URODYNAMIC EVALUATION

Latha .G
Urodynamic Evaluation of
Voiding Dysfunction
Dept of Urology
Govt Royapettah Hospital and Kilpauk Medical College
Chennai

Moderators:
Professors:
 Prof. Dr. G. Sivasankar, M.S., M.Ch.,
 Prof. Dr. A. Senthilvel, M.S., M.Ch.,
Asst Professors:
 Dr. J. Sivabalan, M.S., M.Ch.,
 Dr. R. Bhargavi, M.S., M.Ch.,
 Dr. S. Raju, M.S., M.Ch.,
 Dr. K. Muthurathinam, M.S., M.Ch.,
 Dr. D. Tamilselvan, M.S., M.Ch.,
 Dr. K. Senthilkumar, M.S., M.Ch.
Dept of Urology, GRH and KMC, Chennai. 2

History
 Urodynamics was first defined by David M. Davis in 1953
The study of the storage and emptying phases of the
urinary bladder ( Davis, 1953 ).
 The cystometrograph, introduced in 1927 by D. K. Rose, was one
of the earliest urodynamic instruments for measuring bladder
pressure during filling and voiding ( Rose, 1927 ).
 This was followed by the uroflowmeter by Drake in 1948 .
 In the 1950s, the development of simultaneous radiographic
imaging done in conjunction with physiologic studies was
pioneered by Hinman and Miller ( Hinman et al, 1954 ).
3
Dept of Urology, GRH and KMC, Chennai.

 Today, the urodynamic armamentarium is
 uroflowmetry and

 cystometry as well as
 pressure-flow studies,
 electrophysiologic studies,
 urethral pressure studies, and
 videourodynamic studies.
4

 Nitti noted three important principles in
urodynamics:
 (1) a study that does not duplicate the patient's
symptoms is not diagnostic,
 (2) failure to record an abnormality does not rule
out its existence, and
 (3) not all abnormalities detected are clinically
significant ( Nitti and Combs, 1998 ).
5

Aim of urodynamics
 The aim of clinical urodynamics is to
reproduce symptoms while making precise
measurements of the bladder physiology.
6

 Indications and Selection of Patients for Conduction of
Urodynamics
I. Patients in whom potential therapy may be hazardous where one
would want to be sure of the correct diagnosis before instituting
therapy
II. Patients with recurrent incontinence in whom surgery is planned
III. Patients with incontinence and a confusing mix of stress and urge
symptoms and those with associated voiding problems
IV. Patients with neurologic disorders and those with a mismatch
between symptoms and clinical findings
Patients with LUTS suggestive of bladder outlet obstruction
7

V. Patients with LUTS who have both obstructive and marked
instability symptoms
VI. Patients with obstructive LUTS and neurologic disease
Young men with LUTS
VII. All neurologically impaired patients who have neurogenic
bladder dysfunction
VIII. Children with daytime urgency and urge incontinence
IX. Children with persistent diurnal enuresis
X. Children with spinal dysraphism
8

PREPARATION OF PATIENTS AND
PRECAUTIONS
 prestudy discussion of the study technique and
counseling about the risks are appropriate
 During the study, the patient should understand what
information we are trying to collect sufficiently to be
able to volunteer timely responses to changing events.
 Some may have been started empirically on medication
for their symptoms including anticholinergics, α
blockers, bladder relaxation medications, and
psychotropic medications. These affect urodynamic
outcomes and should be stopped with an adequate
washout period prior to the test.
9

 An adequate history and physical examination
should be performed before the test and
 a voiding diary completed to determine the
functional capacity, daily urine output, and
approximate filling volume
10

Antibiotics
 Pretest urinalysis is negative for infection
 Parenteral antibiotic prophylaxis may be necessary in
specific patients, such as those with cardiac valve
abnormalities, orthopedic prostheses, genitourinary
prostheses, pacemakers, and other electrical devices
 patients with total joint replacements within 2 years
after implant surgery, immunocompromised patients,
and those with previous prosthetic joint infections (
American Urological Association Advisory Statement,
2002 ).
11

The Urodynamics Room
 The room used for urodynamics should be without
distractions, quiet, and protected from unnecessary
interruptions.
 The room should be large enough for the physician
 to perform a physical and pelvic examination,
 to place catheters, and
 to move unencumbered within the room.
 One should always take into account the need for
sufficient room to allow for wheelchairs and assist
devices such as walkers.
12

URODYNAMIC EQUIPMENT
 Three measurement
channels,
 two for pressure and
 one for flow;
 a display (on either a
printer or a monitor); and
 a method for secure
storage of the recorded
pressures (abdominal,
vesicle, detrusor) and
 flow measurements as
tracings against time (
Schafer et al, 2002 ).
13

