URODYNAMICS

URODYNAMICS
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

INTRODUCTION
Dynamic study of the
transport, storage, and
evacuation of urine.
Series of tests to gain
information about urine
storage and evacuation
3

THREE IMPORTANT RULES BEFOR UDE…
1. Decide on questions to be answered
before starting a study.
2. Design the study to answer these
questions.
3. Customize the study as necessary.
4

THREE CRITICAL “GOOD URODYNAMIC PRACTICE ELEMENTS”
Have a clear indication
for, and appropriate
selection of, relevant
test measurements and
procedures.
01
Ensure precise
measurement with data
quality control and
complete
documentation.
02
Accurately analyze and
critically report results.
This includes interpreting
UDS in the context of a
patient ’ s history and
symptoms.
03
5

WHY UDE???
To diagnose the underlying cause of lower urinary tract dysfunction
To characterize the lower urinary tract dysfunction
To Formulate treatment strategies
To Improve therapeutic outcomes
To Educate patients regarding their condition
6

AIM
 Reproduce the troublesome symptoms
 Answer specific clinical questions
 Establish a precise diagnosis
 Determine the severity of the condition
 Plan further investigations or therapies
Urologist’s Stethoscope 7

INDICATIONS
Optional or even unnecessary
when:
• A conservative treatment is
planned.
• In patients with uncomplicated
stress urinary incontinence.
• In patients with neurogenic
bladder at low risk of renal
complications (multiple sclerosis).
Useful when:
• The patient’s symptoms do not
correlate with objective findings
(complex symptoms).
• Prior therapies have failed.
Strongly recommended
• In females with urinary
incontinence or pelvic organ
prolapse when an invasive
procedure is planned
• In men with voiding symptoms to
assess if symptoms are due to
bladder outlet obstruction or
detrusor underactivity when
TURP is planned
• In patients with neurogenic
bladder who will require long
term urologic management to
establish a baseline
8

THINGS TO
DO BEFORE
PROCEEDING
TO UDE…
Proper Clinical History
Voiding diary
Urine culture – Exclude UTI
Physical Examination
• Local & systemic examination
• Neurological evaluation – Integrity of sacral arc
9

COMPONENTS
Uroflowmetry
Postvoid residual (PVR) urine volume
Cystometrogram
Pressure Flow studies of voiding
Electromyogram
Urethral pressure profilometry
Videourodynamics
10

UROFLOWMETRY
 Simplest and often most useful
 Non invasive & inexpensive
 Normal - if the patient voids at least 200 mL over 15 to 20
s, and it is recorded as a smooth single curve with a
maximum flow rate greater than 20 mL/sec
 Voided volume should be between 150 – 400 ml
11

TERMINOLOGY
Flow rate (Q): Volume of fluid expelled via the urethra per unit time (ml/s)
Voided volume (Vvoid): Total volume expelled via the urethra(ml)
Maximum flow rate (Qmax): Maximum measured value of the flow rate after correction for artifacts
Voiding time:Total duration of micturition (s)
Flow time:Time over which measurable flow actually occurs
Average flow rate (Qave):Voided volume divided by the flow time
Time to maximum flow: Elapsed time from onset of flow to maximum flow
12

NORMAL
FLOW
PATTERN
13

COMPRESSIVE OBSTRUCTION
 Pattern of flow seems normal til Qmax
(lower than normal) with a terminal
prolongation.
 Average flow is typically lower than
normal.
 BPH
14

OUTFLOW OBSTRUCTION
15

CONSTRICTIVE OBSTRUCTION
 A low Qmax is rapidly reached, and
the flow rate remains relatively
constant, giving to the curve a plateau-
shaped appearance
 Urethral Stricture
16

URETHRAL STRICTURE
17

STACCATO CURVE
 Fluctuations in the flow curve due to
burst of involuntary external sphincter
contractions during voiding.
 Dysfunctional voiding
18

INTERMITTENT FLOW
 A flow that stops and starts several
times during voiding
 Abdominal straining or neuropathic
sphincter dyssynergia
19

