Dynamic Testing

110 Pages·2009·0.9 MB·English

Committee 6
Dynamic Testing
Chairman
G. HOSKER (U.K)
Members
P. ROSIER (The Netherlands),
J. GAJEWSKI (Canada),
P. SAND (USA)
Consultants
L. SZABO (Hungary),
A. CAPEWELL (U.K)
413
CONTENTS
F. ANORECTAL PHYSIOLOGY
A. INTRODUCTION
STUDIES
G. SUMMARY OF
RECOMMENDATIONS FOR
B. URODYNAMICS
CLINICAL PRACTICE RELATING
TO ANORECTAL PHYSIOLOGY
STUDIES
C. URODYNAMICS: NORMAL
VALUES, RELIABILITYAND
H. ACKNOWLEDGEMENTS
DIAGNOSTIC PERFORMANCE
D. CLINICALAPPLICATIONS OF REFERENCES
URODYNAMIC STUDIES
E. SUMMARY OF
RECOMMENDATIONS FOR
CLINICAL PRACTICE
RELATING TO URODYNAMICS
414
Keywords
The following are the words and phrases that were used by rectal balloon
the committee members in their search of the literature. rectal barostat predicts
PubMed was the source predominantly used by all the rectal barostat specificity
committee members. rectal compliance
anal canal length rectal compliance predicts
anal contraction duration rectal compliance specificity
anal electrosensitivity rectal distension
anal fatigability rectal electrosensitivity
anal high pressure zone rectal mucosal sensory
anal manometry rectal saline retention test
anal manometry normal rectal sensation
anal mucosal sensory rectoanal inhibitory reflex
anal mucosal testing rectoanal pressure gradient
anal pressure rest reliability and reproducibility of urodynamics
anal resting tone repeatability anal squeeze
anal sensitivity repeatability manometry
anal sphincter endurance repeatibility anal squeeze
anal sphincter fatigue repeatibility manometry
anal squeeze duration reproducibility anal
anal squeeze endurance reproducibility manometry
anal squeeze pressure reproducibility resting
anal squeeze pressure sensitivity reproducibility squeeze pressure
anal squeeze pressure specificity resting anal pressure
anal tone resting anal pressure discrimination
anorectal manometry resting anal pressure discriminator
anorectal manometry normal resting anal pressure following
barostat resting anal pressure predicts
basal anal pressure resting anal pressure sensitivity
basal sphincter pressure resting anal pressure sensitivity
bladder exstrophy resting anal pressure specificity
bristol stool resting pressure sensitivity
cerebral palsy resting pressure specificity
digital anal contraction pressure sacral agenesis
digital anal manometry saline continence test
digital basal anal pressure saline enema test
digital basal pressure saline infusion test
digital resting anal pressure saline retention test
digital resting pressure spinal cord injury
digital squeeze pressure spine bifida
duration squeeze pressure squeeze pressure following
ectopic ureterocele squeeze pressure predict
external anal sphincter stool chart
external sphincter endurance stool consistency
external sphincter fatigue temperature anal mucosa
faecal consistency thermal anal
fecal consistency thermal rectal
high pressure zone thermal rectal mucosa
imperforate anus urethral stricture
incontinence variability anal
internal anal sphincter variability anal squeeze
maximal squeeze pressure variability basal
maximum squeeze pressure variability manometry
mucosal sensitivity variability resting
myelodysplasia variability sphincter
neurogenic bladder dysfunction vectography
nocturnal enuresis vectography ultrasound
normal anal squeeze pressure vector manometry
normal basal pressure vector manometry ultrasound
normal resting pressure vector volume
normal sphincter pressure vector volume ultrasound
normal squeeze pressure vesicoureteral reflux
occult spinal dysraphism
posterior urethral valves (urinary AND incontinen*) AND ((urge* OR overactiv*) OR
pudendal nerve latencies stress) AND (urethr* AND leak OR press* OR valsal*) OR
pudendal nerve latency urodynam*
415
Abbreviations
ALPP abdominal leak point pressure MCC maximum cystometric capacity
ANCOVA analysis of covariance MES mucosal electrosensitivity
APV anal pressure vectography MS multiple sclerosis
ARM anorectal malformation MUCP maximum urethral closure
ARPS anorectal physiology studies pressure
AUS artificial urinary sphincter MUP maximum urethral pressure