 The infused volume and voided volume may be recorded
graphically or numerically.
 all measured and derived signals must be displayed
continuously over time according to ICS standards,
preferably with the following sequential position of
tracings:
 from top down on the page
 Pabd (abdominal pressure),
 Pves (vesical pressure),
 Pdet (detrusor pressure), and
 flow (Q).
 Filling volume,
 electromyography (EMG), and
 voided volumes may be displayed.
14

Catheters
 The standard catheter for routine urodynamics is a
transurethral, double-lumen catheter .
 Suprapubic placement has been used in patients with
obstruction such as urethral stricture disease,
 The smallest available is the 6 Fr double-lumen
catheter.
 This allows the fill and void sequence to be repeated
without recatheterization.
 similarly sized triple-lumen catheters are available
that allow bladder filling, intravesical pressure
measurement, and urethral pressure recording.
15

 The use of a balloon catheter is best for the
measurement of abdominal pressure.
 An air-free balloon in the rectum or in the vagina
in women.
 The balloon maintains a small fluid volume at the
catheter opening to avoid fecal blockage
preventing pressure transmission.
16

Flowmeters
 The flow rate is measured by a uroflowmeter with the
SI unit for flow being cubic meters per second
(m3/sec) and for mass flow rate kilograms per second
(kg/sec)
 Most flow rates are reported in milliliters per second
(mL/sec) .
 Most flowmeters are calibrated for water, which has a
density of 1; therefore, the mass of the fluid in grams
equals the volume in milliliters.
17

Urodynamics Equations
 1. Flow rate:
Flow is the change in volume over the change in time: q = dV/dt:
flow rate (Q), volume (V), time (T),
 2. Compliance:
C (compliance) = dV/dPdet (detrusor pressure).
 3. Detrusor pressure:
pdet = pves - pabd,
pdet (detrusor pressure), pves (vesical pressure), pabd (abdominal
pressure).
 4. Physiologic filling rate for cystometry:
rate = body weight (in kg)/4, expressed as mL/min.
18

Types of Flowmeter
 Gravimetric flowmeters operate by measuring the weight of the
collected fluid or by measuring the hydrostatic pressure at the
base of the collecting cylinder.
 The electronic dip stick flowmeter measures the electrical
capacitance of a dipstick mounted in a collecting chamber.
 In the rotating disk flowmeter the voided fluid is directed onto a
rotating disk. The power required to keep the disk rotating at a
constant rate is measured and proportional to the mass flow rate
of the fluid.
 Today, most available flowmeters are gravimetric or rotating disk
transducers. 19

Electromyography Equipment
 EMG is the study of the electrical potentials produced
by the depolarization of muscle membranes.
 The depolarization must first be detected by an
electrode placed close to the origin of the signal.
 These include intramuscular needle electrodes and
surface electrodes placed on the skin or mucosa
overlying the muscle of interest.
20

Types of Electrodes
 Self-adhesive, skin patch electrodes provide good surface recordings and
allow patients mobility. These electrodes are predominantly used in
pediatric urodynamics.
 Needle electrodes provide better recording quality and specificity for
certain muscle groups.
 Wire electrodes are made of stainless steel, platinum, or copper wire. The
wire is placed into the muscle to be studied through a needle acting as a
cannula.

 Monopolar electrodes are thin needles coated with an insulating
material with an exposed tip. They need a reference electrode, a small
metal disk attached to the skin near the muscle being examined.
 Concentric electrodes consist of a wire inside an outercannula,
separated by insulating material. The outer, conductive portion serves as
the ground. This can record from one to three motor units
simultaneously.
21

CONDUCTING THE URODYNAMIC
EVALUATION
22

Uroflow
 Uroflowmetry is noninvasive, inexpensive, and
invaluable in screening patients with voiding
dysfunction.
 This noninvasive test should precede any other
urodynamic studies.
 It is easy to perform and quickly provides data on both
storage and voiding symptoms.
 Ideally, two or more tests should be performed, and
the addition of a noninvasive postvoid residual volume
measurement by ultrasound adds to the value of the
study.
23

 Normal voiding includes
 a detrusor muscle contraction,
 coordinated bladder outlet relaxation,
 low voiding pressure, and
 a smooth, arc-shaped flow curve ( Schafer et al,
2002 ).
 The flow pattern-the shape of the flow tracing,
sometimes be used to make a presumptive
diagnosis.
24

 The normal flow
pattern is a
continuous, bell-
shaped, smooth curve
with a rapidly
increasing flow rate

25

 The typical obstructed flow pattern has a plateau-
shaped curve with a prolonged flow time,
sustained low flow rate, and increased time to
Qmax.
 An intermittent flow pattern is one that has one
or several episodes of flow increasing or
decreasing (or ceasing completely) and is
commonly secondary to abdominal straining or
external sphincter spasm (e.g., detrusor-sphincter
dyssynergia).
26

