Thyroid and Parathyroid

Clinical examination and the history often suggest the source of the metastatic
disease, and FNAC usually provides definitive diagnosis. Resection of the thyroid,
. usually lobectomy, may alleviate symptoms in symptomatic cases
SURGERY OF THE THYROID
Patients who have had any change in voice or any previous neck surgery should have
a preoperative vocal cord assessment, by direct or indirect laryngoscopy. Patients
should be euthyroid at operation. On the operating table, a sandbag should be placed
between the patient's shoulder blades, the head supported by a ring, and the neck
. extended to provide optimal exposure
Operative Technique
A Kocher transverse collar incision is sited in a skin crease about 1 cm below the
cricoid cartilage and carried through the platysma muscle (Fig. 36-29). The length of
the incision varies, typically around 5 cm, and it should be symmetrical. Longer
incisions are necessary in patients with larger tumors, in patients with a short, fat neck
or whose neck cannot be extended, and in patients with low-lying thyroid glands. The
upper flap is dissected in an avascular subplatysmal plane anterior to the anterior
jugular veins and deep to the platysma muscle, to the level of the thyroid cartilage.
The lower flap is then mobilized in a similar manner, to the suprasternal notch. Skin
towels and a self-retaining retractor are applied. Meticulous hemostasis in
thyroidectomy facilitates the identification of the parathyroid glands and the recurrent
. laryngeal nerves, reducing the possibility of inadvertent damage
The thyroid gland is exposed via a midline incision through the superficial layer of the
deep cervical fascia between the sternohyoid and sternothyroid muscles (Fig. 36-30).
Care should be taken not to disrupt the veins on the thyroid surface. On the side to be
dissected first, the more superficial sternohyoid muscle is separated from the deeper
sternothyroid muscle by blunt dissection. The dissection proceeds laterally until the
ansa cervicalis is noted on the lateral edge of the sternohyoid muscle and the medial
aspect of the internal jugular vein. The deeper sternothyroid muscle is dissected free
from the thyroid gland by blunt or sharp dissection, exposing the middle thyroid vein
or veins laterally. The thyroid lobe is retracted anteromedially by finger traction and
the lateral tissues swept posterolaterally by a pledget. The middle thyroid veins are
divided and ligated. In rare cases the strap muscles must be divided in order to gain
access to a large thyroid tumor. When this maneuver is necessary, the muscles should
be divided high so that innervation from the ansa hypoglossal nerve is preserved.
Occasionally a thyroid cancer invades the strap muscles; in this situation the involved
. muscles should be removed en bloc with the thyroid
The superior thyroid pole is identified by retracting the thyroid inferiorly and
medially. The tissues lateral to the upper pole of the thyroid and medial to the carotid
sheath can be mobilized quickly by blunt dissection, because there are no nerves in
that region. The upper pole of the thyroid is then mobilized caudally and laterally. The
dissection plane should be close to the thyroid to avoid possible injury to the external
branch of the superior laryngeal nerve. An effort should be made to identify and
preserve the branch of the external laryngeal nerve that supplies the cricothyroid
muscle. The branch is visible in about 80 percent of patients on the cricothyroid