# A Novel Intraurethral Device Diagnostic Index to Classify Bladder Outlet Obstruction in Men with Lower Urinary Tract Symptoms

Authors: Leonardo O. Reis; Guilherme C. Barreiro; Alessandro Prudente; Cleide M. Silva; José W. M. Bassani; Carlos A. L. D'Ancona
Journal: Advances in Urology
 (2009)

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## Abstract

Objectives. Using a urethral device at the fossa navicularis, bladder pressure during voiding can be estimated by a minimal invasive technique. This study purposes a new diagnostic index for patients with lower urinary tract symptoms (LUTSs). Methods. Fifty one patients presenting with LUTSs were submitted to a conventional urodynamic and a minimal invasive study. The results obtained through the urethral device and invasive classic urodynamics were compared. The existing bladder outlet obstruction index (BOOI) equation that classifies men with LUTSs was modified to allow minimal invasive measurement of isovolumetric bladder pressure in place of detrusor pressure at maximum urine flow. Accuracy of the new equation for classifying obstruction was then tested in this group of men. Results. The modified equation identified men with obstruction with a positive predictive value of 68% and a negative predictive value of 70%, with an overall accuracy of 70%. Conclusions. The proposed equation can accurately classify over 70% of men without resorting to invasive pressure flow studies. We must now evaluate the usefulness of this classification for the surgical treatment of men with LUTSs.


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## Body

## 1. Introduction

Invasive pressure flow studies (PFSs) in urodynamics are still the gold standard method
for objective classification of bladder outlet obstruction (BOO) in men with
lower urinary tract symptoms (LUTSs). It is able to delineate patients for successful
surgical approach [1], however, it is still costly, time-consuming,
and associated with significant morbidity.The
risks of complications after conventional urodynamic study in men with BOO are
greater, and acute urinary retention, macroscopic hematuria, urinary tract
infection, and/or fever can occur in over 19% of the cases [2].During
the past 14 years, many experts have raised minimal invasive possibilities as
substitutes [3, 4].Griffiths
et al. have previously described and validated a minimal invasive technique based on controlled inflation of a penile cuff during voiding [5]. Others had attempted other types of penile cuffs and condoms with insufficient results [3, 6–9].Trying to
overcome these limitations, we developed, in association with the University’s
Biomedical Engineering Department, a urethral device capable of extracting from
the voiding patient measurements comparable to those achieved from invasive PFS
[10].We have published before that applying logistic
regression fitting to the minimal invasive method utilizing this urethral
device was able to detect most patients with BOO [10]. However, the
conventional urodynamic assessment to be avoided, an equation as simple as
Abrams-Griffiths number [11] is necessary.


## 2. Material and Methods

The bladder outlet obstruction index (BOOI) was created
to classify men as obstructed, equivocal, or unobstructed based on invasive
urodynamic results ofpdet at Qmax and Qmax itself [12, 13].These were plotted on an equation and the BOOI obtained could differentiate the
three groups by a nomogram analysis (ICS nomogram) [11, 14, 15]:
(1)BOOI=(pdetatQmax)−(2×Qmax).Once logistic regression analysis has demonstrated 67% sensitivity and 79% specificity utilizing the novel intraurethral device to identify BOO [10], we developed a new equation from the comparison of the mathematical relationship between invasive pdet at Qmax and Qmax, and noninvasive piso and Qinterr results, respectively. Therefore, we included in the mathematical comparison all the new variables that the urethral device test introduced to the classical invasive measures.


### 2.1. Patients

After obtaining the Ethics Committee approval and
a written informed consent, sequential invasive and minimal invasive PFSs were
prospectively performed in men with clinical complaints of LUTS.


### 2.2. Invasive PFSs and Gold Standard Classification of Obstruction

PFS was performed according to ICS good
urodynamic practice guidelines [16], with the patients in
the standing position. A 6Fr double lumen urethral catheter was inserted for
filling and bladder pressure measurement, and a 6Fr rectal pressure line was
inserted for abdominal pressure measurement. External transducers were leveled
with the pubic symphysis and zeroed to atmospheric pressure. The bladder was
filled with physiological
saline at
50 mL∖minute until maximum
cystometric capacity. Flow was recorded by a load cell. The pdet at Qmax and Qmax was measured
on a computer display, using a cross-wire cursor and plotted on the ICS nomogram [11] to classify obstruction.