AVP anal pressure vectography NDO neurogenic detrusor
BOO bladder outlet obstruction overactivity
BOOI bladder outlet obstruction index NDV normal desire to void
BPE benign prostatic enlargement NICE National Institute for Health and
BPH benign prostatic hyperplasia Clinical Excellence
BPO benign prostatic obstruction NPV negative predictive value
BPS bladder painful syndrome OAB overactive bladder
CLPP cough leak point pressure POP pelvic organ prolapse
CMAP compound muscle action PNTML pudendal nerve terminal motor
potential latency
DHIC detrusor hyperactivity with PPV positive predictive value
impaired contractile function
PVP photoselective laser
DLPP detrusor leak point pressure vaporisation prostatectomy
DO detrusor overactivity
PVR post-void residual urine
DOI detrusor overactivity (volume)
incontinence
QoL quality of life
EMG electromyogram/
RAIR recto-anal inhibitory reflex
electromyography
SCI spinal cord injury
FDV first desire to void
SD standard deviation
FSF first sensation of filling
SDV strong desire to void
FUL functional urethral length
SEM standard error of the mean
GI gastrointestinal
SPT specificity
HPZ high pressure zone
STV sensitivity
ICI International Consultation on
SUI stress urinary incontinence
Incontinence
TURP transurethral resection of the
ICS International Continence
prostate
Society
TVT tension-free vaginal tape
IDC involuntary detrusor
contraction(s) UDS urodynamic studies
IDO idiopathic detrusor overactivity UPP urethral pressure profile/
IPAA ileal pouch anal anastomosis profilometry
IPSS International Prostate Symptom UPR urethral pressure reflectometry
Score URP urethral retro-resistance
IQR interquartile range pressure
ISD intrinsic sphincter deficiency USI urodynamic stress urinary
IWT ice water test incontinence
LPP leak point pressure UUI urgency urinary incontinence
LUT lower urinary tract VLPP Valsalva leak point pressure
LUTD lower urinary tract dysfunction VUR vesico-ureteric reflux
LUTS lower urinary tract symptoms VV voided volume
416
Dynamic Testing
G. HOSKER
P. ROSIER, J. GAJEWSKI, P. SAND
L. SZABO, A. CAPEWELL
be dealt with by an integrated approach by future
consultations. However, although the two topics clearly
A. INTRODUCTION
have much in common with regard to both patho-
physiological mechanisms and clinical application,
this committee thought it was appropriate to continue
The first two reports of the International Consultation to address the two topics separately in this report.
on Incontinence (ICI) contained chapters on
Therefore, following this introduction, the chapter
“Urodynamic Testing”[1, 2]. Urodynamics is the
firstly considers urodynamics before considering
umbrella term used to describe measurements of the
dynamic testing for anal incontinence. For each, the
function of the lower urinary tract. These
tests are described and then there is a review of data
measurements can be used in the management of
about normal values and reliability of the measured
urinary incontinence. The third report of the ICI
parameters. This is followed by reviews of the literature
expanded this topic to include physiological
regarding clinical urodynamic evaluation of different
measurements of the lower gastrointestinal tract.
patient groups with urinary incontinence (women,
These measurements can be used in the management
men, children, neurogenic dysfunction, and the frail
of faecal or anal incontinence. Consequently, the
elderly). This is followed by reviews from the literature
chapter was then renamed ‘Dynamic Testing’. [3]
regarding the clinical evaluation of patients with anal
This is the successor to that chapter and, in this fourth incontinence. Each section concludes with the
consultation, we have further updated the evidence committee’s recommendations regarding dynamic
for the technical performance, clinical utility and testing.
responsiveness to treatment of these measurements.
We have used the chapter on ‘Dynamic Testing’from
the previous consultation as a template for this report;
retaining some of the original text and tables where
there has been no change since the previous B. URODYNAMICS
consultation.
