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Introduction
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You CAN
understand your operation! No matter how complicated or specialized the
procedure, if you can read and have a high school level education, you can
understand how and why your operation is done. Neurosurgery is complicated
not because of the instruments, techniques, or procedures used, but because
of the complexity of the nervous system anatomy, physiology, and pathology.
Once you understand the reasons for your operation and the strategies for
treating your problem you will realize that there is nothing magical about
neurosurgery -- and that you don't have to be a "brain surgeon" to
understand brain surgery! |
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Surgical indications |
Why the
operation is being done.
The reason for your surgery is a lesion (problem) that the
surgeon wants to manipulate to cure or control your symptoms.
Common intracranial neurosurgical pathology is related
to problems of brain blood vessels (cerebrovascular: aneurysms,
arteriovenous malformations), tumors (neurooncology: gliomas, metastatic
cancer, meningiomas), injuries (neurotrauma: hematomas, fractures), or of
cerebrospinal fluid (hydrocephalus).
Spinal pathology most frequently operated is
degenerative (decompression, stabilization), post-traumatic (evacuation of
hematoma, reconstruction), or neoplastic (resection, debulking) in nature.
Surgical peripheral nerve pathology includes tumors as
well as injuries due to intrinsic or extrinsic trauma.
When surgeons speak of surgical indications they
frequently use the qualifiers "absolute" and "relative". Surgeries that are
"absolutely" indicated are necessary to protect the patient from almost
certain adverse consequences. "Relatively" indicated operations are to
resolve problems that without intervention will probably worsen and cause
the patient future trouble.
Examples: 1.
transsphenoidal craniotomy is indicated for removal of a pituitary
tumor that is causing compression of the optic chiasm 2. embolization of a
cerebral arteriovenous malformation is indicated to reduce the number
of feeding vessels so that open resection (indicated to eliminate
further potentially damaging or fatal hemorrhage) can be performed more
safely. |
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Surgical objectives |
What the surgeon intends to do.
Based on the pathology but considering also the
anticipated difficulty in exposing the target pathology, the manipulations
required at the target, as well as the possible consequences intraoperative
and post-operative complications, the neurosurgeon formulates surgical
objectives: what he believes he can safely accomplish with the operation he
proposes.
Variability in nature and extent of pathology, surgeon
skill and experience, patient physiology and anatomy make it impossible to
establish absolute objectives for any operation. Each patient's problem
must be evaluated and treated individually as a particular, unique case.
Examples: 1.
the objective of craniotomy for resection of a parafalcine meningioma
over the convexity of the brain is to remove all but microscopic traces of
the tumor without damage to the underlying brain or to the sagittal sinus to
which this particular lesion is attached.
2. the objective of
transsphenoidal craniotomy is removal of a pituitary tumor including the
portion of it extending into the cavernous sinus without injuring the
carotid artery lying immediately next to the lesion. |
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Lesion considerations |
How attributes of the pathology affect the surgical
planning and execution.
The almost infinite possible
combinations of anatomic location, size, aggressiveness, vascularity, and
consistency make pathologic lesions virtually as unique from case to case as
are the patients in whom they occur.
In recommending and planning a procedure the
neurosurgeon considers how he will do what needs to be done (cutting,
coagulating, moving, removing) to an object of anticipated consitency,
likeliness to bleed, and possible intimate contact (pressing against or
invasion) or nearby structures.
Consideration of the lesion involves not only the lesion
itself but also the potential danger to nearby structures by manipulation of
the lesion. |
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Exposure |
Portion of the nervous system that must be exposed for
the surgeon to visualize and manipulate the target pathology adequate to
accomplish the surgical objectives.
The exposure is what the neurosurgeon will see and the
space in which he will be able to work once the skin is opened and
intervening tissues have been divided and separated allowing visual and
physical access to the target pathology (lesion).
Neurosurgeons have come up with a set of exposures for
attacking lesions as virtually any site in the central or peripheral nervous
system. Sometimes these exposures are expanded or modified to deal with
surgically problematic variations in lesion nature or location, but most are
variations on the limited standard neurosurgical exposure set.
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Approach |
Structures that must be cut,
separated, moved, or removed to reach the target and accomplish the surgical
objectives.
