Urethral pressure reflectometry vs urethral pressure profilometry in women: a comparative study of reproducibility and accuracy

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.

Current and future perspectives on the utility of provocative tests of anal sphincter function: A state-of-the-art summary

BACKGROUND

The maintenance of fecal continence depends upon coordinated interactions between the pelvic floor, anorectum, and anal sphincter complex orchestrated by central and peripheral neural activities. The current techniques to objectively measure anorectal function rely on fixed diameter catheters placed inside the anal canal with a rectal balloon to obtain measurements of anal resting and squeeze function, and rectal compliance. Until recently it had not been possible to measure the distensibility of the anal canal, or in other words its ability to resist opening against an increasing pressure, which has been proposed as the main determinant of a biological sphincter's function. Anal acoustic reflectometry (AAR) and the functional lumen imaging probe (FLIP) are two novel, provocative techniques that dynamically assess the anal sphincter complex under volume-controlled distension. In doing so, both provide information on the viscoelastic properties of the anal canal and offer new insights into its function.

PURPOSE

This review details the current and potential future applications of AAR and FLIP and highlights the unanswered questions relevant to these new technologies.

Effect of a 5-HT2c receptor agonist on urethral closure mechanism in healthy women

AIMS

To evaluate the effect of ASP2205, a selective serotonin 5-HT_2c receptor agonist, and Duloxetine on the urethral pressure in healthy female subjects.

METHODS

Healthy females aged 18 to 55 years were recruited for this phase 1, single site, placebo-controlled, randomized, four-period, cross-over study. The interventions were single oral doses of 10 and 60 mg ASP2205, 80 mg duloxetine, and placebo. As a pharmacodynamics endpoint, opening urethral pressure (OUP), corrected for placebo, was measured using urethral pressure reflectometry under both resting and squeezing condition of the pelvic floor at predose and 3, 6, 12, and 24 hours after dosing. Safety and tolerability of ASP2205 were also compared with duloxetine and placebo.

RESULTS

Eighteen healthy women signed informed consent, however, one dropped out before dosing and one dropped out after the first period, therefore, 16 subjects completed the study. Duloxetine significantly increased the OUP during both resting and squeezing condition (maximal increase 18.1 and 16.8 cmH₂ O, respectively). Both doses of ASP2205 did not increase OUP at any time point. During squeezing OUP decreased significantly in the ASP2205 60 mg group from 6 to 24 hours after dosing. All subjects experienced predominantly central nervous system-related side effects (eg, dizziness and nausea) during ASP2205 treatment, which was most pronounced at 60 mg.

CONCLUSIONS

ASP2205, a serotonin 5-HT_2c receptor agonist, does not increase the urethral pressure and it is therefore unlikely that 5-HT _2c receptor agonists can be used as a treatment for stress urinary incontinence. ASP2205 was less well tolerated than the high dose of duloxetine.

The urethral closure mechanism is deteriorated after anterior colporrhaphy

INTRODUCTION AND HYPOTHESIS

Urethral pressure reflectometry (UPR) has proven highly reproducible in women with pelvic organ prolapse. We hypothesized that urethral parameters would decrease after anterior colporrhaphy.

METHODS

A prospective, observational study where women with anterior vaginal wall prolapse ≥stage II were assessed before and after anterior colporrhaphy. Assessments consisted of prolapse staging according to the Pelvic Organ Prolapse Quantification system, UPR measurements at rest, during squeezing and straining (at a standardized abdominal pressure of 50 cmH₂O, P_{O-Abd 50}), standardized stress tests with 300 ml saline, and answering the International Consultation on Incontinence - Urinary incontinence short form. Stress urinary incontinence (SUI) was defined as a positive stress test and a questionnaire with symptoms of SUI and a bother score > 1. Sample size was 30, power was 100% and the level of significance was 5%. We analyzed data with paired t-tests or non-parametric Wilcoxon signed rank tests; p-values <0.05 were considered statistically significant.

