**Abstract:**  
  
Urodynamic studies have become an increasingly important part of the
evaluation of voiding dysfunction. Cystometrogram, uroflowmetry, urethral
pressure profile, sphincter electromyogram, stimulus-evoked response, and
voiding pressure studies are used to identify abnormal voiding patterns in
symptomatic patients with disorders of urinary flow. Each of the urodynamic
studies has benefits and limitations that must be respected for each specific
clinical application.  
  
**Cystometrogram, simple/complex**  
is used to evaluate detrusor contractions and abnormalities of bladder
compliance, to measure post-voiding residual, to determine bladder capacity
and to detect DSD (detrusor sphincter dyssynergia). Normal results are
expected in stress incontinence.  
Complex cystometrogram involves the use of calibrated electronic equipment to
measure intra-abdominal, total bladder, and true detrusor pressures
simultaneously. Its purpose is to differentiate an involuntary detrusor
contraction or reversed bladder compliance from an increase in intra-abdominal
pressure. False positives may be a problem, especially in the elderly.  
  
 **Uroflowmetry, simple/complex**  
measures the urine flow rate visually, electronically or with the use of a
disposable unit. The flow rate reflects the combined activity of the detrusor
muscle, bladder neck, and urethral function. Decreased flow rate may be due to
poor detrusor function from, for example, neurologic lesions, obstructing BPH,
or cystocele. Increased flow rate may indicate poor urethral function causing,
for example, stress urinary incontinence (SUI) or intrinsic sphincter
dysfunction (ISD).  
  
 **Urethral pressure profile studies**  
measure resting and dynamic pressures along the length of the urethra
responsible for maintaining continence. This test has limited applications,
e.g. artificial urinary sphincter. Urethral pressure studies should be
reserved for those patients in whom other tests are inconclusive. The test is
performed to rule out severe urethral incompetence.  
  
 **Stimulus Evoked Response**  
has a limited application in practical urology but can be used to evaluate
cases of suspected cauda equina syndrome.  
  
 **Voiding Pressure Studies (VP)   **  
can measure detrusor contractility and detect outlet pressure obstruction if
the patient is able to void. Simultaneous measurement of detrusor and urethral
pressures during voiding is especially helpful in diagnosing urodynamic
obstruction.  
  
 **Intra-abdominal Voiding Pressure (AP)**  
can contribute to the evaluation of true detrusor muscle function by
accounting for any component of intra-abdominal pressure in the bladder
pressure voiding curve.  
  
 **Indications:**  
  
Urodynamic studies are indicated only after an initial evaluation is performed
that at minimum includes an appropriate history, physical exam, and urinalysis
with microscopy. Infection, if present, should be treated and effectiveness of
treatment observed before further diagnostic (urodynamic) testing or other
therapeutic interventions are undertaken.  
  
Urodynamic testing is covered under Medicare when medically necessary to
assist in the diagnosis of urologic dysfunction and when any of the following
apply:

  1. Uncertain diagnosis and inability to develop an appropriate treatment plan based on the basic diagnostic evaluation above.
  2. Failure to respond to an adequate therapeutic trial.
  3. Consideration of urologic surgical intervention, particularly if previous surgery failed or if the patient is a high surgical risk.
  4. Presence of other comorbid conditions such as incontinence associated with recurrent symptomatic urinary tract infection, persistent symptoms of difficult bladder emptying, history of previous anti-incontinence surgery or radical pelvic surgery, beyond hymen and symptomatic pelvic prolapse, prostate nodule, asymmetry or other suspicion of prostate cancer, abnormal post-void-residual urinalysis, and neurologic conditions affecting voiding function such as multiple sclerosis and spinal cord lesions or injury.

Manometric studies may be medically necessary when performed for
reconstruction of the ureter or obstruction of the ureter.  
  
**Limitations:**

  1. Testing must be restricted to only those urodynamic testing procedures which are necessary to differentiate the etiology of the voiding dysfunction and must not consist of an entire battery of tests applied routinely to all patients.
  2. Payment for these procedures is predicated on the presence of signs and symptoms of voiding dysfunction that must be clearly documented in the medical record.
  3. The tests performed must be appropriate to analyze the patient's signs and symptoms or to guide further medical and/or surgical decision-making.
  4. The use of any of these procedures in a screening capacity does not represent a payable service.
  5. Pelvic descensus syndromes without urinary symptoms do not qualify for urodynamic testing.

Urinary flow rates determined by the patient at home and recorded for
physician evaluation are not eligible for Medicare reimbursement.