SUPERVOIDER / FAST BLADDER
 Very high Qmax with very rapid
upstroke and downstroke.
 Not diagnostic, but people (mostly
females) with detrusor overactivity or
stress urinary incontinence may have a
flow rate at the top of the range
20

ARTEFACTS
 Accidental Kick
 Abrupt peak recorded by the machine
during voiding.
 Computerized reading Qmax - 50ml/s
 Actual Qmax - 30 ml/s
21

ARTEFACTS
 Voiding by straining.
 Computerized reading: Qmax - 45
ml/s
 Manual assessment of flow using
smooth curve: Actual Qmax - 15 ml/s
22

ARTEFACTS
 Compression of the glans.
 Initial peak followed a regular flow
curve.
 Computerized reading, Qmax: 45 ml/s.
 Manual reading, Qmax: 23 ml/s
23

ARTEFACTS
 A - spurious maximum flow rate of 19
ml/s) results from squeezing the
prepuce of the penis during voiding.
 B - It is eliminated revealing a true
maximum flow rate of 7.4 ml/s when
the patient stops squeezing the penis
24

POSTVOID RESIDUAL URINE
 Up to 25 ml & PVR less than 10% of the total
bladder volume - normal
 Between 50 and 100 ml - interpreted in the clinical
context
 Values greater than 150 ml - pathological
25

MULTICHANNEL URODYNAMICS
26

MULTICHANNEL
URODYNAMICS
27

URODYNAMIC SETUP
28

PRESSURE/FLOW WORK STATION
 A -Transducers on adjustable height
stand
 B - Pump for bladder filling
 C – Display with superimposed
screening image in videourodynamics
 D - uroflowmeter
B
A
C
D
29

VIDEOURODYNAMICS
30

LAYOUT OF GRAPHICAL DISPLAY - ICS
 Intra-abdominal pressure (Pabd) is
displayed at the top
 Intra-vesical pressure (Pves) next
 Subtracted detrusor pressure (Pdet) next
((Pdet = Pves − Pabd))
 Urinary flow rate (Q) is displayed at the
bottom
 Infused volume, voided volume, urethral
pressure, EMG traces and video screening
images can be displayed optionally.
Uroflowmetry 31

CATHETERS
 Fluid-filled catheter with external pressure transducer
 Air-charged catheter with external pressure transducer
 Microtip transducer
32

FLUID FILLED CATHETERS
 Records the pressure into the bladder and rectum 
transmits to the external transducer through a non
compressible column of water inside the catheter and
connecting line
 Low cost & disposable
 Disadvantage - signal artifacts due to obstruction of
intraluminal air bubble within the catheter (damping
phenomenon). 33

AIR CHARGED CATHETERS
 Filled with air and the pressure is
transmitted directly from the catheter
tip to the external transducer.
 Advantage: Absence of classical
damping phenomenon and the lack of
motion artifacts created by movement
of the line.
 Disadvantage: Slow response to
pressure variations and in general an
attenuation of the transmitted signal
34

SOLID STATE MICROTIP CATHETERS
 Small transducer mounted on the tip that detects
pressure changes  electric signal  amplified and
transmitted to semiconductor  converted into
pressure measurement
 Advantage: Faster response in pressure change
recording and minimal motion artifacts; suitable for
ambulatory urodynamics
 Disadvantages: cost, the need for sterilization, fragility
35

MICROTIP CATHETERS
 Dual intra-vesical and urethral measuring microtip
catheter with transducer visible distally and further
urethral transducer visible a few centimetres more
proximal.
36

SETUP OFTHE
PATIENT
37

STEP 1
 Step 1: EMG electrode placement
 Position the electrodes on the skin around the
patient anus and on the thigh to act as the ground
lead
38

STEP 2
 Step 2: Sterilizing the urethra
39

STEP 3
 Step 3: Post-void residual urine
measurement
 Drain the bladder with a catheter to
obtain a post-void residual urine
measurement.
40

