Surgery of the thyroid and parathyroid glands
The thyroid gland is located in the neck, in front of the trachea and below the larynx. It usually weighs 15-20 grams.
It consists of two lobes (left and right), a central part that joins them (thyroid isthmus) and in half the population we also have a pyramidal lobe in the central part of the gland. The thyroid gland produces hormones (T3 and T4) that regulate the body’s metabolism.
When these hormones are produced in amounts above normal, it’s called hyperthyroidism. As a result, patients experience weight loss despite eating a lot, insomnia, high blood pressure and feel constantly hot.
Lower than normal hormone production is called hypothyroidism. Symptoms include drowsiness, lethargy, weight gain and feeling constantly cold. Most thyroid disorders can be treated with appropriate medication and monitoring by an endocrinologist.
The surgical treatment of thyroid disorders consists of either completely removing the gland (total thyroidectomy) or just a part of it (subtotal thyroidectomy or lobectomy) depending on the pathological indications that arise.
Goiter is the swelling of the thyroid, which is easily perceived by the patient as a swelling in the throat. Goiter may coexist with hyper- or hypothyroidism. It used to be observed in geographical areas of the country far from the sea in populations that lacked iodine. As a disorder, it often causes pressure in the throat and this in itself can be an indication for thyroidectomy. Usually, goiters also contain nodular formations called thyroid nodules.
A nodule is a formation of the thyroid which has a different architecture from the rest of the gland. They can be individual or multiple and are caused by hyperplasia of the thyroid gland. When they are diagnosed, it must be established whether they are active or inactive (that is, if they produce thyroid hormones or not), with scintigraphy and if they ‘hide’ any malignancy (this is established by percutaneous puncture and biopsy).
When malignancy is found or when the nodules are multiple and therefore difficult to control, surgery is recommended.
Relatively rare (1% of all cancers), thyroid cancer is the most common endocrine gland malignancy. There are four types of thyroid cancer:
• papillary, which is the most common,
• medullary and
• anaplastic, which has the worst prognosis
Due to the proximity of the thyroid to major vessels, nerves, the esophagus and trachea, surgical procedures in the area require extremely delicate maneuvers by specialized surgeons.
A small horizontal incision of 4-5 cm is made (depending on the size of the preparation) at the base of the cervix. The thyroid (all or part of it) is removed without cutting throat muscles. During surgery, it is extremely important to identify and preserve the recurrent laryngeal nerves and the parathyroid glands, which must remain intact. These nerves lie between the trachea and the esophagus and are almost attached to the back of the thyroid. They innervate the vocal cords and any injury to them can cause anything from hoarseness to difficulty breathing/suffocation, for which a tracheostomy is needed.
For this reason, magnifiers/glasses and a neurostimulator is used. The neurostimulator is a tool in the hands of the experienced surgeon to help identify the laryngeal recurrent, especially in cases where the location of the nerve is not typical. The wound is closed with a plastic suture. The patient is discharged the day after surgery. Once the results of the biopsy are known, the thyroxine supplement that the patient should receive is determined by their endocrinologist.
Lately there has been talk of robotic/endoscopic removal of the thyroid through an axillary incision. It has been widely discussed in many surgical conferences. Beyond any cosmetic advantages, however, it must be proven that this technique is just as safe as the conventional thyroidectomy method.
The parathyroid glands are located at the back of the thyroid. Usually, there are four of them, but in a part of the population (about 20%) there may be a fifth. They produce parathyroid hormone, which is responsible for the metabolism of calcium in the body.
Parathyroid glands are surgically removed in cases of adenoma, hyperplasia or carcinoma. The first two disorders may coincide with overproduction of parathyroid hormone and hyperparathyroidism. Symptoms of this include nausea, a tendency to vomit, muscle weakness, bone pains, automatic fractures, renal colic, nephrolithiasis, or even neurotic and psychotic manifestations.
The surgical indications in asymptomatic patients for parathyroidectomy according to the NIH are as follows:
• serum calcium >12mg/dl
• urine calcium >400mg/24 hours
• cystic fibrous osteitis
• hypercalcemia episode
• 30% reduction in creatinine clearance
The diagnosis is made through blood tests and checking calcium levels in the blood and urine. Also, ultrasound or cervical x-ray and scintigraphy can be helpful.
The surgical approach is similar to thyroidectomy.