Subtotal thyroidectomy is a surgical procedure of the thyroid gland, mainly used to diagnose benign thyroid disease. Subtotal thyroidectomy, which can include the lobes of the gland plus removal of the isthmus, is mainly performed for benign thyroid disorders. For example, thyroid nodules or thyroid adenomas less than 1.5 cm in diameter are recommended, and subtotal thyroidectomy is recommended if the thyroid tumor is well defined and confined to one thyroid lobe. Patients who undergo subtotal thyroidectomy need regular postoperative review of thyroid function and, in the case of combined hypothyroidism, lifelong oral levothyroxine sodium tablets to supplement thyroid therapy.