The UroCuff Test
The UroCuff Test is a non-invasive pressure-flow study for patients reporting lower urinary tract symptoms (LUTS) such as urgency, frequency, nocturia, and incomplete emptying, or who have noted other changes in voiding patterns. The UroCuff provides the urologist with necessary data for diagnosis of voiding disorders.
Key Benefits of The UroCuff:
The UroCuff Test is the new standard in non-invasive LUTS diagnostics. Moreover, the UroCuff offers your practice a LUTS patient management platform providing better clinical outcomes and greater efficiency. The UroCuff is simply a better way to manage LUTS patients in the today’s healthcare system.
How It Works
The UroCuff Test simultaneously measures urine flow rate and bladder pressure to assist in determining the underlying cause of the voiding disorder. Bladder pressure is measured non-invasively with a penile cuff (resembling a blood pressure cuff) instead of a catheter. The principle of the test is similar to blood pressure measurement. When the patient is ready to void, a small pneumatic cuff is fitted around the penis, and the patient is asked to void into the flow meter. When voiding has commenced, the cuff is inflated under automatic control until the stream is interrupted. Inflation cycles are repeated until the void is complete. The cuff pressure required to interrupt flow equals bladder pressure at the time of interruption.
Once the test is complete, the UroCuff report summarizes the pressure-flow data on a modified nomogram. Shown to the right are nomograms from two different patients that had identical maximum flow rates of 3.1 ml/s. These patients are therefore both “low flow rate” patients, and they would present with the same flow rates when the traditional uroflow test is prescribed. However, the UroCuff nomogram on the top reveals that the first patient has a low bladder pressure, while the nomogram on the bottom reveals the second patient has high bladder pressure. Click on either of these nomograms to see the complete UroCuff report.
Optionally, one or two surface EMG electrodes may be applied to the patient to monitor skeletal muscle function during the void:
a. Perineal EMG Placement–to monitor sphincter activity.
b. Abdominal EMG Placement–to monitor abdominal straining.
For a technical explanation of how the UroCuff Test works
Click here – “Principles of the UroCuff™ Test” (PDF)
The UroCuff Test has a simple and consistent touch-screen interface that guides the clinician step-by-step through each test. The hardware consists of the following components:
Peer Review Publications
The UroCuff Test is widely written about with positive attestation in peer-reviewed clinical literature. You may use The UroCuff Test Clinical Literature Summary as a single source for most of this literature. Alternatively, you may refer to the individual citations along with abstracts and links to the complete documents provided below.
To assure that patients with lower urinary tract symptoms (LUTS) benefit from interventions, urologists must practice careful selection of surgical candidates. Currently, 15%-30% of men do not benefit optimally from these invasive and potentially morbid procedures. Success rates following transurethral resection of the prostate (TURP) are higher if bladder outlet obstruction (BOO) is confirmed prior to the procedure by invasive pressure flow studies (PFS). However, PFS may not be performed because of many reasons. We report a study of a non-invasive method of assessing BOO.
Materials and Methods
The UroCuff test was compared to invasive urodynamic studies in adult males with lower urinary tract symptoms. Patients undergoing PFS for LUTS presumed to be due to BOO were recruited from a single site to perform a penile cuff test (UroCuff) at the same time as PFS. Standard PFS were performed followed immediately by a penile cuff test in the same test setting. The results were compared using basic statistical analysis.
A total of 19 men were evaluated by both PFS and UroCuff evaluation. Using PFS as the gold standard, the positive predictive value of the UroCuff penile cuff test to diagnose BOO was found to be 92%. The sensitivity of the UroCuff test for detecting BOO was 75%. When compared to PFS, patients preferred the UroCuff 100% of the time.
The UroCuff test is accurate in predicting BOO when compared to conventional invasive pressure flow studies in men with LUTS. It is well tolerated and preferred over invasive pressure flow studies.
To assess whether the penile cuff non-invasive urodynamic test serves as an effective diagnostic tool for predicting outcomes prior to disobstructive surgery for men presenting with voiding lower urinary tract symptoms. Patients with proven urodynamic obstruction do better after surgery. The current gold standard, invasive pressure-flow studies, imposes cost, resource demand, discomfort and inconvenience to patients.
