Passive Urethral Resistance Relation Research Articles

Constrictive versus compressive bladder outflow obstruction in men: Does it matter?

Bladder outflow obstruction (BOO) is a urethral resistance (UR) at a level above a clinically relevant threshold. UR is currently graded in terms of the existence and severity of the BOO based on maximum flowrate and associated detrusor pressure only. However, the pressure-flow relation throughout the course of voiding includes additional information that may be relevant to identify the type of BOO. This study introduces a new method for the distinction between the provisionally called compressive and constrictive types of BOO and relates this classification to underlying patient and urodynamic differences between those BOO types. In total, 593 high-quality urodynamic pressure-flow studies in men were included in this study. Constrictive BOO was identified if the difference Δp between the actual minimal urethral opening pressure (pmuo) and the expected pmuo according to the linearized passive urethral resistance relation (linPURR) nomogram was >25 cmH2O. Compressive BOO is identified in the complementary case where the pressure difference Δp ≤ 25 cmH2O. Differences in urodynamic parameters, patient age, and prostate size were explored. In 81 (13.7%) of the cases, constrictive BOO was found. In these patients, the prostate size was significantly smaller when compared to patients diagnosed with compressive BOO, while displaying a significantly lower maximum flowrate, higher detrusor pressure at maximal flowrate and more postvoid residual (PVR). This study is an initial step in the validation of additional subtyping of BOO. We found significant differences in prostate size, severity of BOO, and PVR, between patients with compressive and constrictive BOO. Subtyping of voiding-outflow dynamics may lead to more individualized management in patients with BOO.

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

A pressure flow study (PFS), part of the International Continence Societystandard 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 . In total, 1717 high-quality PFS of men referred with lower urinary tract symptoms between2003 and 2020 without earlierlower urinary tractsurgery 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 <10 cmH2 O 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. 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 cmH2 O 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. 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.

Flow resistive forces index (QRF): Development and clinical applicability assessment of a novel measure of bladder outlet resistance, aiming to enhance the diagnostic performance of uroflowmetry.

Currently, the diagnostic ability of uroflowmetry, the most widely used urodynamic test available for initial assessment of patients with lower urinary tract symptoms (LUTS), is considered limited by its inability to accurately discriminate between the underlying mechanisms of this condition. To improve the diagnostic accuracy of uroflow, we developed a mathematical formula that calculates the flow resistive forces index (QRF), a novel measure of bladder outflow/urethral resistance, and assessed its clinical applicability compared to the maximum flow rate (Qmax ). A cross-sectional observational study was conducted in a cohort of 61 adult men presenting with voiding dysfunction symptoms, who all underwent free uroflowmetry followed by pressure flow study. The development of the mathematical formula which contains five key uroflowmetry variables (voided volume, flow time, Qmax , average flow rate, and peak flow time) was based on the assumption that urine volume momentum changes during voiding, the concept of diphasic uroflow pattern (acceleration/deceleration), and the urethral resistance factor (URA) equation. Study subjects were classified either as obstructed or nonobstructed according to established urodynamic criteria (linearized passive urethral resistance relation, LinPURR; Abrams-Griffiths number, AGN [also called bladder outlet obstruction index, BOOI]; and URA). Univariate linear correlations, binary logistic regression model, and receiver operating characteristic (ROC) curve statistical analysis were employed (SPSS-22, MedCalc, GraphPad [P < .05]). Outflow obstruction was diagnosed in 50.8% (1 in 2) patients. Univariate analysis, and bivariate linear correlation, binary logistic regression, and ROC curve analyses showed that the QRF was a strong independent predictor of bladder outlet/outflow obstruction (BOO), significantly outperforming Qmax . QRF index accurately predicts BOO, significantly outperforming the currently widely used bladder outlet obstruction estimator Qmax . Despite potential study limitations (mainly small cohort size and lack of control group), we anticipate that with further study and proper clinical validation, QRF could become a valuable complement to uroflowmetry.

