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The history of brain surgery
Brain surgery is perhaps the oldest of all practiced medical arts. The
remains of successful brain operations were found in France circa 7000
BC, and the success rate was remarkable even then. There is evidence of
brain surgery as early as 3000 BC in Africa. Historical records show that
surgery of the brain was practiced by Hippocrates in Greece, in the Roman
times, and by Medieval surgeons in the Arab world, well until the 18th
century. Hippocrates, the father of modern medical ethics, left many texts
on brain surgery. Back in those times, surgeons didn't know about the
function of the brain.
The road to scientific neurosurgery first began in the 19th century
with the discovery that certain parts of the brain control temper, mood
and intellect. One clinical case was fundamental in the discovery of the
brain's functionality: a railroad construction supervisor received an
extensive lesion of the frontal part of his brain when a steel rod traversed
his skull. The injury then led to profound changes in his mood and character.
This was the first time the connection between the brain and human behavior
was recognized.
Since the first scientific operations, the medical devices and techniques
used for neurosurgery have been continuously improving. Today, many different
diseases can be treated by neurosurgical techniques.
When treating brain tumors, tumor resection (tumor removal by operation)
is still a common treatment. Until recently, open neurosurgery meant a
fairly high risk for patients in terms of damaging important structures
of the brain. Today, computer-based neuronavigation or image-guided surgery
assists the surgeon during all phases of the operation. This allows the
surgeon to keep the operation minimally invasive and to avoid critical
structures of the brain. Thus, the risks of paralysis or other impairments
after surgery are minimized and recovery time is considerably reduced.
What is image-guided surgery?
Image-guided surgery has been employed in neurosurgery since the mid-1990s.
This new technique relies on a powerful computer system, which assists
the surgeon in precisely localizing a lesion, in planning each step of
the procedure via a 3D model on the computer screen, and in calculating
the ideal access to the tumor before the operation. The tumor and its
surroundings can be viewed from different angles and in relation to landmark
structures, such as the optic nerve or the brain stem. During the operating
procedure, the movement of the instruments in use inside the brain can
be tracked on the monitor with a precision of 1-2 millimeters, through
which damage to healthy tissue and to critical areas can be avoided as
much as possible.
What is VectorVision®?
VectorVision® is the state-of-the-art image-guided surgery system
used for the resection of brain tumors, as well as for other neurosurgical
applications. While conventional x-ray images depict tumors in two dimensions,
VectorVision® provides the third dimension - depth - creating a three-dimensional
image of the head and brain. This is particularly useful in reaching a
tumor located deep within brain areas traditionally considered to be difficult
to reach.
Thanks to pre-operative planning with VectorVision®, the procedure can
be simulated on the computer: the surgeon can map out the surgical procedure
ahead of time and can identify the best access to the tumor. The tumor's
location and its position relative to the sensitive structures in the
brain will be pinpointed so that sensitive structures can be avoided and
the incision can be kept as small as possible. During the procedure, VectorVision®
tracks instrument movement with an extremely high precision, providing
the surgeon with total control inside the brain at all times using "real-time"
imaging. The surgeon can also check if the tumor has been removed as planned.
This improves the prognosis of the patient.
What types of surgery can be performed image-guided?
Stereotactic Biopsy
A stereotactic biopsy is performed in order to obtain an exact diagnosis
of the tumor and to differentiate the tumor from healthy tissue or necrotic
tissue. A small tissue sample is obtained from a defined region of the
brain by using a long and very thin needle, which is passed through a
skin puncture and tiny opening in the bone to the location of the tumor.
The tissue sample is then examined by a pathologist and the nature of
the lesion is determined. If the lesion proves to be a tumor, the type
of tumor will be determined. The image-guided surgery system assures that
the tissue sample is taken from the area of interest and not accidentally
from the neighbouring region. It also helps in the pre-operative procedural
planning, as well as in the avoidance of critical structures. A biopsy
can be performed as part of the surgery to remove the tumor, or as a separate
procedure. The risks of this procedure are low, including a less than
1% chance for significant hemmorrhage. Most patients are able to leave
the hospital after a 24-hour stay.
Craniotomy
The most commonly performed surgery for the removal of a brain tumor is
called a craniotomy. A craniotomy is performed to rid the patient of the
tumor or to halt its progress. The objective of the surgery is to excise
as much of the tumor as possible. Even if only a portion of the tumor
can be removed, this can still lead to an improvement of symptoms. In
most cases, the remaining tumor has to be treated by other methods. For
the surgery, a portion of the scalp is usually shaved, and an incision
is made through the skin. A piece of bone is removed to expose the area
of brain over the tumor, then the tumor is removed. After the tumor has
been removed, the bone is generally replaced and the incision closed.
In a conventional craniotomy, surgeons guide themselves by what they
can see, their knowledge of anatomy and their interpretation of the pre-operative
scans. The greatest application of the image- guided surgery system is
in anatomic navigation around tumor margins and determining regional anatomy.