 Data from the uroflow curve include
 maximum flow rate,
 total voided volume,
 average flow rate, and
 the postvoid residual.
 The curve shape and Qmax is volume dependent, only
voided volumes of at least 150 mL should be
interpreted .
 The maximum flow rate should always be
documented together with the total voided volume
and postvoid residual volume.
27

Uroflow in Men.
 Normal uroflow parameters in young men are
well established.
 Qmax greater than 15 to 20 mL/sec as normal and
 less than 10 mL/sec abnormal.
 Decline with age by 1 to 2 mL/sec per 5 years.
 A maximum flow of 5.5 mL/sec at 80 years
28

Uroflow in Women.
 Women have
 a very short urethra,
 minimal outlet resistance, and
 no prostate,
 only factors influencing female uroflow are
the strength of the detrusor muscle and
the urethral resistance and
the degree of relaxation of the sphincter mechanism.
 In the normal woman Qmax can be greater than 30 mL/sec,
 the flow curve is bell shaped as in men, and
 the flow time is shorter
 Maximum flow in women does not seem to be dependent
upon age.
29

The Cystometrogram
 Cystometry –
 The urodynamic investigation of the filling
component of bladder function.
30

The Procedure
 Measurement of Intravesical and Abdominal
Pressure.
 Zero pressure is the surrounding atmospheric
pressure.
 the reference point is the superior edge of the pubic
symphysis
 All systems must be zeroed to atmospheric pressure,
and it is crucial that there are no air bubbles in any of
the transducers or tubing as these may cause pressure
dampening or dissipation.
31

Fill Medium
 A physiologic liquid medium is preferable.
 Fluid cystometry uses more physiologic media such as
sterile water, normal saline, or contrast material.
 These are not compressible and allow better
assessment of voiding dynamics.
 Liquids allow easier detection of incontinence and are
more physiologic.
 Other advantages
 the ability to determine fluid loss and leak pressures
and
 to serve as a medium for fluoroscopy.
32

 The physical characteristics of the infused liquid
may affect bladder behavior and urodynamic
measurements. Acidic and alkaline solutions may
increase or decrease overactivity in otherwise
normal bladders.
 Temperature is also important. eg. Iced water may
provoke overactivity,
33

FILL RATE
 Slow (“physiologic”) fill—less than 10 mL/min
 Medium fill—10 to 100 mL/min
 Rapid fill—more than 100 mL/min
 Filling is most often performed at a medium fill
rate with the slow rates reserved for second fills in
patients who demonstrate significant detrusor
overactivity at a faster fill rate.
 Provocative filling using the faster rates may be
used to expose bladder overactivity in patients
with a complaint of urgency.
 34

 Prior to filling, we prefer to conduct a noninvasive
uroflow test as described earlier.
 The patient is then catheterized for a postvoid
residual at the time of cystometry catheter
placement.
 During cystometry, periodic coughing should be
elicited to ensure accurate pressure recording in
all channels being monitored (Pdet as derived
from Pves and Pabd).
35

 A few common errors that result in inability to
obtain a correct zero include
 pressure line displacement,
 kinking of the tubing,
 compression of the lumen of the tubing against
the bladder or rectal wall, and
 the presence of air bubbles.
36

Filling cystometry
 During the course of cystometry,
 Four bladder characteristics;
 capacity, sensation, compliance, and the
occurrence of involuntary contractions.
37

 The typical cystometrogram
(CMG)
 (I) The immediate rise to
resting bladder pressure -the
response of the viscoelastic
properties to the stretch of
filling.
 (II) The tonus limb-the
viscoelastic properties of the
bladder wall.
 (III) The point at which bladder
wall structures have achieved
maximal elongation and a
pressure rise is caused by
additional filling (i.e., exceeding
the limit of compliance).
 (IV) The voiding phase
consisting of a voluntary
bladder contraction
38

 The CMG in two components:
 the response to filling
 when capacity has been achieved,
 the period of storage testing when there is no further
fill
 patient stresses the full system with provocative
maneuvers such as
cough,
Valsalva maneuver, and
other provocative activities.
 supraphysiologic filling rates
39

Capacity
 Maximum cystometric capacity
bladder volume at the end of the filling CMG when
patients have a strong desire to void, feel they can no longer
delay micturition, and are given permission to void . This
volume includes 1.the amount voided and 2.the residual
urine left after the void (postvoid residual).
 The functional bladder capacity is the largest volume voided
as determined by a voiding diary.
 The cystometric capacity is usually slightly greater than
functional bladder capacity
 The maximal anesthetic capacity is the volume of the
bladder after filling under anesthesia (general, spinal,
epidural) and is not routinely measured.
40

Sensation
 Bladder sensation is evaluated by questioning the
patient about the feeling of the degree of bladder
fullness and is the point at which cooperation
between the patient and examiner becomes very
important.
 Normal bladder sensation -
 the first sensation of bladder filling,
 the first desire to void, and
 a strong desire to void .
 Urgency,
 pain, and
 multiple other sensations should be documented
during filling as well .
41