STEP 4
 Step 4: Catheter insertion into the bladder
and rectum
 In female advance the catheter into the
bladder 8 – 10cm
 In males, do not advance it more than 24
centimeters.
 For rectal placement - to a depth of
approximately 10-15cm
 Once inserted, each catheter should be
securely fixed and then connected to its
respective cable. 41

STEP 5
 Step 5: Flushing
 Free the catheters of air inside the channel by
flushing with infusion fluid
42

STEP 6
 Step 6: Zeroing UDS machine
 Atmospheric pressure taken as zero
 Reference height - Superior border of the symphysis
pubis –Transducers placed at this level
 The syringe and catheter connection is blocked, while
the 3-way taps of the transducers are opened to
atmospheric pressure and the “zero all” button is
pressed.
 By this way, all the three lines Pves, Pabd, and Pdet
show “zero” reading. 43

44

POSITION OF EXTERNAL FLUID FILLED
TRANSDUCERS
Set at the level of the pubic symphysis to
allow standardization and comparison.
Increasing the height of the external
transducer lowers the measured pressure
Lowering the height increases the
measured pressure.
The position of the catheter in the organ
has no effect on the measured pressure.
45

POSITION OF MICROTIP TRANSDUCER / AIR
FILLED BALLOON
The position of the internal transducer or
balloon within the bladder alters the
measured pressure.
If the position is lower, then a higher pressure
will be measured due to the extra fluid
column above the transducer/balloon
High position will therefore have a lower
pressure
46

BASELINE PRESSURE CHECK
Pdet should show a near-zero value (<6 cmH 2 O) since
Pves and Pabd are equal and detrusor activity is absent
with
bladder empty
47

48

RESTING DETRUSOR PRESSURE
If the Pdet is too high (>6 cm H2O) or negative
CHECK THE POSITION OF
RECTAL ANDVESICAL
CATHETER
EXCLUDE KINKS AND LEAKS
FLUSH THE SYSTEM TO REMOVE
ANY AIR BUBBLES
Due to the pressure subtraction the Pdet should be <6 cm
H2O and ideally as close to zero as possible.
49

STEP 7
 Step 7: Checking the quality of signals
 Checked by asking the patient to gently
cough.
 Both Pabd and Pves respond equally with
a rapid peak and rapid drop and the
detrusor line should be unaffected.
 A small biphasic deflection is normal, but
any rise or fall in the detrusor pressure
during cough suggests a dampening in the
vesical or abdominal system.
50

DAMPENING EFFECT
Air bubble being compressed and ‘absorbing’ some of the pressure wave leading to
reduced transmission and a lower baseline and lower deflection on the trace.
51

QUALITY
CHECK &
EFFECT OF
DAMPENING
52

9 Cs of PRESSURE FLOW STUDIES
STORAGE PHASE – 5 Cs
 Contractions (involuntary
detrusor)
 Compliance
 Coarse sensation
 Continence
 Cystometric capacity
VOIDING PHASE – 4 Cs
 Contractility
 Complete emptying
 Coordination (Detrusor
sphincter)
 Clinical obstruction
53

NORMAL
STORAGE
REFLEX
54

NORMAL
MICTURITION
REFLEX
55

TWO PHASES OF CYSTOMETRY
 Storage/filling phase (also termed as FILLING CYSTOMETRY):
 Commences when the pump is turned on
 Ends when the patient and the urodynamacist decide that ‘permission to void’ has been
given (usually at maximum tolerated capacity).
 Voiding phase (also termed asVOIDING CYSTOMETRY):
 Commences when the patient and the urodynamicist decide that ‘permission to void’ has
been given, or when uncontrollable voiding begins
 Ends when the patient considers that voiding has finished.
56

4 PHASES OF CYSTOMETRIC BLADDER FUNCTION
1. Initial small increase in intravesical
pressure at the beginning of filling
2. Stable pressure that comprises the
majority of the filling phase
3. Terminal pressure rise at bladder
capacity, representing the limit of
viscoelastic expansion (often not
reached due to discomfort)
4. Voiding phase with an inconsistently
observed small increase in intravesical
pressure
57

