Summary Of Evidence

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Analysis of Evidence

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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.