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Director of the Center for Urogynecology of Saint Barnabas
Medical Center
is the first women’s health specialty
devoted to the treatment of the following pelvic floor disorders:
urinary and fecal incontinence or loss of bladder or bowel
control, overactive bladder defined by urinary urgency
or difficulty holding back a full bladder, pelvic organ
prolapse or the descent of pelvic organs such as a dropped
uterus, bladder, vagina or rectum, voiding or defecatory
dysfunction or difficulty urinating or moving bowels and pelvic or bladder pain involving discomfort, burning or other
uncomfortable pelvic symptoms, including bladder or urethral
pain.
The bladder is often described as an “unreliable witness” because
often times it is difficult to differentiate the various types
of urinary incontinence or urinary leakage based exclusively
on a patient’s symptoms. Symptoms of overactive bladder
may overlap with symptoms of stress incontinence (involuntary
urine leakage usually associated with laughing, coughing,
sneezing or heavy lifting).
Urodynamic studies are a series of office tests that are
useful in observing the function of the lower urinary tract,
which consists of the bladder (a muscular organ that stores
urine) and the urethra (the tube from which urine is eliminated
from the body). These tests can evaluate storage abnormalities
of the lower urinary tract. These include overactive bladder
and stress urinary incontinence as well as voiding dysfunction
or emptying abnormalities, which may be associated with a
feeling of incomplete bladder emptying, the need to strain
to empty the bladder, hesitancy or weak urinary flow.
Urodynamic studies can help differentiate the etiology (all
of the causes) of these symptoms, providing a better understanding
of lower urinary tract function. Currently there is no consensus
regarding which patients require a urodynamic study. Among
other indications, urodynamics may be recommended for the
following:
- Patients with voiding (bladder emptying) difficulty
- Patients
who are suspected of having a neuropathy or neurologic condition
that is causing lower urinary tract symptoms
- Patients with
previous failed nonsurgical or surgical therapy
- Patients for
whom invasive or surgical treatments are being considered
A
urodynamic study usually takes about 30 minutes to perform,
but patients should be prepared to spend up to an hour in
the office. The study consists of a combination of different
tests which are described below.
– This is a simple and noninvasive
test in which the patient is asked to empty her bladder in
a special commode that records the flow rate and volume of
urine. The volume of urine remaining in the bladder is then
measured. Uroflowmetry is a useful screening test to evaluate
a patient for bladder emptying abnormalities.
– During this study a small
catheter (soft tube) is placed in the bladder and another
in either the vagina or rectum, and the bladder is then filled
with sterile water or saline. Placement of the catheters involves
minimal discomfort as well as a small risk for the development
of a
bladder infection. As the bladder is being filled with water
the patient is asked to report her first sensation of having
to empty the bladder followed by a strong desire and urinary
urgency. The goal is to try to reproduce similar symptoms
that the patient has at home. The pressure and volume relationships
of the bladder are measured, including bladder capacity and
compliance, bladder muscle activity and sensation.
– Two tests can
be performed to evaluate the severity or type of stress urinary
incontinence, a leak point pressure and urethral pressure
profilometry. A leak point pressure is performed by having
the patient bear down or strain during various times of the
subtracted cystometry and measuring the pressure at which
urinary leakage occurs. Urethral pressure profilometry is
a graphic representation of pressure within the urethra at
successive points along its length. Traditionally, these tests
have been useful in deciding on the appropriate treatment
for patients with stress urinary incontinence.
– During this part of the study,
the patient is asked to empty her bladder around the catheters
that had been placed during the subtracted cystometry. The
purpose is to document objectively the mechanism of abnormal
bladder emptying. It is very similar to uroflowmetry, except
that the bladder is emptied with the pressure catheter in
the bladder and vagina or rectum.
– The urodynamic study is performed
with electrode patches that are placed near the rectum in
order to assess the muscles that control urination.
In conclusion, urodynamic studies are important because
a patient’s symptoms do not always accurately reflect
the physiologic state of the bladder. The goal of urodynamic
tests is to reproduce a patient’s symptoms while observing
the changing function of the lower urinary tract during that
time. It can be very useful in determining the cause of symptoms
and in assessing the severity of stress urinary incontinence.
Urodynamic studies provide some level of objectivity and should
be used in conjunction with a patient’s clinical history
in selecting the appropriate therapy.
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