### 2.3. Minimal Invasive Urethral Device Test

The minimal invasive urodynamic evaluation was
done using a urethral device [10] especially designed in conical shape to be
adapted to the urethral meatus and fossa navicularis, with a side opening to
connect the pressure transducer and the other end free for the release of
urine/saline solution (Figure 1). The internal diameter of the device is 4 mm,
and the lower external diameter is 6 mm. It
consists of polyvinyl, carbon, and polytetrafluoroethylene,
making it light, non-distensible, and easy-to-sterilize.Figure 1
Actual urethral device used in the noninvasive test.After concluding the conventional urodynamic
assessment, the postvoid residual urine volume was measured. The bladder was
refilled with warm saline solution (37°C) at the same maximal cystometric
capacity, and the 6F urethral catheter was removed. This study was not blinded.
The urodynamic equipment used to register the conventional and minimal invasive
studies was the Dantec, Minuet Compact model.During voiding, the patient was instructed to
interrupt the flow with a digital maneuver that simply blocked the end of the
urethral device. Interrupted urine flow (Qinter) and isometric bladder pressure
(Piso) were registered using this technique. The rectal catheter used in the
conventional urodynamic assessment was maintained to record the Pabd. The Piso
was measured at the greatest pressure point after interrupted flow, and the
Qinter was considered the plateau: the greatest flow point resulted from the
impact of urine in the flow meter and was considered as interference [17, 18].


### 2.4. Analysis

These variables (Piso and Qinter) were
compared using the Pearson’s coefficient correlation test [19, 20] to
their correspondent measures obtained through invasive urodynamics, which were
pdet at Qmax and Qmax, respectively.As only two
variables demonstrated predictive ability in a previous analysis including all
variables (isometric pressure, abdominal pressure, maximal flow, Qinter, and
postvoid residual urine volume) [10], a binary result of obstructed versus nonobstructed,
obtained by grouping the Abrams-Griffiths classification, was done. The normal
and equivocal categories were combined as the nonobstructed group.We tried to find a function of minimal invasive
data to approximate (i.e., to classify), as closely as possible, the reference
standard classification. This
mathematical correlation was tested to determine substitute equivalents for an
adapted Abrams-Griffiths equation worth for minimal invasive measures.A
linear correlation between the minimal invasiveQinterr and invasive
Qmax as well as a quadratic relationship between the pressures piso and pdet at Qmax was demonstrated plotting on the
graph the correspondent variables. The numeric translation for these relations
is illustrated as follows:
(2)Qmax=a+(b×Qinterr),(3)pdetatQmax=a′+(b′×piso)+(c′×piso2).Thea and b parameters are estimated from the
simple linear regression on (2); and a′, b′ and c′ are parameters estimated from the multiple linear regression on (3).When we
substitute (2) and (3) into the original equation of Abrams-Griffiths for
invasive urodynamics (1), a new function to determine urinary outlet
obstruction through minimal invasive measures is described. The values obtained
using the urethral device test can be plotted on this new equation. The final
result was equivalent to the Abrams-Griffiths parameters for classification
upon invasive test, despite using minimal invasive measures. This equation was
able to distinguish the individuals into two different groups: obstructed,
equivocal/unobstructed. The sensitivity, specificity, positive predictive value
(PPV), and negative predictive value (NPV) were calculated for the minimal
invasive results in comparison to their invasive classification.All computations were done with Statistical
Analysis Systems (SAS Institute, Cary,
NC), version 8.2 [21].


## 2.1. Patients

After obtaining the Ethics Committee approval and
a written informed consent, sequential invasive and minimal invasive PFSs were
prospectively performed in men with clinical complaints of LUTS.


## 2.2. Invasive PFSs and Gold Standard Classification of Obstruction

PFS was performed according to ICS good
urodynamic practice guidelines [16], with the patients in
the standing position. A 6Fr double lumen urethral catheter was inserted for
filling and bladder pressure measurement, and a 6Fr rectal pressure line was
inserted for abdominal pressure measurement. External transducers were leveled
with the pubic symphysis and zeroed to atmospheric pressure. The bladder was
filled with physiological
saline at
50 mL∖minute until maximum
cystometric capacity. Flow was recorded by a load cell. The pdet at Qmax and Qmax was measured
on a computer display, using a cross-wire cursor and plotted on the ICS nomogram [11] to classify obstruction.


