Terminology in Urodynamics is defined by 

The International Continence Society


To download the ICS documents use this link


The most recent document is:

Abrams P. Cardozo L. Fall M. Griffiths D. Rosier P. Ulmsten U. van Kerrebroeck P. Victor A. Wein A. 

Standardisation Sub-committee of the International Continence Society. 

The standardisation of terminology of lower urinary tract function: report from the Standardisation Sub-committee of the International Continence Society.

Neurourology & Urodynamics. 21(2):167-78, 2002.

The previous document was:

Abrams P. Blaivas JG. Stanton SL. Andersen JT. 

The standardisation of terminology of lower urinary tract function. The International Continence Society Committee on Standardisation of Terminology.

Scandinavian Journal of Urology & Nephrology. Supplementum. 114:5-19, 1988.

The terminology underwent a radical review in 2002. In time we shall all be completely happy with the new, but for the present I have decided to publish the new along with some of the old.

Also needed is Good urodynamic Practice



The ICS does not give numerical guidelines for many numerical values capacity etc
Where these are given below they are local values.

assess: detrusor activity, sensation, capacity and compliance: Urethral competence
Detrusor Activity
Detrusor may show
New Old
  Normal Detrusor
Normal Detrusor Function allows bladder filling with little or no change in pressure.No involuntary phasic contractions occur despite provocation The stable detrusor is one that does not contract during the filling phase while the patient is attempting to inhibit micturition.
 Detrusor Overactivity is a urodynamic observation characterised by involuntary detrusor contractions during the filling phase which may be spontaneous or provoked. The unstable detrusor is one that is shown to contract spontaneously or on provocation during the filling phase while the patient is attempting to inhibit micturition.
Phasic Detrusor Overactivity is defined by a characteristic wave form, and or may not lead to urinary incontinence.
Terminal Detrusor Overactivity is defined as a single involuntary detrusor contraction occurring at cystometric capacity, which cannot be suppressed,
Detrusor overactivity incontinence is incontinence due to an involuntary detrusor contraction.
Note: In patient with normal sensation urgency is likely to be experienced just before the leakage episode.
Neuropathic Detrusor Overactivity is when there is a relavant neurological condition. Detrusor Hyperreflexia is defined as overactivity due to disturbance of the nervous control mechanism. Should only be used where there is objective evidence of neurological disorder.

Idiopathic Detrusor Overactivity is when there is no defined cause. This term replaces Detrusor Instability.
Idiopathic Detrusor Instability
Sensation may be
Normal bladder sensation can be judged by three defined points noted during filling cystometry and evaluated in relation to the baldder volume at that moment and in relation to the patients symptomatic complaints.
  First Sensation
     Bladder Filling
First sensation of bladder filling is the feeling the patient has, during filling cystometry, when he/she first becomes aware of the bladder filling.
  First Desire 
        to void
First desire to void is defined as the feeling, during filling cystometry, that would lead the patient to pass urine at the next convenient moment, but voiding can be delayed if necessary.
  Strong Desire
         to void
Strong desire to void this is defined, during filling cystometry, as a persistent desire to void without the fear of leakage.
Increased Bladder Sensation is defined, during filling cystometry, as an early first sensation of bladder filling or an early desire to void and/ or an early strong desire to void, which occurs at low bladder volume and which persists.
Reduced Bladder Sensation is defined, during filling cystometry, as diminished sensation throughout bladder filling.
Absent bladder sensation means that, during filling cystometry, the individual has no bladder sensation.
Non-specific bladder sensations, during filling cystometry, may make the individual aware of bladder filling, for example, abdominal fullness or vegetative symptoms.
  Bladder Pain Bladder pain during filling cystometry, is a self explainatory term and is an abnormal finding.
  Urgency  Urgency, during filling cystometry, is a sudden compelling desire to void.
  The Vesical/Urethral
    Sensory Threshold
The Vesical/Urethral sensory threshold, is defined as the least current which consistently produces sensation perceived by the subject during stimulation at the site under investigation.
Capacity may be
Cystometric capacity is the bladder volume at the end of the filling cystometrogram, when " permission to void " is usually given. The end point should be specified, for example, if filling is stopped when the patient has a normal desire to void. The cystometric capacity is the volume voided together with any residual volume.
Maximum cystometric capacity, in patients with normal sensation, is the volume at which the patient feels he/she can no longer delay micturation. (Has strong desire to void).
Maximum anaesthetic bladder capacity is the volume to which the bladder can be filled under deep general or spinal anaesthetic and should be qualified according to the type of anaesthesia used, the speed of filling, the length of time of filling, and the pressure at which the bladder is filled.
Small < 350 ml
Average 350 < <650
Large > 650 ml
Bladder Compliance describes the relationship between change in bladder volume and change in detrusor pressure.
Compliance is defined as DV/DP. It  has an instantaneous value - the inverse of the tangent to the cystometry curve and also depends on filling rate. One does not make statements of the form "the detrusor compliance was 10ml per cm water" In practice detrusor compliance is defined as
Low (Hypocompliant)
High (Hypercompliant)
NB. The physiologically filled detrusor is always high compliance. The rise in pressure that causes lower compliances is a function of the viscoelastic nature of the detrusor under higher filling rates. i.e. stretch the muscle too fast and it cannot accommodate completely.