Division, dissection, drilling, sawing are the surgical
techniques that will be required to create a passageway from the skin
surface to the surgical target large enough that the surgeon can see well
at the depth where the target lesion is, and not so deep that he cannot work
comfortably and safely on the target. |
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Landmarks |
Structures visible on the surface of the skin or
palpable through it that orient the surgeon with respect to the proposed
approach and exposure.
The location of the exposure,
approach, and skin incision are translated onto the patient in reference to
landmarks on his or her head, back, or extremities. Creases in the
skin and prominences of bone that are present in all patients constant with
respect to underlying brain, spinal cord, or peripheral nerves are useful
neurosurgical landmarks.
Gallery of landmarks |
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Hazards |
Structures in proximity to the approach, exposure,
and target manipulation injury to which could result in neurologic deficit,
physiologic compromise, or jeopardy to completion of the operation.
Reaching and then exposing a surgical target adequate
for visualization and manipulation in the central and peripheral nervous
system frequently requires dissection, retraction, and manipulation around
occult (hidden behind other structures), delicate, or sensitive structures.
Delicate structures are those with thin walls or necks
easily broken by even the gentlest touch with a dissecting instrument.
Sensitive structures are those nervous structures (like
the third canial nerve or the pituitary stalk) that, while remaining intact,
stop functioning normally following surgical retraction or manipulation
trauma.
Hazards should either be sought or avoided. Sometimes
they are sought and when identified marked prominently with a tie to remind
the surgeon of their presence and location.
Finding and staying away from hazardous structures
requires knowledge of anatomic dissection.
Each approach and exposure is associated with particular
hazards the presence of which should figure prominently into formulation of
surgical objectives and planning, and in patient informed consent! |
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Instruments |
Devices and tools used to position the patient, approach
and expose the target pathology, and accomplish the surgical objectives. |
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Anesthesia |
A combination of drugs administered by a variety of
techniques and routes by trained professionals that provide sedation,
amnesia, analgesia, and immobility adequate for accomplishment of the
surgical objectives with minimal discomfort, and without injury, to the
patient.
Some operations require that the patient remain
immobile, anesthetic, and amnesic for many hours at a time. From a variety
of anesthetic options for any given procedure, the surgeon and
anesthesiologist selects those that in patients demographically (diagnosis,
age, neurologic condition) similar to the one being operated on, most
reliably produce safe, effective, uncomplicated anesthesia in as
non-invasively as possible. |
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Monitoring |
Tracking of physiologic parameters that provides
feedback about surgical maneuvers proceeding without injury and warnings
about those that are not.
Monitors with alarms can be
attached to structures that are hazards to help the surgeon avoid injury to
these. |
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Position |
Arrangement in space of the patient's body and
appendages both safe and adequate to accomplishment of the surgical
objectives.
Positioning is more than locating the head or back in
surgical space. Attention must also be paid to the location of the torso
and abdomen as well as the extremities. The surgeon has a variety of
surgical positioning options for any desired exposure. |
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Prep and drape |
Cleansing of the patient's skin and placement of
surgical drapes to create a sterile surface surgical field.
Most modern neurosurgical procedures (exceptions:
transsphenoidal craniotomy, tracheostomy) are done under sterile
conditions. |
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Incision |
Division of the skin with a scalpel blade.
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Dissection |
Process of cutting and separating of the body's tissue
to reach a surgical target location.
Dissection can be blunt (done with a finger) or sharp
(requires knife, scissors). Whenever possible the surgeon attempts to
dissect along preexisting planes (spaces of natural tissue cleavage) that
contain none of the nerves or vessels to be injured and potentially
contribute to a bad outcome.. |
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Target manipulation |
What the surgeon needs to do to the target pathology
to accomplish the surgical objectives.
Neurosurgery is done for a number of different
pathophysiologic indications. At the target the neurosurgeon performs
complex manipulations (such as placing a clip across the neck of an
aneurysm).
Once the neurosurgeon gets to the target pathology what
does he or she do. |
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Problems |
Intraoperative misadventures |
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Hemostasis |
Stopping bleeding.
The most difficult part of most neurosurgical procedures
is control of hemorrhage. Blood obstructs the surgeon's view of the
surgical field and must be irrigated and suctioned away if dissection and
manipulation in or near the spinal cord, brain, or nerve is to continue once
even a small volume of it accumulates.