Patients and Methods
Patients undergoing surgery for prostatic obstruction at Palmerston North Hospital had pre-operative non-invasive urodynamics and completed an International Prostate Symptom Score (IPSS). Catheterised patients were excluded. Two months post-operatively they completed a further IPSS score. An improvement of seven or greater was defined as a clinically successful outcome. Results were compared with the outcome predicted by the nomogram supplied with the urodynamic device.
Data was obtained for 62 patients with mean age 70 years (range 49 to 86 years; SD 9 years). Follow-up was complete for all patients. Thirty-eight patients underwent transurethral resection and 24 holmium laser enucleation of the prostate. Mean IPSS score was 21 (range 5 to 35; SD 6) pre-operatively and 11 (range 1 to 31; SD 9) post-operatively. Thirty-five patients were predicted obstructed and 27 not obstructed. 94% of those predicted obstructed had a successful outcome (p < 0.01). 70% predicted as not obstructed did not have a successful outcome after surgery (p < 0.01).
The penile cuff test is an exciting adjunct in the decision to proceed to surgery for prostatic obstruction. Patients predicted to be obstructed have an excellent likelihood of a good surgical outcome, yet 30% of those shown not to be obstructed will still do well. Whilst numbers in our study are small, outcomes compare favourably with published results on invasive urodynamic methods.
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).
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 (Qmax): a p-value < 0.05 was considered statistically significant.
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%.
The 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.
NHS Centre for Evidence-based Purchasing Verdict – Significant Potential:
The Mediplus CT3000 system offers greater accuracy in diagnosis of BOO than diagnosis based on flow rate measurement alone. Recent results (3) suggest its prediction of outcome from surgery rivals that offered by invasive urodynamic studies, though this has not been conclusively proven by this limited evidence. The invasive approach also provides additional information, and therefore remains the gold standard for the diagnosis of BOO in men. The existing evidence supports the manufacturer’s claim that the CT3000 system has a useful role as an adjunct to current methods. Diagnoses based on CT3000 and urine flow measurement can be compared. Where there is agreement, surgery is indicated, and where there is disagreement or uncertainty, follow up invasive urodynamics are indicated. This approach may well reduce the number of ineffective surgical prostatectomies while also reducing the number of invasive studies, both of which carry associated costs and risks. Independent validating studies on the Mediplus CT3000 cuff system are recommended, and a multi-centre trial is reported to be underway (3). A detailed economic evaluation is also recommended, considering both the costs and consequences of the diagnostic accuracy of the CT3000 system.
This article defines the need for objective measurements to help diagnose the cause of lower urinary tract symptoms (LUTS). It describes the conventional techniques available, mainly invasive, and then summarizes the emerging range of non-invasive measurement techniques.
Materials and Methods
This is a narrative review derived from the clinical and scientific knowledge of the authors together with consideration of selected literature. The CT3000 UroCuff test was compared to traditional catheter based urodynamic studies in adult males with lower urinary tract symptoms.
Consideration of measured bladder pressure urinary flow rate during voiding in an invasive pressure flow study is considered the gold standard for categorization of bladder outlet obstruction (BOO). The diagnosis is currently made by plotting the detrusor pressure at maximum flow (PdetQmax) and maximum flow rate (Qmax) on the nomogram approved by the International Continence Society. This plot will categorize the void as obstructed, equivocal or unobstructed. The invasive and relatively complex nature of this investigation has led to a number of inventive techniques to categorize BOO either by measuring bladder pressure non-invasively or by providing a proxy measure such as bladder weight.
Non-invasive methods of diagnosing BOO show great promise and a few have reached the stage of being commercially available. Further studies are however needed to validate the measurement technique and assess their worth in the assessment of men with LUTS.
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.
The test involves the controlled inflation of a penile cuff during micturition to interrupt voiding and hence estimate isovolumetric bladder pressure (pves.isv). The validity, reliability, and clinical usefulness of the test were determined in a number of studies in men with LUTS.
The penile cuff test can be successfully performed in over 90% of men with LUTS. The reading of cuff pressure at flow interruption (pcuff.int) gives a valid and reliable estimate of invasively-measured pves.isv and when combined with the reading for maximum flow rate obtained during the test (Qmax) produces an accurate categorization of bladder outlet obstruction (BOO). Use of this categorization prior to treatment allows improved prediction of outcome from prostatectomy.