Effect of Aging on Storage and Voiding Function in Women with Stress Predominant Urinary Incontinence

We investigated age related changes in urodynamic parameters in 2 large cohorts of women planning stress urinary incontinence surgery. Using a standardized protocol we obtained urodynamic parameters for participants in SISTEr (Stress Incontinence Surgical Treatment Efficacy Trial) and TOMUS (Trial of Mid-Urethral Slings) undergoing baseline noninvasive flow followed by filling cystometrogram and pressure flow study. The bladder contractility index (defined as detrusor pressure at maximum flow+5×maximum flow) and detrusor hypocontractility (defined as detrusor pressure at maximum flow less than 10 cm H2O) were also characterized. Patients excluded from analysis had undergone prior stress urinary incontinence surgery or had prolapse stage greater than II. Propensity score analysis controlled for the potential bias of combining participants from 2 clinical trials. Linear and logistic regression analysis adjusting for propensity score quintile was done to assess the association of age and an age cutoff (less than 65 vs 65 or greater years) with urodynamic parameters. A total of 945 women (468 in SISTEr and 477 in TOMUS) were included in analysis. Mean age was 50 years in SISTEr (range 27 to 75) and 51 years (range 24 to 82) in TOMUS. Noninvasive maximum urinary flow decreased significantly with age (26.2 vs 22 ml per second, p=0.002). Noninvasive flow voiding time increased 2.7 seconds for each 10-year age increment and detrusor pressure at maximum flow decreased 2.1 cm H2O for each 10-year increase in age (each p=0.003). Hypocontractility was more likely in women 65 years old or older (OR 2.89, 95% CI 1.59, 5.27). The bladder contractility index was inversely related to age, decreasing a mean±SD of 7.68±1.96 cm H2O for each 10-year age increase (p<0.001). In these 2 cohorts the observed changes in voiding parameters suggest that detrusor contractility and efficiency decrease with age.

Diagnosis of Bladder Outlet Obstruction in Men Using a Near-infrared Spectroscopy Instrument as the Noninvasive Monitor for Bladder Function

To investigate the feasibility and accuracy of the diagnosis of bladder outlet obstruction (BOO) in men using near-infrared spectroscopy (NIRS) as a noninvasive monitor. The study included 94 patients with lower urinary tract symptoms owing to benign prostatic hyperplasia. All patients underwent uroflow rate and post-void residual (PVR) followed by NIRS assessment of BOO and pressure-flow study for diagnosis. The results of the NIRS were compared with that of the pressure-flow study. The data of 87 patients were finally enrolled in this study. According to the BOO judged by the NIRS, the 87 patients were divided into an obstruction group (52 cases) and a nonobstruction group (35 cases). The differences in the Abrams-Griffiths number, the linear passive urethral resistance relation value, and urethral resistance factor value between the 2 groups were significant (P ≤.001), indicating the practical significance of the NIRS method in the diagnosis of BOO. Further analysis showed the following: (1) the NIRS has a sensitivity of approximately 68.3%, specificity of 62.5%, and average diagnosis coincidence rate of 66.7% compared with the "gold standards"-Abrams-Griffiths number, and (2) the sensitivity (68.3%) and the coincidence rate (66.7%) of the NIRS diagnosis for BOO were significantly higher than the sensitivity (33.3%) and the coincidence rate (48.3%) of the examination method of free uroflow rate + PVR. Compared with the "maximum uroflow rate (Qmax) + PVR", NIRS can be more accurate and noninvasive for the diagnosis of BOO in men; this approach provides a new noninvasive method of high clinical value.

Resistive Index of Prostate Capsular Arteries: A Newly Identified Parameter to Diagnose and Assess Bladder Outlet Obstruction in Patients with Benign Prostatic Hyperplasia

