urodynamicsUrodynamics • Urodynamics is an objective tool used to investigate the function of the lower urinary tract • The goal of urodynamics is to reproduce patient’s symptoms

basic pricibles of urodynamics

1. Basic Principles of
Urodynamics
Young-Suk Lee

Dept. of Urology, Sungkyunkwan University School of Medicine
Samsung Changwon Hospital

2. Urodynamics
•defined by ICS (International Continance Society) as:

“Measurement of physiological parameters
relevant to the function of the lower urinary tract”
D'Ancona C, et al. Neurourol Urodyn. 2019 Feb;38(2):433-477

3. Urodynamics
•defined by ICS (International Continance Society) as:

“Measurement of physiological parameters
relevant to the function of the lower urinary tract”
D'Ancona C, et al. Neurourol Urodyn. 2019 Feb;38(2):433-477
1.

4. Normal function of the LUT

5. BLADDER

Low pressure
reservoir
Closed valve
Coordinated valve Unobstructed
channel VOIDING
STORAGE
OUTLET
Normal function of the LUT

6. Classification of LUT dysfunction
•Failure to Store
•Because of the bladder
•Because of the outlet

•Failure to Voiding
•Because of the bladder
•Because of the outlet

7. Lower urinary tract symptom (LUTS)
Storage Voiding and post-voiding symptoms
Voiding Post-voiding symptoms
•Increased daytime
frequency
•Nocturia
•Urgency
•Urinary incontinence
Urgency incontinence
Stress incontinence
Mixed incontinence
Overflow incontinence
Functional incontinence
•Hesitancy
•Slow stream
•Intermittency
•Feeling of incomplete
emptying
•Post-micturition dribble

8. Urodynamics
•defined by ICS (International Continance Society) as:

“Measurement of physiological parameters
relevant to the function of the lower urinary tract”
D'Ancona C, et al. Neurourol Urodyn. 2019 Feb;38(2):433-477
2.

9. Physiologic parameters: Pressures
•Four pressures:
1.intravesical pressure p
ves
2.abdominal pressure p
abd
3.detrusor pressure p
det
4.urethral pressure p
ura

•Pdet is the single most useful
“pressure” that we measure.

•It tells us:
what the detrusor is doing

10. Physiologic parameters: Pressures
•Four pressures:
1.intravesical pressure p
ves
2.abdominal pressure p
abd
3.detrusor pressure p
det
4.urethral pressure p
ura

•Pdet is the single most useful
“pressure” that we measure.

•It tells us:
what the detrusor is doing

•p
det = p
ves - p
abd

11. Urethral and rectal catheters
•p
det = p
ves - p
abd

12. Urodynamics and the LUTS
•In urodynamics, we examine the lower urinary tract (bladder and urethra).
•Dysfunction anywhere in the system, from brain to bladder, causes
symptoms.
•The number of different symptoms is limited, but the number of possible
causes is large.
•Only urodynamics can make the necessary distinctions that allow therapy
to be tailored to the underlying condition.

13. Purposes of the UDS
•The aim is to reproduce the symptoms
-under controlled and measured conditions
-so as to identify the underlying causes
•To do this you need:
-technically reliable measurements
-experience, so that technique is second nature and you can
concentrate on:
→putting the patient at ease
→reproducing their usual behavior

14. Initial evaluation
•History and physical examination
•Voiding and storage symptoms
•Level of lesion: Risk of DESD
•Bladder diary
•Time, volume, incontinence, pad usage, other (fluid intake, urgency & incontinence
degree)
•Functional bladder capacity

 Urodynamic impression
Study design – position, filling rate, cystometric volume, provocation…

15. Which investigation? Essential
urodynamic tests
•UFM and PVR
•Filling cystometry
•Pressure-Flow study of voiding

•Optional tests
•EMG
•Urethral function studies
•Video UDS
•Ambulatory UDS
•Upper tract imaging

16. Bladder diary

17. Uroflowmetry & post-void residuals
•First-line Screening test
•Simple, objective, and noninvasive method to evaluate LUTS
•Should be performed when the patient experiences a normal desire to void
•minimum urine volume of 150 mL provides an accurate study
•Existing nomograms provide values with age- and volume-adjusted flow
rate.

19. Qmax/Voided volume/PVR = 5/64/350

20. Limitations of uroflowmetry
•Unable to distinguish obstructed from unobstructed patients.
•A normal flow may be seen in patients with…
•bladder outlet obstruction vs. poor detrusor function.

21. Pressure-flow study
•Synchronous measurement and display of multiple urodynamic
parameters.
•Pves and Pabd are measured during voiding, simultaneously with the
flow rate in the external stream.
•Pdet is calculated by subtracting Pabd from Pves.

22. Pressure-flow study
Low pressure
Low flow
Detrusor underactivity

23. Pressure-flow study
High pressure
Low flow
Bladder outlet obstruction

24. Filling cystometry
•Only method that can detect sensory urgency, DO, and low
bladder compliance.
• Recommend as part of the pressure-flow study (AUA
guidelines)

25. •Detrusor overactivity
involuntary detrusor contractions during the filling phase that may be
spontaneous or provoked associated with urgency

•Compliance
C =  V /  P
C; compliance, V; volume, P; pressure

•Detrusor sphincter dyssynergia (DSD)
detrusor muscle contraction with concomitant and inappropriate involuntary
urethral sphincter contraction

Filling cystometry

26. Cystometry
High pressure detrusor overactivity
Urine leakage
Detrusor overactivity

27. Cystometry
Decreased compliance
Urine leakage 시작
Low compliant bladder

28. Cystometry Detrusor sphincter dyssynergia
Detrusor overactivity
Increased EMG

29. V-CUG

30. Treating based on UDS findings
•Lower storage pressures
•Antimuscarinics
•Botulinum toxin
•Augmentation cystoplasty

•Facilitate emptying
•Intermittent catheterization
•Improve contractility
•Neural stimulation
•Sphincterotomy
•Surgical
•Botulinum toxin


•Improve sphincter function
•Sling
•AUS
•Urethral bulking

31. Case
•F/65

•C.C> Incidentally detected bilateral HN

•LUTS> Incontinence

•PMHx> 허리시술 2회 1YA (HIVD)

•Cr 1.6

34. Compliance: 230/20 = 11.5ml/cmH2O

35. Abdominal straining
Detrusor underactivity
Low flow

37. •Augmentation enterocystoplasty & ureteroneocystostomy Lt.

40. •Cr 1.1 mg/dL

41. Thank you for your attention!