Thyroidectomy (Surgery to remove Thyroid Gland)

Thyroidectomy is the medical term for the surgical procedure to remove the thyroid gland. The indications for thyroidectomy are:
- thyroid cancer
- thyrotoxicosis (symptoms of excess of thyroid hormones; refer to earlier topic)
- huge goitre with compressive symptoms (eg. difficulty breathing, difficulty in swallowing)
- cosmesis & patient's request (unsightly neck swelling)

The surgery is performed under general anaesthesia and hospital admission is necessary. Prior to surgery, the patient's thyroid function should be assessed. Patients who are hyperthyroid should be treated with anti-thyroid medications (carbimazole or propylthiouracil) to reduce the levels of thyroid hormones. This is because patients who are hyperthyroid will have an increased risk of a 'thyroid storm'. A thyroid storm is an uncommon but serious complication of thyroid surgery which is precipitated by an acute exacerbation of thyrotoxicosis.

The patient should also undergo an indirect laryngoscopy to assess the patient's vocal cords for any abnormalities. This is because the nerves supplying the vocal cords (recurrent laryngeal nerve) are situated just adjacent to the thyroid gland and any injury will affect the vocal cords. If the goitre is suspicious for cancer, a fine needle aspiration cytology (FNAC) should be carried before surgery to confirm the diagnosis of a cancer. For huge goitres, a chest x-ray or a CT-scan should be done to check for any extension of the thyroid gland inferiorly under the sternum. This would make the surgery more extensive and longer.

After all the pre-operative assesment is done, the patient is admitted for anaesthetic assessment and surgery. During surgery an incision is made just above the collar bones. It is usually around 5-8cm in length depending on the size of the goitre.
There are two options for surgery for thyroid swellings. A hemi-thyroidectomy is performed if the patient has only a single thyroid nodule on one side or small early thyroid cancers (<1cm)>. A total thyroidectomy is performed in patients with a multi-nodular goitre involving both thyroid lobes, thyroid cancers, Graves' disease & thyrotoxicosis. Duration of surgery for a total thyroidectomy ranges from between 1-4 hours depending on the extent of disease and the size of the thyroid gland. Sometimes it might take longer if lymph node dissection is required in cancer patients.

The complications of thyroidectomy can be divided into early and late complications.

Early complications include:
- bleeding from the surgery wound
- voice change (due to swelling of the nerves)
- temporary low calcium levels (due to reduced function of parathyroid glands)
- wound infection

Late complications include:
- unsightly scar
- permanent low calcium levels (because the parathyroid glands were injured or removed during the surgery)
- permanent hoarseness of voice (injury to recurrent laryngeal nerve)
- vocal cord paralysis with difficulty breathing (injury to both recurrent laryngeal nerves)
- inability to produce a high pitched voice (injury to external branch of superior laryngeal nerve)
- permanent hypothyroidism (in total thyroidectomy, the body cannot produce any more thyroid hormones)

The parathyroid glands are located just behind the thyroid gland in the neck. Usually there are between 2 -6 parathyroid glands in everybody. Its main function is to maintain a normal level of calcium in our body. Due to its location near the thyroid gland, it has a risk of being injured or removed. However, the risk is approximately 1% only. Patients with permanent low calcium levels are treated with calcium supplement tablets.

The recurrent laryngeal nerve supplies our vocal cords. The nerve is located beside the thyroid gland on both sides. The risk of injury is approximately 1%. Injury to the nerve will cause hoarseness of voice (one sided injury) or breathing difficulty (both sided injury). Most patients will have a temporary hoarseness of voice due to swelling of the nerve during manipulation. This resolves spontaneously usually within 1 month.

The external branch of superior laryngeal nerve are located near the upper lobes of the thyroid gland on both sides. Injury to the nerve will lead to an inability to produce high-pitched voice.

Patients who have had a total thyroidectomy will need thyroid hormone supplements for life. This is because there is no more thyroid gland to produce thyroid hormones. This is usually prescribed in the form on levo-thyroxine (L-thyroxine) tablets.