Wichita Mountain
Neurosurgery
&
Spine David M. Pagnanelli, M.D.
Normal
Pressure Hydrocephalus
All
of our brains have cavities in them, called ventricles. In the cavities,
the brain produces a fluid, called cerebrospinal fluid ( CSF). The CSF
is constantly being produced, circulates through and around the brain,
and is then absorbed into the circulation. Every
day, the body makes about 8 oz. of CSF, and about the same amount of
fluid is reabsorbed into the bloodstream. A build up of
the CFS, caused either by over production or blockage in its circulation
produces a problem called Hydrocephalus, or, water on the brain. There
are several types of hydrocephalus. Normal Pressure Hydrocephalus(NPH)
is the type most commonly found in the elderly population.
In NPH, there is a disturbance in the
absorption of CSF. This causes the ventricles to enlarge, putting pressure
on the brain. It may result from a brain hemorrhage, head trauma, infection,
tumor, or complications of surgery. However, many people develop NPH
even when none of these factors are present. In these cases the cause
of the disorder is unknown.
Symptoms of NPH include progressive
mental impairment and dementia, problems with walking, and impaired
bladder control leading to urinary frequency and/or incontinence. The
person also may have a general slowing of movements or may complain
that his or her feet feel "stuck." Because these symptoms are similar
to those of other disorders such as Alzheimer's disease, Parkinson's
disease, and Creutzfeldt-Jakob disease, the disorder is often misdiagnosed.
Many cases go unrecognized and are never treated.
Dementia will include short -term
memory loss, forgetfulness and difficulty in dealing with everyday tasks.
Because these symptoms appear gradually and are commonly associated
with old age, many people think they are normal and assume they must
learn to live with their problems. Mobility problems may include a shuffling
or wide based gait, which could result in frequent falls. Urinary incontinence
is usually the last symptom to appear, often starting when someone has
difficulty in getting to the toilet in time.
One quarter million Americans with
some of the same symptoms as dementia, Alzheimer's, or Parkinson's may
actually have NPH.
How is NPH diagnosed?
There is no specific test to confirm the diagnosis of NPH.
However we have tests that will help in diagnosis, in conjunction with the
history and physical exam. The tests that I prefer are:
Computed tomography (CT)
A CT
scan is a diagnostic tool that uses X-rays and a computer to create
pictures of structures inside the body. A
CT
scan can provide images that show the size of the ventricles.
Lumbar puncture for NPH Also called a spinal tap,
this procedure is used to remove a sample of the CSF. For NPH, this
test is used to determine if a persons symptoms improve after removing
a large amount of fluid. About 1 to 1½ oz. of fluid is removed.
However, this test is not definitive.
Magnetic resonance imaging (MRI) An MRI scan uses a magnet and radio
waves, instead of X-rays, to produce images. This test provides some
basic characteristics of NPH.
Continuous CSF drainage This
is the most reliable test that we have. It involves draining CSF from
a spinal catheter for 2-3 days. The patient is then observed for signs
of improvement. Complications of the drain include headache, hemorrhage,
and infection.
How is NPH Treated?
Treatment is usually by surgery. A fine tube and valve
(called a shunt) is inserted into one of the cavities of the brain to drain
away excess fluid. The fluid is diverted to another part of the body (usually
the abdomen), where it is reabsorbed into the bloodstream.
Expectations (prognosis)
Prognosis is poor without medical and surgical intervention.
Symptoms progress and the disorder results in death.
Surgical treatment improves symptoms in about 60% of cases,
with the best prognosis (probable outcome) for those with minimal symptoms.
Those patients with sever dementia, are less likely to get a good response from
shunting.
The drain is placed with local anesthesia, but sedation can
be used, if needed. The patient is placed in the lateral position, the back
numbed with Xylocaine and needle passed into the fluid sac at the lower spine.
A catheter is threaded in to the sac and connected to a sterile drainage bag.
We will then, periodically drain CFS into the bag for the next 2-3 days. It is
important for family and friends to observe the patient for any signs of
improvement throughout this time.
The patient will probably get a headache from the drainage,
so we will have to regulate the amount of CFS drained to keep them as
comfortable as possible, but still be able to do the test.
Shunt Surgery
This
procedure is performed in the operating room under general anesthesia.
It requires two or three incision for exposure. The first incision is
above and behind the ear (usually the right side). A small opening is
made in the bone, and a thin hollow catheter passed into the ventricle.
This is then attached to the shunt valve, which in turn is attached
to another piece of tubing. This later piece of tubing is tunneled under
the skin to the abdomen, and passed into the abdomen through another
small incision. In some cases, an addition small incision is needed
at the skin of the chest, for passage of tunneling process.
The
pump valve that I use is programmable. This means
that I can regulate the amount of fluid
flowing through it. The adjustments are made using
a magnet and a small computer. This is done in a completely
painless manner through the skin.
Expectations
If the patient has fit the criteria listed
above, by history, physical exam, imaging studies, and continuous spinal
fluid drainage, then they have roughly a 60% chance of long term improvement
with a shunt.
I
drain the fluid slowly, to give the patients brain time to adjust to the
implanted drainage system. In spite of this, some patients have an adverse
reaction to shunting. In fact, they may even get worse for a while afterwards.
Main Complications
Infection, hemorrhage, malplacement of the shunt catheter,
over drainage. These are uncommon and usually require only some adjustment of
the system. However, in some instances, these can be severe and require further
surgery.
Care of the Shunt
No care of the shunt is required. Either me, or my staff,
are the only ones that should be adjusting the shunt.
After the Shunt
Some patients become more confused after shunting, and
require a few weeks to adjust to the system.
Links:
Guardians of Hydrocephalus Research Foundation
2618 Avenue Z
Brooklyn, NY 11235-2023
GHRF2618@aol.com
http://ghrf.Homestead.com/ghrf.html
Tel: 718-743-GHRF (4473)
Fax: 718-743-1171
Hydrocephalus Association
870 Market Street
Suite 705
San Francisco, CA 94102
info@hydroassoc.org
http://www.hydroassoc.org
Tel: 415-732-7040 888-598-3789
Fax: 415-732-7044
Hydrocephalus Support Group, Inc.
P.O. Box 4236
Chesterfield, MO 63006-4236
hydrodb@earthlink.net
Tel: 636-532-8228
National Hydrocephalus Foundation
12413 Centralia Road
Lakewood, CA 90715-1623
hydrobrat@earthlink.net
http://nhfonline.org
Tel: 562-402-3523 888-857-3434
Fax: 562-924-6666
About Surgery
Cervical (Neck)