The penile cuff test fulfils the criteria as a useful clinical measurement technique applicable to the diagnosis and treatment planning of men with LUTS.
We assessed variability in interpreting noninvasive measurements of bladder pressure and urine flow between experienced and novice users of the penile cuff.
Materials & 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.
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 H2O, 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.
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.
We performed a pragmatic study of the penile cuff test, a noninvasive method of categorizing bladder outlet obstruction, at a number of United Kingdom urology centers remote from the originating site. We report the agreement of the test and the subsequent retest using the cuff test in the short term.
Men requiring urodynamic investigation for lower urinary tract symptoms were recruited from 6 sites to perform a penile cuff test twice at an interval of approximately 4 weeks. Tests were analyzed by a single interpreter to assess differences in the flow rate, cuff interruption pressure and diagnostic categorization in an individual between the 2 tests due to measurement and physiological error.
A total of 136 men (69%) performed 2 suitable cuff tests at a median of 20 days (IQR 8–31). The mean ± SD difference between the 2 tests in the maximum flow rate was 0.2 ± 3.7 ml per second and in cuff interruption pressure was 4.0 ± 26 cm H2O. Of the men 33% changed diagnostic category on the Newcastle nomogram, while 47% maintained a consistent diagnosis of obstruction or no obstruction.
Diagnostic category repeatability was similar to that of conventional urodynamics, although there was greater variability in pressure measurements. This supports widespread routine use of the penile cuff test.
We determined whether categorizing men with lower urinary tract symptoms using a noninvasive pressure flow nomogram is sensitive to change following the removal of obstruction.
Materials and Methods
A prospective cohort of men undergoing transurethral prostate resection was recruited, of whom 143 (69%) underwent noninvasive pressure flow study using the penile cuff technique before and 4 months following surgery. Cuff pressure required to interrupt voiding, estimated isovolumetric bladder pressure and maximum flow rate were recorded during a single void. Values were plotted on a nomogram categorizing cases as obstructed (upper left quadrant), not obstructed (lower right quadrant) or diagnosis uncertain (upper right and lower left quadrants). Changes in maximum flow rate, cuff pressure required to interrupt voiding and nomogram position following transurethral prostate resection were then analyzed.
Transurethral prostate resection resulted in an improved flow rate for all diagnostic groups, which was highest for obstructed cases with a mean ± SD increase of 11 ± 6 ml second (p <0.01). Men categorized with obstruction and those placed in the upper right quadrant showed significant decreases in cuff pressure required to interrupt voiding following transurethral prostate resection with a mean decrease of – 45 ± 35 and – 48 ± 32 cm H2O, respectively (p <0.01). The number of cases classified as not obstructed increased from 28 (19%) preoperatively to 114 (80%) after transurethral prostate resection.
Sensitivity to change following the removal of obstruction further validated the usefulness of noninvasive measurement of bladder pressure by the penile cuff test and the categorization of obstruction by the noninvasive nomogram. Decreased isovolumetric bladder pressure following transurethral prostate resection may reflect a return to normal detrusor contraction strength.
To determine whether categorisation of bladder outlet obstruction (BOO) using measurements of bladder pressure and urine flow obtained by a novel noninvasive medical device (the penile cuff test) improves prediction of outcome from endoscopic prostatectomy (TURP).
A consecutive cohort of 208 men undergoing TURP following standard assessment in our institution was recruited, and 179 (86%) completed the protocol. Each subject underwent a penile cuff test prior to surgery; outcome was assessed by change in IPSS at 4 mo. The proportion of men with good outcome (>50% reduction in IPSS) was compared according to categorisation by noninvasive bladder pressure and urine flow measurements.
The cuff test was completed by 93% of men with 2% experiencing an adverse event. Men categorised as having BOO by the test (37% of total) had an 87% chance of a good outcome from TURP (p < 0.01), whilst of those deemed not obstructed (19% of total) 56% experienced good outcome (p < 0.01). For the remaining men not categorised in these two groups, 77% had good outcome, which was identical to the result of the cohort as a whole (77%, p = NS).
Urodynamic categorisation using measurements obtained by the noninvasive penile cuff test improves prediction of outcome for men with LUTS undergoing TURP. This finding together with the ease and acceptability of the test suggest its suitability for office-based clinical use to assist men and their physicians in the selection for surgical treatment for relief of LUTS.