With the use of VectorVision®, the tumor, as well as different brain
structures, can be well identified and viewed on the computer screen.
The surgeon can navigate precisely to the tumor while avoiding sensible
structures. The depth of the tumor can be mapped, as well as critical
structures that might lie on the other side of the resection plane. Such
navigation increases the precision of the procedure, and can increase
the speed at which surgery can be performed.
Shunt
Occasionally, patients with brain tumors develop increased intracranial
pressure. To relieve the pressure, a shunt procedure to drain excess or
blocked fluid might be necessary. When compared to other brain tumor surgery,
the surgery to implant a shunt is relatively minor: a small hole is drilled
in the skull through which a catheter - a narrow piece of flexible tubing
- is inserted into a ventricle of the brain. The other end of the tubing
is threaded to another body cavity where the fluid is drained and absorbed.
A small incision is necessary at the body cavity to which the catheter
is threaded (abdomen or chest). Shunts might be temporarily left in a
position until the brain tumor has been surgically removed; yet in some
cases, they may be permanent.
Image-guided surgery assures that the shunt can be accurately placed
in the ventricle to reduce the intracranial pressure. Even with patients,
in whom the build-up of fluid has lead to anatomical changes inside the
brain, the procedure can still be safely performed. In most patients,
the symptoms of increased intracranial pressure cease a couple of days
after the operation, in other patients it may take up to a couple of weeks.
If the symptoms reappear, a doctor should be consulted, as the catheter
may be blocked or dislocated. Under certain circumstances, a second surgery
may become necessary. Other complications, such as bacterial infections
may also occur.
Implants
In many cases, patients with brain tumors are treated by the insertion
of radioactive material (brachytherapy) or genetic material into the cavity
left by the tumor's removal. VectorVision® is able to ensure the accurate
placement of an implant into the defined area.
Functional Neurosurgery
The scans taken before surgery yield a great deal of information; however,
they don't always provide the precision needed to avoid critical areas
of the brain during surgery. Mapping tools can improve the safety and
effectiveness of surgery by locating the exact areas of the brain responsible
for speech, comprehension, sensation or movement. Specific areas of the
brain are stimulated by a tiny electrical current, through which their
functionality can be determined. This allows these areas to be avoided
during surgery.
What are the side effects and complications of brain surgery?
The risk of side effects largely depends on the type of neurosurgical
procedure performed. Some operations have higher risks than others, and
for some the risk is lower. Please talk to your physician or neurosurgeon
to find out what kind of side effects might occur in your individual case.
An example of a difficult operation is that of the large acoustic neuroma.
There is a serious risk of hearing loss and/or facial function on one
side of the face. A shunt operation also carries the risk that the shunt
may not be working properly following the operation. This means that an
additional surgery may be necessary.
What can you expect as a patient?
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Step 1 - Marker Attachment and Diagnostic Imaging
On the day of surgery or the day before the surgery, special adhesive
markers will be attached to certain areas of your head. These markers
are visible in the CT or MRI scan and will stay placed while the diagnostic
images are taken. Later, when you are in the operating room, these
markers are seen by the cameras of the VectorVision® navigation
system and are used to pinpoint your exact position in the operating
room. This procedure is not painful. The attachment of the markers,
along with the diagnostic imaging, only take about 45 minutes. |
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Step 2 - Treatment Planning
Following imaging, the data obtained from the CT/MRI is transferred
to the VectorVision® planning station. The computer calculates
a 3-D image of your head, based on the CT/MRI scan. A strategic plan
for the optimal surgical approach can then be developed by your surgeon.
Based on the information provided by the computer, your surgeon will
plan the surgery in such a way as to avoid vital structures within
the brain, and keep the surgical interference as small as possible.
While you are being prepared for the operation and the general anesthesia
is being applied, the plan is transferred to the neuronavigation system
in the operating room. |
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Step 3 - Surgery
After you have received general anesthesia, your head will be securely
fixed to the operating table in order to avoid a shifting of your
head. The cameras of the VectorVision® system track the exact
position of your head as well as that of the surgeon's instruments.
The monitor allows the surgeon to survey the entire procedure in real-time,
and to view the brain and the tumor, as well as the instruments from
different angles and viewpoints. The surgeon can then safely navigate
towards the tumor. |
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Step 4 - Post-operative
After the tumor resection is complete, the bone and skin flap are
closed and you will be brought to the recovery room. In most cases,
the surgical procedure will take about 4-5 hours. Treatment time may
vary considerably depending on the type of surgical procedure. |
For more information, contact:
Fred J. Epstein, MD
Director of the Institute for Neurology and Neurosurgery (INN)
Beth Israel North Medical Center
170 East End Avenue
New York 10128
(212) 870-9600
or visit www.brainlab.com
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