Urodynamics Explaination

This key is intended to help explain our UDS (Urodynamic Study) and its terminology.

It is not intended as a substitute for your clinical judgment.

• Bladder Capacity: Normal Bladder Capacity is 300 ml to 600 ml.

• Empties Completely: Less than 100 ml left in the bladder after a void (based on a normal capacity void).

• Incomplete Emptying:  May be caused by an outlet obstruction or minimal/absence of a detrusor (bladder) contraction. Treatments include pelvic floor muscle rehabilitation using biofeedback, behavioral modifications, clean intermittent catheterization, medication and surgery. Can offer routine office PVR (Post Void Residual) checks.

• Straining to Void- Patients voiding with straining, if treated with surgical intervention for stress incontinence, are at greater risk for urinary retention or incomplete emptying after surgery. When patients are straining to urinate on an uroflow test we might state “flow pattern may be indicative of a voiding dysfunction.”

• Filling Sensations: Is truly subjective and therefore requires an alert patient and good communication with the person performing the test. Hyper or Diminished/Delayed Sensation could be indicative of a neurological disorder. Managing Hyper or Diminished/Delayed sensation can be achieved with timed voiding.

• See Filling Sensation:  Drawing your attention to the filling sensations listed below as they may be a mixture (i.e.: delayed and hyper sensation).

• Urodynamic Stress Incontinence:  This documents the lowest leak point pressure (LPP) a patient leaks urine. May be demonstrated with coughs or valsalva. Stress incontinence may be treated with behavioral modifications, pelvic floor muscle rehabilitation using biofeedback, or surgery. Low LPP under 100 cmH20 or low Urethral closure pressure on UPP (urethral pressure profile) may need additional treatments such as surgery and/or bulking agents.

• Stable Detrusor: Detrusor (Bladder) stability during filling. This is normal. The bladder should relax to accommodate fluid.

• Phasic Detrusor Overactivity (Urgency or Urge Incontinence):  Bladder (detrusor) begins to have an uninhibited contraction and then relaxes with or without outflow of urine. Urine output usually minimal.

• Terminal Detrusor Overactivity (Urge Incontinence): Involuntary detrusor (bladder) contractions with outflow of urine.

• Detrusor Overactivity (Unstable Detrusor): Can be treated with anticholinergic (bladder)medications , behavioral modification, electrical stimulation, pelvic floor muscle rehabilitation using biofeedback and Urgent PC. In severe cases, Interstim may be appropriate or Botox injections.

• Normal Bladder Compliance: This is normal. Bladder (Detrusor) muscle relaxes to accommodate the filling of the bladder.  

• Low Bladder Compliance: May be indicative of i.e. Interstitial Cystitis (IC) or Detrusor (bladder) Trabeculation.
  

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