RESULTS

Twenty-eight women who underwent anterior colporrhaphy completed the study. P_{O-Abd 50} decreased 12 cmH₂O after surgery (p < 0.0001). Five women developed postoperative SUI and one had persistent SUI; the six women's preoperative P_{O-Abd 50} was lower than the rest (p < 0.01). If preoperative P_{O-Abd 50} was ≤65 cmH₂O, the positive predictive value for postoperative SUI was 50%, and if P_{O-Abd 50} was ≥85 cmH₂O, the negative predictive value was 100%.

CONCLUSIONS

The urethral closure mechanism deteriorates after anterior colporrhaphy. Using UPR, we can calculate a woman's risk of SUI after anterior colporrhaphy.

Posterior colporrhaphy does not affect the urethral closure mechanism

INTRODUCTION AND HYPOTHESIS

Studies have suggested that a posterior vaginal wall prolapse might compress the urethra and mask stress urinary incontinence (SUI), much like an anterior vaginal wall prolapse. A recent study with urethral pressure reflectometry (UPR) has shown that the urethral closure mechanism deteriorates after anterior colporrhaphy; this could explain the occurrence of postoperative de novo SUI. We hypothesized that urethral pressure would also decrease after posterior colporrhaphy.

METHODS

This was a prospective, observational study where women with posterior vaginal wall prolapse ≥stage II were examined before and after posterior colporrhaphy. We performed prolapse staging according to the Pelvic Organ Prolapse Quantification system, UPR measurements at rest, during squeezing and straining, and standardized stress tests with 300 ml saline. The women filled out International Consultation on Incontinence-Urinary incontinence (ICIQ-UI) short forms. The sample size was 18, with a power of 99.9% and a level of significance of 5%. Parameters were compared using paired t tests or Fisher's exact test, where appropriate; p values <0.05 were considered statistically significant.

RESULTS

Eighteen women with posterior vaginal wall prolapse ≥stage II were recruited. One woman did not undergo surgery. There were no changes in urethral pressure at rest (p = 0.4), during squeezing (p = 0.2) or straining (p = 0.2), before and after surgery. The results of the stress tests and ICIQ-UI short forms were the same after surgery.

CONCLUSIONS

The urethral closure mechanism is not affected by posterior colporrhaphy. Our study does not support the theory that the posterior vaginal wall prolapse compresses the urethra and masks SUI.

Urethral pressure reflectometry in women with pelvic organ prolapse: a study of reproducibility

INTRODUCTION AND HYPOTHESIS

The mechanism of continence in women with pelvic organ prolapse (POP) before and after surgery remains unknown. Urethral pressure reflectometry (UPR) separates women with stress urinary incontinence (SUI) from continent women by measuring urethral opening pressure at an abdominal pressure of 50 cmH₂O (P _{O-Abd 50}). UPR can help identify women with POP at risk of postoperative de novo SUI. The aim of this study was to investigate the reproducibility of UPR in women with POP.

METHODS

Women with anterior or posterior vaginal wall prolapse were recruited for this prospective, observational study from our outpatient clinic. The women were examined with UPR on two occasions. Measurements were done at rest, and during squeezing and straining. Statistical analyses were performed using SAS 9.4. A Bland-Altman analysis with limits of agreement and coefficients of variation was used to determine the level of agreement between measurements. Paired t tests were used to estimate the difference; a two-tailed P value of <0.05 was considered significant.

RESULTS

We recruited 19 women with anterior vaginal wall prolapse and 11 women with posterior vaginal wall prolapse. There were no significant differences in the opening pressures at rest or during squeezing or in the values of P _{O-Abd 50}. P _{O-Abd 50} showed limits of agreement of 15.3 cmH₂O and a coefficient of variation of 9.9 %.

CONCLUSIONS

UPR was found to be a highly reproducible method in women with POP. UPR may be used in future studies to help reveal urodynamic features predictive of postoperative de novo SUI in women with POP.

