Inter-observer agreement in the estimation of bladder pressure using a penile cuff

Comparison of Penile Cuff Test and Conventional Urodynamic Study Prior to Photoselective Vaporization of Prostate for Benign Prostate Hyperplasia Using a 120 W GreenLight High Performance System Laser

Background: We compared the utility of the penile cuff test (PCT) and the conventional urodynamic study (UDS) for the preoperative assessment of patients undergoing scheduled photoselective vaporization of the prostate (PVP) for benign prostate hyperplasia (BPH). Methods: Fifty-nine patients with voiding lower urinary tract symptoms (LUTS) underwent a simultaneous PCT and conventional UDS before PVP. The modified International Continence Society (ICS) nomogram was used to confirm bladder outlet obstruction after measuring maximum urinary flow rate and highest pressure at flow interruption. The PCT and UDS results, in terms of modified ICS nomogram predictions, were compared. Their sensitivities, specificities, and positive and negative predictive values were calculated. Results: Thirty-six patients were diagnosed as obstructed and 23 as non-obstructed/equivocal using the modified ICS nomogram during the PCT. All 36 of the first group were confirmed as obstructed by UDS. Of the 23 diagnosed as non-obstructed/equivocal by the PCT, 14 were confirmed to be non-obstructed by UDS, with nine diagnosed as obstructed. The PCT showed a sensitivity of 80% and a specificity of 100%. The positive and negative predictive values were 100% and 60.9%, respectively. Conclusions: In conclusion, despite our small number of patients, the PCT’s high sensitivity and specificity suggest that it may provide diagnostic information about bladder outlet obstruction before PVP for patients with voiding LUTS. Evidently, the PCT has the potential to be used for some patients as a screening alternative to invasive UDS.

[How to evaluate BPH-related SBAUs in clinical practice and research?]

OBJECTIVE

To describe the useful explorations in the clinical evaluation of the symptoms of the lower urinary tract symptoms possibly related to BPH (LUTS/BPH), and to list the information necessary to allow an evaluation of an instrumental or surgical intervention in the treatment of the hypertrophy and benign prostatic obstruction.

METHOD

Bibliographic research in English using the European, American and French recommendations on the evaluation of BPH, supplemented by a Pubmed search.

RESULTS AND CONCLUSIONS

A number of systematic investigations into the evaluation of a man with LUTS/BPH include interrogation, clinical examination with rectal examination, urinalysis, flowmeter and post-micturition residual volume. The voiding catalog is necessary to understand the mechanism of a nocturia. PSA has a triple potential of interest: evaluation of the risk of progression, evaluation of the prostatic volume and diagnosis of a cancer of the prostate. Creatinine is needed only when chronic retention is observed and before surgery. Urethrocystoscopy is essential in case of hematuria, suspicion of stenosis of the urethra or bladder tumor. Ultrasound for evaluation of prostate volume is essential before surgery, and may be helpful in guiding the decision to prescribe a 5 alpha reductase inhibitor. No non-invasive technique has proven its possible substitution for pressure flow studies when indicated. When a researcher is considering evaluating a surgical or instrumental treatment for BPH, preoperative, perioperative and follow-up parameters are expected from readers to get a fair idea of the technique being evaluated. LEVEL OF EVIDENCE 5: Consensus d'experts.

Male bladder outlet obstruction: Time to re-evaluate the definition and reconsider our diagnostic pathway? ICI-RS 2015