The primary aim of the chapter is to discuss the value
of the various tests to diagnose the mechanisms of
I. WHAT IS URODYNAMICS?
continence in general, to discuss what tests ought to
be performed to elucidate these mechanisms in the
individual; and to make recommendations for what The term ‘Urodynamic studies’ (UDS) was defined
tests should be performed for certain groups of by the International Continence Society (ICS) in 1988
patients. Thus we have tried to present an overview and involves the assessment of the function and
of the best scientific evidence with regard to the role dysfunction of the urinary tract by any appropriate
of urodynamics and lower gastrointestinal tract testing. method. [4] Amore recent report in 2002 did not alter
On the basis of this we provide recommendations for the definition of ‘urodynamic studies’or ‘urodynamics’
the current state of assessment of the patient with but did include a new definition of ‘urodynamic
incontinence, and recommendations for future scientific observations’. [5]
evaluation or analysis of dynamic testing. The overview
The conventional view – implicitly adopted in the
of scientific evidence in paragraphs, with conclu-
previous standardisations and consultations – is that
sion(s)and recommendation(s)and topics(s) for
urodynamics is a series of more or less agreed-upon
research are highlighted in the text and are therefore
clinical tests, such as flow studies, filling cystometry,
also suitable for ‘express reading’.
pressure-flow studies and/or urethral function
The third ICI report expressed the hope that faecal measurements. These can be combined with simult-
(anal) incontinence and urinary incontinence could aneous electromyography (EMG) recording and/or
417
imaging by either X-rays or ultrasound. Also implicitly f) to understand the reasons for failure of previous
agreed upon is that urodynamics is the only objective treatments for urinary incontinence, or for LUT
way to determine why people have lower urinary tract dysfunction in general.
symptoms (LUTS). The attempt to gain understanding
The International Continence Society has provided
of lower urinary tract (LUT) behaviour, on the basis
standards for urodynamic terminology and techniques
of test observations, in relation to what is known about
to optimise interpretation and facilitate comparison
normal – or expected abnormal- physiology, is what
between different studies [5]. Some of the urodynamic
constitutes urodynamics.
terminology is given in Table 1.
Urodynamic studies can answer questions such as:
Table 1. Some urodynamic diagnoses and corres-
‘What causes the increased voiding frequency in this
ponding urodynamic observations
patient’as well as: ‘Why does this patient have urinary
incontinence’? These questions not only can be posed Urodynamic diagnosis Urodynamic
for individual patients but also can form part of clinical observation
or laboratory research.
Urodynamic stress Loss of urine as result of
urinary incontinence an abdominal pressure
Conventionally, UDS involves the patient being
increase without detrusor
connected to equipment in the laboratory in order to
overactivity during the
measure physiological parameters, such as pressures,
storage phase of
inside the patient. The data is analysed as the test is
urodynamic testing.
being carried out and adjustments can be made to
correct for technical problems and artefacts as they Detrusor overactivity Loss of urine as a result
arise. If conventional urodynamic studies fail to provide incontinence of involuntary detrusor
an answer to the question being posed then activity during the storage
phase of urodynamic
ambulatory urodynamics may be employed in an
testing.
attempt to obtain the answer. [6] In ambulatory
urodynamics, pressures and other physiological Urodynamic mixed Occurrence of
parameters from the patient are fed into a small, body- urinary incontinence urodynamic stress
worn solid-state recorder and the patient is free to incontinence in
move about and carry out normal activities. The test combination with
can last for many hours and the physiological data is urodynamic urgency
analysed once the test has been completed. urinary incontinence or
detrusor overactivity.
Urodynamic urgency Detrusor overactivity
II. WHAT SHOULD BE THE ROLE OF
during urodynamic testing
URODYNAMIC STUDIES IN with urgency sensation
CLINICALPRACTICE? that the patient reports as
representative for his or
her symptoms.
There is an agreement among experts that the
immediate aim of urodynamic testing is to reproduce
the symptom(s) of the patient under controlled and
measurable conditions, so that the cause of the
symptoms can be determined and useful, objective
III. THE TESTS OF CONVENTIONAL
information can be provided to the clinician. The role
of urodynamic studies in broad clinical perspective URODYNAMICS
can be:
a) to identify or to rule out factors contributing to the 1. UROFLOWMETRY
LUTdysfunction (e.g. urinary incontinence) and
This is the non-invasive measurement of urine flow
assess their relative importance
rate. The patient micturates into a flow meter in private
b) to obtain information about other aspects of LUT when they have a normal desire to empty their bladder.
dysfunction [7] Urine flow rate is continuously measured and
displayed graphically. Various parameters from the
c) to predict the consequences of LUTdysfunction
trace are automatically calculated and printed out
for the upper urinary tract
together with the trace. The volume voided, shape of
d) to predict the outcome, including undesirable side
the curve and the maximum flow rate are usually the
effects, of a contemplated treatment
principal determinants of whether or not the patient
e) to confirm the effects of intervention or understand is emptying their bladder normally. If an abnormal
the mode of action of a particular type of treatment; recording is obtained, it is usual to repeat the
especially a new one assessment to check that the result is reproducible.