We evaluated the association of the resistive index of the prostate capsular arteries and bladder outlet obstruction severity in men with benign prostatic hyperplasia. A total of 74 patients histologically diagnosed with benign prostatic hyperplasia were ultimately enrolled in this prospective study. Urodynamics were performed by a urologist to determine bladder outlet obstruction. Baseline parameters measured in patients with benign prostatic hyperplasia were the prostate capsular artery resistive index, International Prostate Symptom Score, quality of life score, total prostate and transition zone volume, and the transition zone index. ROC curves were produced to calculate the ROC AUC and evaluate the diagnostic performance of the prostate capsular artery resistive index, International Prostate Symptom Score, obstructive symptoms, total prostate and transition zone volume, and the transition zone index for bladder outlet obstruction. Significant difference between patients with and without bladder outlet obstruction was observed in the resistive index, which showed the highest coefficient with the degree of obstruction (r = 0.712, p <0.0001). At a cutoff of 0.69 the resistive index distinguished patients with and without bladder outlet obstruction with 78% sensitivity and 86.4% specificity. The prostate capsular artery resistive index had the maximum AUC of 0.823. The prostate capsular artery resistive index is significantly higher in patients with benign prostatic hyperplasia related bladder outlet obstruction than in those without such obstruction. The resistive index might serve as a novel indicator to diagnose and assess bladder outlet obstruction in patients with benign prostatic hyperplasia.

Is There a Role for Micturitional Urethral Pressure Profilometry in the Evaluation of Voiding Dysfunction in the 21st Century?

Complete urodynamic evaluation of a patient with voiding dysfunction should encompass the storage as well as voiding function of the bladder and the continence/flow-controlling zone of the urethra. Filling and voiding cystometry effectively depict the status of detrusor during the respective cycles. However, the status of the urethra cannot be directly measured by cystometry alone; nevertheless, it can provide indirect evidence for predicting incompetence during the stress phase (leak point pressures) and obstruction during the voiding phase (eg, pressure flow relations, Abrams-Griffiths number, detrusor-adjusted passive urethral resistance relation factor, obstruction coefficient) of the outlet. Fluoroscopic surveillance is often added to aid anatomic visualization of the urethra and, thus, the level of abnormality. However, the cost of set-up, radiation exposure, and obscure visualization in certain conditions are likely to limit its use. Urethral pressure profilometry (UPP) is the most direct method to measure urethral pressures during the filling and voiding phases. The concept of UPP is based on sound physical principles and has been well-researched ex vivo and in vivo. The principle is that during flow down a collapsible tube, there is a decrease in hydrostatic pressure across the site of any narrowing. Unlike the set-up of a videofluoroscopy unit, that of UPP is not elaborate, other than a special double/triple lumen urethral pressure catheter and an additional pressure transducer. However, it does have a learning curve that is steeper than that of pressure flow study. Nevertheless, once understood, it is simple, reproducible, and accurate. In the current era, more enthusiasm and research are required in this field lest the technique be written off.

Clinical significance of B-mode ultrasound found bladder trabeculation in BPH patients

Objective To study the role of B-mode ultrasound found bladder trabeculation in evaluating the degree of bladder outlet obstruction (BOO) and the bladder function in benign prostatic hyperplasia (BPH) patients.Methods Conducted prospective research to determine differences in clinical data and urodynamic parameters between BPH patients with and without bladder trabeculation diagnosed by abdominal ultrasound.Results Thirty-six BPH patients with bladder trabeculation were compared with 68 BPH patients without bladder trabeculation.The mean age was (73.7 ± 10.1 ) years for the patients with bladder trabeculation and ( 69.6 ± 6.2 ) years without bladder trabeculation, IPSS was 24.4 ± 6.6 and 22.8 ± 8.3 respectively, in which no significant differences were found ( P ＞ 0.05 ).The detrusor pressure at maximum flow rate was ( 131.7 ± 57.3 ) cm H20 and (92.1 ± 47.8 )cm H2O ) respectively.The linearized passive urethral resistance relation was 4.6 :± 1.1 and 3.5 ± 1.5 respectively, showing a significant difference ( P ＜.05 ) between the two groups.Seventy-two point two percent (26/36) of the patients with bladder trabeculation had a low compliance bladder, among whom 23.1% (6/26) of the patients had bilateral hydronephrosis with renal insufficiency.The percentage for the control group was 42.6% (29/68) and 10.3% (3/29) respectively (P ＜ 0.05).Conclusions The bladder trabeculation found by B-ultrasound in BPH patients suggests the existence of BOO and a high risk of bilateral hydronephrosis.Bladder trabeculation in patients without urinary retention suggests they are in compensation status.Relief of the obstruction is helpful to recovery of bladder function and the reduction of complications. Key words: Benign prostatic hyperplasia; Bladder outlet obstruction; Bladder trabeculation; Ultrasonography

Is the ultrasound‐estimated bladder weight a reliable method for evaluating bladder outlet obstruction?