Compliance
 Bladder compliance is the relationship between
change in volume and change in pressure.
 It is generally calculated between two points:
 the Pdet with the bladder empty at the start of
filling and
 the Pdet at either the maximal cystometric
capacity or the start of a detrusor contraction.
 Normal bladder compliance should be less than
12.5 mL/cm H2O .
42

43

Storage
 Normally, bladder filling
occurs with little or no
change in pressure, and
 a “stable” bladder is a
reflection of the
integrity of the central
nervous system control
over bladder function.
 There should be no
involuntary contractions
during filling
cystometry .
44

Detrusor overactivity
Multichannel filling cystometrogram shows detrusor
overactivity with multiple contractions
45

Cystometry summary
 the normal bladder capacity is in the range of 300
to 500 mL;
 the bladder should have a constant, low pressure
that usually does not reach more than 6 to 10 cm
H2O above baseline at the end of filling (end-
filling pressure); and
 there should be no involuntary contractions.
46

Pitfalls in Cystometry
 i. pressure measurement artifacts (the presence of air bubbles,
kinked tubing, incorrect placement, migration of the pressure
catheters) and
 ii. infusion rate artifacts (especially in neurogenic bladder) and
 iii. patient-related issues, including lack of cooperation, outlet
incompetence, and vesicoureteral reflux.
 iv. If bladder filling is too rapid,
 v. If the bladder outlet is incompetent, urine may leak around the
filling catheter and a low bladder compliance may not be
diagnosed because the bladder is never adequately filled (e.g.,
spinal dysraphism, severe intrinsic sphincter deficiency [ISD] in
an older woman).
47

Special Testing
Bethanechol supersensitivity test
 The bethanechol supersensitivity test was described by
Lapides and modified by Glahn (1970) .
 This test involves standard fluid infusion cystometry at a
filling rate of 1 mL/sec until a bladder volume of 100 mL is
achieved.
 Bladder pressures are recorded, and

 this is repeated two to three times for an average value.
 Bethanechol chloride (0.035 mg/kg) then is administered
subcutaneously.
 Cystometry is repeated at 10, 20, and 30 minutes after
injection. 48

 A neurologically intact bladder should have a
pressure increase of less than 15 cm H2O above the
control value
 a “denervated” bladder shows a response greater
than 15 cm H2O.
 A positive test suggests an interruption in the
afferent or efferent peripheral, or distal spinal
innervation, of the bladder.
49

Ice water test
 The ice water test was first described by Bors and
Blinn as a way to differentiate “upper” from
“lower” motor neuron lesions .
 It is based on the principle that mucosal
temperature receptors can elicit a spinal reflex
contraction of the detrusor, a reflex that is
normally inhibited by supraspinal centers.
50

 An upper motor neuron lesion interrupts these
inhibitory pathways, resulting in manifestation of
the reflex
 A lower motor neuron lesion does not.
 A positive test should therefore theoretically
occur in patients with upper motor neuron
lesions, whereas those with lower motor neuron
lesions and neurologically normal patients
should have a negative test.
51

 The original test involved rapidly injecting the
bladder with ice water;
 if the ice water is expelled by the bladder within 1
minute, the test is positive.
 The test is positive in approximately 97% of
patients with complete suprasacral lesions and in
91% of those with incomplete suprasacral lesions;
it is almost never positive in patients with lower
motor neuron lesions.
52

Pressure-Flow Studies
 Pressure-flow studies (PFSs) measure the relationship between
pressure in the bladder and urine flow rate during bladder emptying .
 Indications :
❖ to differentiate between patients with low flow because of
obstruction and those with poor bladder contractility.
❖identify patients with high-pressure obstruction and normal flow
rates .
❖Obstruction
❖1. structural caused by prostatic enlargement and stricture, 2.
functional, caused by proximal or distal sphincter dyssynergia.
❖PFSs alone cannot identify the location of the obstruction, but when
combined with fluoroscopic screening or a sphincter EMG study, the
site of obstruction may be determined.
53

 PFSs are especially useful in the evaluation of men with LUTS
 A low flow rate is not diagnostic of BOO because 25% to 30% of
patients with low flow rates have detrusor hypocontractility
 A normal or high flow rate does not rule out obstruction because 7%
of symptomatic men with a Qmax greater than 15 mL/sec have
obstruction
 PFSs should be performed when the information obtained will
influence major therapeutic decisions.
 Older men with LUTS and any H/O neurologic disease such as CVA,
multiple sclerosis, or Parkinson's disease, which are known to affect
detrusor or sphincter function.
 Younger men with LUTS benefit from PFSs to determine whether a
functional disorder (e.g., bladder neck dysfunction) is present.
 PFSs are also helpful in men with BPH and Qmax over 10 mL/sec, a
group making up 30% to 40% of BPH patients.
54

