Risk factors of hypoparathyroidism following total thyroidectomy for thyroid cancer.

Background: The risk factors responsible for hypoparathyroidism after total thyroidectomy have not been completely defined. The present study evaluated one surgeon's personal experience of postoperative hypoparathyroidism after total thyroidectomy for thyroid cancer and predisposing risk factors of postoperative hypoparathyroidism.

Methods: We performed a retrospective analysis of 531 consecutive total thyroidectomy cases for thyroid cancer operated by single surgeon at the Center for Thyroid Cancer, National Cancer Center, Korea, from March 2003 to August 2006.

Results: Postoperative hypoparathyroidism occurred in 135 patients (25.4 %), 19 of whom (3.6 % of total patients) experienced permanent hypoparathyroidism. Parathyroid autotransplantation, bilateral central lymph node dissection, gross extrathyroidal extension, and the presence of parathyroid gland in the pathologic specimen were associated with postoperative hypoparathyroidism in multivariate analysis (p < 0.05, respectively). The presence of parathyroid gland in the pathologic specimen and the early period of surgeon's practice were statistically significant risk factors for permanent hypoparathyroidism in multivariate analysis (p < 0.05, respectively).

Conclusions: Careful surgical technique for in situ preservation of parathyroid gland and autotransplantation of inadvertently removed parathyroid gland are important, especially in case of gross extrathyroidal extension. Adequate surgical experience is also an important factor. And routine bilateral central lymph node dissection should be done thoughtfully for its effect on postoperative hypoparathyroidism.