• To evaluate the correlation between ultrasound-estimated bladder weight (UEBW) in patients with different degrees of bladder outlet obstruction (BOO). • We evaluated 50 consecutive non-neurogenic male patients with lower urinary tract symptoms (LUTS) referred to urodynamic study (UDS). All patients self-answered the International Prostate Score Symptoms (IPSS) questionnaire. After the UDS, the bladder was filled with 150 mL to determine UEBW. • Patients with a bladder capacity under 150 mL, a previous history of prostate surgery or pelvic irradiation, an IPSS score <8, a bladder stone or urinary tract infection were excluded. • After a pressure-flow study, the Schafer linear passive urethral resistance relation nomogram was plotted to determine the grade of obstruction: Grades I-II/VI were defined as mild obstruction, Grades III-IV/VI as moderate obstruction, and Grades V-VI/VI as severe obstruction. • The UEBW was 51.7 ± 26.9, 54.1 ± 30.0 and 54.8 ± 28.2 in patients with mild, moderate and severe BOO, respectively (P= 0.130). The UEBW allowed us to define four groups: (i) UEBW <35 g; (ii) 35 g ≤ UEBW < 50 g; (iii) 50 g ≤ UEBW < 70 g; and (4) UEBW ≥ 70 g. • We did not find any differences in age, prostate weight, IPSS, PVR, cystometric bladder capacity, presence of detrusor overactive and degree of obstruction in the aforementioned groups. • Despite the fact that some studies have emphasized the value of UEBW as an efficient non-invasive method for evaluating lower urinary tract obstruction, our study suggests that UEBW does not present any individual correlation with LUTS or objective measurements of BOO.

The Diagnostic Accuracy and Lower Cutoff Value of Three Methods for Quantifying Urethral Resistance in Men

Introduction: We estimated the diagnostic accuracy of Abrams-Griffiths number (AG), urethral resistance factor (URA) and detrusor-adjusted mean passive urethral resistance relation factor (DAMPF) for bladder outlet obstruction (BOO) in benign prostate hyperplasia (BPH) patients. Materials and Methods: AG, URA and DAMPF were obtained by pressure-flow studies from BPH patients. Receiver operating characteristic (ROC) curves were used to analyze the diagnostic accuracy of the AG, URA and DAMPF in the diagnosis of BOO. Results: Among the 172 cases there were 154 classified as obstructed (89.5%) and 18 as unobstructed (10.5%). There were statistically significant differences in AG, URA and DAMPF between the obstructed and the unobstructed cases. The ROC curve demonstrated a similar diagnostic accuracy in the diagnosis of BOO for AG and URA values, and the least was seen for the DAMPF value. An AG cutoff of >33 provided a sensitivity of 89.61% and a specificity of 100%. A URA cutoff of >28 provided a sensitivity of 91.56% and a specificity of 100%. A sensitivity of 93.51% and the weakest specificity of 77.78% were recorded for DAMPF values of >52. AG and URA had a similar accuracy, while the efficacy of DAMPF is significantly lower in the diagnosis of BOO. Conclusions: AG or URA appeared to be the best discriminating parameters of BOO in BPH patients. The DAMPF could be used to aid the BOO diagnosis. Lower cutoff values were suggested for these BOO parameters.

Treatment Strategy According to Findings on Pressure-Flow Study for Women with Decreased Urinary Flow Rate