A variety of materials and techniques are used for hemostasis
depending on the source (artery or vein), location, or rate of hemorrhage. |
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Closure |
Techniques of re-approximation of deeper to more
superficial layers and ultimately of the edges of the skin incision prior to
placement of a dressing.
Closure of a surgical wound requires closure of every
layer of tissue cut or divided to reach the surgical target. Once
hemostasis is obtained the surgeon begins "to close".
Sutures are used to hold divided tissues together. They are
particularly important for tissues that contain other tissues under pressure
-- if the wound opens along the suture line, deep contents can herniate
through.
Skin staples are popular with surgeons. Recently developed
tissue adhesive glue may replace the always unsatisfactory choice between
skin staples (patients hate the pain, neurosurgeons the time, of taking them
out) and sutures (patients hate the pain, neurosurgeons the time, of taking
them out). |
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Drains |
Devices with an inflow channel placed in areas where hemostasis was
problematic at the time of closure where continued bleeding may occur, with
outflow into a collection chamber in which the volume collected can be
measured. |
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Dressings |
Sterile
coverings placed over surgical wounds to absorb post operative oozing of
blood and protect against incision contamination. |
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Duration |
Time required to perform the procedure.
Operating room preliminaries: transport and
transfer. Induction. Lines.
Patient setup: Positioning. Prep and drape.
Surgery: opening. Dissection. Target manipulation.
Hemostasis. Closure. |
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Post Op |
What happens immediately (first few hours to days) after
surgery.
At the termination of surgery the neurosurgeon writes
"post-op orders" which are instructions to nurses, pharmacists, therapists,
other physicians, etc. for care of the patient on leaving the operating
room.
Once anesthesia is confident that the patient is stable
he authorizes transport to the immediate post op area. The majority of
patients go to the Recovery Room, but some critical patients may be taken
directly back to the Intensive Care Unit where they are "recovered" from
surgery rather than stopping for an hour in Recovery on the way to ICU.
Following a craniotomy for almost any indication (removal of
brain tumor, evacuation of traumatic blood clot, ...) the patient is
initially nursed with the head of the bed elevated to 30 degrees. |
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Recovery |
Time required to return to pre-operative state
(particularly with respect to pain, strength, function, and-well being).
Many patients are concerned about their post operative
recovery time. The most common reasons for concern are job and school.
Patients in good overall physical health will recovery
fastest. Most of these patients will be up and about in their rooms and on
the halls a few hours after an uncomplicated microdiscectomy. Healthy
patients are up and about, eating sitting in a chair one day after an
uncomplicated brain tumor resection or aneurysm clipping. Most patients
leave the hospital the morning after ventriculoperitoneal shunt insertion,
lumbar microdiscectomy, stereotactic brain biopsy, ...) |
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Rehabilitation |
Course of treatments and therapies that promotes patient
functional adaptation, compensation, and recovery from injury.
Only a small percentage of all neurosurgical patients require
post-operative rehabilitation (in-patient or out-patient physical,
occupational, or speech therapy.
Patients who go to surgery with a problem that might benefit
from evaluation and work with a speech, occupational, or physical therapy
are the ones who need it post-operatively.
Some patients who go to surgery completely normal suffer
injuries that lead to a neurologic deficit severe enough to require post-op
rehabilitation. |
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Follow
up |
After surgery the patient and his family are responsible for
returning to the neurosurgeon's office for at least one post-operative visit
at which the surgeon can make sure that the wound is likely to heal without
infection or further bleeding and that the patient is no worse
neurologically or in terms of the Chief Complaint. After that, there is no
guarantee: there may still be delayed complications -- infection, scar
tissue formation, tumor recurrence -- complications that could cause
permanent neurologic injury or death. It is essential, therefore that
patients follow up after surgery in compliance with the recommendations of
their neurosurgeon. |
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Reoperation |
Patients return for repeat surgery for a number of reasons. |
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Risks & complications |
All surgical procedures are associated with risks and
complications that vary depending on the location of the procedure (the
approach and dissection required), the pathology (what has to be done to
accomplish the surgical objective, and patient factors (such as age, general
medical condition, etc.)
Risks and Complications of Neurosurgical Procedures |
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Prognosis |
Prediction of outcome based on pathology, patient
physiology, as well as intraoperative course and findings.
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