The diagnosis of bladder outlet obstruction (BOO) in the male is dependent on measurements of pressure and flow made during urodynamic studies. The procedure of urodynamics and the indices used to delineate BOO are well standardized largely as a result of the work of the International Continence Society. The clinical utility of the diagnosis of BOO is however, less well defined and there are several shortcomings and gaps in the currently available medical literature. Consequently the International Consultation on Incontinence Research Society (ICI-RS) held a think tank session in 2015 entitled "Male bladder outlet obstruction: Time to re-evaluate the definition and reconsider our diagnostic pathway?" This manuscript details the discussions that took place within that think tank setting out the pros and cons of the current definition of BOO and exploring alternative clinical tests (alone or in combination) which may be useful in the future investigation of male patients with lower urinary tract symptoms. The think tank panel concluded that pressure-flow studies remain the diagnostic gold-standard for BOO although there is still a lack of high quality evidence. Newer, less invasive, investigations have shown promise in terms of diagnostic accuracy for BOO but similar criticisms can be levelled against these tests. Therefore, the think tank suggests further research with regard to these alternative indicators to determine their clinical utility.

Correlation between penile cuff test and pressure-flow study in patients candidates for trans-urethral resection of prostate

Background

Aim of this study was to make a comparison between penile cuff test (PCT) and standard pressure-flow study (PFS) in the preoperative evaluation of patients candidates for trans-urethral resection of prostate (TURP) for benign prostatic obstruction (BPO).

Methods

We enrolled male patients with lower urinary tract symptoms candidates for TURP. Each of them underwent a PCT and a subsequent PFS. A statistical analysis was performed: sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), likelihood ratio and ratio of corrected classified were calculated. Fisher exact test was used to evaluate relationships between PCT and maximal urine flow (Q_max): a p-value < 0.05 was considered statistically significant.

Results

We enrolled 48 consecutive patients. Overall, at PCT 31 patients were diagnosed as obstructed and 17 patients as unobstructed. At the subsequent PFS, 21 out of 31 patients diagnosed as obstructed at PCT were confirmed to be obstructed; one was diagnosed as unobstructed; the remaining 9 patients appeared as equivocal. Concerning the 17 patients unobstructed at PCT, all of them were confirmed not to be obstructed at PFS, with 10 equivocal and 7 unobstructed. The rate of correctly classified patients at PCT was 79% (95%-CI 65%-90%). About detecting obstructed patients, PCT showed a SE of 100% and a SP of 63%. The PPV was 68%, while the NPV was 100%.

Conclusions

PCT can be an efficient tool in evaluating patients candidates for TURP. In particular, it showed good reliability in ruling out BPO because of its high NPV, with a high rate of correctly classified patients overall. Further studies on a huger number of patients are needed, including post-operative follow-up as well.

Application of guidelines to the evaluation of the male patient with urgency and/or incontinence

PURPOSE OF REVIEW

To review and evaluate the evidence from contemporary evidence-based guidelines regarding the assessment of men with urinary urgency and/or incontinence.

RECENT FINDINGS

There are a number of evidence-based guidelines which describe the pathways for assessing men with the symptoms of urgency and/or incontinence. We summarize the conclusions of the European Association of Urology, American Urological Association and National Institute of Clinical Excellence guidelines.

SUMMARY

All guidelines recommend a directed history, examination (including digital rectal examination), urinalysis and bladder diary as being essential in the assessment of men with lower urinary tract symptoms, although there are no high levels of evidence studies to support this. Creatinine estimation and prostate-specific antigen are recommended in selected groups of men, the latter after appropriate counselling. Uroflowmetry with postvoid residual assessment is recommended for at specialist assessment. Pad tests may be useful to quantify leakage. Ultrasound assessment of prostatic size and protrusion into the bladder base may be useful. Cystometry is recommended for men considering prostatic surgery, although there is a poor level of evidence underpinning this. Noninvasive surrogates for cystometry, such as penile plethysmography, lack sufficient evidence to allow recommendations to be made.

Longitudinal changes in isovolumetric bladder pressure in response to age-related prostate growth in 1,020 healthy male volunteers

AIM

To non-invasively study if compensation and decompensation occurs in the urinary bladder of healthy male volunteers in response to benign prostatic enlargement (BPE) using the condom catheter method.

