Comprehensive analysis of risk factors for hypoparathyroidism in thyroid carcinoma patients

Objective: To compare the effects of two parathyroid gland protection surgical procedures on postoperative parathyroid function and investigate the other factors on the risk of postoperative hypoparathyroidism. Methods: A total of 353 patients who underwent surgical treatment for thyroid carcinoma (TC) were studied. Two different surgical procedures to preserve parathyroid glands were used: A) non-exposure of the superior parathyroid gland and B) exposure of the superior parathyroid gland. The different surgical extent was categorized as group C) total thyroidectomy only, D) total thyroidectomy + unilateral central lymph node dissection (CLND), and E) total thyroidectomy + bilateral CLND. The frequency of hypocalcemia and hypoparathyroidism was analyzed according to the different groups. Results: Procedure B, unilateral CLND and bilateral CLND were independent factors for mild hypocalcemia, and the above three factors were also independent factors for severe hypocalcaemia, whereas Hashimoto’s thyroiditis was an inverse independent factor for mild and severe hypocalcemia. Regarding hypoparathyroidism, procedure B, unilateral CLND and bilateral CLND were independent factors, whereas Hashimoto’s thyroiditis was an inverse independent factor. There were 8 cases of permanent hypoparathyroidism. Conclusion: Non-exposure of the superior parathyroid glands in situ was associated with lower hypoparathyroidism rates. When thyroidectomy plus bilateral CLND was performed, the risk of hypoparathyroidism dramatically increased. The key of the capsular dissection during total thyroidectomy was to preserve the parathyroid glands with a good blood supply in situ. Hashimoto’s thyroiditis may be a protective factor in hypoparathyroidism.