## 2.3. Minimal Invasive Urethral Device Test

The minimal invasive urodynamic evaluation was
done using a urethral device [10] especially designed in conical shape to be
adapted to the urethral meatus and fossa navicularis, with a side opening to
connect the pressure transducer and the other end free for the release of
urine/saline solution (Figure 1). The internal diameter of the device is 4 mm,
and the lower external diameter is 6 mm. It
consists of polyvinyl, carbon, and polytetrafluoroethylene,
making it light, non-distensible, and easy-to-sterilize.Figure 1
Actual urethral device used in the noninvasive test.After concluding the conventional urodynamic
assessment, the postvoid residual urine volume was measured. The bladder was
refilled with warm saline solution (37°C) at the same maximal cystometric
capacity, and the 6F urethral catheter was removed. This study was not blinded.
The urodynamic equipment used to register the conventional and minimal invasive
studies was the Dantec, Minuet Compact model.During voiding, the patient was instructed to
interrupt the flow with a digital maneuver that simply blocked the end of the
urethral device. Interrupted urine flow (Qinter) and isometric bladder pressure
(Piso) were registered using this technique. The rectal catheter used in the
conventional urodynamic assessment was maintained to record the Pabd. The Piso
was measured at the greatest pressure point after interrupted flow, and the
Qinter was considered the plateau: the greatest flow point resulted from the
impact of urine in the flow meter and was considered as interference [17, 18].


## 2.4. Analysis

These variables (Piso and Qinter) were
compared using the Pearson’s coefficient correlation test [19, 20] to
their correspondent measures obtained through invasive urodynamics, which were
pdet at Qmax and Qmax, respectively.As only two
variables demonstrated predictive ability in a previous analysis including all
variables (isometric pressure, abdominal pressure, maximal flow, Qinter, and
postvoid residual urine volume) [10], a binary result of obstructed versus nonobstructed,
obtained by grouping the Abrams-Griffiths classification, was done. The normal
and equivocal categories were combined as the nonobstructed group.We tried to find a function of minimal invasive
data to approximate (i.e., to classify), as closely as possible, the reference
standard classification. This
mathematical correlation was tested to determine substitute equivalents for an
adapted Abrams-Griffiths equation worth for minimal invasive measures.A
linear correlation between the minimal invasiveQinterr and invasive
Qmax as well as a quadratic relationship between the pressures piso and pdet at Qmax was demonstrated plotting on the
graph the correspondent variables. The numeric translation for these relations
is illustrated as follows:
(2)Qmax=a+(b×Qinterr),(3)pdetatQmax=a′+(b′×piso)+(c′×piso2).Thea and b parameters are estimated from the
simple linear regression on (2); and a′, b′ and c′ are parameters estimated from the multiple linear regression on (3).When we
substitute (2) and (3) into the original equation of Abrams-Griffiths for
invasive urodynamics (1), a new function to determine urinary outlet
obstruction through minimal invasive measures is described. The values obtained
using the urethral device test can be plotted on this new equation. The final
result was equivalent to the Abrams-Griffiths parameters for classification
upon invasive test, despite using minimal invasive measures. This equation was
able to distinguish the individuals into two different groups: obstructed,
equivocal/unobstructed. The sensitivity, specificity, positive predictive value
(PPV), and negative predictive value (NPV) were calculated for the minimal
invasive results in comparison to their invasive classification.All computations were done with Statistical
Analysis Systems (SAS Institute, Cary,
NC), version 8.2 [21].


## 3. Results

### 3.1. Patients

Fifty-one
consecutive male patients with complaints of lower urinary tract symptoms were
included in this study. Among these men, 46 (90%) were suitable for analysis, 5
(10%) were excluded due to involuntary high-amplitude detrusor contractions and
low bladder compliance during the invasive test.The
mean age was64.8±8.5 years (30 to 82). The prostate weight by digital rectal
examination was of 39.2±18.8g.The
mean international prostatic symptom score (IPSS) was14±6.9. The mean value for the normal patients (8,
range: 1–12) was lower
than those of the equivocal patients (13, range: 1–22) or obstructed
patients (13, range: 4–23). However, the
results of the analysis of variance were not significant (P=.14).The mean postvoid residual urine volume was 48.9 mL (range: 0–250). The mean
values of the normal patients (45 mL, range: 0–110) were lower
than those of the equivocal patients (60 mL, range: 0–250) or
obstructed patients (65 mL, range: 0–140). The
comparison of the mean postvoid residual urine volume between the groups with
the different urodynamic diagnoses was not statistically significant (P=.96).The urethral devices used in the minimal
invasive urodynamic evaluation did not cause pain during the procedure. Leakage
occurred between the urethra and the device in 1 patient, and the examination
was repeated.


