Robert Pickard

NONINVASIVE MEASUREMENT OF BLADDER PRESSURE BY CONTROLLED INFLATION OF A PENILE CUFF

PURPOSE A noninvasive test providing reliable objective quantification of bladder pressure during the voiding cycle would make an important contribution to the management of lower urinary tract symptoms. We developed a new noninvasive test to measure bladder pressure in males based on controlled inflation of a penile cuff during voiding. We compared the new technique with simultaneous invasive bladder pressure measurement. MATERIALS AND METHODS We evaluated 7 volunteers and 32 patients. A conventional pressure flow study was performed first. The bladder was refilled, a penile cuff was fitted and after voiding commenced the cuff was inflated in steps of 10 cm. water every 0.75 seconds until urine flow was interrupted. The cuff was rapidly deflated, allowing flow to resume, and the cycle was repeated until the end of voiding. The flow rate was graphed against cuff pressure for each interruption cycle to determine the pressure at which flow was interrupted. This pressure was compared with simultaneous invasive isovolumetric bladder pressure. RESULTS Invasive and noninvasive pressure measurements agreed well. Average cuff pressure at interruption of flow exceeded mean simultaneous isovolumetric bladder pressure plus or minus standard deviation by 14.5 +/- 14.0 cm. water. CONCLUSIONS The new method provides noninvasive quantitative information on voiding bladder pressure in males. Further study is required to assess whether the technique can contribute to the management of lower urinary tract symptoms.

Update on biofilm infections in the urinary tract

PurposeBiofilm infections have a major role in implants or devices placed in the human body. As part of the endourological development, a great variety of foreign bodies have been designed, and with the increasing number of biomaterial devices used in urology, biofilm formation and device infection is an issue of growing importance.MethodsA literature search was performed in the Medline database regarding biofilm formation and the role of biofilms in urogenital infections using the following items in different combinations: “biofilm,” “urinary tract infection,” “bacteriuria,” “catheter,” “stent,” and “encrustation.” The studies were graded using the Oxford Centre for Evidence-based Medicine classification.ResultsThe authors present an update on the mechanism of biofilm formation in the urinary tract with special emphasis on the role of biofilms in lower and upper urinary tract infections, as well as on biofilm formation on foreign bodies, such as catheters, ureteral stents, stones, implants, and artificial urinary sphincters. The authors also summarize the different methods developed to prevent biofilm formation on urinary foreign bodies.ConclusionsSeveral different approaches are being investigated for preventing biofilm formation, and some promising results have been obtained. However, an ideal method has not been developed. Future researches have to aim at identifying effective mechanisms for controlling biofilm formation and to develop antimicrobial agents effective against bacteria in biofilms.

The Use of Duplex Ultrasound in the Assessment of Arterial Supply to the Penis in Vasculogenic Impotence

Impotence may be caused by arterial disease affecting the vessels supplying the corpora cavernosa. Color duplex ultrasound was used to measure the peak systolic velocity and systolic rise time in the deep penile arteries in 22 impotent men following papaverine stimulation. The results were compared with the findings of selective internal pudendal pharmaco-arteriography. A further comparison was made using color duplex ultrasound with 37 impotent men who all responded well to papaverine. A systolic rise time of 110 msec. or more was found to be the best discriminant of disease in the arteries supplying the corpora giving a positive predictive value of 0.92. A long systolic rise time in a papaverine responder may indicate that the arterial supply is borderline or that the arterial flow is maximal and that the problem lies on the sinusoidal-venous side. It appears that in the absence of a pathological condition there is a large surplus arterial supply.

Outcome of transurethral prostatectomy for the palliative management of lower urinary tract symptoms in men with prostate cancer

Objective:  To investigate the efficacy of palliative transurethral prostatectomy (TURP) for lower urinary tract symptoms (LUTS) in men with prostate cancer.

Discontinuation rates and inter-injection interval for repeated intravesical botulinum toxin type A injections for detrusor overactivity

To report discontinuation rates, inter‐injection interval and complication rates after repeated intravesical botulinum toxin type A for the treatment of detrusor overactivity.

