Neurosurgery is the operative therapy of the central and peripheral nervous
system. For brain tumors, neurosurgery is brain surgery and is the operative
removal of brain tumors. Neurosurgery or brain surgery for brain tumors is a
very diverse field. The determinants of neurosurgery for brain tumors include
the type of brain tumor, size of the brain tumor, location of the brain tumor
in the brain, the symptoms caused by the brain tumor, and the neurological
deficit caused by the brain tumor.
Neurosurgery is the operative surgery on the brain or peripheral nerves. For
neurosurgery (brain surgery) the neurological capacities of the patient
(thought, memory, personality, reading, writing, walking) are the primary
concerns for preservation. The neurological status of the patient is the basis
for determining when to perform neurosurgery and for evaluation of the patient after
neurosurgery.
During Neurosurgery how is the brain opened for removal of a tumor?
For Neurosurgery, the brain tumor is approached in sequential steps starting from the outside
and working inwards. First, the patient is given general anesthesia. The scalp
is then shaved and the skin is prepared using special soap. The scalp is
"infiltrated" with local anesthetic containing epinephrine to reduce bleeding.
The scalp is cut with a scalpel above the location of the path to the tumor.
The scalp is retracted. The skull is opened using a special high speed,
air-driven saw. The "bone flap" is removed and kept in sterile saline until
time to replace it during closing. Once the portion of the skull is removed,
the "dura" is visible. The "dura" or fibrous covering of the brain, is opened
using a small, narrow scalpel. The opening of the dura usually corresponds to
the outline of the opening formed by removal of the skull. The opening of the
dura allows exposure of the underlying brain. This exposes the surface of the
brain. The brain is either "retracted" (lifted out of the way) or incised (cut)
to make a path to the brain tumor.
During Neurosurgery how does the surgeon remove only the tumor and not hurt the
brain?
The path to the tumor is chosen long before Neurosurgery. The positioning of the
patient allows the correct trajectory to the tumor during Neurosurgery. The path that will result
in least damage is chosen. The path may involve retraction or lifting of brain
rather than cutting the brain. For transcortical openings, a small portion of
the cortex (gyrus) is coagulated using the bipolar coagulator. A #14 blade
scalpel allows opening the cortex. The brain is gently entered using gentle
suction and retraction by flat, smooth retractors. Once the tumor is
visualized, its removal can begin. The initial approach to the brain tumor can
take several hours, depending on the location (less for superficial brain
tumors near surface, more for "deep" brain tumors near center of the brain).
The neurosurgeon often uses the operative microscope to carefully view the
brain tumor and the surrounding normal brain at this stage. Using visual
magnification, the brain tumor is first "biopsied" (small piece taken for
"frozen section") if no biopsy was taken before. This tells the neurosurgeon,
in the operating room, the type of brain tumor with which he is dealing, and
guides the aggressiveness of the resection.
The brain is gently retracted away from the brain tumor during removal. To
minimize retraction and pressure on the brain, the central portion of the brain
tumor is removed, allowing the remainder of the brain tumor to fold in on the
cavity, thereby reducing pressure on the normal brain. This prevents pressure
on the brain.
During Neurosurgery how can the brain tolerate surgery inside it?
The brain can tolerate Neurosurgery inside it. The goal of Neurosurgery for
brain tumor is preservation of the normal brain and removal of the brain tumor.
The normal brain is only gently retracted away from the brain tumor during
Neurosurgery, thus preventing injury to the normal brain tissue. In cases where the
normal brain tissue is cut in order to reach the brain tumor, a path to the
brain tumor is selected that involves "silent" regions of the normal brain
(regions that can be traversed or even sometimes removed without subsequent
neurological deficit).
Why is Neurosurgery sometimes the best treatment for brain tumors?
Immediacy
Neurosurgery, or brain surgery, is immediate. Neurosurgery
can often remove the entire tumor with low or acceptable risk.
Rapid Resolution
When symptoms (weakness, numbness, diminished
consciousness) are rapidly progressing, an immediate therapy is necessary.
Neurosurgery can remove the source of the neurological deficit relatively
rapidly.
Neurosurgery can successfully treat many different tumors, both benign and
malignant. The malignant tumors treated most often are the "brain metastases"
or tumors that have spread to the brain. When the brain metastases are solitary
or single, neurosurgical resection is particularly attractive.
The malignant gliomas are frequently treated with neurosurgery both
initially and at the time of recurrence. Because the gliomas (fibrillary,
anaplastic and glioblastomas) can infiltrate (spread via "fingers" into
surrounding normal brain) complete resection is often difficult. For the
pilocytic astrocytomas, the neurosurgery can often result in complete
removal.
Many "benign" tumors can be successfully treated with neurosurgery. These
include the acoustic neuromas, meningiomas and pituitary adenomas. For the
acoustic neuromas, neurosurgery offers immediacy of treatment but may have
higher risk to the facial motor and sensory nerves when compared to
radiosurgery. For the meningiomas neurosurgery is often employed for total or
subtotal removal. If the meningioma is "deep" or is in the cavernous sinus,
radiosurgery is often a useful treatment. For the pituitary adenomas,
neurosurgery can rapidly decrease hormonal production. If the resection is
complete, no further treatment may be required.
What are the different types of specialties in brain tumor
Neurosurgery?
The skull base Neurosurgery treats meningiomas of the cavernous
sinus, medial sphenoid wing, parasellar and olfactory groove. The skull base
Neurosurgery also treats acoustic neuromas, chordomas of the clivus, and
pituitary adenomas.
The malignant brain tumor Neurosurgery treats the malignant intrinsic
brain tumors including the glioblastoma multiforme, anaplastic astrocytoma,
anaplastic oligodendrogliomas, brain metastases, pineal tumors including
pinealomas and pineoblastomas. The malignant brain tumor Neurosurgery also
treats lymphomas of the brain, medulloblastomas, germinomas, embryonal cell
carcinomas and teratomas.