Evaluation and Classification of Stress Urinary Incontinence: Current Concepts and Future Directions

CONTEXT

Stress urinary incontinence (SUI) is a common and bothersome problem that frequently requires operative management. Over the past two decades, novel techniques have been introduced into clinical practice. With the greater variety of surgical options now available, there is an increasing focus on selecting the appropriate procedure for the individual patient based on the likely underlying pathophysiologic mechanism.

OBJECTIVE

To review the methods used in the evaluation of SUI and the proposed classification systems.

EVIDENCE ACQUISITION

A search of the PubMed database for the relevant search terms was conducted, and selected articles were retrieved and reviewed.

EVIDENCE SYNTHESIS

Standardised terminology for the description of SUI has been produced by the International Continence Society describing the problem in terms of symptoms, clinical signs, and urodynamic observations. The two major pathophysiologic theories that have emerged over the past 50 yr, urethral hypermobility and intrinsic sphincteric deficiency, have influenced the development and adoption of surgical techniques. It is now recognised that these two entities are not dichotomous but often coexist. The primary aim of the evaluation of the patient presenting with SUI is to confirm the diagnosis and assess symptom severity before instituting conservative treatments. Secondary evaluation consists of more sophisticated techniques that assess anatomy of the bladder neck and urethra under rest and stress (eg, videourodynamics, ultrasound) or direct or indirect physiologic measures of the integrity of the sphincter mechanism.

CONCLUSIONS

Classification of patients with SUI into distinct groups based on probable pathophysiologic mechanism could help guide the choice of surgical procedure, but current systems are likely too simplistic, and methods of assessment lack standardisation in techniques and sensitivity.

PATIENT SUMMARY

Urinary leakage on exertion, termed stress incontinence, is a common problem that affects many women. There is a need to develop better ways of categorising the underlying causes of leakage to ensure that patients receive the optimal treatments.

The impact of tension-free vaginal tape on the urethral closure function: mechanism of action

AIM

To investigate if the tension-free vaginal tape (TVT) works by increasing the abdominal to urethral pressure impact ratio (APIR).

METHODS

Twenty one women with urodynamically proven stress urinary incontinence (SUI) were assessed by ICIQ-SF, pad-weighing test, incontinence diary and Urethral Pressure Reflectometry (UPR) before and after TVT. UPR was conducted during resting and increased intra-abdominal pressure (P(Abd)) by straining. Related values of P(Abd) and urethral opening pressure (P(o)) were plotted into an abdomino-urethral pressuregram. Linear regression of the values was conducted, and the slope of the line was found. The slope expresses the ratio of pressure increase in the urethra compared to the pressure increase in the abdomen and was called APIR.

RESULTS

The urethral opening pressure at rest (P(o-rest)) was unchanged after TVT, while APIR increased in all women (from 0.7 to 1.4, P < 0.0001).

CONCLUSIONS

The TVT seems to strengthen the urethral closure function by increasing the APIR while P(o-rest) is unchanged regardless of the type of pre-operative dysfunction. This confirms the theory of TVT's mechanism of action being mid-urethral support.

Urethral pressure reflectometry, a novel technique for simultaneous recording of pressure and cross-sectional area in the prostatic urethra: testing in men without bothersome lower urinary tract symptoms

OBJECTIVE

Urethral pressure reflectometry (UPR) was introduced in 2005, for simultaneous measurement of pressure and cross-sectional area in the female urethra. It has shown to be more reproducible than conventional pressure measurement. Recently, it has been tested in the anal canal and the prostatic urethra. The primary aim of this study was to describe UPR in men without bothersome lower urinary tract symptoms.

MATERIAL AND METHODS

The study investigated 18 men, median age 59 (range 50-77) with UPR and pressure-flow analyses (PQ), the International Prostate Symptom Score and the Danish version of Prostate Symptom Score, flow rate, residual urine measurements, transrectal ultrasound, urethral pressure profilometry and visual analogue scale (Discomfort). UPR parameters measured were opening and closing pressure, opening and closing elastance and hysteresis, from the bladder neck to the sphincter region.