TRANSMISSION OF PENILE CUFF PRESSURE TO THE PENILE URETHRA

PURPOSE We developed a noninvasive method to measure voiding bladder pressure by inflating a penile cuff to interrupt flow. We tested the underlying assumption that cuff pressure is transmitted to the penile urethra. MATERIALS AND METHODS In 35 men we simultaneously recorded penile cuff and urethral pressure during 2 experimental protocols for 6 cuffs of various widths and manufactures. Initially a urethral pressure transducer was placed at the mid point of the cuff and urethral pressure was continuously recorded during cuff inflation. In experiment 2 cuff pressure was set at 120 cm. water and the urethral pressure profile was measured by withdrawing the urethral transducer through the cuff width. RESULTS There was excellent agreement of cuff with urethral pressure over the range of 0 to 200 cm. water for cuffs 37 to 54 mm. wide. Narrower cuffs showed wider variation with less efficient transmission of cuff pressure to the urethral lumen. Similarly maximum pressure in the urethral pressure profile showed best agreement for cuffs 38 and 46 mm. wide. Wider cuffs produced higher and narrower cuffs produced lower transmitted pressure within the urethra. Cuff performance was also related to penile size. Results had good within-subject repeatability. CONCLUSIONS We demonstrated that pressure transmission from cuff to urethra is optimal at a cuff width of 40 to 50 mm. and recommended this width for other investigations of noninvasive bladder pressure measurement.

Bladder Cancer Diagnosis and Identification of Clinically Significant Disease by Combined Urinary Detection of Mcm5 and Nuclear Matrix Protein 22

Background Urinary biomarkers for bladder cancer detection are constrained by inadequate sensitivity or specificity. Here we evaluate the diagnostic accuracy of Mcm5, a novel cell cycle biomarker of aberrant growth, alone and in combination with NMP22. Methods 1677 consecutive patients under investigation for urinary tract malignancy were recruited to a prospective blinded observational study. All patients underwent ultrasound, intravenous urography, cystoscopy, urine culture and cytologic analysis. An immunofluorometric assay was used to measure Mcm5 levels in urine cell sediments. NMP22 urinary levels were determined with the FDA-approved NMP22® Test Kit. Results Genito-urinary tract cancers were identified in 210/1564 (13%) patients with an Mcm5 result and in 195/1396 (14%) patients with an NMP22 result. At the assay cut-point where sensitivity and specificity were equal, the Mcm5 test detected primary and recurrent bladder cancers with 69% sensitivity (95% confidence interval = 62–75%) and 93% negative predictive value (95% CI = 92–95%). The area under the receiver operating characteristic curve for Mcm5 was 0.75 (95% CI = 0.71–0.79) and 0.72 (95% CI = 0.67–0.77) for NMP22. Importantly, Mcm5 combined with NMP22 identified 95% (79/83; 95% CI = 88–99%) of potentially life threatening diagnoses (i.e. grade 3 or carcinoma in situ or stage ≥pT1) with high specificity (72%, 95% CI = 69–74%). Conclusions The Mcm5 immunoassay is a non-invasive test for identifying patients with urothelial cancers with similar accuracy to the FDA-approved NMP22 ELISA Test Kit. The combination of Mcm5 plus NMP22 improves the detection of UCC and identifies 95% of clinically significant disease. Trials of a commercially developed Mcm5 assay suitable for an end-user laboratory alongside NMP22 are required to assess their potential clinical utility in improving diagnostic and surveillance care pathways.

The questionable benefit of multiple free-flow studies in men with lower urinary tract symptoms†

The diagnostic accuracy of maximum flow rate (Qmax) for bladder outlet obstruction (BOO) is limited. In a much-cited study, Reynard et al. concluded that diagnostic accuracy can be improved by taking the maximum Qmax of multiple flow rate measurements, observing that it may be more representative of the man’s usual Qmax. This conclusion was based on improved specificity from multiple voids. Yet this might also be achieved from a single void simply by lowering the threshold for classifying obstruction. We revisited the data published by Reynard et al. to compare diagnostic accuracy from the highest Qmax of multiple measurements, with that from a single measurement of Qmax.