METHODS

Between 2001 and 2010, 1,020 healthy male volunteers were included in a longitudinal study based on three non-invasive urodynamic examinations during a 5-year follow-up. Inclusion criteria were an informed consent, the ability to void in a normal standing position and a minimum free flow rate of 5.4 ml/sec. Study parameters were prostate volume (PV), maximum free urinary flow rate (Q(max)) and bladder contractility, quantified by the maximum isovolumetric bladder pressure, measured in the condom (P(cond.max)). Volunteers also completed the International Prostate Symptom Score Form (IPSS).

RESULTS

Within limitations, the included volunteers had a flat age distribution between 38 and 72 years. This made it possible to combine longitudinal analysis in a 5-year observation interval, with cross sectional analysis in a 35-year age range. Longitudinal analysis showed that with increasing age, PV increased with 1.9% per year, whereas Qmax decreased with 1.1% per year. IPSS increased with 1.1% per year when volunteers were older than 55 years. P(cond.max) increased during the 5-year longitudinal follow-up, but not in the cross sectional analysis.

CONCLUSIONS

The difference between cross sectional and longitudinal results of the P(cond.max) may have been caused by compensation of the urinary bladder resulting in a selection effect. This would imply that compensation is a relatively fast process, taking approximately 5 years.

The penile cuff test: A clinically useful non-invasive urodynamic investigation to diagnose men with lower urinary tract symptoms

Objectives:

To summarize the development of a novel non-invasive test to categorize voiding dysfunction in men complaining of lower urinary tract symptoms (LUTS) - the penile cuff test.

Methods:

The test involves the controlled inflation of a penile cuff during micturition to interrupt voiding and hence estimate isovolumetric bladder pressure (p_ves.isv). The validity, reliability, and clinical usefulness of the test were determined in a number of studies in men with LUTS.

Results:

The penile cuff test can be successfully performed in over 90% of men with LUTS. The reading of cuff pressure at flow interruption (p_cuff.int) gives a valid and reliable estimate of invasively-measured p_ves.isv and when combined with the reading for maximum flow rate obtained during the test (Q_max) produces an accurate categorization of bladder outlet obstruction (BOO). Use of this categorization prior to treatment allows improved prediction of outcome from prostatectomy.

Conclusion:

The penile cuff test fulfils the criteria as a useful clinical measurement technique applicable to the diagnosis and treatment planning of men with LUTS.

Interobserver agreement for noninvasive bladder pressure flow recording with penile cuff

PURPOSE

We assessed variability in interpreting noninvasive measurements of bladder pressure and urine flow between experienced and novice users of the penile cuff.

MATERIALS AND METHODS

Urodynamicists at 6 sites were asked to use the penile cuff test as part of clinical assessment in 30 men presenting with lower urinary tract symptoms. After a short training period they measured maximum flow rate and cuff interruption pressure from penile cuff test recordings to enable categorization of bladder outlet obstruction using a nomogram. Similar measurements were then made on the same traces by 2 expert observers from the originating center. Interobserver differences were assessed.

RESULTS

Complete agreement on obstruction categorization was seen in 77% of subjects, which increased to 86% when plots positioned on category boundary lines were allocated to the favored category. The 95% confidence limits of interobserver variability in maximum flow rate and cuff interruption pressure measurements were +/- 1.7 ml per second and +/- 13 cm H(2)O, respectively, although a small number of studies yielded discrepancies between observers that were larger than expected. They arose from complex recordings but were equally likely between experts as between expert and novice. Investigation of the causes suggested in some cases how such discrepancies may be avoided in the future.

CONCLUSIONS

The excellent level of agreement in measurement and categorization after a short training period suggests that introducing the penile cuff test as part of assessment in men with lower urinary tract symptoms would be straightforward.

Variation in invasive and noninvasive measurements of isovolumetric bladder pressure and categorization of obstruction according to bladder volume

PURPOSE

We developed a noninvasive test that provides an estimate of isovolumetric bladder pressure by measuring the pressure required to interrupt voiding using controlled inflation of a penile cuff. We noted variation in serial measurements obtained during a single void and, therefore, we determined whether this represents variation in detrusor contraction strength, as predicted in previous studies, or measurement error.

