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A thyroidectomy is the removal of all or part of your thyroid gland. The thyroid gland produces hormones that regulate the body’s metabolic rate controlling heart, muscle and digestive function, brain development and bone maintenance.
The gland is located in the front of the neck and consists of two lobes and a connecting part called the isthmus. There are three main reasons why it would be necessary to operate on the thyroid gland. These are:
- Gross enlargement with cysts of a normal or hypo-functioning gland (a hypo-functioning gland has decreased or insufficient function) leading to difficulties in swallowing, difficulty breathing or pain if there is bleeding into the cyst. Sometimes the decision to operate can solely be due to a poor cosmetic appearance because of the enlarged gland.
- A hyperfunctioning gland (abnormally increased function) that cannot be controlled by medication or radioactive iodine.
- Suspicion of cancer or established cancer of the thyroid gland.
There are some other, very rare, indications such as a thyroid gland located in the tongue or the chest and more.
For the more common indications, a removal of one lobe of the thyroid gland with the isthmus or removal of the entire thyroid gland are usually what is recommended. In some cancer operations, lymph nodes in the neck may also be removed. In a thyroidectomy, an incision is placed in the front of the neck and the neck muscles are either retracted or divided. The thyroid lobe or the entire thyroid are then removed. After the operation, a drain is generally placed in the neck that will be removed the next day, in most cases.
It is important to note that thyroid surgery can have complications. Next to the general complications of postoperative bleeding and infection (which are rare), there are others that are rarely life-threatening but can be especially bothersome.
This is due to the special anatomy of the thyroid gland. It is located in the neck in close proximity to important nerves and blood vessels as well as the parathyroids, which are important in calcium metabolism.
Two nerves on each side can be injured in thyroid operations – the recurrent laryngeal nerve and the superior laryngeal nerve.
The recurrent laryngeal nerve runs in very close proximity to the back of the thyroid gland and supplies the vocal chords. It is a small nerve, about one millimetre in diameter, has a variable anatomy and needs to be handled delicately as it is easily injured. Injury to the nerve manifests itself by hoarseness due to the vocal cord on the injured side becoming paralysed. This can be improved by speech therapy or by specialised treatments such as silicone injections into the affected cord.
If both recurrent laryngeal nerves are injured, the paralysed vocal chords are then positioned very close together and the airway is obstructed. An emergency tracheotomy (cutting a hole into the trachea under the larynx so that the patient can breathe) then needs to be performed.
The superior laryngeal nerve lies in proximity to the upper part of the thyroid lobe on each side. It is seen only in about 25% of the cases in the operative field (otherwise not usually visible in the operative field). Similar to the recurrent laryngeal nerve, it is very small and can easily be injured but an injury is less likely. An injury can also be bothersome as the tension of the vocal cord on the affected side is lost. The voice becomes tired easily, a problem for singers or in professions that depend on a lot of talking.
A further complication of a total thyroidectomy or repeat surgery on the thyroid gland is injury to the parathyroid glands. These are four small glands that are located in close proximity to the posterior thyroid capsule (the thyroid gland is covered by a thin fibrous capsule, which has an inner and an outer layer) as well as the recurrent laryngeal nerve. They share the blood supply with the thyroid gland. Due to their small size (5 mm diameter, 50 mg weight) and their camouflage (only a trained eye can distinguish between the thyroid tissue and the lymph nodes in the area) they are easily injured during thyroidectomy either directly or by injury to their blood supply.
If parathyroid glands are injured, calcium levels can drop to critical levels and the patients develop severe cramps that can only be relieved by giving intravenous calcium.
Surgeons which have a special interest in thyroid and parathyroid health and consequently do higher volumes of such surgery have a much lower rate complications.
Endoscopic (keyhole) surgical approaches have been described for thyroid surgery, but currently these are not favoured as only a few patients qualify and access from the oral cavity or the armpit is cumbersome with much more extensive dissection and consequent scarring on the access routes. Operation times are also much longer and complications more frequent. Therefore, these techniques are currently experimental.
In summary, surgery for thyroid disease is an essential part of thyroid health but the results, as proven in many aspects of health care, are much better in the hands of specialised, high-volume centres.