B27. Frequent complications following thyroid surgery.

For information on thyroid tumours and nodules, see topic B6.

Indications of thyroid surgery:

• Suspicion of malignancy
• Signs of compression of trachea/oesophagus
• Solitary hormone-producing adenoma (hot nodule) > 3 cm
• Nodular goitre
• Retrosternal propagation (goitre which extends into the thorax)
• Medical treatment failure of diffuse goitre
• Large Graves goitre
• Multinodular or diffuse large hormone-producing goitre

Preoperative preparations

Thyroid imaging (ultrasound), TSH to determine hormone status, and laryngeal examination (laryngoscopy) are essential before thyroid surgery.

Before thyroid surgery, a couple of preoperative medications are obligatory to minimise the risk of thyroid storm intraoperatively. These include a thyreostatic drug, a beta blocker (propranolol), and iodine. Administration of vitamin D and calcium supplementation may reduce the risk of symptomatic hypocalcaemia postoperatively.

Procedures

• Total thyroidectomy is used for thyroid cancer or large goitre.
• Subtotal thyroidectomy is used for benign conditions which affect the entire gland (Graves, toxic multinodular goitre)
  • The part of the thyroid adjacent to the parathyroid glands and the laryngeal nerves is spared to reduce the risk of complications
• Hemithyroidectomy/lobectomy is used for low-risk thyroid cancer and single nodules

Complications of thyroid surgery

• Hoarseness
• Recurrent or superior laryngeal nerve injury
• Haematoma
• Hypoparathyroidism
• Hypothyroidism
• Bleeding (air embolism)
• Tracheal injury (rare)
• Thyroid storm (rare when preoperative medication is given properly)

Hypoparathyroidism is a common complication of thyroid surgery, although it’s transient in most cases. It can occur due to direct trauma, damage to the blood supply, or removal of the glands during surgery. The resulting hypocalcaemia may cause anything from perioral numbness to generalised tetany or seizures and should be treated with supplements if symptomatic. Patient’s calcium level should be monitored after surgery.

Cervical haematoma is a possibly life-threatening postoperative complication. After surgery, the patient should be routinely examined for signs of haematoma. A drain may be placed to reduce the risk for haematoma development.

Hoarseness is common after thyroid surgery, and likely due to vocal cord oedema due to endotracheal intubation. This is transient and resolves after a few days. However, injury to the superior or recurrent laryngeal nerves may also cause hoarseness. Injury to the superior nerve only produces vocal fatigue and changes in voice quality, but injury to the recurrent nerve is more concerning as it may cause swallowing difficulties, and increased risk of aspiration. Injury may be transient but is often permanent. Nerve injuries identified intraoperatively may be attempted repaired.

Patients who undergo total or subtotal thyroidectomy need hormone replacement indefinitely. If lobectomy or hemithyroidectomy were performed, the remaining thyroid may produce sufficient thyroid hormone. This must be monitored.