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HYPOPHYSECTOMY PITUITARY GLAND SURGERY
Category: Neurosurgery
Abstract : Hypophysectomy, or hypophysis, is the surgical removal of the pituitary
gland. Purpose : The pituitary gland is a small, oval-shaped endocrine gland
about the size of a pea located in the center of the brain above the back of the
nose. Its major role is to produce hormones that regulate growth and metabolism
in the body. Removing this important gland is a drastic step that is usually
Hypophysectomy, or hypophysis, is the surgical removal of the pituitary
gland.
Purpose : The pituitary gland is a small, oval-shaped endocrine gland
about the size of a pea located in the center of the brain above the back of the
nose. Its major role is to produce hormones that regulate growth and metabolism
in the body.
Removing this important gland is a drastic step that is usually
taken in the case of cancers or tumors that resist other forms of treatment,
especially craniopharyngioma tumors. Hypophysectomy may also be performed to
treat Cushings syndrome, a hormonal disorder caused by prolonged exposure of
the bodys tissues to high levels of the hormone cortisol, in most cases
associated with benign tumors called pituitary adenomas. The goal of the surgery
is to remove the tumor and try to partially preserve the
gland.
Demographics : Craniopharyngiomas account for less than 5% of all
brain tumors. Half of all craniopharyngiomas occur in children, with symptoms
most often appearing between the ages of five and ten. Cushings syndrome is
relatively rare in the United States, most commonly affecting adults aged 20 - 50.
An estimated 10 - 15 of every million people are affected each year. However, the
Pituitary Network Association reports that one out of every five people
worldwide has a pituitary tumor. The earliest study was performed in 1936, by
Dr. R. T. Costello of the Mayo Foundation who found pituitary tumors in 22.4% of
his studied population with statistics not having changed significantly since
that time.
Description : There are several surgical approaches to the
pituitary. The surgeon chooses the best one for the specificprocedure. The
pituitary lies directly behind the nose, and access through the nose or the
sinuses is often the best approach. A craniotomy (opening the skull) and lifting
the frontal lobe of the brain will expose the delicate neck of the pituitary
gland. This approach works best if tumors have extended above the pituitary
fossa (the cavity in which the gland lies).
Surgical methods using new
technology have made other approaches possible. Stereotaxis is a
three-dimensional aiming technique using x rays or scans for guidance.
Instruments can be placed in the brain with pinpoint accuracy through tiny holes
in the skull. These instruments can then manipulate brain tissue, either to
destroy it or remove it. Stereotaxis is also used to direct radiation with
similar precision using a gamma knife. Access to some brain lesions can be
gained through the blood vessels using tiny tubes and wires guided by x
rays.
Diagnosis/Preparation : A patient best prepares for a
hypophysectomy by keeping as healthy and relaxed as possible. Informed surgical
consent is always required. The patient is first seen for evaluation of
pituitary functions by the treatment team. An MRI scan of the pituitary gland is
performed and the patient is seen by a neurosurgeon in an outpatient clinic or
at the hospital to assess whether hypophysectomy is suitable.
The patient
checks into the hospital the day before surgery and undergoes blood tests, chest
x rays, or an electrocardiogram to assess anesthesia fitness. Four to five
sticks are attached on buttons on the forehead and marked for a special MRI
scan. These buttons and scan help the neurosurgeon to accurately remove the
pituitary tumor using sophisticated visualization computers. The patient is
visited by the anesthesiologist (the physician who puts the patient to sleep for
the operation) and he is asked to fast (nothing to eat or drink) from midnight
before the day of surgery. If the hypophysectomy is performed through the nose,
the patient is advised to practice breathing through the mouth as the nose will
be packed after the surgery.
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