 The normal male generally voids with a Pdet of 40
to 60 cm H2O, and women typically void with
lower pressures .
 Obstruction existed in a patient with a Pdet of 100
cm H2O at a Qmax of 10 mL/sec.
55

 women with LUTS, depending on the definition,
obstruction was identified in 2.7% to 20% of cases
 PFSs may be misleading in women with suspected
obstruction.
56

Female Bladder Outlet Obstruction
 Female bladder outlet obstruction is being recognized
more frequently, but standardized urodynamic
criteria for its diagnosis have been lacking.
 Blaivas and Groutz (2000) have developed a
nomogram for the obstructed woman.
 urodynamic values of maximum flow (Qmax) and
 detrusor pressure at maximum flow (Pdet.max),
 this nomogram defines obstruction in women as four
types:
 no obstruction,
 mild obstruction,
 moderate obstruction, and
 severe obstruction.
57

Abrams-Griffiths Nomogram.
 The Abrams-Griffiths (AG) nomogram was based
on “theoretical analysis and empirical
observation” in symptomatic men undergoing
PFSs .
 Categorized as
 Obstructed- > 40 cm H2O
 Equivocal- 20-40 cm H2O
 Unobstructed- < 20 cm H2O.
 AG nomogram is calculated from the formula
 AG number = PdetQmax - 2Qmax .
58

 for determining urethral resistance is based on
consideration of the urethra as a distensible tube with a
flow-controlling zone, the proximal urethra.
 It describes the relationship between pressure and flow
during the period of lowest urethral resistance and
 reflects the passive anatomic factors responsible for the
outlet resistance or flow-controlling zone and minimizes
the effect of muscular activity, such as sphincter contraction.
Schafer's method
59

Group-Specific Urethral Resistance
Factor nomogram.
 The URA was derived from the recognition of a
correlation between the minimal opening pressure
(Pmuo) and the curvature of the PURR, resulting in
the ability to use one parameter, the URA, to define
obstruction.
 A nomogram was created with a series of parabolic
curves showing the average pressure-flow plots for
different values of Pmuo.
 By plotting the PdetQmax*Qmax point from a
patient's PFSs onto the nomogram, a corresponding
URA number is obtained.
 A URA greater than 29 cm H2O is considered to
represent obstruction.
60

The ICS Provisional Nomogram
 It is very similar to the AG nomogram except that the
boundary between unobstructed and equivocal has
been moved to reduce the size of the equivocal region.
 A continuous grading of obstruction is possible by
calculating the bladder outlet obstruction index
(BOOI), which is essentially the AG number, given by
the formula
 BOOI = PdetQmax - 2(Qmax).
 The patient is considered
 obstructed if the BOOI is greater than 40,
 unobstructed if the BOOI is less than 20, and
 equivocal if the BOOI is between 20 and 40.
61

ICS Provisional Nomogram
62

 An index of bladder contractility (bladder
contractility index [BCI]) can be factored
PdetQmax + 5Qmax.
 Using this formula for the BCI (i.e., BCI =
PdetQmax + 5Qmax),
 BCI greater than 150 is strong,
 BCI less than 100 is weak, and
 BCI of 100 to 150 is normal
contractility .
63

If this is plotted graphically on a nomogram,
patients can be categorized into nine classes,
according to three obstruction and three
contractility categories
64

Videourodynamics
 Def : The simultaneous display of bladder and
urethral pressures with fluoroscopic imaging of the
lower tract is videourodynamics.
 It is the most sophisticated form of evaluation of
patients with complex urinary tract dysfunction.
 This is desirable when simultaneous evaluation of
structure and function is necessary to make a
diagnosis .
 Videourodynamics is useful to identify the specific
site of the obstruction as being at the bladder neck,
the prostatic urethra, or the distal sphincter
mechanism .
65

66

 A videourodynamic evaluation is indicated when a
diagnosis cannot be made with certainty without
simultaneous evaluation of the structure and
function of the urinary tract ( McGuire et al, 1996a ).
 Anatomic abnormalities that can also be identified or
evaluated with videourodynamics include cystocele,
diverticulum of the bladder or urethra, and
abnormalities of the prostatic and proximal urethra,
and it may also give information on the pelvic support
and pelvic organ prolapse.
 Significant pelvic organ prolapse may cause changes
in the urodynamic parameters measured, and the
significance of this cause may go unrecognized unless
fluoroscopy is added.
67

 Videourodynamic studies can be performed
 fluoroscopic units,
 a fluoroscopy table, and
 a radiographic contrast agent as the filling medium.
 A tilting fluoroscopy table is necessary as it allows supine
placement of catheters with easy conversion to a sitting or
standing position to conduct the study.
 A commode seat attached to the table facilitates
fluoroscopic screening of voiding in the seated position,
which is ideal for women.
 An alternative system, used currently by these authors, uses
a fluoroscopic C-arm and a purpose-made tilting chair
system . 68