FILL RATE
The rate of filling should have been decided prior to
beginning the procedure.
• Slow fill: <10 ml/min – a more ‘physiological’ filling rate, used in
neurogenic patients.
• Medium fill: 10–100 ml/min – the most frequent fi lling rate.
• Rapid fill: >100 ml/min – a very rapid provocative fi lling rate.
The ICS originally categorised this into three fill rates:
58

STORAGE PHASE MEASURES
 BLADDER SENSATION
 BLADDER COMPLIANCE
 DETRUSOR FUNCTION
 CYSTOMETRIC BLADDER CAPACITY
 URETHRAL FUNCTION DURING STORAGE PHASE
 ABDOMINAL LEAK POINT PRESSURE
 DETRUSOR LEAK POINT PRESSURE
59

NORMAL SENSATION
First sensation of bladder filling – 170 – 200 mL or
~ 50% of Maximum cystometric capacity (MCC)
First desire to void ~ 250mL or ~75% of MCC
Strong desire to void ~ 400 or ~90% of MCC
60

BLADDER SENSATION
Increased – an early first sensation or an early
desire to void and/or an early strong desire to
void, which occurs at a low bladder volume and
which persists
Reduced – diminished sensation throughout
bladder filling
61

DETRUSOR
HYPERSENSITIVITY
Strong desire to void occurring at low filling volume without any
detrusor contraction. Increased sensation leads to small leakage of
62

BLADDER COMPLIANCE
 Compliance (ml/cm H O) = Change in volume (Δ V) / change in detrusor pressure (ΔPdet)
 Normal compliance is >30–40 ml/cm H2O.
 Abnormal compliance is <30–40 ml/cm H2O.
63

BLADDER COMPLIANCE
A) Normal compliance with each 30–40
ml increase in bladder volume causing
a less than 1 cm H2O increase in
pressure.
B) Seemingly poor compliance.
C) Artefactual poor compliance due to
high fill rate
D) True poor compliance: stopping filling
does not cause a drop in pressure and
filling further at any fill rate continues
to show poor compliance.
64

BLADDER CAPACITY
Cystometric capacity
 Bladder volume at the end of the storage phase
when ‘permission to void’ is given and the
investigation moves into the voiding phase.
 Usually the maximum cystometric capacity
 If it is not the MCC – define the reason why
fIlling was stopped
 pain, large infused volume or high detrusor
end filling pressure.
Maximum cystometric capacity (MCC)
 Normal sensations - volume at which the
patient feels he/she can no longer delay
micturition due to a strong desire to void.
 Where there is altered or absent sensation the
MCC cannot be measured and the cystometric
capacity should instead be recorded.
 Normal – 350 – 600ml
NORMAL - bladder should fill to a capacity of approximately 500 ml before there is a strong desire to void.
NO BENEFIT IN OVERFILLING ABOVE 650 -700 ML
65

DETRUSOR FUNCTION
 Normal detrusor function – During the storage phase, the bladder should be
relaxed and compliant to bladder filling with little or no change in detrusor pressure.
 Involuntary detrusor activity - Any detrusor activity prior to the voiding phase
66

DETRUSOR OVERACTIVITY
 Involuntary detrusor contractions (IDCs) during the storage phase
 Previous terminology - detrusor instability or detrusor hyper-reflexia
 Types:
 Phasic – having a characteristic waveform of repeated waves of DO.
 Terminal – an IDC occurring at cystometric capacity, which cannot be suppressed, and
results in incontinence/voiding.
 Idiopathic – when there is no defined cause for the overactivity – OVERACTIVE
BLADDER SYNDROME
 Neurogenic – when there is an underlying neurological condition causing the lower
urinary tract dysfunction.
67

DETRUSOR OVERACTIVITY – THINGS TO
LOOK IN UDE
 Volume at which the contraction occurred
 Rise in amplitude above the baseline
 Duration of the contraction
 If urgency was experienced in association with the
IDC
 Associated incontinence
68

