanding of the factors that affect the incidence of detrusor instability will help to place it in the right perspective in terms of its diagnostic value and pathogenesis.

New dual-channel microtip transducer catheter for urethral pressure profile and cystometry

Urethral pressure profilometry performed with a dual-channel microtipped transducer catheter and its use in the clinical investigation of female urinary stress incontinence and bladder hyperreflexia are described. A technique for performing filling and voiding cystometry in conjunction with dual-channel profilometry also is discussed.

Spatial distribution and timing of transmitted and reflexly generated urethral pressures in healthy women

We localized the temporal and spatial distribution of pressures in the urethra to identify their contribution to continence. With the data obtained we resolved the timing between the passively transmitted and actively generated urethral pressures. Data were obtained from 11 healthy female volunteers, with a mean age of 22 years. Simultaneous measurements of bladder and urethral pressures were taken from subjects during the Valsalva maneuver and coughing, and then holding with the subject in the supine, standing and sitting positions. The ratio of urethral to bladder pressure increase and the latency between these pressure increases were analyzed. A biphasic pressure distribution results from coughing with subjects in all positions. The first phase occurs at the normalized distance of 10 to 15 per cent from the bladder neck, where the ratio of urethral to bladder pressure increase is 0.8. The second phase occurs at 60 to 70 per cent of the urethral length and has a 1.5 to 1.7 ratio of urethral to bladder pressure increase, indicating the presence of pressure magnification. Simultaneous latency measurements indicate that the pressure increase in the urethra precedes that of the bladder by 240 plus or minus 30 msec. in the region that exhibits maximum pressure magnification. These results indicate that a fast-acting contraction occurs in the distal third of the urethra, which contributes reflexly to the compressive forces of the proximal urethra, thereby preventing urine loss during stress.

Operative management of stress urinary incontinence

A total of 132 women with stress urinary incontinence underwent thorough radiographic and urodynamic evaluation in private urologic practice. With heavy reliance on the readily available technique of bead-chain cystography to differentiate between types I and II abnormalities, and to demonstrate the extent of bladder neck descent, the surgical success rates were 95.8 per cent over-all and 97.3 per cent using the Marshall-Marchetti-Krantz procedure. Postoperative complications were minimal and infrequent except for urinary retention in 31.7 per cent, which was managed easily by intermittent self-catheterization that allowed early hospital discharge without an indwelling catheter.

Correlation among cystometry, urethral pressure profilometry and pelvic floor electromyography in the evaluation of female patients with voiding dysfunction symptoms

We herein evaluate the correlation among cystometry, urethral pressure profilometry and pelvic floor electromyography in 137 female patients. The predominant symptom was frequency in 40 patients, urge incontinence in 31 and stress incontinence in 66. There appeared to be a correlation between urge incontinence and a hyperreflexic cystometrogram but no correlation was noted between either frequency or stress incontinence and the cystometrogram profile. The urethral pressure profile showed a correlation between stress incontinence and the lowest profile measurements. Frequency and urge incontinence had similar profile measurements except for maximum urethral planimetry. Electromyography showed that the external urethral sphincter had a different finding than the levator ani or the external anal sphincters in all 3 groups of female patients. The external urethral sphincter had a higher percentage of denervation than the other 2 muscles, especially in the stress incontinence group.

A simplified surgical technique for the therapy of stress incontinence

After a review of the literature on stress incontinence the importance of selecting the appropriate surgical procedure is emphasized. The long-term results of a modified and simplified method of retropubic urethropexy which has been used by the authors for 5 years are presented. The technique has been found equal in efficiency to other, more complicated, surgical methods.

Urethral pressure profile using microtip catheter in females

The use of urethral pressure profilometry in the clinical investigation of dysfunction of the female lower urinary tract is discussed. Included is a description of the use of two-channel microtip profilometry in the urethral syndrome, urinary retention, detrusor hyperreflexia, stress incontinence, and normal females. Dual-channel profilometry improves the diagnostic accuracy of urethral profile studies and aids in the understanding of lower urinary tract pathophysiology.