 The basic video and urodynamic setup that allows both
urodynamic and radiologic imaging data to be projected
simultaneously onto a television monitor for real-time
viewing and for digital storage for later review.
 Fluoroscopy time is limited by screening only points of
interest (Valsalva and cough events during fill and sections
of the voiding study) and should be less than 1 minute.
 Many manufacturers make urodynamic equipment
integrating the video and pressure flow data.
 The most important feature is the capability to measure
urethral and bladder pressures while displaying them
simultaneously with the corresponding fluoroscopic
images ( McGuire et al, 1996a ).
69

Using this technique, the examiner is able to gain information on many
aspects of the bladder and bladder function.
Vesicoureteral reflux and the status of the bladder neck and sphincter may
be identified.
The anatomy of the bladder, including diverticula, shape, and bladder
neck, may be determined as well.
Also, it allows identification of dyssynergia of the proximal and distal
sphincter mechanisms in neurogenic patients.
70

Particular Uses for Videourodynamics
 1. Evaluation of Incontinence.
 Identify the presence and degree of urethral
hypermobility, bladder neck competence, and the
presence and grade of cystocele.
 Video also improves the accuracy of a Valsalva
leak point pressure (VLPP) measurement, making
it is easier to observe the exact moment when
leakage of contrast agent
71

 2. Bladder neck dysfunction
incomplete opening of the bladder neck during
urination. This was first fully described by Turner-
Warwick in 1973, most common in young men who
complain of long-standing LUTS ( Webster et al, 1980 ).
Urodynamics alone can easily show evidence of bladder
outlet obstruction.
The diagnosis of this disorder must be made with real-
time, fluoroscopic imaging of the micturition event
showing detrusor contraction in the absence of bladder
neck relaxation.
72

3.Neurogenic Bladder Dysfunction.
 For neurogenic detrusor overactivity,
simultaneous video screening detects the
presence of leakage per urethra or vesicoureteral
reflux
 Aids in the determination of diagnosing proximal
and distal sphincter dyssynergia.
73

Identification of Associated
Pathology.
 Videourodynamics allows the identification and
characterization of a pathologic process that can
be associated with complex voiding dysfunction,
including reflux, diverticula, fistulas, and stones.
74

Multichannel Urodynamics
 The use of multichannel urodynamics,
incorporating these components into one all-
inclusive study.
 Multichannel urodynamics use simultaneous
recording of total bladder pressure (Pves) and
separate abdominal pressure (Pabd).
 Detrusor pressure (Pdet) is the component of
intravesical pressure (Pves) created by both active
(bladder contractions) and passive (elasticity)
forces from the bladder wall .
75

 The detrusor pressure (Pdet) is derived by
subtracting the Pabd from Pves.
 Pabd is most often recorded by a catheter placed
in the rectum.
76

 The pressure transducers for the bladder and rectal
catheters must be at the same reference level (at the
upper edge of the pubic symphysis), and
 the rectal catheter should be zeroed to equal bladder
pressure (which is zeroed to atmospheric pressure) at
the start of the study.
 The lines should be flushed and the adequacy of
pressure transmission checked by having the patient
cough to demonstrate a rise in rectal pressure (Pabd),
a rise in vesical pressure (Pves), and essentially no
change in the subtracted detrusor pressure (Pdet).
77

Leak Point Pressures
 Two pressures obtained during urodynamics
measure different aspects of lower urinary tract
function, detrusor leak point pressure (DLPP)
and abdominal leak point pressure (ALPP).
 DLLP is defined by the ICS as the lowest detrusor
pressure at which urine leakage occurs in the
absence of either a detrusor contraction or
increased abdominal pressure.
 ALPP is the intravesical pressure at which urine
leakage occurs because of increased abdominal
pressure in the absence of a detrusor contraction.
78

Detrusor Leak Point Pressure
 The DLPP was first introduced by McGuire
 An important concept in urodynamics is the fact that
bladder outlet resistance is the main determinant of
detrusor pressure
 If the outlet resistance is high, a higher bladder pressure is
needed to overcome this resistance and cause leakage.
 This high pressure can be transmitted to the upper tracts,
causing reflux and hydronephrosis.
 McGuire found that in myelodysplastic patients with an
elevated outlet resistance from a fixed external sphincter,
those with a DLPP greater than 40 cm H2O were at
significantly higher risk for upper tract deterioration
(hydronephrosis, reflux).
79

 The DLPP is the Pdet required to induce leakage
but does not determine what is causing the
elevated DLPP.
 The addition of fluoroscopy allows an accurate
method for determining the presence and
location of obstructive uropathy.
80

