Incidental parathyroidectomy during thyroid resection: incidence, risk factors, and outcome

Background and Objectives: Thyroidectomy is a commonly performed procedure for thyroid problems. Inadvertent removal of the parathyroid glands is one of its recognized complications, which occurs more frequently in certain high-risk patients. The aim of this study was to identify the incidence, risk factors, and clinical relevance of incidental parathyroidectomy during thyroid surgery. Design and Setting: A retrospective review of thyroid operations performed at a tertiary referral hospital between January 2004 and December 2008. Methods: Pathology reports were reviewed to identify the specimens that included parathyroid tissue and underlying thyroid pathology. Postoperative calcium levels were reviewed in these patients. Results: During the study period, 287 thyroidectomies were performed and 47 (16.4%) patients had incidentally removed parathyroid glands. Risk factors for inadvertent parathyroid resection included total thyroidectomy (P=.0001), Hashimoto thyroiditis (P=.004), and extrathyroidal spread (P=.0003). Postoperative hypocalcemia occurred in 18 (38.3%) of the patients in whom the parathyroid gland was removed inadvertently and in 48 (20%) of the rest of the patients (P=.0123). Conclusion: The incidence of incidental removal of parathyroid tissue during thyroidectomy is 16.4%. Total thyroidectomy, extrathyroidal extension of the tumor, and thyroiditis were found to be the risk factors. Hypocalcemia was significantly higher among patients who had inadvertent parathyroidectomy.