Thyroid and Parathyroid

the nerve also is sensory to the larynx and because the vocal cords do not
. approximate, patients also describe choking and coughing when drinking fluids
When damage is temporary, vocal cord function usually returns within 6 months, but
it may take 1 year. When function has not returned by 6 to 12 months, injection lateral
to the cord with Teflon mobilizes the cord to the midline and improves the voice.
Occasionally the contralateral cord compensates and vocal cord paralysis may be
unnoticed, so all patients should have direct or indirect laryngoscopy to evaluate vocal
cord function before reoperation. Speech therapy also helps some patients with vocal
. cord dysfunction and should be done before Teflon injection
Identification of the recurrent laryngeal nerves during surgery has been shown to
decrease the incidence of permanent damage, although transient paralysis is more
common. When nerves are not identified, transient paralysis is reduced, but the
incidence of permanent damage is three or four times higher. Disease-specific risk
factors for permanent nerve damage, in order of frequency, include recurrent thyroid
cancer or recurrent goiter, thyroid cancer, large substernal goiters, chronic
. lymphocytic thyroiditis, Graves' disease, and euthyroid nodular goiter
A rare cause of injury to a laryngeal nerve is that it is a nonrecurrent laryngeal nerve.
This anomaly occurs in about 0.5 percent of patients and is almost always
encountered on the right side. Awareness of this possibility reduces the risk of nerve
. injury when the recurrent nerve cannot be identified at the usual site
Meticulous hemostasis, precise dissection between the thyroid capsule and sheath, and
care dissecting Berry's ligament, where injuries are most likely to occur, all help to
reduce the possibility of damage. The right recurrent laryngeal nerve takes a more
oblique course in the neck as it loops around the subclavian artery, whereas the left
recurrent laryngeal nerve loops around the ligamentum arteriosus and assumes a more
midline position in the tracheoesophageal groove. Either nerve may branch before it
enters the larynx posterior to the cricothyroid muscle at the level of the cricoid
. cartilage
Injury of the External Branch of the Superior Laryngeal Nerve
Injury to the external laryngeal nerve results in difficulty shouting or singing high
notes (the nerve is also called the “high note nerve”). The risk of injuring the nerve
can be greatly reduced by retracting the strap muscles laterally to provide adequate
visualization of the superior thyroid pole. A plane is opened by blunt dissection
between the thyroid pole and the cricothyroid muscle bed. In about 80 percent of
patients the nerve can be seen on the cricothyroid muscle. The superior thyroid
vessels are individually ligated and divided low on the thyroid gland, rather than taken
all together in one large bloc to avoid injury to the external laryngeal nerve. If these
.( steps are followed, injury to the nerve is uncommon (2 percent
Hypoparathyroidism
The chances of permanent hypoparathyroidism after thyroidectomy vary with the size
and degree of invasion of the tumor, the type of pathology, the extent of the
procedure, and the experience of the surgeon. Total thyroidectomy and central neck
compartment clearance in medullary thyroid carcinoma has a higher incidence of
subsequent hypoparathyroidism than does subtotal thyroidectomy for multinodular