HIGH PRESSURE DETRUSOR OVERACTIVITY
• Neurogenic detrusor
activity
69

PHASIC DETRUSOR OVERACTIVITY
Contraction activity with
increasingly frequent and
higher amplitude contractions
occur as the bladder
continues to be filled
70

TERMINAL
DETRUSOR
OA
Strong detrusor contraction occurring at urgency and
leading to complete bladder emptying.
71

COUGH INDUCED DETRUSOR OVERACTIVITY
• Det. OA associated
with increased intra
abdominal pressure
• Associated with
increased detrusor
pressure
• Should be differentiated
from stress urinary
incontinence when
associated with urine
leak
72

URETHRAL FUNCTION DURING STORAGE
PHASE
 Normal – maintains continence in the presence of increased intraabdominal
pressure.
 Incompetent – allows leakage in the absence of a detrusor contraction.
 Urodynamic stress incontinence (USI) – involuntary leakage of urine during
increased intra-abdominal pressure, in the absence of a detrusor contraction
 Urethral relaxation incontinence – leakage due to urethral relaxation in the
absence of raised intra-abdominal pressure or detrusor overactivity.
73

LEAK POINT PRESSURES
 Abdominal leak point pressure (ALPP)
 Detrusor leak point pressure (DLPP)
74

ABDOMINAL LEAK POINT PRESSURE
 Intra-vesical pressure at which urine
leakage occurs due to increased
abdominal pressure in the absence of a
detrusor contraction.
 Measure of the ability of the bladder neck
and the urethral sphincter mechanism to
resist increases in intra-abdominal
pressure.
 Other terms -Valsalva leak point pressure
(VLPP), Cough leak point pressure
(CLPP)
ALPP (cm H2O) INFERENCE IN
INCONTINENCE
<60 Intrinsic sphincter
deficiency
60- 100 Equivocal
>100 Urethral
hypermobility
75

ALPP
76

URODYNAMIC STRESS INCONTINENCE
Leakage occurs during cough
without any concomitant detrusor
contraction
77

DETRUSOR LEAK POINT PRESSURE
 Lowest detrusor pressure at which urine leakage occurs in the absence of either a
detrusor contraction or increased abdominal pressure.
 Predicts upper tract dysfunction in patients with reduced bladder compliance and
poor voiding.
 Measures the capacity of the bladder neck and urethral sphincter mechanism to
resist increased pressure
Detrusor leak point pressure (DLPP) >40 cm H2O: suggests upper tract
deterioration likely
78

DETRUSOR LEAK POINT PRESSURE
79

VOIDING PHASE
Isovolumetric
contraction -
detrusor
initially
contracts
without a
change in
bladder volume
Bladder
continues to
contract -
Bladder outlet
‘opens’ and
urine begins to
be expelled
resulting in a
decrease in the
bladder volume
At the
completion of
voiding the
detrusor
relaxes and the
urethra/bladder
outlet ‘closes’
80

VOIDING PHASE MEASURES
FLOW PARAMETERS
 Flow rate (Q)
 Maximum flow rate (Qmax)
 Voided volume
 Voiding time
 Flow time
 Average flow rate
 Time to maximum flow.
PRESSURE PARAMETERS
 Pre-micturition pressure
 Opening pressure
 Opening time
 Maximum pressure
 Pressure at maximum flow
 Closing pressure
 Minimum voiding pressure
81

PRESSURE PARAMETERS INVOIDING
 Pre-micturition pressure – the pressure recorded immediately before the initial
isovolumetric contraction. (Clinically relevant – Detrusor pre-micturition Pressure)
 Opening pressure – the pressure recorded at the onset of urine flow. (clinically
relevant –Vesical opening pressure)
 Opening time – the time from initial rise in detrusor pressure to onset of fl ow; this
refers to the initial isovolumetric contraction period.
 Maximum pressure – the maximum value of the measured pressure, i.e. the peak
amplitude of the voiding pressure curve (Clinically relevant – Pdetmax)
82

