Total thyroidectomy, which is the removal of both sides of the thyroid gland as well as the isthmus, and subtotal thyroidectomy generally requires the removal of about 90% of the gland. After total thyroidectomy, thyroid function is lost and additional thyroid hormone supplementation is required. After subtotal thyroidectomy, the residual thyroid gland will gradually regain some of its function over time. Total thyroidectomy, which involves removal of both sides of the thyroid gland as well as the isthmus, is often used for bilateral thyroid cancer, or unilateral multifocal thyroid cancer, as well as unilateral follicular or medullary carcinoma and undifferentiated carcinoma.
For subtotal thyroidectomy, which is mostly used for patients with hyperthyroidism who have failed conservative treatment, the amount of gland removed depends on the patient’s degree of hyperthyroidism, usually about 90% of the gland is removed, that is, about a thumb’s worth of thyroid tissue remains in each superior thyroid gland to protect the parathyroid glands and the laryngeal nerve, which is sufficient to maintain normal physiological function after surgery and is not likely to lead to recurrence. For patients with nodular goiter, more thyroid tissue should be preserved appropriately. After total thyroidectomy, thyroid gland function is lost and additional thyroid hormone supplementation is needed, usually with eugenol. The dose of levothyroxine sodium tablets should be adjusted in time.