Quantifying bladder outflow obstruction in men:A comparison of four approximation methods exploiting large data samples

Introduction: A pressure flow study (PFS), part of the International Continence Society standard urodynamic test, is regarded gold standard for the classification and quantification of the urethral resistance (UR), expressed in the bladder outflow obstruction (BOO). For men with benign prostatic hyperplasia, the minimum urethral opening pressure (pmuo), found at the end of the passive urethral resistance relation is considered the relevant parameter describing BOO. However, in clinical practice, direct measurements of pmuo are easily confounded by terminal dribbling. For that reason, alternative methods were developed to derive pmuo, and thereby assess BOO using the maximum urine flow rate (Qmax) and the corresponding pressure (pdetQmax) instead. These methods were never directly compared against a large data set. With the increasing variety of treatments becoming available more precise grading of UR may become of relevance. The current study compares four well-known methods to approximate pmuo and examines the relation between pmuo and pdetQmax. Methods: In total, 1717 high-quality PFS of men referred with lower urinary tract symptoms between 2003 and 2020 without earlier lower urinary tract surgery were included. From these recordings, pmuo was calculated according to three one-parameter methods. In addition, a three-parameter method (3PM) was used, based on a fit through the lowest pressure flank of the pressure-flow plot. The estimated pmuo's were compared with a precisely assessed pmuo. A difference of &lt;10 cmH2O between an estimate and the actual pmuo was considered accurate. A comparison between the four approximation methods and the actual pmuo was visualized using a Bland–Altman plot. The differences between the actual and the estimated slope were assessed and dependency on pmuo was analyzed. Results: A total of 1717 studies were analyzed. In 55 (3.2%) PFS, 3PM analysis was impossible because all pressures after Qmax were higher than pdetQmax. The 3PM model was superior in predicting pmuo, with 75.9% of the approximations within a range of +10 or −10 cmH2O of the actual pmuo. Moreover, pmuo according to urethral resistance A (URA) and linearized passive urethral resistance relation (linPURR) appear equally reliable. Bladder outflow obstruction index (BOOI) was significantly less accurate when compared to all others. Bland–Altman analysis showed a tendency of BOOI to overestimate pmuo in men with higher grades of UR, while URA tended to underestimate pmuo in those cases. The slope between pmuo and pdetQmax-Qmax increased with larger pmuo, as opposed to the constant relation proposed within BOOI. Although significant differences were found, the clinical relevance of those differences is not known. Conclusion: Of the four methods to estimate pmuo and quantify BOO, 3PM was found the most accurate and BOOI the least accurate. As 3PM is not generally available and performance in lower quality PFS is unknown, linPURR is (for now) the most physiologically accurate.</p

Initial observation of the urodynamic pressure flow study — characteristics of bladder-neck or prostate median lobe dynamics during micturition

Purpose:: We present our observations of a urodynamic pressure flow study graph pattern that may be associated with bladder neck hypertrophy or prostate median lobe enlargement. Materials and Methods:: We report 23 male patients with signs and symptoms of lower urinary tract dysfunction who underwent urodynamic testing with pressure flow study analysis. We recognized an unusual pressure flow plot curve and found that these patients had cystoscopic evidence for bladder neck hypertrophy or cystoscopic or ultrasound evidence for prostate median lobe enlargement. Results:: The patients here demonstrated showed a pattern of increasing detrusor pressure on the pressure flow study — graph phase after maximum of flowrate, where a decreasing pressure pattern is expected. We contemplated that his pattern may show how bladder outflow dynamics is affected by the anatomical features of these patients and how patients may have symptoms of LUT dysfunction or significant residual urine despite a relatively good maximum flow rate. Conclusion:: We present a not previously described variation of the pressure flow study graph pattern common in men with prostatic hyperplasia, in a series of patients with median lobe prostatic hyperplasia and or hypertrophy of the bladder neck

ICS standaard : goed uitvoeren van urodynamisch onderzoek

In June 2017, in Neurourology and Urodynamics, the new ICS standard for good urodynamic practices was published. This article is the Dutch translation. This standard has been developed by an ad hoc working group, steered by the ICS Standardisation Steering Committee, with Werner Schaefer, Gunnar Lose, Howard B Goldman, Michael Guralnick, Sharon Eustice, Tamara Dickinson, Hashim Hashim and Peter Rosier

ICS standaard : goed uitvoeren van urodynamisch onderzoek

In June 2017, in Neurourology and Urodynamics, the new ICS standard for good urodynamic practices was published. This article is the Dutch translation. This standard has been developed by an ad hoc working group, steered by the ICS Standardisation Steering Committee, with Werner Schaefer, Gunnar Lose, Howard B Goldman, Michael Guralnick, Sharon Eustice, Tamara Dickinson, Hashim Hashim and Peter Rosier

Critical steps in developing professional standards for the International Continence Society