### 3.2. Invasive Classification

Using invasive data, 21 (45.6%) were classified
as obstructed, 15 (32.6%) as equivocal, and 10 (21.7%) as unobstructed; a total of 25 (54.4%) of equivocal/unobstructed. When Pabd
was added to the statistical analysis, no additional patient was identified as
obstructed.


### 3.3. Minimal Invasive Results and Classification

Significant linear correlation was observed between invasiveQmax and minimal invasive Qinterr, r=0.558, P<.0001, and a quadratic polynomial correlation was observed between invasive pdet at Qmax and minimal invasive piso. Thus,
through simple linear regression for the urinary flow values and multiple
linear regression for the pressure values, we found the numeric equivalents
that substitute the variables in (2) and (3), as follows:
(4)Qmax=a+(b×Qinterr),wherea=2.007,b=0.627,
then,
(5)Qmax=2.007+(0.627×Qinterr),pdetatQmax=a′+(b′×piso)+(c′×piso2),wherea′=72.722,b′=−0.679,c′=0.004,
therefore,
(6)pdetatQmax=72.722+(−0.679×piso)+(0.004×piso2).This allowed for a mathematical substitution
of values on the Abrams-Griffiths original equation (1) [12] for the numeric
nonivasive correspondents achieved through these comparisons. Through
equivalent substitution, we reached
(7)BOOI=(pdetatQmax)−(2×Qmax),BOOI={72.722+(−0.679×piso)+(0.004×piso2)}−2×{2.007+(0.627×Qinterr)},BOOI=68.708−0.679×piso+0.004×piso2−1.245×Qinterr.This
was the final equation for classification of BOO using the urethral device
test, and the result was denominated urethral device number (UDn):
(8)UDn=68.8−0.68×piso+0.004×piso2−1.25×Qinterr.The final
result (UDn) classified each patient as obstructed or
equivocal/unobstructed, according to the ICS nomogram [11], which was not
modified.Of the
21 men classified as obstructed by Abrams-Griffiths
equation (conventional invasive urodynamic), 13 were identified by the minimal invasive
diagnostic index (Table1).Table 1
Comparison between Abrams-Griffiths equation (conventional invasive urodynamic) and minimal invasive diagnostic index.
Minimal invasive diagnostic indexConventional urodynamicNormal and equivocalObstructedNormal and equivocal1906Obstructed0813This new
equation classified 27 (58.7%) of the patients as equivocal/unobstructed and 19
(41.3%) as obstructed. Sensitivity was 61.9%; specificity, 76%; PPV, 68.4%; NPV,
70.37%. Overall accuracy was
69.6% (Table2).Table 2
Measurements of accuracy for obstruction through the new method.
Measurement%95% CIn/totalSensitivity61.938.7; 81.119/21Specificity76.054.5; 89.819/25Positive predictive value68.443.5; 86.413/19Negative predictive value70.449.7; 85.519/27Accuracy69.654.1; 81.832/46CI: confidence interval,n: number of patients.


### 3.4. Methodology Comparison

In order
to prove methodological equivalency, we tested the Pearson’s coefficient
correlation [19, 20] on the final results. The graphic correlation between the numeric BOOI and UDn for
each patient is demonstrated on Figure 2, r=0.653, P<.0001.Figure 2
Linear correlation tested through the Pearson’s coefficient between the number of Abrams-Griffiths (BOOI:y axis) and the urethral device number (UDn: x axis), r=0.653, P<.0001.


## 3.1. Patients

Fifty-one
consecutive male patients with complaints of lower urinary tract symptoms were
included in this study. Among these men, 46 (90%) were suitable for analysis, 5
(10%) were excluded due to involuntary high-amplitude detrusor contractions and
low bladder compliance during the invasive test.The
mean age was64.8±8.5 years (30 to 82). The prostate weight by digital rectal
examination was of 39.2±18.8g.The
mean international prostatic symptom score (IPSS) was14±6.9. The mean value for the normal patients (8,
range: 1–12) was lower
than those of the equivocal patients (13, range: 1–22) or obstructed
patients (13, range: 4–23). However, the
results of the analysis of variance were not significant (P=.14).The mean postvoid residual urine volume was 48.9 mL (range: 0–250). The mean
values of the normal patients (45 mL, range: 0–110) were lower
than those of the equivocal patients (60 mL, range: 0–250) or
obstructed patients (65 mL, range: 0–140). The
comparison of the mean postvoid residual urine volume between the groups with
the different urodynamic diagnoses was not statistically significant (P=.96).The urethral devices used in the minimal
invasive urodynamic evaluation did not cause pain during the procedure. Leakage
occurred between the urethra and the device in 1 patient, and the examination
was repeated.