PRESSURE PARAMETERS INVOIDING
 Pressure at maximum flow (Pdet@Qmax) – the pressure recorded at
maximum measured flow rate.
 Closing pressure – the pressure measured at the end of measured flow. (Clinically
relevant – Intravesical closing pressure)
 Minimum voiding pressure – the minimum pressure during measurable flow
83

84

FLOW RATE DELAY
 Flow delay is the time delay between a change in bladder pressure and the
corresponding change in measured flow rate.
 Delay due to the time the urine leaves the urethral meatus until they are measured
by the flowmeter.
 Usually between 0.5 and 1 second, but can be as long as 2 seconds.
 Calculated for the equipment in use and a correction made when correlating flow
rates to pressure measurements
85

FLOW RATE DELAY CORRECTION
 To correct for the delay the flow
rate trace should be moved to
the left by an amount equal to
the flow delay.
 The measured pressures will
then correspond with the flow
rates achieved by those
pressures
The red line shows the recorded flow rate; which
must be shifted to the left (blue line) by the amount
of the delay, to determine the actual position of the
flow trace in relation to the pressure readings.
86

NORMALVALUES INVOIDING PHASE
 Maximum detrusor pressure of 25–50 cm H2O
 The maximum urinary flow rate should be:
 over 30–35 ml/s in women
 over 25 ml/s in men under 40 years
 over 15 ml/s in men over 60 years.
 Pves@Qmax: 15–120 cmH 2 O
 Pabd@Qmax: 20–40 cmH 2 O
 Pdet@Qmax: 44–107 cmH 2 O 87

DETRUSOR FUNCTION INVOIDING
 NORMAL
 DETRUSOR UNDERACTIVITY
 ACONTRACTILE DETRUSOR
 AFTER CONTRACTION
88

NORMAL DETRUSOR
 Voluntary continuous detrusor contraction which leads to complete emptying of the
bladder within an acceptable time span
89

DETRUSOR
UNDERACTIVITY
 Contraction of reduced
strength and/or duration,
resulting in prolonged
bladder emptying and/or
a failure to achieve
complete bladder
emptying within a normal
time span.
90

BLADDER CONTRACTILITY INDEX
 BCI = Pdet Qmax + 5 Qmax
 Measure of detrusor function
BCI (cmH2O) INFERENCE
>150 STRONG
CONTRACTILITY
100-150 NORMAL
<100 WEAK
CONTRACTILITY
91

ACONTRACTILE BLADDER
 Does not demonstrate any contractile activity during urodynamic assessment.
 CONSIDER!!! - ‘bashful’ bladder - cannot generate a detrusor contraction in the
laboratory setting
92

AFTER CONTRACTION
 A detrusor contraction which occurs
immediately after micturition has
ended
 Significance - unknown
 May be associated with detrusor
overactivity
93

URETHRAL FUNCTION INVOIDING
 Normal
 Bladder outlet obstruction
 Dysfunctional voiding
 Detrusor sphincter dyssynergia
 Non-relaxing urethral sphincter obstruction
94

NORMAL ELECTROMYOGRAM
EMG activity
increases during
bladder filling
and should be
almost silent
during voiding
(sphincter
relaxation) 95

BLADDER OUTLET OBSTRUCTION
URODYNAMIC
OBSTRUCTION:
• Detrusor pressure >60 cm H2O
• Qmax <10 mL/s
96

BOO WITH DO
Pressure/flow trace in patient with
both detrusor overactivity during
filling and BOO during voiding.
This is a common pattern as many
patients have both conditions
coexisting
97

BOO - INDEX
 Abrams–Griffiths (AG) number)
 BOOI = Pdet@Qmax − (2 × Qmax)
BOOI INFERENCE
<20 UNOBSTRUCTED
20-40 EQUIVOCAL
>40 OBSTRUCTED
98