Aims: Standardization on the basis of systematic assessment of evidence has become an indispensable element of modern healthcare. International Continence Society (ICS) has initiated and produced extremely well cited standardization documents. The process of standardization is recently depicted in a published manuscript, to keep up with modern society healthcare demands. Methods: A narrative review of the ICS history and current state of standardizations for the terms, assessment and the management of patients with lower urinary tract dysfunction. Results: This article highlights the philosophy and the historical context of standardization and explains the core elements of modern day standardization. The article also demonstrates the scientific relevance of the ICS standards, on the basis of reference-counts. Conclusion: The history and the relevance of ICS standards are summarized

Basics of videourodynamics for adult patients with lower urinary tract dysfunction

Aims: Videourodynamics is the addition of imaging to invasive urodynamics and one of the methods to ensure objective diagnosis in persons with signs or symptoms of lower urinary tract dysfunction. This manuscript has the aim to outline the basics of the practice of videourodynamics and to elementary explain interpretation of the results. Methods: Literature sources and expert opinion were arranged to provide the reader with an introductory overview of current knowledge. Results: Videourodynamics was—like most diagnostics in health care—introduced on the basis of plausibility and expert conviction but has stood the test of time. Videourodynamics has, especially in patients with congenital or acquired neurogenic dysfunction of the lower urinary tract, undisputedly although not precisely quantifiable, added to (lower urinary tract) health care quality. Conclusion: The manuscript summarizes the basic elements of indication, practice, and interpretation of videourodynamics

Sensations reported during urodynamic bladder filling in spinal cord injury patients give additional important information

PURPOSE: This study investigated the sensations reported during filling cystometry in patients with spinal cord lesions (SCLs) of different levels and completeness. METHODS: In this retrospective cohort study, information was gathered on patients’ age and sex, cause of SCL, American Spinal Injury Association Impairment Scale (AIS), and lower urinary tract-related sensations in daily life. Filling cystometry (videourodynamics) was performed following the International Continence Society Good Urodynamic Practice Guidelines. In addition to bladder filling sensations (first sensation of bladder filling, first desire to void, strong desire to void), other sensations, such as detrusor overactivity related sensation and pain, were noted. RESULTS: In total, 170 patients were included (age, 45±17 years; 114 males and 56 females, 92 with complete and 78 with incomplete SCL). The test was done 6±4 years post-SCL. Sensation was reported by 57% of all patients. Half of the patients with complete SCL (46 of 92) had sensation, while 36% of those with incomplete SCL (28 of 78) reported no sensation. Bladder awareness was not predictable by the AIS. The filling sensations reported were equivalent to those given in the terminology of ICS. Pain was seldom present (6%, 10 of 170), and detrusor overactivity contraction was felt by 45 of 78 (58%). Very few patients used sensory information for bladder management at home. CONCLUSIONS: After SCL, most patients retained the ability to be aware of the lower urinary tract, and were assessable and gradable during urodynamic testing. The filling sensations were not different from those described in healthy individuals, but the number and sequence of the sensations were altered in a minority of patients. Pain and a sensation of unstable contractions gave additional important information. As different sensations relate to different spinal afferent pathways, the sensory evaluation during cystometry provided additional important information on the spinal cord’s condition

Are nomograms based on free uroflows helpful to evaluate urethral obstruction in men?

Aims: It was demonstrated earlier that reduced maximum flow-rate (Qmax) during intubated flow (IF) in women may be the consequence of a urethral reflex. Over-estimation of outflow obstruction is the consequence. Our hypothesis, that a similar phenomenon could occur in men, is tested using results of a free uroflow (FF) preceding an IF to eventually correct the Abrams-Griffiths (AG) number. Methods: Retrospectively, analysis of 441 urodynamic studies of men suspected of bladder outflow obstruction (BOO) was performed. The Valentini-Besson-Nelson model links outflow obstruction (parameter pucp) and the detrusor contractility (parameter k) to Qmax and detrusor pressure at Qmax (pdet.Qmax). AG and pucp are strongly correlated. Contractility is described by a graphical representation (a nomogram) which numerical fitting is an algebraic equation f(Qmax,pdet.Qmax). Nomograms based on IF allowed computing a calculated AG (corr-AG) on the basis of free flow. Results: Included files (N = 362) had filling volume during FF > 90 mL; corr-AG was compared to AG. When Qmax.FF > 1.5*Qmax.IF (N = 114), 61 patients (53.5%) were found less obstructed with corr-AG, no one more obstructed. Increased BOO could be the result of a urethral reflex during IF and AG gave an overestimation. When Qmax.FF < 1.5*Qmax.IF (N = 248), only 39 patients (12.1%) were found less obstructed with corr-AG and 28 (11.3%) more obstructed. Conclusion: To obtain a reliable evaluation of BOO in men, it is suitable to perform a FF before IF. A corrected AG (corr-AG) obtained from IF analysis and nomograms based on FF may be helpful for evaluation of BOO in men