418
Several factors, such as patient apprehension, can give of the urethra and may be of help in determining the
an abnormal recording in patients who have no voiding management of the patient with USI.
difficulty. Repeating the assessment can eradicate
5. ABDOMINALLEAK POINT PRESSURE
the effect of such confounding factors and will confirm
or refute the validity of the first assessment. . This is a test carried out in some centres and is another
measure of the urethra’s ability to act as a valve to
2. FILLING CYSTOMETRY
contain urine within the bladder. Intravesical or
This is the measurement of the pressure inside the abdominal pressure is measured whilst the patient is
bladder to assess its storage capabilities. It is an asked to increase their abdominal pressure by valsalva
invasive test which involves a pressure sensor being or by coughing. The abdominal pressure required to
placed into the bladder, usually transurethrally, and produce leakage from the bladder gives an indication
another pressure sensor being placed rectally or of the closure function of the urethra. The greater the
vaginally (or sometimes through an abdominal stoma) pressure required to produce leakage, the better the
to measure abdominal pressure. Subtracting the closure function of the urethra. This test may be of help
abdominal pressure from the pressure measured in determining the management of the patient with
inside the bladder (intravesical pressure) gives a USI.
representation of pressure changes due to the action
of the detrusor smooth muscle.
IV. TECHNOLOGICALINNOVATIONS
During this assessment, the bladder is usually filled
with normal saline solution (or x-ray contrast solution IN URODYNAMICS
in the case of videourodynamics) either through a
separate catheter placed transurethrally or through the
1. AIR-CHARGED CATHETERS FOR PRESSURE
filling channel of a dual lumen catheter if such is used
MEASUREMENT
to measure intravesical pressure. Usually the filling rate
is much faster than physiological bladder filling.
Air-charged catheters have been used for pressure
measurement in urodynamics for many years.
The intravesical, abdominal and detrusor pressure
However, until recently, they have been the sole
are monitored as the bladder is filled and before the
preserve of enthusiasts who have manufactured and
patient has been given ‘permission to void’. The
used them ‘in-house’.
storage ability of the bladder is assessed in terms of
the volumes required to elicit various sensations from
Recently, commercial, single-use, air-charged
the patient, its capacity, its compliance and its stability.
catheters have been developed and used for
The filling (storage) phase of cystometry is also the
intravesical, intraurethral and abdominal pressure
only method of demonstrating urodynamic stress
measurement in urodynamics (T-Doc, Wenonah, NJ).
incontinence (USI).
Initial reports from a female cadaveric study showed
that these catheters gave more reproducible
3. PRESSURE-FLOW STUDIES (VOIDING
measurements of maximum urethral closure pressure
CYSTOMETRY)
compared to microtip catheters, water filled catheters
This is a measurement of the mechanics of micturition. and fibreoptic catheters. [8] In a more recent study in
When the filling (storage) phase of cystometry is 2004 on 45 women, their performance has been
complete, the patient is given ‘permission to void’and shown to be comparable to microtransducers in the
will empty their bladder on a flow meter whilst measurement of maximum urethral closures pressure
intravesical, abdominal and detrusor pressures are and Valsalva leak point pressure (VLPP). [9] However,
being monitored. The simultaneous measurement of the same study showed a difference in functional
flow rate and pressure enables voiding to be assessed urethral length (FUL) which was attributed to the
and, when bladder emptying is poor, it can help different diameters of the two catheters.
determine whether poor flow is due to an outflow
Acriticism of this study was that the catheters were
obstruction or poor detrusor contractility.
not used in a random order. Therefore in 2008,
4. URETHRALPRESSURE PROFILOMETRY Zehnder et al carried out a randomised comparison
of these catheters with microtip catheters in 64 women.
