Hypocalcemia after Total Thyroidectomy: Incidence and Risk Factors

ABSTRACT

PURPOSE: Postoperative hypocalcemia is a common complication of thyroidectomy. This study evaluated the incidence and risk factors for postoperative hypocalcemia after total thyroidectomy. METHODS: There were 196 consecutive patients undergoing total thyroidectomy for thyroid cancer between September 2004 and February 2005 who were enrolled in this study. Patients were divided into two groups, those remaining normocalcemic (Group I) and those who had hypocalcemia requiring treatment (Group II). Group II was subdivided into a transient hypocalcemic group (Group IIA) and a permanent hypocalcemic group (Group IIB). All groups were compared with regard to age, gender, histology, coexisting disease, T stage, bilateral lesions, primary total thyroidectomy versus secondary completion thyroidectomy, extent of lymph node dissection, and autotransplantation of the parathyroid gland. RESULTS: Among all patients, 139 (71%) were in Group I, 54 (27.5%) in Group IIA and 3 (1.5%) in Group IIB. On the multivariate analysis for risk factors compared between Group I and Group II, the T4 stage was the most significant for the development of postoperative hypocalcemia. On the univariate analysis comparing factors between Group IIA and Group IIB, the T4 stage and a complete thyroidectomy were significantly related to the development of permanent hypocalcemia. CONCLUSION: The results of this study showed that the incidence of transient hypocalcemia, after total thyroidectomy, was 27.5%, while permanent hypocalcemia was detected in 1.5% of cases. The parathyroid glands should be preserved more carefully to avoid postoperative hypocalcemia in patients with high risk factors including T4 tumors and complete thyroidectomy procedures.