The urethral closure mechanism under filling may be
Normal urethral closure mechanism  Maintains a positive closure pressure (Pura - Pves) throughout filling even in the presence of increased abdominal pressure, although it may be overcome by detrusor overactivity.   
Incompetent urethral closure mechanism 


Allows leakage of urine in the absence of a detrusor contraction. 


Genuine stress incontinence  

Urethral Function During Filling Cystometry
The urethral closure mechanism during storage may be competent or incompetent. 
   Normal urethral closure mechanism maintains a positive urethral closure pressure during bladder filling even in the presence of increased abdominal pressure, although it may be overcome by detrusor overactivity. (CHANGED)
   Incompetent urethral closure mechanism is defined as one which allows leakage of urine in the absence of a detrusor contraction.  (ORIGINAL)
   Urethral relaxation incontinence is defined as leakage due to urethral relaxation in the absence of raised abdominal pressure or detrusor overactivity. (NEW) - FOOTNOTE 31
 FOOTNOTE 31 - Fluctuations in urethral pressure have been defined as the “unstable urethra”. However, the significance of the fluctuations and the term itself lack clarity and the term is not recommended by the ICS. If symptoms are seen in association with a decrease in urethral pressure a full description should be given.
   Urodynamic stress incontinence is noted during filling cystometry and is defined as the involuntary leakage of urine during increased abdominal pressure, in the absence of a detrusor contraction. (CHANGED)
Urodynamic stress incontinence is now the preferred term to “genuine stress incontinence”.  FOOTNOTE 32
 FOOTNOTE 32 In patients with stress incontinence, there is a spectrum of urethral characteristics ranging from a highly mobile urethra with good intrinsic function to an immobile urethra with poor intrinsic function. Any delineation into categories such as “urethral hypermobility” and “intrinsic sphincter deficiency” may be simplistic and arbitrary, and requires further research.
 3.2.6.   Assessment of Urethral Function During Filling Cystometry 
  Urethral pressure measurement
 Urethral pressure is defined as the fluid pressure needed to just open a closed urethra. (ORIGINAL)
  The Urethral pressure profile is a graph indicating the intraluminal pressure along the length of the urethra. (ORIGINAL)
  The Urethral closure pressure profile is given by the subtraction of intravesical pressure from urethral pressure. (ORIGINAL)
  Maximum urethral pressure is the maximum pressure of the measured profile. (ORIGINAL)
  Maximum urethral closure pressure (MUCP) is the maximum difference between the urethral pressure and the intravesical pressure. (ORIGINAL)
  Functional profile length is the length of the urethra along which the urethral pressure exceeds intravesical pressure in women.
  Pressure “transmission” ratio is the increment in urethral pressure on stress as a percentage of the simultaneously recorded increment in intravesical pressure.
  Abnormal leak point pressure is the intravesical pressure at which urine leakage occurs due to increased abdominal pressure in the absence of a detrusor contraction.  (NEW) 

The Leak Pressure Point should be qualified according to the site of pressure measurement (rectal, vaginal or intravesical) and the method by which pressure is generated (cough or valsalva). Leak point pressures may be calculated in three ways from the three different baseline values which are in common use: zero (the true zero of intravesical pressure), the value of pves measured at zero bladder volume, or the value of pves immediately before the cough or valsalva (usually at 200 or 300ml bladder capacity). The baseline used, and the baseline pressure, should be specified.
Detrusor leak point pressure is defined as the lowest detrusor pressure at which urine leakage occurs in the absence of either a detrusor contraction or increased abdominal pressure. (NEW)  
Detrusor leak point pressure has been used most frequently to predict upper tract problems in neurological patients with reduced bladder compliance. ICS has defined it “in the absence of a detrusor contraction” although others will measure DLPP during involuntary detrusor contractions.
Voiding studies
assess detrusor contractility and urethral obstruction
During voiding the detrusor may be
acontractile one that cannot be demonstrated to contract during urodynamics
areflexic acontractility due to an abnormality of nervous control
underactive a detrusor contraction of inadequate magnitude and/or duration to effect bladder emptying
normal voluntarily initiated contraction that is sustained and can usually be suppressed voluntarily
During voiding the Urethra may be
  mechanical  stricture 
bladder outlet obstruction
detrusor/ (external) sphincter dyssynergia - typically need radiology or e.m.g. to support diagnosis of dyssynergia
To see my old standardisation page ICS.HTM