The thyroid
gland is located over the trachea
(windpipe) just below the larynx
(voice box), and it has two lobes
that extend along each side of the
trachea. The central portion of the
gland is called the isthmus. The
function of the thyroid gland is
discussed on another
web page.
Patients who have total
thyroidectomy will need to be on
hormone replacement therapy, meaning
taking a tablet daily, for the rest
of their lives. Patients who have
partial removal of the gland usually
do not require daily thyroid hormone
replacement, but this can vary
depending on the underlying thyroid
disease.
The
parathyroid glands are located
alongside the lobes of the thyroid.
There are usually two parathyroid
glands on each side of the neck.
The parathyroid glands regulate
calcium levels in the blood.
Without the any of the parathyroid
glands, calcium levels can drop to
dangerously low levels. Surgery
around the thyroid gland requires
identification and preservation of
as many of these glands as
possible. Sometimes, this very
disection around the parathyroid
glands can disturb their blood
supply and temporarily affect their
functioning. Occasionally, tumors
of the thyroid invade and destroy
these glands, making their
preservation impossible. In such
circumstance, if one gland can be
positively identified, then it can
be implanted (autotransplant)
and it will begin functioning
several weeks after surgery. In the
meanwhile, calcium replacement and
Vitamin D are given to maintain
normal parathyroid hormone levels.
The
nerves that control the vocal folds
are located near the thyroid gland.
On each side of the neck, there is a
superior laryngeal nerve and an
inferior (more commonly called
recurrent) laryngeal nerve.
Each nerve controls its own set of
muscles and provides sensation to
its own part of the larynx. The
superior laryngeal nerve has two
branches: an external branch that
controls the cricothyroid muscle,
and an internal branch that gives
sensation to the larynx above the
vocal folds. The cricothyroid
muscles repositions the thyroid
cartilage over the cricoid
cartilage. This action tenses the
true vocal folds, allowing the voice
to reach higher notes. Damage to
this nerve eliminates the ability to
reach the high notes.
The
recurrent laryngeal nerve controls
the other muscles of the larynx and
provides sensation to the rest of
the larynx. Its most important
functions are to open the true vocal
folds allowing unrestrained
respirations and to close the vocal
folds producing a normal voice,
cough, and swallow. Damage to one
recurrent laryngeal nerve produces a
breathy, low-volume voice and poor
cough reflex. It might also produce
difficulty with swallowing so that
one's food or drink might go down
the trachea (also called
aspiration). Damage to both
recurrent laryngeal nerves prevents
adequate opening of the true vocal
folds, and results in shortness of
breath. Voice quality might,
however, be relatively normal with
bilateral recurrent laryngeal nerve
paralysis. Sometimes the
respiratory difficulty from
bilateral recurrent laryngeal nerve
injury might be so severe as to
require tracheostomy.
-
Vocal fold weakness or
paralysis, due to damage to one
or more of the nerves that
control vocal fold movement
-
Low calcium levels, due to
damage or loss of the
parathyroid glands
-
Hematoma formation
-
Infection
-
Hypothyroidism, need for daily
thyroid hormone replacement
Thyroidectomy is performed under a
general anesthetic. The patient is
positioned in such a way that the
neck is extended slightly.
Prophylactic antibiotics are given
just prior to starting the
procedure.
After
the patient is draped in sterile
towels and drapes, an incision is
planned, usually about two
fingerbreaths above the bony notch
at the base of the neck. This
incision is carried down through the
soft tissues of the neck until the
strap muscles that cover the thyroid
are found. These strap muscles are
separated and spread apart to expose
the thyroid gland. The inferior
part of the diseased gland is then
mobilized. The recurrent laryngeal
nerve and parathyroid glands are
identified and preserved. The
superior part of the gland is
followed closely to avoid injury to
the superior laryngeal nerve. The
diseased thyroid lobe is then
removed, usually by dividing the
isthmus (isthmusectomy), and leaving
the normal lobe alone.
The
surgical specimen is usually sent
for a rapid or frozen section
pathologic diagnosis. If the frozen
section reveals a benign disease
process, then a surgical drain is
placed to prevent accumulation of
blood or fluid in the surgical bed.
The wound is then closed in layers
with sutures.
If
the frozen section pathologic
diagnosis discloses a malignancy,
then the remaining gland is usually
removed (see total thyroidectomy).
Sometimes the frozen section cannot
definitely find evidence of
malignancy. In this circumstance,
one must wait for the final
pathologic diagnosis (usually 3 -
5 business days). If a
malignancy is found on the final
pathologic diagnosis, then a
completion thyroidectomy is
scheduled for the near future (usually
within a week or two of the original
surgery date).