Technique for Measurement of
DLPP.
 The test is performed during cystometry.
 The urethral meatus is observed for leakage while
bladder pressure is measured.
 When leakage of urine is noted, the Pdet at that
instant is recorded as the DLPP .
 DLPP greater than 40 cm H2O, there was a
significantly greater risk of
upper tract deterioration.
81

Abdominal Leak Point Pressure
 Abdominal pressure does not open a normally
positioned and closed urethral sphincter.
 Leakage can be caused only by an increase in
abdominal pressure when the urethra is
abnormal.
 This led to the development of the Valsalva or
abdominal leak point pressure (VLPP, ALPP)
( McGuire et al, 1993 ).
82

 Testing for ALPP should be done during cystometry
after the bladder has been filled to at least 150 to 200
mL.
 The patient is then asked to do a Valsalva maneuver
until he or she leaks .
 The lowest pressure at which incontinence occurs is
the VLPP.
 If no leak occurs at measured abdominal pressures of
100 to 140 cm H2O, the patient is asked to cough until
incontinence occurs.
 If there is no leakage with Valsalva or cough at this
volume, the test is repeated with a volume of 300 mL,
then again at capacity.
83

84

 When there is no leakage at high pressures (>150
cm H2O), the urethra is unlikely to be the cause of
the patient's incontinence.
85

 The VLPP or ALPP is reproducible and correlates
well with the grade of symptoms, severity of
incontinence, pad usage, and incontinence
quantification.
 A VLPP less than 60 cm H2O indicates the
presence of significant ISD;
 a VLPP of 60 to 90 cm H2O is equivocal, suggesting
a combination of urethral hypermobility and
some component of ISD; and
 pressures greater than 90 cm H2O suggest urethral
hypermobility and minimal ISD.
86

Urethral Pressure Studies
 Two variations of this measurement are
commonly reported:
 The static urethral pressure profile (UPP), with its
variants the stress UPP and pressure transmission
ratios, and
 The micturitional UPP.
87

Static Urethral Pressure
Profilometry
 The urethral pressure is defined by the ICS as the
fluid pressure needed to just open a closed
urethra
 The UPP is a graph indicating changes in the
intraluminal pressure along the length of the
urethra.
88

 The UPP is obtained by recording the intraluminal pressure
changes along the length of the urethra without voiding.
 A small (6 to 10 Fr) fluid-filled catheter with circumferentially
positioned side holes is withdrawn from the urethra at a rate of
0.5 cm/sec using a mechanical puller (although withdrawing the
catheter slowly by hand may also be reliable) while the catheter is
perfused with liquid at 2 mL/min.
 The recorded urethral pressure corresponds to the pressure
needed to keep the urethra open by lifting the wall off the
catheter holes ( Yalla et al, 1980 ; Steele et al, 1998 ).
 Ideally, bladder pressure is also measured to nullify the effects of
an associated bladder contraction.
 The study may be performed at rest (static UPP) or with
intermittent stress events superimposed (stress UPP).
89

Stress Urethral Pressure
Profilometry
 This is a UPP performed while the patient performs
periodic stress maneuvers (cough) and while
intravesical pressure is also recorded.
 Normally, in women the proximal urethra is
supported intra-abdominally and increases in intra-
abdominal pressure are transmitted to both bladder
and the proximal urethra.
 If this is not observed on the stress UPP, the
implication is that the urethra has fallen outside the
intra-abdominal influence (urethral hypermobility)
or the urethra is too rigid or scarred to be influenced
by this extrinsic compression.
90

 This study is used to identify the presence and
location of bladder outlet obstruction.
 It is performed in a similar fashion to the static UPP
except that the patient voids as the catheter is
withdrawn.
 This allows bladder pressure to be compared with
urethral pressure at points along the urethra.
 During voiding, bladder pressure should be close to
urethral pressure (isobaric).
 If obstruction exists in the urethra, the pressure distal
to the obstruction is low while the bladder pressure,
and the pressure proximal to the obstruction, is high.
 Thus, if a significant drop is encountered on catheter
withdrawal, this corresponds to the site of the
obstruction.
Micturitional Urethral Pressure Profilometry
91

AMBULATORY URODYNAMICS
 Ambulatory urodynamic monitoring (AUM) is the
functional testing of the lower urinary tract, utilizing
natural filling and reproducing the patient's everyday
activities
 It is a well-established method for investigating lower
urinary tract function while freeing the patient to be
independent and to perform activities that provoke the
urinary symptoms in question.
 Its greatest benefit seems to be in patients in whom
conventional urodynamics is unsuitable or unable to
reproduce the symptoms that are being investigated.
92

