Abstract: Objective To study the risk factors of postoperative hypocalcemia after resection of thyroid nodules. Methods A retrospective study was conducted on 124 patients undergoing thyroid nodule resection surgery, including age, gender, mass nature, lesion location （unilateral/bilateral）, lymph node dissection, surgical approach, perioperative blood calcium （adjusted and un-adjusted）, parathyroid hormone （PTH）, and blood magnesium. Patients were divided into a hypocalcemia group and a non-hypocalcemia group based on their postoperative blood calcium levels, to compare the differences between the two groups and thereby investigate the risk factors for hypocalcemia after thyroid nodule resection. Results Of the 124 cases enrolled, 12 cases （9.7%） developed hypocalcemia after the operation, with an average blood calcium of （2.10±0.08） mmol/L. After albumin correction of blood calcium level, 9 cases （7.3%） had hypocalcemia, with an average blood calcium of （2.05±0.14） mmol/L. There were no statistically significant differences between the two groups stratified by corrected blood calcium levels in terms of age, gender, mass nature, and performance of lymph node dissection （P> 0.05）. However, significant differences were observed in lesion location （unilateral/bilateral）, surgical approach, average postoperative PTH level, and presence of postoperative hypomagnesemia （P<0.05）. Conclusion For patients with postoperative hypoproteinemia, corrected blood calcium levels should be used to evaluate whether the patient needs additional calcium supplementation. Surgical procedure is a high-risk factor for postoperative hypocalcemia, and postoperative hypomagnesemia and postoperative PTH reduction are associated with hypocalcemia.

Key words: Hypocalcemia, Hypomagnesemia, Thyroid surgery, Parathyroid hormone