This is a test carried out in some centres and measures
The measured MUCP and FUL and found that the
the urethra’s ability to act as a valve to contain urine
air-charged catheter was as least as reliable as the
within the bladder. A pressure sensor is placed
microtip for measuring these parameters. However,
transurethrally into the bladder and then withdrawn
because the air-charged catheter gives a higher
along the urethra (usually by a mechanical puller at
reading of both parameters compared to the microtip
a constant rate). The pressure along the length of the
device, they concluded that they cannot be used
urethra is measured, usually relative to the pressure
interchangeably for clinical purposes. [10]
inside the bladder. The maximum pressure measured
in the urethra gives an indication of the closure function These devices are being actively marketed for the
419
measurement of intravesical and intraabdominal lines in the measurement of intravesical and intra-
pressure during filling and voiding cystometry. abdominal pressure during filling and voiding
However, there have been no published studies in cystometry; particularly during ‘fast’events such as
the peer-reviewed literature concerning their coughing.
performance in this way; there are only the studies
2.OBJECTIVE ASSESSMENT OF BLADDER
mention above which predominantly relate to the
SENSATION
measurement of urethral pressure. There is no reason
to suspect that these devices are inappropriate for
Bladder sensation during urodynamics is usually
the measurement of such pressures and, indeed, the
recorded by the simple expedient of asking the patient
measurement of VLPP by Pollak et al [9] is encou-
to inform the investigator when they experience
raging that they can be used to measure intravesical
different sensations. This is a somewhat subjective
pressure. Nevertheless, a comparison of the air-
measurement which can be confounded by the
charged catheters with the traditional fluid-filled lines
investigators inadvertently distracting the patient whilst
for intravesical and intra-abdominal pressure
bladder filling is being carried out. Investigators can
measurement would be useful; particularly comparing
also bias the measurement by inadvertent prompting
their measurements during relatively fast events such
of the patient.
as coughing.
In 2005, Craggs described a patient-activated, keypad
Air-charged catheters have several practical
‘urge score’ device to measure sensations during
advantages over fluid-filled pressure lines because
bladder filling. [11] This enables patient perceptions
there is no fluid connection between the patient and
of bladder filling and the successive stages of
the urodynamic equipment; just air. This means there
increasing bladder sensation to be recorded without
is no hydrostatic pressure effect to account for so that
prompting or intervention by the investigator. The
there is no need to position anything at the level of the
accuracy of the ‘urge keypad’ during filling
symphysis pubis. There is no need to flush the system
cystometrography was validated in patients with
through to exclude air; a process that is essential in
urgency incontinence, and compared with data
a fluid-filled pressure-sensing environment. There are
abstracted from patient voiding diaries. Craggs
no artefactual fluctuations in pressure produced when
concluded that the device provides reliable and
the patients move. Essentially, these devices are ‘plug
repeatable measures of different bladder sensations,
and play’which means they are much easier to set
with excellent, statistically significant consistency
up and use compared to the fluid-filled system.
between bladder volumes and corresponding levels
Therefore, they have the potential to overcome one
of the problem areas of urodynamics; that of setting of sensation.
up. However, although they may make urodynamics
The development of an objective method of recording
easier to set up, the conduct and interpretation of a
bladder sensation during filling cystometry appears to
urodynamic study still requires an experienced,
be desirable. Whether it improves the reproducibility
appropriately trained practitioner.
and sensitivity of urodynamics has yet to be
Conclusions (level 3) determined.
• Air-charged catheters may provide an acceptable 3. NON-INVASIVE PRESSURE-FLOW
alternative to other techniques for measuring the MEASUREMENTS
pressure closing the female urethra.
Over recent years, groups in Newcastle upon Tyne
• There have been no studies to show whether air- (UK) and Rotterdam (The Netherlands) having been
charged catheters provide an acceptable alternative developing non-invasive techniques to measure
to fluid-filled lines for measuring intravesical and pressure-flow in males.
intra-abdominal pressure in urodynamics.
The UK group has developed a penile cuff device.
Recommendation (grade C) [12] The cuff is placed around the penis and is inflated
and deflated whilst the patient voids into a urine flow
• Investigators planning to use air-charged meter. The pressure required to interrupt the flow is
catheters for intravesical and intra-abdominal assumed to be equivalent to the bladder pressure
pressure in urodynamics would be advised to generating the flow at that time. The group has
check for themselves that they have an determined that cuff widths of 40 to 50 mm are optimal
equivalent performance to their current system for ensuring good pressure transmission from the cuff
for measuring pressure to the urethra. [13]
Further development of the technique resulted in the
Topic for research
publication of a nomogram to classify whether
• That a study is set up to compare the performance individuals are obstructed or not obstructed when
of air-charged catheters with fluid-filled pressure measured by this technique. [14]
420
There is apparently good agreement between patients enrolled in a study of changes in urinary
experienced operators regarding the measurement of bladder contractility secondary to benign prostatic
the pressure at which flow is interrupted. [15] In 2008, hyperplasia. [21] In 618 (94%) of 659 eligible
non-invasive measurements of pressure and flow participants, one condom pressure measurement was
were carried out at six different sites in the UK. [16] completed; two measurements were done in 555
The measurements on individuals were repeated a (84%). The maximum condom pressure ranged from
median of 20 days later. Only 69% of tests produced 28 to 228 cm H2O (mean 101, SD 34). Adifference
analysable data on the two occasions. Whilst the between the two pressures of less than ±21 cm H2O
mean differences in flow rate (0.2 ml/s) and cuff was found in 80%. The mean difference was -1 cm
interruption pressure (4 cm H2O) were small, 33% of H2O (SD 18), significantly different from 0.