Purpose. In women who reported a weak urinary stream, the efficacy of treatment chosen according to the urodynamic findings on pressure-flow study was prospectively evaluated. Materials and Methods. Twelve female patients with maximum flow rates of 10 mL/sec or lower were analyzed in the present study. At baseline, all underwent pressure-flow study to determine the degree of bladder outlet obstruction (BOO) and status of detrusor contractility on Schäfer's diagram. Distigmine bromide, 10 mg/d, was given to the patients with detrusor underactivity (DUA) defined as weak/very weak contractility, whereas urethral dilatation was performed using a metal sound for those with BOO (linear passive urethral resistance relation 2–6). Treatment efficacy was evaluated using the International Prostate Symptom Score (IPSS), uroflowmetry, and measurement of postvoid residual urine volume. Some patients underwent pressure-flow study after treatment. Results. Urethral dilatation was performed for six patients with BOO, while distigmine bromide was given to the remaining six showing DUA without BOO. IPSS, QOL index, and the urinary flow rate were significantly improved in both groups after treatment. All four of the patients with BOO and one of the three with DUA but no BOO who underwent pressure-flow study after treatment showed decreased degrees of BOO and increased detrusor contractility, respectively. Conclusions. Both BOO and DUA cause a decreased urinary flow rate in women. In the short-term, urethral dilatation and distigmine bromide are efficacious for female patients with BOO and those with DUA, respectively.

Cross-sectional and longitudinal studies on interaction between bladder compliance and outflow obstruction in men with benign prostatic hyperplasia

To explore the interaction between bladder compliance (BC) and bladder outflow obstruction (BOO) in men with benign prostatic hyperplasia (BPH) using cross-sectional and longitudinal studies. A total of 181 men with BPH were recruited, and 100 of them were followed for one year. Cystometry was performed in a standing or a sitting position with 30 mL/min infusion. BC was manually corrected and defined. Obstruction coefficient (OCO), linear passive urethral resistance relation and international continence society (ICS) nomogram were used to diagnose BOO. The obstructed parameters were compared between the reduced BC group and the non-reduced group. BC was compared between the first investigation at the beginning of study and the second investigation at the end of study during the one-year follow-up period. The group with reduced BC had increased OCO and linear passive urethral resistance relation. BC was significantly lower in the obstructed group (55.7 mL/cm water) than that in unobstructed and equivocal one (74.9 mL/cm water, P <0.01). BC gradually reduced with the increased obstructed grade. There was a significantly weak negative correlation between BC and OCO (r = -0.132, P < 0.01). Over the one-year follow-up period in the longitudinal study, BC for all men changed from 54.4 to 48.8 mL/cm water (P >0.05), and BC for the group with BOO fell from 58.4 +/- 70.1 to 46.5 +/- 38.7 mL/cm water (P>0.05). In men with BPH, a significant systematic decrease occurred in BC in the obstructed group and a significant systematic increase with urethral resistance occurred in the low BC group. A longitudinal study of the tendency of BC reduction in a group with BOO is necessary in the future.

Urodynamics after TURP and HoLEP in urodynamically obstructed patients: Are there any differences at 1 year of follow-up?

Objectives To compare urodynamic findings after holmium laser enucleation of the prostate (HoLEP) and transurethral resection of the prostate (TURP) for the treatment of benign prostatic hyperplasia-related bladder outlet obstruction. Methods From January to October 2002, 100 consecutive patients with benign prostatic hyperplasia with obstructive lower urinary tract symptoms were randomized to surgical treatment with either HoLEP (group 1, n = 52) or TURP (group 2, n = 48). All patients were preoperatively assessed using the International Prostate Symptom Score and quality-of-life question, total serum prostate-specific antigen measurement, transrectal ultrasonography, and complete urodynamic study. The operative time, catheterization time, and overall hospital stay were also recorded for both groups. All patients were assessed at 1, 6, and 12 months postoperatively using a complete urodynamic evaluation. Results All patients were obstructed preoperatively (Schäfer grade greater than 2). Both groups were comparable in terms of age, total serum prostate-specific antigen level, International Prostate Symptom Score, and urodynamic results. At 1, 6, and 12 months of follow-up, no statistically significant differences were recorded in terms of detrussor pressure at maximal urinary flow rate, Schäfer grade (linear passive urethral resistance relation), maximal urinary flow rate, International Prostate Symptom Score, and quality-of-life score. In the HoLEP group, the catheterization time and hospital stay were significantly shorter. Transitory lower urinary tract symptoms after 3 months of follow-up and dysuria were more frequent in the HoLEP group than in the TURP group, although at 12 months of follow-up, the results were comparable. Conclusions Both HoLEP and TURP were equally effective in relieving bladder outlet obstruction. Although associated with greater early self-resolving irritative symptoms, HoLEP can guarantee a shorter catheterization time and hospital stay with longer operative times, proposing itself as an attractive alternative to standard TURP.