## 3.2. Invasive Classification

Using invasive data, 21 (45.6%) were classified
as obstructed, 15 (32.6%) as equivocal, and 10 (21.7%) as unobstructed; a total of 25 (54.4%) of equivocal/unobstructed. When Pabd
was added to the statistical analysis, no additional patient was identified as
obstructed.


## 3.3. Minimal Invasive Results and Classification

Significant linear correlation was observed between invasiveQmax and minimal invasive Qinterr, r=0.558, P<.0001, and a quadratic polynomial correlation was observed between invasive pdet at Qmax and minimal invasive piso. Thus,
through simple linear regression for the urinary flow values and multiple
linear regression for the pressure values, we found the numeric equivalents
that substitute the variables in (2) and (3), as follows:
(4)Qmax=a+(b×Qinterr),wherea=2.007,b=0.627,
then,
(5)Qmax=2.007+(0.627×Qinterr),pdetatQmax=a′+(b′×piso)+(c′×piso2),wherea′=72.722,b′=−0.679,c′=0.004,
therefore,
(6)pdetatQmax=72.722+(−0.679×piso)+(0.004×piso2).This allowed for a mathematical substitution
of values on the Abrams-Griffiths original equation (1) [12] for the numeric
nonivasive correspondents achieved through these comparisons. Through
equivalent substitution, we reached
(7)BOOI=(pdetatQmax)−(2×Qmax),BOOI={72.722+(−0.679×piso)+(0.004×piso2)}−2×{2.007+(0.627×Qinterr)},BOOI=68.708−0.679×piso+0.004×piso2−1.245×Qinterr.This
was the final equation for classification of BOO using the urethral device
test, and the result was denominated urethral device number (UDn):
(8)UDn=68.8−0.68×piso+0.004×piso2−1.25×Qinterr.The final
result (UDn) classified each patient as obstructed or
equivocal/unobstructed, according to the ICS nomogram [11], which was not
modified.Of the
21 men classified as obstructed by Abrams-Griffiths
equation (conventional invasive urodynamic), 13 were identified by the minimal invasive
diagnostic index (Table1).Table 1
Comparison between Abrams-Griffiths equation (conventional invasive urodynamic) and minimal invasive diagnostic index.
Minimal invasive diagnostic indexConventional urodynamicNormal and equivocalObstructedNormal and equivocal1906Obstructed0813This new
equation classified 27 (58.7%) of the patients as equivocal/unobstructed and 19
(41.3%) as obstructed. Sensitivity was 61.9%; specificity, 76%; PPV, 68.4%; NPV,
70.37%. Overall accuracy was
69.6% (Table2).Table 2
Measurements of accuracy for obstruction through the new method.
Measurement%95% CIn/totalSensitivity61.938.7; 81.119/21Specificity76.054.5; 89.819/25Positive predictive value68.443.5; 86.413/19Negative predictive value70.449.7; 85.519/27Accuracy69.654.1; 81.832/46CI: confidence interval,n: number of patients.


## 3.4. Methodology Comparison

In order
to prove methodological equivalency, we tested the Pearson’s coefficient
correlation [19, 20] on the final results. The graphic correlation between the numeric BOOI and UDn for
each patient is demonstrated on Figure 2, r=0.653, P<.0001.Figure 2
Linear correlation tested through the Pearson’s coefficient between the number of Abrams-Griffiths (BOOI:y axis) and the urethral device number (UDn: x axis), r=0.653, P<.0001.