RESULTS

All UPR parameters increased significantly from the bladder neck to the sphincter region, except for the opening pressure between the prostate and the sphincter region. Seven men were obstructed according to PQ, but with no significant differences in any other standard urodynamic parameters. The hysteresis in the sphincter region was significantly lower in the obstructed group (p = 0.005). Discomfort was significantly lower with PQ compared to UPR (p = 0.04). Nine men had slight bleeding from the urethra during measurement with UPR.

CONCLUSIONS

The increase in all parameters from the bladder neck to the sphincter region is consistent with previous studies measuring the same parameters. The hysteresis may explain why seven men were obstructed according to PQ.

A faster urethral pressure reflectometry technique for evaluating the squeezing function

OBJECTIVE

Urethral pressure reflectometry (UPR) has shown to be superior in evaluating the squeeze function compared to urethral pressure profilometry. The conventional UPR measurement (step method) required up to 15 squeezes to provide one measure of the squeezing opening pressure and one measure of the squeezing elastance. The UPR technique was modified (so the examination last 7 s), requiring only one squeeze for the measurement to be made (continuous method). The aims of the study were to compare the UPR parameters measured during squeezing by the continuous method with measurements made by the step method and to measure the reproducibility of the continuous method.

MATERIAL AND METHODS

In total, 33 women were included (eight healthy and 25 with urodynamically proven stress urinary incontinence). The women were measured twice with the step method followed by five measurements with the continuous method.

RESULTS

No significant difference was seen between the mean squeezing opening pressures measured with the two methods. The squeezing elastance was significantly higher (p < 0.00001) with the continuous method (2.7 cmH₂O/mm²) than with the step method (1.9 cmH₂O/mm²). The coefficient of variation (CV) was 6.5% for the opening pressure measured with the continuous method and 14.8% for the squeezing elastance.

CONCLUSIONS

A new method for performing UPR measurements during squeezing has been described. With the new method a UPR measurement can be conducted during only one squeeze. The squeezing opening pressure is the same while the squeezing elastance is higher with the new method compared with the conventional method.

Urethral pressure reflectometry; a novel technique for simultaneous recording of pressure and cross-sectional area: a study of feasibility in the prostatic urethra

What's known on the subject? and What does the study add? In the 1980s and 1990s, a method for direct measurement of pressure and cross-sectional area in women and men was developed. It was successful in terms of obtaining meaningful results in several studies. But the technique, which was based on the field gradient principle, was never implemented in the clinical setting because of technical limitations. In 2005, urethral pressure reflectometry was introduced as a new technique in female urodynamics. The technique has been shown to be more reproducible than conventional urethral pressure profilometry, when measuring incontinence in women. In 2010 it was also introduced as a new measuring technique in the anal canal. This study, adds a new and interesting technique to the field of male urodynamics. For the first time, sound waves have been used to measure pressure and cross-sectional area simultaneously, directly in the prostatic urethra. The results from this first trial with urethral pressure reflectometry are promising, in terms of obtaining meaningful physiological parameters. Our hope is that, future trials will help us to be able to identify specific areas of obstruction or rigidity in the prostatic urethra, making treatment more direct and side effects from surgery less severe. However, further studies are needed to evaluate the technique with regards to clinical usefulness in men with benign prostatic obstruction.

OBJECTIVE

Urethral Pressure Reflectometry (UPR) was introduced in 2005, and it has since been used in the female urethra for simultaneous measurement of pressure (P) and cross-sectional area (CA). It has shown to be more reproducible than conventional pressure measurement and reintroduced direct measurement of pressure and elastance in the urethra as important parameters when assessing incontinent women. To test the feasibility of UPR in the prostatic urethra.

