Postoperative hypoparathyroidism after total thyroidectomy for thyroid cancer

Abstract

　Postoperative hypoparathyroidism （HPT） is one of the most common complications following total thyroidectomy. Parathyroid glands （PTGs） are at risk of being damaged during total thyroidectomy with or without central neck dissection （CND） mainly due to inadvertent removal, interruption of the blood supply or hematoma formation. Careful preservation of the PTGs in situ is recommended, but not always possible in practice, and the functional results have been unpredictable. 　We retrospectively evaluated the efficacy of our surgical procedure to preserve parathyroid function and clarified the risk factors of HPT after total thyroidectomy for thyroid cancer. One hundred five patients undergoing total thyroidectomy with CND for thyroid cancer were retrospectively assessed. Postoperative transient HPT and permanent HPT were observed in 46 （44％） patients and in 19 （18％） patients, respectively. Among 60 patients in whom PTGs were preserved in situ, transient HPT and permanent HPT were observed in 20 （33％） patients and in 5 （8％） patients, respectively. Among 45 patients in whom PTGs were not preserved in situ, postoperative permanent HPT was observed in 6 patients without PTG autotransplantation, and 8 （35％） out of the 23 patients who had one PTG autotransplantation. On the other hand, none of the 12 patients who had two or more PTG autotransplantations at the time of thyroidectomy developed permanent HPT （p＝0.01）. The patients with large tumor （＞40mm） and/or gross extra glandular invasion, upper mediastinal dissection had a significantly higher risk of permanent postoperative HPT compared with the patients without these pathological features （p＜0.01）. Two or more PTGs should be autotransplanted in cases where PTG is not preserved in situ to prevent postoperative HPT after total thyroidectomy with CND, especially in cases of large tumor and/or gross extrathyroidal extension.