Why Urodynamics?

• To reproduce the patient’s symptoms and define the most significant abnormality

• To provide an explanation for the patient symptoms which will:

– To allow selection of most appropriate treatment

– Predict post operative problems • SUI/ OAB; is it MUI and is there voiding dysfunction?

• Male LUTS; to maximise good treatment outcome

• Neurological disease; bladder safety & symptoms

Why Urodynamics?

Symptoms are unreliable for diagnosis

• 11 – 16% of women with symptoms suggesting stress incontinence have detrusor overactivity

Shepherd et al. J Obstet Gynaecol 1982; 3: 123

–Bryne et al. Br J Urol 1987; 59: 228

–Lagro-Janssen et al Br J Urol 1991; 67: 569

• Up to 22% of women with OAB symptoms have Urodynamic Stress Incontinence

–Jarvis et al Br J Obstet Gynaecol 1980; 87: 893

When Urodynamics?

Urodynamic evaluation is recommended:

– prior to invasive treatments (NICE: not necessary)

– after treatment failure

– as part of a long-term surveillance program in neurogenic patients

– in "complicated cases”

Urodynamic studies should only be performed after a full basic urogynaecological assessment

What is: Urodynamics

• The investigation of the function of the

lower urinary tract - the bladder and

urethra - using physical measurements

such as urine pressure ,flow rate and

volume.

• What happens when bladder voids?

• What happens when bladder fill?

WHAT DOES URODYNAMICS COMPRISE OF?

UROFLOWMETRY CYSTOMETRY

• The simplest assessment of voiding dysfunction – measurement of urinary flow rate

• Device that measures and indicates the volume of fluid passed per unit time (ml/s)

• Often coupled with post-void bladder scan

Voiding Function Assessment

Uroflowmetry Free flow

Voiding Phase of cystometry

Uroflowmetry

• The most important

figure is maximum

flow rate (Q-max).

• It depends on age,

sex and voided

volume.

• Also take into

consideration:

– Curve shape.

– Post void residual.

Uroflowmetry: Q-max

• >15 mls/sec- Voiding

dysfunction is

unlikely.

• 10-15 mls/ sec –

Borderline.

• < 10 mls/ sec-

Voiding dysfunction is

very likely.

Age Minimum

Volume

mls/sec

14-45 200 18

46-65 200 15

66-80 200 10

Poor Flow Rate

Obstruction

Anatomical: Constrictive

Compressive

Functional:

DSD

Hypocontractile detrusor

Cystometry

Poor Flow Rate-Obstruction:

Compressive Constrictive

Cystometry

• Measures the pressure/volume relationship of the bladder

• Measurement of detrusor pressure during – controlled bladder filling

– subsequent voiding with measurement of flow rate

• Used to assess detrusor activity, sensation, capacity and compliance

Technique – filling cystometry

• 4 essential measurements: 1. Intravesical pressure (Pves)

2. Rectal pressure [≡abdominal] (Pabd)

3. Detrusor pressure (Pdet = Pves – Pabd)

4. Urine flow rate to detect leaks

• Other optional measurements include: 1. Bladder volume

2. Electromyography

3. Urethral pressure

Technique – filling cystometry

• 4 essential measurements: 1. Intravesical pressure (Pves)

2. Rectal pressure [≡abdominal] (Pabd)

3. Detrusor pressure (Pdet = Pves – Pabd)

4. Urine flow rate to detect leaks

• Other optional measurements include: 1. Bladder volume

2. Electromyography

3. Urethral pressure

Filling

• What to do with the residual?

• Pves is measured via a urethral catheter

• Bladder is filled via UC (sterile H2O, 0.9% NaCl or contrast).

• Filling ideally done with patient sitting or standing (for females), otherwise may miss detrusor overactivity.

• Slow-fill 10 ml/min

• Medium-fill 10-100 ml/min

• Fast-fill > 100 ml/min

Detrusor pressure

• Cannot be measured

• It is estimated/calculated

by the automatic

subtraction of rectal

pressure (an index of IAP)

from the total bladder

pressure, thus removing

the influence of artefacts

produced by abdominal

straining

Pdet = Pves - Pabd

New Microsoft Office Publisher Document.pub

Bladder sensation

Assessed during filling – First DV normally about 50% bladder

capacity

– Normal DV The feeling that leads patient to void

at next convenient moment; about75% bladder capacity

– Strong DV Persistent desire to void without fear of leakage; about 90% bladder capacity) – Urgency persistent desire to void with fear of

leakage – Pain Pain during filling or voiding is

abnormal

Normal / stable bladder

USI + cough induced DO

Detrusor activity

• During filling this can be either normal or

increased (overactivity)

• Detrusor overactivity exists, when, during

the filling phase, there are involuntary

detrusor contractions

DO

Videocystometrography

• Uses contrast medium instead of saline

• Assesses position and mobility of bladder neck and urethra

• Diagnoses anatomical and functional abnormalities

• Expensive

• Involves radiation

When to Video • Failed anti- incontinence

surgery to differentiate

urethral hyper-mobility

from intrinsic sphincter

deficiency.

• Previous inconclusive

conventional

urodynamics.

• Neuropathic patients

mainly to exclude reflux

and upper tract dilatation

in patient with high

pressure/ Low flow

Thank you