Sacral nerve stimulation versus intravesical botulinum toxin injections for medically refractory overactive bladder: A contemporary review of UK treatment from both clinician and patients’ perspectives

Introduction: In the UK, 10,000 refractory overactive bladder patients per year receive intravesical onabotulinum toxin A treatment and 300 receive sacral nerve stimulation implants. Current National Institute for Health and Care Excellence guidelines propose using onabotulinum toxin A before sacral nerve stimulation whilst the European Association of Urology (EAU) and American Urological Association (AUA) suggests both be offered with equipoise. The aim of this study was to ascertain both patients and clinician views regarding these two treatments. Subjects/methods: Fifty consecutive overactive bladder patients who were refractory to behavioural and medical therapy anonymously completed a structured questionnaire about their treatment preferences. Additionally, 100 UK consultant urologists anonymously completed a separate questionnaire about their treatment preferences and which treatment modalities they had available for use in their Trusts. Results: Of patients, 60% preferred sacral nerve stimulation over onabotulinum toxin A, of whom 80% would happily randomise into a trial between the two treatments. Ninety-seven per cent of 100 consultant urologists in the UK have access to onabotulinum toxin A in their hospitals, but only 39% have access to sacral nerve stimulation. Of clinicians given access to all available options, 71% would use onabotulinum toxin A as their first choice treatment for refractory overactive bladder. Conclusion: There appears to be a significant disparity between current UK overactive bladder guidance, National Health Service accessibility to onabotulinum toxin A and sacral nerve stimulation therapies, the views of clinicians, and patient preferences for treatment. Level of evidence: 5

CorrespondenceUreteric colic and clinical evidence – Authors' reply

1 Pickard R, Starr K, MacLennan G, et al. Medical expulsive therapy in adults with ureteric colic: a multicentre, randomised, placebo-controlled trial. Lancet 2015; 386: 341–49. 2 Sur RL, Shore N, L’Esperance J, et al. Silodosin to facilitate passage of ureteral stones: a multi-institutional, randomized, double-blinded, placebo-controlled trial. Eur Urol 2015; 67: 959–64. 3 Furyk JS, Chu K, Banks C, et al. Distal ureteric stones and tamsulosin: a double-blind, placebo-controlled, randomized, multicenter trial. Ann Emerg Med 2015; published online July 17. DOI:10.1016/j. annemergmed.2015.06.001. 4 Gargon E, Williamson PR, Altman DG, Blazeby JM, Clarke M. The COMET Initiative database: progress and activities from 2011 to 2013. Trials 2014; 15: 279. 5 de la Rosette J, Laguna MP. Ureteric colic: evidence empowers responsible treatment. Lancet 2015; 386: 315–16. expulsive therapy and therefore we did not record this factor. We would expect, in view of the independent randomisation and full masking, that patients with uncomplicated dilatation were distributed evenly between study groups. We do not know whether the presence of dilatation differentially affected outcome between study groups in our trial. However, we would suggest that even if prognostic, this variable is not straightforward to measure on a CT of the kidneys, ureters, and bladder and is unlikely to be useful in routine care. With respect to our choice of outcome measure, we would maintain that need for further intervention was a highly relevant outcome for patients, urologists, and health-care planners, and was straightforward to measure. Placebo-controlled trials with imaging evidence of stone clearance showed overall proportions of 48% and 84% at 4 weeks. We suggest that seekers of evidence should consider the properties, relevance, and completeness of data collection for the primary outcome in each trial as part of their judgment of the worth of a trial in guiding clinical practice. Standardisation of outcome measures across trials is an important aim to allow valid and reliable synthesis of evidence. For urinary tract stone disease, this standardisation could be facilitated by international urological associations, as suggested in the Comment accompanying our paper. Finally, whilst we support the need for standardised (but relevant and easily measurable) outcome measures, we would maintain that unnecessarily restricting trial participation is not the way forward to establish the worth of novel interventions in routine clinical practice.