men changed diagnostic category with the repeat
In the same year, the repeatability of the condom
measurement (from obstructed to non-obstructed or
catheter technique was assessed in 457 volunteers
vice versa).
and compared to that of the invasive pressure-flow
There is evidence that the method is sensitive to technique in 397 comparable male patients. [22] The
change. In 2007, 163 men underwent non-invasive repeatability of the non-invasive method was found to
pressure flow study using the penile cuff technique be comparable to, or slightly better than, that of
before and 4 months after transurethral prostate pressure-flow studies.
resection. [17] There was a significant change in flow In 2006, the bladder volume dependency of the
rate and cuff-interruption pressure following removal isovolumetric intravesical pressure measurement by
of the obstruction in addition to 80% becoming non- the condom catheter technique was investigated. [23]
obstructed on the basis of their measurements.
In the 1,020 healthy subjects studied, it was concluded
The same group produced retrospective evidence that the optimum bladder volume for isovolumetric
that categorisation of bladder outlet obstruction by pressure measurements, was 264 ± 122 mL(mean
the penile cuff technique improves prediction of ± SD) and that measurements should be taken at or
outcome from endoscopic prostatectomy. [18] In 179 above this optimum volume. At volumes below the
men undergoing TURPfollowing standard assessment optimum volume, the pressure decreases by
in the institution concerned, 37% were catergorised approximately 5% for each 10% of volume decrease.
as having bladder outlet obstruction (BOO) by the At bladder volumes smaller than 247 mL, pressure
penile cuff test and 87% of these had a good outcome readings in 50% of subjects were suboptimal.
from TURP. Whereas of the 19% the of deemed not
The same group in Rotterdam has also been exploring
obstructed, 56% experienced a good outcome
the measurement of perineal noise during voiding as
(p<0.01). In the remaining men not categorised in
a way of non-invasively quantifying male bladder
these two groups, 77% had a good outcome. However,
outlet obstruction but the work has not yet progressed
the retrospective nature of this study weakens the
sufficiently beyond testing on models to determine
argument for the prognostic ability of the penile cuff
the viability of this technique in vivo. [24, 25]
test.
Both the penile cuff and condom catheter techniques
The penile cuff test is now commercially available as
show promise as non-invasive techniques to assess
the CT3000 (Mediplus Ltd, High Wycombe, UK)
outlet obstruction in men. However, they are subject
The group in Rotterdam had a similar approach to to some confounding factors and appear to give
developing a non-invasive method of measuring inaccurate results if the patient strains during the
pressure and flow in men. However, instead of using assessment. It remains to be seen where and if these
a penile cuff to interrupt flow, they used a condom
measurements have a role in the routine clinical
catheter through which the patient voided into a urine
assessment of men with symptoms of bladder outlet
flow meter. During flow, the stream would episodically
obstruction.
be diverted to a pressure transducer which would
record the bladder pressure at that time. [19] They were Conclusion (level 2)
able to correctly classify most men as being obstructed
• Non-invasive measurements of pressure and flow
or not obstructed when compared to the ICS
in men by the penile cuff or condom catheter seem
nomogram provided that the men did not strain during
to be as clinically useful as the traditional invasive
voiding.
measurement of pressure and flow.