PATIENTS AND METHODS

We tested the technique in ten male patients, median age 73 and range 51-91. Measurements were performed in the supine position, with less than 50 ml of urine in the bladder. The UPR valuables measured were opening and closing pressure, opening and closing elastance and hysteresis.

RESULTS

The PVC tube was easy to insert to the same degree as a normal KAD. Opening pressure and opening elastance were measured on all patients. The sphincter area was easily identified during measurements. UPR provides results compatible with previous techniques. A standardized method for measurements was developed.

CONCLUSION

UPR has been shown feasible in the prostatic urethra. Further studies on healthy volunteers and patients with lower urinary tract symptoms and benign prostatic obstruction (BPO) are needed, to determine if UPR has a future role in urodynamic diagnostics of male patients with BPO.

Viscoelastic assessment of anal canal function using acoustic reflectometry: a clinically useful technique

BACKGROUND

Anal acoustic reflectometry is a new reproducible technique that allows a viscoelastic assessment of anal canal function. Five new variables reflecting anal canal function are measured: the opening and closing pressure, opening and closing elastance, and hysteresis.

OBJECTIVE

The aim of this study was to assess whether the parameters measured in anal acoustic reflectometry are clinically valid between continent and fecally incontinent subjects.

DESIGN

This was an age- and sex-matched study of continent and incontinent women.

SETTING

The study was conducted at a university teaching hospital.

PATIENTS

One hundred women (50 with fecal incontinence and 50 with normal bowel control) were included in the study. Subjects were age matched to within 5 years.

MAIN OUTCOME MEASURES

Parameters measured with anal acoustic reflectometry and manometry were compared between incontinent and continent groups using a paired t test. Diagnostic accuracy was assessed by the use of receiver operator characteristic curves.

RESULTS

Four of the 5 anal acoustic reflectometry parameters at rest were significantly different between continent and incontinent women (eg, opening pressure in fecally incontinent subjects was 31.6 vs 51.5 cm H2O in continent subjects, p = 0.0001). Both anal acoustic reflectometry parameters of squeeze opening pressure and squeeze opening elastance were significantly reduced in the incontinent women compared with continent women (50 vs 99.1 cm H2O, p = 0.0001 and 1.48 vs 1.83 cm H2O/mm, p = 0.012). In terms of diagnostic accuracy, opening pressure at rest measured by reflectometry was significantly superior in discriminating between continent and incontinent women in comparison with resting pressure measured with manometry (p = 0.009).

CONCLUSIONS

Anal acoustic reflectometry is a new, clinically valid technique in the assessment of continent and incontinent subjects. This technique, which assesses the response of the anal canal to distension and relaxation, provides a detailed viscoelastic assessment of anal canal function. This technique may not only aid the investigation of fecally incontinent subjects, but it may also improve our understanding of anal canal physiology during both the process of defecation and maintenance of continence.

How does the urothelium affect bladder function in health and disease? ICI-RS 2011

The urothelium is a multifunctional tissue that not only acts as a barrier between the vesical contents of the lower urinary tract and the underlying tissues but also acts as a sensory organ by transducing physical and chemical stresses to the attendant afferent nervous system and underlying smooth muscle. This review will consider the nature of the stresses that the urothelium can transduce; the transmitters that mediate the transduction process; and how lower urinary pathologies, including overactive bladder syndrome, painful bladder syndrome and bacterial infections, are associated with alterations to this sensory system. In particular, the role of muscarinic receptors and the TRPV channels system will be discussed in this context. The urothelium also influences the contractile state of detrusor smooth muscle, both through modifying its contractility and the extent of spontaneous activity; potential pathways are discussed. The potential role that the urothelium may play in bladder underactivity is introduced, as well as potential biomarkers for the condition that may cross the urothelium to the urine. Finally, consideration is given to vesical administration of therapeutic agents that influence urinary tract function and how the properties of the urothelium may determine the effectiveness of this mode of delivery.