Correlations of Urodynamic Changes With Changes in Symptoms and Well-being After Transurethral Resection of the Prostate

Correlations of Urodynamic Changes With Changes in Symptoms and Well-being After Transurethral Resection of the Prostate

Urodynamic Effects of Terazosin Treatment for Japanese Patients With Symptomatic Benign Prostatic Hyperplasia

For treating benign prostatic hyperplasia (BPH) 5 or 10 mg. terazosin hydrochloride daily has been routinely used in North America and Europe. We investigated the urodynamic effects of 2 mg. terazosin daily on Japanese patients with symptomatic BPH using pressure flow study. A total of 20 Japanese patients 50 years old or older with symptomatic BPH underwent symptomatic and urodynamic evaluations, including pressure flow study, before and after terazosin treatment. Patients were given 1 mg. terazosin once daily for the first 7 days and they continued to receive 1 mg. terazosin twice daily for the following 3 weeks. At 4 weeks after terazosin treatment the International Prostate Symptom Score, quality of life index and maximum and average flow rates were significantly improved. Pressure flow study demonstrated decreased detrusor pressure at maximum flow, and minimum detrusor pressure during voiding and urethral resistance factor after terazosin treatment. Of the 20 patients 13 (65%) showed improvement in the linear passive urethral resistance relation. There was no significant difference in the maximum W. factor before and after terazosin treatment. Terazosin treatment, even 2 mg. daily, urodynamically relieved bladder outlet obstruction in Japanese patients with symptomatic BPH without any changes in detrusor contractility.

Relationship between the Shape of Passive Urethral Resistance Relation and Prostatic Histology in Patients with Bening Prostatic Hyperplasia

We assessed the relationship between the type of passive urethral resistance relation (PURR) and prostatic histology in 28 patients with benign prostatic hyperplasia (BPH), who underwent transurethral resection of the prostate. PURR was classified into three types according to pressure-flow plots, and resected specimens were analyzed by quantitative morphometry. Patient age, prostatic volume and the area densities of each histological component did not show significant differences among the three groups. However, there was a trend to correlation between prostates with a high glandular component and urethral compliance. Further studies of larger populations are needed to validate this assumption.

New simple method of transabdominal ultrasound to assess the degree of benign prostatic obstruction: size and horizontal shape of the prostate.

Transabdominal ultrasound has been the standard clinical tool for evaluating prostatic size; however, the severity of benign prostatic obstruction does not always correspond to the size of the prostate. The purpose of this study was to consider the utility of two parameters, (i) the prostatic volume (Pvol) and (ii) the ratio of the height : width of the maximum horizontal section of prostate (H : W) obtained by transabdominal ultrasound, in screening the degree of benign prostatic obstruction. The results were compared with the linear passive urethral resistance relation (lin-PURR) obtained by pressure-flow studies. Fifty-one men with lower urinary tract symptoms were prospectively evaluated in regard to urodynamic parameters, transabdominal ultrasound volume of the prostate, and calculation of lin-PURR. A significant positive correlation was found between Pvol and the degree of benign prostatic obstruction. When the ultrasonographic parameters of greater than 30 mL Pvol and 0.8 H : W were adopted as provisional cut-off points for detecting patients with obstruction, the selected 10 cases had lin-PURR > 3. In addition, there were six cases classified with lin-PURR >or= 3 despite the fact that their Pvol was less than 30 mL. Their H : W values were > 0.8. Transabdominal ultrasound is useful as a screening test for evaluating the prostate. In addition to the size of the prostate, the parameter of the horizontal shape (H : W ratio) makes an assessment of the degree of benign prostatic obstruction more reliable.