This
procedure is begun in the same
fashion as described in Total
Thyroid Lobectomy and Isthmusectomy.
However, the isthmus is usually not
divided, and both lobes of the
thyroid are mobilized. Each
recurrent laryngeal nerve is
identified and preserved. The
parathyroid glands are identified
and preserved. The entire gland is
removed.
In
cases of aggressive malignancy, the
recurrent laryngeal nerve, superior
laryngeal nerve, or parathyroid
gland cannot be separated from the
tumor. In these cases, the nerve or
parathyroid gland has to be
sacrificed in order to remove the
tumor completely. If at least one
of the parathyroid glands can be
identified, then it can be implanted
into one of the strap muscles (autotransplantation).
The
surgical specimen is usually sent
for a rapid or frozen section
pathologic diagnosis. Once the gland
is removed, a surgical drain is
placed to prevent accumulation of
blood or fluid in the surgical bed.
The wound is then closed in layers
with sutures.
This
procedure is begun in the same
fashion as described in Total
Thyroid Lobectomy and Isthmusectomy.
The remaining lobe of the thyroid is
mobilized. The recurrent laryngeal
nerve is identified and preserved.
The parathyroid glands are
identified and preserved. The
remaining gland is removed.
In
cases of aggressive malignancy, the
recurrent laryngeal nerve, superior
laryngeal nerve, or parathyroid
gland cannot be separated from the
tumor. In these cases, the nerve or
parathyroid gland has to be
sacrificed in order to remove the
tumor completely. If at least one
of the parathyroid glands can be
identified, then it can be implanted
into one of the strap muscles (autotransplantation).
A
frozen section is not necessarily
performed, since the diagnosis has
already been determined. The
surgical specimen will be examined
and a pathology report will be
issued within 3 to 5 business
days.
Once
the gland is removed, a surgical
drain is placed to prevent
accumulation of blood or fluid in
the surgical bed. The wound is then
closed in layers with sutures.
The
patient is kept in hospital for at
least one day. Prophylactic
antibiotics are continued for the
first day. The patient is observed
for the potential problems of
hematoma formation and hypoclacemia.
Accumulation of blood (hematoma)
in the operative bed can occur in
the first 24 hours. When this
occurs, the accumulated fluid can
displace the trachea and make
breathing difficult. This hematoma
needs to be drained and the bleeding
site controlled.
During the post-operative
hospitalization, calcium levels are
checked. In cases of total
thyroidectomy, when all of the
parathyroid glands have been
disturbed, checking calcium levels
is very important. Calcium levels
can drop to levels that produce
symptoms such as tingling around the
mouth or fingertips. Replacement of
calcium and vitamin D are given to
restore the calcium level to
normal. Patients with low calcium
are observed until the calcium level
stabilizes. If just one of the
parathyroid glands has been
preserved (or sometimes
autotransplanted), then calcium
levels will stabilize in time.
Patients that have had total
thyroidectomy for benign disease are
started on thyroid hormone
replacement. Patients that have had
total thyroidectomy for malignant
disease are not started on thyroid
hormone replacement, until a thyroid
survey has been performed (usually
within the first 6 weeks after
surgery).
Most
patients have some discomfort with
swallowing for the first few days,
and this is normal. When the
recurrent laryngeal nerve is
sacrificed, patients will have more
difficulty with swallowing and a
weaker than normal voice. Many
patients notice improvement in
swallowing and voice with speech
therapy. Sometimes a surgical
procedure to move the vocal fold
toward the opposite fold can be
performed to improve the voice and
eliminate aspiration.
The
duration of hospitalization is
usually dictated by either the
amount and duration of drainage
through the surgical drain or the
occurrence of one of the
complications listed above. If the
postoperative course is
uncomplicated, then this drain is
removed, and patients are generally
able to go home.
Patients are seen about one week
after surgery. Stitches, if
present, are removed. An evaluation
of vocal fold movement is usually
conducted.
For
patients with benign disease,
thyroid replacement hormone is
continued and TSH levels are checked
periodically until an appropriate
level of hormone replacement has
been reached. These patients are
generally followed in consultation
with endocrinologists.
For
patients with malignant disease,
thyroid hormone replacement is
delayed until a thyroid survey can
be obtained. This nuclear thyroid
scan looks for any sign of residual
or metastatic thyroid disease.
Patients are then treated with
ablative doses of radioactive
iodine. These patients are
generally followed in consultation
with endocrinologists and/or
oncologists. Periodic examinations
and blood tests are performed to
find any recurrence of the cancer.
For
postoperative thyroidectomy
instructions, click
here.