Incidence of Inadvertent Parathyroid Removal During Thyroidectomy

OBJECTIVES: To assess the incidence of unintentional parathyroid removal during routine thyroidectomy and to identify factors that might predict patients at high risk. STUDY DESIGN: Retrospective review of case records. Data analyzed for incidental finding of parathyroid gland(s) in the thyroidectomy specimen and postoperative temporary or permanent hypocalcemia. METHODS: The clinical records of 220 patients undergoing thyroidectomies between January 1997 and October 1999 were reviewed. Pathology reports were screened for information on the presence of parathyroid tissue along with the thyroid specimen. Operative reports were reviewed to exclude the possibility of intentional parathyroid gland removal. Case records were scrutinized to determine whether the patient developed symptomatic hypocalcemia postoperatively. RESULTS: Nine percent of the 220 patients were found to have had inadvertent removal of parathyroid tissue. The majority of patients (95%) had two or less parathyroid glands in their specimens. The size and histological nature of the thyroid lesion were not predictive of inadvertent parathyroid removal. Of the 25 repeat operations for recurrent or persistent malignancy, 5 (20%) were found to have unintentional parathyroid removal compared with 15 (7.71%) of 195 primary thyroidectomy cases (P <.05). Nineteen percent of patients who had tracheoesophageal groove node dissection had an incidental parathyroid in their specimen compared with 7% who did not undergo tracheoesophageal groove node dissection (P = .04). None of the patients with unintentional parathyroid gland removal developed either temporary or permanent postoperative hypocalcemia. CONCLUSIONS: Inadvertent excision of a parathyroid gland(s) occurred in 9% of patients undergoing thyroidectomy in our experience. Reoperative thyroid surgery and tracheoesophageal node dissection were associated with a significantly higher risk of inadvertent parathyroid gland excision. Inadvertent parathyroidectomy did not result in symptomatic temporary or permanent hypocalcemia postoperatively.