Guidelines for the performance of AUM
by the ICS
 First,
 detailed instructions about recording of symptoms,
 identification of catheter displacement, and
 hardware failure should be given to the patient.
 Before the ambulatory investigation,
 patients receive an extensive information sheet describing
the test and
 the necessary preparation.
 They are also provided with a simple diary to record
events,
 allowing correlation of the test outcome with symptoms.
 The patient is advised to empty the bowel, and urine is
checked for infection.
93

 measure intravesical and abdominal pressures using
fluid-filled lines, microtip transducers allow greater
mobility.
 Catheters are placed and secured firmly and the data
are transmitted to a portable recording device .
 Flow measurements can be made using home
uroflowmetry techniques, and
 incontinence can be measured using standard pads .
 Initial checks on signal quality by testing of recorded
pressure by coughing and abdominal straining in the
supine, sitting, and erect positions.
 Regular cough tests should be carried out by the
patient throughout the study to serve as a quality
check during interpretation.
94

 Dis advantages
 lack of minute to minute control on validity of the
signals.
 position and fixation of the catheters
 dislodgement of the devices.
 the diary and data points.
 This heavy reliance on patients' compliance may
be a source of significant error
95

 Analyses of the AUM tracings are always performed
retrospectively, making them time consuming and labor
intensive.
 This should be done by a well-trained specialist ( van Waalwijk
van Doorn et al, 2000 ).
 The examiner must assess the quality of data recorded by
evaluating several points.
 The trace must be carefully examined for activity, which should
have fine second-to-second variation;
 the cough tests and other activities that cause abdominal
pressure changes must be regularly present; and
 the subtraction must be adequate with minimal change in the
derived detrusor pressure with coughing.
 The patient's diary is invaluable to improve the detailed analysis
of events occurring during AUM.
96

Applications of Ambulatory
Urodynamic Monitoring
 Several studies have shown AUM to be more
sensitive for detection of unstable detrusor
contractions, making it helpful when a CMG is
nondiagnostic .
 Another use of AUM is in patients with borderline
findings of obstruction and nondiagnostic PFSs.
 Studies in both men with chronic retention and
patients with neurogenic bladder have noted that
filling pressures with AUM tend to be significantly
lower than those with a conventional CMG
97

URODYNAMIC ANALYSIS AND
INTERPRETATION
 A good urodynamic study is one that is easy to
analyze and would allow any urodynamicist to
come to the same conclusions.
 The importance of monitoring the study in real
time in order to obtain the highest quality data
cannot be overemphasized .
 Analysis of ambulatory studies will remain
problematic, as it is less easy to conduct real-time
quality assessment.
98

 The ICS in 2002 also has clearly stated that
 “the urodynamic test should be repeated if the
initial test suggests an abnormality, leaves the
cause of troublesome LUTS unresolved, or if there
are technical problems preventing proper analysis.
If a study is inconclusive, one should consider the
consequences of not establishing a clear finding.
For instance, if an invasive therapy such as surgery
is planned, the urodynamics should be repeated or
the surgery deferred.”
99

KEY POINTS
 The goal in performing urodynamics is to answer
specific questions related to the patient's storage and
voiding function.
 The simplest and least invasive tests can be used
initially with progression to more sophisticated testing
when the clinical examination and more simple tests
cannot make an accurate diagnosis.
100

 A well-prepared and counseled patient can contribute
extensively to a good urodynamic study.
 All urodynamic procedures should be performed with
a clear indication and a specific question that can be
answered by the study.
 Many medications may affect urodynamic outcomes
and should be stopped with an adequate washout
period prior to the test.
 The International Continence Society has also
developed minimum technical specifications for
equipment and conductance of urodynamics. 101

 The standard catheter for routine urodynamics should
be a transurethral, double-lumen catheter.
 Cystometry must reproduce the patient's normal
clinical status in order to diagnosis and guide therapy.
Patients' understanding and compliance in conducting
the study are absolutely necessary, and a standardized
method must be followed in order to optimize
results.
 Cystometry should evaluate five aspects of bladder
function: sensation, capacity, compliance, stability,
and emptying.
102

 Videourodynamics are indicated when a diagnosis
cannot be made with certainty without simultaneous
evaluation of the structure and function of the urinary
tract because they give information on anatomic
abnormalities.
 Detrusor pressure is the component of intravesical
pressure created by both active and passive forces from
the bladder wall and is derived by subtracting the Pves
from Pabd (Pdet = Pabd - Pves).
 Any urodynamic test should be repeated if the initial
test suggests an abnormality or leaves the cause of
symptoms unresolved and when there are technical
problems preventing proper analysis.
103

 A VLPP of less than 60 cm H2O indicates the presence
of significant ISD;
 a VLPP of 60 to 90 cm H2O is equivocal, suggesting a
combination of urethral hypermobility and some
component of ISD; and
 pressures greater than 90 cm H2O suggest urethral
hypermobility and minimal ISD.
 Several studies have shown AUM to be more sensitive
than a conventional cystometrogram for detection of
unstable detrusor contractions, making it helpful when a
CMG is nondiagnostic. 104

105

URODYNAMIC EVALUATION

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