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Procedure
description
A craniotomy
for epilepsy is performed in an attempt to remove the portion
of the brain which is "irritating" to the brain
and causing seizures. This surgery my involve removing
a portion of the brain, such as the temporal lobe, or it may
involve dividing a route by which seizures migrate through
the brain, as in section of the corpus callosum (connects
both hemispheres of the brain). The surgeon and epileptologist
(neurologist specializing in the study of epilepsy) will take
into account vital portions of the brain in the region of
the intended removal, and may perform electrical mapping studies
of the area by the use of electrode grids placed during a
previous surgery, or the surgery may be done with the patient
awake. Some areas of the brain are relatively silent,
while others are eloquent (injury to these areas would result
in noticeable changes in day to day performance). For
example, the left temporal lobe is "dominant" in
96% of right handed people. This means that in these
patients, removal of the temporal lobe of the brain would
result in a dysphasia (difficulty with speech and comprehension).
On the other hand, removal of the right temporal lobe in these
patients may not result in any noticeable change at all.
In addition, regarding the left temporal lobe, in many patients,
the first 5 cm of the lobe are relatively silent, and removal
of this portion may not result in a noticeable deficit.
Of course, there is no line in the brain telling the surgeon
where to cut, and the amount of brain which can be safely
removed is determined by the functional monitoring.
This can be accomplished in two ways. Electrical grids
may be placed over the brain, and while the patient is awake
in a monitoring unit postoperatively, function of the brain
can be mapped to location by stimulating the grid. Or,
alternatively, the surgery may be done with the patient awake,
stimulating portions of the brain intraoperatively .
The patient will be taken to the operating room and put to
sleep under general anesthesia. The head will be partially
shaved, to expose the area of the operation. The head
is then placed in three fixation points (Mayfield head pins).
This provides the ability to keep the head perfectly still
during the procedure. The surgeon may register a navigational
device which allows the use of "real time" intraoperative
navigation. The area where surgery is to be performed
is then "prepped and draped" using an antibiotic
solution. Next, the surgeon will make an incision, and
reflect the scalp over the area of the tumor. An air
powered drill is then used to make a hole in the skull, and
a "footplate attachment" on the drill, or another
similar device, is used to cut open a flap of skull.
The dura mater (tough covering of the brain) is then opened.
An operating microscope is generally brought into the field,
and the surgeon will approach the intended area within
the brain. Intraoperative mapping while awakening the
patient may or may not be performed. If a grid of electrodes
had already been placed several days earlier (during another
surgical procedure), then the area of intended brain removal
is known. The portion of the brain responsible
for irritating the brain and causing seizures will be removed,
or a tract or bundle of fibers necessary for spreading a seizure
to the rest of the brain will be divided. Any
visible bleeding points will be cauterized. Often, hemostasis
promoting material is gently laid over the surfaces of the
brain, and closure is begun. The surgeon will
close the dura, and approximate the skull using titanium plates
or another device to hold the bone together. Next the
scalp will be closed in layers, and a pressure monitor may
be placed into the brain to allow the postoperative monitoring
of pressure within the brain.
Procedure
Risks
Risks
for craniotomy for epilepsy can be broken down into two categories,
1) those related to the operative site, and 2) those related
to the risks of anesthesia.
Risks
related to the operative site:
Surgical
Exposure: The patient is placed in a position so as
to allow the surgeon good access to the tumor. Insicions
in the scalp may range from small to quite large.
There is risk of non healing of the scalp or bone post operatively.
Although very uncommon, there can be injury to or tearing
of the scalp from the pins on the Mayfield clamp.
The plates used to close the skull could erode through the
skin after the wound has heeled.
Brain
injury: The surgery involves opening of the surface
of the brain, and may involve going into the deep structures
of the brain. With surgery on the temporal lobe, there
is risk of difficulty with understanding and speaking or
expressing oneself. There may be cognitive or personality
changes. There may also be injury to vision, and a portion
of the visual field may be lost. If the surgery is located
near the deep structures of the brain, there can be injury
to strength of the upper or lower extremities. If the surgery
is located near the sagittal sinus (a large vein draining
both hemispheres of the brain), as in the procedure for
division of the corpus callosum, there is a risk to this
vein of either injury or thrombosis (clotting off).
If the vein is injured, large amounts of blood could be
lost during the surgery. If the vein clots off, this
could result in brain swelling and death. There is the possibility
that there may be injury to the brain. If so, this
could result in weakness, seizures, stroke, paralysis, coma
or death. There may be residual fluid or blood, requiring
additional surgery in the future.
General
Risks: These include such general difficulties as bleeding,
infection, stroke, paralysis, coma and death. Incisions
on the scalp generally heal well, but could become tender,
numb, or may heal in an unpleasant manner. There is also
the possibility that the surgery may not relieve the symptoms
for which the procedure was performed, and seizures may
persist. In addition, although every attempt is made to
protect all areas of the body from pressure on nerves, skin
and bones, injuries to these areas can occur, particularly
with prolonged cases.
Risks
of Anesthesia: Blood clots in the legs, heart attacks,
reaction to the anesthetic, reaction to blood transfusion,
if given
Post-operative
care:
There
is surprisingly relatively little pain associated with craniotomies.
Your surgeon will prescribe pain medications for any pain
associated with the incision.
- Immediately
upon discharge, contact our office and set up an appointment
for staple removal if one has not already been made.
- Take
it easy until seen by the physician. This does not
mean bed rest, but athletic activities during this period
are definitely not recommended. Please give your
incision a chance to heal. Avoid any type of activity
which might risk a blow to the head.
- You
may resume activity as your body permits, but avoid extremes.
For example, walking is fine, but avoid any strenuous
running. USE GOOD JUDGMENT AND COMMON SENSE.
If you have a question, ask your doctor.
- No
driving until cleared with your surgeon. A driving
test may be required, at the discretion of your surgeon.
Even though you may feel fine, your peripheral vision
and reflexes may have been affected, and we want you to
be safe on the road for yourself as well as for others.
- You
may shower after you go home unless otherwise instructed.
Cover the incision with plastic wrap before the shower
and remove it afterward. Change dressing immediately.
You may shower without covering the incision one week
after the staples are out. Follow instructions concerning
care of tapestrips, stitches or staples. Your surgeon
or nurse clinician will explain the techniques used
in the closure of your incision.
- Sexual
activities are permitted.
- If
you notice swelling, redness or opening of the incision,
or if there is any clear fluid draining from it, please
contact your surgeon immediately! If you develop
a fever, stiff neck or chills, contact the office immediately.
Take your temperature at 4:00 PM daily until the clips
are removed. Call if greater than 101 degrees Fahrenheit.
-
If you have a seizure, notify our office or come to the
emergency room.
- If
you develop any new weakness, notify our office.
-
If you have any paralysis or weakness, post-operative
care will need to be tailored to this. If a brace
for an arm of a leg has been prescribed, use it as recommended
by your surgeon.
- If
you have any questions, call our office, and for after
hours emergencies, call the medical society.
- Take
your medications prescribed on discharge, as directed.
Your physicians will direct you as to which seizure medications
to take.
- Do
not take any medications which will "thin the blood"
such as coumadin or aspirin, or other non-steroidal antiinflammatory
medications, unless otherwise advised by your physicians.
- Make
sure to follow up with any other physicians involved in
your care. These may include your family physician
and neurologist.
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