MATERIALS AND METHODS

A total of 36 symptomatic men underwent simultaneous invasive and noninvasive pressure flow studies. Corresponding values of isovolumetric bladder pressure and cuff interruption pressure were recorded at each flow interruption and grouped according to bladder volume to calculate measurement error and bias at various points during a void. Individual variation in the 2 measurements across a range of normalized bladder volumes was then examined using ANOVA.

RESULTS

Cuff interruption pressure showed a consistent level of accuracy as an estimate of isovolumetric bladder pressure across a range of volumes. There were similar, statistically significant differences in isovolumetric bladder pressure and cuff interruption pressure recorded at specific volume increments with the highest values seen in the mid range and the lowest seen at lower bladder volumes (each p <0.01). When plotting, the maximum recorded value of cuff interruption pressure in each individual on our proposed noninvasive pressure flow nomogram provided the best diagnostic accuracy for obstruction.

CONCLUSIONS

This study shows that cuff interruption pressure varies in the expected manner with bladder volume and provides a consistent estimate of isovolumetric bladder pressure throughout a void. These data provide important guidance for interpreting noninvasive pressure flow studies and classifying obstruction on the proposed nomogram.

Noninvasive methods of diagnosing bladder outlet obstruction in men. Part 2: Noninvasive urodynamics and combination of measures

PURPOSE

Many methods have been suggested to diagnose bladder outlet obstruction, as defined by the gold standard of pressure flow studies. Difficulty arises when comparing completely different methods of diagnosing bladder outlet obstruction. A comprehensive review of the literature on the different methods used to diagnose bladder outlet obstruction by noninvasive means was performed with a view to allow such a comparison.

MATERIALS AND METHODS

A MEDLINE search was done of the published literature covering until the end of 2004 on noninvasive methods, including single measure and combinations of measures, to diagnose bladder outlet obstruction. A direct comparison of all of the different methods was made using the sensitivity, specificity, likelihood ratio, and pretest and posttest probability of diagnosing bladder outlet obstruction for each test. For many techniques these values were calculated from the data presented in the article.

RESULTS

A multitude of methods has been applied to diagnose bladder outlet obstruction. Broadly the methods were divided into nonurodynamic and noninvasive urodynamic methods. Nonurodynamic methods were considered in part 1 of the review. Part 2 considered noninvasive urodynamic techniques, such as uroflowmetry, the penile cuff, the condom method and Doppler urodynamics. A combination of single measures was also considered and the relative merits of these approaches were discussed.

CONCLUSIONS

A combination of noninvasive urodynamics and ultrasound derived measures provide promising methods of diagnosing bladder outlet obstruction. However, pressure flow studies still remain the gold standard for assessing bladder outlet obstruction.

A NOMOGRAM TO CLASSIFY MEN WITH LOWER URINARY TRACT SYMPTOMS USING URINE FLOW AND NONINVASIVE MEASUREMENT OF BLADDER PRESSURE

PURPOSE

Bladder pressure during voiding can be estimated by a noninvasive technique using controlled inflation of a penile cuff. This test provides a valid and reliable estimate of isovolumetric bladder pressure but to our knowledge the role of the test for the routine clinical treatment of patients with lower urinary tract symptoms (LUTS) has yet to be demonstrated. As a first step, we evaluated a proposed nomogram for the diagnosis of bladder outlet obstruction in men with LUTS using noninvasive measurements of pressure and flow.

MATERIALS AND METHODS

Using a combination of theoretical calculation and experimental data the existing International Continence Society pressure flow nomogram was modified to allow noninvasive measurement of isovolumetric bladder pressure in place of detrusor pressure at maximum urine flow. Accuracy of the nomogram for classifying obstruction was then tested in a group of 144 men with LUTS who underwent an invasive and a noninvasive pressure flow study.

