Thyroid Disease and Surgery

Surgery has a significant role in the management of thyroid disease in patients with simple goitre, benign thyroid tumours, hyperthyroidism (including hyperthyroidism in pregnancy), thyroid cancer and thyroid eye disease.

Goitre

Most euthyroid multinodular goitres do not necessarily require surgery or medical therapy. Serial thyroid ultrasound is useful to follow the size of individual nodules. Larger multinodular goitres require either MRI or CT scan in order to exclude tracheal compression and to assess thyroid size.

The definitive treatment for toxic multinodular goitres is biopsy of suspicious nodules or surgical excision, followed by radio-iodine therapy. Surgical treatment is recommended for benign nodules causing compressive symptoms and can be considered for toxic nodular disease and thyroid cysts.^[1]

Surgery is indicated in simple goitre if:

• There is clinical or radiological evidence of compression of surrounding structures, especially the trachea.
• There are substernal goitres, which are best removed surgically, as biopsy is difficult and clinical observation without frequent CT or MRI scans is impossible.
• The goitre continues to grow.
• There are cosmetic reasons - for example, large or unsightly.

Types of thyroid surgery^[2]

• Thyroid lobectomy to remove a nodule (solitary hot or cold nodules) and goitres that occur in one lobe.
• Partial thyroid lobectomy to remove a solitary nodule in one specific part of the thyroid.
• Thyroid lobectomy with isthmectomy for benign Hürthle cell tumours and for non-aggressive thyroid cancers.
• Subtotal thyroidectomy (leaving enough of the gland to produce some hormones) is now little used and has been replaced by total thyroidectomy or thyroid lobectomy alone.
• Total thyroidectomy for thyroid cancers, Hürthle cell tumours and also increasingly for multinodular goitres and patients with Graves' disease.
• Robotic surgery: advantages include three-dimensional imaging and tremor elimination. Robotic thyroid surgeries include thyroid lobectomy, total thyroidectomy, central compartment neck dissection, and radical neck dissection for benign and malignant thyroid diseases.^[3]

Thyroid surgery is safe in the elderly, assuming careful pre-operative evaluation and risk stratification.^[4]

Pre-operative assessment^[2]

In addition to investigations for the underlying hyperthyroidism and any thyroid swelling or nodule, serum calcium (to check parathyroid status; parathyroid hormone if there is any abnormality of calcium level) and laryngoscopy are often recommended.

Preparation for thyroid surgery

• Thyrotoxic patients should have treatment with propranolol and/or carbimazole to ensure they are euthyroid at operation.
• Potassium iodide has also been used.
• In view of the possible operative damage to the recurrent laryngeal nerve, the vocal cords should also be checked prior to thyroid surgery. The National Institute for Health and Care Excellence (NICE) recommends that intraoperative nerve monitoring during thyroid surgery should be considered, especially for more complex operations such as re-operative surgery and operations on large thyroid glands.^[5]

Complications^[6]

In recent years, thyroid surgery has become safer due to the development of new surgical, haemostatic, and other techniques such as intraoperative monitoring of the recurrent laryngeal nerve and parathyroid gland detection.

Minor complications include:

• Seroma (accumulation of clear fluid that occurs as a result of exudation after trauma or surgery).
• Scarring.
• Infection.
• Postoperative dysphagia.

Serious complications include:

• Postoperative bleeding and haematoma formation. Haematoma after thyroid surgery can lead to airway obstruction and death.^[7]
• Recurrent laryngeal nerve damage and dysphonia (transient or permanent.
• Thyrotoxic storm.
• Hypoparathyroidism.
• Hypothyroidism.
• Damage to the sympathetic trunk may occur but is rare.