ICS PRESSURE FLOW NOMOGRAM
Used to calculate the bladder outlet
obstruction index (BOOI)
by plotting Qmax against Pdet@Qmax.
Categorize patients as
being obstructed, unobstructed or
equivocal.
Based on a number of older nomograms
(Abrams–Griffi ths, Schafer LinPURR
and URA nomograms)
Only the ICS nomogram is required in
routine clinical practice 99

ICS NOMOGRAMS
COMBINING BOOI
& BCI
100

DYSFUNCTIONALVOIDING
 Intermittent and/or
fluctuating flow rate due
to involuntary
intermittent
contractions of the peri-
urethral striated muscle
during voiding, in
neurologically normal
patients.
101

DETRUSOR SPHINCTER
DYSSYNERGIA
 Detrusor contraction concurrent with an
involuntary contraction of the urethral
and/or peri urethral striated muscle.
 Intermittent opening and closure of the
urethral sphincter causing a characteristic
flow pattern and pressure changes
102

103

TYPES OF DSD
Characterized by a
simultaneous increase of
detrusor pressure and
external sphincter EMG
activity that reaches its
maximum at the peak of
detrusor contraction.At this
point sudden complete
external relaxation occurs
allowing urination.
01
Characterized by clonic
contractions of the
external urethral
sphincter scattered
throughout detrusor
contraction. Patients
usually void with an
interrupted stream.
02
Characterized by an
external sphincter
contraction persisting
during the entire detrusor
contraction.These
patients void with an
obstructive stream or
cannot void at all
03
104

105

NON-RELAXING URETHRAL SPHINCTER
 Non-relaxing, obstructing urethra may result in reduced urine flow and tends to
occur in patients with a sacral or infra-sacral neurological lesion
 Meningomyelocoele or radical pelvic surgery.
106

STOP TEST
 During voiding in a video urodynamic
study the male patient can be asked to
stop voiding.
 A - Normal - contrast is “milked back”
from the distal sphincter mechanism
proximally through the bladder neck
into the bladder.
 B - Obstruction at the level of the
bladder neck - contrast will be trapped
within the prostatic urethra with intra-
vesical and detrusor pressure spike 107

STOP TEST
 Isometric pressure
contraction during stop
test
 The detrusor & intravesical
pressure spike during the
stop test
 Thought to be a sign of
detrusor power
108

109

INTERPRETING CHANGES IN PRESSURE
110

URETHRAL PRESSURE PROFILOMETRY
Measured along the length of the
entire urethra by withdrawing the
measuring catheter mechanically at a
constant speed.
The resulting profile indicates the
pressures within the urethra from the
bladder neck to the meatus
Urethral closure pressure profile:
derived by the subtraction of intra-
vesical pressure from urethral
pressure.
111

URETHRAL PRESSURE PROFILOMETRY
 Maximum urethral pressure: The
maximum pressure of the measured
profile.
 Maximum urethral closure pressure
(MUCP): The maximum difference
between the urethral pressure and the
intra-vesical pressure.
 Functional profile length: The length
of the urethra along which the urethral
pressure exceeds intra-vesical pressure
Maximum urethral closure pressure <20 cm H2O: suggests intrinsic sphincter deficiency
112

AMBULATORY URODYNAMICS
 ICS DEFINITION - “any functional test of the lower
urinary tract predominantly utilizing natural filling of the
urinary tract and reproducing subject’s normal activity.”
 Study is performed over a longer period of time, usually 4
h, and allows more than one cycle of bladder filling and
voiding.
 Utilizes a natural bladder filling (a standard fluid intake of
200 ml half-hourly is recommended).
 Takes place outside the urodynamic laboratory.
 Normal activities of daily living are reproduced more easily.
113

BEFORE CONCLUDING…
Read all the pressure flow measurements in a wholistic manner
No individual measures should be interpreted separately
Interpret UDE always with clinical context
Look for artefacts and deduce them
Repeat UDE whenever necessary
114

Not as difficult as you
think…
Recommend UDE
whenever necessary…
115

THANK YOU
116

URODYNAMICS

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URODYNAMICS