Anal acoustic reflectometry: a new reproducible technique providing physiological assessment of anal sphincter function

BACKGROUND

Anal acoustic reflectometry is a new technique of assessing anal sphincter function. Five new variables reflecting anal canal function are measured: the opening and closing pressure, the opening and closing elastance, and hysteresis.

OBJECTIVE

This study aimed to compare the reproducibility of this new technique, in terms of test-retest and interrater reliability, with manometry, the current standard test of sphincter function.

DESIGN

This is a comparative study of reproducibility between anal acoustic reflectometry and manometry.

SETTINGS

This study was conducted at a university hospital (outpatient clinic and endoscopy unit).

PATIENTS

Twenty-six (21 female) subjects were assessed with both anal acoustic reflectometry and manometry on 2 separate occasions (test-retest reliability) and 22 (16 female) subjects were assessed with both methods by 2 separate investigators (interrater reliability).

MAIN OUTCOME MEASURES

Reproducibility was assessed according to the Bland-Altman method.

RESULTS

All of the measured novel anal acoustic reflectometry parameters had acceptable mean differences and repeatability coefficients. Comparison of the 2 methods of sphincter assessment (anal acoustic reflectometry vs manometry) was made for measurements taken at rest and during voluntary contraction. There was no significant difference in terms of test-retest reliability between the manometry maximum resting pressure vs the reflectometry opening pressure (P = .57) or manometry maximum squeeze pressure vs the reflectometry squeeze opening pressure (P = .68). No significant difference between methods was found in interrater reliability during assessments at rest (P = .62) and voluntary contraction (P = .96).

LIMITATIONS

Anal acoustic reflectometry is limited, as with all tests of anorectal function, in that the device is placed within the anal canal, causing stimulation of sensory and stretch receptors.

CONCLUSIONS

Anal acoustic reflectometry has a reproducibility comparable to manometry in terms of both test-retest and interrater reliability. Anal acoustic reflectometry is a promising technique that allows an assessment of anal canal physiology that is not available with manometry.

Anal acoustic reflectometry: a new technique for assessing anal sphincter function

OBJECTIVE

Anal acoustic reflectometry (AAR) is a new technique that offers an assessment of anal sphincter function by the measurement of additional parameters not available with conventional manometry. The aim of this study is to describe the technique, methodology and initial pilot study results.

METHOD

Wideband sounds (100 Hz to 16 kHz) are transmitted into a thin polyurethane bag placed within the anal canal. Calculation of cross-sectional area from reflected sound waves, over a range of pressures (0-200 cm H(2)O) during inflation/deflation of the bag, results in five physiological parameters of anal canal function. Five patients [three continent (two female) and two incontinent (both female)] were assessed with AAR and anal manometry.

RESULTS

Anal acoustic reflectometry parameters were reduced in incontinent when compared with continent patients. Resting Opening Pressures (cmH(2)O) were 27 and 16 in patients with faecal incontinence (FI) vs 44 and 72 in continent patients; Resting Opening Elastance (cmH(2)O/mm(2)) was 0.88 and 1.08 in FI patients vs 1.65 and 1.34 in continent patients. The Resting Opening Pressure of a similarly aged continent male (55 cmH(2)O) was greater than three of the females. During assessment of voluntary contraction (one FI female vs one continent female), Squeeze Opening Pressure (cmH(2)O) was 31 vs 100 and Elastance (cmH(2)O/mm(2)) 0.61 vs 2.07.

CONCLUSION

Anal acoustic reflectometry appears to be promising technique. Further work is in place to clarify whether it will be useful in clinical assessment of incontinent patients.

Urethral sleeve sensor: a non-withdrawal method to measure maximum urethral pressure

INTRODUCTION AND HYPOTHESIS

This study seeks to evaluate axial variation, comparisons with current technology, performance during dynamic conditions, and patient tolerability of the urethral sleeve sensor (USS) for maximal urethral closure pressure (MUCP) measurements.