Comparison of long-term results of transurethral incision of the prostate with transurethral resection of the prostate, in patients with benign prostatic hypertrophy

One hundred patients with benign prostatic hypertrophy (BPH) were randomized to transurethral incision (TUIP) or transurethral resection of the prostate (TURP). The average prostate weight before operation was not more than 30.0 g. Indications for the operations were based on the disease history, physical examination, digital rectal examination, laboratory values, and pressure-flow examination. All operations were performed with patients under spinal anesthesia. TUIP was performed with a Collins knife, and TURP was performed with a resectoscope. Follow-up was performed 24 months after the operations. After treatment there were statistically significant daytime and nocturnal reduction in voiding frequencies of 2.9 and 1.7, respectively, after TUIP, and 2.0 and 1.5 after TURP. In both groups, there occurred significantly better maximal flow rate from 7.6 mL/s to 16.9 mL/s in group I and from 6.9 mL/s to 17.6 mL/s in group II. The mean values of linearized passive urethral resistance relation in both groups significantly decreased from 3.6 ± 0.6 to 1.0 ± 0.5 after TUIP and from 3.9 ± 04 to 1.4 ± 0.5 after TURP. The TUIP procedure is effective and safe for patients with a small number of complications. Neurourol. Urodynam. 21:112–116, 2002. © 2002 Wiley-Liss, Inc.

Acute urinary retention: defining the need and timing for pressure-flow studies.

To investigate the utility of "late" pressure-flow studies in predicting the outcome of prostatectomy for acute urinary retention. Fifty-eight patients with acute urinary retention were prospectively assessed using the International Prostate Symptom Score and pressure-flow studies at a median (range) of 24 (13-60) days after the episode of retention, and before transurethral resection of the prostate. Bladder outlet obstruction and bladder contractility were graded using a modified adaptation of Schäfer's passive urethral linear resistance relation. Fifty-six (97%) patients generated a voluntary detrusor contraction, with a mean (range) detrusor pressure at maximum flow of 72.7 (5-144) cmH2O, and 43 (75%) patients were deemed to be obstructed. Eight (16%) patients failed to void after prostatectomy and required clean intermittent catheterization. There were statistically significant differences between successful and unsuccessful patients in mean (SD) age, at 66.30 (6.9) vs 78.8 (2.6) years (P = 0.001), detrusor instability (49% vs 0%, P = 0.01), inability to void during pressure study (8% vs 75%, P = 0.001), and maximal detrusor pressure in the voiding phase, at 80 (36.0) vs 19 (11.2) cmH2O (P = 0.001). In patients with acute urinary retention, pressure-flow studies undertaken after a period of adequate bladder rest (> 3 weeks) are useful in predicting the surgical outcome. Old age, absence of bladder instability, inability to void during the pressure-flow study and a maximal detrusor pressure of < 20 cmH2O are associated with a poor outcome after prostatectomy.

PRESSURE FLOW STUDY DATA IN A GROUP OF ASYMPTOMATIC MALE CONTROL PATIENTS 45 YEARS OLD OR OLDER

The role of pressure flow studies in the routine evaluation of patients with benign prostatic hyperplasia remains a controversial issue in urological practice. There are little data on age matched asymptomatic control groups. We evaluated pressure flow findings in such a group. A total of 24 male patients 47 to 80 years old (mean age 62.5) attending a general surgical clinic were recruited for study after ethical committee approval. The volunteers had never sought medical attention for urinary symptoms and did not perceive themselves as having a urological problem. Volunteers were assessed by International Prostate Symptom Score (I-PSS) and Madsen symptom score, clinical examination, free uroflowmetry, post-void residual ultrasound, repeat pressure flow studies and transrectal ultrasonography. Pressure flow tracings were manually analyzed for standard urodynamic values and the degree of bladder outflow obstruction according to recognized International Continence Society, Abrams-Griffith nomogram, linear passive urethral resistance relation and urethral resistance factor classifications. Median I-PSS was 2.0 (interquartile range 1.2 to 5.7). For I-PSS quality of life the median was 1.0 (interquartile range 0.75 to 2.0). On pressure flow studies 3 patients (13%) had unequivocal obstruction, 7 (29%) were in the equivocal area and 14 (58%) had no obstruction, while 15 (63%) had unstable contractions on medium fill cystometry. The data show that a surprising number of apparently normal men are obstructed by commonly used criteria. This finding confirms asymptomatic obstruction, suggesting that obstruction may be less important in the development of symptoms than previously thought. Also, until the natural history of obstruction is more clearly defined surgery in obstructed asymptomatic patients is probably unwise.