Further work on the technique in 2003 revealed that
a minimum flow rate of 5.4 ml/s was necessary to Recommendation (grade B)
produce an accurate assessment of bladder pressure
during voiding using the condom catheter technique. • That non-invasive measurements of pressure
[20] and flow should be considered when the patient
is not required to undergo an invasive
In 2004, the technique was reported to have a
assessment of the storage function of the lower
reproducibility comparable to that of invasive pressure-
urinary tract.
flow studies in an interim analyis of the first 730
421
4. URETHRALRETRO-RESISTANCE In 2007, Tunn et al measured URPin 48 women with
PRESSURE clinically and urodynamically proven SUI without
prolapse before and after anti-incontinence surgery
In 2004, Slack et al described a ‘new clinical measure
(colposuspension n = 8, tension-free vaginal tape n
of urethral function’. [26, 27] In the measurement of
= 6, tension-free transobturator tape n = 34). They
urethral retro-resistance pressure (URP), a small
found that preoperative URP did not correlate with
meatal plug is inserted just inside the female urethra
SUI in all women, had no predictive value, and did not
and saline is pumped into the urethra. The pressure
correlate with the outcome of anti-incontinence surgery.
in the system rises until it reaches a value sufficient
However, they did find a positive correlation between
to overcome the resistance offered by the urethra
URPand body mass index. [30]
and the fluid then retrogradely flows into the bladder.
The pressure required to achieve and maintain an In 2008, Roderick et al reported on URP and
open sphincter is taken to be a measure of urethral established measures of incontinence severity in 100
closure function. Whilst the technique is new in that women with pure USI prior to and 3 months after the
modern technology is used to apply the head of insertion of a midurethral tape. [31] They found mean
pressure to the urethra and the measurement of URPbore no relationship to the severity of urine loss
opening pressure is automatically recorded, the basic assessed by 24-hour pad loss. There was no
principle behind the technique has its origins in 1923 correlation between URP and other measures of
when Bonney made a simple attempt to measure the incontinence severity. Pre and postoperative URP
efficiency of urethral closure. [28] was available in 73 women. Although 84.9% were
objectively cured after surgery, pre and postoperative
In his first paper, Slack et al studied 258 stress
URP was not significantly different (62.7 ± 19.4 cm
incontinent women with the URP technique and
H2O vs 61.2 ± 20.4 cmH2O). They concluded that
compared their values with incontinence severity.
urethral retro-resistance pressure is not a useful
They also compared the URP measurements with
measure of urethral function.
those of maximum urethral closure pressure (MUCP)
and valsalva leak point pressure (VLPP). They found Conclusion (level 2/3)
that URP measurements correlated well with both
• Urethral retro-resistance pressure measurements
MUCP and VLPP. They also found that URP
do not give any better information about urethral
measurements correlated with incontinence severity
closure function than the urethral pressure profile
whereas neither MUCPnor VLPPdid so. [26]
or valsalva leak point pressure.
In the second study, Slack et al showed that the URP
Recommendation (grade B/C)
in a group of 61 women, without symptoms of urinary
incontinence and who had negative standing stress
tests, was significantly greater than the group of stress
• That urethral retro-resistance pressure
incontinent women who had been tested previously.
measurements should be discouraged because
[27] This study also provided some test-retest data
equivalent information can be obtained from
which showed that URP measurements were
urethral pressure measurements made with
consistent in individuals.
conventional urodynamic equipment.
The authors concluded from both of these pieces of
work that the technique of URPshows promise as a
5. URETHRALPRESSURE REFLECTOMETRY
physiological urethral pressure measurement.
In 2005, Klarskov et al reported on an in vitro study
In 2006, Digesu et al carried out measurements of URP
of pressure reflectometry; a novel technique for the
on 165 women with various urodynamic diagnoses.
simultaneous measurement of cross-sectional area
[29] Women with urodynamic stress urinary
and pressure in a collapsible biological tube. [32] A
incontinence (USI) had significantly lower URPthan
very thin, highly flexible 6 cm long polyurethane bag
women with competent urethral sphincters. Women
with a diameter of 5 mm when expanded was
with mixed urodynamic incontinence had values of
introduced into eight different test model cavities of
URP intermediate between women with detrusor
known cross-sectional areas in the range of 4-16
overactivity (DO) and those with USI. In the mixed
mm2. The cross-sectional area was measured by
group, URPmean values were not significantly different
acoustic reflectometry while pressures of 10-200 cm
from those with DO and competent sphincters or those
H2O were applied by a pump. Measurements were
with USI.
reliable from about 1 to 5 cm within the cavity and at
There was no significant difference between mean pressures from 10 to 200 cm H2O. The reproducibility
URP values and different urinary symptoms. The was not influenced significantly by change in
authors concluded that whilst there are significantly background noise, temperature, catheters, or
different URPmeasurements between women with DO geometries of the cavities or new calibration. They
and those with USI, the URPis not a diagnostic tool. concluded that the measurements seem reliable for
422