METHODS

Eighteen continent and seven stress incontinent women underwent assessments with USS and urethral pressure profilometry (UPP) in random order. Intravesical (p (ves)) and urethral (p (ura)) pressure signals were collected and urethral closure pressure (p (clo)) was calculated. A visual analog scale (VAS) was used to evaluate subject discomfort.

RESULTS

The correlation coefficient between MUCP obtained by UPP and USS techniques was 0.86 (p < 0.001). Higher USS pressures were obtained with catheter oriented to 12 o'clock. Continent subjects demonstrated higher values of p (clo). MUCP became <0 cm H(2)O in subjects with clinical leakage during Valsalva, but not in continent subjects. Subjects tolerated the USS technique better than the UPP technique on VAS (p < 0.001).

CONCLUSIONS

USS technology can be used to evaluate the urethra in both static and dynamic conditions and is better tolerated than withdrawal techniques.

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.

Measurement of urethral closure function in women with stress urinary incontinence

PURPOSE

We assessed the use of urethral pressure reflectometry in detecting pressure increases in the female urethra and compared the usefulness of urethral pressure reflectometry vs urethral pressure profilometry in a pharmacodynamic intervention study.

MATERIALS AND METHODS

In this randomized, double-blind, placebo controlled, crossover study 17 women with stress urinary incontinence or mixed urinary incontinence received 4 mg esreboxetine or placebo for 7 to 9 days followed by a washout period before crossing over treatments. Urethral pressure reflectometry and urethral pressure profilometry were performed before and at the end of each treatment period.

RESULTS

The urethral opening pressure measured with urethral pressure reflectometry increased significantly compared to placebo by 13.7 cm H(2)O (p <0.0001) with an observed within subject standard deviation of 5.4. The increase in maximum urethral closure pressure was 8.4 cm H(2)O compared to placebo (p = 0.06) and for maximum urethral pressure the increase was 9.9 cm H(2)O (p = 0.04). However, the within subject SD for these parameters was higher at 11.4 and 12.2, respectively, implying lower power for these analyses. While receiving esreboxetine patients had significantly fewer incontinence episodes and reported a treatment benefit (global impression of change) compared to placebo.

CONCLUSIONS

The opening pressure measured with urethral pressure reflectometry was less variable compared to the parameters measured with urethral pressure profilometry (maximum urethral closure pressure and maximum urethral pressure). Consequently using urethral pressure reflectometry would result in a more efficient study design when investigating pharmacological effects on the urethra in future studies. We also found that esreboxetine was well tolerated, and had a positive and clinically relevant effect on urethral closure function and symptoms of stress urinary incontinence.

Urethral injection therapy: what is the mechanism of action?

AIMS

The mechanism of action of injection therapy is virtually unknown. Urethral Pressure Reflectometry (UPR) is a novel technique for measuring pressure and cross-sectional area in the urethra. UPR which provides reliable physiological meaningful parameters was used to study the mechanism of urethral injection therapy.

MATERIALS AND METHODS

Fifteen patients with stress urinary incontinence (nine women) and mixed incontinence (six women) were investigated with UPR before and 101 days after urethral injection therapy. The patients subjectively judged if their stress and urge symptoms were cured/improved almost unchanged or worsened.

RESULTS

Ten women were cured/improved after the injection therapy. None became worse. Six patients had urge symptoms before injection therapy which did not change after the procedure. The patients were divided into two groups based on their subjective assessments of effect. One group with effect (10 women) and 1 group without effect (5 women). The patients had significantly higher squeezing opening pressure after the treatment. The other parameters were unchanged. The mean squeezing opening pressure increased significantly (P < 0.01) more in the group of patients with effect (10.6 cmH(2)O) than in the group without effect (-1.6 cmH(2)O).

CONCLUSION

Injection therapy may work by increasing the power of the urethral sphincter. The bulking material may function as additional central filler volume which increase the length of the muscle fiber and thereby the power of the sphincter.