RESULTS

The modified nomogram identified men with obstruction with 68% positive predictive value and 78% negative predictive value. Predictive accuracy could be improved by adding an additional criterion of obstruction, that is maximum urine flow less than 10 ml second, whereby an identifiable 69% of all cases could be classified as obstructed (88% positive predictive value) or not obstructed (86% negative predictive value). In the remaining 31% of patients invasive pressure flow studies would provide additional information, although some results would remain equivocal.

CONCLUSIONS

The proposed nomogram combined with the additional flow rate criterion can classify more than two-thirds of cases without recourse to invasive pressure flow studies. We must now evaluate the usefulness of this classification for the treatment of men with LUTS.

NONINVASIVE ASSESSMENT OF BLADDER CONTRACTILITY IN MEN

PURPOSE

Preoperative assessment of detrusor function by pressure flow study (PFS) improves outcome from prostatectomy but is invasive and uncomfortable for the patient. We report on a large scale validation of a novel noninvasive assessment of detrusor contractility.

MATERIALS AND METHODS

A flexible cuff placed around the penis was inflated automatically during voiding until flow interruption. Cuff pressure at interruption (pcuff.int) reflects isovolumetric bladder pressure (pves.isv), a measure of detrusor contractility. For comparison 151 symptomatic men performed the cuff test with simultaneous PFS monitoring. Test/retest agreement was assessed in 91 subjects who performed a cuff test without PFS on 2 occasions.

RESULTS

For the 117 (77%) subjects with an acceptable cuff pressure flow trace, Bland Altman analysis showed that pcuff.int overestimated pves.isv by a mean (s.d.) of 16.4 (27.5) cm H2O, predominantly due to the cuff being positioned below the bladder. For test/retest analysis 52 (57%) of the men who were able to attend twice provided acceptable cuff data on both occasions with a mean (s.d.) difference in pcuff.int of -3.3 (32.0) cm H2O, improving to 0.0 (20.3) cm H2O in a subgroup of 39 subjects who voided more than 150 ml. On questionnaire assessment 121 (80%) subjects preferred the cuff test to PFS.

CONCLUSIONS

The cuff test gives a valid and reproducible estimate of isovolumetric bladder pressure in a manner acceptable to patients, although test failure and variability of agreement require improvement. The test may be of value in the assessment of urinary symptoms and may aid in patient selection for prostatectomy.

Noninvasive Techniques for the Measurement of Isovolumetric Bladder Pressure

PURPOSE

A total of 184,000 prostatectomies were performed in the United States in 2000 for the relief of presumed bladder outlet obstruction. However, it has been reported that prostatectomy using current indications fails to bring about symptomatic improvement in approximately one-fourth of patients. Pressure flow studies are currently recognized as the gold standard for the diagnosis of bladder outlet obstruction. However, these studies are associated with a number of disadvantages. They are time consuming, invasive and expensive, and carry some morbidity for the patient. It has been suggested that the use of pressure flow studies should be mandatory before surgery. The invasive nature of this test limits its application, and a variety of noninvasive methods have been suggested to circumvent the need for conventional urodynamics.

MATERIALS AND METHODS

We conducted a MEDLINE search of the published literature on the use of noninvasive techniques to measure bladder pressure.

RESULTS

Two promising techniques involve the noninvasive measurement of isovolumetric detrusor pressure. The first of these methods uses an external condom catheter and the second an inflatable cuff around the penis. Both of these methods rely on the interruption of urinary flow and the measurement of the bladder pressure transmitted along the fluid column between bladder and site of urethral occlusion. An alternative strategy analyzes flow patterns following compression and release of the urethra during voiding.

CONCLUSIONS

Of the methods reported the penile cuff, which is inflated during voiding, or the penile squeeze technique, which infers bladder pressure from flow patterns, would seem the most likely to be clinically useful. A noninvasive measure of bladder pressure, allied to a free flow rate, would give a useful adjunct to the assessment of men with lower urinary tract symptoms.