Pathophysiology and predictivity of postoperative hypothyroidism

In a series of 107 patients operated on for hyperthyroidism, the incidence of postoperative hypothyroidism has been evaluated, stressing its major causes. These appear related to a decreased function of residual parenchyma, autoimmune diseases, previous irradiation of the neck, preexisting defects of the hormonogenesis. The importance of the thyroid remnant has been enphasized together with the preservation of its blood supply. A higher incidence of hypothyroidism has been observed after more extensive operations, particularly subtotal thyroidectomy, in patients affected by Graves' disease. Finally, the need for short and long term follow-up after surgery is outlined and whether a replacement therapy is required or not. It is concluded that, postoperative hypothyroidism should not be considered a complication but a predictable consequence.