Thyroid and Parathyroid

and the thyrothymic tongue of fat (thyrothymic ligament) that extends inferiorly
toward the mediastinum. Many inferior parathyroid glands are subcapsular, i.e.,
attached to the inferior aspect of the thyroid lobe and covered by a thin layer of
fibrous tissue. This does not represent an intrathyroid parathyroid gland, as is often
erroneously assumed. To be truly intrathyroid, the parathyroid gland should be
. circumferentially surrounded by thyroid parenchyma
If the superior parathyroid gland is not visualized, the tracheoesophageal groove
should be explored digitally. Enlarging superior parathyroid adenomas often descend
into this groove and can be palpated accurately by inserting a finger into the avascular
space immediately superior to the inferior thyroid artery (Fig. 36-52). Such glands are
often located inferior to the inferior parathyroid glands. The parathyroid glands can be
found from as high as the angle of the mandible or the base of the skull (undescended
parathymus) to as low as an intrathymic location in the anterior mediastinum or in the
. aortopulmonary window in the posterior mediastinum
In the hands of an experienced surgeon, a negative exploration usually is the result of
an unusual variation in embryologic descent. The following rule is useful in this
situation: If the superior parathyroid gland is not found in its conventional position,
the surgeon should search inferior to the inferior parathyroid gland for the superior
parathyroid gland (tracheoesophageal groove); conversely, if the inferior parathyroid
gland is not found inferior to the superior parathyroid gland, the surgeon should
search superior to the superior parathyroid gland for the inferior parathyroid gland
(undescended parathymus). If these simple maneuvers are unsuccessful, the surgeon
should become suspicious that the offending parathyroid gland might be in one of the
: following locations
In the thymus. A fairly complete transcervical thymectomy should be performed
. to search for the missing inferior gland
Within the thyroid. Truly intrathyroid glands are exceedingly rare. Most so- ( 2)
called intrathyroid parathyroid glands are inferior parathyroid glands located beneath
. the thin veil of the thyroid capsule and can be easily teased off the thyroid
In the carotid sheath. This is extraordinarily rare, but opening the carotid sheath
. should be considered when all other possibilities have been ruled out
Lateral to the carotid sheath. This location is even more unusual than in the
. carotid sheath, but the parathyroid gland can hide laterally
Routine bilateral exploration is recommended in all patients. If a single adenoma is
identified, excision of this adenoma, without biopsy of normal glands, is suggested. If
hyperplasia is documented, all but approximately 50 mg of clearly viable parathyroid
tissue is excised and routine transcervical thymectomy is performed. With the
approach outlined, surgical success should approach 99 percent. Permanent laryngeal
. nerve palsy or hypoparathyroidism occurs in less than 1 percent of patients
Persistent and Recurrent Hyperparathyroidism
Almost twenty years ago, Wexler stated, “Persistent hypercalcemia in suspected
hyperparathyroidism is due to an improperly performed primary operation.” This
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