## 4. Comment

This idea was original and the device was designed in our institution;
therefore, this is the first report of this method.The analysis
of the IPSS of the patients in this study did not identify patients with BOO.
However, none of the patients presented with an IPSS of 28 or greater, a score
that has a positive correlation with obstruction [22].In this
study, no correlation was found between the postvoid residual urine volume and
BOO. Other studies have also failed to demonstrate this association [23, 24].The
probability of a urinary infection from the use of the urethral device is low
because it is introduced only up to the fossa navicularis, and it does not
cause pain.Other
techniques of noninvasive urodynamic evaluation have reported problems such as
elasticity in the condom catheter. Also, different types of material and different
sizes of the penile cuff can register a greater isometric pressure [25, 26].
These inconveniences were not observed with the urethral device although we
considered this technique minimal invasive.Because the
minimal invasive assessment was performed immediately after the conventional
assessment, a low variability was warranted as demonstrated before in the
second pressure/flow study of 192 patients with the diagnosis of BOO maintained
in 95.2% and reduced
only 6.9% in detrusor pressure at maximal urinary flow [27]. This variation,
although slight, was probably due to the reduced urethral resistance resulting from
successive voiding within a short period.The results
obtained revealed 67% sensitivity and 79% specificity, applying a logistic
regression [10], and 62% sensitivity and 76% specificity applying the new
equation fitting to the minimal
invasive method utilizing this urethral device to diagnose BOO.These results
are similar to those reported in other studies, in which the condom catheter
noninvasive urodynamic assessment was used to correctly diagnose 77% of the
patients who presented with obstruction [6]. It is important to note that 25.3% of the
patients in that study were excluded from the analysis because of problems such
as urine loss between the condom and penis (13 patients), faulty records (3 patients),
discomfort (2 patients), and the inability to urinate (1 patient). None of the
patients using the urethral device were excluded because of technical problems.The
noninvasive urodynamic study using a cuff also helped to separate the
obstructed from the unobstructed patients. The sensitivity and specificity rates
for the diagnosis of BOO in a study of 116 patients were 73% and 75%,
respectively [28]. The penile cuff is inconvenient, because it makes voiding
impossible for some patients, provokes urethral bleeding, and increases the
isometric bladder pressure [8].Griffiths et al. obtained comparable results, which were actually useful for only two
thirds of the patients previously considered suitable for this method (i.e.,
two thirds of 54% from the total recruited men). This limited result could
probably be due to the method itself, which did not differ a lot from the
simple flow rate criterion, in addition to the inconvenience of wearing a
penile cuff, which restricted the overall evaluation [5].The condom catheter and the penile cuff are
also not effective in identifying normal and equivocal patients [29]. This
suggests that a follow-up examination is necessary for these patients and,
depending on the outcome, a conventional urodynamic assessment should be
conducted.Differently from what has been done so far [5],
our hypothesis was that changes in the original equation could adapt minimal
invasive results, obtained with the urethral device, to the ICS nomogram. The
results would be eligible for classification on this nomogram, which was not
modified. The
subsequent prospective study demonstrated accordance between the proposed
minimal invasive and invasive classifications.Measures
obtained through the urethral device were comparable to the invasive
correspondents [10] and enabled the modification of the Abram-Griffiths
original equation [12]. The new formula can be applied to classify any other
individual submitted to the urethral device test.Taking
into account that data were obtained through different, though comparable,
methods, it was necessary to adequate parameters to use the standard
Abrams-Griffiths equation. The values of pressure and urinary flow measured
minimal invasive ultimately correlated to the invasive measures. This happens
because the minimal invasive method suffers external influences, such as
urethral compliance and abdominal pressure, which do not primarily affect the
direct measures achieved through invasive urodynamics [14, 15]. In spite of
using the same equation as a basis for minimal invasive classification of BOO,
there was a mathematical grant, since the errors observed between the two
methods were constant. This allowed for an equivalence represented by the new
equation (8).When we
apply the minimal invasive diagnostic index (UDn)
to the 50 patients analyzed in our previous study [10], the same 70% accuracy
was confirmed, showing this method validation.


## 5. Conclusions

The
urethral device test proved to be a promising substitute for invasive
evaluation of men presenting with LUTS after at least two different
methodologies and more than a hundred patients enrolled with over 70% accuracy
[10].Primary
results presented good correlation to the gold standard method, even though
there is still much to improve. It is an easily performed, acceptable method
located between the free simple flow rate criterion and PFS, and may represent
a reasonable option for BOO diagnosis in the near future.These
preliminary results need a greater number of men evaluated and the definition
of a final clinical use for its classification. It has not yet been proven if
the results could correlate with a good outcome after transurethral
prostatectomy. A prospective clinical study is under way to assess this new
method in relation to the outcome of elective prostatectomy [30, 31].



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*Source: 406012-2008-12-25.xml*